JP2017096368A - Counterbalance valve and fluid pressure control device having counterbalance valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a counterbalance valve which can properly adjust a brake distance of a vehicle body, and a fluid pressure control device having the counterbalance valve.SOLUTION: A counterbalance valve 10 comprises: valve-side passages 14a, 14b which communicate with a direction changeover valve 3; motor-side passages 15a, 15b which communicate with a hydraulic motor 2; a control valve 11 which controls a flow of a working fluid between the valve-side passages 14a, 14b and the motor-side passages 15a, 15b when the direction changeover valve 3 is switched; pilot chambers 11a, 11b into which pilot pressure for controlling the control valve 11 is introduced; pilot passages 13a, 13b which make the valve-side passages 14a, 14b and the pilot chambers 11a, 11b communicate with each other; and flow rate control valves 12a, 12b which variably control a flow rate of the working fluid flowing in the pilot passages 13a, 13b.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a counter balance valve and a fluid pressure control device including the counter balance valve.

  In Patent Document 1, a counter balance valve is interposed between a hydraulic motor and a direction switching valve in a hydraulic motor drive circuit that constitutes a traveling device of a construction machine in order to suppress an impact that occurs when starting and stopping. The described drive circuit is described. In the counter balance valve described in Patent Document 1, an orifice is provided in a passage that connects an oil chamber defined at both ends of a plunger and a hydraulic passage that communicates with a hydraulic motor. In the counter balance valve described in Patent Document 1, the stroke speed of the plunger of the counter balance valve is determined by the orifice diameter. Specifically, increasing the orifice diameter increases the plunger stroke speed, and decreasing the orifice diameter decreases the plunger stroke speed.

Japanese Patent Laid-Open No. 06-147201

  Generally, the orifice diameter is set on the basis that the construction machine travels on a flat ground. However, if the Ophiris diameter is set on the basis of traveling on flat ground, the distance until the construction machine stops when the vehicle is stopped while traveling downhill is extended. Conversely, if the Ophiris diameter is set on the basis of traveling downhill, the construction machine will suddenly stop when attempting to stop while traveling on flat ground.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a counter balance valve capable of appropriately adjusting the braking distance of the vehicle body, and a fluid pressure control device including the counter balance valve. .

  A first invention is a counter balance valve provided in a flow path connecting a fluid pressure motor provided on a vehicle body and driven by a working fluid discharged from a pump, and a direction switching valve for switching a rotation direction of the fluid pressure motor. The flow of the working fluid between the valve side passage and the motor side passage when the direction switching valve is switched, and the valve side passage communicating with the direction switching valve, the motor side passage communicating with the fluid pressure motor, and A control valve for controlling, a pilot chamber to which a pilot pressure for controlling the control valve is guided, a pilot passage communicating the valve side passage and the pilot chamber, and a flow rate control for variably controlling the flow rate of the working fluid flowing through the pilot passage And a valve.

  In the first aspect of the invention, the counter balance valve includes a flow rate control valve that variably controls the flow rate of the hydraulic fluid flowing through the pilot passage, so that the flow rate of the hydraulic fluid flowing into or discharged from the pilot chamber of the control valve is adjusted. By doing so, the switching speed of the control valve can be adjusted. Thereby, the timing at which the control valve shuts off the communication between the fluid pressure motor and the pump can be adjusted as appropriate, so that the braking of the fluid pressure motor can be adjusted.

  According to a second aspect of the present invention, the flow rate control valve is controlled such that the flow path area is increased when the direction switching valve is switched from a position for operating the fluid pressure motor to a position for stopping the fluid pressure motor. It is characterized by that.

  In the second invention, when the flow control valve is switched from the position where the direction switching valve is operated to operate the fluid pressure motor to the position where the fluid pressure motor is stopped, the flow path area is increased. Thereby, the timing which a control valve interrupts | blocks communication with a fluid pressure motor and a pump can be advanced, and it can suppress that the braking distance of a vehicle body extends.

  The third invention is characterized in that the pilot chambers are respectively provided at both ends of the control valve, and the flow rate control valves are provided in the respective pilot passages for guiding the pilot pressure to the respective pilot chambers.

  In the third invention, since the switching speed of the control valve 11 can be adjusted regardless of which direction the fluid pressure motor operates, the braking distance of the vehicle body is set appropriately regardless of which direction the vehicle travels. Can be adjusted.

  The fourth invention is characterized in that the flow control valve is an electromagnetic switching valve.

  In the fourth invention, since the flow control valve is an electromagnetic switching valve, it is only necessary to switch the current ON and OFF. Therefore, control can be simplified.

  The fifth invention is characterized in that the flow control valve is a rotary valve driven by an electric motor.

  The sixth invention is characterized in that the flow control valve is an electromagnetic proportional control valve.

  In the fifth and sixth inventions, since an electric motor or an electromagnetic proportional control valve is used, fine control can be performed.

  According to a seventh aspect of the invention, the flow control valve has a stroke sensor that detects the amount of movement of the valve element.

  In the seventh aspect of the invention, the control can be performed more accurately by feeding back the amount of movement of the valve element detected by the stroke sensor.

  An eighth invention is a fluid pressure control device for controlling a fluid pressure motor, a pump for discharging a working fluid, a fluid pressure motor driven by a working fluid discharged from the pump, a pump and a fluid pressure motor Any one of the first to seventh inventions provided between the direction switching valve and the fluid pressure motor in the flow path. And a counter balance valve as described above.

  The ninth aspect of the invention further includes a neutral state detection unit that detects that the direction switching valve is in a neutral state, and an inclination angle detection unit that detects the inclination angle of the vehicle body, and the flow rate control valve is a neutral position detection unit When the neutral state is detected, the control is performed according to the inclination angle detected by the inclination angle detection unit.

  In the ninth aspect of the invention, the flow rate control valve is controlled according to the inclination angle of the vehicle body when the direction switching valve is in the neutral state. Therefore, the switching speed of the control valve when the hydraulic motor is stopped is set to the inclination of the vehicle body. It can be adjusted according to the corner. Therefore, the fluid pressure motor can be appropriately braked in a state where the vehicle body is inclined. Thereby, the braking distance of the vehicle body can be appropriately adjusted according to the state in which the vehicle body is inclined.

