JP2015048857A - Hydraulic circuit of construction machine, and construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic circuit including a regeneration circuit (regeneration oil passage, regeneration valve and regeneration release valve) reduced in pressure loss of a pressure oil generated in regenerating a return oil, and to provide a construction machine having the hydraulic circuit .SOLUTION: A hydraulic circuit of a construction machine operating an attachment by driving a hydraulic cylinder 12c, has a regeneration oil passage 21 for regenerating a return oil from the hydraulic cylinder 12c, a regeneration valve 22 disposed in the regeneration oil passage 21 for controlling circulation of the return oil, and a regeneration release valve 23 disposed at the downstream side of the regeneration valve 22 and switching a return oil supply destination, and the regeneration oil passage 21 is mounted on the attachment 12c.

Description

  The present invention relates to a hydraulic circuit of a construction machine and a construction machine.

  Some construction machines supply pressure oil to expand and contract a hydraulic cylinder, and the attachment is driven by the expanded and contracted hydraulic cylinder. Some hydraulic circuits of construction machines supply (regenerate) so-called return oil from the hydraulic cylinder to the hydraulic cylinder again in order to improve the operability of the attachment.

  Patent Document 1 discloses a technique relating to a regeneration hydraulic circuit (hydraulic circuit) that selectively regenerates return oil from a hydraulic cylinder using a regeneration function valve (regeneration valve).

Japanese Patent Laid-Open No. 06-117415

  In the technique disclosed in Patent Document 1, when the return oil is regenerated when the load on the attachment is small, it is necessary to reduce the CT opening of the control valve and increase the pressure of the pressure oil to be regenerated. For this reason, in the technique disclosed in Patent Document 1, the pressure loss of the pressure oil may increase during regeneration.

  Further, in the technique disclosed in Patent Document 1, when the construction machine is excavated and is not regenerated, for example, the pressure oil (returned oil) is discharged through the CT opening of the control valve. For this reason, in the technique disclosed in Patent Document 1, the back pressure of the hydraulic cylinder increases, the pressure loss of the pressure oil passing through the control valve increases, and the excavation performance of the construction machine (the driving force of the hydraulic cylinder, Drive speed, etc.) may decrease.

  In the conventional technique of regenerating the return oil via the control valve, energy loss occurs at the opening of the control valve. Also, in the conventional technology that regenerates the return oil via the control valve, the regeneration oil path (the oil path through which the regenerated pressure oil flows) becomes longer according to the separation distance between the control valve and the hydraulic cylinder. Increased oil pressure loss.

  The present invention has been made under such circumstances, and is a construction machine or a hydraulic circuit of a construction machine in which a regeneration oil passage is mounted in the vicinity of a hydraulic cylinder, and includes a regeneration valve and a regeneration release valve disposed in the regeneration oil passage. An object of the present invention is to provide a construction machine or a hydraulic circuit that regenerates return oil from a hydraulic cylinder. That is, the present invention includes a hydraulic circuit having a regeneration circuit (regeneration oil passage, regeneration valve, and regeneration release valve) or a hydraulic circuit thereof that can reduce the pressure loss of the pressure oil generated when the return oil is regenerated. The purpose is to provide construction machinery.

  According to one aspect of the present invention, there is provided a hydraulic circuit for a construction machine that drives a hydraulic cylinder to operate an attachment, the regeneration oil path that regenerates return oil from the hydraulic cylinder, and the hydraulic oil circuit that is disposed in the regeneration oil path. A regeneration valve that controls the flow of the return oil, and a regeneration release valve that is disposed downstream of the regeneration valve and switches a supply destination of the return oil, and the regeneration oil path is mounted on the attachment A hydraulic circuit for a construction machine is provided. The regeneration release valve may be a hydraulic circuit that switches between regenerating the return oil or discharging it to the tank according to the load of the attachment. The regenerative oil passage is arranged side by side with the hydraulic cylinder, and the return oil flowing out from the rod side of the hydraulic cylinder is supplied to the bottom side of the hydraulic cylinder. Good. The regeneration release valve may be a hydraulic circuit that switches a supply destination of the return oil using a pressure of hydraulic oil supplied from a hydraulic pump to a bottom side of the hydraulic cylinder.

