JP2009204074A - Drive control device for hydraulic actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the following property of a second hydraulic actuator when reducing the amount of operation of a first operation means in the state that a second operation means and the first operation means are each operated in one direction. <P>SOLUTION: An operation control means 60 has a piston member 61, and a control spring member 62. With the piston member 61 degenerated, it allows one-direction movement of a bucket spool 210 of a bucket operation valve 20 up to a position where a bucket branch supply passage 30B is opened. With the piston member 61 arranged at an advance position, it abuts on the bucket spool 210 to prevent one-direction movement thereof up to a position where the bucket branch supply passage 30B is opened. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a drive control device for a hydraulic actuator suitable for a construction machine that performs a desired work by operating a plurality of hydraulic actuators such as a wheel loader and a skid steer loader.

  An example of this type of drive control device is disclosed in Patent Document 1. This drive control device is configured to control a bucket hydraulic cylinder actuator and an arm hydraulic cylinder actuator of a construction machine.

  A main supply passage leading to the hydraulic pump is branched and connected to the bucket operation valve and the arm operation valve provided corresponding to the two hydraulic cylinder actuators, and discharged from the arm hydraulic cylinder actuator. A regeneration supply passage for supplying oil to the bucket hydraulic cylinder actuator is connected.

  In this drive control device, when the arm operation lever is operated in the arm lift direction, the regeneration supply passage is in a communication state, and the oil discharged from the arm hydraulic cylinder actuator is supplied to the bucket hydraulic cylinder actuator. That is, when the arm control lever is operated in the arm lift direction, the oil supply circuit for the two hydraulic cylinder actuators becomes a series circuit, and the operating speed of each hydraulic cylinder actuator is ensured regardless of the load pressure. It is possible to perform leveling control for driving the arm in the lift direction while maintaining the bucket posture.

  On the other hand, when the load pressure of the bucket hydraulic cylinder actuator exceeds a certain value in the above state, the regeneration cancel valve provided in the regeneration supply passage is switched, and all the oil discharged from the arm hydraulic cylinder actuator is discharged to the tank. The Accordingly, oil is supplied to the two hydraulic cylinder actuators through the respective branch supply passages branched from the main supply passage. That is, when the load pressure of the hydraulic cylinder actuator for the bucket exceeds a certain value, the oil supply circuit for the two hydraulic cylinder actuators becomes a parallel circuit. For example, if the bucket operation lever is operated in the bucket dump direction, a large drive The bucket can be dumped with force.

JP 2002-31104 A

  By the way, in the drive control device described above, when the bucket operation lever is operated in the bucket dump direction from the state where the arm operation lever is operated in the arm lift direction to perform leveling control, the bucket hydraulic cylinder actuator is passed through the regeneration supply passage. The flow rate of the oil supplied to is increased. Therefore, if the bucket operation lever is operated in the bucket dump direction from the leveling control state by the operation of the arm operation lever alone in the arm lift direction, the bucket dumping operation can be performed faster.

  Furthermore, in order to increase the dumping operation of the bucket from the state where the operation amount of the bucket operation lever is maximized, the operation amount of the arm operation lever may be decreased. That is, when the operation amount of the arm operation lever in the arm lift direction is reduced, the pilot pressure from the arm operation lever is also reduced, and the restriction state on the bucket operation valve of the operation control means based on this pilot pressure is relaxed / released. Thus, the bucket operation valve can be moved to a position where the branch supply passage is opened. On the other hand, the amount of oil supplied to the arm operation valve is reduced. For this reason, the total flow rate of the oil supplied from the hydraulic pump to the bucket hydraulic cylinder actuator through the branch supply passage increases, and the bucket dumping operation can be further accelerated.

  Here, when the operation amount of the arm operation lever in the arm lift direction is decreased from the state in which the operation amount of the bucket operation lever is maximized, the branch supply passage of the bucket operation valve is switched until the operation control means is switched. Is held in the closed state, and the branch supply passage of the bucket operation valve that was in the closed state at the time when the operation control means switched is opened. For this reason, even when the operation amount of the arm operation lever in the arm lift direction is decreased, the bucket dumping operation does not change until the operation control unit performs the switching operation. Thereafter, the operation amount of the arm operation lever is further reduced, and the amount of oil supplied to the bucket hydraulic cylinder actuator is increased when the operation control means is switched, and the bucket dumping operation is accelerated.

  Although such a phenomenon does not hinder the work of the construction machine, it is preferable to improve the followability of the hydraulic cylinder actuator with respect to the operation of the operator. The phenomenon described above is not limited to the drive control device to which the arm hydraulic cylinder actuator and the bucket hydraulic cylinder actuator are applied. That is, when each of the first operating means and the second operating means is operated in one direction, the second valve means closes the second branch supply passage by causing the operation control means to act on the second valve means, so that regeneration is supplied. When the amount of operation of the first operating means in one direction is reduced while the second operating means is operated in one direction while the passage is opened, the second valve means becomes the second branch supply passage. If it is configured so as to switch to a position where oil is supplied to the second hydraulic actuator, the same can occur.

  In view of the above circumstances, the present invention provides the following capability of the second hydraulic actuator when the operation amount of the first operation means is reduced in a state where the second operation means and the first operation means are each operated in one direction. It is an object of the present invention to provide a hydraulic actuator drive control device capable of improving the above.

  In order to achieve the above object, a drive control device for a hydraulic actuator according to claim 1 of the present invention includes a first hydraulic actuator that is controlled to supply and discharge oil via a first valve means, and a second valve means. A second hydraulic actuator for supplying and discharging oil and a main supply passage connected to the discharge port of the hydraulic pump branch from the first branch supply passage connected to the first valve means and the second valve means. A regeneration supply passage connecting the second branch supply passage, the first valve means and the second valve means, and supplying oil discharged from the first hydraulic actuator to the second hydraulic actuator; A first operating means provided corresponding to the first valve means; a second operating means provided corresponding to the second valve means; and the second valve when the first operating means is operated in one direction. Act on the means to control its switching action Operation control means, and when the first operation means and the second operation means are each operated in one direction, the second valve means is operated by causing the operation control means to act on the second valve means. While the second branch supply passage is closed and the regeneration supply passage is opened, the operation amount of the first operation means in one direction is reduced while the second operation means is operated in one direction. A drive control device for a hydraulic actuator configured to switch the second valve means to a position for supplying oil to the second hydraulic actuator through the second branch supply passage. The means has one end accommodated in a first pressure chamber provided in the valve body, and the other end accommodated in a second pressure chamber provided in the valve body. The first pressure chamber and the second pressure chamber Oil added to the chamber A spool that moves in the axial direction according to the difference between the two hydraulic actuators to control oil supply / discharge, and is interposed between the valve body and the spool and applied to the first pressure chamber. When the spool moves in one direction due to hydraulic pressure, it includes a pressing means that acts against this, and each of the first operating means and the second operating means has an individual operating direction. And a pilot pressure corresponding to each operation amount, and the operation control means is provided such that a distal end portion thereof is opposed to the spool in the second pressure chamber, while a proximal end portion is provided in the valve body. When the pilot pressure when the first operating means is operated in one direction is applied to the sub pressure chamber, the tip is directed toward the second pressure chamber. The piston member disposed at the advanced position and maintained between the advanced position, the valve body and the piston member, and the front end of the piston member advances toward the second pressure chamber And when the piston member is retracted, the spool of the second valve means is allowed to move in one direction to the position where the second branch supply passage is opened. When the member is disposed at the advanced position, it is prevented from moving in one direction to a position where it abuts on the spool and opens the second branch supply passage.

  According to a second aspect of the present invention, there is provided the hydraulic actuator drive control device according to the first aspect, wherein the pressing means includes a retainer disposed between the valve body and the spool, and the retainer and the valve. A first spring member interposed between the main body and a second spring member interposed between the spool and the retainer, the first spring member and the second spring member having different spring constants; It is characterized by being.

