JP2019002558A - Rotary driving device, and work machine with the same - Google Patents

Abstract

To provide a rotary driving device which improves operability in a rotary brake operation by applying a desired brake force corresponding to an operation amount of an operation lever to a rotary motor even in a case where a rotation speed of a rotor is changed, and a work machine with the same.SOLUTION: A rotary driving device 100 comprises a rotary motor 20 which rotates a rotor 10, a hydraulic pump 52, an operation lever 56, a control valve 54, a brake valve 71, and a brake valve control part 83. In a case where the operation lever 56 receives a brake operation of the rotary motor 20, the brake valve control part 83 regulates a flow rate of a working oil in the brake valve 71 in such a manner that a differential pressure of the rotary motor 20 becomes a predetermined target pressure Pt corresponding to an operation amount that the operation lever 56 receives, and generates a pressure loss in the working oil in the brake valve 71.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a swivel drive device and a work machine including the same.

  A work machine such as a crane generally includes a lower traveling body, an upper swing body disposed above the lower traveling body, and a swing drive device that drives the upper swing body to swing relative to the lower swing body.

  The turning drive device includes a hydraulic turning motor, a hydraulic pump, a control valve, and an operation lever. The swing motor is disposed between the lower traveling body and the upper swing body, and operates so that the upper swing body rotates upon receiving the supply of hydraulic oil. The turning motor includes a first port and a second port for intake and exhaust of hydraulic oil. The hydraulic pump supplies hydraulic oil to the swing motor. The control valve is interposed between the swing motor and the hydraulic pump, and adjusts the supply flow rate of the hydraulic oil to the swing motor and switches the hydraulic oil supply path. The control valve is constituted by, for example, a pilot operated direction switching valve. The control valve can be switched between a neutral position, a forward rotation drive position, and a reverse rotation drive position in accordance with an operation given to the operation lever. When the control valve is set to the forward rotation drive position, the hydraulic oil discharged from the hydraulic pump flows into the swing motor from the first port and is discharged from the second port. As a result, the turning motor is rotated in the forward direction, and the upper turning body is driven to turn in the right direction. On the other hand, when the control valve is set to the reverse rotation drive position, the hydraulic oil discharged from the hydraulic pump flows into the swing motor from the second port and is discharged from the first port. As a result, the turning motor is rotated in the reverse direction, and the upper turning body is driven to turn leftward.

  Work machines often employ a so-called neutral-free hydraulic circuit in which no load torque is applied to the swing motor at the neutral position of the control valve. Specifically, when the control valve is set to the neutral position, the hydraulic oil discharged from the swing motor is returned to the swing motor through the control valve, so that the upper swing body continues to rotate due to inertia. At this time, a part of the hydraulic oil is discharged to the tank via the bleed-off circuit. In such a neutral-free hydraulic circuit, a braking force is applied to the swing motor as follows. In a state where the control valve is set to the normal rotation drive position and the swing motor rotates to the right, the control valve is switched to the reverse rotation drive position via the neutral position according to the brake operation of the operation lever. As a result, the hydraulic oil discharged from the turning motor and the hydraulic oil supplied from the hydraulic pump merge. The pressure generated at this time acts on the turning motor as a braking force, and the turning speed of the turning motor decreases. In such a brake control technique, it is desired to adjust the braking force applied to the turning motor in accordance with the operation amount given to the operation lever in order to improve the operability of the operator.

  Patent Document 1 discloses a technique in which a bleed-off control valve is provided in a bleed-off circuit of a control valve. In this technique, the opening area of the bleed-off control valve is adjusted according to the operation amount given to the operation lever. When the operation amount given to the operation lever is large, the opening area of the bleed-off control valve is set small. As a result, the pressure at the time of being discharged into the tank through the bleed-off circuit increases, and a large braking force is applied to the turning motor.

JP 2008-143635 A

  The above-described technology has a problem that the operation amount that the operator gives to the operation lever and the braking force applied to the turning motor are difficult to correlate, and the operability of the operation lever in the turning brake operation cannot be sufficiently secured. Specifically, in the above technique, the magnitude of the braking force applied to the turning motor is determined according to the pressure loss of the hydraulic oil in the bleed-off control valve. The pressure loss of the hydraulic oil varies depending on the opening area of the control valve and the flow rate of the hydraulic oil passing through the opening. In this case, since the motor discharge flow rate changes in accordance with the rotation speed of the swing motor (the swing speed of the upper swing body), even if the operation amount given to the operation lever is the same, the turn depends on the rotation speed of the swing motor. The braking force applied to the motor will change. As a result, the amount of operation applied by the operator to the operation lever and the braking force applied to the turning motor are difficult to correlate, and the operability of the operation lever in the turning brake operation cannot be secured sufficiently.

  The present invention has been made in view of the above problems, and even when the turning speed of the revolving body changes, a desired braking force according to the operation amount that the operated part receives is applied to the turning motor. Therefore, an object of the present invention is to provide a turning drive device with improved operability in the turning brake operation, and a work machine equipped with the turning drive device.

  A turning drive device according to one aspect of the present invention is provided in a work machine including a machine body and a turning body disposed above the machine body, and drives the turning body to turn relatively with respect to the machine body. A swivel drive device, which is a hydraulic swivel motor interposed between the airframe and the swivel body to drive the swivel swivel, the swivel motor having a first port and a second port The hydraulic oil is supplied through the first port, thereby turning the swivel body in the first direction and discharging the hydraulic oil through the second port, while receiving the hydraulic oil supply through the second port. As a result, the swivel body is swung in a second direction opposite to the first direction and the working oil is discharged through the first port, and the working oil to be supplied to the swiveling motor is discharged. A hydraulic pump, a first oil passage communicating the hydraulic pump and the first port of the swing motor, a second oil passage communicating the hydraulic pump and the second port of the swing motor, A discharge oil passage that can communicate with the first oil passage and the second oil passage and guides return oil discharged from the turning motor to the tank, and an operated portion that is operated for the turning operation of the turning body. A first operation area for turning the revolving body in the first direction, a second operation area for turning the revolving body in the second direction, the first operation area, and the second operation area; An operation portion that can be selectively operated to a neutral operation region between the first operation region and the second operation region, and the operation amount of the operation portion is variable. And interposed between the hydraulic pump and the swing motor A control valve that supplies hydraulic oil discharged from the hydraulic pump to the first port through the first oil passage and guides hydraulic oil discharged from the second port to the tank through the discharge oil passage. A first turning position that forms an oil passage, and the hydraulic oil discharged from the hydraulic pump is supplied to the second port through the second oil passage and the hydraulic oil discharged from the first port is used for the discharge. Operation between the first port and the second port by communicating the second turning position for forming an oil passage leading to the tank through the oil passage, and the first oil passage and the second oil passage. A control valve capable of switching to a neutral turning position that allows oil to circulate, and a brake valve disposed in the discharge oil passage, wherein the hydraulic oil in the discharge oil passage A brake valve that operates to change the flow rate of hydraulic fluid that passes through the opening, and the swiveled body is swung in the first direction. When the unit receives a first brake operation from the first operation region to the second operation region via the neutral operation region, the differential pressure of the swing motor becomes an operation amount received by the operated unit. The flow rate of the hydraulic oil that passes through the second opening is adjusted so as to achieve a predetermined target pressure, and pressure loss is generated in the hydraulic oil in the brake valve, while the swiveling body turns in the second direction. When the operated portion receives a second brake operation from the second operation region to the first operation region via the operation intermediate region in the state of being operated, the differential pressure of the swing motor is Depending on the amount of operation that the operated part receives To a predetermined target pressure was, and a generating pressure loss, the brake control unit to the hydraulic oil in the brake valve to adjust the flow rate of the hydraulic oil passing through the opening.

  According to this configuration, when the operated portion receives a first brake operation from the first operation region to the second operation region via the neutral operation region while the revolving body is turning in the first direction, Alternatively, when the operated part receives a second brake operation from the second operation region to the first operation region through the neutral operation region while the swinging body is turning in the second direction, A brake pressure is applied to the turning motor by the position change. At this time, the brake control unit adjusts the flow rate of the hydraulic oil in the brake valve so that the differential pressure of the swing motor becomes a predetermined target pressure corresponding to the operation amount received by the operated part, Cause pressure loss. As a result, even if the discharge flow rate of the swing motor changes according to the rotation speed of the swing motor or the discharge flow rate of the hydraulic pump changes during the work of the work machine, the operation amount of the operated part is reduced. A desired braking force can be applied to the turning motor.

  In the above configuration, the brake valve is a flow rate control valve capable of adjusting an opening area of the opening, and the brake control unit is configured such that the operated portion performs the first brake operation or the second brake operation. In this case, it is desirable to adjust the opening area of the opening of the flow control valve so that the differential pressure of the swing motor becomes the target pressure.

  In this case, the brake control unit can apply a desired braking force according to the operation amount of the operated portion to the swing motor by adjusting the opening area of the opening of the flow control valve.

  The brake valve or the brake valve performs a valve opening operation so as to maintain a pressure between the opening and the hydraulic pump in the discharge oil passage below a predetermined relief pressure. The valve, wherein the brake control unit is configured so that the differential pressure of the swing motor becomes the target pressure when the operated portion is subjected to the first brake operation or the second brake operation. The relief pressure of the relief valve may be adjusted.

  According to this configuration, the brake control unit adjusts the relief pressure of the variable relief valve, so that a desired braking force corresponding to the operation amount of the operated unit can be applied to the swing motor.

