JP2026000038A - Excavator - Google Patents

Abstract

To warm up hydraulic oil and the inside of a cab in a short time while suppressing excessive battery consumption.
[Solution] A shovel having a driver's cab for operating the shovel, a first flow path through which a first liquid circulates to adjust the temperature inside the driver's cab, a second flow path through which a second liquid circulates to drive the shovel, and a heat exchanger that exchanges heat between the first liquid circulating through the first flow path and the second liquid circulating through the second flow path.
[Selected Figure] Figure 3

Description

This disclosure relates to a shovel.

It is known that in excavators, the exhaust heat generated by warming the hydraulic oil in the hydraulic system is provided to the air conditioning system to heat the cab (see, for example, Patent Document 1).

Patent No. 7315296

When heating the cab by providing the exhaust heat generated by warming the hydraulic oil in a hydraulic system to the air conditioning system, the cab cannot be heated unless the hydraulic oil is warmed. However, because the hydraulic oil in a hydraulic system is warmed by circulating it within a flow path, it takes time for the temperature to rise, and therefore it also takes time to heat the cab.

In addition, because the hydraulic oil is warmed up by circulating it through a highly loaded flow path, a large amount of electricity is required just for the warm-up operation, resulting in high battery consumption.

Therefore, it is desirable to warm up the hydraulic oil and the driver's cab in a short period of time while preventing excessive battery consumption.

In order to achieve the above object, the present disclosure:
A shovel,
an operator's cab for operating the shovel;
a first flow path through which a first liquid for adjusting a temperature inside the cab circulates;
a second flow path through which a second liquid for driving the shovel circulates;
The system further includes a heat exchanger that exchanges heat between the first liquid circulating through the first flow path and the second liquid circulating through the second flow path.

This disclosure makes it possible to warm up the hydraulic oil and the driver's cab in a short period of time while preventing excessive battery consumption.

1 is a side view showing a shovel according to an embodiment. FIG. FIG. 1 is a block diagram illustrating an example of a configuration of a shovel according to an embodiment of the present invention. FIG. 2 is a diagram for explaining a configuration example of a heating system mounted on the excavator according to the present embodiment. FIG. 10 is a diagram for explaining the operation of the shovel when it starts to be driven. 10A and 10B are diagrams for explaining the operation after the temperature of the hydraulic oil has increased due to warm-up operation of the excavator. FIG. 10 is a diagram for explaining the operation when the heating system is driven independently.

Embodiments of the present invention will be described below with reference to the drawings. Note that the embodiments described below are illustrative and do not limit the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention. Note that identical or corresponding components in each drawing will be designated by identical or corresponding reference numerals, and descriptions thereof may be omitted.

First, we will provide an overview of the excavator according to one embodiment.

[Outline of the excavator]
FIG. 1 is a side view showing a shovel according to one embodiment.

The excavator 200 according to this embodiment comprises a lower running body 1, an upper rotating body 3 rotatably mounted on the lower running body 1 via a rotating mechanism 2, a boom 4, an arm 5, and a bucket 6 as attachments, and a cabin 10.

The lower traveling body 1 includes, for example, a pair of left and right crawlers, each of which is hydraulically driven by traveling hydraulic motors 1A, 1B (see Figure 2), thereby allowing it to self-propel.

The upper rotating body 3 is hydraulically driven by the swing hydraulic motor 2M (see Figure 2) through the swing mechanism 2, causing it to swing relative to the undercarriage 1. All driven elements (e.g., the swing hydraulic motor 2M) are hydraulically driven by hydraulic oil supplied from the main pump 14 (see Figure 2). This corresponds to a configuration in which the power source (engine) of a hydraulic excavator is replaced with a pump electric motor 12.

In addition, the upper rotating body 3 may be driven to rotate by a rotating electric motor powered by power supplied from the battery module 19 (see FIG. 2) instead of the rotating hydraulic motor 2M. In this case, for example, the excavator 200 is connected to the rotating electric motor from the battery module 19 via a power conversion device 100 (see FIG. 2) and an inverter. The rotating electric motor may then perform power running to rotate the upper rotating body 3, and regenerative running to generate regenerative power to brake the upper rotating body 3 while rotating, under the control of the excavator controller 30 and the inverter. The rotating electric motor may also supply regenerative power to the battery module 19 or the pump electric motor 12 (see FIG. 2) via an inverter.

The boom 4 is attached to the front center of the upper rotating body 3 so that it can be raised and lowered. An arm 5 is attached to the tip of the boom 4 so that it can rotate up and down, and a bucket 6 is attached to the tip of the arm 5 so that it can rotate up and down. The boom 4, arm 5, and bucket 6 are hydraulically driven by hydraulic actuators: a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9, respectively.

The bucket 6 is an example of an end attachment, and other end attachments may be attached to the tip of the arm 5 instead of the bucket 6, depending on the type of work being performed. The other end attachment may be a different type of bucket from the bucket 6, such as a slope bucket or a dredging bucket. The other end attachment may also be a different type of end attachment from the bucket, such as a breaker, mixer, or grapple.

The cabin 10 is an example of a driver's cab for operating the excavator 200. The cabin 10 is mounted on the front left side of the upper rotating body 3, and its interior (interior) is equipped with a driver's seat where the operator sits, an operating device 26 (see Figure 2) described below, and other components.

The excavator 200 operates driven elements such as the lower traveling structure 1 (left and right crawlers), upper rotating structure 3, boom 4, arm 5, and bucket 6 in response to operations by an operator seated in the cabin 10.

