JP2010210072A - Hydraulic control system for working machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic control system for a working machine making the efficiency of recycling return fluid better than before determining the percentage of the recycled return fluid and the timing of recycling regardless of the supply and discharge of hydraulic fluid to and from a hydraulic actuator. <P>SOLUTION: The hydraulic control system includes a first control valve 14 for controlling the supply and discharge of hydraulic fluid to and from the hydraulic actuator 20, and a second control valve 16 provided in the passage for hydraulic fluid between the hydraulic actuator 20 and the first control valve 14 and having a recycling circuit 18 for recycling the return fluid from the hydraulic actuator 20. The second control valve 16 can operate independently of the first control valve 14. The adjustment of at least either of the percentage of recycled the return fluid and the timing of recycling is not related to the control of the supply and discharge of the hydraulic fluid by the first control valve 14. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a hydraulic control system for a work machine having a function of reclaiming and returning return oil from a hydraulic actuator.

  Patent Document 1 describes a hydraulic control system for a work machine having a function of reclaiming and returning return oil from a hydraulic cylinder. FIG. 3 is a block diagram of an example of a hydraulic control system based on the same technical idea as the hydraulic control system described in Patent Document 1. FIG. 4 is an enlarged view showing the control valve 104 of FIG. is there.

  The control valve 104 includes a regeneration circuit 106 that controls the supply and discharge of the hydraulic oil to and from the hydraulic cylinder 108 and exhibits a function of reclaiming and returning the return oil at the switching position G. The hydraulic cylinder 108 and the control valve 104 are connected via piping 110a, 110b, 110c, 110d and hoses 112a, 112b due to installation restrictions.

  When the return oil discharged from the bottom side 108a of the hydraulic cylinder 108 is regenerated to the rod side 108b, the return oil passes from the bottom side 108a of the hydraulic cylinder 108 to the control valve 104 via the pipe 110a, the hose 112a, and the pipe 110c. enter. Then, the return oil is throttled by the throttle valve 106e in the tank return oil passage 106a of the regeneration circuit 106 in the control valve 104, and a part thereof enters the regeneration oil passage 106c, passes through the check valve 106d, and is supplied to the cylinder supply oil. The hydraulic oil supplied from the main pump 102 joins in the path 106b. After merging, it is guided to the rod side 108b of the hydraulic cylinder 108 through the pipe 110d, the hose 112b, and the pipe 110b.

  In this way, the hydraulic control system 100 returns to the hydraulic oil supplied from the main pump 102 and joins the oil, so that the speed of the hydraulic cylinder 108 can be improved and the amount of hydraulic oil supplied by the main pump 102 Can be reduced (that is, the amount of energy for driving the main pump 102 can be reduced). Further, it contributes to prevention of cavitation in the hydraulic cylinder 108.

Japanese Patent Laid-Open No. 9-210006

  However, in the hydraulic control system 100, the regeneration circuit 106 is provided in the control valve 104 that controls the supply and discharge of hydraulic oil to and from the hydraulic cylinder 108, and determines the direction and amount of supply and discharge of hydraulic oil to and from the hydraulic cylinder 108. Depending on the position of the spool of the control valve 104, the ratio of the recycled oil to be recycled and the regeneration timing are determined. For this reason, it is not possible to determine the ratio of recycling of the return oil and the regeneration timing irrespective of the supply and discharge of the hydraulic oil to and from the hydraulic cylinder 108, and the efficiency of recycling of the return oil is not sufficient.

  The present invention has been made in view of such problems, and when the return oil discharged from the hydraulic actuator is reclaimed in the hydraulic actuator, the ratio of the return oil to be recycled and the regeneration timing are: It is an object of the present invention to provide a hydraulic control system for a work machine that can be determined independently of the supply and discharge of hydraulic oil to and from the hydraulic actuator and that has improved the efficiency of recycling recycled oil as compared with the prior art.

  The present invention provides a hydraulic control system for a work machine having a function of reclaiming return oil from a hydraulic actuator, a first control valve that controls supply and discharge of hydraulic oil to and from the hydraulic actuator, the hydraulic actuator, and the first A second control valve provided in a passage of hydraulic oil to and from the control valve and provided with a regeneration circuit for reclaiming and returning the return oil from the hydraulic actuator, wherein the second control valve is the first control It can operate independently of the valve, and the adjustment of at least one of the ratio of recycled oil and the regeneration timing of the return oil is independent of the control of the supply and discharge of the hydraulic oil by the first control valve The above-mentioned problems are solved by being possible.