  According to a third aspect of the present invention, in the drive control device for a hydraulic actuator according to the first aspect, the piston member divides the sub pressure chamber into a first sub pressure chamber and a second sub pressure chamber. The first piston body, which is slidably disposed inside the sub pressure chamber and has a control spring member interposed between the valve body and the second pressure chamber, is arranged so as to move forward and backward. And a second piston body that can come into contact with the spool of the second valve means when moved forward, and is interposed between the first piston body and the second piston body so that they are separated from each other. The first piston body has a communication passage that communicates the first sub pressure chamber and the second sub pressure chamber with each other, and slides inside the sub pressure chamber. Through this communication passage, the first sub Wherein the between the force chamber and the second sub-pressure chamber in which circulating oil.

  According to the present invention, the second valve means including a spool and a pressing means is applied. One end of the spool is housed in a first pressure chamber provided in the valve body, and the other end is housed in a second pressure chamber provided in the valve body. These first pressure chamber and second pressure chamber Oil supply / discharge control for the second hydraulic actuator is performed by moving in the axial direction according to the difference in hydraulic pressure applied to the chamber. The pressing means is interposed between the valve body and the spool, and acts to resist this when the spool moves in one direction due to the hydraulic pressure applied to the first pressure chamber. In the present invention, the operation control means is provided with a piston member and a control spring member. The piston member is provided so that the distal end portion is opposed to the spool in the second pressure chamber, while the proximal end portion is accommodated in the sub pressure chamber provided in the valve body, and the first operation means is operated in one direction. When the pilot pressure in this case is applied to the sub pressure chamber, the tip portion is disposed at a position where it has advanced toward the second pressure chamber, and the advanced position is maintained. The control spring member is interposed between the valve main body and the piston member, and presses in a direction in which the tip end portion of the piston member advances toward the second pressure chamber. This operation control means allows the one-way movement of the spool of the second valve means to the position where the second branch supply passage is opened when the piston member is retracted, while the piston member is arranged at the advanced position. In this case, one-way movement to the position where the second branch supply passage is opened by contacting the spool is prevented. Therefore, the spool of the second valve means sets the stroke amount corresponding to the pilot pressure output from the first operating means by adjusting the diameter of the piston member, the elastic coefficient of the pressing means, and the spring constant of the control spring member. It becomes possible. Accordingly, it is possible to improve the followability of the second hydraulic actuator when the operation amount of the first operation means is reduced in a state where the second operation means and the first operation means are each operated in one direction. become.

  Exemplary embodiments of a drive control apparatus for a hydraulic actuator according to the present invention will be explained below in detail with reference to the accompanying drawings.

  FIG. 1 is a hydraulic circuit diagram showing a hydraulic actuator drive control apparatus according to an embodiment of the present invention. As shown in FIG. 7, the drive control apparatus exemplified here applies to an arm hydraulic cylinder actuator C1 and a bucket hydraulic cylinder actuator C2 of a skid steer loader, and drives these two hydraulic cylinder actuators C1 and C2. It is for performing a desired construction work by controlling. The arm hydraulic cylinder actuator C1 is interposed between the vehicle main body B and the arm AM, and swings the arm AM about the horizontal axis with respect to the vehicle main body B by extending and contracting. Specifically, when the arm hydraulic cylinder actuator C1 is extended, the arm AM lifts (moves in the upward direction) with respect to the vehicle main body B, while when the arm hydraulic cylinder actuator C1 extends, the arm AM with respect to the vehicle main body B is moved. Is provided to move down (move in the downward direction). The bucket hydraulic cylinder actuator C2 is interposed between the arm AM and the bucket BU disposed at the tip thereof, and swings the bucket BU around the horizontal axis with respect to the arm AM by expanding and contracting. is there. Specifically, when the bucket hydraulic cylinder actuator C2 is extended, the bucket BU dumps (moves downward) with respect to the arm AM, while when the bucket hydraulic cylinder actuator C2 is retracted, the bucket BU tilts ( (Moves upward).

  As shown in FIG. 1, the drive control device includes an arm operation valve (first valve means) 10 for controlling oil supply to an arm hydraulic cylinder actuator (first hydraulic actuator) C1, and a bucket hydraulic cylinder actuator. (Second Hydraulic Actuator) A bucket operation valve (second valve means) 20 that controls oil supply to C2 is provided.

  The arm operation valve 10 is operated by a pilot pressure output in response to an operation of an arm operation lever (first operation means) AL. The bucket operation valve 20 is operated by a pilot pressure output in response to the operation of the bucket operation lever (second operation means) BL and a pilot pressure output in response to the operation of the arm operation lever AL. In the present embodiment, as shown in the plan view of FIG. 8, one work machine lever ABL disposed on the right side of the driver seat DS is configured to serve as both the arm operation lever AL and the bucket operation lever BL. is there. More specifically, the work implement lever ABL can be tilted in any direction, functions as the arm operation lever AL when tilted in the front-rear direction, and serves as the bucket operation lever BL when tilted in the left-right direction. Function. When the work implement lever ABL is tilted forward, a pilot pressure corresponding to the arm down is output, and when the work implement lever ABL is tilted rearward, a pilot pressure corresponding to the arm lift is output. When the work implement lever ABL is tilted to the left, a pilot pressure corresponding to the bucket tilt is output, and when the work implement lever ABL is tilted to the right, a pilot pressure corresponding to the bucket dump is output. Further, the work implement lever ABL can be operated in combination. For example, when the work implement lever ABL is tilted to the right rear, two pilot pressures corresponding to the arm lift and the bucket dump can be output. The output pilot pressure is in accordance with the operation amount of the work implement lever ABL.

In the hydraulic circuit of FIG. 1, for convenience, the work implement lever ABL is separately described as an arm operation lever AL and a bucket operation lever BL for each function. Further, when the arm operation lever AL and the bucket operation lever BL are operated with the same operation amount, the pilot pressure output from the bucket operation lever BL is higher than the pilot pressure output from the arm operation lever AL. It is set. Specifically, the pilot pressure of 15 kg / cm ² is output when the operation amount of the arm operation lever AL is maximized, whereas the operation amount of the bucket operation lever BL is maximized. A pilot pressure of 30 kg / cm ² is output.

  As shown in FIG. 1, the arm operation valve 10 includes a supply port 10c and a drain port for two actuator ports 10a and 10b individually connected to two oil chambers C1h and C1r of the arm hydraulic cylinder actuator C1. 10d is switched and connected.

  Specifically, when in the neutral position 10-C shown in FIG. 1, the arm operation valve 10 is in a state where the two actuator ports 10a and 10b, the supply port 10c, and the drain port 10d are closed. When the pilot pressure is supplied from the arm operation lever AL through the lift pilot pressure passage 11 from this state, the arm operation valve 10 is in the first position 10-A, and the supply port 10c and the arm hydraulic cylinder actuator C1 head side. The first actuator port 10a communicating with the oil chamber C1h is connected, and the second actuator port 10b communicating with the rod side oil chamber C1r of the arm hydraulic cylinder actuator C1 and the drain port 10d are connected. On the other hand, when the pilot pressure is supplied from the arm operation lever AL through the down pilot pressure passage 12, the arm operation valve 10 is in the second position 10-B, and the supply port 10c and the second actuator port 10b are connected. In addition, the first actuator port 10a and the drain port 10d are connected.

  The lift pilot pressure passage 11 is connected to the lift pilot pressure output port AL-L of the arm operation lever AL. When the arm operation lever AL is operated in the arm lift direction, a pilot pressure is applied to the arm operation valve 10. Output. The down pilot pressure passage 12 is connected to the down pilot pressure output port AL-D of the arm operation lever AL, and outputs the pilot pressure to the arm operation valve 10 when the arm operation lever AL is operated in the arm down direction. To do.

  Further, the arm operation valve 10 is provided with a load pressure output port 10e for outputting the supply pressure as a load pressure when oil is supplied from the supply port 10c to the arm hydraulic cylinder actuator C1.