  The tenth aspect of the present invention further includes a flow rate detection unit that detects the flow rate of the working fluid flowing through the fluid pressure motor, and the flow rate control valve is controlled according to the flow rate detected by the flow rate detection unit.

  In the tenth invention, the flow rate control valve is controlled according to the flow rate detected by the flow rate detector, so that the switching speed of the control valve can be adjusted according to the rotational speed of the fluid pressure motor. Thereby, the braking distance of the vehicle body can be appropriately adjusted according to the rotational speed of the fluid pressure motor.

  The eleventh aspect of the invention further includes a differential pressure detection unit that detects a differential pressure between the supply side and the discharge side in the fluid pressure motor, and a rotation speed detection unit that detects the rotation number of the fluid pressure motor, and the flow control valve Is controlled in accordance with the differential pressure detected by the differential pressure detector and the rotational speed detected by the rotational speed detector.

  In the eleventh aspect, the operating state of the fluid pressure motor can be detected based on the differential pressure between the supply side and the discharge side of the fluid pressure motor and the rotation speed of the fluid pressure motor. Since the differential pressure between the supply side and the discharge side of the fluid pressure motor and the rotation speed of the fluid pressure motor have small measurement errors, the flow rate can be calculated with high accuracy. Therefore, the flow control valve can be controlled more accurately. Thereby, the braking distance of the vehicle body can be adjusted more appropriately according to the rotational speed of the fluid pressure motor.

  ADVANTAGE OF THE INVENTION According to this invention, the counter balance valve which can adjust the braking distance of a vehicle body appropriately, and the fluid-pressure control apparatus provided with this counter balance valve can be provided.

1 is a hydraulic circuit diagram of a hydraulic control device according to a first embodiment of the present invention. It is a hydraulic circuit diagram which shows the modification of the hydraulic control apparatus which concerns on 1st Embodiment of this invention. It is a hydraulic circuit diagram which shows the modification of the hydraulic control apparatus which concerns on 1st Embodiment of this invention. FIG. 5 is a hydraulic circuit diagram of a hydraulic control device according to a second embodiment of the present invention.

<First Embodiment>
Hereinafter, with reference to the drawings, a counter balance valve 10 and a fluid pressure control device 100 including the counter balance valve 10 according to a first embodiment of the present invention will be described. FIG. 1 is a hydraulic circuit diagram illustrating a counter balance valve 10 and a fluid pressure control device 100 including the counter balance valve 10 according to the first embodiment.

  The fluid pressure control device 100 is mounted on a vehicle body of a working machine that is driven by fluid pressure, such as a power shovel or a wheel loader. In the fluid pressure control apparatus 100, hydraulic oil is used as the working fluid, but other fluids such as working water may be used as the working fluid.

  As shown in FIG. 1, a fluid pressure control apparatus 100 includes a pump 1 that discharges hydraulic oil, a hydraulic motor 2 that functions as a hydraulic motor driven by the hydraulic oil discharged from the pump 1, a pump 1, and a hydraulic motor 2. The direction switching valve 3 for switching the rotation direction of the hydraulic motor 2, the supply channel 21 for connecting the pump 1 and the direction switching valve 3, the hydraulic motor 2 and the direction switching valve 3 are provided. Supply / discharge passages 22a and 22b to be connected and a remote control valve 5 for controlling the pilot pressure of the direction switching valve 3 are provided.

  The pump 1 is driven by engine power (not shown) and discharges hydraulic oil to the supply flow path 21. The pump 1 is a swash plate type axial piston pump. Although the pump 1 is shown as a fixed capacity type in FIG. 1, the pump 1 is not limited to this and may be a variable capacity type.

  The hydraulic motor 2 is a swash plate type axial piston motor having a fixed capacity, and is used as a traveling hydraulic motor. The hydraulic motor 2 is rotationally driven in response to the supply of hydraulic oil discharged from the pump 1. The hydraulic motor 2 is switched to forward rotation or reverse rotation by the direction switching valve 3. When the hydraulic motor 2 rotates forward, the work implement moves forward, and when the hydraulic motor 2 rotates reversely, the work implement moves backward. The hydraulic motor 2 is not limited to a swash plate type axial piston motor having a fixed capacity, but may be a swash plate type axial piston motor having a variable capacity.

  The hydraulic motor 2 is provided with a negative parking brake 2a that applies a braking force to the hydraulic motor 2 when stopped. The parking brake 2 a is connected to a counter balance valve 10 described later by a flow path 23. When the pressure in the flow path 23 exceeds a predetermined pressure (brake release pressure), the parking brake 2a releases the brake and allows the hydraulic motor 2 to rotate.

  The direction switching valve 3 has a forward position A that guides hydraulic oil discharged from the pump 1 to the supply flow path 21 to the hydraulic motor 2 through the supply / discharge flow path 22a, and hydraulic oil discharged from the pump 1 to the supply flow path 21. The reverse position B which leads to the hydraulic motor 2 through the supply / discharge passage 22b, and the neutral position C where the pump 1 and the hydraulic motor 2 communicate with the tank T are provided. The direction switching valve 3 is switched by hydraulic fluid (pilot pressure) supplied from the pilot pump 4 to the pilot chambers 3 a and 3 b through the remote control valve 5 when the crew of the work machine operates the remote control valve 5. Specifically, when the remote control valve 5 is operated to one side and the pilot pressure is supplied to the pilot chamber 3a, the direction switching valve 3 is switched to the forward position A, the remote control valve 5 is operated to the other side, and the pilot When the pressure is supplied to the pilot chamber 3b, the direction switching valve 3 is switched to the reverse position B. When the remote control valve 5 is in the neutral position, that is, when the pilot pressure is not acting on any of the pilot chambers 3a and 3b, the direction switching valve 3 is driven by the biasing force of the springs 3c provided on both sides of the direction switching valve 3. Neutral position C is reached. The pilot pressure supplied to the pilot chambers 3 a and 3 b is controlled according to the operation amount of the remote control valve 5.