  In the above configuration, the hydraulic pump is a variable displacement hydraulic pump, and compared with a displacement of the hydraulic pump when the swing body is operated to swing in the first direction or the second direction. It is preferable that the apparatus further includes a pump control unit that reduces a capacity of the hydraulic pump when the operated unit receives the first brake operation or the second brake operation. Furthermore, it is preferable that the brake control unit sets the target pressure so as to compensate for a decrease in braking force applied to the swing motor due to the capacity of the hydraulic pump being set small.

  According to this configuration, during a brake operation that does not require a positive supply of hydraulic oil to the swing motor, the pump capacity of the hydraulic pump is set to be small, and the energy consumed by the hydraulic pump is reduced. Energy saving is realized. At this time, the brake force according to the operation amount of the operated portion can be applied while the decrease in the brake force with respect to the turning motor is suppressed by the operation of the brake valve.

  In the above configuration, the brake control unit receives the first brake release operation from the second operation region to the neutral operation region after the first brake operation, or the operated unit When the second brake release operation from the first operation region to the neutral operation region is received after the second brake operation, the hydraulic pump reduced when receiving the first brake operation or the second brake operation. The pump capacity return operation for increasing the capacity is started, and the pressure loss of the hydraulic oil generated in the brake valve by adjusting the flow rate of the hydraulic oil passing through the opening is started. It is desirable to execute a brake releasing operation that disappears after a predetermined time has elapsed.

  According to this configuration, even if the pump capacity increase takes a predetermined time in the pump capacity return operation, it is possible to prevent the pressure loss generated in the brake valve from disappearing before the pump capacity increases. In other words, the brake valve is prevented from being fully opened. As a result, it is possible to prevent a phenomenon in which the brake pressure decreases transiently.

  A work machine according to another aspect of the present invention includes a machine body, a swing body disposed above the machine body, and the swing drive device according to any one of the above.

  According to this configuration, even when the discharge flow rate of the swing motor changes according to the rotation speed of the swing motor or the discharge flow rate of the hydraulic pump changes during the work of the work machine, A desired braking force can be applied to the swing motor according to the operation amount.

  According to the present invention, even when the turning speed of the turning body changes, it is possible to apply a desired braking force to the turning motor in accordance with the operation amount that the operated part receives, and in the turning brake operation Provided are a turning drive device with improved operability and a work machine equipped with the same.

1 is a side view of a work machine according to an embodiment of the present invention. 1 is a hydraulic circuit diagram of a turning drive device for a work machine according to a first embodiment of the present invention. It is an electrical block diagram of the control part of the turning drive which concerns on 1st Embodiment of this invention. It is a figure which shows a part of hydraulic circuit diagram of the turning drive apparatus of FIG. 2 when the turning body of the working machine according to the first embodiment of the present invention receives a braking operation. It is a flowchart in case the turning body of the working machine which concerns on 1st Embodiment of this invention receives brake operation | movement. In the turning drive device concerning a 1st embodiment of the present invention, it is a graph which shows the relation between the amount of lever operation, motor rotation speed, and target pressure. 5 is a graph showing a relationship between a lever operation amount and a target pressure in the turning drive device according to the first embodiment of the present invention. 5 is a graph showing a relationship between a lever operation amount and a target pressure in the turning drive device according to the first embodiment of the present invention. It is a figure which shows the hydraulic circuit figure of the turning drive apparatus of the working machine which concerns on 2nd Embodiment of this invention. It is a figure which shows the hydraulic circuit figure of the turning drive apparatus of the working machine which concerns on 3rd Embodiment of this invention. It is a flowchart in case the turning body of the working machine which concerns on 4th Embodiment of this invention receives brake operation | movement. It is a flowchart in case the turning body of the working machine which concerns on 5th Embodiment of this invention receives brake operation | movement. It is a part of flowchart when the turning body of the working machine which concerns on 5th Embodiment of this invention receives brake operation | movement. It is a hydraulic-circuit figure of the turning drive apparatus of the working machine which concerns on 8th Embodiment of this invention. It is a figure which shows a part of hydraulic circuit diagram of the turning drive apparatus of FIG. 14 in case the turning body of the working machine which concerns on 8th Embodiment of this invention receives brake operation. It is a figure which shows a part of hydraulic circuit diagram of the turning drive apparatus of FIG. 14 in case the turning body of the working machine which concerns on 8th Embodiment of this invention receives brake operation.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side view of a crane 1 (work machine) according to a first embodiment of the present invention. Note that FIG. 1 shows directions of “up”, “down”, “front”, and “rear”, but these directions are for convenience in order to describe the structure of the crane 1 according to the present embodiment. It is shown and does not limit the use mode of the work machine according to the present invention.

  The crane 1 includes a traveling body 11 (airframe) that can travel on the ground, a revolving body 10 that is disposed above the traveling body 11, and a boom 13 that serves as a hoisting member. Further, a cab 12 is provided at the front end portion of the revolving structure 10. The cab 12 corresponds to the driver seat of the crane 1. The cab 12 is provided with an operation lever 56 and a brake adjusting device 90 (FIGS. 2 and 3) which will be described later.

  The boom 13 shown in FIG. 1 is a so-called lattice type, and includes a lower boom 13A, one or a plurality (one in the illustrated example) intermediate boom 13B, and an upper boom 13C. The boom 13 is pivotally supported (supported) on the revolving structure 10 with a boom foot 13S provided at the lower end as a fulcrum. Further, a sheave 132 is provided at the tip of the boom 13.

  The crane 1 further includes an upper spreader 131, a lower spreader 133, a compression member 14 and a tension member 15 constituting a gantry, a boom hoisting winch 16, and a boom hoisting rope 17. Each of the upper spreader 131 and the lower spreader 133 includes a plurality of sheaves. The upper spreader 131 is connected to the tip of the boom 13 by a boom guy line (guy link). The compression member 14 is a support column erected upward and rearward from a substantially central portion of the revolving structure 10. Similarly, the tension member 15 is a column that is erected vertically upward from the rear end portion of the revolving structure 10, and is connected to the upper end portion of the compression member 14. A gantry sheave 141 is provided at the tip of the gantry. The boom hoisting rope 17 is pulled out from the boom hoisting winch 16 and hung on the gantry sheave 141 of the gantry, and then is hung around the lower spreader 133 and the upper spreader 131 a plurality of times. The boom hoisting winch 16 is disposed on the revolving structure 10. In FIG. 1, the boom hoisting winch 16 is disposed between the compression member 14 and the tension member 15 for the sake of explanation, but in reality, the boom hoisting winch 16 is closer to the turning center than the cab 12. Are arranged on a center section (swivel frame) (not shown). The boom hoisting winch 16 raises and lowers the boom 13 while rotating the boom 13 relative to the gantry by winding and unwinding the boom hoisting rope 17.

  The crane 10 further includes a main winding winch 18 for lifting and lowering a suspended load (lifted body). In the crane 1 according to this embodiment, the main winding winch 18 is provided in the revolving structure 10. A main hook 19F for a suspended load is provided at the tip 19A of the main winding rope 19 drawn out from the main winding winch 18. The main winding rope 19 is stretched between a sheave 132 at the tip of the boom 13 and a sheave of a sheave block (not shown) provided on the main hook. Accordingly, when the main winding winch 18 winds or unwinds the main winding rope 19, the distance between the sheave 132 and the sheave of the main hook 19F changes, and the rope tip portion that is suspended from the tip portion of the boom 13 is changed. The main hook 19F connected to 19A is wound up and down.

<First Embodiment>
The crane 1 further includes a turning drive device 100. FIG. 2 is a hydraulic circuit diagram of the turning drive device 100 of the crane 1 according to the present embodiment. The turning drive device 100 drives the turning body 10 to turn relative to the traveling body 11.

  The turning drive device 100 includes a turning motor 20, a rotation speed sensor 20S (rotation detection unit), a hydraulic pump 52, a first supply line 55A (first oil passage), and a second supply line 55B (second oil passage). ), A bleed offline 55C (discharge oil passage), a control valve 54, an operation lever 56 (operated portion), a relief valve 59, a brake valve 71, a controller 80, and a brake adjusting device 90. Prepare. Note that the pressure sensor 52P shown in FIGS. 2 to 4 is described in the following embodiment (sixth embodiment), and is not necessarily an essential configuration in the present embodiment (FIGS. 9 and 9). 10 is the same).

  The turning motor 20 is disposed so as to be interposed between the traveling body 11 and the turning body 10 of FIG. Specifically, the turning motor 20 includes a motor shaft including a pinion and is fixed to the turning body 10. On the other hand, the traveling body 11 includes a turning gear (not shown) formed in a circumferential shape. As the pinion of the turning motor 20 and the turning gear mesh with each other, the turning body 10 turns according to the rotation of the turning motor 20. For this reason, the turning motor 20 is disposed so as to be located near the circumference of the turning gear. The turning motor 20 is a hydraulic turning motor that drives the turning body 10 to turn. The turning motor 20 has a motor first port 20A (first port) and a motor second port 20B (second port). The turning motor 20 turns the turning body 10 in the first direction (for example, the left direction) by receiving the supply of the working oil through the motor first port 20A, and discharges the working oil through the motor second port 20B. On the other hand, the turning motor 20 turns the turning body 10 in a second direction (for example, the right direction) opposite to the first direction by receiving the supply of hydraulic oil through the motor second port 20B, and through the motor first port 20A. Drain the hydraulic oil.