  The bucket operation valve 20 includes a supply port 20c, a regeneration supply port 20d, and a drain port 20e with respect to two actuator ports 20a and 20b individually connected to the two oil chambers C2h and C2r of the bucket hydraulic cylinder actuator C2. Are switched and connected.

  Specifically, when in the neutral position 20-C shown in FIG. 1, the bucket operation valve 20 is in a state where the two actuator ports 20a and 20b, the supply port 20c, the regeneration supply port 20d, and the drain port 20e are closed. It is in. When the pilot pressure is supplied through the dump pilot pressure passage 21 from this state, the bucket operation valve 20 is in the first position 20-A or the second position 20-B. When the bucket operating valve 20 is in the first position 20-A, the regeneration supply port 20d and the first actuator port 20a communicating with the head side oil chamber C2h of the bucket hydraulic cylinder actuator C2 are connected, and the bucket The second actuator port 20b that communicates with the rod-side oil chamber C2r of the hydraulic cylinder actuator C2 is connected to the drain port 20e. In this case, the supply port 20c of the bucket operation valve 20 remains closed. When the bucket operation valve 20 is in the second position 20-B, the supply port 20c and the regeneration supply port 20d are connected to the first actuator port 20a, and the second actuator port 20b and the drain port 20e are connected to each other. Connected.

  In contrast, when the pilot pressure is supplied only through the tilt pilot pressure passage 22, the bucket operation valve 20 is in the third position 20-D, and the supply port 20c, the regeneration supply port 20d, and the second actuator port 20b are connected. In addition to being connected, the first actuator port 20a and the drain port 20e are connected.

  The dump pilot pressure passage 21 is connected to the dump pilot pressure output port BL-D of the bucket operation lever BL and the lift pilot pressure output port AL-L of the arm operation lever AL via the high pressure selection valve 21a. When the lever BL is operated in the bucket dump direction and / or when the arm operation lever AL is operated in the arm lift direction, the pilot pressure is output to the bucket operation valve 20. The pilot pressure passage 22 for tilt is connected to the tilt pilot pressure output port BL-T of the bucket operation lever BL, and when the bucket operation lever BL is operated in the bucket tilt direction, the pilot pressure is applied to the bucket operation valve 20. Output.

  Further, the bucket operation valve 20 is provided with a load pressure output port 20f for outputting the supply pressure as a load pressure when oil is supplied from 20c to the bucket hydraulic cylinder actuator C2. The drain port 20 e of the bucket operation valve 20 is connected to the tank T through the drain passage 23.

  As is apparent from FIG. 1, an arm branch supply passage (first branch supply passage) 30A is connected to the supply port 10c of the arm operation valve 10, while the supply port 20c of the bucket operation valve 20 is connected to the supply port 20c. Is connected to a bucket branch supply passage (second branch supply passage) 30B. The arm branch supply passage 30A and the bucket branch supply passage 30B are branched from the main supply passage 30 connected to the discharge port 31a of the hydraulic pump 31, and are provided with individual pressure compensation valves 32A and 32B in the respective paths. ing.

  The pressure compensation valve (hereinafter referred to as “arm pressure compensation valve 32A” when distinguished) is interposed in the arm branch supply passage 30A, and the oil supply pressure by the arm branch supply passage 30A and the load pressure output passage 33 are provided. Is operated by a balance between the load pilot pressure and the pressing force of the setting spring 32Aa. When the load pilot pressure in the load pressure output passage 33 and the pressing force of the setting spring 32Aa are larger than the oil supply pressure, the arm pressure compensation valve 32A is supplied to the arm operation valve 10 from the arm branch supply passage 30A. It functions to reduce the oil flow rate.

  The pressure compensation valve (hereinafter referred to as “bucket pressure compensation valve 32B” when distinguished) is interposed in the bucket branch supply passage 30B, and supplies the oil supply pressure through the bucket branch supply passage 30B and the load pressure output passage 33. Is operated by a balance between the load pilot pressure and the pressing force of the setting spring 32Ba. When the load pilot pressure in the load pressure output passage 33 and the pressing force of the setting spring 32Ba are larger than the oil supply pressure, the bucket pressure compensation valve 32B is supplied to the bucket operation valve 20 from the bucket branch supply passage 30B. It functions to reduce the oil flow rate.

  The load pressure output passage 33 is connected to the load pressure output port 10e of the arm operation valve 10 and the load pressure output port 20f of the bucket operation valve 20 via a high pressure selection valve 33a. The load pressure output passage 33 has a supply pressure of oil supplied from the arm operation valve 10 to the arm hydraulic cylinder actuator C1 and an oil supply pressure supplied from the bucket operation valve 20 to the bucket hydraulic cylinder actuator C2. The higher supply pressure is applied to each of the pressure compensation valves 32A and 32B as the load pilot pressure.

  On the other hand, a regeneration supply passage 40 is connected to the drain port 10 d of the arm operation valve 10. The regeneration supply passage 40 connects between the drain port 10d of the arm operation valve 10 and the regeneration supply port 20d of the bucket operation valve 20, and includes a regeneration control unit 50 in the path. The regeneration control unit 50 is for switching the connection mode between the drain port 10d of the arm operation valve 10 and the regeneration supply port 20d of the bucket operation valve 20, and includes a leveling regeneration valve 51, a regeneration rate increasing valve 52, A regeneration cancellation valve 53 is provided.

  The leveling regeneration valve 51 is interposed in the regeneration supply passage 40 and the regeneration drain passage 41 branched from the regeneration supply passage 40. In the normal state, the leveling regeneration valve 51 shuts off the regeneration supply passage 40 and connects the drain port 10 d of the arm operation valve 10 to the regeneration drain passage 41, while the pilot pressure is supplied via the regeneration pilot pressure passage 24. When supplied, the drain port 10d of the arm operation valve 10 is branched and connected to the regeneration supply passage 40 and the regeneration drain passage 41 at a preset distribution ratio. The regeneration drain passage 41 is connected to the tank T via the pressure control valve 54. The pressure control valve 54 operates by a balance between the pressure of the oil supplied to the regeneration drain passage 41 and the pressure of the oil supplied to the regeneration supply passage 40 + the pressing force of the setting spring 54a. When the pressure of the oil supplied to the regeneration drain passage 41 is larger than the pressure of the oil supplied to the regeneration supply passage 40 + the pressing force of the setting spring 54a, the pressure control valve 54 connects the regeneration drain passage 41 to the tank T. To function. The regeneration pilot pressure passage 24 is connected to the dump pilot pressure output port BL-D of the bucket operation lever BL and the lift pilot pressure output port AL-L of the arm operation lever AL via the high pressure selection valve 24a. The pilot pressure is output to the leveling regeneration valve 51 when the lever BL is operated in the bucket dump direction and / or when the arm operation lever AL is operated in the arm lift direction.

  The regeneration rate increasing valve 52 is connected in parallel with the leveling regeneration valve 51 via the regeneration rate increasing passage 55. The regeneration rate increase valve 52 blocks the regeneration rate increase passage 55 in the normal state, and communicates the regeneration rate increase passage 55 when the pilot pressure is supplied through the regeneration rate increase pilot pressure passage 26. . The regeneration rate increasing pilot pressure passage 26 is connected to the dump pilot pressure output port BL-D of the bucket operation lever BL, and when the bucket operation lever BL is operated in the bucket dump direction, the regeneration rate increasing valve 52 is piloted. Pressure is output.

  The regeneration cancellation valve 53 is interposed in the regeneration cancellation passage 56 branched from a portion of the regeneration supply passage 40 that is located downstream of the joining point of the regeneration rate increasing passage 55. The regeneration cancellation valve 53 blocks the regeneration cancellation passage 56 in a normal state, while the regeneration cancellation passage 56 is supplied when a pilot pressure higher than the pressing force of the setting spring 53a is supplied via the cancellation pilot pressure passage 27. To connect to the tank T. The cancel pilot pressure passage 27 outputs the supply pressure of oil supplied to the regeneration supply port 20d of the bucket operation valve 20 in the regeneration supply passage 40 as a pilot pressure to the regeneration cancel valve 53.