  The remote control valve 5 includes a position detection sensor 5 a that detects the neutral state of the remote control valve 5. The position detection sensor 5a outputs a detection signal to the controller 40 when the operation lever of the remote control valve 5 is in the neutral position. When the remote control valve 5 is in a neutral state, the direction switching valve 3 is also in a neutral state. That is, the neutral state of the direction switching valve 3 can be detected by the position detection sensor 5a. The position detection sensor 5a corresponds to a neutral state detector that detects that the direction switching valve 3 is in a neutral state.

  The fluid pressure control device 100 further includes a counter balance valve 10 provided between the direction switching valve 3 and the hydraulic motor 2. The counter balance valve 10 is provided in the supply / discharge passages 22a and 22b.

  The counter balance valve 10 includes valve-side passages 14a and 14b communicating with the direction switching valve 3 through the supply / discharge passages 22a and 22b, and motor-side passages 15a and 15b communicating with the hydraulic motor 2 through the supply / discharge passages 22a and 22b. The control valve 11 that controls the flow of hydraulic fluid between the valve side passages 14a and 14b and the motor side passages 15a and 15b when the direction switching valve 3 is switched, and the pilot pressure for controlling the control valve 11 Pilot chambers 11a and 11b, pilot passages 13a and 13b communicating with the valve side passages 14a and 14b and the pilot chambers 11a and 11b, and hydraulic fluid provided in the pilot passages 13a and 13b and flowing through the pilot passages 13a and 13b. Flow rate control valves 12a and 12b that variably control the flow rate of the.

  The pilot chambers 11a and 11b are provided at both ends of the control valve 11, respectively. The pilot passages 13a and 13b branch from the valve side passages 14a and 14b, respectively, and communicate with the pilot chambers 11a and 11b.

  The control valve 11 communicates the valve-side passage 14a with the motor-side passage 15a and the passage 23, and operates the valve-side passage 14b with the motor-side passage 15b. An operating position E for communicating the valve side passage 14b with the motor side passage 15b and the flow path 23, and a neutral position F for blocking communication between the valve side passages 14a, 14b and the motor side passages 15a, 15b. .

  When the direction switching valve 3 is switched to the forward position A, the control valve 11 guides the hydraulic oil discharged from the pump 1 to the pilot chamber 11a through the supply / discharge passage 22a, the valve side passage 14a, and the pilot passage 13a. As a result, the operation position D is switched. In addition, when the direction switching valve 3 is switched to the reverse position B, the control valve 11 allows the hydraulic oil discharged from the pump 1 to pass through the supply / discharge passage 22b, the valve side passage 14b, and the pilot passage 13b. Is switched to the operation position E. Further, when the direction switching valve 3 is switched to the neutral position C, the control valve 11 allows the hydraulic oil in the pilot chambers 11a and 11b to flow through the pilot passages 13a and 13b, the valve side passages 14a and 14b, and the supply / discharge passage. It is discharged to the tank T through 22a and 22b and switched to the neutral position F by the urging force of the springs 11c provided on both sides.

  The flow control valves 12a and 12b are electromagnetic proportional control valves including an electromagnetic proportional solenoid. When it is detected that the direction switching valve 3 is in the neutral state, the flow rate control valves 12a and 12b change the flow path area based on the current applied from the controller 40, thereby allowing the pilot passages 13a and 13b to flow. Controls the flow rate of flowing hydraulic oil. That is, the flow control valves 12a and 12b function as variable throttles. The flow rate control valves 12a and 12b are such that the flow area (throttle) is minimized when no current is applied from the controller 40, and the flow area (throttle) increases as the current applied from the controller 40 increases. Controlled. The flow rate control valves 12a and 12b control the pressure of the hydraulic oil in the pilot chambers 11a and 11b by controlling the flow rate of the hydraulic oil flowing through the pilot passages 13a and 13b, and adjust the switching speed of the control valve 11.

  The fluid pressure control device 100 includes an inclination angle sensor 30 as an inclination angle detection unit that detects the inclination angle of the vehicle body of the work machine, and a flow rate sensor 50 as a flow rate detection unit that detects the flow rate of hydraulic oil flowing through the hydraulic motor 2. Are further provided.

  The tilt angle sensor 30 detects the tilt angle in the front-rear direction with respect to the horizontal plane of the vehicle body of the work machine, and outputs the detected tilt angle to the controller 40.

  The flow sensor 50 is provided in the supply / discharge channel 22 a, detects the flow rate of the hydraulic oil flowing through the supply / discharge channel 22 a, and outputs the detected flow rate to the controller 40. The flow sensor 50 may be provided in the supply / discharge flow path 22b.

  Operations of the counter balance valve 10 and the fluid pressure control device 100 configured as described above will be described.

  First, a case where the work machine is moved forward will be described.

  When the crew member operates the remote control valve 5 toward one side, the hydraulic oil discharged from the pilot pump 4 is supplied to the pilot chamber 3a through the remote control valve 5. At this time, a pilot pressure corresponding to the operation amount of the remote control valve 5 is supplied to the pilot chamber 3a. As a result, the direction switching valve 3 switches to the forward position A, and the hydraulic oil discharged from the pump 1 flows from the supply passage 21 into the valve side passage 14a of the counter balance valve 10 through the supply / discharge passage 22a.

  Part of the hydraulic oil that has flowed into the valve-side passage 14a of the counter balance valve 10 flows into the pilot chamber 11a through the pilot passage 13a. As a result, the control valve 11 is switched to the operating position D. At this time, since the direction switching valve 3 is not in a neutral state, no current is applied from the controller 40 to the flow control valve 12a. Therefore, the flow area of the flow control valve 12a is minimized. For this reason, since the flow of the hydraulic oil flowing through the pilot passage 13a is restricted by the flow rate control valve 12a, it gradually flows into the pilot chamber 11a. As a result, the control valve 11 is gradually switched to the operating position D.

