JP2019219017A - Hydraulic motor unit - Google Patents

Abstract

To prevent a hydraulic motor unit from being made large.SOLUTION: A hydraulic motor unit 100 comprises: a counter balance valve 40 for allowing an operation of a piston motor 1 and holding a stop state of the piston motor 1; a capacity switch valve 50 for controlling a flow of a hydraulic oil supplied to switch actuators 20, 21; and a high pressure election valve 60 for returning the hydraulic liquid exhausted from the piston motor 1 to a supply side during deceleration of the piston motor 1. The capacity switch valve 50, the couter balance valve 40, and the high pressure selection valve 60 respectively have spools provided in parallel to a second direction vertical to a first direction parallel to a rotation shaft 1a of the piston motor 1. The counter balance valve 40 and the capacity switch valve 50 are sequentially provided in a third direction vertical to the first and second directions.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hydraulic motor unit including a hydraulic piston motor whose displacement varies according to the tilt angle of a swash plate.

  Patent Document 1 discloses a hydraulic drive device applied to drive a hydraulic motor used as a traveling device of a construction machine, wherein a counter balance valve provided in a main circuit connecting a hydraulic source and a hydraulic motor; A high pressure selector valve provided in a return circuit branched from the upstream of the balance valve to prevent cavitation is disclosed.

JP-A-2002-39109

  In the hydraulic motor unit, the flow of hydraulic fluid supplied to and discharged from the hydraulic piston motor is controlled by a plurality of valves. For this reason, a plurality of flow paths are complicatedly formed in the valve housing that houses the valve.

  The flow path formed in the valve housing desirably has a low flow path resistance in order to secure a flow rate of the working fluid passing therethrough. However, since a plurality of flow paths are configured in a complicated manner, it is difficult to reduce the flow path resistance by increasing the cross-sectional area of the flow path within a limited space. When the cross-sectional area of the flow path is increased, the size of the valve housing may be increased.

  The present invention has been made in view of such a technical problem, and an object of the present invention is to provide a hydraulic motor unit in which a valve housing is downsized while securing a flow rate of a passage formed in a valve housing. And

  A first invention is a hydraulic motor unit, which controls a flow of hydraulic fluid supplied to and discharged from the hydraulic piston motor, wherein the displacement of the hydraulic piston motor changes according to the tilt angle of the swash plate. A hydraulic motor control device, wherein the hydraulic piston motor has a switching actuator for driving a swash plate to change the volume, and the hydraulic motor control device has an external supply of hydraulic fluid supplied from a hydraulic pressure source. Hydraulic fluid from ports and external ports is guided to allow operation of the hydraulic piston motor and to control the balance of the hydraulic piston motor, and to control the flow of hydraulic fluid supplied to the switching actuator A volume switching valve, a high-pressure selection valve for returning hydraulic fluid discharged from the hydraulic piston motor to the supply side when the hydraulic piston motor decelerates, and an external port formed and A single valve housing that houses a displacement valve, a counterbalance valve, and a high pressure selector valve, and is attached to the hydraulic piston motor, the volume switching valve, the counterbalance valve, and the high pressure selector valve comprise a hydraulic piston motor. Each of which has a spool provided in parallel with a second direction perpendicular to a first direction parallel to the rotation axis of the counter valve, wherein a high-pressure selection valve is provided between the counterbalance valve and the volume switching valve when viewed from the first direction. It is characterized by being provided in.

  In the first invention, the upstream-side counterbalance valve through which the hydraulic fluid from the hydraulic pressure source is guided through the external port, and the downstream-side volume switching valve through which the hydraulic fluid is guided to the switching actuator of the hydraulic piston motor. A high pressure selector valve is provided. Therefore, the external port and the counterbalance valve can be arranged closer to each other on one side in the third direction, and the switching actuator and the volume switching valve can be arranged closer to each other on the other side in the third direction. Therefore, the flow path connecting the counter balance valve and the external port can be configured to be short, and the flow path resistance is reduced. Further, the flow path connecting the volume switching valve and the switching actuator can be configured to be short, and the flow path resistance is reduced. Further, by arranging the high pressure selection valve between the counter balance valve and the volume switching valve, the space in the valve housing can be used efficiently.

  The second invention is further provided with a communication passage communicating the counterbalance valve and the high-pressure selection valve, and the communication passage has a flat shape having a cross section extending in the first direction.

  In the second aspect, the communication passage has a flat cross-sectional shape extending in the first direction in which a dead space is more likely to occur than in the second direction. For this reason, compared with the case where the cross-sectional shape is not flat, the flow path cross-sectional area of the communication path can be increased by using the dead space in the first direction. Therefore, the flow rate of the hydraulic oil returned to the supply side by the high-pressure selection valve increases, and the occurrence of cavitation can be suppressed more reliably.

  A third aspect of the invention is characterized in that at least one spool of the counterbalance valve, the high-pressure selection valve, and the volume switching valve is arranged so that the position in the first direction is shifted from the other spools.

  According to a fourth aspect of the present invention, the counterbalance valve has a check valve that allows a flow of the hydraulic fluid supplied to the hydraulic piston motor and blocks a flow of the hydraulic fluid discharged from the hydraulic piston motor. Is provided between the counterbalance valve and the high-pressure selection valve when viewed from the first direction, and is provided to be offset from the spool of the counterbalance valve toward one side in the first direction. It is characterized in that it is provided offset from the check valve toward the other side in the first direction, and the volume switching valve is offset from the high-pressure selection valve toward one side in the first direction.

  In the third and fourth inventions, the distance between the spools can be shortened by displacing the spools in the first direction, so that the valve housing can be downsized.

  The fifth invention is characterized in that the respective spools of the counterbalance valve, the high-pressure selection valve, and the volume switching valve are arranged in the third direction.

  According to the fifth aspect, since the accommodation holes for accommodating the respective spools can be formed by casting using one mold, the manufacturing cost can be reduced.

  ADVANTAGE OF THE INVENTION According to this invention, a valve housing can be miniaturized, ensuring the flow volume of the flow path formed in a valve housing.

FIG. 3 is a hydraulic circuit diagram of the hydraulic motor unit according to the embodiment of the present invention. It is sectional drawing of the hydraulic motor unit which concerns on embodiment of this invention, Comprising: It is sectional drawing along the II-II line in FIG. It is a sectional view showing a hydraulic motor control device in a hydraulic motor unit concerning an embodiment of the present invention. FIG. 4 is a cross-sectional view illustrating a communication passage in the hydraulic motor unit according to the embodiment of the present invention, and is a cross-sectional view taken along a line IV-IV in FIG. 2. It is sectional drawing of the 1st modification of the hydraulic motor unit which concerns on embodiment of this invention. It is sectional drawing which shows the hydraulic motor control apparatus of the 2nd modification of the hydraulic motor unit which concerns on embodiment of this invention. It is a hydraulic circuit diagram of the 3rd modification of the hydraulic motor unit concerning an embodiment of the present invention. It is sectional drawing which shows the hydraulic motor control apparatus of the 3rd modification of the hydraulic motor unit which concerns on embodiment of this invention.