Furthermore, instead of or in addition to being configured to be operable by an operator inside the cabin 10, the shovel 200 may be configured to be remotely operable from outside the shovel 200. When the shovel 200 is remotely operated, the interior of the cabin 10 may be unmanned. The following explanation will be given on the assumption that operator operation includes at least one of operation of the operating device 26 by the operator inside the cabin 10 and remote operation by an external operator.

Remote operation includes, for example, a mode in which the shovel 200 is operated by operational inputs related to the actuator of the shovel 200 performed by a specified external device. In this case, the shovel 200 may be equipped with a communication device (not shown) capable of communicating with the specified external device, and may transmit image information (captured images) output by an imaging device (not shown) to the external device. The external device may then display the received image information (captured images) on a display device (hereinafter referred to as a "remote operation display device") provided within the external device. Furthermore, various information images (information screens) displayed on the output device 50 (display device) inside the cabin 10 of the shovel 200 may also be displayed on the remote operation display device of the external device. This allows the operator of the external device to remotely operate the shovel 200 while checking the display contents of, for example, captured images and information screens showing the surroundings of the shovel 200 displayed on the remote operation display device. The excavator 200 may operate hydraulic actuators in response to remote control signals indicating the content of the remote control, which are received from an external device by the communication device, to drive driven elements such as the lower traveling body 1 (left and right crawlers), upper rotating body 3, boom 4, arm 5, and bucket 6.

Remote control may also include, for example, a mode in which the shovel 200 is operated by external voice input or gesture input to the shovel 200 by a person (e.g., a worker) around the shovel 200. Specifically, the shovel 200 recognizes voices uttered by surrounding workers and gestures made by the workers through a voice input device (e.g., a microphone) or a gesture input device (e.g., an imaging device) mounted on the shovel 200 (its own machine). The shovel 200 may then operate actuators in accordance with the content of the recognized voices and gestures, thereby driving driven elements such as the lower traveling body 1 (left and right crawlers), upper rotating body 3, boom 4, arm 5, and bucket 6.

The shovel 200 may also operate the actuators automatically, regardless of the operator's operation. This allows the shovel 200 to realize a function (so-called "automatic driving function" or "machine control function") that automatically operates at least some of the driven elements, such as the lower traveling body 1, upper rotating body 3, boom 4, arm 5, and bucket 6.

The autonomous driving function may include a function (a so-called "semi-autonomous driving function") that automatically operates driven elements (actuators) other than the driven element (hydraulic actuator) that is the target of operation, in response to an operator's operation of the control device 26 or remote operation. The autonomous driving function may also include a function (a so-called "fully autonomous driving function") that automatically operates at least some of the multiple driven elements (actuators) without the operator's operation of the control device 26 or remote operation. When the fully autonomous driving function is enabled in the shovel 200, the interior of the cabin 10 may be unmanned. The semi-autonomous driving function, fully autonomous driving function, etc. may also include a mode in which the operation of the driven element (actuator) that is the target of autonomous driving is automatically determined in accordance with predefined rules. The semi-autonomous driving function, fully autonomous driving function, etc. may also include a mode in which the shovel 200 autonomously makes various decisions and, based on the results of those decisions, autonomously determines the operation of the driven element (actuator) that is the target of autonomous driving (a so-called "autonomous driving function").

[Excavator configuration]
Next, the configuration of a shovel 200 according to this embodiment will be described with reference to FIG. 2 in addition to FIG.

Figure 2 is a block diagram showing an example of the configuration of a shovel 200 according to this embodiment. In Figure 2, mechanical power lines are indicated by double lines, hydraulic lines by thick solid lines, pilot lines by dashed lines, and electric drive and control lines by thin solid lines.

<Hydraulic drive system>
The hydraulic drive system of the excavator 200 according to this embodiment includes hydraulic actuators such as traveling hydraulic motors 1A, 1B, a swing hydraulic motor 2M, a boom cylinder 7, an arm cylinder 8, and a bucket cylinder 9, which hydraulically drive each of the driven elements such as the lower traveling body 1, the boom 4, the arm 5, and the bucket 6. The hydraulic drive system of the excavator 200 according to this embodiment also includes a pump electric motor 12, a main pump 14, and a control valve 17.

The pump electric motor 12 is an example of an electric motor in the present invention and is the power source for the hydraulic drive system. The pump electric motor 12 is, for example, an interior permanent magnet (IPM) motor. The pump electric motor 12 is connected to a high-voltage power supply including a battery module 19 and a power conversion device 100 via an inverter 18A. The pump electric motor 12 runs on three-phase AC power supplied from the battery module 19 via the inverter 18A, and drives the main pump 14 and pilot pump 15. Drive control of the pump electric motor 12 may be performed by the inverter 18A under the control of the excavator controller 30, which will be described later.

The main pump 14 is an example of a hydraulic pump in the present invention and is used to drive the excavator 200. The main pump 14 draws hydraulic oil from a hydraulic oil tank T and discharges it into a high-pressure hydraulic line 16, thereby supplying the hydraulic oil to a control valve 17 through the high-pressure hydraulic line 16. The main pump 14 is driven by a pump motor 12. The main pump 14 is, for example, a variable displacement hydraulic pump, and a regulator (not shown) controls the angle (tilt angle) of the swash plate under the control of the excavator controller 30, which will be described later. This allows the main pump 14 to adjust the stroke length of the piston and thereby adjust the discharge flow rate (discharge pressure).