  When the control valve 11 is switched to the operating position D, the hydraulic oil discharged from the pump 1 is supplied to the supply passage 21, the direction switching valve 3, the supply / discharge passage 22a, the valve side passage 14a, the control valve 11, and the motor side passage. 15a and the supply / discharge flow path 22a are supplied to the hydraulic motor 2. At the same time, the hydraulic oil discharged from the pump 1 is supplied from the control valve 11 through the flow path 23 to the parking brake 2a, and the parking brake 2a is released. As a result, the hydraulic motor 2 rotates forward and the work implement moves forward.

  The flow rate of the hydraulic oil flowing through the supply / discharge flow path 22 a is detected by the flow rate sensor 50, and the detected flow rate is output to the controller 40. The hydraulic oil discharged from the hydraulic motor 2 returns to the tank T through the supply / discharge passage 22b, the motor side passage 15b, the control valve 11, the valve side passage 14b, the supply / discharge passage 22b, and the direction switching valve 3. It is.

  Next, a case where the work machine stops from a state where it is moving forward will be described.

  When the crew member returns the remote control valve 5 to the neutral position, the hydraulic oil in the pilot chamber 3 a is discharged to the tank T through the remote control valve 5. Thereby, the direction switching valve 3 is returned to the neutral position C by the urging force of the spring 3 c provided in the direction switching valve 3.

  When the direction switching valve 3 is returned to the neutral position C, the valve side passage 14 a communicates with the tank T through the supply / discharge passage 22 a and the direction switching valve 3. As a result, the hydraulic oil in the pilot chamber 11a is discharged to the tank T through the pilot passage 13a, the valve side passage 14a, the supply / discharge passage 22a, and the direction switching valve 3.

  When the remote control valve 5 is returned to the neutral position, the position detection sensor 5a provided on the remote control valve 5 detects that the operation lever of the remote control valve 5 is in the neutral state, and outputs a detection signal to the controller 40. When the detection signal is input from the position detection sensor 5a, the controller 40 applies a current corresponding to the inclination angle detected by the inclination angle sensor 30 to the flow control valve 12a. Specifically, if the work implement is in a horizontal state, the controller 40 does not apply a current to the flow control valve 12a, and if the work implement is tilted forward and downward, the inclination angle of the vehicle body is large. From time to time, a large current is applied to the flow control valve 12a. That is, when the vehicle body is tilted forward and downward, a large current is applied to the flow control valve 12a, and the flow passage area of the flow control valve 12a increases. As a result, the resistance due to the restriction of the flow control valve 12a with respect to the flow of hydraulic oil discharged from the pilot chamber 11a is reduced, and the switching speed of the control valve 11 is increased. Therefore, when the vehicle body is tilted forward and downward, the control valve 11 switches from the operating position D to the neutral position F earlier than when the vehicle body is in a horizontal state. For this reason, when the vehicle body is inclined forwardly downward, that is, when the work implement is traveling forward on a downhill, the communication between the valve side passage 14a and the motor side passage 15a is such that the vehicle body is in a horizontal state. As compared with a certain case, it is shut off earlier, and the braking force for the hydraulic motor 2 is generated earlier. In this way, the fluid pressure control device 100 can quickly generate the braking force for the hydraulic motor 2 when the work implement is traveling forward on a downhill, and therefore the braking distance when the work implement is stopped. Can be shortened.

  Further, the flow rate of the supply / discharge flow path 22 a detected by the flow rate sensor 50 is input to the controller 40. When the detection signal is input from the position detection sensor 5a, the controller 40 applies a current corresponding to the flow rate detected by the flow rate sensor 50 to the flow rate control valve 12a. Specifically, the controller 40 applies a larger current to the flow control valve 12a as the flow rate increases. Since the flow rate detected by the flow sensor 50 is equal to the flow rate of the hydraulic oil supplied to the hydraulic motor 2, the rotation speed of the hydraulic motor 2 is faster if the flow rate detected by the flow sensor 50 is large. That is, as the rotational speed of the hydraulic motor 2 increases, a larger current is applied to the flow control valve 12a and the flow path area increases. Therefore, since the hydraulic oil in the pilot chamber 11a is discharged without being affected by the restriction of the flow control valve 12a, the switching speed of the control valve 11 is increased. As a result, when the rotational speed of the hydraulic motor 2 is fast, the switching speed of the control valve 11 is fast, so that the control valve 11 is quickly switched from the operating position D to the neutral position F. Therefore, when the rotation speed of the hydraulic motor 2 is high, that is, when the speed of the work machine is high, the switching speed of the control valve 11 is high, so that the communication between the valve side passage 14a and the motor side passage 15a is the hydraulic motor. As compared with the case where the rotational speed of 2 is slow (when the speed of the working machine is slow), the motor is shut off earlier, and the braking force for the hydraulic motor 2 is generated earlier. As described above, when the speed of the work implement is high, the fluid pressure control device 100 can generate the braking force against the hydraulic motor 2 quickly, and thus the braking distance of the work implement can be shortened.

  Next, a case where the work machine is moved backward will be described.

  When the crew operates the remote control valve 5 toward the other side, the hydraulic oil discharged from the pilot pump 4 is supplied to the pilot chamber 3 b through the remote control valve 5. At this time, the pilot pressure corresponding to the operation amount of the remote control valve 5 is supplied to the pilot chamber 3b. Thereby, the direction switching valve 3 is switched to the reverse position B, and the hydraulic oil discharged from the pump 1 flows from the supply passage 21 into the valve side passage 14b of the counter balance valve 10 through the supply / discharge passage 22b.

  Part of the hydraulic oil that has flowed into the valve-side passage 14b of the counter balance valve 10 flows into the pilot chamber 11b through the pilot passage 13b. As a result, the control valve 11 is switched to the operating position E. At this time, since the direction switching valve 3 is not in a neutral state, no current is applied from the controller 40 to the flow control valve 12b. Therefore, the flow path area of the flow control valve 12b is minimized. For this reason, since the flow of the hydraulic oil flowing through the pilot passage 13b is restricted by the flow rate control valve 12b, it gradually flows into the pilot chamber 11b. As a result, the control valve 11 is switched to the gentle operation position E.