  Hereinafter, a hydraulic motor unit 100 according to an embodiment of the present invention will be described with reference to the accompanying drawings.

  The hydraulic motor unit 100 is mounted on a working machine such as a hydraulic shovel and controls a traveling device of the working machine (not shown).

  FIG. 1 is a hydraulic circuit diagram of the hydraulic motor unit 100. First, the overall configuration and operation of the hydraulic motor unit 100 will be described with reference to FIG.

  The hydraulic motor unit 100 includes a hydraulic piston motor (hereinafter, simply referred to as a “piston motor”) 1 whose displacement is changed according to the tilt angle of the swash plate 7, and a liquid that controls the operation of the piston motor 1. It includes a pressure motor control device 30 and a brake device 25 that brakes the rotating body 3a that rotates together with the piston motor 1.

  The piston motor 1 is a swash plate type hydraulic piston motor in which a rotating shaft 1a is rotated in a forward or reverse direction by hydraulic oil (hydraulic fluid) selectively supplied to motor ports M1 and M2.

  The piston motor 1 has a pair of switching actuators 20 and 21 for switching the tilt angle of the swash plate 7 and a swash plate spring 11 for urging the swash plate 7.

  The capacity of the piston motor 1 becomes maximum when the tilt angle of the swash plate 7 becomes maximum, and becomes minimum when the tilt angle of the swash plate 7 becomes minimum. The swash plate spring 11 biases the swash plate 7 in a direction to increase the tilt angle of the swash plate 7. The switching actuators 20 and 21 extend in a direction to reduce the tilt angle of the swash plate 7. That is, the tilt angle of the swash plate 7 changes according to the urging force of the swash plate spring 11 and the thrust of the switching actuators 20 and 21. The rotation of the rotating shaft 1a of the piston motor 1 is transmitted to drive wheels of a working machine as a drive target via a speed reducer (not shown).

  The brake device 25 includes a brake 27 that generates a friction braking force by abutting on the rotating body 3 a, a brake spring 26 that presses the brake 27 against the rotating body 3 a, and a pressure chamber into which operating hydraulic pressure is guided through a brake release passage 29. 28. When the operating oil pressure is guided to the pressure chamber 28, a thrust separating from the rotating body 3 a is exerted on the brake 27. When the operating oil pressure guided to the pressure chamber 28 through the brake release passage 29 is low, the brake device 25 is extended by the urging force of the brake spring 26. Accordingly, the brake 27 is pressed against the rotating body 3a, and the rotating body 3a is braked. On the other hand, when the operating oil pressure guided to the pressure chamber 28 is increased, the brake element 27 contracts and operates against the urging force of the brake spring 26. As a result, the braking element 27 is retracted and separated from the rotating body 3a, and the braking of the rotating body 3a is released. Thus, the brake device 25 is a negative type brake. A throttle 25a is provided in the brake release passage 29. The pressure fluctuation in the pressure chamber 28 is reduced by the throttle 25a.

  The hydraulic motor control device 30 controls the piston motor 1 by allowing the operation of the piston motor 1 and maintaining the stopped state of the piston motor 1, and by changing the displacement of the swash plate 7 to change the displacement. A switching valve 50 for switching the operation speed of the piston motor 1, a high-pressure selection valve 60 for returning the hydraulic oil discharged from the piston motor 1 to the supply side when the piston motor 1 is decelerated, and a second valve connected to the piston motor 1 and circulating the hydraulic oil. A first main passage 32 and a second main passage 33; Here, the displacement volume is a geometric volume that the piston motor 1 displaces per rotation.

  The hydraulic motor control device 30 has a plurality of ports P1, P2, T, and Ps that communicate with the outside. A pump 70 as a hydraulic pressure source for pressurizing and supplying hydraulic oil is connected to the supply / discharge ports P1 and P2 as external ports. A tank 71 for storing hydraulic oil is connected to the tank port T. A pilot pressure supply source (not shown) is connected to the pilot supply / discharge port Ps. The supply / discharge port P1 is connected to the motor port M1 of the piston motor 1 via the first main passage 32. The supply / discharge port P2 is connected to the motor port M2 of the piston motor 1 via the second main passage 33.

  Between the hydraulic motor control device 30 and the pump 70, a travel control valve 72 for switching which of the supply / discharge ports P1 and P2 hydraulic oil supplied from the pump 70 is guided is interposed. The travel control valve 72 has a forward rotation position 72A for rotating the piston motor 1 forward, a stop position 72B for stopping the piston motor 1, and a reverse rotation position 72C for rotating the piston motor 1 in the reverse direction. The position of the travel control valve 72 is switched by operating the operation lever 73 by the operator. By this operation, the working machine moves forward, backward or stops.

  Hydraulic oil discharged from the pump 70 is guided to the supply / discharge ports P1 and P2 through the discharge passage 75. A relief passage 76 communicating with a discharge passage 74 communicating with the tank 71 is connected to a discharge passage 75 between the pump 70 and the travel control valve 72. In the relief passage 76, a relief valve 77 that opens when the pressure of the hydraulic oil guided from the pump 70 to the travel control valve 72 reaches a predetermined relief pressure and guides the hydraulic oil discharged from the pump 70 to the tank 71 is provided. Provided.

  The counter balance valve 40 is a spool valve interposed in the first main passage 32 and the second main passage 33. As shown in FIG. 1, the counter balance valve 40 includes two valve ports 42a and 42b communicating with the supply / discharge ports P1 and P2, and two valve ports 42c and 42d communicating with the motor ports M1 and M2. It has a valve port 42e that communicates with the pressure chamber 28 of the brake device 25 through the brake release passage 29, and a valve port 42f that communicates with the tank port T through the drain passage 36.

  The counter balance valve 40 includes a pilot chamber 44a into which hydraulic oil supplied from the pump 70 is guided through a pilot passage 45a provided with a throttle 46a, and a hydraulic oil supplied from the pump 70 through a pilot passage 45b provided with a throttle 46b. , And two return springs 43a and 43b for urging the first spool 41 described later.

  The counter balance valve 40 has a first operating position 40A, a second operating position 40B, and a stop position 40C.

  The thrust by the pressure of the hydraulic oil guided to the pilot chamber 44a acts so that the counterbalance valve 40 is located at the first operating position 40A. When the counterbalance valve 40 is located at the first operating position 40A, the valve port 42a and the valve port 42e communicate with each other. In the first operation position 40A, the valve port 42b and the valve port 42d communicate with each other. In the first operating position 40A, the valve port 42c and the valve port 42f are shut off.

  The thrust by the pressure of the hydraulic oil guided to the pilot chamber 44b acts so that the counterbalance valve 40 is located at the second operating position 40B. When the counterbalance valve 40 is located at the second operation position 40B, the valve port 42b and the valve port 42e communicate with each other. In the second operation position 40B, the valve port 42a and the valve port 42c communicate with each other. In the second operation position 40B, the valve port 42d and the valve port 42f are shut off.

  The biasing forces of the return springs 43a and 43b act so that the counterbalance valve 40 is located at the stop position 40C. When the counterbalance valve 40 is located at the stop position 40C, the valve port 42f and the valve port 42e communicate. At the stop position 40C, the valve port 42a, the valve port 42b, the valve port 42c, and the valve port 42d are shut off.

