JP2017219118A - Hydraulic circuit control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic circuit control system capable of reducing pressure loss due to pressure oil discharged from an actuator for a work machine.SOLUTION: A hydraulic circuit is provided with a selector valve 41 configured to select between a communication state and a cut-off state of a first pipe conduit L12 connecting between a first actuator 12 and a first direction selector valve 14 and a second pipe conduit L22 connecting between a second actuator 22 and a second direction selector valve 24. In a case where the first actuator 12 is operated and the second actuator 22 is not operated, or in a case equivalent to the above case, the first pipe conduit L12 and the second pipe conduit L22 are changed from the cut-off state to the communication state by the selector valve 41.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a hydraulic circuit including an actuator for operating a plurality of work machines and a hydraulic circuit control system including a control device for the hydraulic circuit.

  There is a technical method that can reduce the pressure loss and increase the flow rate without increasing the diameter of the conduit for the hydraulic actuator for work implements when switching from the long boom mode to the short boom mode of the work machine with a boom. It has been proposed (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 2004-092706

  However, there is still room for improvement with respect to the pressure loss according to the length of the pipe line from the hydraulic pump to the hydraulic actuator for operating the work machine (work machine).

  Accordingly, an object of the present invention is to provide a hydraulic circuit control system capable of reducing a pressure loss generated by pressure oil discharged from an actuator for a work machine.

  In the hydraulic circuit control system according to the present invention, the hydraulic circuit includes a plurality of actuators, a plurality of directional switching valves that switch operating directions of the plurality of actuators, and a plurality of actuators for operating each of the plurality of actuators. An operation lever, a plurality of pipes connecting each of the plurality of actuators and the plurality of directional control valves, and a pair or each pair of actuators of the plurality of actuators out of the plurality of pipes At least one switching valve that switches between a communication state and a cutoff state between a pair or each pair of pipes connected to each other, and the control device includes the pair or each pair of the plurality of operation levers. Based on the detection signal of each of the pair or each pair of operation levers corresponding to The presence or absence of a switching instruction for one switching valve is determined, and when there is a switching instruction for the at least one switching valve, the pair or each pair of pipes is switched from a shut-off state to a communication state by the at least one switching valve. It is characterized by that.

  According to the hydraulic circuit control system of the present invention, there is an operation on the first actuator (one actuator) and there is no operation on the second actuator (the other actuator) paired therewith, or the operation of the second actuator is When there is an operation that is not significantly affected by fluctuations in the hydraulic pressure of the corresponding pipeline, the first pipeline (one pipeline) corresponding to the first actuator and the second pipeline (others) corresponding to the second actuator Can be switched from the shut-off state to the communication state by at least one switching valve. Thereby, a part of the pressure oil sent from the first actuator to the first pipeline is sent to the second pipeline, and when there are two or more switching valves, the partial hydraulic pressure is again returned to the first pipeline. Therefore, the pressure loss in the first pipeline is reduced.

  In the hydraulic circuit control system of the present invention, in at least one of the pair or each pair of pipes, the at least one switching valve is closer to the actuator than to the direction switching valve. Is preferably provided.

  According to the hydraulic circuit control system having the above configuration, the distance between the switching valve and the first actuator in at least one of the pair of pipes (the first pipe and the second pipe) (the first pipe) is set. Shortening is attempted. For this reason, when the pressure oil is sent out from the first actuator, a part of the pressure oil easily flows into the second pipe by the amount corresponding to the shortening of the distance, so the first pipe (particularly upstream from the switching valve). Is further reduced in pressure loss.

  In the hydraulic circuit control system of the present invention, the hydraulic circuit includes a sub-pipe that communicates with the tank from an intermediate position of the directional switching valve and the switching valve in one of the pair or each pair of pipes; A sub-switching valve disposed in the sub-pipe and switching the communication state and the shut-off state of the one pipe and the tank, and the control device detects each detection signal of the pair or each pair of operation levers. And determining whether or not there is a switching instruction for the sub switching valve in addition to the at least one switching valve, and if there is a switching instruction for the sub switching valve in addition to the at least one switching valve, the at least one switching valve The pair of pipes or each pair of pipes are switched from the shut-off state to the communication state by the switching valve, and the one pipe line and the tank are connected from the shut-off state to the communication state by the sub-switch valve It is preferable to switch.

  According to the hydraulic circuit control system having the above configuration, a part of the pressure oil sent from the first actuator to the first pipeline is added to the second pipeline (one of the pair of pipelines) by the switching valve. Thus, it can be returned to the tank via the secondary pipe. For this reason, when pressure oil is sent out from the 1st actuator, the fall of the pressure loss which arises in the 1st pipe line (especially the upstream side rather than the change-over valve) is attained.