  The present invention includes a first control valve that controls supply and discharge of hydraulic oil to and from the hydraulic actuator, and a second control valve that includes a regeneration circuit for reclaiming and returning the return oil from the hydraulic actuator. Has the two functions that one control valve has been assigned to, the first control valve and the second control valve, respectively, and the second control valve can operate independently of the first control valve. .

  For this reason, it is possible to adjust the ratio of recycling of the return oil and the regeneration timing regardless of the control of the supply and discharge of the hydraulic oil by the first control valve, thereby improving the efficiency of the return oil regeneration. Can be made.

  In the present invention, since the second control valve is disposed in the hydraulic oil passage between the hydraulic actuator and the first control valve, the return oil regenerated through the regeneration circuit in the second control valve. The length of the passage through which can pass can be made shorter than before, and passage loss can be reduced. Therefore, the reproduction efficiency can be improved.

  In addition, the passage loss when the return oil is regenerated can be reduced by increasing the cross-sectional area of the passage and by increasing the throttle area (flow-path cross-sectional area) of the throttle valve in the regeneration circuit. In the present invention, since the second control valve is disposed in the hydraulic oil passage between the hydraulic actuator and the first control valve, the length of the passage through which the return oil to be regenerated passes is made shorter than before. And the length of the passage where the cross-sectional area should be increased can be shortened. Therefore, the modification for enlarging the cross-sectional area to reduce the passage loss during the regeneration is relatively easy, and the modification for improving the regeneration efficiency is easier than before.

  From the above, according to the present invention, the regeneration efficiency of the hydraulic control system can be increased.

  In the hydraulic control system according to the present invention, the second control valve may be, for example, an operation amount / operation speed of an operation lever for operating the first control valve, a speed of an operating portion of the hydraulic actuator, At least of the magnitude of the force applied to the object, the pressure / temperature of the hydraulic oil in the hydraulic actuator, the discharge amount of the hydraulic pump that supplies the hydraulic oil to the hydraulic actuator, and the rotational speed of the engine that drives the hydraulic pump The hydraulic control system may be configured to be controlled depending on one.

  In the present invention, since the second control valve is disposed in the hydraulic oil passage between the hydraulic actuator and the first control valve, for example, the hydraulic oil flows out from the hydraulic actuator to the second control valve. When the hose and piping on the main pump side of the second control valve are damaged, the position of the operating portion of the hydraulic actuator can be maintained.

  In addition, when the second control valve is attached to the hydraulic actuator, piping between the second control valve and the hydraulic actuator can be minimized.

  ADVANTAGE OF THE INVENTION According to this invention, the efficiency at the time of recycle | reusing the return oil discharged | emitted from the hydraulic actuator in this hydraulic actuator can be improved rather than before.

1 is a block diagram showing a hydraulic control system 10 for a work machine according to an embodiment of the present invention. The enlarged view of the principal part (2nd control valve 16) of the said hydraulic control system 10 Block configuration diagram of an example of a hydraulic control system based on the same technical idea as the hydraulic control system described in Patent Document 1 The enlarged view of the principal part (control valve 104) of an example of the said hydraulic control system

  Hereinafter, an example of a preferred embodiment of a hydraulic control system for a work machine according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a block diagram showing a hydraulic control system 10 for a work machine according to an embodiment of the present invention.

  As shown in FIG. 1, the hydraulic control system 10 includes a main pump 12, a first control valve 14, a second control valve 16, a regeneration circuit 18, and a hydraulic cylinder 20.

  The first control valve 14 is a three-position six-port switching valve, and includes three switching positions A, B, and C, and controls supply and discharge of hydraulic oil to and from the hydraulic cylinder 20. Pilot ports 14a and 14b are provided at both ends of the spool of the first control valve 14, respectively. Further, both ends of the spool of the first control valve 14 are biased by springs 14c and 14d.

  The spool position of the first control valve 14 is switched by operating the remote control lever device 22 to control the pilot pressure supplied to the pilot ports 14a and 14b of the first control valve 14. Pilot pressure is supplied to the pilot ports 14a and 14b via the pilot oil passages 24a and 24b.