  When the control valve 11 is switched to the operation position E, the hydraulic oil discharged from the pump 1 is supplied to the supply passage 21, the direction switching valve 3, the supply / discharge passage 22b, the valve side passage 14b, the control valve 11, and the motor side passage. It is supplied to the hydraulic motor 2 through 15b and the supply / discharge passage 22b. At the same time, the hydraulic oil discharged from the pump 1 is supplied from the control valve 11 through the flow path 23 to the parking brake 2a, and the parking brake 2a is released. As a result, the hydraulic motor 2 rotates in the reverse direction and the work implement moves backward.

  The hydraulic oil discharged from the hydraulic motor 2 returns to the tank T through the supply / discharge passage 22a, the motor side passage 15a, the control valve 11, the valve side passage 14a, the supply / discharge passage 22a, and the direction switching valve 3. It is. At this time, the flow rate of the hydraulic oil flowing through the supply / discharge channel 22 a is detected by the flow sensor 50, and the detected flow rate is output to the controller 40.

  Next, a case where the work machine is stopped from a state of moving backward will be described.

  When the crew member returns the remote control valve 5 to the neutral position, the hydraulic oil in the pilot chamber 3 b is discharged to the tank T through the remote control valve 5. Thereby, the direction switching valve 3 is returned to the neutral position C by the urging force of the spring 3 c provided in the direction switching valve 3.

  When the direction switching valve 3 is returned to the neutral position C, the valve side passage 14 b communicates with the tank T through the supply / discharge passage 22 b and the direction switching valve 3. Thereby, the hydraulic oil in the pilot chamber 11 b is discharged to the tank T through the pilot passage 13 b, the valve side passage 14 b, the supply / discharge passage 22 b and the direction switching valve 3.

  When the remote control valve 5 is returned to the neutral position, the position detection sensor 5a provided on the remote control valve 5 detects that the operation lever of the remote control valve 5 is in the neutral state, and outputs a detection signal to the controller 40. When the detection signal is input from the position detection sensor 5a, the controller 40 applies a current corresponding to the inclination angle detected by the inclination angle sensor 30 to the flow control valve 12b. Specifically, if the work implement is in a horizontal state, the controller 40 does not apply a current to the flow rate control valve 12b, and if the work implement is inclined backward and downward, the inclination angle of the vehicle body is large. From time to time, a large current is applied to the flow control valve 12b. That is, when the vehicle body is inclined rearward and downward, a large current is applied to the flow control valve 12b, and the flow path area increases. As a result, the resistance due to the restriction of the flow rate control valve 12b with respect to the flow of hydraulic oil discharged from the pilot chamber 11b is reduced, so that the switching speed of the control valve 11 is increased. Therefore, when the vehicle body is inclined downward and rearward, the control valve 11 switches from the operating position E to the neutral position F faster than when the vehicle body is in a horizontal state. For this reason, when the vehicle body is inclined rearwardly downward, that is, when the work machine is traveling backward on a downhill, the communication between the valve side passage 14b and the motor side passage 15b causes the vehicle body to be in a horizontal state. As compared with a certain case, it is shut off earlier, and the braking force for the hydraulic motor 2 is generated earlier. In this way, the fluid pressure control device 100 can quickly generate the braking force for the hydraulic motor 2 when the work implement is traveling backward on a downhill, so that the braking distance when the work implement is stopped is low. Can be shortened.

  Further, the flow rate of the supply / discharge flow path 22 a detected by the flow rate sensor 50 is input to the controller 40. When the detection signal is input from the position detection sensor 5a, the controller 40 applies a current corresponding to the flow rate detected by the flow rate sensor 50 to the flow rate control valve 12b. Specifically, the controller 40 applies a larger current to the flow control valve 12b as the flow rate increases. Since the flow rate detected by the flow sensor 50 is equal to the flow rate of the hydraulic oil supplied to the hydraulic motor 2, the rotation speed of the hydraulic motor 2 is faster if the flow rate detected by the flow sensor 50 is large. That is, as the rotational speed of the hydraulic motor 2 increases, a larger current is applied to the flow control valve 12b and the flow path area increases. Accordingly, since the hydraulic oil in the pilot chamber 11b is discharged without being affected by the restriction of the flow control valve 12b, the switching speed of the control valve 11 is increased. As a result, when the rotational speed of the hydraulic motor 2 is fast, the switching speed of the control valve 11 is fast, so that the control valve 11 is quickly switched from the operating position E to the neutral position F. Therefore, when the rotation speed of the hydraulic motor 2 is high, that is, when the speed of the work machine is high, the switching speed of the control valve 11 is high, and therefore the communication between the valve side passage 14b and the motor side passage 15b is the hydraulic motor. As compared with the case where the rotational speed of 2 is slow (when the speed of the working machine is slow), the motor is shut off earlier, and the braking force for the hydraulic motor 2 is generated earlier. In this way, when the speed of the work implement is high, the fluid pressure control device 100 can generate the braking force against the hydraulic motor 2 quickly, so that the brake distance of the work implement can be shortened.

  Although the flow rate control valves 12a and 12b have been described by taking the electromagnetic proportional control valve as an example, they may be two-position electromagnetic switching valves. In this case, a threshold value may be provided for the tilt angle detected by the tilt angle sensor 30 and the flow rate detected by the flow rate sensor 50, and the position of the electromagnetic switching valve may be switched when the threshold value is exceeded. As a result, only the ON / OFF control of the positions of the flow control valves 12a, 12b is required, so that the control in the controller 40 can be simplified.

  Further, the flow control valves 12a and 12b may be rotary valves 60a and 60b driven by an electric motor as shown in FIG. In this case, highly accurate control can be performed by detecting the rotation angle with a rotation angle sensor or the like and performing feedback control. A stepping motor or the like is employed as the electric motor, but any type of electric motor may be used as long as the rotation angle can be detected. Furthermore, as shown in FIG. 3, the flow rate control valves 12a and 12b may be provided with a stroke sensor 12c that detects the stroke of the valve body of the flow rate control valves 12a and 12b. By controlling the stroke of the valve element detected by the stroke sensor 12c while feeding back, more accurate control can be performed.