The main pump 14 may be driven by power from another power source in addition to the pump motor 12. For example, the main pump 14 may be driven by regenerating the energy of hydraulic oil discharged from the boom cylinder 7 or arm cylinder 8 to a hydraulic oil tank due to the weight of the boom 4 or arm 5 when the boom 4 is lowered or the arm 5 is closed. Specifically, a hydraulic motor arranged coaxially with the rotational axis of the main pump 14 may be driven by the energy of hydraulic oil discharged from the boom cylinder 7 or arm cylinder 8 to a hydraulic oil tank due to the weight of the boom 4 or arm 5 when the boom 4 is lowered or the arm 5 is closed. Furthermore, the energy of hydraulic oil discharged from the boom cylinder 7 or arm cylinder 8 to a hydraulic oil tank due to the weight of the boom 4 or arm 5 when the boom 4 is lowered or the arm 5 is closed may be regenerated and used to generate electricity in a generator. Specifically, when the boom 4 is lowered or the arm 5 is closed, the energy of the hydraulic oil discharged from the boom cylinder 7 or arm cylinder 8 into the hydraulic oil tank due to the weight of the boom 4 or arm 5 drives a hydraulic motor arranged coaxially with the generator, causing the generator to generate electricity. In this case, the power generated by the generator may be supplied to the pump motor 12 or charged into the battery module 19.

The control valve 17 is a hydraulic control device that controls the hydraulic drive system in response to operator operation or operational commands corresponding to the automatic driving function. As described above, the control valve 17 is connected to the main pump 14 via the high-pressure hydraulic line 16 and is configured to selectively supply hydraulic oil supplied from the main pump 14 to the hydraulic actuators (travel hydraulic motors 1A, 1B, swing hydraulic motor 2M, boom cylinder 7, arm cylinder 8, and bucket cylinder 9). For example, the control valve 17 is a valve unit including multiple control valves (directional control valves) that control the flow rate and direction of hydraulic oil supplied from the main pump 14 to each hydraulic actuator. The hydraulic oil supplied from the main pump 14 and flowing through the control valve 17 and hydraulic actuators is discharged from the control valve 17 to the hydraulic oil tank T.

<Electric drivetrain>
The electric drive system of the shovel 200 according to this embodiment includes the pump motor 12, the sensor 12s, and the inverter 18A. The electric drive system of the shovel 200 according to this embodiment also includes a high-voltage power supply configured by a battery module 19, a power conversion device 100, etc.

The sensor 12s includes a current sensor 12s1, a voltage sensor 12s2, and a rotation state sensor 12s3.

Current sensor 12s1 detects the current in each of the three phases (U phase, V phase, and W phase) of pump motor 12. Current sensor 12s1 is provided, for example, in the power path between pump motor 12 and inverter 18A. Detection signals corresponding to the current in each of the three phases of pump motor 12 detected by current sensor 12s1 are directly input to inverter 18A via a communication line. Alternatively, these detection signals may be input to shovel controller 30 via the communication line and input to inverter 18A via shovel controller 30.

The voltage sensor 12s2 detects the voltage applied to each of the three phases of the pump motor 12. The voltage sensor 12s2 is provided, for example, in the power path between the pump motor 12 and the inverter 18A. The detection signals corresponding to the voltages applied to each of the three phases of the pump motor 12 detected by the voltage sensor 12s2 are directly input to the inverter 18A via a communication line. Alternatively, the detection signals may be input to the shovel controller 30 via the communication line and input to the inverter 18A via the shovel controller 30.

The rotational state sensor 12s3 detects the rotational state (e.g., rotational position (rotational angle), rotational speed, etc.) of the pump motor 12. The rotational state sensor 12s3 is, for example, a rotary encoder or a resolver.

The inverter 18A drives and controls the pump motor 12 under the control of the shovel controller 30. The inverter 18A includes, for example, a conversion circuit that converts DC power to three-phase AC power and three-phase AC power to DC power, a drive circuit that switches and drives the conversion circuit, and a control circuit that outputs a control signal (for example, a PWM (Pulse Width Modulation) signal) that defines the operation of the drive circuit.

The control circuit of the inverter 18A controls the drive of the pump motor 12 while monitoring the operating state of the pump motor 12. For example, the control circuit of the inverter 18A monitors the operating state of the pump motor 12 based on the detection signal of the rotation state sensor 12s3. The control circuit of the inverter 18A may also monitor the operating state of the pump motor 12 by sequentially estimating the rotation angle of the rotating shaft of the pump motor 12, etc., based on the detection signal of the current sensor 12s1 and the detection signal of the voltage sensor 12s2 (or a voltage command value generated during the control process).

In addition, at least one of the drive circuit and control circuit of inverter 18A may be provided external to inverter 18A.

The battery module 19 supplies charged power to each component within the shovel 200.

The power conversion device 100 boosts the power of the battery module 19, or reduces the power from the pump motor 12 via the inverter 18A and stores it in the battery module 19. The power conversion device 100 switches between boost and buck operation depending on the operating state of the pump motor 12 so that the voltage value of the DC (Direct Current) bus 110 falls within a certain range. The switching control between the boost and buck operation of the power conversion device 100 may be performed by the excavator controller 30, for example, based on the detected voltage value of the DC bus 110, the detected voltage value of the battery module 19, and the detected current value of the battery module 19.

Note that if there is no need to boost the output voltage of the battery module 19 and apply it to the pump motor 12, the power conversion device 100 may be omitted.