  The counter balance valve 40 includes a check valve 47 provided in a first bypass passage 32 a branched from the upstream of the counter balance valve 40 and connected to the downstream in the first main passage 32, and a counter balance in the second main passage 33. A check valve 48 is provided in a second bypass passage 33a branched from the upstream of the valve 40 and connected downstream. The upstream of the counter balance valve 40 in the first main passage 32 and the second main passage 33 connects the counter balance valve 40 and the supply / discharge ports P1 and P2 in the first main passage 32 and the second main passage 33. Part. The downstream of the counter balance valve 40 in the first main passage 32 and the second main passage 33 is a portion connecting the counter balance valve 40 and the motor ports M1 and M2 in the first main passage 32 and the second main passage 33. It is.

  The check valve 47 allows the flow of hydraulic oil supplied to the piston motor 1 from the supply / discharge port P1 through the first bypass passage 32a, and shuts off the flow of hydraulic oil discharged from the piston motor 1. The check valve 48 allows the flow of hydraulic oil supplied from the pump port P2 to the piston motor 1 through the second bypass passage 33a, and shuts off the flow of hydraulic oil discharged from the piston motor 1. The check valves 47 and 48 prevent the hydraulic oil from flowing backward from the piston motor 1 to the pump 70 due to a load acting on the opposite side of the rotation direction of the piston motor 1 (for example, a self-weight acting during uphill traveling). .

  The volume switching valve 50 is a spool valve that switches between supply and discharge of hydraulic oil to the switching actuators 20 and 21.

  The volume switching valve 50 communicates with the first supply port 52a communicating with the first main passage 32 on the motor port M1 side through the first branch passage 34, and with the second main passage 33 on the motor port M2 side through the second branch passage 35. A second supply port 52b, a drain port 52c communicating with the tank port T through the drain passage 36, a first control port 52d communicating with the switching actuator 20 through the first switching passage 22 provided with the throttle 22a, and a throttle 23a. A second control port 52e that communicates with the switching actuator 21 through the second switching passage 23 provided.

  The volume switching valve 50 further includes a pilot chamber 54 into which pilot pressure is guided from a pilot supply / discharge port Ps, and a spring 55 that urges a second spool 51 described below against the pilot pressure.

  The pilot pressure supplied from the pilot supply / discharge port Ps to the pilot chamber 54 is determined by the pilot pressure when a speed switching lever (not shown) for switching the traveling speed of the working machine between low speed and high speed is operated by the operator to the high speed side. It is supplied from the supply source and is not supplied when the operation lever is on the low speed side.

  The volume switching valve 50 has a low speed position 50A and a high speed position 50B.

  The urging force of the spring 55 acts so that the volume switching valve 50 is located at the low speed position 50A. At the low speed position 50A, both the first control port 52d and the second control port 52e communicate with the drain port 52c. In the low speed position 30A, the first supply port 52a and the second supply port 52b are shut off.

  On the other hand, the thrust by the pilot pressure guided to the pilot chamber 54 acts so that the volume switching valve 50 is located at the high-speed position 50B. At the high-speed position 50B, the first control port 52d communicates with the first supply port 52a, and the second control port 52e communicates with the second supply port 52b. In the high-speed position 50B, the communication of the drain port 52c is interrupted to both the first control port 52d and the second control port 52e.

  The high-pressure selection valve 60 is a spool valve for preventing cavitation when the piston motor 1 stops after deceleration, and functions as a so-called anti-cavitation valve.

  The high-pressure selection valve 60 communicates with the first upstream port 62a communicating with the supply / discharge port P1 through the third branch passage 37 and the first main passage 32, and with the supply / discharge port P2 through the fourth branch passage 38 and the second main passage 33. A second upstream port 62b, and a downstream port 62c communicating with the valve port 42e of the counterbalance valve 40 through the return passage 39 and the brake release passage 29. The third branch passage 37 branches from the first main passage 32 upstream of the counter balance valve 40. The fourth branch passage 38 branches from the second main passage 33 upstream of the counter balance valve 40.

  The high-pressure selection valve 60 communicates the third branch passage 37 with the return passage 39 and communicates the first return position 60A that blocks the fourth branch passage 38 with the fourth branch passage 38 and the return passage 39. It has a second return position 60B for blocking the three-branch passage 37, and a blocking position 60C for blocking communication between the third branch passage 37, the fourth branch passage 38, and the return passage 39, respectively.

  The high-pressure selection valve 60 urges pilot chambers 64a and 64b in which the pressures of the third branch passage 37 and the fourth branch passage 38 are guided as pilot pressures through the pilot passages 65a and 65b, respectively, and a third spool 61 described later. And two return springs 63a and 63b.

  The high-pressure selection valve 60 has a first return position 60A, a second return position 60B, and a shutoff position 60C.

  The pressure in one pilot chamber 64a acts on the third spool 61 so that the high-pressure selection valve 60 is at the first return position 60A. At the first return position 60A, the first upstream port 62a communicates with the downstream port 62c, and the second upstream port 62b is shut off.

  The pressure in the other pilot chamber 64b acts on the third spool 61 so that the high-pressure selection valve 60 is at the second return position 60B. At the second return position 60B, the second upstream port 62b communicates with the downstream port 62c, and the first upstream port 62a is shut off.

  The pair of return springs 63a and 63b support the third spool 61 so that the high-pressure selection valve 60 is located at the shut-off position 60C. At the cutoff position 60C, the downstream port 62c is cut off from both the first upstream port 62a and the second upstream port 62b.

  Next, the operation of the counterbalance valve 40 will be described.

  When the operation lever 73 of the travel control valve 72 is operated by the operator and the travel control valve 72 switches from the stop position 72B to the forward rotation position 72A, the supply / discharge port P1 is connected to the pump 70, and the supply / discharge port P2 is connected to the discharge passage. It is connected to the tank 71 through 74.

  When the hydraulic oil is supplied from the pump 70 to the supply / discharge port P1, a part of the hydraulic oil is supplied to the motor port M1 of the piston motor 1 through the first main passage 32 and the first bypass passage 32a. A part of the hydraulic oil is guided from the first main passage 32 to the pilot chamber 44a of the counterbalance valve 40 through the pilot passage 45a. The position of the counterbalance valve 40 is switched to the first operating position 40A by the thrust by the pressure of the operating oil guided to the pilot chamber 44a. At the first operating position 40A, the operating oil flowing out of the motor port M2 is returned to the tank 71 through the second main passage 33, the supply / discharge port P2, and the discharge passage 74. Further, hydraulic oil is supplied from the first main passage 32 to the pressure chamber 28 of the brake device 25 through the brake release passage 29. As a result, the brake device 25 is maintained in a state where the braking is released, and the piston motor 1 rotates in the forward direction.

  On the other hand, when the operation lever 73 of the travel control valve 72 is operated by the operator and the travel control valve 72 switches from the stop position 72B to the reverse rotation position 72C, the supply / discharge port P2 is connected to the pump 70, and the supply / discharge port P1 is It is connected to the tank 71 through the discharge passage 74.