  In the hydraulic circuit control system according to the present invention, the control device may include the pair of or each pair of pipe lines in addition to the at least one switching valve based on the detection signals of the pair or each pair of operation levers. The presence / absence of a switching instruction for the direction switching valve on one pipe is determined, and when there is a switching instruction for the at least one switching valve and the direction switching valve on the one pipe, the at least one switching valve It is preferable that the pair or each pair of pipes is switched from the shut-off state to the communication state, and the one pipe line and the tank are switched from the shut-off state to the communication state by the direction switching valve.

  According to the hydraulic circuit control system having the configuration, a part of the pressure oil sent from the first actuator to the first pipe is sent to the second pipe (one of the pair of pipes) by the switching valve. Further, it can be returned to the tank via the second direction switching valve. For this reason, when pressure oil is sent out from the 1st actuator, the fall of the pressure loss which arises in the 1st pipe line (especially the upstream side rather than the change-over valve) is attained.

  In the hydraulic circuit control system of the present invention, it is preferable that each pair of pipes has a common pipe.

  According to the hydraulic circuit control system having the above configuration, the first actuator (one actuator) is operated, and the second actuator (the other actuator that forms a first pair with the one actuator) is not operated. The first pipe (one pipe) corresponding to the first actuator and the second pipe (other pipe) corresponding to the second actuator are switched from the shut-off state to the communication state by the first switching valve. . Similarly, when there is an operation on the first actuator (one actuator) and there is no operation on the third actuator (another actuator that forms a second pair with the one actuator), the first actuator corresponding to the first actuator is used. One pipe line (one pipe line) and a third pipe line (or another pipe line) corresponding to the third actuator are switched from the shut-off state to the communication state by the second switching valve (or the first switching valve). . Thereby, a part of the pressure oil sent from the first actuator to the first pipeline is sent to the third pipeline in addition to the second pipeline, so that the pressure loss in the first pipeline can be further reduced.

BRIEF DESCRIPTION OF THE DRAWINGS Configuration explanatory drawing of the hydraulic circuit control system as 1st Embodiment of this invention. Explanatory drawing regarding the control method of the hydraulic circuit as 1st Embodiment of this invention. Functional explanatory drawing of the hydraulic circuit control system as a 1st embodiment of the present invention. The structure explanatory view of the hydraulic circuit control system as a 2nd embodiment of the present invention. Explanatory drawing regarding the control method of the hydraulic circuit as 2nd Embodiment of this invention. Functional explanatory drawing of the hydraulic circuit control system as a 2nd embodiment of the present invention. The structure explanatory view of the hydraulic circuit control system as a 3rd embodiment of the present invention. Explanatory drawing regarding the control method of the hydraulic circuit as 3rd Embodiment of this invention. The 1st function explanatory view of the hydraulic circuit control system as a 3rd embodiment of the present invention. The 2nd function explanatory view of the hydraulic circuit control system as a 3rd embodiment of the present invention. FIG. 9 is a configuration explanatory diagram of a hydraulic circuit control system as a fourth embodiment of the present invention. Explanatory drawing regarding the control method of the hydraulic circuit as 4th Embodiment of this invention. Functional explanatory drawing of the hydraulic circuit control system as a 4th embodiment of the present invention.

(First embodiment)
(Constitution)
The hydraulic circuit control system according to the first embodiment of the present invention shown in FIG. 1A includes a hydraulic circuit and a control device 50. The hydraulic circuit includes a first actuator 12, a second actuator 22, a first direction switching valve 14 that switches an operating direction of the first actuator 12, a second direction switching valve 24 that switches an operating direction of the second actuator 22, A first pipe connecting the first operating lever 142 for operating the first actuator 12, the second operating lever 242 for operating the second actuator 22, and the first actuator 12 and the first direction switching valve 14. L11, L12, second pipes L21, L22 connecting the second actuator 22 and the second direction switching valve 24, and a pair of pipes L12, L22 connected to the pair of actuators 12, 22, respectively. And a switching valve 41 (first switching valve) that switches between the communication state and the cutoff state between each other. The hydraulic circuit includes a sub-pipe L10 (first sub-pipe) that branches from the second pipe L22 and communicates with the tank T at an intermediate position between the switching valve 41 and the second direction switching valve 24, and a sub-pipe. A return-only valve 410 (first sub-switching valve) and a solenoid switching valve 412 (first electromagnetic switching valve) which are arranged at L10 and switch between the communication state and the shut-off state of the second pipe L22 and the tank T; ing.

  The 1st actuator 12 is comprised by the hydraulic cylinder for operating a 1st working machine (for example, crusher). The 2nd actuator 22 is comprised by the hydraulic cylinder for operating a 2nd working machine (for example, bucket).

