JP2010101095A - Hydraulic control device for working machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic control device for a working machine, capable of ensuring the required flow rate of circuit of a high load pressure actuator when performing a composite operation, improving energy efficiency, and simplifying a valve configuration. <P>SOLUTION: This hydraulic control device for the working machine is constituted by providing a selector valve 29 being switched and controlled with the control device 36 and a pilot pressure control valve 37 in a discharge pipe passage of hydraulic pumps 27, 28, and providing both of first priority valve 30 and second priority valve 31 being flow rate control valves with pressure compensation function on the downstream side of the selector valve 29. When the composite operation is performed, the oil discharged from the pumps is supplied into right and left running motors 11R, 11L or a crushing cylinder 12 through the selector valve 29 and the first or second priority valve 30 or 31 with priority while controlling the flow rate with the pressure compensation function, and a surplus of oil is supplied into the other hydraulic actuators. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a hydraulic control device for a working machine such as a hydraulic excavator and a crusher configured by diverting the hydraulic excavator.

  As shown in FIG. 4, the excavator has an upper swing body 2 mounted on a crawler-type lower traveling body 1 so as to be rotatable about a vertical axis. The upper swing body 2 has a boom 3, an arm 4, a bucket 5, And a work attachment A composed of boom, arm, and bucket cylinders (hydraulic cylinders) 6 to 8 as hydraulic actuators for operating them, and excavation and loading work are performed.

  Further, as other hydraulic actuators, left and right traveling motors that drive the lower traveling body 1 and a swing motor (none of which is shown) that swings the upper swing body 2 are provided.

  On the other hand, this hydraulic excavator may be diverted to other work machines, for example, a crusher as shown in FIG.

  In this case, a crushing device 9 as an option for crushing a concrete structure or the like by opening and closing by a crushing cylinder (optional actuator) (not shown) is attached to the tip of the work attachment A instead of the bucket 5. Accordingly, there are seven hydraulic actuators including a crushing cylinder.

  This hydraulic actuator group and a control valve group which is a hydraulic pilot switching valve for individually controlling these hydraulic actuator groups are usually divided into two groups, and both groups are driven by separate pumps.

  For example, the arm cylinder 7, the turning motor, the left traveling motor, the crushing cylinder, and a control valve which is a hydraulic pilot switching valve for individually controlling them belong to the first group and are connected in parallel to the first hydraulic pump.

  On the other hand, the boom cylinder 6, the bucket cylinder 8, the right traveling motor, and a control valve which is a hydraulic pilot switching valve for individually controlling them belong to the second group and are connected in parallel to the second hydraulic pump.

  Normally, travel straight-advancing valves are provided in the discharge pipes of both hydraulic pumps, and when the left and right travel motors are operated simultaneously, the travel straight-advancing valves cause the oil discharged from both hydraulic pumps to merge with both travel motors. Distributed by quantity. This is configured to ensure straightness.

  According to such a so-called parallel circuit, the actuator flow rate on the high load pressure side is insufficient when the load pressures (operating pressures) of the simultaneously operating hydraulic actuators are different during the combined operation of simultaneously operating a plurality of hydraulic actuators in the same group. There is a problem of doing.

  For example, when the swing motor and the arm cylinder 7 are operated simultaneously, the circuit flow rate of the swing motor having a high load pressure is insufficient, and the swing speed becomes slow. Further, when the crushing cylinder and other actuators are operated simultaneously, the circuit flow rate of the crushing cylinder on the high load pressure side is insufficient.

  As a means for solving this problem, for example, a technique described in Patent Document 1 is known.

In this known technique, the circuit flow rate of a hydraulic actuator other than the hydraulic actuator having the highest load pressure (hereinafter referred to as a specific hydraulic actuator) among all the hydraulic actuators is throttled by a throttle valve (compensator valve), so that the required circuit flow rate of the specific hydraulic actuator is obtained. The structure which secures is taken.
JP 2003-301803 A

  However, according to this known technique, the pressure loss due to the throttle is large and the energy efficiency (fuel consumption) is deteriorated. In addition, the throttle valve is provided for all hydraulic actuators other than the specific hydraulic actuator. Become.