  In the fluid pressure control device 100, the controller 40 controls the flow control valves 12a and 12b. However, the flow control valves 12a and 12b may be variable throttles that are manually operated. Even with such a configuration, the switching speed of the control valve 11 can be adjusted as appropriate.

  Further, the fluid pressure control device 100 may be configured to control the flow control valves 12a and 12b only by the inclination angle detected by the inclination angle sensor 30 or only by the flow rate detected by the flow sensor 50. Furthermore, the flow control valves 12a and 12b may be configured to include only the flow control valve 12a on the forward side.

  Further, the controller 40 may control the flow rate control valves 12a and 12b including not only when the vehicle body is in the front-lowering state but also when the vehicle body is in the front-up state. For example, when the direction switching valve 3 is in the neutral state, a constant current may be applied to the flow control valves 12a and 12b, and the applied current may be increased or decreased according to the inclination angle of the vehicle body.

  According to the above 1st Embodiment, there exist the following effects.

  The counter balance valve 10 includes flow control valves 12a and 12b that variably control the flow rate of the hydraulic oil flowing through the pilot passages 13a and 13b. Therefore, the switching speed of the control valve 11 can be adjusted by controlling the flow rate of the hydraulic oil flowing into the pilot chambers 11a and 11b of the control valve 11 or discharged from the pilot chambers 11a and 11b. Thereby, since the timing at which the control valve 11 cuts off the communication between the hydraulic motor 2 and the pump 1 can be adjusted as appropriate, the braking of the hydraulic motor 2 can be adjusted. Therefore, the braking distance of the vehicle body can be adjusted appropriately.

  Furthermore, the flow rate control valves 12a and 12b are moved by the inclination angle sensor 30 when the direction switching valve 3 is returned from the forward position A or the reverse position B where the hydraulic motor 2 is operated to the neutral position C where the hydraulic motor 2 is stopped. The flow of hydraulic oil discharged from the pilot chambers 11a and 11b is controlled according to the detected inclination angle and the flow rate detected by the flow rate sensor 50.

  When the vehicle body is tilted forward and downward, the braking distance increases due to the weight of the work implement. However, the fluid pressure control device 100 includes a position detection sensor 5a that detects that the direction switching valve 3 is in a neutral state and an inclination angle sensor 30 that detects the inclination angle of the vehicle body, and the flow control valves 12a and 12b. Is controlled according to the inclination angle detected by the inclination angle sensor 30 when the neutral state is detected by the position detection sensor 5a. Thereby, when stopping the hydraulic motor 2, the switching speed of the control valve 11 is adjusted according to the inclination angle detected by the inclination angle sensor 30, and the timing at which the communication between the hydraulic motor 2 and the pump 1 is cut off. adjust. Therefore, the fluid pressure control device 100 can generate a braking force against the hydraulic motor 2 according to the inclination angle of the vehicle body by the counter balance valve 10, so that even when the vehicle body is inclined forward and downward, The vehicle body can be braked at an appropriate braking distance.

  Furthermore, the fluid pressure control device 100 includes a flow sensor 50 that detects the flow rate of the hydraulic oil flowing through the hydraulic motor 2, and the flow control valves 12 a and 12 b are controlled according to the flow rate detected by the flow sensor 50. As a result, when stopping the hydraulic motor 2, the switching speed of the control valve 11 is adjusted according to the flow rate detected by the flow sensor 50 to adjust the timing for disconnecting the communication between the hydraulic motor 2 and the pump 1. . Therefore, the fluid pressure control device 100 can generate a braking force for the hydraulic motor 2 in accordance with the speed of the work implement by the counter balance valve 10. It is possible to brake with a simple braking distance.

Second Embodiment
With reference to FIG. 4, a fluid pressure control apparatus 200 according to a second embodiment of the present invention will be described. Below, it demonstrates centering on a different point from 1st Embodiment mentioned above, the same code | symbol is attached | subjected to the structure same as the fluid pressure control apparatus 100 of 1st Embodiment, and description is abbreviate | omitted.

  In the first embodiment, the flow rate of the hydraulic oil flowing to the hydraulic motor 2 is detected by the flow sensor 50, whereas in the second embodiment, the flow rate of the hydraulic oil flowing to the hydraulic motor 2 is detected from the differential pressure gauge 70 and the rotational speed sensor 80. It differs in the point calculated by. This will be specifically described below.

  The fluid pressure control device 200 includes a differential pressure gauge 70 as a differential pressure detection unit that detects a differential pressure between a supply side and a discharge side in the hydraulic motor 2 and a rotation as a rotation number detection unit that detects the rotation number of the hydraulic motor 2. A number sensor 80. The differential pressure gauge 70 detects the pressure in the supply / discharge flow path 22 a and the supply / discharge flow path 22 b and outputs the difference between them to the controller 40. The rotation speed sensor 80 is provided in the vicinity of the rotation shaft of the hydraulic motor 2, detects the rotation speed of the rotation shaft, and outputs the rotation speed of the hydraulic motor 2 to the controller 40.

  In the controller 40, a map indicating the relationship between the differential pressure detected in advance by the differential pressure gauge 70 and the volumetric efficiency of the hydraulic motor 2 is stored. The flow rate of the hydraulic oil flowing through the hydraulic motor 2 can be obtained by the equation “flow rate = displacement volume × rotational speed × volumetric efficiency”. The controller 40 calculates the flow rate of the hydraulic motor 2 based on the rotational speed detected by the rotational speed sensor 80, the differential pressure detected by the differential pressure gauge 70, and the map described above. The flow rate control valves 12a and 12b are controlled by the flow rate thus obtained in the same manner as in the first embodiment. Instead of the configuration by the differential pressure gauge 70, pressure gauges may be installed on the supply side and the discharge side in the hydraulic motor 2, and control may be performed based on the pressure difference detected by these pressure gauges.

  According to the above 2nd Embodiment, in addition to the effect of 1st Embodiment, there exist the following effects.

  Since the differential pressure gauge 70 and the rotation speed sensor 80 have a measurement error smaller than that of the flow rate sensor 50, the flow rate can be calculated with high accuracy. Therefore, the flow control valves 12a and 12b can be controlled more accurately. Thereby, according to the rotational speed of the hydraulic motor 2, the braking distance of a vehicle body can be adjusted more appropriately.