  The rotational speed sensor 20 </ b> S detects the rotational speed (or rotational speed) of the turning motor 20. The rotation speed sensor 20S detects the rotation direction (first direction, second direction) of the turning motor 20.

  The hydraulic pump 52 receives a driving force of an engine (drive source) (not shown), and sucks and discharges hydraulic oil to be supplied to the turning motor 20 from the tank. The hydraulic pump 52 according to this embodiment is a variable displacement hydraulic pump, and the capacity qp (displacement volume) of the hydraulic pump 52 is changed by the input of a pump command signal to a regulator (not shown) included in the hydraulic pump 52. As a result, the pump discharge flow rate Qp, which is the flow rate of the hydraulic oil discharged from the hydraulic pump 52, changes. In addition, said pump command signal is output from the hydraulic pump control part 82 (FIG. 3) mentioned later.

  The first supply line 55A and the second supply line 55B are oil passages that connect the hydraulic pump 52 and the motor first port 20A and the motor second port 20B of the turning motor 20, respectively, as shown in FIG. The bleed offline 55C can communicate with the first supply line 55A and the second supply line 55B according to the valve position of the control valve 54, and is an oil passage that guides hydraulic oil (return oil discharged from the turning motor 20) to the tank. It is. In the present embodiment, the bleed offline 55C includes a brake line 55D. The brake line 55D constitutes a part of the bleed offline 55C according to the switching position of the control valve 54. The brake line 55D can communicate with the openings A3, B3, and C3 of the control valve 54.

  The control valve 54 is disposed in the hydraulic oil passage so as to be interposed between the hydraulic pump 52 and the turning motor 20. The control valve 54 switches the direction of supply of hydraulic oil from the hydraulic pump 52 to the turning motor 20 and operates to adjust the flow rate of hydraulic oil. The control valve 54 is connected to the motor first port 20A of the turning motor 20 via the first supply line 55A, and is connected to the motor second port 20B of the turning motor 20 via the second supply line 55B.

  In this embodiment, the control valve 54 is configured by an electromagnetic switching type directional switching valve (solenoid valve), and in accordance with a switching signal input to the control valve 54, the left turning position 54A (first turning position), neutral It operates to switch between position 54B (neutral turning position) and right turning position 54C (second turning position). The control valve 54 has a pair of pilot ports, that is, a left turning pilot port 53A and a right turning pilot port 53B. The control valve 54 is maintained at the neutral position 54B when no pilot pressure is input to either the left turning pilot port 53A or the right turning pilot port B. The control valve 54 is switched to the left turn position 54A when the pilot pressure is input to the left turn pilot port 53A, and is switched to the right turn position 54C when the pilot pressure is input to the right turn pilot port 53B. The control valve 54 is opened with an opening area corresponding to the pilot pressure, and changes the flow rate of the hydraulic oil.

  At the left turning position 54A of the control valve 54, openings A1, A2, and A3 are formed. In the left turning position 54A, the control valve 54 receives the hydraulic oil discharged from the hydraulic pump 52 through the opening A1, supplies the hydraulic oil to the motor first port 20A through the first supply line 55A, and also supplies the motor second port. The hydraulic oil discharged from 20B is received through the opening A2, and an oil passage is formed that guides the hydraulic oil to the tank through the bleed offline 55C. The opening A3 functions mainly in the brake operation described later. Openings C1, C2, and C3 are formed at the right turning position 54C of the control valve 54. At the right turning position 54C, the control valve 54 receives the hydraulic oil discharged from the hydraulic pump 52 through the opening C2, supplies the hydraulic oil to the motor second port 20B through the second supply line 55B, and also sets the motor first. The hydraulic oil discharged from the port 20A is received through the opening C1, and an oil passage is formed for guiding the hydraulic oil to the tank through the bleed offline 55C. The opening c3 functions mainly in the brake operation described later. Further, openings B1, B2, and B3 are formed in the neutral position 54B of the control valve 54. In the neutral position 54B, the control valve 54 forms an oil passage that connects the first supply line 55A and the second supply line 55B through the openings B1 and B2 at a position closer to the hydraulic pump 52 than the control valve 54. This allows the hydraulic oil to circulate between the motor first port 20A and the motor second port 20B.

  The operation lever 56 is disposed in the cab 12 (FIG. 1) and is operated by an operator for the turning operation of the turning body 10. The operation lever 56 includes a first operation area S1 for turning the revolving body 10 in the first direction, a second operation area S2 for turning the revolving body 10 in the second direction, a first operation area, and a second operation area. Can be selectively operated to a neutral operation region SS between Further, the operation amount of the operation lever 56 in the first operation area S1 and the second operation area S2 is variable.

  When the operation lever 56 is operated in the first operation region S1 by the operator (first turning operation), the left turn pilot of the control valve 54 is controlled through the left turn command line 57A of FIG. 2 according to the operation amount received by the operation lever 56. The pilot pressure to the port 53A is changed (depressurized). Further, when the operation lever 56 is operated in the second operation area S2 by the operator (second turning operation), the control valve 54 is passed through the right turn command line 57B of FIG. 2 according to the operation amount received by the operation lever 56. The pilot pressure to the right turn pilot port 53B is changed (depressurized). The operation information (operation area, operation amount) received by the operation lever 56 is also transmitted to the controller 80.

  The relief valve 59 operates so that the pressure of the bleed offline 55C does not exceed a predetermined pressure. Specifically, the relief valve 59 operates to keep the primary pressure at a pressure equal to or lower than the relief pressure by opening when the primary pressure reaches the relief pressure.

  The brake valve 71 is disposed on a brake line 55D that constitutes a part of the bleed offline 55C. In the present embodiment, the brake valve 71 is a flow control valve (electromagnetic proportional valve) as shown in FIG. The brake valve 71 blocks the flow of the hydraulic oil in the brake line 55D when the turning body 20 is turned by the turning motor 20. On the other hand, when a brake operation is performed on the swing body 10, the brake valve 71 adjusts the flow rate of hydraulic oil in the brake line 55 </ b> D in accordance with a command signal received from the controller 80 described later, thereby Adjust the brake pressure.

  The brake valve 71 forms an opening that allows the hydraulic oil to flow through the brake line 55D (bleed offline 55C). The brake valve 71 operates so as to change the flow rate of the hydraulic oil passing through the opening by changing the opening area of the opening.

  The brake adjustment device 90 has a function of outputting, to the controller 80, an adjustment amount for adjusting the braking force applied to the turning motor 20 according to the operator's preferred operation feeling. The brake adjustment device 90 is disposed in the cab 12 (FIG. 1), and includes an operation dial, a trimmer (not shown), and the like.

  FIG. 3 is an electrical block diagram of the controller 80 (control unit) of the turning drive device 100 according to the present embodiment. The controller 80 comprehensively controls the operation of the crane 1 and is electrically connected to the rotational speed sensor 20S, the operation lever 56, the brake adjustment device 90, the hydraulic pump 52, the brake valve 71, and the like as transmission destinations of control signals. It is connected. The controller 80 is also electrically connected to other units provided in the crane 1.

  The controller 80 includes a CPU (Central Processing Unit), a ROM (Read Only Memory) that stores a control program, a RAM (Random Access Memory) that is used as a work area of the CPU, and the CPU executes the control program. Thus, the brake state determination unit 81, the hydraulic pump control unit 82 (pump control unit), the brake valve control unit 83, the brake amount calculation unit 84, and the storage unit 85 are functionally operated.

  The brake state determination unit 81 determines whether or not a brake command for the turning motor 20 is input through the rotational speed sensor 20S and the operation lever 56.

  The hydraulic pump control unit 82 changes the capacity (displacement volume) of the hydraulic pump 52 by outputting a pump command signal to the regulator of the variable displacement hydraulic pump 52. As a result, the pump discharge flow rate Qp, which is the flow rate of the hydraulic oil discharged from the hydraulic pump 52, changes.

  The brake valve control unit 83 performs a first turning operation (left turning), a second turning operation (right turning), a first brake operation (left turning brake), and a second brake operation (right turning brake) with respect to the turning motor 20. Is input to the operating lever 56, the opening area of the opening of the brake valve 71 is switched.

  The brake amount calculation unit 84 calculates a brake pressure (brake amount) for the turning motor 20 according to an operation amount input to the operation lever 56 and the like.

  The storage unit 85 stores in advance various parameters referred to by the brake state determination unit 81, the hydraulic pump control unit 82, the brake valve control unit 83, and the brake amount calculation unit 84.

  FIG. 4 is a diagram showing a part of the hydraulic circuit diagram of FIG. 2 when the swing body 10 of the crane 1 according to the present embodiment receives a brake command.

<Adjustment of brake force>
With reference to FIGS. 2 and 4, the operation of the turning drive device 100 when a brake instruction is issued to the turning motor 20 in a state where the turning motor 20 is rotated in a predetermined direction will be described. As described above, the turning drive device 100 includes the rotation speed sensor 20S (FIG. 2). Therefore, when the rotation direction of the swing motor 20 detected by the rotation speed sensor 20S and the operation direction (operation region) received by the operation lever 56 (FIG. 2) are different, the brake state determination unit 81 of the controller 80 It can be determined that the brake operation for 20 (revolving body 10) has been input.