  The first direction switching valve 14 is controlled to three positions (a left position, a center position, and a right position) by controlling the supply mode of the pressure oil delivered from the hydraulic pump 40 by the first operation lever 142. By controlling the first direction switching valve 14 to the left position, the pressure oil sent from the first hydraulic pump 16 flows into the first actuator 12 from the first port through one first pipe L11, The pressure oil flowing out from the second port of one actuator 12 flows to the tank T through the other first pipe L12. By controlling the first direction switching valve 14 to the right position, the pressure oil sent from the first hydraulic pump 16 flows into the first actuator 12 from the second port through the other first pipe L12, The pressure oil flowing out from the first port of one actuator 12 flows into the tank T through one first pipe L11. By controlling the first direction switching valve 14 to the center position, the flow of the pressure oil in the first pipes L11 and L12 is blocked.

  The detection signal of the hydraulic sensor S11 is input to the control device 50 as a detection signal of the first operating lever 142 for controlling the first direction switching valve 14 to the left position and operating the first actuator 12 in the first direction. The The detection signal of the hydraulic sensor S12 is input to the control device 50 as a detection signal of the first operating lever 142 for controlling the first direction switching valve 14 to the right position and operating the first actuator 12 in the second direction. The

  The second direction switching valve 24 is controlled to three positions (a left position, a center position, and a right position) by controlling the supply mode of the pressure oil delivered from the hydraulic pump 40 by the second operation lever 242. By controlling the second directional control valve 24 to the right position, the pressure oil sent from the second hydraulic pump 26 flows into the second actuator 22 from the first port through one second pipe L21, 2 The pressure oil flowing out from the second port of the actuator 22 flows to the tank T through the other second pipe L22. By controlling the second direction switching valve 24 to the left position, the pressure oil sent from the second hydraulic pump 26 flows into the second actuator 22 from the second port through the other second pipe L22, 2 The pressure oil flowing out from the first port of the actuator 22 flows into the tank T through one second pipe L21. By controlling the second direction switching valve 24 to the center position, the flow of the pressure oil in the second pipes L21 and L22 is blocked.

  The detection signal of the hydraulic sensor S21 is input to the control device 50 as a detection signal of the second operation lever 242 for controlling the second direction switching valve 24 to the right position and operating the second actuator 22 in the first direction. The The detection signal of the hydraulic sensor S22 is input to the control device 50 as a detection signal of the second operating lever 242 for controlling the second direction switching valve 24 to the left position and operating the second actuator 22 in the second direction. The

  The switching valve 41 is controlled to two positions (left side position and right side position) by controlling the supply mode of the pressure oil delivered from the hydraulic pump 40 by the electromagnetic switching valve 412. When the switching valve 41 is controlled to the right side position, the first pipe line L12 and the second pipe line L22 are controlled to be in a communicating state, while the switching valve 41 is controlled to the left side position, so that the first pipe line is controlled. L12 and the 2nd pipe line L22 are controlled by the interruption | blocking state.

  The switching valve 41 is disposed closer to the first actuator 12 than to the first direction switching valve 14 in the first pipeline L12. Similarly, the switching valve 41 is disposed closer to the second actuator 22 than to the second direction switching valve 24 in the second pipeline L22. The switching valve 41 is more preferably disposed closer to the first actuator 12 in the second pipeline L22 than to the connection location with the sub pipeline L10.

  The return dedicated valve 410 is controlled to two positions (a left position and a right position) by controlling the supply mode of the pressure oil delivered from the hydraulic pump 40 by the electromagnetic switching valve 412. By controlling the return dedicated valve 410 to the right position, the pressure oil flows from the other second pipe L22 to the tank T through the sub pipe L10. By controlling the return-only valve 410 to the left side position, the flow of pressure oil in the sub-line L10 is blocked.

  The control device 50 is configured by a computer (comprising an arithmetic processing device (CPU (multiprocessor, etc.)), a storage device (memory such as ROM, RAM, etc.), an I / O circuit, etc.). The control device 50 is designed or programmed to determine whether there is a switching instruction for the switching valve 41 and the return dedicated valve 410 (sub switching valve) based on the detection signals of the first operating lever 142 and the second operating lever 242, respectively. (It has a function as a determination device). When there is an instruction to switch the switching valve 41 and the return dedicated valve 410, the control device 50 gives a command to switch the electromagnetic switching valve 412 to the right position from the control device 50, and controls the switching valve 41 with the pressure oil delivered from the hydraulic pump 40. Designed or programmed to switch the first pipe L12 and the second pipe L22 from the cut-off state to the communication state by displacing from the left side position to the right side position (having a function as a valve switching control device) )

(function)
The first pipe L12 and the second pipe L22 connected to the pair of actuators 12 and 22 by the switching valve 41 are controlled to be shut off, and the second pipe L22 and the second pipe L22 by the return dedicated valve 410 are controlled. A function of the control device 50 in a state where the tank T is controlled to be in a shut-off state will be described. In this state, the detection signal PI1 of the first operating lever 142, which is represented by the output signal of the hydraulic sensor S11 and operates the first actuator 12 in the first direction (for example, the crusher opening direction), has the first reference value Pa. It is determined whether or not it exceeds (FIG. 1B / STEP 101).