  The configuration, operation, and effect of the embodiment of the present invention configured as described above will be described together.

  The counter balance valve 10 is configured so that the valve side passages 14a and 14b communicating with the direction switching valve 3, the motor side passages 15a and 15b communicating with the fluid pressure motor (hydraulic motor 2), and the direction switching valve 3 are switched. A control valve 11 for controlling the flow of hydraulic oil between the valve side passages 14a, 14b and the motor side passages 15a, 15b; pilot chambers 11a, 11b to which pilot pressure for controlling the control valve 11 is guided; Pilot passages 13a and 13b communicating with the side passages 14a and 14b and the pilot chambers 11a and 11b, and flow rate control valves 12a and 12b for variably controlling the flow rate of the hydraulic fluid flowing through the pilot passages 13a and 13b are provided. And

  According to this configuration, the counter balance valve 10 includes the flow rate control valves 12a and 12b that variably control the flow rate of the hydraulic oil flowing through the pilot passages 13a and 13b. Therefore, the counter balance valve 10 flows into the pilot chambers 11a and 11b of the control valve 11 or pilots The switching speed of the control valve 11 can be adjusted by adjusting the flow rate of the hydraulic oil discharged from the chambers 11a and 11b. Thereby, since the timing at which the control valve 11 cuts off the communication between the fluid pressure motor (hydraulic motor 2) and the pump 1 can be adjusted as appropriate, the braking of the fluid pressure motor (hydraulic motor 2) can be adjusted. . Therefore, the braking distance of the vehicle body can be adjusted appropriately.

  Further, the flow control valves 12a and 12b are positions where the direction switching valve 3 stops the fluid pressure motor (hydraulic motor 2) from a position (forward position A or reverse position B) where the fluid pressure motor (hydraulic motor 2) operates. When switched to the neutral position C), the flow path area is controlled to be large.

  According to this configuration, the flow control valves 12a and 12b are moved from the position (forward position A or reverse position B) where the direction switching valve 3 operates to operate the fluid pressure motor (hydraulic motor 2) to the fluid pressure motor (hydraulic motor 2). ) Is switched to a position (neutral position C) to stop the flow path area increases. Thereby, the timing which the control valve 11 interrupts | blocks communication with a fluid pressure motor (hydraulic motor 2) and the pump 1 can be advanced, and it can suppress that the braking distance of a vehicle body extends.

  The counter balance valve 10 is provided with pilot chambers 11a and 11b at both ends of the control valve 11, and the flow control valves 12a and 12b are respectively pilot passages for introducing pilot pressure to the pilot chambers 11a and 11b. It is provided in 13a, 13b.

  According to this configuration, since the switching speed of the control valve 11 can be adjusted regardless of which direction the fluid pressure motor (hydraulic motor 2) operates, the vehicle body travels in any direction. The braking distance can be adjusted appropriately.

  Further, the counter balance valve 10 is characterized in that the flow control valves 12a and 12b are electromagnetic switching valves.

  According to this configuration, since the flow control valves 12a and 12b are electromagnetic switching valves, it is only necessary to switch the current ON and OFF. Therefore, control can be simplified.

  The counter balance valve 10 is characterized in that the flow control valves 12a and 12b are rotary valves 60a and 60b driven by an electric motor.

  Further, the counter balance valve 10 is characterized in that the flow control valves 12a and 12b are electromagnetic proportional control valves.

  According to these configurations, since an electric motor or an electromagnetic proportional control valve is used, fine control can be performed.

  Further, the counter balance valve 10 is characterized in that the flow rate control valves 12a and 12b further include a stroke sensor 12c for detecting the movement amount of the valve body.

  According to this configuration, it is possible to perform control more accurately by feeding back the amount of movement of the valve element detected by the stroke sensor 12c.

  The fluid pressure control device 100 includes a pump 1 that discharges hydraulic oil, a fluid pressure motor (hydraulic motor 2) that is driven by the hydraulic oil discharged from the pump 1, and a pump 1 and a fluid pressure motor (hydraulic motor 2). A direction switching valve 3 that is provided in the flow path to be connected and switches the rotation direction of the fluid pressure motor (hydraulic motor 2), and a counter that is provided between the direction switching valve 3 and the fluid pressure motor (hydraulic motor 2) in the flow path. The balance valve 10 is provided.

  Further, the fluid pressure control device 100 includes a neutral state detection unit (position detection sensor 5a) that detects that the direction switching valve 3 is in a neutral state, and an inclination angle detection unit (inclination angle sensor 30) that detects the inclination angle of the vehicle body. ), And the flow rate control valves 12a and 12b are detected by the inclination angle detection unit (inclination angle sensor 30) when the neutral position detection unit (position detection sensor 5a) detects the neutral state. It is controlled according to.

  According to this configuration, the flow control valves 12a and 12b are controlled according to the inclination angle of the vehicle body when the direction switching valve 3 is in the neutral state, and therefore when the fluid pressure motor (hydraulic motor 2) stops. The switching speed of the control valve 11 can be adjusted according to the inclination angle of the vehicle body. Therefore, the fluid pressure motor (hydraulic motor 2) can be appropriately braked in a state where the vehicle body is inclined. Thereby, the braking distance of the vehicle body can be appropriately adjusted according to the state in which the vehicle body is inclined.

  The fluid pressure control device 100 further includes a flow rate detection unit (flow rate sensor 50) that detects the flow rate of the hydraulic oil flowing through the fluid pressure motor (hydraulic motor 2), and the flow rate control valves 12a and 12b include the flow rate detection unit ( The flow rate is controlled in accordance with the flow rate detected by the flow rate sensor 50).

  According to this configuration, the flow rate control valves 12a and 12b are controlled according to the flow rate detected by the flow rate detection unit (flow rate sensor 50), so that the switching speed of the control valve 11 is set to the fluid pressure motor (hydraulic motor 2). It can be adjusted according to the rotation speed of. Thereby, the braking distance of the vehicle body can be appropriately adjusted according to the rotational speed of the fluid pressure motor (hydraulic motor 2).

