JP2020172014A - Electric work machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric working machine capable of reducing power consumption when the electric working machine is not used. One aspect of the present disclosure is an electric work machine including a drive unit that is driven by using power from a power source, and includes a control unit, a power supply for the control unit, and an operating state determination unit. .. The power supply for the control unit includes a first conversion power supply and a second conversion power supply. When the operation state determination unit determines that the operation state of the control unit is the control operation state, the power supply for the control unit shifts to the first conversion state, and the operation state determination unit operates the control unit. Is configured to shift to the second conversion state when is determined to be in the low power operating state. The second conversion state is a conversion state in which the voltage conversion by the first conversion power supply is stopped and at least the second conversion power supply is used to supply the power for the control unit to the control unit. [Selection diagram] Fig. 2

Description

The present disclosure relates to an electric working machine.

As an electric work machine, there is one provided with a drive unit driven by power supply from a battery (power source) (Patent Document 1). The electric work machine includes a control unit that controls a drive unit (for example, a motor, a heater, etc.) and a power supply for the control unit that converts electric power from a battery into a voltage and supplies electric power to the control unit. In order to suppress over-discharging of the battery when not in use, this electric work machine can reduce the power consumption of the control unit and the power supply for the control unit to zero by cutting off the power supply from the power supply for the control unit. it can.

When the power supply from the power supply for the control unit is cut off, (1) communication between the electric work machine and external equipment becomes impossible when the power supply is cut off, and (2) from the reoperation of the trigger to the movement of the motor. There is a possibility that a time lag may occur and the usability may decrease.

On the other hand, when the electric work machine is not in use, it is conceivable to use a method of shifting the control unit to a low power operation state (so-called sleep mode) instead of shutting off the power supply from the power supply for the control unit. .. For example, the operating state of the control unit can be changed to a control operating state in which the drive unit is controlled when the user operates the electric work machine and a low power operating state for reducing the power consumption of the control unit. It is conceivable to use the control unit. That is, this control unit is configured to be able to shift to a low power operation state in order to suppress over-discharging of the battery.

Japanese Unexamined Patent Publication No. 2006-341325

However, in the above electric work machine, although the power consumption of the control unit can be reduced by shifting the operation state of the control unit to the low power operation state, the power supply for the control unit performs the power conversion operation, so that the power supply for the control unit is performed. It may not be possible to reduce the power consumption in.

For example, when a linear regulator is used as the power supply for the control unit, the loss Ls (= (Vin-Vout) × Io) in the linear regulator increases as the output voltage (power supply voltage) of the battery increases. Vin is the input voltage to the linear regulator (in other words, the output voltage of the battery), Vout is the output voltage from the linear regulator, and Io is the output current of the linear regulator. That is, during normal operation, the power consumption associated with the loss Ls is generated in the power supply for the control unit in accordance with the increase in the power supply voltage.

On the other hand, in order to suppress an increase in power consumption due to an increase in the power supply voltage, it is conceivable to use a switching regulator such as a DC-DC converter as the power supply for the control unit. However, in general, since these switching regulators consume a large amount of operating current, even if the control unit shifts to the sleep mode, the operating current of the switching regulator is large, so that the overall low power consumption is low. It becomes difficult to convert.

In other words, even if the control unit shifts to sleep mode and the power consumption of the control unit can be reduced when the electric work machine is not in use, the power consumption of the power supply for the control unit exists, so that the battery (power supply) Power will be consumed.

Therefore, in one aspect of the present disclosure, it is desirable to be able to provide an electric work machine capable of reducing power consumption when the electric work machine is not in use.

One aspect of the present disclosure is an electric work machine including a drive unit that is driven by using power from a power source, and includes a control unit, a power supply for the control unit, and an operating state determination unit.
The control unit is configured to control the drive unit. The power supply for the control unit is configured to voltage-convert the power supply power from the power supply and supply the power for the control unit after voltage conversion to the control unit. The control unit is configured to be switchable to a plurality of operating states. The plurality of operating states include at least a control operating state that controls the drive unit and a low power operating state that consumes less power than the control operating state.

The power supply for the control unit includes a first conversion power supply and a second conversion power supply. The first conversion power supply is configured to be able to supply the maximum control current, which is the maximum current consumption of the control unit in the control operating state, when converting the power supply power from the power supply into a voltage. The second conversion power supply can supply the maximum current at low power consumption, which is the maximum current consumption of the control unit in the low power operation state, and the maximum output current is the maximum at the time of control when converting the power supply power from the power supply into voltage. It is configured to be smaller than the current.

The operation state determination unit is configured to determine whether the operation state of the control unit is a control operation state or a low power operation state.
Further, when the operation state determination unit determines that the operation state of the control unit is the control operation state, the power supply for the control unit shifts to the first conversion state, and the operation state determination unit determines that the control unit is in the control operation state. When the operating state is determined to be the low power operating state, it is configured to shift to the second conversion state. The first conversion state is a conversion state in which at least the first conversion power source is used to supply power for the control unit to the control unit. The second conversion state is a conversion state in which the voltage conversion by the first conversion power supply is stopped and at least the second conversion power supply is used to supply the power for the control unit to the control unit.

When the control unit is in a low power operation state, this electric work machine does not use the first conversion power supply for voltage conversion by the power supply for the control unit, so that the power consumption in the first conversion power supply can be suppressed. Therefore, when the operating state of the control unit shifts from the control operating state to the low power operating state when the electric work machine is not used, not only the power consumption of the control unit is reduced but also the power consumption of the first conversion power supply is reduced. Since the consumption can be reduced, the power consumption when the electric work machine is not used can be reduced.

Next, in the above-mentioned electric work machine, the power supply for the control unit may be configured to shift the operating state to the first conversion state when the electric work machine is operated by the user.
That is, when the operating state of the power supply for the control unit is the second conversion state and the electric work machine is operated by the user, the power supply for the control unit secondly converts the operating state of the power supply for the control unit. The state shifts to the first conversion state. As a result, since the power for the control unit is supplied to the control unit by at least the first conversion power supply, it is possible to receive the supply of the maximum current during control required in the control operation state, and the drive unit can be controlled. .. The operation of the electric work machine by the user includes, for example, the operation of the trigger switch by the user.

Next, the above-mentioned electric work machine may include a first backflow current suppressing unit that suppresses the inflow of the backflow current to the output unit of the first conversion power supply. This electric work machine can suppress the current output from the second conversion power supply from flowing into the output unit of the first conversion power supply. The first backflow current suppression unit may be configured by using, for example, a switching element such as a diode or FET connected in series with the first conversion power supply.

Next, in the above-mentioned electric work machine, the power supply for the control unit may include a first current path and a second current path. The first current path is a part of the current path from the power source to the control unit, and is a current path provided with the first conversion power source. The second current path is a current path that is connected in parallel to the first current path and is provided with a second conversion power supply.

Each of the first conversion power supply and the second conversion power supply converts the power supply power into the control unit power of the control unit voltage lower than the power supply voltage output by the power supply, and supplies the control unit power after voltage conversion. It is configured to be possible.

The first conversion state of the power supply for the control unit may be a state in which the power for the control unit is supplied to the control unit by using the first conversion power supply at least via the first current path. The second conversion state of the power supply for the control unit is a state in which the voltage conversion by the first conversion power supply is stopped and the power for the control unit is supplied to the control unit by using the second conversion power supply at least via the second current path. There may be.

In this electric work machine, when the control unit is in the low power operation state, the power supply for the control unit shifts to the second conversion state and stops the voltage conversion using the first conversion power supply, so that the first conversion power supply is used. Power consumption can be suppressed. Therefore, when the operating state of the control unit shifts from the control operating state to the low power operating state when the electric work machine is not used, not only the power consumption of the control unit but also the power consumption of the first conversion power supply is consumed. Since it can be reduced, the power consumption when the electric work machine is not used can be reduced.

Next, the above-mentioned electric work machine may be provided with a second backflow current suppression unit. The second backflow current suppressing unit is configured to suppress the inflow of the backflow current to the output unit of the second conversion power supply between the second conversion power supply and the control unit in the second current path.

This electric work machine can suppress the current output from the first conversion power supply from flowing toward the output unit of the second conversion power supply as a backflow current. The second backflow current suppression unit may be configured by using, for example, a switching element such as a diode or FET connected in series with the second conversion power supply.

Next, in the above-mentioned electric working machine, the output voltage of the first conversion power supply and the output voltage of the second conversion power supply may have the same voltage value. This electric work machine can maintain a constant voltage applied to the control unit regardless of whether the first conversion power supply is used or the second conversion power supply is used, and the first conversion power supply and the second conversion power supply can be maintained. It is possible to suppress malfunction of the control unit due to fluctuations in the applied voltage when switching between.

Next, in the above-mentioned electric work machine, the operation state determination unit is configured to be able to receive the first state notification signal and the second state notification signal, and when the first state notification signal is received, the operation state notification signal is received. When it is determined that the operating state of the control unit is the control operating state and the second state notification signal is received, it may be determined that the operating state of the control unit is the low power operating state. The first state notification signal is a notification signal indicating that the operating state of the control unit is the control operating state. The second state notification signal is a notification signal indicating that the operating state of the control unit is a low power operating state. In this electric work machine, the operation state determination unit can determine the operation state of the control unit based on the first state notification signal and the second state notification signal.

Next, in the above-mentioned electric working machine, the power supply for the control unit may include a third current path, a bypass current path, and a common current path. The third current path is a part of the current path from the power source to the control unit, and is a current path provided with the first conversion power source. The bypass current path is a current path connected in parallel to the third current path. The common current path is a current path that is connected in series to each of the third current path and the bypass current path and is provided with a second conversion power supply.

The first conversion power supply is configured to be able to voltage-convert the power supply power into the intermediate power supply power and supply the intermediate power supply power after the voltage conversion. The intermediate power supply is power supplied at an intermediate power supply voltage lower than the power supply voltage output by the power supply.

The second conversion power source is configured to be able to voltage-convert the power source power or the intermediate power source power into the power for the control unit and supply the power for the control unit after the voltage conversion. Here, the power for the control unit is power supplied at a voltage for the control unit that is lower than the intermediate power supply voltage.

The first conversion state of the power supply for the control unit is a state in which the power for the control unit is supplied to the control unit by using the first conversion power supply and the second conversion power supply via at least the third current path and the common current path. In the second conversion state of the control unit power supply, the voltage conversion by the first conversion power supply is stopped, and the control unit power is supplied to the control unit by using the second conversion power supply at least via the bypass current path and the common current path. It is in a state of doing.

In this electric work machine, when the control unit is in the low power operation state, the power supply for the control unit shifts to the second conversion state and stops the voltage conversion using the first conversion power supply, so that the first conversion power supply is used. Power consumption can be suppressed. Therefore, when the operating state of the control unit shifts from the control operating state to the low power operating state when the electric work machine is not used, not only the power consumption of the control unit but also the power consumption of the first conversion power supply is consumed. Since it can be reduced, the power consumption when the electric work machine is not used can be reduced.

Next, in the above-mentioned electric work machine, the operation state determination unit may be configured to determine whether or not the bypass current flowing in the bypass current path is larger than a predetermined operation reference value. Further, the operation state determination unit determines that the operation state of the control unit is the control operation state when the bypass current is larger than the operation reference value, and when the bypass current is equal to or less than the operation reference value, the control unit determines. It may be determined that the operating state of is a low power operating state. In this electric work machine, the operating state determination unit can determine the operating state of the control unit based on the comparison result between the bypass current and the operation reference value.

Next, in the above-mentioned electric work machine, the operation state determination unit is configured to be able to receive the first state notification signal and the second state notification signal, and the bypass current is larger than the operation reference value, or When the first state notification signal is received, it is determined that the operation state of the control unit is the control operation state, and when the bypass current is equal to or less than the operation reference value and the second state notification signal is received, control is performed. It may be determined that the operating state of the unit is a low power operating state. The first state notification signal is a notification signal indicating that the operating state of the control unit is the control operating state. The second state notification signal is a notification signal indicating that the operating state of the control unit is a low power operating state. In this electric work machine, the operation state determination unit determines the operation state of the control unit based on the first state notification signal and the second state notification signal in addition to the comparison result between the bypass current and the operation reference value. Is possible.

Next, in the above-mentioned electric work machine, the power supply includes a plurality of battery packs, and may include a plurality of voltage output units that output different voltages, and the first conversion power supply and the second conversion power supply may include. The output voltage of any one of the plurality of voltage output units may be converted into a voltage.