  Furthermore, the drive control device is provided with an operation control means 60. The operation control means 60 includes a piston member 61 and a control spring member 62. The operation control means 60 operates based on the pilot pressure supplied from the open pilot pressure passage 28 and the pilot pressure supplied from the regulation pilot pressure passage 29, and is supplied to the bucket operation valve 20 via the piston member 61. By acting, it has a function of controlling the switching operation. The open pilot pressure passage 28 outputs a pilot pressure so that the piston member 61 is retracted when the bucket operation lever BL is operated in the bucket tilt direction. The regulated pilot pressure passage 29 outputs a pilot pressure so that the piston member 61 moves forward when the arm operation lever AL is operated in the arm lift direction.

  More specifically, when the bucket operation lever BL is operated alone in the bucket dump direction, no pilot pressure is supplied through the regulated pilot pressure passage 29. For this reason, the piston member 61 of the operation control means 60 does not act on the bucket operation valve 20, and the bucket operation valve 20 is switched to the second position 20-B.

  On the other hand, in the state where the arm operation valve 10 is operated in the arm lift direction, the pilot pressure is supplied through the regulated pilot pressure passage 29, so that the piston member 61 of the operation control means 60 is generated by this pilot pressure. Is not arranged at the first position 60-A. When the piston member 61 of the operation control means 60 is not disposed at the first position 60 -A, the state where the pilot pressure is supplied via the restricted pilot pressure passage 29 is maintained. Therefore, the operation control means 60 is held in a state where the piston member 61 has moved forward, and the piston member 61 abuts against the bucket operation valve 20 even when the bucket operation lever BL is operated in the bucket dump direction. Although the movement of the bucket operation valve 20 to the first position 20-A is allowed, the bucket operation valve 20 functions to restrict the movement to the second position 20-B.

  When the bucket operation lever BL is operated in the bucket tilt direction, the piston member 61 of the operation control means 60 is in the first position 60-A by the pilot pressure supplied from the open pilot pressure passage 28, and the regulation pilot pressure passage 29 Is connected to the tank T. Therefore, the pilot pressure is not supplied via the dump pilot pressure passage 21 regardless of the operation of the arm operation valve 10, and the bucket operation valve 20 is moved from the neutral position 20 -C to the third position 20. It will be switched to -D.

  2 to 6 show specific configurations of the bucket operation valve 20 and the operation control means 60. As is clear from these drawings, the bucket operation valve 20 of the present embodiment is arranged in order from the left side of the valve body 200 in the drawing, a drain port 20e, a first actuator port 20a, a communication port 20g, a supply port 20c, A regeneration supply port 20d, a second actuator port 20b, and a drain port 20e are sequentially formed, and a bucket spool 210 is inserted into a spool hole 201 provided to communicate these ports 20e, 20a, 20g, 20c, 20d, 20b, and 20e. It is comprised by arrange | positioning. The communication port 20g communicates with the regeneration supply port 20d through the internal communication passage 20h. The two drain ports 20e are connected to the tank T via the drain passage 23, the first actuator port 20a is connected to the head side oil chamber C2h of the bucket hydraulic cylinder actuator C2, and the supply port The point 20c is connected to the bucket branch supply passage 30B, the regeneration supply port 20d is connected to the drain port 10d of the arm operation valve 10 via the regeneration supply passage 40, and the second actuator port 20b is the bucket. The points connected to the rod-side oil chamber C2r of the hydraulic cylinder actuator C2 are as described above.

  The bucket spool 210 of the bucket operation valve 20 is a cylindrical member having a first annular groove 210a, a second notch 210b, and a third notch 210c on the outer peripheral surface, and is movable along the axial direction. The valve body 200 is fitted into the spool hole 201 so as to be. The first annular groove 210a of the bucket spool 210 is for switching the first actuator port 20a of the valve body 200 between a state communicating with the drain port 20e and a state communicating with the communication port 20g. The second notch 210b is for switching the supply port 20c of the valve body 200 between a state where it communicates with the communication port 20g and a state where it communicates with the regeneration supply port 20d. The third notch 210c switches between the state where the second actuator port 20b communicates with the regeneration supply port 20d and the state where it communicates with the drain port 20e.

  More specifically, when the bucket spool 210 is in the neutral position 20-C shown in FIG. 1, as shown in FIG. 2, the first annular groove 210a opens only to the first actuator port 20a, and the second notch 210b. Opens only to the supply port 20c, and the third notch 210c opens only to the second actuator port 20b.

  From this state, when the bucket spool 210 moves to the right side in the drawing with respect to the valve body 200 and reaches the first position 20-A shown in FIG. 1, as shown in FIGS. 3 and 4, the first annular groove 210a The first actuator port 20a and the communication port 20g communicate with each other, and the second actuator port 20b and the drain port 20e communicate with each other through the third notch 210c. In the first position 20-A shown in FIG. 1, the second notch 210b is still open only to the supply port 20c, as shown in FIGS.

  Further, when the bucket spool 210 moves to the right side and reaches the second position 20-B shown in FIG. 1, as shown in FIG. 5, the first actuator port 20a and the communication port 20g communicate with each other by the first annular groove 210a. In addition, the second actuator port 20b and the drain port 20e communicate with each other through the third cutout 210c, and the supply port 20c and the regeneration supply port 20d communicate with each other through the second cutout 210b.

  On the other hand, when the bucket spool 210 moves from the neutral position 20-C shown in FIG. 1 to the left side in the figure with respect to the valve body 200 and reaches the third position 20-D shown in FIG. 1, as shown in FIG. The first annular groove 210a communicates the first actuator port 20a and the drain port 20e with each other, the second notch 210b communicates with the communication port 20g and the supply port 20c, and the third notch 210c communicates with the second actuator port. 20b and the regeneration supply port 20d communicate with each other.

  As shown in FIG. 2, the bucket spool 210 described above is housed in the respective pressure chambers 202 and 203 at both ends. These pressure chambers 202 and 203 are configured by attaching a cover member 204 to the valve body 200. In FIG. 2, the pressure chamber (hereinafter referred to as “first pressure chamber 202” for distinction) in which the end located on the left side of the bucket spool 210 is accommodated is connected to the dump pilot pressure passage 21. The bucket spool 210 can be moved to the right in the figure by the pilot pressure supplied via the dump pilot pressure passage 21. On the other hand, the pressure chamber (hereinafter referred to as “second pressure chamber 203” when distinguished) in which the end located on the right side of the bucket spool 210 is accommodated is a pilot pressure passage 22 for tilt and an open pilot pressure passage 28. The bucket spool 210 can be moved to the left in the figure by the pilot pressure supplied through these pilot pressure passages 22 and 28.

  The first pressure chamber 202 and the second pressure chamber 203 accommodate pressing means 220 and 230, respectively. The pressing means housed in the first pressure chamber 202 (hereinafter referred to as “first pressing means 220” for distinction) is configured such that the bucket spool 210 is moved to the left in the drawing by the pilot pressure supplied to the second pressure chamber 203. It acts to resist this only when moving. The pressing means housed in the second pressure chamber 203 (hereinafter referred to as “second pressing means 230” when distinguished) is configured such that the bucket spool 210 is moved to the right in the drawing by the pilot pressure supplied to the first pressure chamber 202. It acts to resist this only when moving.