<Operation system>
The operating system of the shovel 200 according to this embodiment includes a pilot pump 15 , an operating device 26 , and a pressure control valve 31 .

The pilot pump 15 supplies pilot pressure to various hydraulic equipment (e.g., pressure control valve 31) mounted on the excavator 200 via a pilot line 25. As a result, under the control of the excavator controller 30, the pressure control valve 31 can supply pilot pressure to the control valve 17 according to the operation content (e.g., the amount of operation and the direction of operation) of the operating device 26. Therefore, the excavator controller 30 and the pressure control valve 31 can realize the operation of the driven element (hydraulic actuator) according to the operation content of the operating device 26 by the operator. Furthermore, under the control of the excavator controller 30, the pressure control valve 31 can supply pilot pressure to the control valve 17 according to the remote operation content specified by the remote operation signal. The pilot pump 15 is, for example, a fixed-displacement hydraulic pump, and is driven by the pump motor 12 as described above.

The operating device 26 is located within reach of the operator in the cabin 10's cockpit and is used by the operator to operate each driven element (i.e., the left and right crawlers of the undercarriage 1, the upper rotating body 3, the boom 4, the arm 5, the bucket 6, etc.). In other words, the operating device 26 is used by the operator to operate the hydraulic actuators that drive each driven element (e.g., the traveling hydraulic motors 1A and 1B, the swing hydraulic motor 2M, the boom cylinder 7, the arm cylinder 8, the bucket cylinder 9, etc.). The operating device 26 is, for example, electric and outputs an electrical signal (hereinafter referred to as an "operation signal") corresponding to the operation performed by the operator. The operation signal output from the operating device 26 is input to the excavator controller 30 via a signal line 28. This allows the excavator controller 30 to control the pressure control valve 31 and control the operation of the driven elements (actuators) of the excavator 200 in accordance with the operator's operation and operation commands corresponding to the automatic driving function.

The operating device 26 includes, for example, levers 26A to 26C. Lever 26A may be configured to accept operation of the arm 5 (arm cylinder 8) and the upper rotating body 3 (swing operation) in response to operation in the front-rear and left-right directions, for example. Lever 26B may be configured to accept operation of the boom 4 (boom cylinder 7) and the bucket 6 (bucket cylinder 9) in response to operation in the front-rear and left-right directions, for example. Lever 26C may be configured to accept operation of the lower traveling body 1 (crawler), for example.

Note that if the control valve 17 is configured as an electromagnetic pilot-type control valve (directional control valve), the operation signal from the electric operating device 26 may be input directly to the control valve 17, and each hydraulic control valve may perform an operation according to the operation of the operating device 26. The operating device 26 may also be a hydraulic pilot-type that outputs pilot pressure according to the operation. In this case, the pilot pressure according to the operation is supplied to the control valve 17.

Under the control of the excavator controller 30, the pressure control valve 31 outputs a predetermined pilot pressure using hydraulic oil supplied from the pilot pump 15 through the pilot line 25. The secondary pilot line of the pressure control valve 31 is connected to the control valve 17, and the pilot pressure output from the pressure control valve 31 is supplied to the control valve 17.

<Control system>
The control system of the shovel 200 according to this embodiment includes a shovel controller 30 , an output device 50 , and an input device 52 .

The shovel controller 30 is an example of a control unit in the present invention, and each function may be realized by any hardware or any combination of hardware and software. For example, the shovel controller 30 may be configured primarily with a computer including a processor such as a CPU (Central Processing Unit), a memory device (main storage device) such as RAM (Random Access Memory), a non-volatile auxiliary storage device such as ROM (Read Only Memory), and an interface device for external input/output.

The shovel controller 30 controls the operation of the shovel 200. For example, the shovel controller 30 outputs a control command to the pressure control valve 31 in response to an operation signal input from the operating device 26, causing the pressure control valve 31 to output a pilot pressure corresponding to the operation of the operating device 26. In this way, the shovel controller 30 can realize the operation of the driven elements (hydraulic actuators) of the shovel 200 corresponding to the operation of the electric operating device 26.

Furthermore, when the shovel 200 is remotely operated, the shovel controller 30 may, for example, perform control related to the remote operation. Specifically, the shovel controller 30 may output a control command to the pressure control valve 31, causing the pressure control valve 31 to output a pilot pressure corresponding to the content of the remote operation. In this way, the shovel controller 30 can realize the operation of the shovel 200 (driven element) corresponding to the content of the remote operation.

The shovel controller 30 may also perform control related to, for example, the automatic driving function. Specifically, the shovel controller 30 may output a control command to the pressure control valve 31, and cause the pressure control valve 31 to apply pilot pressure corresponding to the operation command corresponding to the automatic driving function to the control valve 17. In this way, the shovel controller 30 can realize the operation of the driven elements (hydraulic actuators) of the shovel 200 corresponding to the automatic driving function.

The shovel controller 30 may comprehensively control the operation of the entire shovel 200 (various pieces of equipment mounted on the shovel 200).

The shovel controller 30 may control the air conditioning of the shovel 200 by communicating with the air conditioning controller 81. The air conditioning controller 81 will be described later.

The shovel controller 30 controls the drive of the electric drive system based on various input information (e.g., control commands including operation signals from the operating device 26).