That is, by adopting a configuration in which the power supply includes a plurality of battery packs, the maximum voltage that can be output can be increased according to the number of battery packs. This allows the electric work machine to operate at a higher output based on a higher voltage.

Even in such an electric work machine, when the control unit is in a low power operation state, the first conversion power supply is not used for voltage conversion in the control unit power supply, so that the power consumption in the first conversion power supply can be suppressed. , It is possible to reduce the power consumption when the electric work machine is not used.

Next, in the above-mentioned electric work machine, the second conversion power supply may be connected to the voltage output unit having the smallest output voltage among the plurality of voltage output units. As a result, the amount of voltage change in the voltage conversion in the second conversion power supply can be reduced, and the power loss due to the voltage conversion can be reduced as compared with the case where the amount of voltage change is large.

Next, in the above-mentioned electric work machine, the first conversion power supply is connected to the voltage output unit having an output voltage larger than the output voltage of the voltage output unit to which the second conversion power supply is connected among the plurality of voltage output units. May be done. As a result, the amount of power that can be output from the first conversion power supply becomes larger than the amount of power that can be output from the second conversion power supply, and the first conversion power supply is sufficient for the control unit as compared with the second conversion power supply. Power can be supplied.

It is a perspective view of the electric work machine of an embodiment. It is a block diagram which shows the electric structure of the electric work machine in 1st Embodiment. It is a timing chart which showed the relationship between the switching of the operation state in a control part, and the current consumption in a power source for a control part in 1st Embodiment. It is a block diagram which shows the electric structure of the electric work machine in 2nd Embodiment. It is a timing chart showing the relationship between the switching of the operating state in the control unit and the current consumption in the power supply for the second control unit in the second embodiment. It is a block diagram which shows the electric structure of the electric work machine in 3rd Embodiment. 6 is a timing chart showing the relationship between the switching of the operating state in the control unit and the current consumption in the power supply for the third control unit in the third embodiment. It is a block diagram which shows the electric structure of the electric work machine in 4th Embodiment. It is a timing chart showing the relationship between the switching of the operating state in the control unit and the current consumption in the power supply for the fourth control unit in the fourth embodiment. It is a block diagram which shows the electric structure of the electric work machine in 5th Embodiment. It is a block diagram which shows the electric structure of the electric work machine in 6th Embodiment.

Hereinafter, embodiments to which the present disclosure has been applied will be described with reference to the drawings.
It should be noted that the present disclosure is not limited to the following embodiments, and it goes without saying that various forms can be adopted as long as they belong to the technical scope of the present disclosure.

[1. First Embodiment]
[1-1. overall structure]
The electric work machine 1 shown in FIG. 1 is configured as, for example, a rechargeable impact driver. The rechargeable impact driver is driven by electric power supplied from the battery pack 100, which will be described later. Rechargeable impact drivers are used, for example, to rotate fasteners such as screws and bolts. The rechargeable impact driver is configured to be able to generate a large torque in the rotation direction by giving a blow in the rotation direction according to the load when the fastening component is rotating.

As shown in FIG. 1, the electric work machine 1 of the present embodiment includes a main body 2 and a battery pack 100. The battery pack 100 is configured to be removable from the main body 2.
The main body 2 includes a housing 3. The housing 3 includes two half-split housings 3a and 3b divided into left and right, and these half-split housings 3a and 3b are combined to form a housing 3. The housing 3 may be, for example, an injection molded member containing a resin.

The main body 2 includes a first accommodating portion 5, a grip portion 6, and a second accommodating portion 7. The first accommodating portion 5 is provided with a chuck sleeve 8, an LED 10, and a rotation direction switching operation portion 11. The LED 10 irradiates the outside of the electric work machine 1 with light. The grip portion 6 extends from the first accommodating portion 5. The second accommodating portion 7 extends from the grip portion 6. The second accommodating portion 7 is provided with a battery mounting portion 7a to which the battery pack 100 is attached / detached.

The battery pack 100 includes a secondary battery (not shown) that can be repeatedly charged and discharged. The secondary battery may be, for example, a lithium ion battery or a secondary battery of a type different from that of the lithium ion battery. The output voltage VB of the battery pack 100 (hereinafter, also referred to as the battery voltage VB) is 36 [V].

The grip portion 6 is gripped by the user of the electric work machine 1 when the user of the electric work machine 1 uses the electric work machine 1. The grip portion 6 is provided with a trigger operation portion 9. The user can pull the trigger operation unit 9 with a finger (trigger ON operation) while gripping the grip unit 6.

[1-2. Electrical configuration of electric work machine]
The electrical configuration of the electric working machine 1 will be described with reference to FIG. FIG. 2 shows the electrical configuration of the electric work machine 1 in which the battery pack 100 is mounted on the main body 2.

As shown in FIG. 2, the electric work machine 1 includes a motor 61, a control unit 62, a motor drive unit 63, a power supply for the control unit 64, and an operating state determination unit 75. The electric work machine 1 includes a motor energization path LM, a voltage conversion path LC, a first current path LC1, and a second current path LC2.

The motor energization path LM is an energization path from the positive electrode of the battery pack 100 to the negative electrode of the battery pack 100 via the motor 61 and the motor drive unit 63. The first end of the voltage conversion path LC is connected to the first branch point P1 of the motor energization path LM, and the second end is connected to the power supply 64 for the control unit (specifically, the second branch point P2). The first current path LC1 and the second current path LC2 are provided in the power supply 64 for the control unit.

The motor 61 is a brushed motor. The motor 61 is driven by current energization using electric power supplied from the battery pack 100 via the motor energization path LM.
The motor drive unit 63 includes a switching unit (FET or the like) connected in series to the motor energization path LM. The motor drive unit 63 switches the switching unit to an energized state (ON state) or a non-energized state (OFF state) based on the motor drive command Smd from the control unit 62, and sets the motor energized path LM to the energized state or non-energized state. It is configured to be switchable to the state.

The control unit 62 includes a microcomputer including a CPU, a recording unit (ROM, RAM), a signal input / output unit, and the like. The control unit 62 receives power supply via the constant voltage supply line 81 described later. The control unit 62 executes various processes by the CPU executing various programs stored in the recording unit. The various processes include, for example, a motor control process for controlling the motor 61 by a motor drive command Smd, an abnormality determination process for determining whether or not an abnormality has occurred in the electric work machine 1, and a plurality of operations for operating the control unit 62. The operation state switching process for switching to one of the states is included.

The plurality of operating states include at least a control operating state and a low power operating state. The control operation state is an operation state in which motor control processing, abnormality determination processing, and the like can be executed. In the control operation state, the control unit 62 AD-converts the measurement signals from various sensors (not shown) for measuring the state (motor temperature, motor current, etc.) of each part in the electric work machine 1 and executes abnormality determination processing and the like. To do. In the controlled operating state, the constant voltage Vcc supplied from the constant voltage supply line 81 becomes the reference voltage for AD conversion, so that high voltage accuracy is required so that the voltage error can be reduced. The low power operating state is an operating state in which power consumption is lower than that of the control operating state. The low power operation state is a so-called sleep state, which is an operation state in which the power consumption of the control unit 62 is reduced. In the low power operation state, the control unit 62 does not perform AD conversion or the like, and does not perform comparison processing between the reference voltage (constant voltage Vcc) and the measurement signals of various sensors. In the low power operating state, the constant voltage Vcc supplied from the constant voltage supply line 81 is not used as the reference voltage for AD conversion, so that the required voltage accuracy is lower than that in the control operating state. The maximum current consumption of the control unit 62 in the control operating state (maximum current ICmax during control) is 100 mA, and the maximum current consumption of the control unit 62 in the low power operation state (maximum current ISmax during low power consumption) is 50 μA.

The control unit 62 changes the operating state of the control unit 62 when the state in which the user does not perform an operation (such as the operation of the trigger operation unit 9) continues for a predetermined sleep determination time Ts (for example, 5 minutes). , It is configured to shift from the control operating state to the low power operating state.

The control unit 62 is configured to output a state notification signal Smo according to the operating state during execution. That is, when the control unit 62 shifts to the control operation state, it outputs a state notification signal Smo (hereinafter, also referred to as a first state notification signal Smo1) indicating that it is in the control operation state, and when it shifts to the low power operation state, It outputs a status notification signal Smo (hereinafter, also referred to as a second status notification signal Smo2) indicating that it is in a low power operation state. The control unit 62 outputs the state notification signal Smo to at least the control unit power supply 64 (specifically, the first backflow current suppression unit 69 described later) and the operating state determination unit 75.

The trigger operation unit 9 is configured to output a trigger signal Str when a pull operation is performed by the user. The trigger operation unit 9 is configured to output a trigger signal Str having the same potential as the ground potential during execution of the pull operation by the user. The trigger signal Str is output to at least the control unit 62 and the operation state determination unit 75.

The operation state determination unit 75 is configured to determine whether the operation state of the control unit 62 is a control operation state or a low power operation state. The operation state determination unit 75 is configured to input the state notification signal Smo and the trigger signal Str, and output the energization command signal Sc1 according to the respective states of the state notification signal Smo and the trigger signal Str.

When the first state notification signal Smo1 is input or the trigger signal Str is input (in other words, the pulling operation by the user is being executed), the operation state determination unit 75 of the control unit 62 It is configured to determine that the operating state is the control operating state. The operation state determination unit 75 operates the control unit 62 when the second state notification signal Smo2 is input and the trigger signal Str is not input (in other words, the pulling operation by the user is not executed). It is configured to determine that the state is a low current operating state. The operation state determination unit 75 is configured to output an energization command signal Sc1 according to the determination result.

[1-3. Power supply for control unit]
The power supply 64 for the control unit converts the battery voltage VB from the battery pack 100 into a voltage, and outputs the constant voltage Vcc after the voltage conversion to the constant voltage supply line 81. The constant voltage Vcc is supplied to each part (control unit 62, etc.) of the electric working machine 1 via the constant voltage supply line 81. In this embodiment, the constant voltage Vcc is 5 [V]. The electric power supplied from the control unit power supply 64 via the constant voltage supply line 81 is used, for example, as operating power for the control unit 62 and the like.

The control unit power supply 64 includes a first conversion power supply 65, a first switching unit 67, a first backflow current suppression unit 69, a second conversion power supply 71, a second backflow current suppression unit 73, a first current path LC1, and a second current. The route LC2 is provided.

The first current path LC1 is a part of the current path from the battery pack 100 to the control unit 62, and is a current path provided with the first conversion power supply 65. The second current path LC2 is a current path that is connected in parallel to the first current path LC1 and is provided with a second conversion power supply 71. The first end of the first current path LC1 and the first end of the second current path LC2 are connected to the second branch point P2 and connected to the voltage conversion path LC, respectively. The second end of the first current path LC1 and the second end of the second current path LC2 are connected to the third branch point P3 and connected to the constant voltage supply line 81, respectively.

In the first current path LC1, from the second branch point P2 to the third branch point P3, the first switching unit 67, the first conversion power supply 65, and the first backflow current suppression unit 69 are arranged in this order.
The first conversion power supply 65 includes a DC-DC converter that converts a DC voltage into a voltage and outputs the voltage. The first conversion power supply 65 converts the battery voltage VB input to the input unit 65a into a voltage, and outputs the constant voltage Vcc after the voltage conversion from the output unit 65b. The first conversion power supply 65 outputs 5 [V] as a constant voltage Vcc. The constant voltage Vcc is supplied to each part (control unit 62, etc.) of the electric working machine 1 via the constant voltage supply line 81. The first conversion power supply 65 has a performance of a maximum output current of 100 mA or more when converting a voltage, and is configured to be able to supply the maximum current consumption (maximum current ICmax during control) in the control unit 62 in the control operating state. Has been done. The power consumption required for voltage conversion in the first conversion power supply 65 is the power consumption corresponding to the current consumption on the order of mA.

The first switching unit 67 is provided between the second branch point P2 and the first conversion power supply 65 in the first current path LC1. The first switching unit 67 is configured to include a switching unit (FET or the like) connected in series with the first current path LC1. The first switching unit 67 is configured to be able to switch the switching unit to an energized state (ON state) or a non-energized state (OFF state) based on the energization command signal Sc1 from the operation state determination unit 75. The first switching unit 67 is configured to be able to switch between an energized state and a non-energized state with respect to the energization from the second branch point P2 to the first conversion power supply 65 in the first current path LC1. As a result, the first switching unit 67 is configured to be able to switch the input state of the battery voltage VB to the first conversion power supply 65 based on the energization command signal Sc1.