  When the determination result is affirmative (FIG. 1B / STEP 101... YES), the second actuator 22 represented by the output signals of the hydraulic sensors S21 and S22 is moved in the first direction (for example, the excavation direction of the bucket) or the second It is determined whether or not the detection signal PI2 of the second operating lever 242 operated in the direction (for example, the bucket discharging direction) is less than the second reference value Pb (FIG. 1B / STEP102).

  If the determination result is affirmative (FIG. 1B / STEP 102... YES), the controller 50 instructs the electromagnetic switching valve 412 to switch the electromagnetic switching valve 412 as shown in FIG. The first pipe L12 and the second pipe L22 are switched from the shut-off state to the communication state, and the second pipe L22 and the tank T are switched from the shut-off state to the communication state by the return dedicated valve 410 (FIG. 1B / STEP 104). ).

  If any of the above determination results is negative (FIG. 1B / STEP101... NO, STEP102... NO), the processing from FIG. 1B / STEP101 onward is repeated.

(effect)
According to the hydraulic circuit control system as the first embodiment of the present invention, there is an operation on the first actuator 12 (FIG. 1B / STEP 101... YES), and there is no operation on the second actuator 22 paired therewith. (FIG. 1B / STEP102... YES), the first pipe L12 and the second pipe L22 are switched from the shut-off state to the communication state by the switching valve 41 (see FIG. 2). The second pipe L22 is blocked on the upstream side and the downstream side of the switching valve 41. Further, the second pipe L22 and the tank T are switched from the shut-off state to the communication state by the return dedicated valve 410. Accordingly, the pressure oil sent from the second port of the first actuator 12 to the first pipe L12 is sent to the second pipe L22, and further sent from the second pipe L22 to the tank T through the sub pipe L10. Therefore, the pressure loss in the first pipeline L12 is reduced.

(Second Embodiment)
(Constitution)
In the hydraulic circuit control system according to the second embodiment of the present invention shown in FIG. 3A, the auxiliary pipe L10 and the return dedicated valve 410 are omitted, and the alternative auxiliary pipe L10 ′ and the unloading valve 410 ′ are the first. A branch line L2 connecting the two-way switching valve 24 and the second hydraulic pump 26 is branched to communicate with the tank T. In other respects, the hydraulic circuit of the second embodiment has substantially the same configuration as the hydraulic circuit of the first embodiment, so the same reference numerals are used and description thereof is omitted.

(function)
The control device 50 in a state where the first pipe L12 and the second pipe L22 are controlled to be shut off by the switching valve 41, and the pipe L2 and the tank T are controlled to be shut off by the unload valve 410 ′. The function will be described. In this state, the detection signal PI1 of the first operating lever 142, which is represented by the output signal of the hydraulic sensor S11 and operates the first actuator 12 in the first direction (for example, the crusher opening direction), has the first reference value Pa. It is determined whether or not it exceeds (FIG. 3B / STEP 201).

  If the determination result is affirmative (FIG. 3B / STEP 201... YES), the second actuator 22 represented by the output signals of the hydraulic sensors S21 and S22 is moved in the first direction (for example, the excavation direction of the bucket) or the second It is determined whether or not the detection signal PI2 of the second operating lever 242 that is actuated in the direction (for example, the bucket discharging direction) is less than the second reference value Pb (FIG. 3B / STEP 202).

  When the determination result is affirmative (FIG. 3B / STEP 202... YES), as shown in FIG. 4, the first conduit L12 and the second conduit L22 are changed from the shut-off state to the communication state by the switching valve 41. The line L2 and the tank T are switched from the shut-off state to the communication state by the unload valve 410 ′, and the second direction switching valve 24 is controlled to the right position (FIG. 3B / STEP 204).

  If any of the above determination results is negative (FIG. 3B / STEP 201... NO, STEP 202... NO), the processes after FIG. 3B / STEP 201 are repeated.

(effect)
According to the hydraulic circuit control system as the second embodiment of the present invention, there is an operation on the first actuator 12 (FIG. 3B / STEP 201... YES), and there is no operation on the second actuator 22 paired therewith, or When there is an operation whose operation is not significantly affected by the hydraulic pressure fluctuation of the corresponding pipelines L21 and L22 (FIG. 3B / STEP202... YES), the first pipeline L12 and the second pipeline L22 are blocked by the switching valve 41. To the communication state (see FIG. 4). The second pipe L22 is blocked on the upstream side and the downstream side of the switching valve 41. Further, the second direction switching valve 24 is controlled to the right position. As a result, the pressure oil sent from the second port of the first actuator 12 to the first pipe L12 is sent to the second pipe L22 and sent to the tank T through the second direction switching valve 24, so that the first Reduction of pressure loss in the pipe line L12 is achieved.