  Therefore, the present invention can secure the required circuit flow rate of the high load pressure actuator during combined operation of a plurality of hydraulic actuators including a hydraulic actuator having a high load pressure, and can improve the energy efficiency and simplify the valve configuration. A hydraulic control device for a machine is provided.

  According to a first aspect of the present invention, there is provided a hydraulic control device for a work machine including a hydraulic pump, a plurality of hydraulic actuators driven by the hydraulic pump, and a plurality of control valves for individually controlling the operations of the hydraulic actuators. A switching valve provided in the discharge line of the hydraulic pump, and a predetermined hydraulic actuator and control valve among the plurality of hydraulic actuators and control valves as a priority actuator and a priority control valve. And a control means for controlling the switching of the switching valve, the switching valve bypassing the priority valve for the pump discharge oil and the priority position for directing the pump discharge oil to the priority valve. Non-superior supply to hydraulic actuators other than the above-mentioned priority actuators in the path And a position, the control means of the switching valve, the priority position during operation of the priority control valve, at the time of non-operation of the priority control valve is one that is configured to switch each of the non-preferred position.

  According to a second aspect of the present invention, in the configuration of the first aspect, as the priority valve, a flow rate control valve with pressure compensation that performs flow rate control so as to maintain a constant differential pressure across the pressure oil supply opening of the priority control valve is provided. It was used.

  According to a third aspect of the present invention, in the configuration of the first or second aspect, the plurality of priority actuators and priority control valves and a plurality of priority valves corresponding thereto are provided, and the switching valve is provided in the plurality of priority valves. The control means has a plurality of corresponding priority positions, and the control means is configured to switch the switching valve between the plurality of priority positions in accordance with the operation of the plurality of priority control valves.

  According to a fourth aspect of the present invention, in the configuration according to any one of the first to third aspects, the priority valve is configured to supply a surplus amount of pump discharge oil supplied to the priority actuator to a hydraulic actuator other than the priority actuator. It is.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the hydraulic actuator selected from the left and right traveling motors of the hydraulic excavator, the turning motor, and the crushing cylinder as an optional actuator is prioritized as a priority actuator. A valve and a switching valve are provided.

  According to a sixth aspect of the present invention, in the configuration of the fifth aspect, the control unit has a plurality of hydraulic pumps, the left and right traveling motors as priority actuators, and the left traveling and right traveling control valves for controlling these operations as priority control valves. The switching valve is configured to join the oil discharged from the plurality of hydraulic pumps toward the priority valve when the two travel control valves are operated simultaneously.

  According to the present invention, when the predetermined priority control valve is operated, the pump discharge oil is preferentially supplied to the priority actuator via the switching valve and the priority valve. (In claim 4, the surplus is supplied to the other hydraulic actuators. Therefore, the necessary circuit flow rate of the priority actuator can be secured as a basic effect.

  Therefore, the priority actuator and other hydraulic actuators are operated simultaneously by preferentially controlling a hydraulic actuator with high load pressure (for example, the excavator travel motor, turning motor, crushing cylinder as in claim 5) as the priority actuator. During the combined operation, it is possible to solve the problem that the circuit flow rate of the priority actuator is insufficient and the operation speed decreases.

  Further, when only the non-priority actuator is operated, the pump discharge oil is supplied to these non-priority actuators through a path that bypasses the priority valve, so that the total actuator flow rate is reduced as in the known technique described in Patent Document 1. The pressure loss can be suppressed and energy efficiency can be improved as compared with the case where the throttle valve is throttled, and the circuit configuration can be simplified.