The shovel controller 30 may, for example, drive the power conversion device 100 based on the operation state of the operating device 26, and control the step-up and step-down operation of the power conversion device 100, in other words, the switching between the discharged state and the charged state of the battery module 19. Furthermore, for example, when the shovel 200 is remotely operated, the shovel controller 30 may, for example, drive the power conversion device 100 based on the content of the remote operation, and control the switching between the discharged state and the charged state of the battery module 19. Furthermore, for example, when the automatic driving function of the shovel 200 is enabled, the shovel controller 30 may, for example, drive the power conversion device 100 based on an operation command corresponding to the automatic driving function, and control the switching between the discharged state and the charged state of the battery module 19.

The output device 50 is provided within the cabin 10 and outputs various information to the operator under the control of the shovel controller 30. The output device 50 includes, for example, a display device that outputs (notifies) information to the operator in a visual manner. The display device may be installed, for example, in a location within the cabin 10 that is easily visible to the operator, and may display various information images under the control of the shovel controller 30. The display device may be, for example, a liquid crystal display or an organic EL (electroluminescence) display. The output device 50 may also include, for example, an audio output device that outputs information to the operator in an auditory manner. The audio output device may be, for example, a buzzer or speaker.

The input device 52 is provided within the cabin 10 and accepts various inputs from the operator. The input device 52 may include, for example, an operation input device that accepts operation inputs from the operator. The operation input device includes, for example, buttons, toggles, levers, touch panels, touchpads, etc. The input device 52 may also include, for example, a voice input device that accepts voice inputs from the operator and a gesture input device that accepts gesture inputs from the operator. The voice input device includes, for example, a microphone that captures the voice of the operator within the cabin 10. The gesture input device includes, for example, an indoor camera that can capture images of the operator's gestures within the cabin 10. Signals corresponding to inputs from the operator accepted by the input device 52 are taken into the excavator controller 30.

<Heating system>
FIG. 3 is a diagram for explaining an example of the configuration of the heating system 80 mounted on the shovel 200 according to this embodiment.

As shown in FIG. 3, the heating system 80 includes an air conditioning controller 81, a water pump 82, a water heater 83, an HVAC 84, a three-way valve 85, and a heat exchanger 92, and is also provided with a water circulation flow path 86 that forms a flow path through which the cooling water circulates. The heating system 80 is provided to heat the air inside the cabin 10.

The water circulation flow path 86 is an example of a first flow path in the present invention. The water circulation flow path 86 is a flow path that circulates coolant, which is an example of a first liquid in the present invention, between at least the water pump 82, the water heater 83, and the HVAC 84. Furthermore, by switching the three-way valve 85, the water circulation flow path 86 can also include the heat exchanger 92 in the flow path that circulates the coolant.

The water pump 82, under the control of the air conditioning controller 81, draws in and discharges cooling water flowing from the water circulation flow path 86, thereby circulating the cooling water within the water circulation flow path 86.

The water heater 83 is an example of a heater in the present invention. The water heater 83 controls the heating of the cooling water circulating through the water circulation flow path 86 in accordance with control from the air conditioning controller 81. The water heater may be any heater capable of heating the cooling water. For example, a PTC heater may be used.

The water heater 83 also includes a water temperature sensor 83A. The water temperature sensor 83A outputs the detection result of the water temperature in the water circulation flow path 86 to the air conditioning controller 81.

The HVAC (Heating, Ventilation, and Air Conditioning) 84 (an example of an air conditioning device) is configured to adjust the air condition inside the cabin 10. The air condition may be, for example, temperature or humidity. The HVAC 84 in this embodiment is an integrated unit that includes devices for adjusting the air condition, such as a blower, heat exchanger, and humidifier. The HVAC 84 also includes a water temperature sensor 84A. The water temperature sensor 84A detects the water temperature in the water circulation flow path 86 and outputs the results to the air conditioning controller 81.

For example, when coolant is circulating through the water circulation path 86, the HVAC 84, under control of the air conditioning controller 81, extracts heat from the coolant heated by the water heater 83 using a heat exchanger to adjust (e.g., raise) the temperature of the air inside the cabin 10.

The water circulation flow path 86 includes, as part thereof, a first branch flow path 86A that passes through the heat exchanger 92, and a second branch flow path 86B that does not pass through the heat exchanger 92 (bypasses the heat exchanger 92). The three-way valve 85 (an example of a switching valve) is a valve that switches the flow path through which the cooling water circulates in the water circulation flow path 86 between the first branch flow path 86A and the second branch flow path 86B. The flow path switching by the three-way valve 85 is performed based on control from the air conditioning controller 81.

The air conditioning controller 81 controls the entire heating system 80. Specifically, the air conditioning controller 81 controls the HVAC 84, water pump 82, water heater 83, and three-way valve 85 in accordance with control signals from the excavator controller 30 and the detection results of the water temperature sensors 84A and 83A.

For example, when the air conditioning controller 81 receives a control signal from the shovel controller 30 to circulate the cooling water in the water circulation flow path 86, it starts operating the water pump 82. At that time, the air conditioning controller 81 controls the three-way valve 85 in response to the control signal from the shovel controller 30, and switches the flow path through which the cooling water circulates in the water circulation flow path 86 between the first branch flow path 86A and the second branch flow path 86B.