  Further, when the line L2 and the tank T are switched from the shut-off state to the communication state by the unload valve 410 ′, the hydraulic pressure sent out from the second hydraulic pump 26 to one of the second pipes L12 is increased. The increase in hydraulic pressure in the second pipe L22 is suppressed. For this reason, the pressure loss in the first pipeline L12 can be reduced as described above while allowing the second actuator 22 to operate in the first direction.

(Third embodiment)
(Constitution)
In the hydraulic circuit control system according to the third embodiment of the present invention shown in FIG. 5A, the auxiliary pipe L10 and the return dedicated valve 410 are omitted, and the second switching valve 42 is provided. Similarly to the first switching valve 41, the second switching valve 42 is controlled to two positions (left side position and right side position) by controlling the supply mode of the pressure oil delivered from the hydraulic pump 40 by the electromagnetic switching valve 412. Is done. By controlling the second switching valve 42 to the right side position, the first pipe line L12 and the second pipe line L22 connected to the pair of actuators 12 and 22 are controlled to be in a communication state, By controlling the second switching valve 42 to the left side position, the first pipe line L12 and the second pipe line L22 are controlled to be cut off.

  The second switching valve 42 is disposed closer to the first actuator 12 than to the first direction switching valve 14 in the first pipeline L12. Similarly, the second switching valve 42 is disposed closer to the second actuator 22 than to the second direction switching valve 24 in the second pipeline L22. The distance between the first switching valve 41 and the first actuator 12 (or the second actuator 22) may be shorter than the distance between the first switching valve 41 and the second switching valve. The distance between the first switching valve 41 and the first actuator 12 (or the second actuator 22) may be shorter than the distance between the second switching valve 42 and the second directional switching valve 24.

  In other respects, since the hydraulic circuit of the third embodiment has substantially the same configuration as the hydraulic circuit of the first embodiment, the same reference numerals are used and description thereof is omitted.

(function)
The function of the control device 50 in a state where the first pipeline L12 and the second pipeline L22 are controlled to be shut off by the first switching valve 41 and the second switching valve 42 will be described. In this state, the detection signal PI1 of the first operating lever 142, which is represented by the output signal of the hydraulic sensor S11 and operates the first actuator 12 in the first direction (for example, the crusher opening direction), has the first reference value Pa. It is determined whether or not it exceeds (FIG. 5B / STEP 301).

  When the determination result is affirmative (FIG. 5B / STEP 301... YES), the second actuator 22 represented by the output signals of the hydraulic sensors S21 and S22 is moved in the first direction (for example, the excavation direction of the bucket) or the second It is determined whether or not the detection signal PI2 of the second operating lever 242 operated in the direction (for example, the bucket discharging direction) is less than the second reference value Pb (FIG. 5B / STEP 302).

  If the determination result is affirmative (FIG. 5B / STEP 302... YES), as shown in FIG. 6, the first line L12 and the second line are respectively set by the first switching valve 41 and the second switching valve 42. The pipe L22 is switched from the shut-off state to the communication state, and the first direction switching valve 14 is controlled to the left position (FIG. 5B / STEP 304). The second pipeline L22 is blocked at the upstream side and the downstream side of the first switching valve 41, and is blocked at the upstream side and the downstream side of the second switching valve 42.

  If any of the above determination results is negative (FIG. 5B / STEP301... NO, STEP302... NO), the processing from FIG. 5B / STEP301 onward is repeated.

(effect)
According to the hydraulic circuit control system as the third embodiment of the present invention, there is an operation on the first actuator 12 (FIG. 5B / STEP 301... YES), and there is no operation on the second actuator 22 paired therewith. In the equivalent case (FIG. 5B / STEP 302... YES), the first pipe L12 and the second pipe L22 are switched from the shut-off state to the communication state by the first switching valve 41 and the second switching valve 42 (see FIG. 6). . Further, the first direction switching valve 14 is controlled to the left position. As a result, a part of the pressure oil sent from the second port of the first actuator 12 to the first pipe L12 is sent to the second pipe L22, and after returning to the first pipe L12 again, the first direction Since it is sent to the tank T through the switching valve 14, the pressure loss in the said 1st pipe line L12 is reduced.