  In this case, according to the invention of claim 2, since the flow rate control valve with pressure compensation that performs flow rate control so as to keep the differential pressure across the pressure oil supply opening of the priority control valve constant is used as the priority valve. It is possible to solve the problem that the operating speed of the priority actuator (for example, the traveling motor) fluctuates due to the influence of the posture change of the work attachment (change in the load pressure of another hydraulic actuator).

  According to the invention of claim 3, in order to switch the actuator to be prioritized by switching the switching valve between a plurality of priority positions according to the operation of the priority control valve, each having a plurality of priority actuators, priority control valves and priority valves. In a work machine including a plurality of high load pressure actuators such as a hydraulic excavator, the problem of a decrease in the operating speed of each high load actuator during combined operation can be solved.

  According to the invention of claim 6, in the hydraulic excavator, when the left and right traveling motors are simultaneously operated (at the time of straight travel), the switching oil is used to join the discharge oil of the plurality of hydraulic pumps toward the priority valve. Since the function of the straight travel valve in the shovel circuit is performed by the switching valve, it is not necessary to provide a separate travel straight valve. For this reason, the circuit configuration can be further simplified.

  In the following embodiments, a hydraulic excavator diverted to a crusher is taken as an example of application in accordance with the description of the background art.

1st Embodiment (refer FIG. 1)
In this hydraulic excavator, as a hydraulic actuator, in addition to the boom, arm, and bucket cylinders 6 to 8, a turning motor 10, left and right traveling motors 11L and 11R, and a crushing cylinder 12 for a crushing device are provided. Each is controlled by hydraulic pilot control valves 13-19.

  In addition, remote control valves 20 to 26 are provided for the respective control valves, and the control valves 13 to 19 are operated by the pilot pressure from the remote control valves 20 to 26, so that the actuators 6 to 8, 10, 11L, 11R, 12 are operated. Is controlled.

  In the first embodiment, the left and right traveling motors 11L and 11R and their control valves 16 and 19 are used as a first priority actuator and a priority control valve, and the crushing cylinder 12 and its control valve 15 are a second priority actuator and a priority control valve. This is the case.

  On the other hand, first and second hydraulic pumps 27 and 28 are provided as hydraulic sources for the hydraulic actuator group, and a hydraulic pilot type switching valve 29 is provided in the discharge line of both the hydraulic pumps 27 and 28. A first priority valve 30 for traveling priority and a second priority valve 31 for crushing priority are provided on the downstream side.

  The switching valve 29 includes, in order from the left side of the drawing, a crushing priority position a that preferentially supplies pump discharge oil to the crushing cylinder 12, and a travel priority position b that preferentially supplies pump discharge oil to the traveling motors 11L and 11R. The non-priority position C for canceling the priority, and the four driving positions D for driving the left and right traveling motors 11L and 11R with separate pumps, and the four positions according to the pilot pressure applied to the pilot port 29a. Switches between positions and operates.

  The first and second priority valves 30 and 31 have a differential pressure before and after the pressure oil supply opening of the priority control valve (the former is the traveling control valves 16 and 19 and the latter is the crushing control valve 15) in addition to the priority function. It functions as a flow control valve with pressure compensation that performs flow control so as to keep the flow constant.

  More specifically, both priority valves 30, 31 are configured as hydraulic pilot valves having priority pilot ports 30a, 31a on one side and non-priority pilot ports 30b, 31b on the opposite side, and both pilot ports 30a, 31a, 30b. , 31b, the position is switched between the priority position A and the non-priority position B and the flow rate is controlled.

  The first priority valve 30 includes a passage leading to the pressure oil supply openings of the travel control valves 16 and 19 through the travel conduits 32 a and 32 b, and both the boom and the arm via the boom / bucket conduit 33. A passage leading to the pressure oil supply opening of the control valves 17 and 18 is provided.

  Then, the pump discharge oil is preferentially supplied to both the traveling control valves 17 and 18 at the priority position a on the right side of the figure, and the surplus is supplied to both the boom and bucket control valves 17 and 18.