  When the operation lever 22a of the remote control lever device 22 is tilted in the L direction, the pilot pressure is supplied to the pilot oil passage 24a, and the spool of the first control valve 14 moves to the switching position A side. When the operation lever 22a of the remote control lever device 22 is tilted in the R direction, the pilot pressure is supplied to the pilot oil passage 24b, and the spool of the first control valve 14 moves to the switching position C side.

  The second control valve 16 is provided in a hydraulic oil passage between the hydraulic cylinder 20 and the first control valve 14 (between the pipes 30a and 30b and the pipes 30c and 30d). The return oil is re-supplied to the hydraulic cylinder 20 and recycled. Pilot ports 16a and 16b are provided at both ends of the spool of the second control valve 16, respectively. Further, both ends of the spool of the second control valve 16 are urged by springs 16c and 16d.

  The second control valve 16 is a three-position / four-port switching valve and includes three switching positions D, E, and F. At the switching position D, a regeneration circuit 18 is provided, and the return oil from the hydraulic cylinder 20 is regenerated. At the switching position E, the hydraulic oil is not regenerated and the rod 20c (operating part) of the hydraulic cylinder 20 is held. At the switching position F, the hydraulic oil is not regenerated and the return oil from the hydraulic cylinder 20 is drained to the full tank 50.

  As shown in an enlarged view in FIG. 2, the regeneration circuit 18 is provided at the switching position D of the second control valve 16, and includes a tank return oil passage 18a, a cylinder supply oil passage 18b, and a tank return oil passage 18a. A regeneration oil passage 18c communicating from the intermediate point to the intermediate point of the cylinder supply oil passage 18b, a check valve 18d interposed in the regeneration oil passage 18c, and the main pump 12 in the tank return oil passage 18a rather than the regeneration oil passage 18c. And a throttle valve 18e provided on the side.

  Switching of the spool position of the second control valve 16 is controlled by the controller 26. The controller 26 sends an electric signal to the solenoid portion of the electromagnetic proportional valve 27 via the electric signal lines 26a and 26b, thereby controlling the position of the spool of the electromagnetic proportional valve 27, and thereby via the pilot oil passages 28a and 28b. The pilot pressure supplied to the pilot ports 16a and 16b of the second control valve 16 is controlled. The electrical signal sent from the controller 26 to the solenoid portion of the electromagnetic proportional valve 27 is automatically controlled by the controller 26 based on various parameters, whereby the pilot pressure supplied to the pilot ports 16a and 16b of the second control valve 16 is automatically controlled. Is done.

  When pilot pressure is supplied to the pilot port 16a via the pilot oil passage 28a, the spool of the second control valve 16 moves to the switching position D side, and pilot pressure is supplied to the pilot port 16b via the pilot oil passage 28b. Then, the spool of the second control valve 16 moves to the switching position F side. When the spool of the second control valve 16 is moved to the switching position D side, the tank return oil passage 18a in the second control valve 16 is connected to the pipes 30a and 30c, and the cylinder supply oil in the second control valve 16 The path 18b is connected to the pipes 30b and 30d, and the regeneration circuit 18 exhibits a function of reclaiming and returning the return oil.

  In this embodiment, the position of the spool of the first control valve 14 is switched by the pilot pressure supplied via the remote control lever device 22, and the position of the spool of the second control valve 16 is switched from the controller 26. Since the pilot pressure supplied through the electromagnetic proportional valve 27 controlled based on the electric signal is used, the switching of the spool position of the second control valve 16 is irrelevant to the switching of the spool position of the first control valve 14. Can be done independently.

  Here, the spool of the second control valve 16 does not switch stepwise between the switching position D for regeneration and the neutral position E, but smoothly between the switching position D and the neutral position E. Switching is possible. Therefore, by controlling the position of the spool of the second control valve 16 to a predetermined position between the neutral position E and the switching position D, it is possible to variably control the proportion of the return oil that is recycled. .

  Therefore, the controller 26 can optimally adjust the ratio of recycled oil and / or the timing of regeneration according to various parameters that display the operation status of the hydraulic cylinder 20.