(Other functions of the third embodiment)
In the hydraulic circuit control system as the third embodiment of the present invention, a first operation for operating the first actuator 12 in the second direction (for example, the closing direction of the crusher) represented by the output signal of the hydraulic sensor S12. The detection signal PI2 of the second operating lever 242 that causes the detection signal PI1 of the lever 142 to exceed the first reference value Pa and operates the second actuator 22 in the first direction (for example, the excavation direction of the bucket) or the second direction. Is less than the second reference value Pb, as shown in FIG. 7, the first pipeline L12 and the second pipeline L22 are disconnected from each other by the first switching valve 41 and the second switching valve 42, respectively. The communication state may be switched, and the first direction switching valve 14 may be controlled to the right position instead of the left position (FIG. 5B / STEP 301... YES → STE See 302 ‥ YES → STEP304).

  As a result, a part of the pressure oil sent from the first hydraulic pump 16 to the first pipeline L12 is sent to the second pipeline L22, and after returning to the first pipeline L12 again, the second of the first actuator 12 Therefore, the pressure loss in the first pipe L12 can be reduced.

(Fourth embodiment)
(Constitution)
The hydraulic circuit control system according to the fourth embodiment of the present invention shown in FIG. 8A includes a third actuator 32, a third direction switching valve 34 for switching the operating direction of the third actuator 32, and a second actuator. A third operating lever 342 for operating the three actuators 32, third pipes L31 and L32 connecting the third actuator 32 and the third direction switching valve 34, and a communication state between the pair of pipes L12 and L32. And a second switching valve 42 for switching the shut-off state. The hydraulic circuit branches from the third pipe L32 at an intermediate position between the second switching valve 42 and the third directional switching valve 34 and communicates with the tank T and the second sub pipe L20. And a second return dedicated valve 420 (second auxiliary switching valve) and an electromagnetic switching valve 422 (second electromagnetic switching valve) for switching the communication state and cutoff state of the third pipe L32 and the tank T. I have.

  The third actuator 32 is configured by a hydraulic cylinder for operating a third work machine (for example, an arm to which the first work machine or the second work machine is attached).

  The third direction switching valve 34 is controlled to three positions (a left position, a center position, and a right position) by controlling the supply mode of the pressure oil delivered from the hydraulic pump 40 by the third operation lever 342. By controlling the third direction switching valve 34 to the right side position, the pressure oil sent from the first hydraulic pump 16 flows into the third actuator 32 from the first port through one third pipe L31, The pressure oil flowing out from the second port of the three actuators 32 flows into the tank T through the other third pipe L32. When the third direction switching valve 34 is controlled to the left position, the pressure oil sent from the first hydraulic pump 16 flows into the third actuator 32 from the second port through the other third pipe L32, The pressure oil flowing out from the first port of the three actuators 32 flows to the tank T through one third pipe L31. By controlling the third direction switching valve 34 to the center position, the flow of the pressure oil in the third pipelines L31 and L32 is blocked.

  The detection signal of the hydraulic sensor S31 is input to the control device 50 as a detection signal of the third operation lever 342 for controlling the third direction switching valve 34 to the right position and operating the first actuator 12 in the first direction. The The detection signal of the hydraulic sensor S32 is input to the control device 50 as a detection signal of the third operating lever 342 for controlling the third direction switching valve 34 to the left position and operating the third actuator 32 in the second direction. The

  The second switching valve 42 is controlled to two positions (left side position and right side position) by controlling the supply mode of the pressure oil delivered from the hydraulic pump 40 by the electromagnetic switching valve 422. By controlling the second switching valve 42 to the right side position, the first pipe line L12 and the third pipe line L32 are controlled to be in a communicating state, while the second switching valve 42 is controlled to the left side position. The 1st pipe line L12 and the 3rd pipe line L32 are controlled by the interruption | blocking state.

  The second return valve 420 is controlled to two positions (a left position and a right position) by controlling the supply mode of the pressure oil delivered from the hydraulic pump 40 by the electromagnetic switching valve 422. By controlling the second return valve 420 to the right position, the pressure oil flows from the other third pipe L32 to the tank T through the second sub pipe L20. By controlling the second dedicated return valve 420 to the left side position, the flow of pressure oil in the second sub-line L20 is blocked.

  In other respects, since the hydraulic circuit of the fourth embodiment has substantially the same configuration as the hydraulic circuit of the first embodiment, the same reference numerals are used and description thereof is omitted.

(function)
The first and second pipes L12 and L22 connected to each of the pair of actuators 12 and 22 by the first switching valve 41 are controlled to be shut off, and the second switching valve 42 sets the other pair. The function of the control device 50 in a state in which the first pipe line L12 and the third pipe line L32 connected to the actuators 12 and 32 are controlled to be cut off will be described. In this state, the detection signal PI1 of the first operating lever 142, which is represented by the output signal of the hydraulic sensor S11 and operates the first actuator 12 in the first direction (for example, the crusher opening direction), has the first reference value Pa. It is determined whether or not it exceeds (FIG. 8B / STEP 401).