  The second priority valve 31 includes a passage leading to the crushing control valve 15 through the crushing pipe line 34, and pressure oil supply openings of both the arm control valve and the turning control valves 13 and 14 through the arm / swing pipe 35. And a passage leading to.

  Then, the pump discharge oil is preferentially supplied to the crushing control valve 15 at the priority position a on the left side of the figure, and the surplus is supplied to both the arm control valve and the turning control valves 13 and 14.

  On the other hand, the load pressure when the traveling motor is operated is applied to the priority pilot port 30a of the first priority valve 30, and the supply pressure when the traveling motor is operated is applied to the non-priority pilot port 30b as the pilot pressure.

  A load pressure during operation of the crushing cylinder is applied to the priority side pilot port 31a of the second priority valve 31, and a supply pressure during operation of the crushing cylinder is applied to the non-priority side pilot port 31b.

  By these pilot pressures, both priority valves 30, 31 are switched between the priority position A and the non-priority position B, and the differential pressure across the pressure oil supply opening of the control valve 16, 19, 15 for traveling or crushing. The flow rate is controlled to keep the constant.

  The pilot port 29 a of the switching valve 29 is connected to a pilot pressure control valve 37 (which constitutes a control means) that is an electromagnetic proportional valve controlled by the controller 36, and is controlled from the pilot pressure control valve 37. Pressure is applied as a pilot pressure.

  Signals (operation signals in FIG. 1) from pressure sensors 38 to 44 that detect the operations of the remote control valves 20 to 26 by the respective remote control pressures are input to the controller 36, and the controller 36 according to the operation signals receives the signals. The switching valve 29 is switched between the positions A and D by the control pressure from the pilot pressure control valve 37 based on the command.

  The operation of this control device including the operation of this point will be described.

I. During combined operation including traveling When the left and right traveling remote control valves 23 and 26 are operated, operation signals from the pressure sensors 41 and 44 are input to the controller 36, and the switching valve 29 is supplied from the controller 36 via the pilot pressure control valve 37. The switching valve 29 is switched to the travel priority position B shown in FIG.

  In this travel priority position b, the oil discharged from both hydraulic pumps 27 and 28 is preferentially supplied to the left and right travel motors 11L and 11R via the first priority valve 30 and the travel control valves 16 and 19, and the surplus amount is supplied. It is sent to both boom and bucket control valves 17 and 18 via the boom / bucket conduit 33.

  Here, the first priority valve 30 takes in the load pressure of the travel motors 11L and 11R as a pilot pressure, and when the load pressure increases, the opening degree leading to the travel pipelines 32a and 32b increases. Conversely, when the load pressure decreases, the opening degree that leads to the travel pipelines 32a and 32b is set to be small.

  As a result, the first priority valve 30 preferentially supplies a constant flow rate to both the travel motors 11L and 11R regardless of fluctuations in the load pressure of the travel motors 11L and 11R.

  On the other hand, when the switching valve 29 is in the travel priority position b, the passage leading to the second priority valve 31 is blocked, and the pump discharge oil to the arm control valve, the turning control valve 13 to the control valve 13-15. Is supplied by bypassing the second priority valve 31.

  When the switching valve 29 is at the travel priority position b, the oil discharged from both the hydraulic pumps 27 and 28 merges in the switching valve 29 as shown in the figure, and this combined oil is used as described above for both the traveling motors 11L, 11R.

  That is, in the conventional excavator circuit, the travel straight valve for driving the left and right traveling motors at the same speed with the same amount and pressure of oil is performed by the switching valve 29 at the traveling priority position b.

II. At the time of compound operation including crushing In this case, the switching valve 29 is switched to the crushing priority position a.

  In this crushing priority position a, the discharge oil of the first hydraulic pump 27 is preferentially given to the crushing cylinder 12 through the switching valve 29, the priority position i of the second priority valve 31, the crushing conduit 34, and the path of the crushing control valve 15. The surplus is supplied to the arm / swivel pipe 35.