  The first pressing means 220 and the second pressing means 230 include first retainers 221 and 231, second retainers 222 and 232, first spring members 223 and 233, and second spring members 224 and 234, respectively. . The first retainers 221 and 231 are cylindrical members in which end portions of the bucket spool 210 are movably accommodated. When the bucket spool 210 is in the neutral position 20 -C shown in FIG. 1, the first retainers 221 and 231 have respective distal end surfaces abutting against the end surface of the valve body 200, while the proximal end portions are shoulders of the bucket spool 210. The unit 211 is in contact with the portion 211. The second retainers 222 and 232 are cylindrical members in which the first retainers 221 and 231 and the end portions of the bucket spool 210 are movably accommodated. When the bucket spool 210 is in the neutral position 20-C shown in FIG. 1, the second retainers 222 and 232 have respective distal end surfaces abutting against the end surface of the valve body 200, while the proximal end portions are the first retainers 221 and 221. It is arranged at a position separated from the base end face of H.231. The first spring members 223 and 233 are coil springs disposed outside the second retainers 222 and 232. The first spring members 223, 233 are interposed between the valve body 200 and the second retainers 222, 232, and the tip surfaces of the second retainers 222, 232 are always in contact with the end surfaces of the valve body 200. It has a function to hold. The second spring members 224 and 234 are coil springs disposed inside the second retainers 222 and 232, and are configured to have a smaller spring constant than the first spring members 223 and 233. The second spring members 224, 234 are coil springs interposed between the second retainers 222, 232 and the bucket spool 210 via the first retainers 221, 231. The first retainers 221, 231 and the second retainer 222 and 232 are elastically separated from each other.

  On the other hand, the operation control means 60 forms the sub pressure chamber 601 by attaching the sub cover member 600 to the outer surface of the portion of the cover member 204 that constitutes the second pressure chamber 203, and the first pressure chamber 601 has the first pressure chamber 601. The piston body 611 and the control spring member 62 are disposed, and the second piston body 612 is slidably disposed in the piston housing passage 205 provided to communicate between the sub pressure chamber 601 and the second pressure chamber 203. And a sub spring member 613 is interposed between the first piston body 611 and the second piston body 612. The first piston body 611, the second piston body 612, and the sub spring member 613 correspond to the piston member 61 described above.

  The sub pressure chamber 601 is a space connected to the regulated pilot pressure passage 29, and pilot pressure is supplied through the regulated pilot pressure passage 29 when the arm operation valve 10 is operated in the arm lift direction.

  The first piston body 611 is slidably disposed inside the sub pressure chamber 601. The first piston body 611 includes a first sub pressure chamber 601 a that communicates the sub pressure chamber 601 with the restriction pilot pressure passage 29, and a piston housing passage 205. The second sub pressure chamber 601b has a function of being divided. The first piston body 611 has a communication passage 611a that communicates between the first sub pressure chamber 601a and the second sub pressure chamber 601b in the inside thereof, and the first sub pressure is communicated through the communication passage 611a. Oil can be circulated between the chamber 601a and the second sub pressure chamber 601b. The control spring member 62 is interposed between the sub cover member 600 and the first piston body 611 in the first sub pressure chamber 601a, and constantly presses the first piston body 611 in a direction close to the piston housing passage 205. Is.

  The piston accommodating passage 205 is a hole having a diameter smaller than that of the sub pressure chamber 601, and a stopper surface 206 and a piston drain port 207 are provided on the inner peripheral surface thereof. The stopper surface 206 is an annular surface formed by forming the tip portion of the piston accommodating passage 205 close to the second pressure chamber 203 with a small diameter. The piston drain port 207 is an annular recess formed on the base end side in the piston accommodating passage 205, and is connected to the tank T through the drain passage 23.

  The second piston body 612 is a cylindrical member having a distal end with a small diameter. The second piston body 612 has a contact surface 612a between the second piston body 612 and the base end of the large diameter, and a drain on the outer peripheral surface of the base end. It has a notch 612b for use. The contact surface 612a contacts the stopper surface 206 described above when the second piston body 612 is fitted into the piston accommodating passage 205, and faces the second pressure chamber 203 of the second piston body 612 together with the stopper surface 206. It defines the advancing position. In the present embodiment, as shown in FIG. 2, when the second piston body 612 is moved forward most toward the second pressure chamber 203, the tip thereof slightly protrudes into the second pressure chamber 203. A stopper surface 206 and a contact surface 612a are formed. The drain notch 612 b is an annular recess formed in the outer peripheral surface of the second piston body 612. As shown in FIG. 5, the drain notch 612b causes the second piston body 612 to move to the side of the sub pressure chamber 601 by the bucket spool 210 when the bucket operation valve 20 is in the second position 20-B shown in FIG. When the valve is retracted, the piston stays in the piston accommodating passage 205 and does not open to the sub pressure chamber 601. On the other hand, as shown in FIG. 6, when the second piston body 612 is moved back most toward the sub pressure chamber 601, the base end portion opens into the sub pressure chamber 601, and the sub pressure chamber 601 has a first end. The first sub pressure chamber 601a and the piston drain port 207 function to communicate with each other.

  As shown in FIG. 2, the sub spring member 613 is interposed between the first piston body 611 and the second piston body 612 and presses them in directions away from each other. The spring constant of the sub spring member 613 is set to be sufficiently smaller than that of the control spring member 62. As a result, the piston member 61 of the operation control means 60 is in a position where the first piston body 611 is in contact with the cover member 204 by the pressing force of the control spring member 62 in the normal state, and further, by the pressing force of the sub spring member 613, The contact surface 612a of the second piston body 612 is held at a position where it contacts the stopper surface 206 of the valve body 200.

  The operation of the drive control apparatus will be described below with reference to FIGS.

  In this drive control device, when only the arm operation lever AL is operated in the arm lift direction from the neutral positions 10-C and 20-C shown in FIGS. 1 and 2, the pilot pressure corresponding to the operation amount is output as the lift pilot pressure. It is output from the port AL-L and supplied to the arm operation valve 10 via the lift pilot pressure passage 11. Accordingly, as shown in FIG. 1, the arm operation valve 10 is in the first position 10-A, the supply port 10c and the first actuator port 10a are connected, and the second actuator port 10b and the drain port 10d are connected. Connected.

  At the same time, as shown in FIG. 1, the pilot pressure output from the lift pilot pressure output port AL-L of the arm operation lever AL is supplied to the bucket operation valve via the high pressure selection valve 21a and the dump pilot pressure passage 21. 20 first pressure chambers 202 (see FIG. 2). Accordingly, the bucket spool 210 of the bucket operation valve 20 moves to the right from the neutral position 20-C shown in FIG. Here, the pilot pressure output from the lift pilot pressure output port AL-L of the arm operation lever AL is also supplied to the sub pressure chamber 601 (see FIG. 2) of the operation control means 60 through the regulated pilot pressure passage 29. Thus, the second piston body 612 of the piston member 61 is held in a state of moving forward into the second pressure chamber 203 (see FIG. 4). As a result, as shown in FIG. 4, the bucket spool 210 of the bucket operation valve 20 is restricted from moving to the right by the contact of the second piston body 612 of the operation control means 60, and the first spool shown in FIG. The state maintained at the position 20-A, that is, the regeneration supply port 20d is opened while the supply port 20c is closed.

  As a result, as shown in FIG. 1, the oil discharged from the hydraulic pump 31 to the main supply passage 30 is supplied only to the supply port 10c of the arm operation valve 10 through the arm branch supply passage 30A. The oil is supplied to the head side oil chamber C1h through the actuator port 10a. At this time, the oil in the rod side oil chamber C1r of the arm hydraulic cylinder actuator C1 is discharged to the regeneration supply passage 40 through the second actuator port 10b and the drain port 10d. Accordingly, the arm hydraulic cylinder actuator C1 extends and the arm AM of the skid steer loader is driven in the lift direction.

  On the other hand, the pilot pressure output from the lift pilot pressure output port AL-L of the arm operation lever AL is supplied to the leveling regeneration valve 51 of the regeneration control unit 50 via the high pressure selection valve 24a and the regeneration pilot pressure passage 24. . Accordingly, the oil discharged from the arm hydraulic cylinder actuator C1 is supplied to the regeneration supply port 20d of the bucket operation valve 20 via the arm operation valve 10 and the regeneration supply passage 40, and finally is supplied through the first actuator port 20a. To the head side oil chamber C2h of the bucket hydraulic cylinder actuator C2. At this time, the oil in the rod side oil chamber C2r of the bucket hydraulic cylinder actuator C2 is discharged to the drain passage 23 through the second actuator port 20b and the drain port 20e and reaches the tank T. Accordingly, the bucket hydraulic cylinder actuator C2 extends and the bucket BU attached to the tip of the arm AM is driven in the dumping direction.