The first backflow current suppression unit 69 is provided between the first conversion power supply 65 and the third branch point P3 in the first current path LC1. The first backflow current suppression unit 69 includes a diode 69a connected in series with the first current path LC1 and a switching unit 69b in parallel with the diode 69a. The diode 69a is configured to allow energization from the first conversion power source 65 to the third branch point P3 and suppress energization from the third branch point P3 to the first conversion power source 65. Here, if the switching unit 69b is used as an FET, a parasitic diode that is always present in the FET may be used as the diode 69a. The first backflow current suppression unit 69 switches the switching unit to an energized state (ON state) or a non-energized state (OFF state) based on the state notification signal Smo from the control unit 62, and energizes the first current path LC1. It is configured to be switchable between the state and the non-energized state.

As a result, the first backflow current suppression unit 69 allows the current energization from the output unit 65b of the first conversion power supply 65 to the constant voltage supply line 81 via the diode 69a by turning the switching unit 69b into a non-energized state. At the same time, it is possible to suppress the inflow of the backflow current from the third branch point P3 to the output unit 65b of the first conversion power supply 65. When the current is applied from the output unit 65b to the constant voltage supply line 81 via the diode 69a, the constant voltage Vcc output from the output unit 65b drops by the forward voltage (Vf) of the diode 69a. It is output to the constant voltage supply line 81. Further, in the first backflow current suppression unit 69, when the switching unit 69b is energized, the constant voltage Vcc output from the output unit 65b of the first conversion power supply 65 does not drop at the diode 69a, and the constant voltage is constant. The constant voltage Vcc is output to the supply line 81.

In the second current path LC2, the second conversion power supply 71 and the second backflow current suppression unit 73 are arranged in this order from the second branch point P2 to the third branch point P3.
The second conversion power supply 71 includes a series regulator that converts a DC voltage into a voltage and outputs the voltage. The second conversion power supply 71 converts the battery voltage VB input to the input unit 71a into a voltage, and outputs the constant voltage Vcc after the voltage conversion from the output unit 71b. The second conversion power supply 71 outputs 5 [V] as a constant voltage Vcc. The constant voltage Vcc is supplied to each part (control unit 62, etc.) of the electric working machine 1 via the constant voltage supply line 81. The second conversion power supply 71 has a performance of a maximum output current of 50 μA or more when converting voltage, and can supply the maximum current consumption (maximum current ISmax at low power consumption) of the control unit 62 in a low power operation state. It is configured in. The power consumption required for voltage conversion in the second conversion power supply 71 is the power consumption corresponding to the current consumption on the order of μA. Since the maximum output current of the second conversion power supply 71 is smaller than the maximum control current ICmax, the power consumption required for voltage conversion is smaller than that of the first conversion power supply 65.

The second backflow current suppression unit 73 is provided between the second conversion power supply 71 and the third branch point P3 in the second current path LC2. The second backflow current suppression unit 73 includes a diode connected in series with the second current path LC2. This diode is arranged so as to allow energization from the second conversion power source 71 to the third branch point P3 and suppress energization from the third branch point P3 to the second conversion power source 71. Therefore, the second backflow current suppression unit 73 outputs a voltage dropped from the constant voltage Vcc by the forward voltage (Vf) of the diode from the output unit 71b of the second conversion power supply 71 to the constant voltage supply line 81. It is configured to allow and suppress the inflow of backflow current from the third branch point P3 to the output unit 71b of the second conversion power supply 71.

When the energization command signal Sc1 indicating that the control unit is in the control operation state is input from the operation state determination unit 75, the control unit power supply 64 having such a configuration uses the first conversion power supply 65 and the second conversion power supply 71. By outputting the constant voltage Vcc, the state shifts to the state of supplying the power for the control unit to the control unit 62 (hereinafter, also referred to as the first conversion state).

Further, when the operation state determination unit 75 inputs the energization command signal Sc1 indicating that the power supply 64 is in the low power operation state, the power supply 64 for the control unit stops the voltage conversion by the first conversion power supply 65 and is the second conversion power supply. By outputting the constant voltage Vcc using the 71, the state shifts to the state of supplying the power for the control unit to the control unit 62 (hereinafter, also referred to as the second conversion state).

[1-4. Change status of current consumption due to switching of operating state in the control unit]
Next, the change state of the current consumption Ia in the control unit power supply 64 due to the switching of the operating state in the control unit 62 will be described with reference to FIG.

FIG. 3 shows the switching of the operating state of the control unit 62 and the change status of the current consumption Ia with the passage of time, with the time point when the pulling operation of the trigger operation unit 9 by the user is completed is set to time t0.
During the period from the time t0 to the time t1 when the sleep determination time Ts has elapsed, if the state in which the trigger operation unit 9 is not pulled by the user continues, the control unit 62 controls the operation state. The process for shifting to the low power operating state (operating state switching process) is started.

When the operation state switching process is started, the control unit 62 first executes a process of sequentially stopping the power supply to various devices and circuits provided in the electric work machine 1. Along with this, the current consumption Ia gradually decreases from the initial current consumption Ia0 (time t1 to t2), and the current corresponding to the current consumption (first current change amount ΔIa1) in various devices before stopping is reduced. At this time, the current consumption Ia is reduced to the first current consumption Ia1.

Next, the control unit 62 executes a process of outputting a state notification signal Smo indicating that it is in a low power operation state as one step in the operation state switching process (time t2). As a result, the voltage conversion by the first conversion power supply 65 is stopped, and the current corresponding to the current consumption amount (second current change amount ΔIa2) required for the voltage conversion by the first conversion power supply 65 is reduced, and the current consumption at this time is reduced. The current Ia decreases to the second current consumption Ia2.

Next, the control unit 62 executes a process of shifting the control unit 62 itself to the low power operation state (sleep mode) as one step in the operation state switching process (time t3). As a result, the current corresponding to the difference between the current consumption in the control operation state and the current consumption in the low power operation state in the control unit 62 is reduced, and the current corresponding to the current consumption (third current change amount ΔIa3) is reduced. The current consumption Ia at this time is reduced to the third current consumption Ia3.

By executing these, the control unit 62 maintains the low power operation state until the operation state switching process is completed and the trigger operation unit 9 is pulled by the user.
After that, when the trigger operation unit 9 is pulled by the user (time t4), the trigger signal Str is input to the control unit 62. As a result, the control unit 62 itself shifts from the low power operation state (sleep mode) to the control operation state (wakeup). Then, the wake-up control unit 62 starts the operation state switching process for shifting the operation state from the low power operation state to the control operation state. Further, when the trigger signal Str from the trigger operation unit 9 is also input to the operation state determination unit 75 and the energization command signal Sc1 from the operation state determination unit 75 is input to the control unit power supply 64, the first conversion power supply is supplied. The voltage conversion by 65 is started. Therefore, with the wake-up of the control unit 62 and the voltage conversion operation of the first conversion power supply 65, the current consumption Ia gradually increases to the first current consumption Ia1 (time t4 to t5).

Next, as one step in the operation state switching process, the control unit 62 executes a process of outputting a state notification signal Smo (first state notification signal Smo1) indicating that the control operation state is in effect (time t5). As a result, the constant voltage Vcc output from the output unit 65b of the first conversion power supply 65 is supplied to the constant voltage supply line 81 without a voltage drop.

Next, the control unit 62 executes a process of sequentially starting power supply to various devices and circuits provided in the electric work machine 1 as one step in the operation state switching process (time t6). Along with this, the current consumption Ia increases to the initial current consumption Ia0.

As described above, in the electric working machine 1 of the present embodiment, when the operating state of the control unit 62 shifts to the low power operating state, the voltage conversion of the first conversion power supply 65 is stopped, so that the second conversion is stopped. The current consumption Ia corresponding to the current change amount ΔIa2 can be reduced.

[1-5. effect]
As described above, in the electric work machine 1 of the present embodiment, when the control unit 62 is in the low power operation state, the control unit power supply 64 shifts to the second conversion state, and the control unit power supply 64 is used. Since the first conversion power supply 65 is not used for the voltage conversion, the power consumption of the first conversion power supply 65 can be suppressed. Therefore, when the operating state of the control unit 62 shifts from the control operating state to the low power operating state when the electric work machine 1 is not used, not only the power consumption of the control unit 62 is reduced, but also the first conversion power supply is used. Since the power consumption at 65 can be reduced, the power consumption when the electric work machine 1 is not used can be reduced.

Next, in the electric work machine 1, the power supply 64 for the control unit changes its operating state to the first conversion state when the electric work machine 1 is operated by the user (for example, a pulling operation of the trigger operation unit 9). It is configured to migrate. That is, when the trigger operation unit 9 is operated by the user when the operating state of the control unit power supply 64 is the second conversion state, the control unit power supply 64 is the operating state of the control unit power supply 64. Shifts from the second conversion state to the first conversion state. As a result, since the constant voltage Vcc is supplied to the control unit 62 by at least the first conversion power supply 65, it is possible to receive the supply of the maximum control current ICmax required in the control operation state, and the motor 61 can be controlled. It becomes.

Next, since the electric working machine 1 includes the first backflow current suppressing unit 69, the inflow of the backflow current into the output unit 65b of the first conversion power supply 65 can be suppressed. Therefore, in the electric work machine 1, the current output from the second conversion power supply 71 by the first backflow current suppression unit 69 flows into the output unit 65b of the first conversion power supply 65 via the third branch point P3. Can be suppressed.

Next, since the electric work machine 1 includes the second backflow current suppressing unit 73, the inflow of the backflow current into the output unit 71b of the second conversion power supply 71 can be suppressed. Therefore, in the electric work machine 1, the current output from the first conversion power supply 65 flows into the output unit 71b of the second conversion power supply 71 via the third branch point P3 by the second backflow current suppression unit 73. Can be suppressed.

Next, in the electric work machine 1, the output voltage of the first conversion power supply 65 (constant voltage Vcc = 5 [V]) and the output voltage of the second conversion power supply 71 (constant voltage Vcc = 5 [V]) are the same. It is a voltage value, and further, a switching unit 69b is provided in parallel with the diode 69a in the first backflow current suppression unit 69, and the second backflow current suppression unit 73 is composed of a diode. Therefore, when the control unit 62 is in the control operation state, the first conversion power supply 65 and the second conversion power supply 71 both output voltage, and the switching unit 69b is on, the first conversion power supply 65 is used. The voltage output to the voltage supply line 81 and the voltage output from the second conversion power supply 71 to the constant voltage supply line 81 via the second backflow current suppression unit 73 are different values. Specifically, when the control unit 62 is in the control operation state, the voltage output from the first conversion power supply 65 to the constant voltage supply line 81 becomes the constant voltage Vcc, whereas the second conversion power supply 71 to the second 2. The voltage output to the constant voltage supply line 81 via the backflow current suppression unit 73 is a voltage dropped from the constant voltage Vcc by the forward voltage (Vf) of the diode. Therefore, when the control unit 62 is in the control operation state, only the voltage output from the first conversion power supply 65 is supplied to the control unit 62, so that the maximum current consumption of the control unit 62 cannot be supplied. It is possible to suppress the state of being supplied from the second conversion power supply 71.

Next, in the electric work machine 1, the operation state determination unit 75 is configured to be able to receive the first state notification signal Smo1 and the second state notification signal Smo2. The operation state determination unit 75 determines that the operation state of the control unit 62 is the control operation state when the first state notification signal Smo1 is received, and controls when the second state notification signal Smo2 is received. It is determined that the operating state of unit 62 is a low power operating state. That is, the operation state determination unit 75 can determine the operation state of the control unit 62 based on the first state notification signal Smo1 and the second state notification signal Smo2.

[1-6. Correspondence of wording]
Here, the correspondence between words will be described.
The electric work machine 1 corresponds to an example of an electric work machine, the motor 61 corresponds to an example of a drive unit, and the battery pack 100 corresponds to an example of a power source.

The control unit 62 and the motor drive unit 63 correspond to an example of the control unit, the power supply 64 for the control unit corresponds to an example of the power supply for the control unit, and the first conversion power supply 65 corresponds to an example of the first conversion power supply. The 2 conversion power supply 71 corresponds to an example of the second conversion power supply, and the operation state determination unit 75 corresponds to an example of the operation state determination unit.

The first backflow current suppression unit 69 corresponds to an example of the first backflow current suppression unit, the second backflow current suppression unit 73 corresponds to an example of the second backflow current suppression unit, and the first current path LC1 corresponds to the first current path. The second current path LC2 corresponds to an example of the second current path.

[2. Second Embodiment]
As the second embodiment, the second electric work machine 21 configured by replacing some of the components in the electric work machine 1 of the above embodiment (hereinafter, also referred to as the first embodiment) will be described.