  When the hydraulic oil is supplied from the pump 70 to the supply / discharge port P2, a part of the hydraulic oil is supplied to the motor port M2 of the piston motor 1 through the second main passage 33 and the second bypass passage 33a. Further, a part of the hydraulic oil is guided from the second main passage 33 to the pilot chamber 44b of the counter balance valve 40 through the pilot passage 45b. The position of the counterbalance valve 40 is switched to the second operating position 40B by the thrust by the pressure of the operating oil guided to the pilot chamber 44b. At the second operation position 40B, the operating oil flowing out of the motor port M1 is returned to the tank 71 through the first main passage 32, the supply / discharge port P1, and the discharge passage 74. Further, hydraulic oil is supplied from the second main passage 33 to the pressure chamber 28 of the brake device 25 through the brake release passage 29. As a result, the brake device 25 is maintained in a state where the braking is released, and the piston motor 1 rotates in the reverse direction.

  When the operation lever 53 of the travel control valve 72 is operated by the operator and the travel control valve 72 is switched to the stop position 52B, the two supply / discharge ports P1 and P2 communicate with the tank 71 through the discharge passage 74 and discharge from the pump 70. The operating oil is returned to the tank 71 through the discharge passage 74 via the relief valve 77. Since the pressure difference between the two supply and discharge ports P1 and P2 disappears, and the thrust by the pressure of the hydraulic oil in the pilot chamber 44a and the thrust by the pressure of the hydraulic oil in the pilot chamber 44b become the same, the position of the counter balance valve 40 becomes The position is switched to the stop position 40C by the urging force of the return springs 43a and 43b. At the stop position 40C, the flow of hydraulic oil from the motor ports M1 and M2 to the supply / discharge ports P1 and P2 is cut off, and the flow of hydraulic oil to the pressure chamber 28 of the brake device 25 is also cut off. Accordingly, the brake device 25 is extended by the urging force of the brake spring 26, and brakes the rotating body 3a. Therefore, the piston motor 1 stops rotating and continues to stop. As described above, the counterbalance valve 40 allows the operation of the piston motor 1 and maintains the stopped state of the piston motor 1 according to the pressure of the operating oil supplied to the supply / discharge ports P1 and P2.

  When the position of the counterbalance valve 40 switches rapidly, the state of the piston motor 1 rapidly changes from a stopped state to a rotating state or from a rotating state to a stopped state. Such a change may generate vibrations when the working machine starts traveling and when traveling stops, which may give an impact to the operator. In the present embodiment, the flow of hydraulic oil guided to the pilot chambers 44a and 44b through the pilot passages 45a and 45b and the hydraulic oil discharged from the pilot chambers 44a and 44b by the throttles 46a and 46b provided in the pilot passages 45a and 45b. Resistance is applied to the flow of For this reason, the position of the counterbalance valve 40 is prevented from being rapidly switched, and the impact when the state of the piston motor 1 changes is reduced.

  Next, the operation of the volume switching valve 50 will be described.

  When the work implement is traveling and the speed switching lever (not shown) is not operated to the high speed side by the operator, the pilot pressure is not guided to the pilot chamber 54 of the volume switching valve 50. Therefore, the position of the volume switching valve 50 is maintained at the low speed position 50A by the urging force of the spring 55. At this time, each of the switching actuators 20 and 21 communicates with the tank port T through the first switching passage 22 or the second switching passage 23, respectively. Therefore, the switching actuators 20 and 21 contract due to the urging force of the swash plate spring 11. When the tilting angle of the swash plate 7 becomes maximum due to the urging force of the swash plate spring 11, the capacity of the piston motor 1 becomes maximum, and the piston motor 1 operates at a low speed. As a result, the traveling speed of the working machine becomes low.

  On the other hand, when the speed switching lever is operated to the high speed side by the operator, pilot pressure is guided to the pilot chamber 54. When the thrust by the pilot pressure guided to the pilot chamber 54 exceeds the urging force by the spring 55, the volume switching valve 50 switches to the high-speed position 30B. At this time, the switching actuator 20 communicates with the first main passage 32 through the first switching passage 22 and the first branch passage 34, and the switching actuator 21 communicates with the second main passage 33 through the second switching passage 23 and the second branch passage 35. Communicate. During traveling of the work machine, hydraulic oil discharged from the pump 70 is guided to one of the first main passage 32 and the second main passage 33. For this reason, in one of the switching actuators 20 and 21, the operating oil discharged from the pump 70 is guided through the first main passage 32 or the second main passage 33, and expands against the urging force of the swash plate spring 11. I do. When the tilt angle of the swash plate 7 becomes minimum due to the thrust of the switching actuators 20 and 21, the capacity of the piston motor 1 becomes minimum, and the piston motor 1 operates at high speed. As a result, the traveling speed of the working machine becomes high.

  When the position of the volume switching valve 50 switches rapidly, the tilt angle of the swash plate 7 changes rapidly, and the operating speed of the piston motor 1 changes rapidly. Such a change also affects a change in the traveling speed of the work machine, and may give an impact to the operator due to a sudden change in the traveling speed. In the present embodiment, resistance is given to the flow of hydraulic oil flowing into and out of the switching actuators 20, 21 by the throttles 22a, 23a provided in the first switching passage 22 and the second switching passage 23, respectively. For this reason, the contraction and extension operations of the switching actuators 20 and 21 become slow, and the impact caused by the shift of the piston motor 1 is reduced.

  Next, the operation of the high-pressure selection valve 60 will be described.

  When the travel control valve 72 is in the forward rotation position 72A, a part of the hydraulic oil discharged from the pump 70 is guided to the pilot chamber 64a of the high-pressure selection valve 60 through the third branch passage 37 and the pilot passage 65a. Therefore, the high pressure selection valve 60 is located at the first return position 60A, and the third branch passage 37 communicates with the valve port 42e of the counter balance valve 40 through the return passage 39.

  When the travel control valve 72 switches from the forward rotation position 72A to the stop position 72B based on the operation of the operation lever 73 by the operator, the supply of the hydraulic oil from the pump 70 through the supply / discharge ports P1 and P2 is shut off. Accordingly, as described above, the supply of the hydraulic oil to the piston motor 1 is stopped, and the rotating body 3a is braked by the brake device 25.

  When the piston motor 1 decelerates to the stop state in this manner, even if the supply of the hydraulic oil to the piston motor 1 is stopped, the rotating body 3a does not stop immediately but slightly rotates due to inertia. Therefore, with the rotation of the rotating body 3a due to inertia, the piston motor 1 sucks the operating oil from the first main passage 32 even when the supply of the operating oil from the pump 70 is shut off, and the second main passage The hydraulic oil is discharged to 33 and slightly rotated. When the piston motor 1 rotates while the supply of the hydraulic oil is shut off, the pressure in the first main passage 32 on the suction side is reduced, and the pressure in the second main passage 33 is relatively increased.