  At this time, since the load pressure of the crushing cylinder 12 is applied to the second priority valve 31 as a pilot pressure, a constant flow rate is allowed to flow regardless of fluctuations in the load pressure of the crushing cylinder 12 as with the first priority valve 30. Control is performed.

III. When there is no traveling operation and crushing operation and other operations are performed In this case, the switching valve 29 is switched to the non-priority position C.

  In this non-priority position C, the oil discharged from both the hydraulic pumps 27 and 28 passes through the passage motors 11L, 11R and the bypass passages (the arm / swivel pipeline 35 and the boom / bucket pipeline 33). It is supplied to non-priority actuators (arm cylinder 7, turning motor 10, boom cylinder 6, bucket cylinder 8) other than the crushing cylinder 12.

IV. At the time of operation only for traveling In this case, the switching valve 29 is switched to the driving position D for each traveling.

  At the driving position D for each travel, the oil discharged from the first hydraulic pump 27 is supplied to the left travel motor 11L, and the oil discharged from the second hydraulic pump 28 is supplied to the right travel motor 11R via the control valves 16 and 19, respectively. .

  That is, the left and right traveling motors 11L and 11R are driven by separate pumps.

  As described above, the pump discharge oil is preferentially supplied to the traveling motors 11L and 11R as traveling priority during combined operation including traveling operation, and to the crushing cylinder 12 as prioritized crushing during combined operation including crushing operation. Therefore, it is possible to solve the problem that the circuit speed of the traveling motors 11L, 11R or the crushing cylinder 12 having a high load pressure is insufficient at the time of the combined operation and the operation speed is lowered.

  Further, since the flow rate control valve with pressure compensation is used as the priority valves 30 and 31, and a constant flow rate is supplied to these regardless of fluctuations in the load pressure of the traveling motors 11L and 11R or the crushing cylinder 12, they are shown in FIG. The problem that the operating speeds of the priority actuators (travel motors 11L, 11R and crushing cylinder 12) fluctuate under the influence of the posture change of the work attachment A (changes in load pressure of other hydraulic actuators) can also be solved. .

  Further, when only the non-priority actuators (the boom, arm, bucket cylinders 6 to 8 and the swing motor 10) are operated, the pump discharge oil is supplied to the non-priority actuators 6 to 8 and 10 through a path bypassing the priority valves 30 and 31. Therefore, the pressure loss can be suppressed and the energy efficiency can be improved as compared with the case where the entire actuator flow rate is throttled by the throttle valve as in the known technique described in Patent Document 1, and the circuit configuration can be improved. It can be simplified.

  On the other hand, when the left and right traveling motors 11L, 11R are operated simultaneously (straightly traveling), the configuration is such that the oil discharged from both the hydraulic pumps 27, 28 is merged by the switching valve 29 and directed to the priority valve 30, that is, a conventional shovel circuit. Since the function of the straight travel valve is performed by the switching valve 29, there is no need to provide a separate travel straight valve. For this reason, the circuit configuration can be further simplified.

Second embodiment (see FIG. 2)
In the following second and third embodiments, only differences from the first embodiment will be described.

  In the second embodiment, as a configuration when the load pressure of the swing motor 10 is higher than the load pressure of the crushing cylinder 12, the second priority valve 31 replaces the crush cylinder 12 of the first embodiment with the swing motor 10. The structure which supplies a pump discharge oil preferentially is taken.

  Other configurations including the point that the pump discharge oil is preferentially supplied to the left and right traveling motors 11L, 11R by the first priority valve 30 are the same as those in the first embodiment.

  In this case, since the valve configurations of both the turning and crushing control valves 14 'and 15' need to be different from those of the turning control valves 14 and 15 of the first embodiment, different reference numerals are given respectively. Further, the “arm / swivel pipeline” 35 of the first embodiment is an “arm / crushing pipeline”.