  As is apparent from the above, when only the arm operation lever AL is operated in the arm lift direction, in the drive control device, the arm hydraulic cylinder actuator C1 is extended to drive the arm AM in the lift direction, and the bucket. The hydraulic cylinder actuator C2 is extended to drive the bucket BU in the dump direction. In this case, since the supply port 20c of the bucket operation valve 20 is kept closed, oil is supplied only to the bucket hydraulic cylinder actuator C2 through the regeneration supply passage 40. That is, when only the arm operation lever AL is operated in the arm lift direction, the oil supply circuit for the two hydraulic cylinder actuators C1 and C2 becomes a series circuit. Of the oil discharged from the arm hydraulic cylinder actuator C1, the flow rate of the oil supplied to the bucket hydraulic cylinder actuator C2 is always a preset diversion ratio by the functions of the leveling regeneration valve 51 and the pressure control valve 54. . As a result, if only the arm operation lever AL is operated in the arm lift direction, so-called leveling control can be performed in which the arm AM is driven in the lift direction while maintaining the posture of the bucket BU.

  When only the arm operation lever AL is operated in the arm down direction from the neutral positions 10-C and 20-C shown in FIGS. 1 and 2, the pilot pressure corresponding to the operation amount is reduced to the pilot pressure passage 12 for down. It is supplied to the arm operation valve 10 through. In this case, no pilot pressure is output to the bucket operation valve 20 or the regeneration control unit 50, and these are kept in the normal state. As a result, when only the arm operating lever AL is operated in the arm down direction, the arm hydraulic cylinder actuator C1 is retracted without operating the bucket hydraulic cylinder actuator C2, and the arm AM is driven in the down direction. The

  Next, when the arm operation lever AL is operated in the arm lift direction from the neutral positions 10-C and 20-C shown in FIGS. 1 and 2, and the bucket operation lever BL is operated in the bucket dump direction, The pilot pressure corresponding to the operation amount is output from the lift pilot pressure output port AL-L and the dump pilot pressure output port BL-D. With respect to the arm operation valve 10, the pilot pressure output from the lift pilot pressure output port AL-L assumes the first position 10-A as before.

  On the other hand, regarding the bucket operation valve 20, the pilot pressure from the dump pilot pressure output port BL-D selected by the high pressure selection valve 21 a is supplied to the first pressure chamber 202 via the dump pilot pressure passage 21. Will be. However, due to the pilot pressure supplied from the lift pilot pressure output port AL-L of the arm operation lever AL to the sub pressure chamber 601 of the operation control means 60 through the restriction pilot pressure passage 29, the second piston body 612 of the piston member 61 is moved to the first position. Since the two pressure chambers 203 are maintained in the advanced state, the bucket spool 210 of the bucket operation valve 20 is maintained at the first position 20-A shown in FIG. As for the leveling regeneration valve 51, the pilot pressure is supplied from the dump pilot pressure output port BL-D selected by the high pressure selection valve 24a via the regeneration pilot pressure passage 24. In this case, the operation is the same as described above. .

  On the other hand, when the bucket operation lever BL is operated in the bucket dump direction, the pilot pressure output from the dump pilot pressure output port BL-D is newly regenerated through the regeneration rate increasing pilot pressure passage 26. 52, the regeneration rate increasing passage 55 is opened. That is, since the oil supply passage to the bucket operation valve 20 through the regeneration rate increasing passage 55 is opened, oil having a flow rate larger than the distribution ratio defined by the leveling regeneration valve 51 passes through the bucket operation valve 20. Is supplied to the hydraulic cylinder actuator C2.

  As a result, when the arm operation lever AL is operated in the arm lift direction and the bucket operation lever BL is operated in the bucket dump direction, the bucket is operated at a higher speed than when the arm operation lever AL is operated alone in the arm lift direction. The BU can be driven in the dump direction. In this case, the regeneration rate increase valve 52 opens according to the operation amount of the bucket operation lever BL, and the opening area of the regeneration rate increase passage 55 increases. Therefore, the driving speed of the bucket BU in the dumping direction also becomes large according to the operation amount of the bucket operation lever BL. However, as described above, the bucket operation valve 20 is maintained at the first position 20-A shown in FIG. 1 and the supply port 20c is kept closed, so that the oil for the two hydraulic cylinder actuators C1 and C2 is maintained. The supply circuit remains as a series circuit. Thus, the arm hydraulic cylinder actuator C1 is driven by the oil discharged from the hydraulic pump 31, and the bucket hydraulic cylinder actuator C2 is driven only by the oil discharged from the arm hydraulic cylinder actuator C1, and is discharged from the hydraulic pump 31. It is not driven by the oil that has been released. As a result, even when the arm operation lever AL and the bucket operation lever BL are combined, the arm AM can be driven in the lift direction at the same speed as when the arm operation lever AL is operated alone.

  Further, the drive speed of the bucket BU in the dumping direction is increased in a state where the operation amount of the arm operation lever AL in the arm lift direction is maximum and the operation amount of the bucket operation lever BL in the bucket dump direction is maximum. For this, the operation amount of the arm operation lever AL may be decreased. That is, when the operation amount of the arm operation lever AL in the arm lift direction is decreased, the pilot pressure from the arm operation lever AL is also decreased, and the bucket operation valve 20 by the piston member 61 of the operation control means 60 based on this pilot pressure. Will be relaxed or lifted. Thus, the bucket operation valve 20 can operate from the first position 20-A to the second position 20-B shown in FIG. 1, and the bucket branch supply passage 30B is opened. Moreover, since the amount of operation of the arm operation lever AL in the arm lift direction is reduced, the amount of oil supplied from the arm branch supply passage 30A to the arm operation valve 10 is reduced. For this reason, in addition to the supply of oil through the regeneration supply passage 40, the oil discharged from the hydraulic pump 31 is supplied directly to the bucket hydraulic cylinder actuator C2 through the bucket branch supply passage 30B. The total flow rate will increase. As a result, the operation amount of the arm operation lever AL is reduced even when the operation amount of the arm operation lever AL in the arm lift direction is the maximum and the operation amount of the bucket operation lever BL in the bucket dump direction is the maximum. By doing so, the drive speed of the bucket BU in the dumping direction can be increased.

  Now, as shown in FIG. 9A, the distance until the end surface of the bucket spool 210 at the neutral position 20-C abuts against the second retainer 232 = a, when the most advanced movement with the end surface of the second retainer 232 occurs. If the distance between the front end surface of the second piston body 612 = b and the distance until the end surface of the second retainer 232 comes into contact with the cover member 204 = c, the operation amount of the arm operation lever AL in the arm lift direction is as follows. When the operation amount is maximum and the operation amount of the bucket operation lever BL in the bucket dump direction is maximum, the bucket spool 210 has a stroke between b and (a + c). In this case, the spring constant of the first spring member 233 = k2, the mounting load of the first spring member 233 = f2, the spring constant of the sub spring member 613 = k3, the mounting load of the sub spring member 613 = f3, the diameter of the bucket spool 210 = D1. (Cross sectional area = A1), Diameter of the second piston body 612 = D2 (Cross sectional area = A2), Pilot pressure supplied from the dump pilot pressure passage 21 to the first pressure chamber 202 = P1, From the regulated pilot pressure passage 29 Assuming that the pilot pressure supplied to the sub pressure chamber 601 is P2, and the arbitrary stroke of the bucket spool 210 is L, the force balance equation can be expressed by the following equation (1).