The heating system 80 configured in this manner is configured to allow heat exchange between the hydraulic system 90, which is composed of the hydraulic oil tank T, main pump 14, control valve 17, and high-pressure hydraulic line 16 that circulates hydraulic oil between them. The hydraulic oil circulating through the high-pressure hydraulic line 16 is an example of the second liquid in the present invention and is selectively supplied to the hydraulic actuator via the control valve 17 to drive the excavator 200. When the hydraulic oil is supplied from the main pump 14 to the control valve 17 via the high-pressure hydraulic line 16, which is an example of the second flow path in the present invention, the load on the hydraulic oil increases and its temperature rises. Therefore, heat exchange is performed using a heat exchanger 92 between the hydraulic oil circulating through the high-pressure hydraulic line 16 and discharged from the control valve 17 to the hydraulic oil tank T and the cooling water circulating through the water circulation flow path 86.

The hydraulic system 90 further includes an oil cooler 91 and an oil temperature sensor 93. The oil cooler 91 is located in the high-pressure hydraulic line 16 downstream of the heat exchanger 92 and cools the hydraulic oil circulating through the high-pressure hydraulic line 16 by cooling the hydraulic oil that has passed through the heat exchanger 92. The oil temperature sensor 93 is located between the heat exchanger 92 and the oil cooler 91 and measures the temperature of the hydraulic oil that has undergone heat exchange in the heat exchanger 92. The oil cooler 91 may adjust the degree of cooling of the hydraulic oil using the measurement results of the oil temperature sensor 93. The measurement results of the oil temperature sensor 93 may also be displayed and output to the output device 50.

The following describes the heat exchange between the heating system 80 and hydraulic system 90 described above.

First, we will explain the operation of the excavator 200 when it starts to operate.

Figure 4 is a diagram illustrating the operation of the shovel 200 when it starts to operate.

When the excavator 200 starts to operate and a switch for the heating system 80 (e.g., part of the operating device 26) is operated to heat the cabin 10, the air conditioning controller 81, based on a control signal from the excavator controller 30, causes the water pump 82 to suck in and discharge the cooling water flowing from the water circulation flow path 86, thereby circulating the cooling water within the water circulation flow path 86. The air conditioning controller 81 also heats the cooling water circulating through the water circulation flow path 86 using the water heater 83, based on a control signal from the excavator controller 30.

Meanwhile, in the hydraulic system 90, when the excavator 200 starts operating, the main pump 14 sucks hydraulic oil from the hydraulic oil tank T and discharges it into the high-pressure hydraulic line 16. This causes the hydraulic oil to be supplied to the control valve 17 via the high-pressure hydraulic line 16, and the hydraulic oil circulates through the high-pressure hydraulic line 16. As the hydraulic oil circulating through the high-pressure hydraulic line 16 is supplied from the main pump 14 to the control valve 17 via the high-pressure hydraulic line 16, the load applied to the hydraulic oil increases, causing the temperature to rise. This performs what is known as warm-up operation.

Here, when using the heat of the hydraulic oil to heat the cabin 10, the cabin 10 cannot be heated unless the temperature of the hydraulic oil rises. However, during warm-up operation, the temperature of the hydraulic oil rises as it circulates through the high-pressure hydraulic line 16, so it takes time for the temperature of the hydraulic oil to rise and therefore it also takes time to warm up the cabin 10. Furthermore, in the hydraulic system 90, the hydraulic oil drawn from the hydraulic oil tank T is supplied and circulated by the main pump 14 through the high-pressure hydraulic line 16 to the control valve 17, which is under heavy load. Therefore, in the electric excavator, a large amount of power is required just to warm up. This increases the consumption of the battery in the battery module 19 and shortens the operating time of the electric excavator.

Meanwhile, in the heating system 80, the coolant circulating within the water circulation path 86 is heated by the water heater 83 and supplied to the HVAC 84, which, under control of the air conditioning controller 81, extracts heat from the coolant heated by the water heater 83 using a heat exchanger to raise the temperature of the air inside the cabin 10. In this way, by directly heating the coolant circulating within the water circulation path 86 using the water heater 83, the cabin 10 can be heated in a shorter time than when the heat of the hydraulic oil is used to heat the cabin 10. Here, the water heater 83 that heats the coolant circulating within the water circulation path 86 can be realized with a simpler configuration than one that heats the hydraulic oil circulating through the high-pressure hydraulic line 16. Therefore, by providing a water heater 83 in the water circulation flow path 86 to heat the cooling water circulating through the water circulation flow path 86 and not providing a heater in the high-pressure hydraulic line 16 to heat the hydraulic oil circulating through the high-pressure hydraulic line 16, the heat exchange medium can be heated with a simple configuration.

In addition, the air conditioning controller 81 switches the three-way valve 85 based on a control signal from the shovel controller 30, controlling the cooling water circulating through the water circulation flow path 86 so that it circulates through the first branch flow path 86A of the first branch flow path 86A and the second branch flow path 86B. As a result, the cooling water heated by the water heater 83 flows through the first branch flow path 86A of the first branch flow path 86A and the second branch flow path 86B, and passes through the heat exchanger 92.

As mentioned above, it takes longer for the temperature of the hydraulic oil circulating through the high-pressure hydraulic line 16 to rise than for the temperature of the cooling water circulating through the water circulation flow path 86 to rise. Therefore, when the temperature of the cooling water circulating through the water circulation flow path 86 rises as it is heated by the water heater 83, the temperature of the hydraulic oil circulating through the high-pressure hydraulic line 16 will be lower than the temperature of the cooling water circulating through the water circulation flow path 86 for a while after the excavator 200 starts operating.