3rd Embodiment (refer FIG. 3)
In the third embodiment, as a variation of the first embodiment, the second priority valve 45 for crushing priority is opened by a pilot pressure applied from the pilot pressure control valve 46 to the pilot port 45a based on a command from the controller 36. A throttle valve with varying degrees is used.

  According to this configuration, the pipe 47 leading to the arm / swivel pipe 35 is throttled by the second priority valve 45, whereby the pump discharge oil is preferentially supplied to the crushing cylinder 12 via the crushing control valve 15 '. The

  However, in this case, the flow rate control action with pressure compensation as in the second priority valve 31 of both the first and second embodiments is not performed.

  Other configurations and operations are basically the same as those of the first embodiment, and basically the same effects as those of the first embodiment can be obtained.

It is a circuit block diagram which shows 1st Embodiment of this invention. It is a circuit block diagram which shows 2nd Embodiment of this invention. It is a circuit block diagram which shows 3rd Embodiment of this invention. It is a schematic side view of a hydraulic excavator. It is a schematic side view of the state which diverted the hydraulic excavator to the crusher.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lower traveling body of hydraulic excavator 2 Same as above, Upper turning body 3 Boom 4 Arm 5 Bucket 6 Boom cylinder 7 Arm cylinder 8 Bucket cylinder 9 Crushing device 10 Turning motor 11L Traveling motor 11R Right traveling motor 12 Crushing cylinder 13-19 Control valve 27 , 28 Hydraulic pump 29 Switching valve 30 First priority valve 31 Second priority valve 36 Controller constituting control means 37 Pilot pressure control valve 38-44 Pressure sensor for detecting operation 45 Second priority valve 46 Pilot pressure control valve

Claims (6)

  In a hydraulic control device for a work machine, comprising a hydraulic pump, a plurality of hydraulic actuators driven by the hydraulic pump, and a plurality of control valves for individually controlling the operations of the hydraulic actuators, a discharge pipe of the hydraulic pump A switching valve provided on the road; a priority valve for preferentially supplying pump discharge oil to these hydraulic actuators and control valves as a priority actuator and priority control valve among the plurality of hydraulic actuators and control valves; Control means for controlling the switching of the switching valve, the switching valve having a priority position for directing pump discharge oil to the priority valve, and a path bypassing the priority valve for pump discharge oil other than the priority actuator. A non-priority position for supplying to the hydraulic actuator, and The control means is configured to switch the switching valve to a priority position when the priority control valve is operated, and to the non-priority position when the priority control valve is not operated, respectively. .   2. The operation according to claim 1, wherein the priority valve is a flow rate control valve with pressure compensation for performing flow rate control so as to keep a differential pressure across the pressure oil supply opening of the priority control valve constant. Hydraulic control device of the machine.   A plurality of priority actuators and priority control valves, and a plurality of priority valves corresponding thereto, wherein the switching valve has a plurality of priority positions corresponding to the plurality of priority valves; The hydraulic control device for a work machine according to claim 1 or 2, wherein the switching valve is switched between the plurality of priority positions in accordance with an operation of the priority control valve.   The work machine according to any one of claims 1 to 3, wherein the priority valve is configured to supply a surplus amount of pump discharge oil supplied to the priority actuator to a hydraulic actuator other than the priority actuator. Hydraulic control device.   5. A priority valve and a switching valve are provided using a hydraulic actuator selected from left and right traveling motors of a hydraulic excavator, a turning motor, and a crushing cylinder as an optional actuator as a priority actuator. The hydraulic control device for a work machine according to any one of the preceding claims.   It has a plurality of hydraulic pumps, left and right traveling motors as priority actuators, both left and right traveling control valves that control their operation as priority control valves, and the switching valve is operated simultaneously with both traveling control valves. 6. The hydraulic control device for a work machine according to claim 5, wherein the hydraulic oil discharged from the plurality of hydraulic pumps is sometimes combined and directed to a priority valve.

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