  Here, since the throttle passages 46a and 46b are provided in the pilot passages 45a and 45b of the counter balance valve 40, rapid pressure changes in the pilot chambers 44a and 44b are suppressed. Therefore, even if the travel control valve 72 is switched to the stop position 72B and the pressure in the first main passage 32 is relatively low and the pressure in the second main passage 33 is relatively high, the counter balance valve 40 operates in the first operation mode. It is located at position 40A. Therefore, in this state, the valve port 42a communicates with the valve port 42e, and the valve port 42b communicates with the valve port 42d.

  On the other hand, no throttle is provided in the pilot passages 65a and 65b of the high-pressure selection valve 60. Therefore, when the pressure in the first main passage 32 is relatively low and the pressure in the second main passage 33 is relatively high, the high-pressure selection valve 60 moves to the second return position 60B according to the pressure difference between the pilot chambers 64a and 64b. Switch. As described above, when the piston motor 1 rotates in the normal rotation direction due to inertia, the high-pressure selection valve 60 is at the second return position 60B, and the fourth branch passage 38 communicates with the valve port 42e of the counterbalance valve 40. .

  Therefore, when the piston motor 1 rotates in the normal rotation direction due to inertia when stopped, the hydraulic oil discharged from the piston motor 1 returns from the second main passage 33 through the valve ports 42 d and 42 b of the counter balance valve 40. 39 and the high pressure selection valve 60. The hydraulic oil guided to the high-pressure selection valve 60 in this manner is guided to the valve port 42e of the counterbalance valve 40. The hydraulic oil guided to the valve port 42e is guided to the first bypass passage 32a through the valve port 42a, opens the check valve 47, and is returned to the first main passage 32. In this way, the hydraulic oil discharged from the piston motor 1 through the second main passage 33 is returned to the first main passage 32 on the suction side where the pressure is relatively low. For this reason, it is possible to suppress the occurrence of cavitation by reducing the pressure in the first main passage 32 on the suction side to a negative pressure when stopped.

  Conversely, when the piston motor 1 is decelerated from the state of rotation in the reverse rotation direction and stops, the first main passage 32 has a relatively high pressure and the second main passage 33 has a relatively low pressure. Therefore, the high-pressure selection valve 60 is located at the first return position 60A while the counter balance valve 40 maintains the second operation position 40B. For this reason, the hydraulic oil discharged from the piston motor 1 rotated by inertia to the first main passage 32 is guided to the valve port 42 e of the counter balance valve 40 through the high pressure selection valve 60 and the return passage 39. The hydraulic oil guided to the valve port 42e is guided to the second bypass passage 33a, opens the check valve 48, and is returned to the second main passage 33 at a relatively low pressure. For this reason, it is possible to suppress the occurrence of cavitation by reducing the pressure of the second main passage 33 on the suction side to a negative pressure when stopped.

  As described above, when the piston motor 1 is decelerated and stopped, the high-pressure selection valve 60 operates so as to return the hydraulic oil to the suction side, and causes the first main passage 32 and the first main passage 32 generated due to rotation due to inertia. Cavitation in the second main passage 33 is suppressed.

  Next, a specific structure of the hydraulic motor unit 100 will be described with reference to FIGS.

  First, a specific structure of the piston motor 1 will be described.

  As shown in FIG. 2, the piston motor 1 includes a motor housing 2, a rotating shaft 1a having one end rotatably supported by the motor housing 2, and a cylinder block connected to the rotating shaft 1a and integrally rotating with the rotating shaft 1a. 3 is provided.

  The motor housing 2 has a housing recess 2 a for housing the cylinder block 3. A valve housing 31 described later is attached to the motor housing 2, and the opening of the housing recess 2 a is closed by the valve housing 31. That is, the valve housing 31 also functions as a cover for the opening of the housing recess 2a.

  The rotating shaft 1a is connected to a speed reducer (not shown), and the rotation of the rotating shaft 1a is reduced by the speed reducer and transmitted to the driven object. One end of the rotating shaft 1a is rotatably supported by the motor housing 2, and the other end is rotatably supported by the valve housing 31.

  A plurality of cylinders 4 are opened on a concentric circle centered on the rotation axis 1a in the cylinder block 3 in parallel with the rotation axis 1a. A piston 6 defining a volume chamber 5 is reciprocally slidably inserted into each cylinder 4.

  A shoe 9 is connected to a tip of the piston 6 via a spherical seat 10. The shoe 9 is in surface contact with the swash plate 7 provided to be angularly displaceable with respect to the motor housing 2. As the cylinder block 3 rotates, each shoe 9 comes into sliding contact with the swash plate 7, and each piston 6 reciprocates with a stroke amount corresponding to the tilt angle of the swash plate 7.

  Between the cylinder block 3 and the valve housing 31, a valve plate 8 with which the base end surface of the cylinder block 3 slides is attached. Motor ports M1 and M2 (see FIG. 1) are formed in the valve plate 8 in an arc shape. Each piston 6 protrudes from the cylinder 4 by hydraulic pressure guided from the pump 70 to each volume chamber 5 via the motor ports M1 and M2, and each piston 6 pushes the swash plate 7 via the shoe 9 to rotate the cylinder block 3. I do. Therefore, the rotation shaft 1a rotates.

  The switching actuators 20 and 21 are provided inside the wall of the motor housing 2 so as to face the end surface of the swash plate 7 opposite to the sliding surface 7a with which the shoe 9 slides. The switching actuators 20, 21 include cylinders 20a, 21a formed in the motor housing 2, and switching pistons 20b, 21b slidably provided in the cylinders 20a, 21a and abutting on the end surfaces of the swash plate 7. The swash plate 7 is tilted with respect to the rotation shaft 1a when the switching actuators 20 and 21 advance and retreat. In FIG. 2, only a single switching actuator 20 is shown, and the configuration of the other switching actuator 21 is indicated by reference numerals in parentheses.

  A friction braking type brake device 25 for braking the rotation of the cylinder block 3 is built in the housing recess 2 a of the motor housing 2.

  The brake device 25 is provided between the brake element 27 and the valve housing 31 by generating a friction braking force between the brake element 27 and the rotary element 3 a by contacting the rotary element 3 a that rotates together with the cylinder block 3. And a pressure chamber 28 defined between the brake element 27 and the motor housing 2. The brake 27 is provided in the motor housing 2 so as not to rotate, and is configured to be movable in the direction of the rotation shaft 1 a in the motor housing 2. Since the operation of the brake device 25 is as described above, a detailed description is omitted.

  Next, a specific structure of the hydraulic motor control device 30 will be described. In the following, for convenience of description, as shown in FIGS. 2 and 3, a direction parallel to the rotation axis 1 a of the piston motor 1 is referred to as a “first direction”, and two directions perpendicular to the first direction are referred to as “first directions”. Description will be made as “two directions” and “third direction”. In FIG. 2, the first direction corresponds to the left-right direction, the second direction corresponds to the direction perpendicular to the page, and the third direction corresponds to the up-down direction. The first direction, the second direction, and the third direction are directions along three orthogonal axes orthogonal to each other. Further, both sides in the first direction are “front side” (one side in the first direction) and “rear side” (other side in the first direction), and both sides in the third direction are “upper side” (one side in the third direction). Side) and "lower side" (the other side in the third direction).