As shown in FIG. 4, in the second electric work machine 21, among the electric work machines 1, the control unit power supply 64, the motor 61, and the motor drive unit 63 are the second control unit power supply 91, the brushless motor 97, respectively. It is configured by being replaced by a motor driver 99.

[2-1. Power supply for the second control unit]
The second control unit power supply 91 is configured to include a third conversion power supply 93 and a fourth conversion power supply 95 in place of the first conversion power supply 65 among the control unit power supplies 64.

The third conversion power supply 93 includes a DC-DC converter that converts a DC voltage into a voltage and outputs the voltage. The third conversion power supply 93 converts the battery voltage VB input to the input unit 93a into a voltage, and outputs the second constant voltage Vdd after the voltage conversion from the output unit 93b. The third conversion power supply 93 outputs 15 [V] as the second constant voltage Vdd. The third conversion power supply 93 has a maximum output current of 150 mA for voltage conversion.

The fourth conversion power supply 95 includes a series regulator that converts a DC voltage into a voltage and outputs the voltage. The fourth conversion power supply 95 converts the second constant voltage Vdd input to the input unit 95a into a voltage, and outputs the constant voltage Vcc after the voltage conversion from the output unit 95b. The fourth conversion power supply 95 outputs 5 [V] as a constant voltage Vcc. The fourth conversion power supply 95 has a maximum output current of 100 mA for voltage conversion.

That is, the power supply 91 for the second control unit is configured to be able to convert the battery voltage VB into the constant voltage Vcc by using the third conversion power supply 93 and the fourth conversion power supply 95. The constant voltage Vcc is supplied to each part (control unit 62, etc.) of the second electric work machine 21 via the constant voltage supply line 81. The power consumption required for voltage conversion in the third conversion power supply 93 and the fourth conversion power supply 95 is the power consumption corresponding to the current consumption on the order of mA.

The second control unit power supply 91 having such a configuration receives the third conversion power supply 93 and the fourth conversion power supply 95 when the energization command signal Sc1 indicating that the operation state is in the control operation state is input from the operation state determination unit 75. By outputting the constant voltage Vcc using the second conversion power supply 71 and outputting the constant voltage Vcc using the second conversion power supply 71, the control unit 62 is supplied with the power for the control unit (hereinafter, also referred to as the first conversion state). Transition.

Further, when the energization command signal Sc1 indicating that the second control unit power supply 91 is in the low power operation state is input from the operation state determination unit 75, the voltage conversion by the third conversion power supply 93 and the fourth conversion power supply 95 is performed. Is stopped, and the constant voltage Vcc is output using the second conversion power supply 71, thereby shifting to a state of supplying power for the control unit to the control unit 62 (hereinafter, also referred to as a second conversion state).

The brushless motor 97 is configured to include a three-phase brushless motor. The motor driver 99 converts the direct current from the battery pack 100 into a three-phase AC current (U-phase drive current, V-phase drive current, and W-phase drive current) for driving the brushless motor 97, and the brushless motor 97. Output to. The motor driver 99 drives the brushless motor 97 in accordance with the motor drive command Smd input from the control unit 62.

[2-2. Change status of current consumption due to switching of operating state in the control unit]
Next, the change state of the current consumption Ia in the power supply 91 for the second control unit due to the switching of the operating state in the control unit 62 will be described with reference to FIG.

FIG. 5 shows the switching of the operating state of the control unit 62 and the change status of the current consumption Ia with the passage of time, with the time point when the pulling operation of the trigger operation unit 9 by the user is completed as time t0.
During the period from the time t0 to the time t11 when the sleep determination time Ts has elapsed, if the state in which the trigger operation unit 9 is not pulled by the user continues, the control unit 62 controls the operation state. The process for shifting to the low power operating state (operating state switching process) is started.

When the operation state switching process is started, the control unit 62 first executes a process of sequentially stopping the power supply to various devices and circuits provided in the second electric work machine 21. Along with this, the current consumption Ia gradually decreases from the tenth current consumption Ia10 (time t11 to t12), and the current corresponding to the current consumption amount (first current change amount ΔIa11) in various devices before stopping is increased. The current consumption Ia at this time is reduced to the eleventh current consumption Ia11.

Next, the control unit 62 executes a process of outputting a state notification signal Smo indicating that it is in a low power operation state as one step in the operation state switching process (time t12). As a result, the voltage conversion by the third conversion power supply 93 and the fourth conversion power supply 95 is stopped, and the current consumption required for the voltage conversion by the third conversion power supply 93 and the fourth conversion power supply 95 (second current change amount ΔIa12). The current corresponding to is reduced, and the current consumption Ia at this time is reduced to the twelfth current consumption Ia12.

Next, the control unit 62 executes a process of shifting the control unit 62 itself to the low power operation state (sleep mode) as one step in the operation state switching process (time t13). As a result, the current corresponding to the difference between the current consumption in the control operation state and the current consumption in the low power operation state in the control unit 62 is reduced, and the current corresponding to the current consumption (third current change amount ΔIa13) is reduced. The current consumption Ia at this time decreases to the thirteenth current consumption Ia13.

By executing these, the control unit 62 maintains the low power operation state until the operation state switching process is completed and the trigger operation unit 9 is pulled by the user.
After that, when the trigger operation unit 9 is pulled by the user (time t14), the trigger signal Str is input to the control unit 62. As a result, the control unit 62 itself shifts from the low power operation state (sleep mode) to the control operation state (wakeup). Then, the wake-up control unit 62 starts the operation state switching process for shifting the operation state from the low power operation state to the control operation state. Further, the trigger signal Str from the trigger operation unit 9 is also input to the operation state determination unit 75, and the energization command signal Sc1 from the operation state determination unit 75 is input to the power supply 91 for the second control unit. Voltage conversion by the 3 conversion power supply 93 and the 4th conversion power supply 95 is started. Therefore, the current consumption Ia gradually increases to the eleventh current consumption Ia11 (time t14 to t15) as the control unit 62 wakes up and the voltage conversion operations of the third conversion power supply 93 and the fourth conversion power supply 95 occur.

Next, as one step in the operation state switching process, the control unit 62 executes a process of outputting a state notification signal Smo (first state notification signal Smo1) indicating that the control operation state is in effect (time t15). As a result, the constant voltage Vcc output from the output unit 95b of the fourth conversion power supply 95 is supplied to the constant voltage supply line 81 without a voltage drop.

Next, the control unit 62 executes a process of sequentially starting power supply to various devices and circuits provided in the second electric work machine 21 as one step in the operation state switching process (time t16). Along with this, the current consumption Ia increases to the tenth current consumption Ia10.

In this way, when the operating state of the control unit 62 shifts to the low power operating state, the second electric working machine 21 stops the voltage conversion by the third conversion power supply 93 and the fourth conversion power supply 95. Therefore, the current consumption Ia corresponding to the second current change amount ΔIa12 can be reduced.

[2-3. effect]
As described above, in the second electric work machine 21 of the second embodiment, when the control unit 62 is in the low power operation state, the power supply 91 for the second control unit shifts to the second conversion state. Since the third conversion power supply 93 and the fourth conversion power supply 95 are not used for the voltage conversion in the power supply 91 for the second control unit, the power consumption in the third conversion power supply 93 and the fourth conversion power supply 95 can be suppressed. Therefore, when the operating state of the control unit 62 shifts from the control operating state to the low power operating state when the second electric working machine 21 is not used, not only the power consumption of the control unit 62 is reduced, but also the third power consumption is reduced. Since the power consumption of the conversion power supply 93 and the fourth conversion power supply 95 can be reduced, the power consumption of the second electric work machine 21 when not in use can be reduced.

[2-4. Correspondence of wording]
Here, the correspondence between words will be described.
The second electric work machine 21 corresponds to an example of an electric work machine, the control unit 62 and the motor driver 99 correspond to an example of the control unit, the brushless motor 97 corresponds to an example of the drive unit, and the power supply for the second control unit. 91 corresponds to an example of the power supply for the control unit, and the third conversion power supply 93 and the fourth conversion power supply 95 correspond to an example of the first conversion power supply.

[3. Third Embodiment]
As a third embodiment, the third electric work machine 23 configured by replacing some of the components in the second electric work machine 21 of the second embodiment will be described.

As shown in FIG. 6, the third electric work machine 23 is configured such that the power supply 91 for the second control unit of the second electric work machine 21 is replaced with the power supply 111 for the third control unit.
[3-1. Power supply for the third control unit]
The power supply 111 for the third control unit converts the battery voltage VB from the battery pack 100 into a voltage, and outputs the constant voltage Vcc after the voltage conversion to the constant voltage supply line 81. The constant voltage Vcc is supplied to each part (control unit 62, etc.) of the third electric work machine 23 via the constant voltage supply line 81. In the third embodiment, the constant voltage Vcc is 5 [V]. The electric power supplied from the power supply 111 for the third control unit via the constant voltage supply line 81 is used, for example, as the operating power for the control unit 62 and the like.

The third control unit power supply 111 includes a third conversion power supply 93, a first switching unit 67, a backflow current suppression unit 113, a fourth conversion power supply 95, a bypass current determination unit 115, a third current path LC3, and a bypass current path LC4. It is provided with a common current path LC5.

Of these, the third conversion power supply 93, the first switching unit 67, and the fourth conversion power supply 95 have the same configurations as the third conversion power supply 93, the first switching unit 67, and the fourth conversion power supply 95 of the second embodiment, respectively. Is.

The third current path LC3 is a part of the current path from the battery pack 100 to the control unit 62, and is a current path provided with the third conversion power supply 93. The bypass current path LC4 is a current path connected in parallel to the third current path LC3. The common current path LC5 is a current path that is directly connected to each of the third current path LC3 and the bypass current path LC4 and is provided with the fourth conversion power supply 95.

The first end of the third current path LC3 and the first end of the bypass current path LC4 are connected to the fourth branch point P4 and also to the voltage conversion path LC, respectively. The second end of the third current path LC3 and the second end of the bypass current path LC4 are each connected to the fifth branch point P5 and also to the first end of the common current path LC5. The second end of the common current path LC5 is connected to the constant voltage supply line 81.

The backflow current suppression unit 113 is provided between the third conversion power supply 93 and the fifth branch point P5 in the third current path LC3. The backflow current suppression unit 113 includes a diode connected in series with the third current path LC3. This diode is arranged so as to allow energization from the third conversion power source 93 to the fifth branch point P5 and suppress energization from the fifth branch point P5 to the third conversion power source 93. Therefore, the backflow current suppression unit 113 allows the output of the constant voltage Vcc from the output unit 93b of the third conversion power supply 93 to the fifth branch point P5, and the output from the fifth branch point P5 to the third conversion power supply 93. It is configured to suppress the inflow of the backflow current into the portion 93b.

The bypass current determination unit 115 is provided in the bypass current path LC4. The bypass current determination unit 115 includes a detection resistor 117 and a current determination unit 119. The detection resistor 117 includes a resistance element connected in series with the bypass current path LC4, and is configured to be able to output a detection voltage corresponding to the bypass current Ibp flowing through the bypass current path LC4. The current determination unit 119 includes an FET, and is configured to output a current notification signal Sia corresponding to the bypass current Ibp to the operation state determination unit 75 based on the voltage across the detection resistor 117. There is.

When the first switching unit 67 is off and the operating state of the control unit 62 is the control operating state, the power consumption of the control unit 62 or the like via the constant voltage supply line 81 becomes large, and the bypass is performed. Since the current Ibp becomes large, the potential of the input portion 95a of the fourth conversion power supply 95 becomes low. Further, when the first switching unit 67 is off and the operating state of the control unit 62 is a low power operating state, the power consumption of the control unit 62 or the like via the constant voltage supply line 81 becomes small. Since the bypass current Ibp becomes small, the potential of the input unit 95a of the fourth conversion power supply 95 becomes high.

The current determination unit 119 is configured to output a current notification signal Sia corresponding to the bypass current Ibp. When the bypass current Ibp is larger than the predetermined operation reference value Is (for example, 5 [mA]), the current determination unit 119 turns on the FET and notifies the current that the potential is the same as the battery voltage VB. The signal Sia (hereinafter, also referred to as the first current notification signal Sia1) is output. When the bypass current Ibp is equal to or less than the operation reference value Is, the current determination unit 119 turns off the FET and the current notification signal Sia whose potential is lower than the battery voltage VB (hereinafter, also referred to as the second current notification signal Sia2). Is output.

That is, the bypass current determination unit 115 determines whether the operation state of the control unit 62 is the control operation state or the low power operation state based on the comparison result between the bypass current Ibp and the operation reference value Is. It is configured.