  Moreover, according to the other aspect of this invention, a construction machine provided with any one of said hydraulic circuit is provided.

  According to the construction machine or the hydraulic circuit of the construction machine according to the present invention, the return oil from the hydraulic cylinder can be regenerated using the regeneration oil passage, the regeneration valve, and the regeneration release valve mounted in the vicinity of the hydraulic cylinder.

1 is a schematic external view showing an example of a construction machine according to an embodiment of the present invention. It is a general | schematic external view explaining an example of arrangement | positioning of the reproduction | regeneration circuit of the construction machine which concerns on embodiment of this invention. 1 is a schematic hydraulic circuit diagram illustrating an example of a hydraulic circuit of a construction machine according to an embodiment of the present invention. It is explanatory drawing explaining an example of the regeneration cancellation | release valve used for the regeneration circuit of the construction machine which concerns on embodiment of this invention. It is a schematic hydraulic circuit diagram which shows the other example (comparative example) of the hydraulic circuit of a construction machine.

  Non-limiting exemplary embodiments of the present invention will be described with reference to the accompanying drawings. In the description of all attached drawings, the same or corresponding members or parts are denoted by the same or corresponding reference numerals, and redundant description is omitted. Also, the drawings are not intended to show the relative ratio between members or parts. Accordingly, specific dimensions can be determined by one skilled in the art in light of the following non-limiting embodiments.

  Hereinafter, the present invention will be described using the construction machine 100 according to the embodiment. In addition to the present embodiment, the present invention is a hydraulic circuit or machine, device, or system that reuses return oil from a hydraulic cylinder using a regeneration valve (for example, a switching valve) and a regeneration release valve. Any of them can be used. Construction machines that can use the present invention include hydraulic excavators, crane trucks, bulldozers, wheel loaders and dump trucks, pile driving machines, pile removers, water jets, mud drainage treatment equipment, grout mixers, deep Includes foundation and drilling machines.

  The present invention will be described in the following order using the construction machine 100 according to the embodiment.

1. Construction machinery Hydraulic circuit of construction machine [1. Construction machinery]
A schematic configuration of the construction machine 100 according to the embodiment of the present invention will be described with reference to FIGS. 1 and 2. Here, FIG. 1 is a schematic external view showing an example of the construction machine 100 according to the present embodiment. FIG. 2 is an example of the arrangement of the regeneration circuit 20 of the construction machine 100 and is an enlarged view for explaining a region Ra in FIG.

  As shown in FIG. 1, the construction machine 100 according to the present embodiment includes an upper swing body 10Up on which a cab (cab) 10Cb is mounted, and a lower traveling body 10Dw that moves the construction machine 100 using wheels and the like. Prepare. Further, the construction machine 100 includes, as an attachment, a boom 11 whose base end is pivotally supported by the upper swing body 10Up, an arm 12 pivotally supported by the distal end of the boom 11, and a bucket pivotally supported by the distal end of the arm 12. 13. Furthermore, the construction machine 100 includes, as hydraulic cylinders, a boom cylinder 11c that drives the boom 11, an arm cylinder 12c that drives the arm 12, and a bucket cylinder 13c that drives the bucket 13.

  In addition, the construction machine which can use this invention may use attachments other than said boom 11, the arm 12, and the bucket 13 as an attachment attached.

  The construction machine 100 according to this embodiment extends and contracts the boom cylinder 11c in the longitudinal direction by supplying hydraulic oil (pressure oil) to the boom cylinder 11c. At this time, the boom 11 is driven in the vertical direction in front of and above the cab 10Cb by expansion and contraction of the boom cylinder 11c. Further, the construction machine 100 controls the boom direction control valve in accordance with the operation amount (and operation direction) of an operation lever (for example, Lvr in FIG. 3 described later) of an operator (driver, operator) in the cabin of the cab 10Cb. The hydraulic oil supplied to the boom cylinder 11c is controlled. As a result, the construction machine 100 can perform a desired work according to the operation amount of the operation lever of the operator.