  When the determination result is affirmative (FIG. 8B / STEP 401... YES), the second actuator 22 represented by the output signals of the hydraulic sensors S21 and S22 is moved in the first direction (for example, the excavation direction of the bucket) or the second It is determined whether or not the detection signal PI2 of the second operating lever 242 that is actuated in the direction (for example, the bucket discharging direction) is less than the second reference value Pb (FIG. 8B / STEP 402).

  When the determination result is affirmative (FIG. 8B / STEP402... YES), as shown in FIG. 9, the first switching valve 41 causes the first pipeline L12 and the second pipeline L22 to communicate from the blocked state. In addition, the second conduit L22 and the tank T are switched from the shut-off state to the communication state by the first return valve 410 (FIG. 8B / STEP 403). The second pipeline L22 is blocked on the upstream side and the downstream side of the first switching valve 41.

  If the determination result is negative (FIG. 8B / STEP402... NO), the first switching valve 41 maintains the first pipeline L12 and the second pipeline L22 in a shut-off state, and the first return valve 410 Thus, the second pipe line L22 and the tank T are maintained in the shut-off state (FIG. 8B / STEP 404).

  Subsequently, a third operating lever that operates the third actuator 32 in the first direction (for example, the pulling direction of the arm) or the second direction (for example, the pressing direction of the arm) represented by the output signals of the hydraulic sensors S31 and S32. It is determined whether or not the detection signal PI3 of 342 is less than the third reference value Pc (FIG. 8B / STEP 405).

  When the determination result is affirmative (FIG. 8B / STEP405... YES), the second switching valve 42 switches the first pipeline L12 and the third pipeline L32 from the shut-off state to the communication state, and the second return. The third pipe L32 and the tank T are switched from the shut-off state to the communication state by the dedicated valve 420 (FIG. 8B / STEP 406). The third pipeline L32 is blocked on the upstream side and the downstream side of the second switching valve 42. Further, the first direction switching valve 14 is controlled to the left position (same as above).

  When the determination result is negative (FIG. 8B / STEP405... NO), the second switching valve 42 keeps the first pipeline L12 and the third pipeline L32 in the shut-off state, and the second return dedicated valve 420. Thus, the third pipe L32 and the tank T are maintained in the shut-off state (FIG. 8B / STEP407). Thereafter, the processing after FIG. 8B / STEP 401 is repeated.

(effect)
According to the hydraulic circuit control system as the fourth embodiment of the present invention, there is an operation on the first actuator 12 (FIG. 8B / STEP 401... YES), and there is no operation on the second actuator 22 paired therewith. In the equivalent case (FIG. 8B / STEP 402... YES), the first switching valve 41 switches the first pipeline L12 and the second pipeline L22 from the shut-off state to the communication state, and the first return dedicated valve 410 The pipe L22 and the tank T are switched from the shut-off state to the communication state (see FIG. 9). Further, when the third actuator 32 is not operated or equivalent (FIG. 8B / STEP405... YES), the second switching valve 42 switches the first pipeline L12 and the third pipeline L32 from the shut-off state to the communication state. In addition, the second return valve 420 switches the third pipe L32 and the tank T from the shut-off state to the communication state (same as above). The first direction switching valve 14 is controlled to the left position (same as above).

  As a result, the first part, which is a part of the pressure oil sent from the second port of the first actuator 12 to the first pipe L12, is sent to the second pipe L22, and a part of the first part is further sent. It is sent to the tank T through the first sub pipe L10. In addition, a second part, which is a part excluding the first part of the pressure oil sent from the second port of the first actuator 12 to the first pipe L12, is sent to the third pipe L32, and further the second part Is sent to the tank T through the second auxiliary pipe L20. The remaining portion excluding the first portion and the second portion of the pressure oil sent from the second port of the first actuator 12 to the first pipe L12 is sent to the tank T through the first direction switching valve 14. Thereby, reduction of the pressure loss in the said 1st pipe line L12 is achieved.

(Other embodiments of the present invention)
The sub pipe L10 and the return dedicated valve 410 may be omitted from the hydraulic circuit of the first embodiment (see FIG. 1A). The auxiliary pipe L10 ′ and the unload valve 410 ′ of the hydraulic circuit of the second embodiment may be added to the hydraulic circuit of the first embodiment (see FIG. 3A). Even if the operations of the first switching valve 41 and the second switching valve 42 in the hydraulic circuit of the third embodiment are controlled by separate electromagnetic switching valves 412 and 422, respectively, as in the hydraulic circuit of the fourth embodiment. Good (see FIG. 5A and FIG. 8A).