When the current determination unit 119 determines that the operation state of the control unit 62 is the control operation state, the current determination unit 119 outputs the first current notification signal Sia1 to the operation state determination unit 75. As a result, the operation state determination unit 75 outputs the energization command signal Sc1 indicating that the control operation state is in effect to the first switching unit 67, and the voltage conversion by the third conversion power supply 93 is executed. At this time, the third control unit power supply 111 is in a state of supplying the control unit power to the control unit 62 by outputting a constant voltage Vcc using the third conversion power supply 93 and the fourth conversion power supply 95 (hereinafter, It shifts to the first conversion state).

When the current determination unit 119 determines that the operation state of the control unit 62 is a low power operation state, the current determination unit 119 outputs a second current notification signal Sia2 to the operation state determination unit 75. As a result, the operation state determination unit 75 outputs the energization command signal Sc1 indicating that the operation state is in the low power operation state to the first switching unit 67, and the voltage conversion by the third conversion power supply 93 is stopped. At this time, the third control unit power supply 111 supplies the control unit power to the control unit 62 by outputting a constant voltage Vcc using the fourth conversion power supply 95 (hereinafter, also referred to as a second conversion state). ).

[3-2. Change status of current consumption due to switching of operating state in the control unit]
Next, the change state of the current consumption Ia in the power supply 111 for the third control unit due to the switching of the operating state in the control unit 62 will be described with reference to FIG. 7.

FIG. 7 shows the switching of the operating state of the control unit 62 and the change status of the current consumption Ia with the passage of time, with the time point when the pulling operation of the trigger operation unit 9 by the user is completed is set to time t0.
During the period from the time t0 to the time t21 when the sleep determination time Ts has elapsed, if the state in which the trigger operation unit 9 is not pulled by the user continues, the control unit 62 controls the operation state. The process for shifting to the low power operating state (operating state switching process) is started.

When the operation state switching process is started, the control unit 62 first executes a process of sequentially stopping the power supply to various devices and circuits provided in the third electric work machine 23. Along with this, the current consumption Ia gradually decreases from the 20th current consumption Ia20 (time t21 to t22), and the current corresponding to the current consumption (first current change amount ΔIa21) in various devices before stopping is increased. The current consumption Ia at this time is reduced to the 21st current consumption Ia21.

Next, the control unit 62 executes a process of shifting the control unit 62 itself to the low power operation state (sleep mode) as one step in the operation state switching process (time t22). As a result, the current corresponding to the difference between the current consumption in the control operation state and the current consumption in the low power operation state in the control unit 62 is reduced, and the current corresponding to the current consumption (second current change amount ΔIa22) is reduced. The current consumption Ia at this time decreases to the 22nd current consumption Ia22. The second current change amount ΔIa22 corresponds to the third current change amount ΔIa3 of the first embodiment and the third current change amount ΔIa13 of the second embodiment.

After that, as the current consumption of the control unit 62 decreases, when the bypass current determination unit 115 determines that the operation state of the control unit 62 is a low power operation state, the operation state determination unit 75 to the first switching unit 67 On the other hand, the energization command signal Sc1 indicating that the power is in the low power operation state is output, and the voltage conversion by the third conversion power supply 93 is stopped. As a result, the current corresponding to the current consumption (third current change amount ΔIa23) required for voltage conversion in the third conversion power supply 93 is reduced, and the current consumption Ia at this time is reduced to the 23rd current consumption Ia23. The third current change amount ΔIa23 corresponds to the second current change amount ΔIa2 of the first embodiment and the second current change amount ΔIa12 of the second embodiment.

By executing these, the control unit 62 maintains the low power operation state until the operation state switching process is completed and the trigger operation unit 9 is pulled by the user.
After that, when the trigger operation unit 9 is pulled by the user (time t24), the trigger signal Str is input to the control unit 62. As a result, the control unit 62 itself shifts from the low power operation state (sleep mode) to the control operation state (wakeup). Then, the wake-up control unit 62 starts the operation state switching process for shifting the operation state from the low power operation state to the control operation state. Further, the trigger signal Str from the trigger operation unit 9 is also input to the operation state determination unit 75, and the energization command signal Sc1 from the operation state determination unit 75 is input to the power supply 111 for the third control unit. The voltage conversion by the 3 conversion power source 93 is started. Therefore, the current consumption Ia gradually increases to the 21st current consumption Ia21 (time t24 to t25) as the control unit 62 wakes up and the voltage conversion operation of the third conversion power supply 93 occurs. The current consumption Ia is increased by the second current change amount ΔIa22 from the 23rd current consumption Ia23 to become the 24th current consumption Ia24 due to the wakeup of the control unit 62 (time t24). After that, the current consumption Ia is increased by the third current change amount ΔIa23 by the voltage conversion operation of the third conversion power supply 93 to become the 21st current consumption Ia21 (time t25).

At this time, as the current consumption in the control unit 62 increases, when the bypass current determination unit 115 determines that the operation state of the control unit 62 is the control operation state, the operation state determination unit 75 shifts to the first switching unit 67. On the other hand, the energization command signal Sc1 indicating that the control operation state is in effect is output. At this time, the voltage conversion by the third conversion power supply 93 has already been executed based on the trigger signal Str from the trigger operation unit 9, but the sleep determination is made even when the operation of the trigger operation unit 9 by the user is completed. Until the time Ts elapses, the control operation state of the control unit 62 is maintained, and the voltage conversion by the third conversion power supply 93 is continued.

Next, the control unit 62 executes a process of sequentially starting power supply to various devices and circuits provided in the third electric work machine 23 as one step in the operation state switching process (time t26). Along with this, the current consumption Ia increases to the 20th current consumption Ia20.

In this way, when the operating state of the control unit 62 shifts to the low power operating state, the third electric work machine 23 uses the third conversion power supply 93 based on the determination result of the bypass current determination unit 115. By stopping the voltage conversion of, the current consumption Ia corresponding to the third current change amount ΔIa23 can be reduced.

[3-3. effect]
As described above, in the third electric work machine 23 of the third embodiment, when the control unit 62 is in the low power operation state, the third control unit is based on the determination result of the bypass current determination unit 115. Since the power supply 111 shifts to the second conversion state and the third conversion power supply 93 is not used for voltage conversion in the power supply 111 for the third control unit, the power consumption in the third conversion power supply 93 can be suppressed. Therefore, when the operating state of the control unit 62 shifts from the control operating state to the low power operating state when the third electric working machine 23 is not used, not only the power consumption of the control unit 62 is reduced, but also the third power consumption is reduced. Since the power consumption of the conversion power supply 93 can be reduced, the power consumption of the third electric work machine 23 when not in use can be reduced.

[3-4. Correspondence of wording]
Here, the correspondence between words will be described.
The third electric work machine 23 corresponds to an example of the electric work machine, the control unit 62 and the motor driver 99 correspond to an example of the control unit, the brushless motor 97 corresponds to an example of the drive unit, and the power supply for the third control unit. 111 corresponds to an example of the power supply for the control unit, the third conversion power supply 93 corresponds to an example of the first conversion power supply, and the fourth conversion power supply 95 corresponds to an example of the second conversion power supply.

The operation state determination unit 75 and the bypass current determination unit 115 correspond to an example of the operation state determination unit, the third current path LC3 corresponds to an example of the third current path, and the bypass current path LC4 corresponds to an example of the bypass current path. The common current path LC5 corresponds to an example of the common current path, the second constant voltage Vdd corresponds to an example of the intermediate power supply voltage, and the operating reference value Is corresponds to an example of the operating reference value.

[4. Fourth Embodiment]
As the fourth embodiment, the fourth electric work machine 25 configured by replacing some of the components in the third electric work machine 23 of the third embodiment will be described.

As shown in FIG. 8, in the fourth electric work machine 25, the power supply 111 for the third control unit and the bypass current determination unit 115 of the third electric work machine 23 have the power supply 121 for the fourth control unit and the second power supply 121, respectively. It is configured by being replaced by the bypass current determination unit 131.

[4-1. Power supply for the 4th control unit]
The fourth control unit power supply 121 converts the battery voltage VB from the battery pack 100 into a voltage, and outputs the constant voltage Vcc after the voltage conversion to the constant voltage supply line 81. The constant voltage Vcc is supplied to each part (control unit 62, etc.) of the fourth electric working machine 25 via the constant voltage supply line 81. In the fourth embodiment, the constant voltage Vcc is 5 [V]. The electric power supplied from the fourth control unit power supply 121 via the constant voltage supply line 81 is used as, for example, operating power for the control unit 62 and the like.

The fourth control unit power supply 121 is common to the third conversion power supply 93, the first switching unit 67, the backflow current suppression unit 113, the fourth conversion power supply 95, the limiting resistance unit 123, the third current path LC3, and the bypass current path LC4. It is provided with a current path LC5.

Of these, the third conversion power supply 93, the first switching unit 67, the fourth conversion power supply 95, the third current path LC3, the bypass current path LC4, and the common current path LC5 are the third conversion power supply 93 of the second embodiment, respectively. , The first switching unit 67, the fourth conversion power supply 95, the third current path LC3, the bypass current path LC4, and the common current path LC5 have the same configurations.

The limiting resistor unit 123 is connected in series to the bypass current path LC4. The limiting resistance unit 123 is configured to include a resistance element, and suppresses the bypass current Ibp flowing through the bypass current path LC4 from becoming excessive.

The second bypass current determination unit 131 includes a hysteresis comparator 133, a resistance unit 135, a resistance unit 134, and a reference voltage unit 136. The second bypass current determination unit 131 is electrically connected to the fifth branch point P5 via the sixth path LC6, detects the potential of the input unit 95a of the fourth conversion power supply 95, and sets the bypass current Ibp. It is configured to be detectable. The second bypass current determination unit 131 is configured to output a current notification signal Sia corresponding to the bypass current Ibp to the operation state determination unit 75.

As described in the third embodiment, when the first switching unit 67 is off and the operating state of the control unit 62 is the control operating state, the control unit 62 or the like via the constant voltage supply line 81 or the like. Since the power consumption in the above is large and the bypass current Ibp is large, the potential of the input unit 95a of the fourth conversion power supply 95 is low. Further, when the first switching unit 67 is off and the operating state of the control unit 62 is a low power operating state, the power consumption of the control unit 62 or the like via the constant voltage supply line 81 becomes small. Since the bypass current Ibp becomes small, the potential of the input unit 95a of the fourth conversion power supply 95 becomes high.

In the second bypass current determination unit 131, the bypass current Ibp becomes larger than the predetermined operation reference value Is (for example, 5 [mA]), and the fifth branch point P5 (input unit 95a of the fourth conversion power supply 95). When the potential of is lower than the determination voltage Vth, the current notification signal Sia (hereinafter, also referred to as the first current notification signal Sia1) having the same potential as the battery voltage VB is output. In the second bypass current determination unit 131, when the bypass current Ibp is equal to or less than the operation reference value Is and the potential of the fifth branch point P5 (input unit 95a of the fourth conversion power supply 95) exceeds the determination voltage Vth, the potential becomes the battery voltage. It outputs a current notification signal Sia lower than VB (hereinafter, also referred to as a second current notification signal Sia2).

That is, the second bypass current determination unit 131 determines whether the operation state of the control unit 62 is the control operation state or the low power operation state based on the comparison result between the bypass current Ibp and the operation reference value Is. It is configured as follows.

The second bypass current determination unit 131 includes a hysteresis comparator 133, and has a determination voltage Vth (hereinafter, also referred to as a first determination voltage Vth1) used for output determination of the first current notification signal Sia1 and a second current notification. The determination voltage Vth (hereinafter, also referred to as the second determination voltage Vth2) used for the output determination of the signal Sia2 can be set to different values.

For example, the output voltage of the reference voltage unit 136 is set to the determination voltage Vth (= Vdd + ΔVa = 17 [V]) obtained by adding a predetermined adjustment voltage ΔVa (= 2 [V]) to the second constant voltage Vdd, and the hysteresis comparator is set. When the hysteresis width according to 133 is set to 1 [V], the first determination voltage Vth1 becomes 16 [V] and the second determination voltage Vth2 becomes 18 [V].