Therefore, in the heat exchanger 92, heat exchange occurs between the hydraulic oil circulating through the high-pressure hydraulic line 16 and the cooling water circulating through the water circulation flow path 86. At that time, if the temperature of the hydraulic oil circulating through the high-pressure hydraulic line 16 is lower than the temperature of the cooling water circulating through the water circulation flow path 86, the heat of the cooling water circulating through the water circulation flow path 86 is imparted to the hydraulic oil circulating through the high-pressure hydraulic line 16, as shown in Figure 4.

In this way, the heat of the cooling water circulating through the water circulation flow path 86 is transferred to the hydraulic oil circulating through the high-pressure hydraulic line 16, allowing the temperature of the hydraulic oil to rise in a short period of time and shortening the warm-up time.

Furthermore, in an electric shovel in which the main pump 14 for driving the shovel 200 is provided on the high-pressure hydraulic line 16 and which has a pump motor for driving the main pump 14, battery consumption during warm-up operation can be reduced.

The temperature inside the cabin 10 may be detected, for example, by a temperature sensor included in the HVAC 84. In such a configuration, if the temperature inside the cabin 10 is set, as the air inside the cabin 10 warms and approaches the set temperature, the air conditioning controller 81 may reduce the amount of heating in the water heater 83 to maintain the temperature inside the cabin 10 at the set temperature.

Next, we will explain the operation after the temperature of the hydraulic oil has increased due to warm-up operation of the excavator 200.

Figure 5 is a diagram illustrating the operation after the temperature of the hydraulic oil rises due to warm-up operation of the excavator 200.

As described above, in the hydraulic system 90, the hydraulic oil circulating through the high-pressure hydraulic line 16 is supplied from the main pump 14 to the control valve 17 via the high-pressure hydraulic line 16, which increases the external load and causes the temperature to rise. Therefore, after the hydraulic oil reaches a certain temperature, it is cooled by the oil cooler 91 to prevent the temperature from rising any further. In other words, after warm-up is complete, excess heat is generated in the hydraulic oil.

Therefore, based on a control signal from the excavator controller 30, the air conditioning controller 81 controls the three-way valve 85 so that the cooling water circulating through the water circulation flow path 86 circulates through the first branch flow path 86A of the first branch flow path 86A and the second branch flow path 86B, even after warm-up operation is complete. As a result, the cooling water circulating through the water circulation flow path 86 flows through the first branch flow path 86A of the first branch flow path 86A and the second branch flow path 86B, and passes through the heat exchanger 92.

If the temperature of the hydraulic oil circulating through the high-pressure hydraulic line 16 is higher than the temperature of the cooling water circulating through the water circulation flow path 86, as shown in Figure 5, excess heat generated by the hydraulic oil circulating through the high-pressure hydraulic line 16 will be imparted to the cooling water circulating through the water circulation flow path 86.

Here, water temperature sensors 83A and 84A measure the temperature of the coolant circulating through the water circulation path 86, and the air conditioning controller 81 controls the HVAC 84, water pump 82, water heater 83, and three-way valve 85 in accordance with control signals from the excavator controller 30 and the detection results of the water temperature sensors 84A and 83A. Therefore, when excess heat generated by the hydraulic oil circulating through the high-pressure hydraulic line 16 is imparted to the coolant circulating through the water circulation path 86, and the temperature of the coolant circulating through the water circulation path 86 rises, heating of the coolant by the water heater 83 becomes unnecessary or the amount of heating is reduced, thereby reducing battery consumption in the battery module 19.

Next, we will explain how the heating system operates independently.

Figure 6 is a diagram illustrating the operation of the heating system 80 when it is driven independently.

When the switch of the heating system 80 (e.g., part of the operating device 26) is operated to heat the cabin 10 at the start of operation of the shovel 200, the air conditioning controller 81, based on a control signal from the shovel controller 30, causes the water pump 82 to suck in and discharge coolant flowing from the water circulation flow path 86, thereby circulating the coolant within the water circulation flow path 86. Furthermore, based on a control signal from the shovel controller 30, the air conditioning controller 81 causes the water heater 83 to heat the coolant circulating through the water circulation flow path 86. At this time, when the switch of the heating system 80 is operated to maximize heating capacity, the air conditioning controller 81, based on a control signal from the shovel controller 30, switches the three-way valve 85 to control the coolant circulating through the water circulation flow path 86 so that it circulates through the second branch flow path 86B of the first branch flow path 86A and the second branch flow path 86B. As a result, the coolant heated by the water heater 83 flows through the second branch flow path 86B of the first branch flow path 86A and the second branch flow path 86B, and does not pass through the heat exchanger 92. Note that an operation to maximize the heating capacity of the heating system 80 can be selected using a switch of the heating system 80, and may be selected when it is desired to heat the air in the cabin 10 in a short period of time. Furthermore, when the temperature in the cabin 10 is lower than the set temperature of the cabin 10 by a predetermined temperature or more, if the switch of the heating system 80 is operated, the coolant circulating through the water circulation flow path 86 may be controlled to circulate through the second branch flow path 86B of the first branch flow path 86A and the second branch flow path 86B. For example, when the temperature in the cabin 10 is lower than the set temperature of the cabin 10 by 10° C. or more, the coolant circulating through the water circulation flow path 86 may be controlled to circulate through the second branch flow path 86B of the first branch flow path 86A and the second branch flow path 86B. In such a configuration, if the temperature inside the cabin 10 is not lower than 10°C or more than the set temperature inside the cabin 10, when the switch of the heating system 80 is operated, the cooling water circulating through the water circulation flow path 86 is controlled to circulate through the first branch flow path 86A out of the first branch flow path 86A and the second branch flow path 86B, and heat exchange as shown in Figure 4 occurs.