  More specifically, in FIG. 2, when the operation lever 56 is operated in the first operation region S <b> 1 for turning the revolving body 10 in the left direction in a state where the revolving operation of the revolving body 10 is stopped, the operation lever 56 turns left. The pilot pressure of the left turning pilot port 53A is changed via the command line 57A. The operation information is also output to the brake state determination unit 81 of the controller 80. Then, the control valve 54 is switched to the left turning position 54A. At this time, when the rotation direction (turning direction) of the turning motor 20 detected by the rotation speed sensor 20S is the left direction, the brake state determination unit 81 determines that the turning motor 20 has received a normal driving operation (turning operation). To do. On the other hand, when the rotation direction of the swing motor 20 is the right direction, the brake state determination unit 81 determines that the swing motor 20 is receiving a brake operation. That is, the brake state determination unit 81 determines the brake state (deceleration state) when the operation direction received by the operation lever 56 and the rotation direction of the turning motor 20 are opposite.

  About the determination of the brake state by the brake state determination unit 81 as described above, hysteresis is provided in the determination threshold for each detection value in order to prevent the determination from being vibrated due to noise or the like and causing control instability. May be. Specifically, in the determination of the turning state using the rotation speed sensor 20S, the rotation speed 0 (zero) of the rotation motor 20 is set as a threshold value, and the brake state determination unit 81 determines the detection speed of the rotation speed sensor 20S and the threshold value. , The rotational direction of the turning motor 20 may be determined. In addition, when a threshold value of an arbitrary rotation speed is set in advance and the detection speed of the rotation speed sensor 20S is equal to or less than the threshold value, the brake state determination unit 81 determines that the neutral state is established, and the detection speed of the rotation speed sensor 20S is When the threshold value is exceeded, the brake state determination unit 81 may determine that the turning motor 20 is rotating in a predetermined direction. Further, the threshold value may be set to a different value between when the neutral state is switched to the rotational state and when the rotational state is switched to the neutral state.

  Furthermore, also in the determination of the operation direction of the operation lever 56, the brake state determination unit 81 may determine the operation direction using the operation amount 0 (zero) of the operation lever 56 as a threshold value, or a threshold value of an arbitrary operation amount in advance. Is set, and it is determined that the operation amount received by the operation lever 56 is in a non-operation state in a range equal to or less than the threshold value. You may judge. Further, the threshold value may be set to a different value between when the non-operation state is switched to the operation state and when the operation state is switched to the non-operation state.

  In the normal turning operation of the swing body 10, for example, when the operation lever 56 is operated from the neutral operation area SS to the first operation area S1 and the swing body 10 is turning leftward, the control valve 54 is turned to the left turning position. 54A is set. In order to brake the revolving structure 10 from this state, the operator operates the operation lever 56 from the first operation area S1 to the second operation area S2 via the neutral operation area SS. When the turning body 10 is turning leftward, hydraulic fluid is supplied from the first supply line 55A to the motor first port 20A, and hydraulic oil is discharged from the motor second port 20B of the rotary motor 20. In the course of the brake operation, when the operation lever 56 is temporarily positioned in the neutral operation region SS, the control valve 54 is set to the neutral position 54B. In this case, the hydraulic oil discharged from the turning motor 20 flows into the motor first port 20A of the turning motor 20 from the second supply line 55B via the openings B2 and B1 of the control valve 54. A part of the hydraulic oil discharged from the hydraulic pump 52 can be discharged to the tank via the brake line 55D, the opening B3, and the downstream portion of the bleed offline 55C. However, in the state where the operation lever 56 is set to the neutral operation region SS, the opening areas of the openings B1, B2 and B3 are set large, so that the pressure loss of the hydraulic oil is small and the brake motor 20 has a large braking force. There is no effect. As a result, the turning motor 20 continues to rotate due to inertia. At this time, the brake valve control unit 83 controls the opening operation of the brake valve 71 so that the opening of the brake valve 71 is maximized, so that the brake valve 71 may affect the rotational behavior of the swing motor 20. Deterred.

  In the course of the brake operation described above, when the operator further operates the operation lever 56 from the neutral operation region SS to the second operation region S2, the control valve 54 is set to the right turn position 54C. As a result, a braking operation is performed on the revolving structure 10 that is turning leftward. The control valve 54 is gradually switched from the neutral position 54B to the right turning position 54C. At this time, each oil path between the turning motor 20 and the hydraulic pump 52 in FIG. 2 can be modeled as shown in FIG. That is, referring to FIG. 4, according to the operation of operation lever 56, opening B1 of control valve 54 is closed and opening B2 is switched to opening C2. Further, the opening B3 is switched to the opening C3, and the opening C1 is opened.

  The hydraulic oil discharged from the turning motor 20 passes through the opening B2 (C2) from the second supply line 55B and flows into the discharge line of the hydraulic pump 52, and then merges with the hydraulic oil discharged by the hydraulic pump 52. Part of the joined hydraulic oil passes through the opening B1 and flows into the turning motor 20 from the first supply line 55A. However, since the opening B1 is gradually closed, a pressure loss occurs. Further, the remainder of the joined hydraulic oil passes through the brake valve 71 and the opening B3 (C3) and is discharged from the bleed offline 55C to the tank.

  Here, as shown in FIG. 4, between the hydraulic pump 52 and the control valve 54 in the hydraulic oil passage, upstream of the branch points of the first supply line 55 </ b> A and the second supply line 55 </ b> B. The pressure of hydraulic oil (pump downstream pressure) is Pp (MPa), the suction side pressure of the swing motor 20 is P1 (MPa), the discharge side pressure of the swing motor 20 is P2 (MPa), and the pressure of the bleed offline 55C is Pr ( MPa). Further, the differential pressure in the opening B2 (opening C2) is defined as ΔPb2 (Mpa). Since the opening area of the opening B2 (opening C2) is set to be relatively large, it may be assumed that ΔPb2 is sufficiently small. For this reason, the discharge side pressure P2 of the turning motor 20 satisfies the following formula 1.

  As a result, the differential pressure (motor differential pressure ΔPm) between the motor first port 20A side and the motor second port 20B side of the swing motor 20 is derived by the following equation 2.

  Furthermore, when the capacity of the swing motor 20 is defined as qm (cc), the motor torque Tm of the swing motor 20 is derived by the following equation (3).

  From Equation 3, it is possible to control the braking force Tm applied to the swing motor 20 by changing the value of the motor differential pressure ΔPm of the swing motor 20. The motor differential pressure ΔPm can be changed by adjusting the pump downstream pressure Pp (Equation 2). Here, the pressures P1 and Pr are lower than the pressures P2 and Pp during the braking operation, and their fluctuation amounts are small. Thus, these pressures may be regarded as preset constants and may be approximated to zero.

  Next, a method for controlling the brake valve 71 will be described. The hydraulic oil discharge flow rate of the swing motor 20 is defined as Qm (L / min), and the hydraulic oil discharge flow rate of the hydraulic pump 52 is defined as Qp (L / min). Further, the rotation speed of the swing motor 20 is defined as Nm (rpm), and the rotation speed of the hydraulic pump 52 is defined as Np (rpm). At this time, the discharge flow rate Qm of the swing motor 20 and the discharge flow rate Qp of the hydraulic pump 52 are derived by the following equations 4 and 5. Note that qp (cc) is a pump capacity of the hydraulic pump 52.

  Further, when the target pressure of the pump downstream pressure Pp is defined as Pt, the flow rate Qb1 of the hydraulic oil that passes through the opening B1 in the target state is derived by the following Expression 6.

Cv is a flow coefficient of hydraulic oil, Ab1 is an opening area (mm ² ) of the opening B1, and is stored in the storage unit 85 as a known value. Furthermore, the flow rate Qb3 of the hydraulic oil that passes through the opening B3 in the target state is derived by the following expression 7.

Here, as described above, the pressures P1 and Pr are lower than the pressures P2 and Pp during the braking operation, and their fluctuation amounts are small. Thus, these pressures may be regarded as preset constants and may be approximated to zero. On the other hand, the differential pressure ΔP3 (MPa) generated at the opening B3 (C3) in the target state is derived by the following formula 8 when the opening area of the opening B3 (C3) is defined as Ab3 (mm ² ).

  Ab3 is stored in advance in the storage unit 85 as a known value. From the above, the brake valve control pressure ΔPk generated in the brake valve 71 is derived from Equation 9 below.

In the above, the pressure Pr of the bleed offline 55C can be regarded as a constant or zero. Using this brake valve control pressure ΔPk, the opening area Ak (mm ² ) of the bleed-off valve 71 is derived by the following equation (10).

  As described above, by adjusting the opening area Ak of the brake valve 71, the motor differential pressure ΔPm is set to Pt−P1 by the target pressure Pt and the pressure P1 from Equation 2 (the differential pressure ΔPb2 is regarded as zero), and turning A target braking force can be applied to the motor 20. That is, in the present embodiment, by setting the pump downstream pressure Pp to the target pressure Pt, the motor differential pressure ΔPm is adjusted and a target braking force is applied. Then, the opening area Ak of the brake valve 71 is adjusted in order to set the pump downstream pressure Pp to the target pressure Pt. Here, since Expression 7 includes the discharge flow rate Qm of the swing motor 20, the opening area Ak of the brake valve 71 can be set so as to cancel the influence of the rotational speed of the swing motor 20 on the braking force. it can.