  As various parameters used by the controller 26 for automatic control, for example, the operation amount / operation speed (operation input value of the operator) of the operation lever 22a of the remote control lever device 22, the meter in-line pressure, the rod 20c of the hydraulic cylinder 20 (operation unit) ) Speed / position, the magnitude of the force applied by the operating part to the object, the pressure / temperature of the hydraulic oil in the hydraulic cylinder 20, the discharge amount / tilt angle of the main pump 12, the engine driving the main pump 12 The rotational speed / throttle opening, the attitude of the aircraft, the load force that the aircraft holds during work, and the like can be mentioned. Any one of these may be used as a parameter, or may be configured to adjust based on a result obtained by combining a plurality of parameters.

  For example, when the operation speed when operating the operation lever 22a of the remote control lever device 22 to supply the hydraulic oil to the rod side 20b of the hydraulic cylinder 20 and raise the rod 20c (operation unit) is high, Since it is preferable to increase the acceleration of the operation of the rod 20c, the amount of return oil regenerated is increased.

  The connection between the hydraulic cylinder 20 and the second control valve 16 is made through the pipes 30a and 30b. The connection between the second control valve 16 and the first control valve 14 is made via pipes 30c, 30d, 30e, 30f and hoses 32a, 32b. When the operation lever 22a of the remote control lever device 22 is tilted in the L direction, the spool of the first control valve 14 becomes the switching position A, the controller 26 supplies the pilot pressure to the pilot port 16a, and the spool of the second control valve 16 At the switching position D, the pipes 30a, 30c, the hose 32a, and the pipe 30e become the discharge side that discharges the return oil from the bottom side 20a of the hydraulic cylinder 20, and the pipes 30b, 30d, the hose 32b, and the pipe 30f return the hydraulic oil to the hydraulic cylinder. It becomes the supply side which supplies to 20 rod side 20b.

  Further, since the second control valve 16 is closer to the hydraulic cylinder 20 than the hoses 32a and 32b, the pressure from the main pump 12 is applied to the rod side 20b of the hydraulic cylinder 20 by setting the second control valve 16 to the neutral position D. Since the oil is supplied and the return oil from the bottom side 20a is prevented from flowing out, for example, even when the hose 32a is broken, the flow of the hydraulic oil to the hydraulic cylinder 20 is stopped, and the hydraulic oil is discharged from the hydraulic cylinder 20. It is possible to prevent the fluid from flowing out, and to have a function of holding the position of the rod 20c (operation part) of the hydraulic cylinder 20.

  Moreover, the 2nd control valve 16 may be attached to the hydraulic cylinder 20, In this case, the length of piping 30a, 30b can be shortened, and the structure of an apparatus can be simplified.

  In the present embodiment, since the two functions are respectively assigned to the first control valve 14 and the second control valve 16, the size of each control valve can be made smaller than that of the conventional control valve. In particular, the size of the second control valve 16 that has only to have at least a function of regenerating the return oil from the hydraulic cylinder 20 can be made smaller than that of the conventional control valve. For this reason, the second control valve 16 can be easily attached to the hydraulic cylinder 20.

  Next, the operation of the hydraulic control system 10 for a work machine according to the embodiment of the present invention configured as described above will be described.

  When the spool of the second control valve 16 is set to the switching position D and the return oil discharged from the bottom side 20a of the hydraulic cylinder 20 is regenerated to the rod side 20b, the return oil is supplied from the bottom side 20a of the hydraulic cylinder 20 to the pipe 30a. Then, the second control valve 16 is entered. The return oil is squeezed by the throttle valve 18e in the tank return oil passage 18a of the regeneration circuit 18 in the second control valve 16, and a part of the return oil enters the regeneration oil passage 18c, passes through the check valve 18d, and reaches the cylinder. It merges with the hydraulic oil supplied from the main pump 12 through the supply oil passage 18b. After merging, the pipe 30b is led to the rod side 20b of the hydraulic cylinder 20 for recycling.

  As described above, conventionally, one control valve is provided with the function of controlling the supply and discharge of hydraulic oil to and from the hydraulic cylinder 20 and the function of regenerating the return oil from the hydraulic cylinder 20, but this embodiment In the hydraulic control system 10 according to the embodiment, a first control valve 14 having a function of controlling supply / discharge of hydraulic oil to / from the hydraulic cylinder 20 and a second function of regenerating return oil from the hydraulic cylinder 20 are provided. The control valve 16 is provided, and the two functions that have conventionally been performed by one control valve are shared by the first control valve 14 and the second control valve 16, respectively. It can operate independently of the first control valve 14.