  As shown in FIG. 2, the hydraulic motor control device 30 includes a single valve housing 31 that houses the counterbalance valve 40, the volume switching valve 50, and the high-pressure selection valve 60. That is, the counter balance valve 40, the volume switching valve 50, and the high-pressure selection valve 60 have a common housing. When the valve housing 31 is composed of a plurality of housing members, in order to mainly prevent oil leakage, a finishing portion is applied to a contact portion between the housing members to provide a seal member between them, or after assembly, It is necessary to perform a process of checking whether or not oil leakage occurs from the contact portion. On the other hand, by using the single valve housing 31, the man-hour required for the seal member, the machining, the inspection of the oil leak, and the like can be reduced, and the cost can be reduced.

  As shown in FIG. 3, the spool 41 of the counter balance valve 40 (hereinafter, also referred to as “first spool 41”), the spool 51 of the volume switching valve 50 (hereinafter, also referred to as “second spool 51”), and high pressure. The spool 61 of the selection valve 60 (hereinafter, also referred to as “third spool 61”) is slidably inserted into first to third accommodation holes 41a, 51a, 61a formed in the valve housing 31, respectively. The check valves 47 and 48 of the counterbalance valve 40 are housed in valve housing holes 47a and 48a coaxially arranged along the second direction. In FIG. 2, the first to third spools 41, 51, 61 and the check valve 48 are shown in a schematic cross section.

  Supply / discharge ports P1 and P2, which are external ports, are formed in the valve housing 31 on the upper side in the third direction (upper side in FIG. 3).

  The spools 41, 51, 61 of the counter balance valve 40, the volume switching valve 50, and the high-pressure selection valve 60 are provided in parallel to the second direction as shown in FIG. As shown in FIGS. 2 and 3, the first spool 41 of the counterbalance valve 40 is provided relatively on the upper side in the third direction, and the second spool 51 of the volume switching valve 50 is relatively located on the lower side. And they are separated in the third direction. The third spool 61 of the high-pressure selection valve 60 is provided between the first spool 41 of the counterbalance valve 40 and the second spool 51 of the volume switching valve 50 when viewed from the first direction. That is, the third spool 61 of the high-pressure selection valve 60 is provided so that the position in the third direction is between the first spool 41 of the counterbalance valve 40 and the second spool 51 of the volume switching valve 50. Therefore, from the upper side to the lower side in the third direction, the first spool 41 of the counterbalance valve 40, the third spool 61 of the high-pressure selection valve 60, and the second spool 51 of the volume switching valve 50 are arranged in this order. . When viewed from the first direction, the check valves 47 and 48 of the counter balance valve 40 are positioned between the first spool 41 of the counter balance valve 40 and the third spool 61 of the high pressure selection valve 60 in the third direction. Placed in

  In the present specification, the expression “the third spool 61 is provided between the first spool 41 and the second spool 51” means that the center axis of the third spool 61 is the same as the center axis of the first spool 41. This means that it is located within a range defined by the center axis of the spool 51, and also includes that the position in the third direction matches the center axis of the first or second spool 51. However, desirably, the third spool 61 is displaced so as not to overlap with the first spool 41 and the second spool 51 when viewed from the first direction.

  As shown in FIG. 2, the check valves 47 and 48 of the counterbalance valve 40 are arranged to be shifted forward with respect to the first spool 41 of the counterbalance valve 40 in the first direction. The third spool 61 of the high-pressure selection valve 60 is arranged to be shifted rearward in the first direction with respect to the check valves 47 and 48 of the counterbalance valve 40. The second spool 51 of the volume switching valve 50 is arranged to be shifted forward in the first direction with respect to the third spool 61 of the high-pressure selection valve 60. Therefore, the first spool 61, the check valves 47 and 48 of the counterbalance valve 40, the third spool 61, and the second spool 51 are alternately arranged in a plane perpendicular to the second direction.

  By arranging the counterbalance valve 40, the volume switching valve 50, and the high-pressure selection valve 60 as described above, the supply / discharge ports P1, P2 and the counterbalance valve 40 can be arranged close to each other. Thereby, the length of the flow path (a part of the first main passage 32 and a part of the second main passage 33) between the supply / discharge ports P1, P2 and the counter balance valve 40 is shortened, and the flow path resistance is reduced. Can be smaller.

  Further, as shown in FIG. 2, the switching actuators 20, 21 are disposed below the rotation shaft 1a in the third direction. The volume switching valve 50 that controls the hydraulic oil supplied to the switching actuators 20 and 21 is also disposed relatively lower in the third direction. Therefore, the volume switching valve 50 and the switching actuators 20 and 21 can be arranged closer to each other on the lower side in the third direction. Therefore, the flow path length of the hydraulic oil guided from the volume switching valve 50 to the switching actuators 20 and 21 can be shortened, and the flow path resistance can be reduced.

  In this way, by arranging the supply / discharge ports P1 and P2 and the counter balance valve 40 close to each other, and by arranging the volume switching valve 50 and the switching actuators 20 and 21 close, the length of the flow path is shortened. Road resistance can be reduced. Therefore, the flow rate in the flow path in the valve housing 31 can be ensured without increasing the flow path cross-sectional area.

  Further, since the high-pressure selection valve 60 is disposed in the space between the counterbalance valve 40 and the volume switching valve 50, a limited space in the valve housing 31 can be effectively used, and the large size of the valve housing 31 Can be prevented.

  Here, it is desired that the passage formed in the valve housing 31, particularly the passage connecting the counterbalance valve 40 and the high-pressure selection valve 60, has a large passage flow rate in order to more reliably prevent cavitation. .

  In the hydraulic motor unit 100, as described above, the first to third spools 41, 51, 61 are provided so as to be parallel to the second direction and to be arranged in the third direction. For this reason, the flow path through which the hydraulic oil passes is provided side by side in the second direction so that the hydraulic oil flows mainly along the third direction. Therefore, in the hydraulic motor control device 30, since it is necessary to secure the strength of the wall between the flow paths arranged in the second direction, the cross-sectional area is increased in the second direction without increasing the size of the valve housing 31. It is difficult.

  Therefore, in the hydraulic motor unit 100, a passage (hereinafter, referred to as a “communication passage 66”) communicating the counterbalance valve 40 and the high-pressure selection valve 60 is formed in a flat shape extending in the first direction. . Specifically, the communication path 66 includes a part of the first main path 32, a part of the second main path 33, the third branch path 37, the fourth branch path 38, the first bypass path 32a, and the second bypass. A passage 33a and a return passage 39 are included. Hereinafter, a specific shape of the communication path 66 will be described with reference to FIG. FIG. 2 schematically shows the communication passage 66.

  As shown in FIG. 4, the cross-sectional shape of the communication passage 66 is formed in a substantially rectangular shape as a flat shape. In the cross-sectional shape of the communication passage 66, the long side 66b extends in a direction perpendicular to the second direction, and the short side 66a extends in parallel to the second direction. The long side 66b does not coincide with the first and third directions but is inclined with respect to both of them (see FIG. 2). The long side 66b of the cross section of the communication passage 66 is formed to extend in both the first direction and the third direction. In other words, the cross section of the communication passage 66 is formed such that the width in the direction perpendicular to the second direction is larger than the width along the second direction. As described above, the cross section of the communication passage 66 is formed in a flat shape extending in the first direction (and the third direction). The cross section of the communication path 66 is a cross section of the flow path orthogonal to the flow of the hydraulic oil passing through the communication path 66.