<Brake processing flow>
FIG. 5 is a flowchart in the case where the swing body 10 of the crane 1 according to the present embodiment undergoes a braking operation. With reference to FIG. 5, the processing flow of the brake operation of the turning motor 20 will be described. When the crane 1 is used, the brake state determination unit 81 (FIG. 3) of the controller 80 determines the brake state of the turning motor 20 (step S1). That is, the operation lever 56 operates from the first operation area S1 to the second operation area S2 via the neutral operation area SS (first brake) while the turning motor 20 is turning leftward (first direction). Operation lever 56 or when the turning motor 20 is turning in the right direction (second direction), the operation lever 56 passes from the second operation region S2 via the operation intermediate region SS to the first operation region S1. The brake state determination unit 81 determines that the turning motor 20 is in the brake state (YES in step S1).

  Next, the brake amount calculation unit 84 of the controller 80 calculates the discharge flow rate Qm of the swing motor 20 based on Equation 4 from the rotation speed (the number of rotations Nm) of the swing motor 20 (step S2).

  Next, the brake amount calculation unit 84 determines the brake valve control pressure ΔPk generated in the brake valve 71 (step S3 in FIG. 5). At this time, the brake amount calculation unit 84 acquires the target pressure Pt and the pressures P1 and Pr stored in the storage unit 85. FIG. 6 is a graph showing the relationship between the operation amount of the operation lever 56 (lever operation amount R), the motor rotation speed M, and the target pressure Pt. Information on the target pressure Pt as shown in FIG. 6 is stored in the storage unit 85 in advance. The target pressure Pt is set according to the operation amount R of the operation lever 56 and the rotation speed M (or the rotation speed Nm) of the turning motor 20. In particular, as shown in FIG. 6, the target pressure Pt is set to be larger as the rotational speed of the swing motor 20 is higher, so that excessive braking force is prevented from being applied to the swing motor 20. Then, the brake amount calculation unit 84 calculates a brake valve control pressure ΔPk (differential pressure) based on the acquired pressures P1 and Pr and the target pressure Pt.

  Next, the brake amount calculation unit 84 calculates the opening area Ak of the brake valve 71 (brake valve opening area Ak) (step S4). Then, the brake amount calculation unit 84 calculates the opening area Ak (brake valve opening area Ak) of the brake valve 71 based on Expressions 4 to 10.

  As a result, the brake valve control unit 83 controls the brake valve 71 to adjust the opening area of the opening (step S5). If it is determined in step S1 of FIG. 5 that the turning motor 20 is not in the brake state (NO in step S1), the brake valve control unit 83 sets the opening area of the brake valve 71 to the maximum area. As a result, the opening of the brake valve 71 is fully opened (step S6).

  As described above, in this embodiment, the brake valve control unit 83 opens the opening of the brake valve 71 so that the pump downstream pressure Pp becomes the predetermined target pressure Pt corresponding to the operation amount that the operation lever 56 receives. The brake valve 71 generates a pressure loss in the hydraulic oil. As a result, even if the discharge flow rate Qm of the swing motor 20 or the discharge flow rate Qp of the hydraulic pump 52 changes during the operation of the crane 1 according to the rotational speed of the swing motor 20, the operation lever A desired braking force can be applied to the turning motor 20 according to the operation amount of 56.

  In particular, in the present embodiment, the brake valve 71 is a flow control valve capable of adjusting the opening area so that the opening area of the opening continuously changes. And the brake valve control part 83 adjusts the opening area of the brake valve 71 so that the differential pressure | voltage of the turning motor 20 may turn into target pressure Pt, when the operation lever 56 receives brake operation. As a result, the flow rate of the hydraulic oil passing through the opening of the brake valve 71 can be adjusted with high accuracy, and the braking force applied to the turning motor 20 can be adjusted smoothly according to the operation of the operation lever 56. It becomes possible.

  In the above description, the brake force of the swing motor 20 is adjusted according to the target pressure Pt stored in advance in the storage unit 85 (FIG. 3) as shown in FIG. The force may be further adjusted to the desired magnitude. 7 and 8 are graphs showing the relationship between the lever operation amount R of the operation lever 56 and the target pressure Pt in the turning drive device 100, respectively. When the operator operates the brake adjustment device 90 in the cab 12, the brake amount calculation unit 84 corrects the value of the target pressure Pt when the brake is operated. In FIG. 7, when the operator adjusts the brake adjustment device 90 to the brake force increase side, the target pressure Pt increases as the lever operation amount R increases. On the other hand, when the operator adjusts the brake adjustment device 90 to the brake force down side, the target pressure Pt decreases as the lever operation amount R increases. On the other hand, in FIG. 8, the braking force can be largely corrected near the center of the lever operation amount R. The target pressure Pt corrected in this way is referred to in Steps S2 and S3 in FIG. 5 (Formula 6 and Formula 9).

Second Embodiment
Next, a second embodiment of the present invention will be described. FIG. 9 is a diagram showing a hydraulic circuit diagram of the turning drive device 100A of the crane 1 according to the present embodiment. Since the present embodiment is different from the first embodiment in the configuration of the control valve 54 and the arrangement of the brake valve 71, the difference will be described.

  In the present embodiment, as shown in FIG. 9, the control valve 54 does not include the openings A3, B3, and C3 of FIG. The bleed offline 55C does not include the brake line 55D described above. The brake valve 71 is disposed on the bleed offline 55C between the joining position where the first supply line 55A and the second supply line 55B join and the tank. Even in such a configuration, when the brake operation of the swing body 10 is commanded during the operation of the crane 1, the opening of the brake valve 71 is adjusted, and the bleed offline 55 </ b> C responds to the return oil from the swing motor 20. Pressure loss. Even if the discharge flow rate Qm of the swing motor 20 or the discharge flow rate Qp of the hydraulic pump 52 changes according to the rotation speed of the swing motor 20 with respect to the brake operation, the operation lever 56 is operated. A desired braking force corresponding to the operation amount can be applied to the turning motor 20.

<Third Embodiment>
Next, a third embodiment of the present invention will be described. FIG. 10 is a diagram showing a hydraulic circuit diagram of the turning drive device 100 of the crane 1 according to the present embodiment. Since the present embodiment is different from the second embodiment in the structure of the brake valve 72, the difference will be described.

  In the present embodiment, the brake valve 72 is a variable relief valve. Specifically, the variable relief valve opens when the primary pressure reaches the relief pressure, thereby maintaining the primary pressure at a pressure equal to or lower than the relief pressure and changing the relief pressure by inputting a command signal from the outside. It is configured to be possible. The brake valve 72 performs a valve opening operation so that the pressure (pressure Pp) between the opening of the brake valve 72 and the hydraulic pump 52 in the bleed offline 55C is kept below a predetermined relief pressure. The relief pressure of the brake valve 72 is controlled by the brake valve control unit 83 of the controller 80.

  In the present embodiment, the brake valve controller 83 (FIG. 3) of the controller 80 determines that the differential pressure of the swing motor 20 is the target pressure Pt when the operation lever 56 is subjected to the first brake operation or the second brake operation. The relief pressure of the brake valve 72 is adjusted so that As a result, even if the discharge flow rate Qm of the swing motor 20 or the discharge flow rate Qp of the hydraulic pump 52 changes during the operation of the crane 1 according to the rotational speed of the swing motor 20, the operation lever A desired braking force corresponding to the operation amount of 56 can be applied to the turning motor 20.

<Fourth embodiment>
Next, a fourth embodiment of the present invention will be described. FIG. 11 is a flowchart when the swing body 10 of the crane 1 according to the present embodiment undergoes a braking operation in the configuration of FIG. Since the present embodiment differs from the first embodiment in the capacity reduction control of the hydraulic pump 52 in the processing flow of the brake operation, the difference will be described.

  In the present embodiment, when the brake state determination unit 81 (FIG. 3) of the controller 80 determines that the swing motor 20 is in a brake state (YES in step S11), the hydraulic pump control unit 82 (FIG. 3) The pump capacity qp of the hydraulic pump 52 is made smaller than when the 10 is turned in the first direction or the second direction (first turning operation, second turning operation) (step S12). Here, the load power W to the engine that drives the hydraulic pump 52 is derived by the following equation (11).

  Here, Np is the rotational speed of the hydraulic pump 52. Therefore, energy saving of the crane 1 can be realized by setting the pump capacity qp to be small at the time of a brake operation that does not require the active hydraulic oil to be supplied to the swing motor 20. Note that steps S13 to S16 in FIG. 11 are the same as steps S2 to S5 in FIG. When the brake state determination unit 81 determines that the swing motor 20 is not in the brake state in step S11, the opening area of the opening of the brake valve 71 is adjusted to the maximum area, and the opening of the brake valve 71 is fully opened. (Step S18).

<Fifth Embodiment>
Next, a fifth embodiment of the present invention will be described. FIG. 12 is a flowchart when the swing body 10 of the crane 1 according to the present embodiment is subjected to a braking operation in the configuration of FIG. 2, and FIG. 13 is a flowchart showing in detail the content of step S24 of FIG. . Since the present embodiment differs from the fourth embodiment in the method for setting the target pressure Pt in the brake operation processing flow, the difference will be mainly described.