  As in the case of the boom 11, the construction machine 100 drives the arm 12 and the bucket 13 in front of and / or above the cab 10Cb by expansion and contraction of the arm cylinder 12c and the bucket cylinder 13c. As in the case of the boom cylinder 11c, the construction machine 100 controls the hydraulic oil supplied to the arm cylinder 12c and the bucket cylinder 13c by the arm direction control valve and the bucket direction control valve. Moreover, the construction machine 100 according to the present embodiment uses the wheels of the lower traveling body 10Dw and the turning motor 14m to run the construction machine 100 (moving back and forth and from side to side) and rotate the upper turning body 10Up (turning operation). .

  The construction machine 100 according to the present invention uses the regeneration circuit 20 (FIG. 2) to re-supply the return oil from the hydraulic cylinder to the hydraulic cylinder (hereinafter referred to as “regeneration”). As shown in FIG. 2, the construction machine 100 supplies pressure oil to the arm cylinder 12c (the bottom 12cb or the rod 12cr thereof) via an oil passage (P-Cb or P-Cr). In the present embodiment, the construction machine 100 regenerates the return oil from the arm cylinder 12c (the rod side in the present embodiment) using the regeneration circuit 20 mounted on the boom 11. In the construction machine to which the present invention can be used, the mounting position (or arrangement position) of the regeneration circuit 20 is appropriately set according to the attachment to be attached and the hydraulic cylinder to which the return oil to be regenerated is supplied.

  The regeneration circuit 20 is a circuit that regenerates the return oil from the hydraulic cylinder (in this embodiment, the arm cylinder 12c). In this embodiment, the regeneration circuit 20 includes a regeneration oil passage 21, a regeneration valve 22, and a regeneration release valve 23. Further, the reproduction circuit 20 is mounted on an attachment (the boom 11 in the present embodiment). Note that the reproduction circuit 20 may be arranged near or inside the attachment.

  The regeneration oil passage 21 is an oil passage through which return oil from the hydraulic cylinder is circulated. In this embodiment, the regenerated oil passage 21 is arranged alongside the arm cylinder 12c (hydraulic cylinder) (FIG. 2). The reclaimed oil passage 21 is mounted on the boom 11 (attachment). Further, the regenerated oil passage 21 supplies the return oil flowing out from the rod side (12cr in the figure) of the arm cylinder 12c to the bottom side (12cb in the figure) of the arm cylinder 12c.

  As a result, the construction machine 100 according to the present invention does not need to regenerate the return oil via a control valve or the like, and therefore uses the reclaimed oil path 21 and the oil path (oil path through which the regenerated pressure oil flows). Can be shortened, and the pressure loss of the pressure oil (return oil) can be reduced.

  The regeneration valve 22 is a valve that controls whether or not to regenerate the return oil from the hydraulic cylinder. As shown in FIG. 2, the regeneration valve 22 is disposed on the upstream side of the regeneration oil passage 21. The regeneration valve 22 controls the amount of the return oil that has flowed out from the rod side of the arm cylinder 12c to the bottom side by adjusting the opening area according to the operating state of the arm operation lever, for example. As the regeneration valve 22, for example, a switching valve, an electromagnetic valve, or the like may be used.

  Thereby, the construction machine 100 according to the present invention can control whether or not to regenerate the return oil in the vicinity of the hydraulic cylinder (the arm cylinder 12c in the present embodiment) and the amount of regeneration using the regeneration valve 22. it can. For this reason, the construction machine 100 can shorten the oil passage (the oil passage through which the regenerated pressure oil flows). Moreover, since the construction machine 100 can shorten the oil passage (the oil passage through which the regenerated pressure oil flows), the pressure loss of the pressure oil (return oil) can be reduced.

  The regeneration cancellation valve 23 is a valve that switches the supply destination of return oil via the regeneration valve 22. As shown in FIG. 2, the regeneration cancellation valve 23 is disposed on the downstream side of the regeneration oil passage 21. In the present embodiment, the regeneration release valve 23 switches whether to regenerate the return oil or discharge it to the tank according to the load of the arm 12 (attachment).