  As described above, since the communication passage 66 is formed to have a flat cross section extending in the first direction, it is possible to increase the cross-sectional area of the flow passage by using a relatively large dead space in the first direction. it can. Therefore, at the time of stoppage, the flow rate of the hydraulic oil guided from the relatively high pressure side to the low pressure side through the high pressure selection valve 60 can be secured among the first and second main passages 32 and 33. That is, by improving the flow path cross-sectional area of the communication passage 66, the suction performance (self-priming performance) during rotation due to the inertia of the piston motor 1 can be improved, and the occurrence of cavitation can be more reliably prevented. it can.

  Note that a flat cross section refers to a shape having a non-uniform width such as a perfect circle or a square, and includes not only a rectangle but also an ellipse and other polygons, and combinations thereof. The cross-sectional shape of the communication passage 66 is not limited to a substantially rectangular shape, and may be another flat shape. In order to increase the flow path cross-sectional area, it is particularly effective to make the cross-sectional shape extend in the first direction. If the flow rate can be secured, the communication path 66 does not need to be formed in a flat shape. Further, the passages constituting the communication passage 66 do not mean that the cross-sectional shapes are the same. Each passage constituting the communication passage 66 may be formed in a different cross-sectional shape.

  Further, since the high-pressure selection valve 60 is disposed between the counter balance valve 40 and the volume switching valve 50 in the third direction, it can be disposed close to the counter balance valve 40. For this reason, the length of the communication passages 66 and 67 for communicating the counterbalance valve 40 and the high-pressure selection valve 60 can be reduced, and the flow path resistance (pressure loss) can be reduced. Properties can be further improved.

  Next, a modified example of the present embodiment will be described.

  In the above embodiment, the first to third spools 41, 51, 61 and the check valves 47, 48 are alternately arranged in a plane perpendicular to the second direction. On the other hand, as shown in FIG. 5, the first to third spools 41, 51, 61 and the check valves 47, 48 may be provided so that the positions in the first direction are the same. In other words, the first to third spools 41, 51, 61 and the check valves 47, 48 may be provided on the same plane orthogonal to the first direction. When the first to third spools 41, 51, 61 and the check valves 47, 48 are arranged alternately, when manufacturing the valve housing 31 by casting, the first to third accommodation holes 41a, 51a, 61a. In addition, molds (so-called cores) for forming the valve housing holes 47a and 48a by casting must be formed alternately, which complicates the manufacture of the mold. On the other hand, the structure of the mold is simplified by arranging the first to third spools 41, 51, 61 and the check valves 47, 48 on the same plane orthogonal to the first direction. Can be. Therefore, the accommodation hole can be formed by one mold (so-called core), and the manufacturing cost can be reduced.

  Further, in the above embodiment, as shown in FIG. 3, the positions of the first spool 41, the check valves 47 and 48, and the third spool 61 in the third direction are arranged in this order from the upper side to the lower side. On the other hand, as shown in FIG. 6, the check valves 47 and 48, the first spool 41, and the third spool 61 may be arranged in this order from the upper side to the lower side in the third direction.

  In the above embodiment, the check valves 47 and 48 of the counter balance valve 40 are provided in the valve housing 31 independently of the first spool 41. On the other hand, the check valves 47 and 48 may be built in the first spool 41 of the counterbalance valve 40 as shown in FIGS. In this case, as shown in FIG. 7, in the first operation position 40A, the valve port 42a communicates with the valve port 42e and also communicates with the valve port 42c through the check valve 47, as shown in FIG. In the second operation position 40B, the valve port 42b communicates with the valve port 42e and also communicates with the valve port 42d through the check valve 48. In the stop position 40C, the valve port 42a communicates with the valve port 42c through the check valve 47, and the valve port 42b communicates with the valve port 42d through the check valve 48. Even in such a case, the same operation and effect as those of the above-described embodiment can be obtained.

  Further, for example, the hydraulic motor control device 30 according to the embodiment of the present invention is also applicable to control of a turning device for turning a cab of an excavator or a construction machine. Further, the present invention is not limited to construction machines, and may be applied to a rotary drive device provided in an agricultural machine or a ship. In these devices, when the operator operates the operation lever, the device rotates forward, reverse, or stops.

  Further, in the present embodiment, the working oil is used as the working fluid, but a working fluid such as a water-soluble substitute liquid may be used instead.

  According to the above embodiment, the following effects can be obtained.

  In the hydraulic motor unit 100, a high-pressure selection valve 60 is provided in the valve housing 31 between the upstream counterbalance valve 40 and the downstream volume switching valve 50 in the third direction. Therefore, in the third direction, the supply / discharge ports P1 and P2 and the counter balance valve 40 can be arranged closer to each other, and the switching actuators 20, 21 and the volume switching valve 50 can be arranged closer to each other. Thereby, the flow path length of the hydraulic oil is shortened, and the flow path resistance is reduced. By arranging the high-pressure selection valve 60 between the counterbalance valve 40 and the volume switching valve 50, the space in the valve housing 31 can be used efficiently. Therefore, while preventing the valve housing 31 from being enlarged, the resistance of the flow path through which the hydraulic oil flows can be reduced, and the flow rate can be ensured.

  In addition, since the communication passages 66 and 67 that communicate the counterbalance valve 40 and the high-pressure selection valve 60 have a width along the first direction larger than a width along the second direction, the communication passages 66 and 67 use a dead space to provide a flow path. The cross-sectional area can be increased. Therefore, the occurrence of cavitation can be suppressed more reliably.

  Hereinafter, the configuration, operation, and effect of the embodiment of the present invention will be described together.

  The hydraulic motor unit 100 includes a piston motor 1 whose displacement is changed according to the tilt angle of the swash plate 7, a hydraulic motor control device 30 that controls the flow of hydraulic oil supplied to and discharged from the piston motor 1, The piston motor 1 has switching actuators 20 and 21 for changing the volume by driving the swash plate 7, and the hydraulic motor control device 30 includes a supply / discharge port P 1 where hydraulic oil is supplied from a pump 70. P2 and hydraulic oil from the supply / discharge ports P1 and P2 are guided and supplied to the counterbalance valve 40 that allows the piston motor 1 to operate and keeps the piston motor 1 stopped, and the switching actuators 20 and 21. A volume switching valve 50 for controlling the flow of hydraulic oil, and a high-pressure selection valve for returning hydraulic fluid discharged from the piston motor 1 to the supply side when the piston motor 1 is decelerated 0, and a single valve housing 31 formed with the supply / discharge ports P1 and P2 and accommodating the volume switching valve 50, the counterbalance valve 40, and the high-pressure selection valve 60, and attached to the piston motor 1. The volume switching valve 50, the counterbalance valve 40, and the high-pressure selection valve 60 are provided with a spool (first spool 41, parallel to a second direction perpendicular to a first direction parallel to the rotation shaft 1a of the piston motor 1). Each has a second spool 51 and a third spool 61), and a high-pressure selection valve 60 is provided between the counterbalance valve 40 and the volume switching valve 50 when viewed from the first direction.