  P1 × A1 ≦ f2 + k2 × L + f3 + P2 × A2 (1)

  As described above, when the operation amount of the arm operation lever AL is decreased from this state, when the bucket spool 210 is at an arbitrary stroke L, the following expression (2) is established.

  P1 × A1 = f2 + k2 × L + f3 + k3 × (L−b) + P2 × A2 (2)

  From the above equation (2), the stroke L of the bucket spool 210 is represented by the following equation (3).

L = − {A2 / (k2 + k3)} × P2
-(F2 + f3-k3 * b-P1 * A1) / (k2 + k3) (3)

  Here, since k2, k3, f2, f3, b, P1, P2, A1, and A2 are constants, the above equation (3) can be expressed by the following equation (4).

  L = −M × P2 + N (4)

  When the operation amount of the arm operation lever AL in the arm lift direction is decreased, the stroke of the bucket spool 210 is changed from b → (a + c) as shown in FIG. M in the above equation (4) is an inclination when the bucket spool 210 changes. Therefore, for example, if the value of M = A2 / (k2 + k3) is set large, in other words, the second piston body 612 is applied with a large diameter, or the first spring member 233 and the sub spring member 613 have a spring constant. If a smaller one is applied, as shown by the solid line in FIG. 9-2, the driving speed of the bucket BU in the dumping direction can be increased only when the operation amount of the arm operation lever AL in the arm lift direction is sufficiently reduced. Can be increased.

  Conversely, if the value of M = A2 / (k2 + k3) is set small, in other words, the second piston body 612 is applied with a small diameter, or the first spring member 233 and the sub spring member 613 have a spring constant. If a larger one is applied, as indicated by a two-dot chain line in FIG. 9-2, the bucket spool 210 of the bucket operation valve 20 is started from the time when the operation amount of the arm operation lever AL in the arm lift direction is slightly decreased. Starts the stroke, and then the stroke amount of the bucket spool 210 increases as the operation amount decreases. As a result, the driving speed of the bucket BU in the dump direction can be increased in accordance with the operation of the operator, and the operability can be improved in terms of followability.

  As described above, when the operation amount of the bucket operation lever BL in the bucket dump direction is maximized, the operation amount of the arm operation lever AL is decreased, and the bucket operation valve 20 is moved to the first position 20-shown in FIG. In the state of operation from A to the second position 20 -B, the supply pressure of oil to the bucket hydraulic cylinder actuator C 2 is supplied to the regeneration cancel valve 53 through the cancel pilot pressure passage 27. Therefore, when the load pressure of the bucket hydraulic cylinder actuator C2 exceeds the pressing force by the setting spring 53a of the regeneration cancel valve 53, the regeneration cancel valve 53 performs a switching operation and opens the regeneration cancel passage 56.

  As a result, the oil in the regeneration supply passage 40 is discharged to the tank T, and the oil is supplied to the bucket operation valve 20 only through the bucket branch supply passage 30B. That is, when the load pressure of the bucket hydraulic cylinder actuator C2 exceeds a preset value in the series circuit, in other words, when a large driving force is required for the bucket BU, oil is supplied to the two hydraulic cylinder actuators C1 and C2. The circuit becomes a parallel circuit, and a sufficient driving force can be secured for the bucket hydraulic cylinder actuator C2.

  Moreover, the supply pressure of oil supplied to the arm hydraulic cylinder actuator C1 and the supply pressure to the bucket hydraulic cylinder actuator C2 are supplied to the arm branch supply passage 30A and the bucket branch supply passage 30B branched from the main supply passage 30. Pressure compensation valves 32A and 32B that operate based on the higher supply pressure of the oil supply pressure are provided. Therefore, the pressure difference between the upstream side and the downstream side of the arm operation valve 10 is controlled to be the same value as the pressure difference between the upstream side and the downstream side of the bucket operation valve 20, and the two hydraulic cylinder actuators are controlled. Regardless of the load pressure of C1 and C2, a flow rate proportional to the opening area of the arm operation valve 10 and the opening area of the bucket operation valve 20 is ensured. As a result, a situation in which oil is supplied to the hydraulic cylinder actuator having a large load pressure after the oil is supplied to the hydraulic cylinder actuator having a low load pressure is not caused.

  Next, when the bucket operation lever BL is operated in the bucket tilt direction from the neutral positions 10-C and 20-C shown in FIG. 1, the pilot output from the tilt pilot pressure output port BL-T of the bucket operation lever BL. The pressure is supplied to the second pressure chamber 203 of the bucket operating valve 20 through the pilot pilot pressure passage 22 for tilting and to the operation control means 60 through the open pilot pressure passage 28. When the pilot pressure is supplied to the operation control means 60 through the open pilot pressure passage 28, the piston member 61 is in the first position 60-A, and the sub pressure chamber 601 is in the second piston as shown in FIG. The drain notch 612 b of the body 612 is connected to the piston drain port 207, and the oil in the sub pressure chamber 601 is discharged to the tank T through the drain passage 23. Therefore, when the bucket operation lever BL is operated in the bucket tilt direction, the sub pressure chamber 601 of the operation control means 60 becomes the tank pressure regardless of the operation of the arm operation lever AL, and the bucket spool 210 is shown in FIG. It becomes the 3rd position 20-D shown. As a result, as shown in FIG. 6, oil is supplied to the rod-side oil chamber C2r of the bucket hydraulic cylinder actuator C2 via the second actuator port 20b, and the bucket BU is driven in the tilt direction with respect to the arm AM. .

  By the way, in the present embodiment, as described above, the operation lever having the only work machine lever ABL is applied, and the operation direction is changed so as to function as the arm operation lever AL and the bucket operation lever BL. I have to. Moreover, the work machine lever ABL is arranged on the right side of the driver seat DS. Therefore, for example, when an operator seated in the driver's seat DS tries to drive the arm AM in the lift direction and tilts the work implement lever ABL backward, the work implement lever ABL may also tilt in a direction approaching the operator. There is. That is, when the work implement lever ABL is tilted backward to drive the arm AM in the lift direction, the work implement lever ABL may be momentarily tilted also in the bucket tilt direction.

  Here, as described above, in the present embodiment, when the arm operation lever AL is operated alone in the arm lift direction, the bucket operation valve 20 is switched to the first position 20-A as shown in FIG. In addition, the piston member 61 of the operation control means 60 regulates the movement of the bucket spool 210, so that the oil supply circuit for the two hydraulic cylinder actuators C1 and C2 is maintained as a series circuit, and leveling control is performed. I am doing so.

  Therefore, when the bucket operation lever BL is operated in the bucket tilt direction in a state where the arm operation lever AL is operated alone in the arm lift direction, it is output from the tilt pilot pressure output port BL-T of the bucket operation lever BL. The pilot pressure is supplied to the second pressure chamber 203 of the bucket operation valve 20 and acts in a direction in which the piston member 61 is retracted (rightward in FIG. 4), in other words, in a direction in which the leveling control is canceled.

  However, in the present embodiment, as the piston member 61 of the operation control means 60, the first piston body 611 and the control spring member 62 are disposed in the sub pressure chamber 601, and the sub pressure chamber 601 and the second pressure chamber 203 are provided. A second piston body 612 is slidably disposed in a piston housing passage 205 provided to communicate with each other, and a sub spring member 613 is interposed between the first piston body 611 and the second piston body 612. Apply. In addition, in order to move the first piston body 611 in the sub pressure chamber 601, oil is provided between the first sub pressure chamber 601a and the second sub pressure chamber 601b via the communication passage 611a formed in the first piston body 611. Need to be distributed. Therefore, when the arm operation lever AL is operated alone in the arm lift direction, the bucket operation lever BL is instantaneously operated in the bucket tilt direction, and the pilot pressure acting on the second pressure chamber 203 of the bucket operation valve 20 is operated. Thus, even if the second piston body 612 is retracted, the first piston body 611 functions as a shock absorber due to the passage resistance of the oil flowing through the communication passage 611a and prevents further movement of the second piston body 612. As a result, the drain notch 612b of the second piston body 612 does not cause the sub pressure chamber 601 and the piston drain port 207 to communicate with each other, the series circuit is secured, and the leveling control is continued. Will be implemented.