  Thereby, the construction machine 100 according to the present invention can control whether to regenerate the return oil that has passed through the regeneration valve 22 by using the regeneration cancellation valve 23. Moreover, the construction machine 100 according to the present invention can control the operation of regenerating the return oil according to the work state or work operation (for example, excavation operation) of the construction machine.

  Specifically, in this embodiment, the regeneration release valve 23 uses the pressure of hydraulic oil supplied from the hydraulic pump Pmp (FIG. 3 to be described later) to the bottom side of the arm cylinder 12c (hydraulic cylinder) to return oil. Switch the supply destination. When the pressure on the bottom side of the arm cylinder 12c is low, the regeneration release valve 23 closes the opening, for example, to regenerate the return oil. Further, when the pressure on the bottom side of the arm cylinder 12c is high, the regeneration release valve 23 opens an opening and discharges the return oil downstream (for example, a hydraulic oil tank) so as not to regenerate the return oil, for example. .

  Note that the opening of the regeneration release valve 23 may be controlled in accordance with a command of a controller mounted in advance on the construction machine 100.

  An example of the regeneration release valve used in the regeneration circuit of the construction machine according to the present invention will be described with reference to FIG. The regeneration release valve according to the present invention is not limited to that shown in FIG.

  The regeneration circuit 20 (FIG. 4) according to the present embodiment is mounted on the boom 11 as shown in FIG. Further, the regeneration release valve 23 of the regeneration circuit 20 according to the present embodiment is disposed on the bottom side 12cb of the arm cylinder 12c as shown in FIG. Furthermore, the regeneration circuit 20 according to the present embodiment flows hydraulic oil (Vc-Cy in the drawing) supplied from the direction control valve Vc (FIG. 3 to be described later) into the bottom side of the arm cylinder 12c.

  As shown in FIG. 4, the regeneration circuit 20 includes a spool 30 </ b> B that controls the flow direction of pressure oil (switches the supply destination) inside the regeneration release valve 23. Further, the regeneration circuit 20 includes therein a throttle 24 and a check valve 25 that control the flow (pressure, flow rate, etc.) of pressure oil flowing from the rod side of the arm cylinder 12c.

  When regenerating the return oil, the regeneration circuit 20 re-supplys the pressure oil (Cy1-R in the figure) flowing out from the rod side of the arm cylinder 12c to the bottom side of the arm cylinder 12c (Cy-B in the figure). . At this time, the regeneration circuit 20 uses the throttle 24 and the check valve 25 to control the flow rate and pressure of the pressure oil to be resupplied to the bottom side of the arm cylinder 12c.

  Further, the regeneration circuit 20 uses the pressure input to one end of the spool 30B (regeneration release valve 23) (pressure of the pressure oil on the bottom side of the arm cylinder 12c) when the return oil is not regenerated. Move in the direction and change its opening shape. As a result, the regeneration circuit 20 uses the regeneration release valve 23 to cause the pressure oil (Cy2-R in the figure) flowing out from the rod side of the arm cylinder 12c to pass through the opening formed by the moved spool 30B. The oil can be discharged into the hydraulic oil tank (Cy-T in the figure).

[2. Hydraulic circuit of construction machinery]
The hydraulic circuit 100C of the construction machine 100 according to the embodiment of the present invention will be described with reference to FIG. FIG. 3 is a schematic hydraulic circuit diagram showing an example of the hydraulic circuit 100C according to the present embodiment.

  In addition, the continuous line described in FIG. 3 shows an oil path (pressure oil path). A dotted line shows the oil path of a pilot circuit (remote control circuit). Further, in FIG. 3, the reproducing circuit 20 is mainly shown to explain the present invention, and other parts (for example, an electric control system of the controller) are omitted. Furthermore, the present invention can be used in any circuit other than the hydraulic circuit 100C shown in FIG. 3 as long as it uses the regeneration circuit 20 to regenerate the return oil from the hydraulic cylinder.