  In this configuration, the upstream counterbalance valve 40 through which the hydraulic oil from the pump 70 is guided through the supply / discharge ports P1 and P2, and the downstream volume switching valve 50 through which the hydraulic fluid is guided to the switching actuators 20 and 21 of the piston motor 1. , A high pressure selection valve 60 is provided. For this reason, the supply / discharge ports P1, P2 and the counterbalance valve 40 are arranged close to each other on one side (upper side) in the third direction, and the switching actuators 20, 21 and the volume switching valve 50 are connected to each other in the third direction. On the side (lower side). Therefore, the flow path (the first main path 32 and the second main path 33) that connects the counter balance valve 40 with the supply / discharge ports P1 and P2 can be shortened, and the flow path resistance is reduced. Further, the flow paths (the first switching path 22 and the second switching path 23) connecting the volume switching valve 50 and the switching actuators 20 and 21 can be configured to be short, and the flow path resistance is reduced. Further, by arranging the high-pressure selection valve 60 between the counterbalance valve 40 and the volume switching valve 50, the space in the valve housing 31 can be used efficiently. Therefore, the size of the valve housing 31 can be reduced while securing the flow rate of the passage formed in the valve housing 31.

  The hydraulic motor unit 100 further includes communication passages 66 and 67 that communicate the counterbalance valve 40 and the high-pressure selection valve 60, and the communication passages 66 and 67 have a flat cross section that extends in the first direction.

  In this configuration, the communication passages 66 and 67 have a cross-sectional shape extending in the vertical direction of the second direction in which a dead space is more likely to occur than in the second direction. For this reason, compared with the case where the width is uniform, the cross-sectional area of the flow channel can be increased by using the dead space. Therefore, the flow rate of the hydraulic oil returned to the supply side by the high-pressure selection valve 60 increases, and the occurrence of cavitation can be suppressed more reliably.

  In the hydraulic motor unit 100, at least one spool (the first spool 41, the second spool 51, and the third spool 61) of the counter balance valve 40, the high pressure selection valve 60, and the volume switching valve 50 is The position in the first direction is shifted from other spools (the first spool 41, the second spool 51, and the third spool 61).

  In the hydraulic motor unit 100, the counter balance valve 40 allows the flow of the hydraulic oil supplied to the piston motor 1 and the check valves 47 and 48 for shutting off the flow of the hydraulic oil discharged from the piston motor 1. The check valves 47 and 48 are provided between the counterbalance valve 40 and the high-pressure selection valve 60 when viewed from the first direction, and the check valves 47 and 48 are arranged so as to face forward in the first direction. The high pressure selection valve 60 is provided to be shifted from the check valves 47 and 48 toward the rear side in the first direction, and the volume switching valve 50 is provided to be shifted toward the front side in the first direction. Thus, it is provided to be shifted from the high pressure selection valve 60.

  In these configurations, the spools (the first spool 41, the second spool 51, and the third spool 61) are displaced and arranged in the first direction, so that the spools (the first spool 41, the second spool 51, Since the distance between the third spools 61) can be reduced, the valve housing 31 can be downsized.

  In the hydraulic motor unit 100 according to the modified example, the respective spools (the first spool 41, the second spool 51, and the third spool 61) of the counter balance valve 40, the high pressure selection valve 60, and the volume switching valve 50 are , Along the third direction.

  In this configuration, the accommodation holes (the first accommodation hole 41a, the second accommodation hole 51a, and the third accommodation hole 61a) for accommodating the respective spools (the first spool 41, the second spool 51, and the third spool 61) are formed in one mold. Therefore, the manufacturing cost can be reduced.

  As described above, the embodiment of the present invention has been described. However, the above embodiment is merely an example of the application of the present invention, and the technical scope of the present invention is not limited to the specific configuration of the above embodiment. Absent.

  DESCRIPTION OF SYMBOLS 1 ... Piston motor (hydraulic piston motor), 1a ... Rotary shaft, 7 ... Swash plate, 20, 21 ... Switching actuator, 30 ... Hydraulic motor control device, 31 ... Valve housing, 40 ... Counterbalance valve, 41 ... No. 1 spool, 47, 48 check valve, 50 volume switching valve, 51 second spool, 60 high pressure selection valve, 61 third spool, 66, 67 communication path, 70 pump (hydraulic pressure source), 100: hydraulic motor unit, P1, P2: supply / discharge port (external port)

Claims (5)

A hydraulic piston motor whose displacement changes according to the tilt angle of the swash plate,
A hydraulic motor control device that controls the flow of hydraulic fluid supplied to and discharged from the hydraulic piston motor,
The hydraulic piston motor has a switching actuator that changes the volume by driving the swash plate,
The hydraulic motor control device,
An external port to which hydraulic fluid is supplied from a hydraulic pressure source;
Hydraulic fluid is guided from the external port, and a counter balance valve that allows the operation of the hydraulic piston motor and maintains a stopped state of the hydraulic piston motor,
A volume switching valve for controlling the flow of the hydraulic fluid supplied to the switching actuator,
A high-pressure selection valve that returns the hydraulic fluid discharged from the hydraulic piston motor to the supply side when the hydraulic piston motor decelerates,
A single valve housing in which the external port is formed and houses the volume switching valve, the counterbalance valve, and the high pressure selector valve, and is attached to the hydraulic piston motor;
The volume switching valve, the counter balance valve, and the high-pressure selection valve each have a spool provided in parallel with a second direction perpendicular to a first direction parallel to the rotation axis of the hydraulic piston motor,
The hydraulic motor unit, wherein the high-pressure selection valve is provided between the counterbalance valve and the volume switching valve when viewed from the first direction. Further comprising a communication passage communicating the counter balance valve and the high-pressure selection valve,
The hydraulic motor unit according to claim 1, wherein the communication passage has a flat shape having a cross section extending in the first direction.   The spool of at least one of the counterbalance valve, the high-pressure selection valve, and the volume switching valve is arranged so that a position in the first direction is shifted from other spools. Item 3. The hydraulic motor unit according to item 1 or 2. The counter balance valve has a check valve that allows the flow of the hydraulic fluid supplied to the hydraulic piston motor and shuts off the flow of the hydraulic fluid discharged from the hydraulic piston motor,
The check valve is provided between the counterbalance valve and the high-pressure selection valve when viewed from the first direction, and is shifted from the spool of the counterbalance valve toward one side in the first direction. Provided,
The high-pressure selection valve is provided to be shifted from the check valve toward the other side in the first direction,
4. The hydraulic motor unit according to claim 3, wherein the volume switching valve is provided to be shifted from the high-pressure selection valve toward the one side in the first direction. 5.   The spool of each of the counterbalance valve, the high pressure selection valve, and the volume switching valve is arranged along a third direction perpendicular to each of the first direction and the second direction. Item 3. The hydraulic motor unit according to item 1 or 2.

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