In this case, when the potential of the fifth branch point P5 (input unit 95a of the fourth conversion power supply 95) falls below 16 [V], the second bypass current determination unit 131 changes the operating state of the control unit 62 to the control operating state. It is determined that there is, and the output of the first current notification signal Sia1 is started. After that, while the potential of the fifth branch point P5 is 18 [V] or less, the second bypass current determination unit 131 determines that the operation state of the control unit 62 is the control operation state, and the first current notification signal. The output of Sia1 is continued. After that, when the potential of the fifth branch point P5 exceeds 18 [V], the second bypass current determination unit 131 determines that the operation state of the control unit 62 is a low power operation state, and determines that the second current notification signal. The output of Sia2 is started. After that, while the potential of the fifth branch point P5 is 16 [V] or more, the second bypass current determination unit 131 determines that the operation state of the control unit 62 is a low power operation state, and notifies the second current. The output of the signal Sia2 is continued. After that, when the potential of the fifth branch point P5 falls below 16 [V], the second bypass current determination unit 131 starts outputting the first current notification signal Sia1.

When the second bypass current determination unit 131 determines that the operation state of the control unit 62 is the control operation state, the second bypass current determination unit 131 outputs the first current notification signal Sia1 to the operation state determination unit 75. As a result, the operation state determination unit 75 outputs the energization command signal Sc1 indicating that the control operation state is in effect to the first switching unit 67, and the voltage conversion by the third conversion power supply 93 is executed. At this time, the fourth control unit power supply 121 is in a state of supplying the control unit power to the control unit 62 by outputting a constant voltage Vcc using the third conversion power supply 93 and the fourth conversion power supply 95 (hereinafter, It shifts to the first conversion state).

When the second bypass current determination unit 131 determines that the operation state of the control unit 62 is a low power operation state, the second bypass current determination unit 131 outputs the second current notification signal Sia2 to the operation state determination unit 75. As a result, the operation state determination unit 75 outputs the energization command signal Sc1 indicating that the operation state is in the low power operation state to the first switching unit 67, and the voltage conversion by the third conversion power supply 93 is stopped. At this time, the fourth control unit power supply 121 supplies the control unit power to the control unit 62 by outputting a constant voltage Vcc using the fourth conversion power supply 95 (hereinafter, also referred to as a second conversion state). ).

[4-2. Change status of current consumption due to switching of operating state in the control unit]
Next, the change state of the current consumption Ia in the power supply 121 for the fourth control unit due to the switching of the operating state in the control unit 62 will be described with reference to FIG.

FIG. 9 shows the switching of the operating state of the control unit 62 and the change status of the current consumption Ia with the passage of time, with the time point when the pulling operation of the trigger operation unit 9 by the user is completed as time t0.
During the period from the time t0 to the time t31 when the sleep determination time Ts has elapsed, if the state in which the trigger operation unit 9 is not pulled by the user continues, the control unit 62 controls the operation state. The process for shifting to the low power operating state (operating state switching process) is started.

When the operation state switching process is started, the control unit 62 first executes a process of sequentially stopping the power supply to various devices and circuits provided in the fourth electric work machine 25. Along with this, the current consumption Ia gradually decreases from the 30th current consumption Ia30 (time t31 to t32), and the current corresponding to the current consumption (first current change amount ΔIa31) in various devices before stopping is increased. The current consumption Ia at this time is reduced to the 31st current consumption Ia31.

Next, the control unit 62 executes a process of shifting the control unit 62 itself to the low power operation state (sleep mode) as one step in the operation state switching process (time t32). As a result, the current corresponding to the difference between the current consumption in the control operation state and the current consumption in the low power operation state in the control unit 62 is reduced, and the current corresponding to the current consumption (second current change amount ΔIa32) is reduced. The current consumption Ia at this time is reduced to the 32nd current consumption Ia32.

After that, as the current consumption in the control unit 62 decreases, when the second bypass current determination unit 131 determines that the operation state of the control unit 62 is a low power operation state, the operation state determination unit 75 first switches. An energization command signal Sc1 indicating that the power is in the low power operation state is output to the unit 67, and the voltage conversion by the third conversion power supply 93 is stopped. As a result, the current corresponding to the current consumption (third current change amount ΔIa33) required for voltage conversion in the third conversion power supply 93 is reduced, and the current consumption Ia at this time is reduced to the 33rd current consumption Ia33.

By executing these, the control unit 62 maintains the low power operation state until the operation state switching process is completed and the trigger operation unit 9 is pulled by the user.
After that, when the trigger operation unit 9 is pulled by the user (time t34), the trigger signal Str is input to the control unit 62. As a result, the control unit 62 itself shifts from the low power operation state (sleep mode) to the control operation state (wakeup). Then, the wake-up control unit 62 starts the operation state switching process for shifting the operation state from the low power operation state to the control operation state. Further, the trigger signal Str from the trigger operation unit 9 is also input to the operation state determination unit 75, and the energization command signal Sc1 from the operation state determination unit 75 is input to the power supply 121 for the fourth control unit. The voltage conversion by the 3 conversion power source 93 is started. Therefore, with the wake-up of the control unit 62 and the voltage conversion operation of the third conversion power supply 93, the current consumption Ia gradually increases to the 31st current consumption Ia31 (time t34 to t35). The current consumption Ia is increased by the second current change amount ΔIa32 from the 33rd current consumption Ia33 to become the 34th current consumption Ia34 due to the wakeup of the control unit 62 (time t34). After that, the current consumption Ia is increased by the third current change amount ΔIa33 by the voltage conversion operation of the third conversion power supply 93 to become the 31st current consumption Ia31 (time t35).

At this time, when the second bypass current determination unit 131 determines that the operation state of the control unit 62 is the control operation state as the current consumption in the control unit 62 increases, the operation state determination unit 75 to the first switching unit An energization command signal Sc1 indicating that the control operation state is in effect is output to 67. At this time, the voltage conversion by the third conversion power supply 93 has already been executed based on the trigger signal Str from the trigger operation unit 9, but the sleep determination is made even when the operation of the trigger operation unit 9 by the user is completed. Until the time Ts elapses, the control operation state of the control unit 62 is maintained, and the voltage conversion by the third conversion power supply 93 is continued.

Next, the control unit 62 executes a process of sequentially starting power supply to various devices and circuits provided in the fourth electric work machine 25 as one step in the operation state switching process (time t36). Along with this, the current consumption Ia increases to the 30th current consumption Ia30.

As described above, when the operating state of the control unit 62 shifts to the low power operating state, the fourth electric work machine 25 uses the third conversion power supply based on the determination result of the second bypass current determination unit 131. By stopping the voltage conversion at 93, the current consumption Ia corresponding to the third current change amount ΔIa33 can be reduced.

[4-3. effect]
As described above, in the fourth electric work machine 25 of the fourth embodiment, when the control unit 62 is in the low power operation state, the fourth is based on the determination result of the second bypass current determination unit 131. Since the control unit power supply 121 shifts to the second conversion state and the third conversion power supply 93 is not used for voltage conversion in the fourth control unit power supply 121, the power consumption in the third conversion power supply 93 can be suppressed. Therefore, when the operating state of the control unit 62 shifts from the control operating state to the low power operating state when the fourth electric working machine 25 is not used, not only the power consumption of the control unit 62 is reduced, but also the third power consumption is reduced. Since the power consumption of the conversion power supply 93 can be reduced, the power consumption of the fourth electric work machine 25 when not in use can be reduced.

[4-4. Correspondence of wording]
Here, the correspondence between words will be described.
The fourth electric work machine 25 corresponds to an example of an electric work machine, the power supply 121 for the fourth control unit corresponds to an example of the power supply for the control unit, and the operation state determination unit 75 and the second bypass current determination unit 131 correspond to the operation state. It corresponds to an example of the judgment unit.

[5. Fifth Embodiment]
As a fifth embodiment, the fifth electric work machine 27 configured by changing some components in the second electric work machine 21 of the second embodiment will be described.

As shown in FIG. 10, in the fifth electric work machine 27, among the second electric work machines 21, the power supply 91 for the second control unit is replaced with the power supply 141 for the fifth control unit, and the battery pack 100 is used as a plurality of output power supplies. It is configured by replacing it with 102.

The plurality of output power supplies 102 include a plurality of battery packs (first battery pack 103, second battery pack 104), a plurality of voltage output units (first voltage output unit 102a, second voltage output unit 102b), and a reference electrode 102c. And have.

The first battery pack 103 and the second battery pack 104 are connected in series. Each of the first battery pack 103 and the second battery pack 104 includes a secondary battery (not shown) capable of being repeatedly charged and discharged. The output voltage of the first battery pack 103 is 36 [V]. The output voltage of the second battery pack 104 is 36 [V].

The first voltage output unit 102a is connected to the positive electrode of the second battery pack 104. The second voltage output unit 102b is connected to the positive electrode of the first battery pack 103 and the negative electrode of the second battery pack 104, respectively. The reference electrode 102c is connected to the negative electrode of the first battery pack 103.

The plurality of output power supplies 102 are configured such that a plurality of voltage output units (first voltage output unit 102a, second voltage output unit 102b) each output different voltages with reference to the reference electrode 102c. The plurality of output power supplies 102 output the first battery voltage VB1 (VB1 = 72 [V]) from the first voltage output unit 102a, and the second battery voltage VB2 (VB2 = 36 [V]) from the second voltage output unit 102b. Is output.

The first battery pack 103 outputs the first cutoff command signal Sb1 when an abnormal state such as a drop in output voltage occurs. The second battery pack 104 outputs the second cutoff command signal Sb2 when an abnormal state such as a drop in the output voltage occurs.

[5-1. Power supply for 5th control unit]
The fifth control unit power supply 141 converts any one of the first battery voltage VB1 and the second battery voltage VB2 from the plurality of output power supplies 102 into a voltage, and the constant voltage Vcc (Vcc = 5 [V]] after voltage conversion. ) Is output to the constant voltage supply line 81.

The fifth control unit power supply 141 has a configuration in which the second switching unit 143 and the third switching unit 145 are added to the second control unit power supply 91, and the connection destination of the second current path LC2 is changed. .. In the following description, the differences between the power supply 141 for the fifth control unit and the power supply 91 for the second control unit will be mainly described.

The first end of the second current path LC2 is connected to the second voltage output unit 102b of the plurality of output power supplies 102. The second end of the second current path LC2 is connected to the third branch point P3 and also to the constant voltage supply line 81.

The second switching unit 143 and the third switching unit 145 are provided between the input unit 71a of the second conversion power supply 71 and the second voltage output unit 102b of the plurality of output power supplies 102 in the second current path LC2. .. The second switching unit 143 and the third switching unit 145 are each provided with a switching unit (FET or the like) connected in series with the second current path LC2.

The second switching unit 143 is configured to be able to switch the switching unit to an energized state (ON state) or a non-energized state (OFF state) based on the first cutoff command signal Sb1 from the first battery pack 103. The third switching unit 145 is configured to be able to switch the switching unit to an energized state (ON state) or a non-energized state (OFF state) based on the second cutoff command signal Sb2 from the second battery pack 104.

The second switching unit 143 and the third switching unit 145 are configured so that the energization from the second voltage output unit 102b to the second conversion power supply 71 in the second current path LC2 can be switched between an energized state and a non-energized state. .. As a result, the second switching unit 143 and the third switching unit 145 switch the input state of the second battery voltage VB2 to the second conversion power supply 71 based on the first cutoff command signal Sb1 and the second cutoff command signal Sb2. It is configured to be possible.

The third conversion power supply 93 includes a DC-DC converter that converts a DC voltage into a voltage and outputs the voltage. The third conversion power supply 93 converts the first battery voltage VB1 (VB1 = 72 [V]) input to the input unit 93a into a voltage, and outputs the second constant voltage Vdd after the voltage conversion from the output unit 93b. The third conversion power supply 93 outputs 15 [V] as the second constant voltage Vdd. The third conversion power supply 93 has a maximum output current of 150 mA for voltage conversion.

When the energization command signal Sc1 indicating that the fifth control unit is in the control operation state is input from the operation state determination unit 75, the fifth control unit power supply 141 having such a configuration causes the third conversion power supply 93 and the fourth conversion power supply 95. By outputting the constant voltage Vcc using the second conversion power supply 71 and outputting the constant voltage Vcc using the second conversion power supply 71, the control unit 62 is supplied with the power for the control unit (hereinafter, also referred to as the first conversion state). Transition.

Further, when the energization command signal Sc1 indicating that the fifth control unit power supply 141 is in the low power operation state is input from the operation state determination unit 75, the voltage conversion by the third conversion power supply 93 and the fourth conversion power supply 95 is performed. Is stopped, and the constant voltage Vcc is output using the second conversion power supply 71, thereby shifting to a state of supplying power for the control unit to the control unit 62 (hereinafter, also referred to as a second conversion state).