  As shown in FIG. 3, the hydraulic circuit 100C includes a hydraulic pump Pmp that discharges pressure oil (hydraulic oil), a direction control valve Vc that is supplied with the pressure oil discharged from the hydraulic pump Pmp, and a direction control valve Vc. And a hydraulic cylinder Cy arranged on the downstream side. The hydraulic circuit 100C includes a pilot pump Pmp-PL that generates a pilot pressure that is input to the control port of the directional control valve Vc.

  Furthermore, the hydraulic circuit 100 </ b> C according to the present invention further includes a regeneration circuit 20 including a regeneration oil passage 21, a regeneration valve 22, and a regeneration release valve 23. In addition, the hydraulic circuit 100C according to the present invention includes a holding valve Vsp between the rod side of the hydraulic cylinder Cy and the regeneration valve 22. The hydraulic circuit 100C may have a configuration in which the holding valve Vsp is omitted by making the regeneration valve 22 have a structure with less leakage of hydraulic oil (providing a function as a holding valve).

  The hydraulic circuit 100C according to the present embodiment controls the operation of supplying (inputting) the pressure oil discharged from the hydraulic pump Pmp to the direction control valve Vc by controlling the operation of the hydraulic pump Pmp. Further, the hydraulic circuit 100C controls the operation of the pilot pump Pmp-PL to control the operation of the direction control valve Vc, so that the hydraulic cylinder Cy (11c, 12c and 13c in FIG. 1) from the direction control valve Vc, and The flow rate and direction of hydraulic oil (pressure oil) supplied (inflow) to the hydraulic motor (14m in FIG. 1) are controlled. Further, the hydraulic circuit 100C uses the regeneration circuit 20 to control the operation of regenerating the return oil from the hydraulic cylinder Cy.

  The hydraulic circuit 100C is an oil passage between the regeneration valve 22 and the hydraulic cylinder Cy, and restricts the flow (pressure, flow rate, etc.) of the regenerated pressure oil (return oil) and the regenerated pressure. It may further include a check valve (check valve) 25 that restricts the flow of oil in one direction (the direction of flowing into the bottom side). Thereby, the hydraulic circuit 100C can control the pressure of the return oil to be regenerated and prevent the backflow of the pressure oil.

  The hydraulic pump Pmp discharges pressure oil (operating oil) flowing into the hydraulic cylinder Cy. The hydraulic pump Pmp may be configured to be mechanically connected to an output shaft of a power source (such as a prime mover, an engine, and a motor) (not shown) and discharge pressure oil using the power of the power source.

  The direction control valve Vc controls the flow rate and flow direction of the pressure oil (hydraulic oil) supplied to the boom cylinder 11c, the arm cylinder 12c or the bucket cylinder 13c, or the turning motor 14c. Further, the direction control valve Vc controls the flow rate and flow direction of the pressure oil supplied (inflowed) to the hydraulic cylinder (or hydraulic motor) based on the pilot pressure (remote control pressure) input to the control port. In FIG. 3, a plurality of directional control valves corresponding to each hydraulic cylinder are omitted, and only one directional control valve is illustrated. In FIG. 3, the shape of the spool of the direction control valve is omitted.

  The hydraulic cylinder Cy drives an attachment (such as 11 in FIG. 1) by its expansion and contraction operation. The hydraulic cylinder Cy expands and contracts in the longitudinal direction using the pressure oil (hydraulic oil) supplied from the direction control valve Vc. As shown in FIG. 1, in the construction machine 100 of the present embodiment, the hydraulic cylinder Cy includes a boom cylinder 11 c that drives the boom 11, an arm cylinder 12 c that drives the arm 12, and a bucket cylinder 13 c that drives the bucket 13. Is provided.

  Further, as shown in FIG. 3, the hydraulic cylinder Cy is disposed downstream of the directional control valve Vc and between an oil passage Ocb connected to the bottom side and an oil passage Ocr connected to the rod side ( Is included).