  Each operation of the first switching valve 41 and the second switching valve 42 in the hydraulic circuit of the fourth embodiment may be controlled by a common electromagnetic switching valve 412 as in the hydraulic circuit of the third embodiment (FIG. 5A). And see FIG. 8A). The operation of the third actuator 32 in the hydraulic circuit of the fourth embodiment may be controlled by pressure oil delivered from a third hydraulic pump separate from the first hydraulic pump 16 (see FIG. 8A). The first sub pipe L10 and the first return dedicated valve 410 may be omitted from the hydraulic circuit of the fourth embodiment, and the second sub pipe L20 and the second return dedicated valve 420 may be omitted as an alternative or in addition. (See FIG. 8A).

  There may be four or more actuators and corresponding pipe lines. For example, when there are four pipe lines, the first pipe line and the second pipe line form a first pair, and the third pipe line and the fourth pipe line are independent of the first pair. You may make a pair. When there are four pipe lines, the first pipe line and the second pipe line may form a first pair, and the first pipe line and the fourth pipe line may form a second pair. Further, the second pipe and the third pipe may form a third pair. In either case, a switching valve that switches between the communication state and the shut-off state between each pair of pipe lines is provided, and the operation of the valve is appropriately controlled, thereby further reducing the pressure loss of the pipe lines.

DESCRIPTION OF SYMBOLS 12 ... 1st actuator, 14 ... 1st direction switching valve, 142 ... 1st operation lever, 16 ... 1st hydraulic pump, 22 ... 2nd actuator, 24 ... 2nd direction switching valve, 242 ... 2nd operation lever, 26 2nd hydraulic pump, 32 3rd actuator, 34 3rd direction switching valve, 342 3rd operation lever, 36 3rd hydraulic pump, 40 hydraulic pump, 41 switching valve (first switching valve), 42 ... 2nd switching valve, 410 ... Return-only valve (first auxiliary switching valve), 412 ... Electromagnetic switching valve (first electromagnetic switching valve), 420 ... 2nd return-only valve (second auxiliary switching valve), 422 ... Second electromagnetic switching valve, L10 ··· sub pipe (first sub pipe), L11, L12 ··· first pipe, L20 ··· second sub pipe, L21 and L22 ··· second pipe, L31 and L32 ··· 3 pipelines.

Claims (5)

A hydraulic circuit control system comprising a hydraulic circuit and a control device,
The hydraulic circuit is
Multiple actuators;
A plurality of directional control valves for switching the operating directions of the plurality of actuators;
A plurality of operating levers for operating each of the plurality of actuators;
A plurality of conduits connecting each of the plurality of actuators and each of the plurality of directional control valves;
At least one switching valve for switching a communication state and a blocking state between a pair or each pair of pipes connected to each of a pair or each pair of actuators of the plurality of actuators among the plurality of pipes. And comprising
The control device determines whether or not there is a switching instruction for the at least one switching valve based on a detection signal of each of the pair or each pair of operation levers corresponding to the pair or each pair of pipes among the plurality of operation levers. Judgment,
The hydraulic circuit control system according to claim 1, wherein when there is an instruction to switch the at least one switching valve, the pair or each pair of pipes is switched from a shut-off state to a communication state by the at least one switching valve. The hydraulic circuit control system according to claim 1, wherein
In one or both of the pair or each pair of pipes, the at least one switching valve is provided at a location closer to the actuator than to the direction switching valve. Hydraulic circuit control system to do. The hydraulic circuit control system according to claim 1, wherein
The hydraulic circuit is connected to the tank from an intermediate position of the direction switching valve and the switching valve of one of the pair or each pair of pipes; and
A sub-switching valve disposed in the sub-pipe and switching the communication state and the shut-off state of the one pipe and the tank;
The control device determines whether or not there is a switching instruction for the sub switching valve in addition to the at least one switching valve based on the detection signals of the pair or each pair of operation levers,
When there is an instruction to switch the sub switching valve in addition to the at least one switching valve, the at least one switching valve switches the pair or each pair of pipes from a shut-off state to a communication state, and A hydraulic circuit control system, wherein the one pipe line and the tank are switched from a shut-off state to a communication state by a switching valve. The hydraulic circuit control system according to claim 1, wherein
The control device, in addition to the at least one switching valve based on the detection signals of the pair or each pair of operation levers, the directional switching valve of one of the pair or each pair of pipes The presence or absence of switching instructions,
When there is an instruction to switch the direction switching valve of the at least one switching valve and the one conduit, the pair or each pair of conduits is switched from a shut-off state to a communication state by the at least one switching valve, The hydraulic circuit control system is characterized in that the one conduit and the tank are switched from the shut-off state to the communication state by the direction switching valve. The hydraulic circuit control system according to claim 1, wherein
The hydraulic circuit control system, wherein each pair of pipes has a common pipe.