  In the fourth embodiment described above, energy saving of the crane 1 is realized by setting the pump capacity qp of the hydraulic pump 52 to be small during the braking operation of the swing motor 20. However, when the pump capacity qp is set to be small, the flow rate of hydraulic oil (Qb3 in FIG. 4) in the bleed offline 55C decreases. As a result, the pressure loss of the hydraulic oil generated in the bleed offline 55C decreases, so that the pump downstream pressure Pp decreases and the braking force applied to the turning motor 20 decreases. In the present embodiment, a high target pressure Pt (assist target pressure Pta) is set so as to compensate for this decrease in braking force. In step S22 of FIG. 12, when the hydraulic pump control unit 82 decreases the pump capacity qp of the hydraulic pump 52, the discharge capacity Qm of the turning motor 20 is calculated (step S23) as in step S2 of FIG. The assist target pressure Pta is calculated (step S24). After the assist target pressure Pta is calculated, the opening area of the brake valve 71 is calculated in steps S25 to S27, and then the opening of the brake valve 71 is adjusted.

  A setting flow of the assist target pressure Pta will be described with reference to FIG. Here, as an example, in the case where the turning drive device 100 does not include the brake valve 71, the brake force equivalent to the case where the pump capacity qp is not reduced (the brake sensation familiar to the operator in the prior art) is turned. An assist target pressure Pta for setting the motor 20 is calculated.

  When the calculation flow of the assist target pressure Pta is started (step S24), the brake amount calculation unit 84 (FIG. 3) calculates a reference bleed offline flow rate Qb3 '(L / min) (step S241). Here, the reference bleed offline flow rate Qb3 'is the flow rate of the hydraulic oil flowing through the bleed offline 55C based on the discharge flow rate Qp' of the hydraulic pump 52 corresponding to the pump capacity qp 'before being lowered in step S22. The reference bleed offline flow rate Qb3 'is calculated by the following equation 12 using the opening area Ab1 of the opening B1 and the opening area Ab3 of the opening B3.

  For the discharge flow rate Qm, the calculation result of step S23 is referred to. The pressure P1 and the pressure Pr may be regarded as zero or a constant, and may be measured by a pressure gauge (not shown). Further, Qp ′ in Expression 12 is calculated by Expression 13 below. Np is the rotational speed of the hydraulic pump 52.

  Next, the brake valve control unit 83 calculates the assist target pressure Pta (step S242). The assist target pressure Pta corresponds to a pressure loss that occurs in the opening B3 (bleed-off opening) when the hydraulic pump 52 is set to the pump displacement qp ′. The assist target pressure Pta is calculated by the following formula 14.

  For the reference bleed offline flow rate Qb3 ', the calculation result of step S241 is referred to. The flow coefficient Cv and the opening area Ab3 are stored in advance in the storage unit 85 (FIG. 3). Further, as described above, the pressure Pr of the bleed offline 55C may be regarded as zero or a constant, and may be measured by a pressure gauge (not shown).

  When the assist target pressure Pta is calculated in step S24 (S241 to S242), the pressure (brake valve control pressure ΔPk) generated in the brake valve 71 is calculated in step S25 of FIG. At this time, the brake valve control unit 83 calculates the flow rate Qb1 (L / min) of the hydraulic oil that passes through the opening B1 in the target state using the following Expression 15.

  Further, the pressure ΔPk is calculated using the following equation (16).

  The assist target pressure Pta is referred to the calculation result in step S242. Thereafter, as in the previous embodiment, the opening area of the opening of the brake valve 71 is calculated and the opening of the opening is adjusted in steps S26 and S27 of FIG.

  Thus, in the present embodiment, during the braking operation of the swing motor 20, the assist target pressure Pta is set so as to prevent or compensate for the decrease in brake force accompanying the decrease in the pump capacity qp of the hydraulic pump 52, The opening area of the opening of the brake valve 71 is adjusted. For this reason, energy saving of the crane 1 and the brake operation according to the operation amount of the operation lever 56 can be made compatible.

  Note that the brake state determination unit 81 determines that the brake operation on the operation lever 56 has been released after the decrease in the brake force accompanying the decrease in the pump capacity qp of the hydraulic pump 52 is suppressed as in the present embodiment. Then, the hydraulic pump control unit 82 restores (increases) the pump capacity qp of the hydraulic pump 52, and the brake valve control unit 83 fully opens the brake valve 71. At this time, if there is a difference in responsiveness between the hydraulic pump 52 and the brake valve 71, the brake valve 71 is fully opened before the pump capacity qp of the hydraulic pump 52 has fully returned, and the braking force at the brake valve 71 becomes transient. May be reduced. Therefore, when the determination of the deceleration state (brake operation) in the swing motor 20 is released, it is desirable to cause a predetermined delay (time difference) in the opening operation of the brake valve 71 rather than the capacity increase command to the hydraulic pump 52. .

  Specifically, when the operation lever 56 receives an operation from the second operation region S2 to the neutral operation region SS after the first brake operation, the brake state determination unit 81 determines that the first brake release operation has been executed. Similarly, when the operation lever 56 receives an operation from the first operation region S1 to the neutral operation region SS after the second brake operation, the brake state determination unit 81 determines that the second brake release operation has been executed. As a result, the hydraulic pump control unit 82 starts a pump capacity return operation that increases the capacity of the hydraulic pump 52 that is reduced when the first brake operation or the second brake operation is performed. Further, the brake valve control unit 83 adjusts the flow rate of the hydraulic oil that passes through the opening of the brake valve 71 to reduce the hydraulic oil pressure loss generated in the brake valve 71 from the start of the pump capacity return operation. The brake release operation is performed so as to disappear after the elapse of time (for example, 0.1 sec). At this time, the brake valve control unit 83 outputs a command signal to the brake valve 71 after a predetermined time has elapsed from the start of the pump capacity return operation. The time difference until the command signal is output may be set according to the balance of responsiveness of each device. For example, the time difference may be set based on the first-order lag characteristic, and change per time like a rate limiter. It may be set based on a characteristic that limits the amount linearly. In either case, control is performed such that the brake valve 71 is completely opened after a predetermined time has elapsed since the capacity of the hydraulic pump 52 began to return.

  By such control, even when a predetermined time (response delay) is required to increase the pump capacity qp of the hydraulic pump 52 in the pump capacity return operation, the pump valve qp is generated in the brake valve 71 before the pump capacity qp increases. The disappearance of the pressure loss that has been performed is suppressed, in other words, the brake valve 71 is suppressed from being fully opened. As a result, a phenomenon in which the brake pressure of the brake valve 71 decreases transiently can be prevented. The brake state determination unit 81 may determine that the brake operation has been released based on a change in the turning speed of the turning motor 20.

  In the fourth embodiment and the fifth embodiment described above, the braking force for the swing body 10 decreases as the pump capacity qp of the hydraulic pump 52 decreases. In other words, the brake force setting region for the swing body 10 is set. (Lower limit) can be widened. Therefore, when it is desired to set the brake force on the swing body 10 small (see the brake force down in FIGS. 7 and 8), the hydraulic pump control unit 82 is configured to operate the hydraulic pump 52 in comparison with the normal swing operation. You may perform control which sets pump capacity qp small.

<Sixth Embodiment>
Next, a sixth embodiment of the present invention will be described. Since the present embodiment is different from the first embodiment in that the pressure sensor 52P is used, the difference will be mainly described and description of common points will be omitted. As described above, the turning drive device 100 according to the present embodiment further includes the pressure sensor 52P (pressure detection unit). The pressure sensor 52P is disposed between the hydraulic pump 52 and the control valve 54 in the hydraulic oil passage, and detects the hydraulic oil pressure (the aforementioned pump downstream pressure Pp). Further, as shown in FIG. 3, the controller 80 described above is connected to the pressure sensor 52P. Further, the brake amount calculation unit 84 calculates the brake pressure (brake amount) for the swing motor 20 according to the operation amount input to the operation lever 56, the pump downstream pressure Pp detected by the pressure sensor 52P, and the like.

  In the first embodiment described above, the target pressure Pt of the pump downstream pressure Pp is substituted in Formula 6, but in this embodiment, the pump downstream pressure Pp detected by the pressure sensor 52P is calculated. , Pt is substituted into Equation 6. In the first embodiment, the opening area Ak of the bleed-off valve 71 is directly calculated and adjusted in order to obtain a desired target value Pt. On the other hand, in the present embodiment, the actual pump downstream pressure Pp is measured, and the opening area Ak of the bleed-off valve 71 is calculated and adjusted based on the pump downstream pressure Pp. For this reason, as compared with the first embodiment, there is a slight delay in adjusting the opening area Ak of the bleed-off valve 71. However, in construction machines such as the crane 1, in order to confirm the operation status of the hydraulic pump 52, the pressure sensor 52 </ b> P is often provided in advance. For this reason, the opening area Ak of the bleed-off valve 71 can be adjusted using the detection result of the pressure sensor 52P. Further, as compared with the first embodiment, it is possible to reduce the need to secure an area for storing many target values Pt in the storage unit 85 (FIG. 3). Also in the present embodiment, the motor differential pressure ΔPm is adjusted to the target pressure based on the pump downstream pressure Pp, and the target braking force is applied to the swing motor 20. Moreover, you may apply the aspect which concerns on previous 2nd-5th embodiment to this embodiment.

<Seventh embodiment>
Next, a seventh embodiment of the present invention will be described. Since this embodiment is different from the previous first embodiment in that the motor differential pressure is detected by the pressure sensor, the difference will be mainly described, and the description of the common points will be omitted. Referring to FIG. 4, in the present embodiment, in the hydraulic circuit of the first embodiment, pressure sensors (not shown) that measure the pressure P1 and the pressure P2 in FIG. 4 are respectively used as the first supply line 55A and the second supply line. 55B. As a result, the motor differential pressure ΔPm upstream and downstream of the swing motor 20 can be measured.