When the cooling water circulating through the water circulation flow path 86 circulates through the second branch flow path 86B of the first branch flow path 86A and the second branch flow path 86B, the cooling water circulating through the water circulation flow path 86 does not pass through the heat exchanger 92, and therefore heat exchange does not occur between the cooling water circulating through the water circulation flow path 86 and the hydraulic oil circulating through the high-pressure hydraulic line 16. As a result, the heat of the cooling water heated by the water heater 83 is not imparted to the hydraulic oil circulating through the high-pressure hydraulic line 16, and the heat of the cooling water heated by the water heater 83 can be used solely to heat the cabin 10. This allows the air inside the cabin 10 to be heated in a short period of time.

In this way, the excavator controller 30 switches the flow path through which the cooling water circulates between the first branch flow path 86A and the second branch flow path 86B by switching the three-way valve 85 in accordance with the temperature requirements inside the cabin 10. This allows the air inside the cabin 10 to be warmed in a short period of time, for example, when the air temperature inside the cabin 10 is low.

As described above, this embodiment includes a cabin 10 for operating the shovel 200, a water circulation path 86 through which cooling water circulates to adjust the temperature inside the cabin 10, a high-pressure hydraulic line 16 through which hydraulic oil circulates to drive the shovel 200, and a heat exchanger 92 that exchanges heat between the cooling water circulating through the water circulation path 86 and the hydraulic oil circulating through the high-pressure hydraulic line 16. This makes it possible to warm up the hydraulic oil and the cab in a short period of time while preventing excessive battery consumption.

The water circulation flow path 86 also has a first branch flow path 86A that passes through the heat exchanger 92 and a second branch flow path 86B that does not pass through the heat exchanger 92. The excavator controller 30 switches the flow path through which the cooling water circulates between the first branch flow path 86A and the second branch flow path 86B by switching the three-way valve 85. This allows heat exchange to occur between the cooling water circulating through the water circulation flow path 86 and the hydraulic oil circulating through the high-pressure hydraulic line 16 by switching whether the cooling water passes through the heat exchanger 92 or not.

In this embodiment, a first branch flow path 86A that passes through the heat exchanger 92 and a second branch flow path 86B that does not pass through the heat exchanger 92 are provided in part of the water circulation flow path 86. However, the high-pressure hydraulic line 16 through which the hydraulic oil circulates may also be provided with a first branch flow path that passes through the heat exchanger 92 and a second branch flow path that does not pass through the heat exchanger 92. In this case, the excavator controller 30 switches the flow path through which the hydraulic oil circulates between the first branch flow path and the second branch flow path by switching the three-way valve in accordance with the temperature requirements inside the cabin 10.

In addition, in this embodiment, the three-way valve 85 is switched to control the cooling water circulating through the water circulation flow path 86 so that it circulates through either the first branch flow path 86A or the second branch flow path 86B. However, an on-off valve may be provided in each of the first branch flow path 86A and the second branch flow path 86B, and the air conditioning controller 81 may control the cooling water circulating through the water circulation flow path 86 so that it circulates through either the first branch flow path 86A or the second branch flow path 86B by exclusively opening and closing these two on-off valves based on control signals from the excavator controller 30.

REFERENCE SIGNS LIST 1 Lower traveling body 1A, 1B Travel hydraulic motor 2 Swing mechanism 2M Swing hydraulic motor 3 Upper rotating body 4 Boom 5 Arm 6 Bucket 7 Boom cylinder 8 Arm cylinder 9 Bucket cylinder 10 Cabin 12 Pump motor 12s Sensor 14 Main pump 15 Pilot pump 16 High-pressure hydraulic line 17 Control valve 19 Battery module 25 Pilot line 26 Operating device 28 Signal line 30 Excavator controller 31 Pressure control valve 50 Output device 52 Input device 80 Heating system 81 Air conditioning controller 82 Water pump 83 Water heater 83A Water temperature sensor 84 HVAC
84A Water temperature sensor 85 Three-way valve 86 Water circulation flow path 86A First branch flow path 86B Second branch flow path 90 Hydraulic system 91 Oil cooler 92 Heat exchanger 93 Oil temperature sensor 100 Power conversion device 110 DC bus 200 Excavator T Hydraulic oil tank

Claims (5)

A shovel,
an operator's cab for operating the shovel;
a first flow path through which a first liquid for adjusting a temperature inside the cab circulates;
a second flow path through which a second liquid for driving the shovel circulates;
a heat exchanger that performs heat exchange between the first liquid circulating through the first flow path and the second liquid circulating through the second flow path. One of the first flow path and the second flow path is
a first branch flow path passing through the heat exchanger;
a second branch flow path that does not pass through the heat exchanger,
The shovel is
The shovel according to claim 1 , further comprising a control unit that switches a flow path through which the first liquid or the second liquid circulates between the first branch flow path and the second branch flow path. a heater provided in the first flow path for heating the first liquid circulating through the first flow path;
The shovel according to claim 1 , wherein the second flow path does not have a heater that heats the second liquid circulating through the second flow path. The shovel described in claim 2, wherein the control unit switches the flow path through which the first liquid or the second liquid circulates between the first branch flow path and the second branch flow path in response to temperature requirements in the cab. a hydraulic pump provided in the second flow path for driving the shovel;
The shovel according to claim 1, further comprising: an electric motor that drives the hydraulic pump.