  The hydraulic cylinder Cy can be composed of a cylinder container and a piston. The hydraulic cylinder Cy is supplied with hydraulic oil (pressure oil) to a bottom side (head side, push side) chamber and a rod side (pull side) chamber. When hydraulic oil is supplied to the bottom side, the hydraulic cylinder Cy moves a built-in piston or the like in the pushing direction and extends in the longitudinal direction. Further, when hydraulic oil is supplied to the rod side, the hydraulic cylinder Cy moves the built-in piston or the like in the pulling direction and contracts in the longitudinal direction.

  As shown in FIG. 3, the regeneration circuit 20 according to the present invention includes a regeneration oil passage 21, a regeneration valve 22, and a regeneration release valve 23, and flows out from the rod side of the hydraulic cylinder (arm cylinder 12c in this embodiment). Re-supply the return oil to the bottom side. The configurations of the regeneration oil passage 21, the regeneration valve 22, and the regeneration cancellation valve 23 are the same as those described in [1. Since the configuration is the same as that described in [Construction Machine], the description is omitted.

  The hydraulic circuit 100C of the construction machine 100 is configured to be connected to a controller (not shown) for controlling the operation of the construction machine 100. Here, the controller can be composed of an arithmetic processing unit including a CPU and a memory (ROM, RAM, etc.).

  FIG. 5 is a schematic hydraulic circuit diagram showing another example (comparative example) of the hydraulic circuit of the construction machine.

  As shown in FIG. 5, the hydraulic circuit of the other example regenerates the return oil via the control valve as compared with the hydraulic circuit 100C (FIG. 3) of the present invention. Energy loss occurs. In addition, the hydraulic circuit of another example is different from the hydraulic circuit 100C of the present invention (for example, FIG. 2) according to the regenerative oil passage (the oil through which the regenerated pressure oil flows) according to the separation distance between the control valve and the hydraulic cylinder. (Path) becomes longer, the pressure loss of the pressure oil (return oil) increases.

  As described above, the embodiment of the construction machine and the hydraulic circuit thereof according to the present invention has been described, but the present invention is not limited to the above-described embodiment. The present invention can be variously modified or changed in light of the appended claims.

100: Construction machine 100C: Hydraulic circuit 10Cb: Cab (operating room, etc.)
10Up: Upper turning body 10Dw: Lower traveling body 11: Boom (attachment)
11c: Boom cylinder (hydraulic cylinder)
12: Arm (attachment)
12c: Arm cylinder (hydraulic cylinder)
13: Bucket (attachment)
13c: Bucket cylinder (hydraulic cylinder)
14m: slewing motor 20: regeneration circuit 21: regeneration oil passage 22: regeneration valve (switching valve etc.)
23: Regeneration release valve 24: Restriction 25: Check valve (check valve)
Cy: Hydraulic cylinder Lvr: Operation lever Pmp: Hydraulic pump Pmp-PL: Pilot pump Tnk: Tank (hydraulic oil tank, etc.)
Vc: Directional control valve (control valve, etc.)
Vsp: Holding valve

Claims (5)

A hydraulic circuit of a construction machine that drives a hydraulic cylinder to operate an attachment,
A regeneration oil passage for regenerating the return oil from the hydraulic cylinder;
A regeneration valve disposed in the regeneration oil path and controlling the flow of the return oil;
A regeneration release valve that is arranged downstream of the regeneration valve and switches a supply destination of the return oil,
The regeneration oil passage is mounted on the attachment.
A hydraulic circuit of a construction machine characterized by the above. The regeneration release valve switches whether the return oil is regenerated or discharged to a tank according to the load of the attachment.
The hydraulic circuit for a construction machine according to claim 1, wherein The regenerative oil passage is arranged side by side with the hydraulic cylinder, and supplies the return oil flowing out from the rod side of the hydraulic cylinder to the bottom side of the hydraulic cylinder.
The hydraulic circuit for a construction machine according to claim 2, wherein: The regeneration release valve switches the supply destination of the return oil using the hydraulic oil pressure supplied from the hydraulic pump to the bottom side of the hydraulic cylinder.
The hydraulic circuit for a construction machine according to claim 3, wherein:   A construction machine comprising the hydraulic circuit according to any one of claims 1 to 4.

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