  In the present embodiment, the following formulas 17 and 18 can be used instead of the formulas 6 and 9 in the first embodiment. When the target pressure of the motor differential pressure ΔPm is defined as Pt, the flow rate Qb1 of hydraulic fluid that passes through the opening B1 in the target state is derived by Expression 17.

  Further, the brake valve control pressure ΔPk generated in the brake valve 71 is derived from Expression 18. Note that ΔP3 is derived from Equation 8 described above.

  Further, in both Expression 17 and Expression 18, the differential pressure ΔPb2 (Mpa) at the opening B2 (opening C2) is derived by Expression 19 below. If the area Ab2 of the opening B2 is sufficiently large, ΔPb2 can be regarded as zero.

Using the brake valve control pressure ΔPk derived from Equation 18, the opening area Ak (mm ² ) of the bleed-off valve 71 is derived from Equation 10 described above.

  As described above, also in this embodiment, by adjusting the opening area Ak of the brake valve 71, the motor differential pressure ΔPm is set to Pt, and the target braking force can be applied to the swing motor 20. That is, in this embodiment, the pressures P1 and P2 constituting the motor differential pressure ΔPm of the swing motor 20 are measured by the respective pressure sensors, so that the motor differential pressure ΔPm is adjusted to a value corresponding to the operation amount of the operation lever 56 The target braking force is applied. Then, since the motor differential pressure ΔPm is set to a target value, the opening area Ak of the brake valve 71 is adjusted. Here, since the discharge flow rate Qm of the swing motor 20 is included in Equation 19, the opening area Ak of the brake valve 71 can be set so as to cancel the influence of the rotational speed of the swing motor 20 on the braking force. it can.

  Also in the present embodiment, control using the assist target pressure Pta in the fifth embodiment can be applied in addition to the fourth embodiment described above. At this time, for calculating the assist target pressure Pta, the following equation 20 can be used instead of the aforementioned equation 14.

  According to such control, the assist target pressure Pta is set and the brake target is set so as to prevent or compensate for the decrease in the brake force accompanying the decrease in the pump capacity qp of the hydraulic pump 52 during the brake operation of the swing motor 20. The opening area of the opening of the valve 71 is adjusted. For this reason, energy saving of the crane 1 and the brake operation according to the operation amount of the operation lever 56 can be made compatible.

<Eighth Embodiment>
Next, an eighth embodiment of the present invention will be described. FIG. 14 is a hydraulic circuit diagram of the turning drive device for the work machine according to the present embodiment. FIG. 15 is a diagram illustrating a part of the hydraulic circuit diagram of the turning drive device of FIG. 14 when the turning body of the work machine according to the present embodiment receives a braking operation. FIG. 16 is a view showing a part of the hydraulic circuit diagram of the turning drive device of FIG. 14 when the turning body of the working machine according to the present embodiment receives a braking operation. 15 mainly shows the open / close state of each valve, and FIG. 16 mainly shows the pressure (differential pressure) of the hydraulic oil in each valve. Since the present embodiment is different from the first embodiment in the structure of the control valve 54, the difference will be mainly described. Further, in the present embodiment, the pressure sensor 52P is not necessary as in the first embodiment.

  As in the first embodiment, the control valve 54 is configured by an electromagnetic switching type directional switching valve (solenoid valve) in the present embodiment, and a left turn position according to a switching signal input to the control valve 54. It operates to switch between 54A (first turning position), neutral position 54B (neutral turning position) and right turning position 54C (second turning position). The control valve 54 has a pair of pilot ports, that is, a left turning pilot port 53A and a right turning pilot port 53B. The control valve 54 is maintained at the neutral position 54B when no pilot pressure is input to either the left turning pilot port 53A or the right turning pilot port B. The control valve 54 is switched to the left turn position 54A when the pilot pressure is input to the left turn pilot port 53A, and is switched to the right turn position 54C when the pilot pressure is input to the right turn pilot port 53B. The control valve 54 is opened with an opening area corresponding to the pilot pressure, and changes the flow rate of the hydraulic oil.

  At the left turning position 54A, the control valve 54 supplies hydraulic oil discharged from the hydraulic pump 52 to the motor first port 20A through the first supply line 55A and bleeds hydraulic oil discharged from the motor second port 20B. An oil passage leading to the tank through the offline 55C is formed. In addition to the openings A1, A2, and A3, A4 is formed at the left turning position 54A. At the right turning position 54C, the control valve 54 supplies the hydraulic oil discharged from the hydraulic pump 52 to the motor second port 20B through the second supply line 55B, and the hydraulic oil discharged from the motor first port 20A. An oil passage leading to the tank through the bleed offline 55C is formed. In addition to the openings C1, C2, and C3, C4 is formed at the right turn position 54C. In the neutral position 54B, the control valve 54 causes the hydraulic oil to circulate between the motor first port 20A and the motor second port 20B by connecting the first supply line 55A and the second supply line 55B to each other. Allow that. In the neutral position 54B, B4 and B5 are formed in addition to the openings B1, B2, and B3. Further, as described above, in this embodiment, the pressure sensor 52P is not provided. 15 and 16, the pressure Pp is shown, but the pressure Pp is virtually shown for each calculation. The other structure of the turning drive device 100 is the same as that shown in FIG.

  In the first embodiment, when the control valve 54 is set to the left turning position 54A, the C1 line formed at the right turning position 54C is closed. Similarly, when the control valve 54 is set to the right turning position 54C, the A2 line formed at the left turning position 54A is closed. When the control valve 54 is set to the neutral position 54B, the C1 line and the A2 line are closed. On the other hand, in the present embodiment, when the control valve 54 is set to the left turning position 54A, the C1 line is opened through the A4 line. Similarly, when the control valve 54 is set to the right turning position 54C, the A2 line is opened through the C4 line. Further, when the control valve 54 is set to the neutral position 54B, the C1 line and the A2 line are opened through the B4 and B5 lines.

  Also in the configuration of the control valve 54 and the brake valve 71 shown in FIG. 14, the opening area Ak of the brake valve 71 can be derived by the brake valve control unit 83.

  Also in the present embodiment, in the normal turning operation of the swing body 10, for example, when the operation lever 56 is operated from the neutral operation area SS to the first operation area S 1 and the swing body 10 is turning leftward, the control valve 54. Is set to the left turning position 54A. In order to brake the revolving structure 10 from this state, the operator operates the operation lever 56 from the first operation area S1 to the second operation area S2 via the neutral operation area SS. As a result, the control valve 54 is set to the right turning position 54C, and the braking operation for the turning body 10 turning left is executed. At this time, since the control valve 54 gradually switches from the neutral position 54B to the right turning position 54C, the oil passages between the turning motor 20 and the hydraulic pump 52 in FIG. Can be modeled. That is, referring to FIG. 15, according to the operation of the operation lever 56, the opening B1 of the control valve 54 is closed and the opening B2 is switched to the opening C2. The opening B3 is switched to the opening C3, and the opening B4 is switched to the opening C1. Further, the opening B5 is switched to the opening C4.

  The hydraulic oil discharged from the turning motor 20 passes through the opening B2 (C2) from the second supply line 55B and flows into the discharge line of the hydraulic pump 52, and then merges with the hydraulic oil discharged by the hydraulic pump 52. Part of the joined hydraulic oil passes through the opening B1 and flows into the turning motor 20 from the first supply line 55A. However, since the opening B1 is gradually closed, a pressure loss occurs. Further, the remainder of the joined hydraulic oil passes through the brake valve 71 and the opening B3 (C3) and is discharged from the bleed offline 55C to the tank. In the present embodiment, part of the hydraulic fluid that has flowed into the control valve 54 from the second supply line 55B can flow into the bleed offline 55C through the opening B5 (C4) without passing through the brake valve 71. . When the control valve 54 reaches the right turning position 54C, the opening B1 is closed as described above, so that the inflow of hydraulic oil from the first supply line 55A to the turning motor 20 is shut off.

15 and 16, in addition to the above-described symbols, the differential pressure of the hydraulic oil at the opening C4 is ΔPc4 (Mpa), the opening area of the opening C4 is Ac4 (mm ² ), and the flow rate of the hydraulic oil passing through the opening C4 is It is defined as Qc4 (L / min). Also in this embodiment, the pressure of the hydraulic oil flowing into the swing motor 20 in the first supply line 55A is P1 (MPa), the pressure of the hydraulic oil discharged from the swing motor 20 is P2 (MPa), and the bleed offline 55C The pressure of hydraulic oil is defined as Pr (MPa), and the discharge pressure of the hydraulic pump 52 is defined as Pp (MPa).

  Referring to FIGS. 14 to 16, it is assumed that an oil passage through which hydraulic oil discharged from the turning motor 20 during the brake operation described above is led to the tank through the control valve 54 is open. In this case, the following Expression 21 is referred to instead of Expression 7.

  Here, the flow rate Qc4 in Expression 21 is derived by Expression 22 below using the opening area Ac4 of the opening C4.

  By applying Formula 21 and Formula 22 to the previous first embodiment, by adjusting the opening area Ak of the brake valve 71 based on Formula 10, a target braking force can be applied to the turning motor 20. .

  Furthermore, in this embodiment, the pump capacity qp of the hydraulic pump 52 is reduced for the purpose of energy saving, as in the fourth embodiment. Further, as in the fifth embodiment, since the brake force equivalent to that when the pump displacement qp is not reduced is set in the turning motor 20, the assist target pressure Pta can be calculated. The derivation process will be described below.