  The fluid pressure control device 100 includes a differential pressure detection unit (differential pressure gauge 70) that detects a differential pressure between the supply side and the discharge side in the fluid pressure motor (hydraulic motor 2), and a fluid pressure motor (hydraulic motor 2). A rotational speed detection unit (rotational speed sensor 80) for detecting the rotational speed, and the flow rate control valves 12a and 12b include a differential pressure and rotational speed detection unit (detected by the differential pressure detection unit (differential pressure gauge 70)). It is controlled according to the rotational speed detected by the rotational speed sensor 80).

  According to this configuration, based on the differential pressure between the supply side and the discharge side in the fluid pressure motor (hydraulic motor 2) and the rotation speed of the fluid pressure motor (hydraulic motor 2), the fluid pressure motor (hydraulic motor 2) The operating state can be detected. Since the differential pressure between the supply side and the discharge side in the fluid pressure motor (hydraulic motor 2) and the rotation speed of the fluid pressure motor (hydraulic motor 2) have small measurement errors, the flow rate can be calculated with high accuracy. Therefore, the flow control valves 12a and 12b can be controlled more accurately. Thereby, the braking distance of the vehicle body can be adjusted more appropriately according to the rotational speed of the fluid pressure motor (hydraulic motor 2).

  The embodiment of the present invention has been described above. However, the above embodiment only shows a part of application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.

  For example, in each of the above embodiments, an oil temperature sensor that detects the oil temperature may be provided in the supply / discharge channels 22a and 22b. Since the viscosity of the hydraulic oil can be calculated from the detected oil temperature, it can be controlled with higher accuracy by controlling the flow rate control valves 12a and 12b using a correction coefficient (or map) corresponding to the viscosity.

  In each of the above embodiments, the hydraulic motor 2 has been described as an example for traveling, but may be used for turning.

  As a configuration for detecting the neutral state of the direction switching valve 3, a sensor for detecting the position of the valve body of the direction switching valve 3 may be provided. Alternatively, the neutral state of the direction switching valve 3 may be detected by detecting the pressure of the pilot flow path communicating with the pilot chambers 3a and 3b or the pilot chambers 3a and 3b.

DESCRIPTION OF SYMBOLS 10 ... Counter balance valve, 100, 200 ... Fluid pressure control apparatus, 1 ... Pump, 2 ... Fluid pressure motor (hydraulic motor), 3 ... Direction switch valve, 3a, 3b ... Pilot chamber, 5 ... remote control valve, 5a ... position detection sensor (neutral state detection unit), 11 ... control valve, 11a, 11b ... pilot chamber, 12a, 12b ... flow control valve , 12c: Stroke sensor, 13a, 13b ... Pilot passage, 14a, 14b ... Valve side passage, 15a, 15b ... Motor side passage, 21 ... Supply flow passage, 22a, 22b ... Supply / exhaust flow path, 30 ... tilt angle sensor (tilt angle detector), 40 ... controller, 50 ... flow sensor (flow rate detector), 60a, 60b ... rotary valve, 70 ...・ Differential pressure gauge (Differential pressure detector) 80 ... Rotation speed sensor (rotational speed detector)

Claims (11)

A counter balance valve provided in a flow path connecting a fluid pressure motor provided in a vehicle body and driven by a working fluid discharged from a pump, and a direction switching valve for switching a rotation direction of the fluid pressure motor;
A valve side passage communicating with the direction switching valve;
A motor side passage communicating with the fluid pressure motor;
A control valve for controlling the flow of the working fluid between the valve side passage and the motor side passage when the direction switching valve is switched;
A pilot chamber into which a pilot pressure for controlling the control valve is guided;
A pilot passage communicating the valve side passage and the pilot chamber;
And a flow control valve that variably controls the flow rate of the working fluid flowing through the pilot passage.   The flow rate control valve is controlled so that a flow path area is increased when the direction switching valve is switched from a position for operating the fluid pressure motor to a position for stopping the fluid pressure motor. The counter balance valve according to claim 1. The pilot chambers are provided at both ends of the control valve,
3. The counter balance valve according to claim 1, wherein the flow control valve is provided in each of the pilot passages that guides a pilot pressure to each of the pilot chambers.   4. The counter balance valve according to claim 1, wherein the flow control valve is an electromagnetic switching valve.   4. The counter balance valve according to claim 1, wherein the flow control valve is a rotary valve driven by an electric motor.   4. The counter balance valve according to claim 1, wherein the flow control valve is an electromagnetic proportional control valve.   The counter flow control valve according to claim 6, wherein the flow control valve has a stroke sensor that detects a moving amount of the valve body. A fluid pressure control device for controlling the fluid pressure motor,
The pump for discharging the working fluid;
The fluid pressure motor driven by the working fluid discharged from the pump;
Provided in a flow path connecting the pump and the fluid pressure motor, the direction switching valve for switching the rotation direction of the fluid pressure motor;
A fluid pressure control device comprising: the counter balance valve according to claim 1 provided between the direction switching valve and the fluid pressure motor in the flow path. A neutral state detector for detecting that the direction switching valve is in a neutral state;
An inclination angle detection unit for detecting an inclination angle of the vehicle body,
9. The fluid according to claim 8, wherein the flow rate control valve is controlled according to an inclination angle detected by the inclination angle detection unit when the neutral state is detected by the neutral position detection unit. Pressure control device. A flow rate detection unit for detecting a flow rate of the working fluid flowing through the fluid pressure motor;
The fluid pressure control device according to claim 8 or 9, wherein the flow rate control valve is controlled according to the flow rate detected by the flow rate detection unit. A differential pressure detector for detecting a differential pressure between the supply side and the discharge side in the fluid pressure motor;
A rotation speed detection unit for detecting the rotation speed of the fluid pressure motor,
The said flow control valve is controlled according to the said differential pressure detected by the said differential pressure | voltage detection part, and the said rotation speed detected by the said rotation speed detection part, The Claim 8 or 9 characterized by the above-mentioned. Fluid pressure control device.

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