Further, the power supply 141 for the fifth control unit is based on the first cutoff command signal Sb1 from the first battery pack 103 or the second cutoff command signal Sb2 from the second battery pack 104, and the second switching unit 143 or the third. By setting the switching unit 145 to the non-energized state, the input of the second battery voltage VB2 to the second conversion power supply 71 is stopped. That is, when at least one of the first battery pack 103 and the second battery pack 104 becomes abnormal, the fifth control unit power supply 141 stops the input of the second battery voltage VB2 to the second conversion power supply 71. It is configured to stop the output of the constant voltage Vcc by the second conversion power supply 71.

Further, the power supply 141 for the fifth control unit may include a power supply holding circuit 147. The power supply holding circuit 147 is connected between the third conversion power supply 93 and the fourth conversion power supply 95 in the first current path LC1. The power supply holding circuit 147 includes a resistor 147a, a diode 147b, and a capacitor 147c.

The power holding circuit 147 is configured to charge the capacitor 147c via the resistor 147a when charging the capacitor 147c, and discharge the capacitor 147c via the diode 147b when discharging the capacitor 147c. As a result, the power supply holding circuit 147 can quickly discharge the capacitor 147c when the capacitor 147c is discharged, while preventing the second constant voltage Vdd from dropping due to the inrush current at the start of charging the capacitor 147c.

By providing the power holding circuit 147, after the third conversion power supply 93 turns off the output of the second constant voltage Vdd, the second constant voltage Vdd is charged by the electric charge charged in the capacitor 147c of the power holding circuit 147 for a certain period of time. And constant voltage Vcc can be maintained, and the control unit 62 can be driven. Therefore, even if the multiple output power supply 102 is suddenly removed or the output (power supply) from the multiple output power supply 102 is lost due to some abnormality, the second constant voltage Vdd or constant voltage Vcc is discharged due to the discharge of the capacitor 147c. Is maintained, the control unit 62 can appropriately perform the shutdown process. Examples of the shutdown process include a process of writing various history information and various setting states to the non-volatile memory.

[5-2. effect]
As described above, in the fifth electric work machine 27 of the fifth embodiment, when the control unit 62 is in the low power operation state, the power supply 141 for the fifth control unit shifts to the second conversion state, and the fifth is Since the third conversion power supply 93 and the fourth conversion power supply 95 are not used for the voltage conversion in the control unit power supply 141, the power consumption in the third conversion power supply 93 and the fourth conversion power supply 95 can be suppressed. Therefore, when the operating state of the control unit 62 shifts from the control operating state to the low power operating state when the fifth electric working machine 27 is not used, not only the power consumption of the control unit 62 is reduced, but also the third power consumption is reduced. Since the power consumption of the conversion power supply 93 and the fourth conversion power supply 95 can be reduced, the power consumption of the fifth electric work machine 27 when not in use can be reduced.

Further, the fifth electric work machine 27 uses a plurality of output power supplies 102 including a plurality of battery packs as a power source, and can operate with a larger output based on a larger voltage as compared with a configuration using one battery pack. It will be possible. By adopting a configuration in which the plurality of output power supplies 102 include a plurality of battery packs, the maximum voltage that can be output can be increased according to the number of battery packs.

Next, in the fifth electric work machine 27, the second conversion power supply 71 is the first voltage having the largest output voltage among the plurality of voltage output units (first voltage output unit 102a, second voltage output unit 102b). It is connected not to the output unit 102a but to the second voltage output unit 102b having the smallest output voltage. That is, the second conversion power supply 71 may convert the first battery voltage VB1 (VB1 = 72 [V]) output from the first voltage output unit 102a into a constant voltage Vcc (Vcc = 5 [V]). It is configured to convert the second battery voltage VB2 (VB1 = 36 [V]) into a constant voltage Vcc.

As a result, the second conversion power supply 71 can reduce the amount of voltage change in the voltage conversion by the second conversion power supply 71 as compared with the case where the first battery voltage VB1 is converted to a constant voltage Vcc. Therefore, the fifth electric work machine 27 can reduce the power loss due to the voltage conversion in the second conversion power supply 71 as compared with the case where the amount of voltage change is large.

Next, in the fifth electric working machine 27, the "third conversion power supply 93 and the fourth conversion power supply 95" (corresponding to an example of the first conversion power supply) are among the plurality of voltage output units of the plurality of output power supplies 102. It is connected to the first voltage output unit 102a whose output voltage (VB1 = 72 [V]) is larger than the output voltage (VB2 = 36 [V]) of the second voltage output unit 102b to which the second conversion power supply 71 is connected. There is. As a result, the amount of power that can be output from the "third conversion power supply 93 and the fourth conversion power supply 95" becomes larger than the amount of power that can be output from the second conversion power supply 71, and the "third conversion power supply 93 and the fourth conversion power supply 93" The power supply 95 "can supply sufficient power to the control unit 62 as compared with the second conversion power supply 71.

[5-3. Correspondence of wording]
Here, the correspondence between words will be described.
The fifth electric work machine 27 corresponds to an example of the electric work machine, the plurality of output power supplies 102 correspond to an example of the power supply, the fifth control unit power supply 141 corresponds to an example of the power supply for the control unit, and the third conversion power supply. 93 and the fourth conversion power supply 95 correspond to an example of the first conversion power supply.

[6. 6th Embodiment]
As the sixth embodiment, the sixth electric work machine 29 configured by changing some components in the third electric work machine 23 of the third embodiment will be described.

As shown in FIG. 11, in the sixth electric work machine 29, among the third electric work machines 23, the power supply 111 for the third control unit is replaced with the power supply 151 for the sixth control unit, and the battery pack 100 is used as a plurality of output power supplies. It is configured by replacing it with 102.

The plurality of output power supplies 102 have the same configuration as the plurality of output power supplies 102 of the fifth embodiment, and the description thereof will be omitted here.
[6-1. Power supply for 6th control unit]
The sixth control unit power supply 151 converts any one of the first battery voltage VB1 and the second battery voltage VB2 from the plurality of output power supplies 102 into a voltage, and the constant voltage Vcc (Vcc = 5 [V]] after voltage conversion. ) Is output to the constant voltage supply line 81.

The sixth control unit power supply 151 has a configuration in which the fourth switching unit 153 and the fifth switching unit 155 are added to the third control unit power supply 111, and the connection destination of the bypass current path LC4 is changed. In the following description, the differences between the power supply 151 for the sixth control unit and the power supply 111 for the third control unit will be mainly described.

The first end of the bypass current path LC4 is connected to the second voltage output unit 102b of the plurality of output power supplies 102. The second end of the bypass current path LC4 is connected to the fifth branch point P5 and is also connected to the first end of the common current path LC5.

The fourth switching unit 153 and the fifth switching unit 155 are provided between the bypass current determination unit 115 and the second voltage output unit 102b of the plurality of output power supplies 102 in the bypass current path LC4. The fourth switching unit 153 and the fifth switching unit 155 are each provided with a switching unit (FET or the like) connected in series with the bypass current path LC4.

The fourth switching unit 153 is configured to be able to switch the switching unit to an energized state (ON state) or a non-energized state (OFF state) based on the first cutoff command signal Sb1 from the first battery pack 103. The fifth switching unit 155 is configured to be able to switch the switching unit to an energized state (ON state) or a non-energized state (OFF state) based on the second cutoff command signal Sb2 from the second battery pack 104.

The fourth switching unit 153 and the fifth switching unit 155 change the energization state from the second voltage output unit 102b in the bypass current path LC4 toward the fourth conversion power supply 95 via the bypass current determination unit 115 into an energized state or a non-energized state. It is configured to be switchable. As a result, the fourth switching unit 153 and the fifth switching unit 155 are second to the fourth conversion power supply 95 via the bypass current determination unit 115 based on the first cutoff command signal Sb1 and the second cutoff command signal Sb2. The input state of the battery voltage VB2 can be switched.

The third conversion power supply 93 includes a DC-DC converter that converts a DC voltage into a voltage and outputs the voltage. The third conversion power supply 93 converts the first battery voltage VB1 (VB1 = 72 [V]) input to the input unit 93a into a voltage, and outputs the second constant voltage Vdd after the voltage conversion from the output unit 93b. The third conversion power supply 93 outputs 15 [V] as the second constant voltage Vdd. The third conversion power supply 93 has a maximum output current of 150 mA for voltage conversion.

In the sixth control unit power supply 151 having such a configuration, when the first current notification signal Sia1 is output from the current determination unit 119 to the operation state determination unit 75, the operation state determination unit 75 to the first switching unit An energization command signal Sc1 indicating that the control operation state is in effect is output to 67, and voltage conversion by the third conversion power supply 93 is executed. At this time, the power supply 151 for the sixth control unit is controlled by converting the first battery voltage VB1 into a constant voltage Vcc using the third conversion power supply 93 and the fourth conversion power supply 95 and outputting the constant voltage Vcc. The state shifts to the state of supplying the power for the control unit to the unit 62 (hereinafter, also referred to as the first conversion state).

Further, in the power supply 151 for the sixth control unit, when the second current notification signal Sia2 is output from the current determination unit 119 to the operation state determination unit 75, the operation state determination unit 75 to the first switching unit 67. The energization command signal Sc1 indicating that the power is in the low power operation state is output, and the voltage conversion by the third conversion power supply 93 is stopped. At this time, the sixth control unit power supply 151 converts the second battery voltage VB2 into a constant voltage Vcc using the fourth conversion power supply 95, and outputs the constant voltage Vcc to the control unit 62 for the control unit. It shifts to the state of supplying power (hereinafter, also referred to as the second conversion state).

Further, the power supply 151 for the sixth control unit is the fourth switching unit 153 or the fifth switching unit 153 or the fifth based on the first cutoff command signal Sb1 from the first battery pack 103 or the second cutoff command signal Sb2 from the second battery pack 104. By setting the switching unit 155 to the non-energized state, the input of the second battery voltage VB2 to the fourth conversion power supply 95 via the bypass current path LC4 is stopped. That is, when at least one of the first battery pack 103 and the second battery pack 104 becomes abnormal, the power supply 151 for the sixth control unit receives the second battery voltage to the fourth conversion power supply 95 via the bypass current path LC4. By stopping the input of the VB2, the output of the constant voltage Vcc by the fourth conversion power supply 95 via the bypass current path LC4 is stopped.

[6-2. effect]
As described above, in the sixth electric work machine 29 of the sixth embodiment, when the control unit 62 is in the low power operation state, the power supply 151 for the sixth control unit shifts to the second conversion state, and the second is Since the third conversion power supply 93 is not used for voltage conversion in the control unit power supply 151, the power consumption in the third conversion power supply 93 can be suppressed. Therefore, when the operating state of the control unit 62 shifts from the control operating state to the low power operating state when the sixth electric working machine 29 is not used, not only the power consumption of the control unit 62 is reduced, but also the third operation state is reduced. Since the power consumption of the conversion power supply 93 can be reduced, the power consumption of the sixth electric work machine 29 when not in use can be reduced.

Further, the sixth electric work machine 29 uses a plurality of output power supplies 102 including a plurality of battery packs as a power source, and can operate with a larger output based on a larger voltage as compared with a configuration using one battery pack. It will be possible.

Next, in the sixth electric working machine 29, the fourth conversion power supply 95 is the first voltage having the largest output voltage among the plurality of voltage output units (first voltage output unit 102a, second voltage output unit 102b). It is connected not to the output unit 102a but to the second voltage output unit 102b having the smallest output voltage. That is, the fourth conversion power supply 95 may convert the first battery voltage VB1 (VB1 = 72 [V]) output from the first voltage output unit 102a into a constant voltage Vcc (Vcc = 5 [V]). It is configured to convert the second battery voltage VB2 (VB1 = 36 [V]) into a constant voltage Vcc.

As a result, the fourth conversion power supply 95 can reduce the amount of voltage change in the voltage conversion in the fourth conversion power supply 95 as compared with the case where the first battery voltage VB1 is converted to a constant voltage Vcc. Therefore, the sixth electric work machine 29 can reduce the power loss due to the voltage conversion in the fourth conversion power supply 95 as compared with the case where the amount of voltage change is large.

Next, in the sixth electric working machine 29, the "third conversion power supply 93 and the fourth conversion power supply 95" (corresponding to an example of the first conversion power supply) are among the plurality of voltage output units of the plurality of output power supplies 102. The output voltage (VB1 = 72 [V]) is larger than the output voltage (VB2 = 36 [V]) of the second voltage output unit 102b to which the fourth conversion power supply 95 (corresponding to an example of the second conversion power supply) is connected. It is connected to the first voltage output unit 102a. As a result, the amount of power that can be output from the "third conversion power supply 93 and the fourth conversion power supply 95" becomes larger than the amount of power that can be output when the fourth conversion power supply 95 is used alone, and the "third conversion power supply" The 93 and the fourth conversion power supply 95 ”can supply sufficient power to the control unit 62 as compared with the case where the fourth conversion power supply 95 is used alone.