  Also in this process, as shown in FIG. 14, it is assumed that an oil passage through which hydraulic oil discharged from the turning motor 20 during the brake operation is guided to the tank through the control valve 54 is open. In this case, referring to FIG. 16, the following Expression 23 is satisfied from the balance of the discharge pressure Pp of the hydraulic pump 52.

  Again, the pressures ΔPb1 ′, ΔPb3 ′, and ΔPE ′ correspond to the differential pressures in the openings B1 and B3 and the brake valve 71 before the pump capacity qp of the hydraulic pump 52 is set to be small. Also in Equation 23, as in the first embodiment, since it can be considered that P1 = Pr = 0, Equation 24 is derived from Equation 23.

  As before, applying a known orifice equation to equation 24 yields equation 25.

  Cv is a flow coefficient of hydraulic oil. Ab3_new corresponds to the opening area of the combined opening B3_new, in which the opening B3 and the opening of the brake valve 71 (maximum opening area Ae) are virtually regarded as one opening. The opening area Ab3_new is derived by the following expression 26.

  Here, the flow rate Qb <b> 1 ′ of the hydraulic oil passing through the opening B <b> 1 is derived from Equation 27 below.

  Then, by substituting Equation 27 into Equation 26 and rearranging Qb3 ', Equation 28 is derived.

  Next, referring to FIG. 16, the pressure balance between the oil path from the tank to pressure P2 via opening C4 and the oil path from the tank to opening P3 and via brake valves 71 and B2 to pressure P2. Equation 29 is derived from the above.

  Here, as in the first embodiment, assuming ΔPb2 ′ = 0, the following Expression 30 is established.

  Again, using the known orifice equation, replacing Equation 30 and organizing the flow rate Qb3 ', Equation 31 is derived.

  Since both Expression 28 and Expression 31 relate to the flow rate Qb3 ', Expression 32 is established by connecting the right side of each expression with an equal sign.

  Solving Equation 32 for flow rate Qc4 'leads to Equation 33.

  Then, by substituting Expression 33 into Expression 31 and rearranging, Expression 34 is derived.

  Also in the equation 34, the flow rate Qp ′ is calculated from the above-described equation 13, and the flow rate Qm is calculated from the equation 4. Further, the opening areas Ab1 and Ac4 are known, and the opening area Ab3_new is calculated from Expression 26. Before the pump capacity qp of the hydraulic pump 52 is reduced, the flow rate Qb3 'of the hydraulic oil flowing through the opening B3 is calculated from the equation 34. Further, on the premise of the relationship of Expression 23 and P1 = Pr = 0, the pressure Pp on the downstream side of the hydraulic pump 52 before the pump capacity qp of the hydraulic pump 52 is reduced is calculated from the right side of Expression 25. By setting the pressure Pp calculated here as the assist target pressure Pta, it is possible to apply the same braking force to the swing motor 20 as before the pump capacity qp of the hydraulic pump 52 is reduced.

  In the above, the working machine provided with the turning drive device concerning each embodiment of the present invention was explained. The present invention is not limited to these forms. In the present invention, the following modified embodiments are possible.

  (1) In the above embodiment, the operation lever 56 is operated from the first operation region S1 to the second operation region S2 via the neutral operation region SS while the revolving structure 10 is turning leftward. However, the present invention is not limited to this. It may be determined that a brake operation has been input to the swing body 10 by operating the operation lever 56 in the second operation region S2 while the swing body 10 is turning leftward. Further, the brake operation input may be determined by detecting an oil flow in the pilot line connected to the control valve 54 or an input signal to the solenoid by a sensor (not shown).

  (2) In the fifth embodiment described above, the assist target pressure Pta is calculated. However, the assist target pressure Pta is stored in the storage unit 85 in advance as the target pressure Pt in FIG. An aspect may be sufficient.

  (3) Moreover, in said embodiment, although the turning drive apparatus 100 demonstrated in the aspect provided with the brake adjustment apparatus 90, the aspect which is not provided with the brake adjustment apparatus 90 may be sufficient as the turning drive apparatus 100.

1 Crane 10 Revolving body 11 Traveling body (airframe)
20 Rotating motor 20A Motor first port (first port)
20B Motor 2nd port (2nd port)
20S Rotational speed sensor 52 Hydraulic pump 52P Pressure sensor (pressure detector)
53A Left turn pilot port 53B Right turn pilot port 54 Control valve 54A Left turn position (first turn position)
54B Neutral position (neutral turning position)
54C Right turn position (second turn position)
55A First supply line (first oil passage)
55B Second supply line (second oil passage)
55C Bleed Offline (Discharge oil passage)
55D Brake line 56 Operation lever (operated part)
71, 72 Brake valve 80 Controller 81 Brake state determination unit 82 Hydraulic pump control unit 83 Brake valve control unit (brake control unit)
84 Brake Amount Calculation Unit 85 Storage Unit 90 Brake Adjustment Device 100 Turning Drive Device

Claims (7)

A turning drive device provided in a work machine including a machine body and a swing body disposed above the machine body, and configured to drive the swing body to turn relative to the machine body;
A hydraulic swivel motor interposed between the airframe and the swivel body to drive the swivel swivel, the swivel motor having a first port and a second port, wherein the first port The swivel body is swiveled in the first direction by receiving the supply of hydraulic oil through the second port, and the hydraulic oil is discharged through the second port, while the swivel body is moved in the first direction by receiving the supply of hydraulic oil through the second port. A swivel motor that swivels in a second direction opposite to the one direction and discharges hydraulic oil through the first port;
A hydraulic pump that discharges hydraulic oil to be supplied to the swing motor;
A first oil passage communicating the hydraulic pump and the first port of the swing motor;
A second oil passage communicating the hydraulic pump and the second port of the swing motor;
A discharge oil passage which is capable of communicating with the first oil passage and the second oil passage and guides return oil discharged from the turning motor to a tank;
A operated part that is operated for a turning operation of the revolving structure, the first operation region for turning the revolving body in the first direction, and a second operation for turning the revolving body in the second direction. A region and a neutral operation region between the first operation region and the second operation region can be selectively operated, and the operation target in the first operation region and the second operation region The operated part, the operation amount of the part being variable,
A control valve interposed between the hydraulic pump and the swing motor, and supplies hydraulic oil discharged from the hydraulic pump to the first port through the first oil passage and is discharged from the second port. A first turning position for forming an oil passage for guiding the working oil to the tank through the discharge oil passage, and supplying the hydraulic oil discharged from the hydraulic pump to the second port through the second oil passage. The second turning position that forms an oil passage that guides the hydraulic oil discharged from the first port to the tank through the discharge oil passage, and the first oil passage and the second oil passage communicate with each other. A control valve capable of switching to a neutral turning position allowing hydraulic fluid to circulate between the first port and the second port;
A brake valve disposed in the discharge oil passage, which is configured to form an opening that allows the flow of hydraulic oil in the discharge oil passage and to change a flow rate of the hydraulic oil that passes through the opening. Brake valve to
When the operated part receives a first brake operation from the first operation area to the second operation area via the neutral operation area while the revolving body is turning in the first direction, Alternatively, the operated portion receives a second brake operation from the second operation area to the first operation area via the operation intermediate area in a state where the revolving body is turning in the second direction. In this case, the flow rate of the hydraulic oil passing through the opening is adjusted so that the differential pressure of the swing motor becomes a predetermined target pressure corresponding to the operation amount received by the operated portion. And a brake control unit that generates a pressure loss. The brake valve is a flow control valve capable of adjusting an opening area of the opening,
The brake control unit is configured to open the flow control valve so that a differential pressure of the swing motor becomes the target pressure when the operated portion is subjected to the first brake operation or the second brake operation. The turning drive device according to claim 1, wherein an opening area of the portion is adjusted. The brake valve is a variable relief valve that performs a valve opening operation so as to maintain a pressure between the opening and the hydraulic pump in the discharge oil passage below a predetermined relief pressure,
The brake control unit is configured to reduce a relief pressure of the variable relief valve so that a differential pressure of the swing motor becomes the target pressure when the operated part is subjected to the first brake operation or the second brake operation. The swivel drive device according to claim 1, wherein: The hydraulic pump is a variable displacement hydraulic pump,
The operated portion is subjected to the first brake operation or the second brake operation as compared with the capacity of the hydraulic pump when the swing body is operated to turn in the first direction or the second direction. The swing drive device according to any one of claims 1 to 3, further comprising a pump control unit that reduces a capacity of the hydraulic pump in a case where the pressure is reduced.   5. The swing drive device according to claim 4, wherein the brake control unit sets the target pressure so as to compensate for a decrease in brake force applied to the swing motor due to a decrease in the capacity of the hydraulic pump.   The brake control unit receives a first brake release operation from the second operation region to the neutral operation region after the first operation of the first brake, or the operated unit receives the second brake operation. When the second brake release operation from the first operation area to the neutral operation area is received later, the pump increases the capacity of the hydraulic pump that is reduced when the first brake operation or the second brake operation is received. A predetermined time elapses from the start of the pump capacity return operation by starting the capacity return operation and adjusting the flow rate of the hydraulic oil passing through the opening to generate the pressure loss of the hydraulic oil generated in the brake valve. 6. The turning drive device according to claim 4 or 5, wherein a brake releasing operation that disappears later is executed. The aircraft,
A revolving structure disposed above the airframe;
The turning drive device according to any one of claims 1 to 6,
A work machine comprising:

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