  For this reason, it is possible to adjust the ratio of recycled oil and / or the timing of regeneration in the return oil from the bottom side 20a of the hydraulic cylinder 20 irrespective of the control of the supply and discharge of the hydraulic oil by the first control valve 14. Thus, the efficiency of regeneration of the return oil can be improved. In the present embodiment, the ratio of the recycled oil in the return oil and / or the timing of the regeneration is adjusted by the controller 26 using the various parameters as described above for the position of the spool of the second control valve 16 by the pilot pressure. This is done by automatic control.

  In the present embodiment, since the second control valve 16 is disposed in the hydraulic oil passage between the hydraulic cylinder 20 and the first control valve 14, the return oil from the bottom side 20a of the hydraulic cylinder 20 is the first. The pipes 30c, 30d, 30e, 30f and the hoses 32a, 32b between the first control valve 14 and the second control valve 16 are not passed. For this reason, the length of the passage through which the return oil regenerated through the regeneration circuit in the second control valve 16 passes can be made shorter than before, and passage loss can be reduced. Therefore, the reproduction efficiency can be improved.

  In addition, the passage loss when the return oil is regenerated can be reduced by increasing the cross-sectional area of the passage and by increasing the throttle area (flow-path cross-sectional area) of the throttle valve in the regeneration circuit. In the present embodiment, the length of the passage through which the regenerated return oil passes can be made shorter than before, so that the length of the passage whose cross-sectional area should be increased can also be shortened. Therefore, the modification for enlarging the cross-sectional area to reduce the passage loss during the regeneration is relatively easy, and the modification for improving the regeneration efficiency is easier than before.

  From the above, in the hydraulic control system 10 according to the present embodiment, the efficiency of regeneration of the return oil from the hydraulic cylinder 20 can be increased.

  Further, since the return oil from the hydraulic cylinder 20 does not pass through the piping 30c, 30d, 30e, 30f and the hoses 32a, 32b between the first control valve 14 and the second control valve 16, the piping 30c, The flow path cross-sectional areas of 30d, 30e, 30f and the hoses 32a, 32b can be reduced, and the cost for implementing the hydraulic control system 10 according to the present embodiment can be reduced.

  The present invention can be effectively applied to a work machine (for example, a hydraulic excavator) having a function of recycling the return oil from the hydraulic actuator.

DESCRIPTION OF SYMBOLS 10 ... Hydraulic control system 12 ... Main pump 14 ... 1st control valve 16 ... 2nd control valve 18 ... Regeneration circuit 18a ... Tank return oil path 18b ... Cylinder supply oil path 18c ... Regeneration oil path 18d ... Check valve 18e ... Throttle valve DESCRIPTION OF SYMBOLS 20 ... Hydraulic cylinder 20a ... Bottom side 20b ... Rod side 20c ... Rod 22 ... Remote control lever device 26 ... Controller

Claims (4)

In a hydraulic control system for a work machine having a function of reclaiming return oil from a hydraulic actuator,
A first control valve for controlling supply and discharge of hydraulic oil to and from the hydraulic actuator;
A second control valve provided in a passage of hydraulic oil between the hydraulic actuator and the first control valve, and having a regeneration circuit for reclaiming and returning the return oil from the hydraulic actuator;
With
The second control valve can operate independently of the first control valve, and the adjustment of at least one of the recycled oil ratio and the regeneration timing of the return oil is performed by the first control valve. A hydraulic control system for a work machine, which is possible regardless of control of supply and discharge of hydraulic oil. In claim 1,
The second control valve is an operation amount / operation speed of an operation lever for operating the first control valve, a speed of an operating portion of the hydraulic actuator, a magnitude of a force applied to the object by the operating portion, The hydraulic oil is controlled depending on at least one of the pressure and temperature of the hydraulic oil, the discharge amount of the hydraulic pump that supplies the hydraulic oil to the hydraulic actuator, and the rotational speed of the engine that drives the hydraulic pump. Hydraulic control system for working machines. In claim 1 or 2,
The hydraulic control system for a work machine, wherein the second control valve has a function of stopping outflow of hydraulic oil from the hydraulic actuator. In any one of Claims 1-3,
The hydraulic control system for a work machine, wherein the second control valve is attached to the hydraulic actuator.

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