  When the bucket operation lever BL is continuously operated in the bucket tilt direction to drive the bucket BU in the tilt direction, the pilot pressure is gradually supplied to the second pressure chamber 203 of the bucket operation valve 20. Will be. For this reason, oil will appropriately flow between the first sub pressure chamber 601a and the second sub pressure chamber 601b through the communication passage 611a, and the second piston body 612 contracts together with the first piston body 611. The oil in the sub pressure chamber 601 is drained into the tank T by the notch 612b.

  In the above-described embodiment, the piston member 61 of the operation control means 60 is exemplified by the first piston body 611, the second piston body 612, and the sub spring member 613, but is not necessarily limited thereto. For example, as shown in the modification of FIG. 10, only the piston member 61 corresponding to the second piston body 612 of the embodiment is applied, and the sub spring member 613 of the embodiment is caused to act as the control spring member 62. Anyway. Also in this modification, since the above equations (1) to (4) are established, the arm operation can be performed by appropriately changing the diameter of the second piston body 612 and the spring constants of the first spring member 233 and the sub spring member 613. The operation of the bucket BU when the operation amount of the arm operation lever AL is decreased from the state where the operation amount of the lever AL in the arm lift direction is the maximum and the operation amount of the bucket operation lever BL in the bucket dump direction is the maximum. It becomes possible to control the operation timing. In addition, in the modification of FIG. 10, about the structure similar to embodiment, the same code | symbol is attached | subjected and each detailed description is abbreviate | omitted.

1 is a hydraulic circuit diagram showing a drive control apparatus for a hydraulic actuator according to an embodiment of the present invention. FIG. 2 is a hydraulic circuit diagram showing a specific configuration of a bucket operation valve and operation control means in a neutral position in the hydraulic actuator drive control device shown in FIG. 1. FIG. 2 is a hydraulic circuit diagram showing a specific configuration of a bucket operation valve and operation control means in a first position in the hydraulic actuator drive control device shown in FIG. 1. FIG. 2 is a hydraulic circuit diagram showing a specific configuration of a bucket operation valve and operation control means in a first position in the hydraulic actuator drive control device shown in FIG. 1. FIG. 2 is a hydraulic circuit diagram showing a specific configuration of a bucket operation valve and operation control means in a second position in the hydraulic actuator drive control device shown in FIG. 1. FIG. 5 is a hydraulic circuit diagram showing a specific configuration of a bucket operation valve and operation control means in a third position in the hydraulic actuator drive control device shown in FIG. 1. It is a conceptual diagram of the construction machine carrying the hydraulic actuator used as the application object of the drive control apparatus shown in FIG. It is a top view which shows the driver's seat of the construction machine shown in FIG. It is the figure which showed typically the principal part of the hydraulic circuit diagram shown in FIG. It is a graph which shows the relationship between the pilot pressure of an arm lift direction, and the stroke of a bucket spool. It is a hydraulic circuit diagram which shows the modification of the drive control apparatus shown in FIG.

Explanation of symbols

10 Arm operation valve (first valve means)
20 Bucket operation valve (second valve means)
30 Main supply passage 30A Branch supply passage for arm (first branch supply passage)
30B Bucket branch supply passage (second branch supply passage)
Reference Signs List 31 hydraulic pump 40 regeneration supply passage 41 regeneration drain passage 50 regeneration control unit 51 leveling regeneration valve 52 regeneration rate increase valve 53 regeneration cancel valve 54 pressure control valve 55 regeneration rate increase passage 56 regeneration cancel passage 60 operation control means 61 piston member 62 control Spring member 200 Valve body 201 Spool hole 202 First pressure chamber 203 Second pressure chamber 204 Cover member 205 Piston accommodating passage 207 Piston drain port 210 Bucket spool 220, 230 Pressing means 221, 231 First retainer 222, 232 Second retainer 223 , 233 First spring member 224, 234 Second spring member 600 Sub cover member 601 Sub pressure chamber 601a First sub pressure chamber 601b Second sub pressure chamber 611 First piston body 611a Communication passage 612 Second piston body 6 3 Sabubane member AL arm operating lever (first operation unit)
BL Bucket operation lever (second operation means)
C1 hydraulic cylinder actuator for arm (first hydraulic actuator)
Hydraulic cylinder actuator for C2 bucket (second hydraulic actuator)

Claims (3)

A first hydraulic actuator in which oil is supplied and discharged via a first valve means;
A second hydraulic actuator that is controlled to supply and discharge oil via a second valve means;
A first branch supply passage branched from a main supply passage connected to a discharge port of the hydraulic pump, connected to the first valve means, and a second branch supply passage connected to the second valve means;
A regeneration supply passage connecting between the first valve means and the second valve means, and capable of supplying oil discharged from the first hydraulic actuator to the second hydraulic actuator;
First operating means provided corresponding to the first valve means;
Second operating means provided corresponding to the second valve means;
Operation control means for controlling the switching operation by acting on the second valve means when the first operation means is operated in one direction, and each of the first operation means and the second operation means in one direction When the operation control means acts on the second valve means, the second valve means closes the second branch supply passage and opens the regeneration supply passage. When the amount of operation of the first operating means in one direction is reduced while the second operating means is operated in one direction, the second valve actuator is connected to the second hydraulic actuator through the second branch supply passage. A hydraulic actuator drive control device configured to switch to a position to supply oil to
The second valve means includes
One end is accommodated in a first pressure chamber provided in the valve body, and the other end is accommodated in a second pressure chamber provided in the valve body. In addition to the first pressure chamber and the second pressure chamber, A spool for performing oil supply / discharge control with respect to the second hydraulic actuator by moving in the axial direction according to the difference in hydraulic pressure,
A pressing means interposed between the valve body and the spool and acting to resist the spool when it moves in one direction by the hydraulic pressure applied to the first pressure chamber. Yes,
Each of the first operation means and the second operation means outputs a pilot pressure corresponding to an individual operation direction and an individual operation amount,
The operation control means includes
The distal end portion is provided so as to face the spool in the second pressure chamber, while the proximal end portion is accommodated in the sub pressure chamber provided in the valve body, and the first operation means is operated in one direction. A piston member that is disposed at a position where a tip portion is advanced toward the second pressure chamber when the pilot pressure is applied to the sub pressure chamber, and maintains the advanced position;
A control spring member that is interposed between the valve body and the piston member and presses in a direction in which a tip portion of the piston member advances toward the second pressure chamber, and when the piston member is retracted The spool of the second valve means is allowed to move in one direction to the position where the second branch supply passage is opened. On the other hand, when the piston member is disposed at the advanced position, the spool comes into contact with the spool. A drive control device for a hydraulic actuator, which prevents movement in one direction to a position where the two-branch supply passage is opened. The pressing means is
A retainer disposed between the valve body and the spool;
A first spring member interposed between the retainer and the valve body;
A second spring member interposed between the spool and the retainer;
The hydraulic actuator drive control device according to claim 1, wherein the first spring member and the second spring member have different spring constants. The piston member is
The sub pressure chamber is divided into a first sub pressure chamber and a second sub pressure chamber so as to be slidable inside the sub pressure chamber, and a control spring member is interposed between the sub pressure chamber and the valve body. A first piston body;
A second piston body arranged in a manner to move forward and backward with respect to the second pressure chamber, and capable of coming into contact with the spool of the second valve means when moved forward;
A sub-spring member interposed between the first piston body and the second piston body and pressing both in a direction away from each other, wherein the first piston body includes the first sub-pressure chamber and the second sub-pressure chamber. A communication passage communicating with each other, and when sliding inside the sub pressure chamber, oil is circulated between the first sub pressure chamber and the second sub pressure chamber through the communication passage. The drive control apparatus for a hydraulic actuator according to claim 1.

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