[6-3. Correspondence of wording]
Here, the correspondence between words will be described.
The sixth electric work machine 29 corresponds to an example of the electric work machine, the plurality of output power supplies 102 correspond to an example of the power supply, the sixth control unit power supply 151 corresponds to an example of the power supply for the control unit, and "third conversion". The power supply 93 and the fourth conversion power supply 95 correspond to an example of the first conversion power supply, and the single unit of the fourth conversion power supply 95 corresponds to an example of the second conversion power supply.

[7. Other embodiments]
Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments, and can be implemented in various modes without departing from the gist of the present disclosure.

(A) In the third embodiment and the fourth embodiment, the mode in which the status notification signal Smo output from the control unit 62 is not used has been described, but the status notification is performed as in the first and second embodiments. It may be changed to the form which uses the signal Smo. For example, in the third electric work machine 23 of the third embodiment, in addition to the current notification signal Sia output from the bypass current determination unit 115, the status notification signal Smo (first status notification signal Smo1, second status notification signal Smo2) May be input to the operating state determination unit 75. That is, the operation state determination unit 75 may be configured to be able to receive the first state notification signal Smo1 and the second state notification signal Smo2.

When the bypass current Ibp is larger than the operation reference value Is or the first state notification signal Smo1 is received, the operation state determination unit 75 determines that the operation state of the control unit 62 is the control operation state. To do. When the bypass current Ibp is equal to or less than the operation reference value Is and the second state notification signal Smo2 is received, the operation state determination unit 75 determines that the operation state of the control unit 62 is a low power operation state.

In this electric work machine, the operation state determination unit 75 of the control unit 62 is based on the first state notification signal Smo1 and the second state notification signal Smo2, in addition to the comparison result of the bypass current Ibp and the operation reference value Is. It is possible to determine the operating state.

Similarly, in the fourth electric work machine 25 of the fourth embodiment, in addition to the current notification signal Sia output from the second bypass current determination unit 131, the status notification signal Smo (first status notification signal Smo1, first 2 The status notification signal Smo2) may be input to the operation status determination unit 75.

Further, the operation determination process executed by the operation state determination unit 75 may be replaced with the operation determination process as the internal process of the control unit 62. For example, the control unit 62 controls the first switching unit 67 by generating the energization command signal Sc1 using the trigger signal Str and the status notification signal Smo and outputting the energization command signal Sc1 to the first switching unit 67. You may. Alternatively, the control unit 62 is configured to be able to receive the current notification signal Sia, generates the energization command signal Sc1 using the trigger signal Str and the current notification signal Sia, and sends the energization command signal Sc1 to the first switching unit 67. The first switching unit 67 may be controlled by outputting.

(B) The first backflow current suppression unit 69 is not limited to a configuration including a switching unit such as an FET, and can suppress the inflow of backflow current such as a Schottky diode, and in the forward direction. Any configuration can be adopted as long as the voltage drop when a current is passed is low. The same applies to the second backflow current suppression unit 73.

(C) In the above embodiment, the configuration in which the constant voltage Vcc = 5 [V], the battery voltage VB = 36 [V], and the second constant voltage Vdd = 15 [V] has been described, but each of these voltages is described. The value is not limited to, and may be another appropriate value depending on the application of the electric work machine and the like.

Further, in the above embodiment, the configuration including only the conversion power supply for step-down conversion of the voltage has been described, but the electric work machine of the present disclosure may be configured to include the conversion power supply for step-up conversion of the voltage. For example, in the second embodiment, the third conversion power supply 93 is configured to step down the battery voltage VB to the second constant voltage Vdd, but as another embodiment, the third conversion power supply 93 is the battery voltage VB (36 [V]. ]) Is stepped up to the third constant voltage Vee (for example, 51 [V]), and then the fifth conversion power supply (not shown) steps down the third constant voltage Vee to the second constant voltage Vdd (15 [V]). A configuration to be converted may be adopted. Since the third constant voltage Vee has a higher voltage than the battery voltage VB, it can be used as a power source for, for example, a high-side FET. Further, by providing a conversion power source that boosts and converts the voltage, for example, even if the battery voltage VB drops below the second constant voltage Vdd (15 [V]) due to an abnormality in the battery pack 100, the second constant voltage Vdd is generated. Becomes possible.

(D) The electric work machine to which the present disclosure can be applied is not limited to a rechargeable impact driver, for example, an electric hammer, an electric hammer drill, an electric drill, an electric driver, an electric wrench, an electric reciprocal saw, an electric jigsaw, an electric cutter, and the like. Electric chainsaw, electric canna, electric tacker, electric nail gun, electric hedge trimmer, electric lawn mower, electric lawn mower, electric brush cutter, electric cleaner, electric blower, electric grinder, electric impact driver, electric marunoco, electric hammer It may be a driver, etc.

(E) The functions of one component in the above embodiment may be dispersed as a plurality of components, or the functions of the plurality of components may be integrated into one component. Further, at least a part of the configuration of the above embodiment may be replaced with a known configuration having the same function. Further, a part of the configuration of the above embodiment may be omitted. In addition, at least a part of the configuration of the above embodiment may be added or replaced with the configuration of the other above embodiment. It should be noted that all aspects included in the technical idea specified only by the wording described in the claims are embodiments of the present disclosure.

1 ... Electric work machine, 9 ... Trigger operation unit, 21 ... 2nd electric work machine, 23 ... 3rd electric work machine, 25 ... 4th electric work machine, 27 ... 5th electric work machine, 29 ... 6th electric work Machine, 61 ... motor, 62 ... control unit, 63 ... motor drive unit, 64 ... control unit power supply, 65 ... first conversion power supply, 67 ... first switching unit, 69 ... first backflow current suppression unit, 71 ... 2 conversion power supply, 73 ... 2nd backflow current suppression unit, 75 ... operation state determination unit, 81 ... constant voltage supply line, 91 ... power supply for 2nd control unit, 93 ... 3rd conversion power supply, 95 ... 4th conversion power supply, 97 ... Brushless motor, 99 ... Motor driver, 100 ... Battery pack, 102 ... Multiple output power supply, 111 ... Power supply for 3rd control unit, 113 ... Backflow current suppression unit, 115 ... Bypass current determination unit, 121 ... 4th control unit Power supply, 131 ... 2nd bypass current determination unit, 141 ... power supply for 5th control unit, 151 ... power supply for 6th control unit.

Claims (13)

It is an electric work machine equipped with a drive unit that is driven by using the power supply from the power source.
A control unit configured to control the drive unit and
A control unit power supply that converts the power source power from the power source into a voltage and supplies the control unit power after voltage conversion to the control unit.
With
The control unit is configured to be switchable to a plurality of operation states including at least a control operation state for controlling the drive unit and a low power operation state having lower power consumption than the control operation state.
The power supply for the control unit
When the power source power from the power source is converted into voltage, the first conversion power source configured to be able to supply the maximum current during control, which is the maximum current consumption of the control unit in the control operating state,
When converting the power source power from the power source into a voltage, it is possible to supply the maximum current at low power consumption, which is the maximum current consumption of the control unit in the low power operation state, and the maximum output current is the maximum current during control. With a second conversion power supply configured smaller than
With
The electric work machine
The operation state determination unit for determining whether the operation state of the control unit is the control operation state or the low power operation state is provided.
Further, when the operation state determination unit determines that the operation state of the control unit is the control operation state, the power supply for the control unit is supplied to the control unit by using at least the first conversion power supply. When the state shifts to the first conversion state for supplying the power for the control unit and the operation state of the control unit is determined to be the low power operation state by the operation state determination unit, the voltage generated by the first conversion power supply The conversion is stopped, and at least the second conversion power source is used to shift to the second conversion state in which the power for the control unit is supplied to the control unit.
Electric work machine. The electric work machine according to claim 1.
The power supply for the control unit is configured to shift the operating state to the first conversion state when the electric work machine is operated by the user.
Electric work machine. The electric work machine according to claim 1 or 2.
A first backflow current suppressing unit for suppressing the inflow of backflow current to the output unit of the first conversion power supply is provided.
Electric work machine. The electric work machine according to any one of claims 1 to 3.
The power supply for the control unit
A first current path that is a part of the current path from the power source to the control unit and is provided with the first conversion power source, and
A second current path that is connected in parallel to the first current path and is provided with the second conversion power supply, and a second current path.
With
Each of the first conversion power supply and the second conversion power supply converts the power supply power into the control unit power having a control unit voltage lower than the power supply voltage output by the power supply, and after voltage conversion, the said It is configured to be able to supply power for the control unit.
The first conversion state of the power supply for the control unit is a state in which the power for the control unit is supplied to the control unit by using the first conversion power supply at least via the first current path.
In the second conversion state of the power supply for the control unit, the voltage conversion by the first conversion power supply is stopped, and the control unit is connected to the control unit by using the second conversion power supply at least via the second current path. It is in a state of supplying power.
Electric work machine. The electric working machine according to claim 4.
A second backflow current suppressing unit that suppresses the inflow of backflow current to the output unit of the second conversion power supply is provided between the second conversion power supply and the control unit in the second current path.
Electric work machine. The electric work machine according to claim 4 or 5.
The output voltage of the first conversion power supply and the output voltage of the second conversion power supply are the same voltage value.
Electric work machine. The electric work machine according to any one of claims 4 to 6.
The operation state determination unit includes a first state notification signal indicating that the operation state of the control unit is the control operation state, and a second state indicating that the operation state of the control unit is the low power operation state. When the notification signal and the first state notification signal are received, it is determined that the operation state of the control unit is the control operation state, and the second state notification signal is transmitted. When it is received, it is determined that the operating state of the control unit is the low power operating state.
Electric work machine. The electric work machine according to any one of claims 1 to 3.
The power supply for the control unit
A third current path that is a part of the current path from the power source to the control unit and is provided with the first conversion power source, and a third current path.
A bypass current path connected in parallel to the third current path and
A common current path that is connected in series to each of the third current path and the bypass current path and is provided with the second conversion power supply, and a common current path.
With
The first conversion power supply is configured to be capable of supplying the intermediate power supply power after voltage conversion by converting the power supply power into an intermediate power supply power having an intermediate power supply voltage lower than the power supply voltage output by the power supply.
The second conversion power source converts the power supply power or the intermediate power supply power into the control unit power having a control unit voltage lower than the intermediate power supply voltage, and supplies the control unit power after voltage conversion. Configured to be possible
In the first conversion state of the control unit power supply, the control unit power is supplied to the control unit by using the first conversion power supply and the second conversion power supply via at least the third current path and the common current path. Is in a state of supplying
In the second conversion state of the power supply for the control unit, the voltage conversion by the first conversion power supply is stopped, and the control unit uses the second conversion power supply at least via the bypass current path and the common current path. Is in a state of supplying power for the control unit.
Electric work machine. The electric work machine according to claim 8.
The operating state determination unit is configured to determine whether or not the bypass current flowing in the bypass current path is larger than a predetermined operation reference value.
Further, when the bypass current is larger than the operation reference value, the operation state determination unit determines that the operation state of the control unit is the control operation state, and the bypass current is equal to or less than the operation reference value. In the case of, it is determined that the operating state of the control unit is the low power operating state.
Electric work machine. The electric work machine according to claim 9.
The operation state determination unit includes a first state notification signal indicating that the operation state of the control unit is the control operation state, and a second state indicating that the operation state of the control unit is the low power operation state. Notification signal and is configured to be receivable and
Further, when the bypass current is larger than the operation reference value or the first state notification signal is received, the operation state determination unit determines that the operation state of the control unit is the control operation state. When the bypass current is equal to or less than the operation reference value and the second state notification signal is received, it is determined that the operation state of the control unit is the low power operation state.
Electric work machine. The electric work machine according to any one of claims 1 to 3.
The power supply includes a plurality of battery packs, and includes a plurality of voltage output units that output different voltages.
Each of the first conversion power supply and the second conversion power supply converts the output voltage of any one of the plurality of voltage output units into a voltage.
Electric work machine. The electric work machine according to claim 11.
The second conversion power supply is connected to the voltage output unit having the smallest output voltage among the plurality of voltage output units.
Electric work machine. The electric work machine according to claim 11 or 12.
The first conversion power supply is connected to the voltage output unit having an output voltage larger than the output voltage of the voltage output unit to which the second conversion power supply is connected among the plurality of voltage output units.
Electric work machine.

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