JP2001304202A - Fluid pressure circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase a seep through the increase of a regeneration flow a rate of a working oil and to prevent the increase of the installation space of a regeneration circuit. SOLUTION: The working oil fed from two hydraulic pumps 36 and 37 is controlled into respective directions and flow rates by two arm spools 41 and 42 and a signal arm cylinder 6c is actuated by the working oil. The return oil from a chamber 34 on the rod side of an arm cylinder 6c is regenerated to a chamber 35 on the head side of an arm cylinder 6c through respective regeneration passages 93 and 94 in the arm spools 41 and 42. The regeneration passages 93 and 94 contain regeneration check valves 101 and 102, respectively, actuated for opening in a direction, in which the return oil from the arm cylinder 6a is caused to be confluent with the working oil fed from the hydraulic pumps 36 and 37, and blocking a flow in the reverse direction. A ratio between a regeneration flow rate of the oil regenerated through the regeneration passages 93 and 94 and a discharge flow rate of the oil discharged to an external part is decided by an orifice 115 mounted on the arm spool 41.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fluid pressure circuit having a regeneration function.

[0002]

2. Description of the Related Art FIG. 4 shows a hydraulic excavator. An upper revolving unit 3 is provided on a lower traveling unit 1 via a revolving bearing unit 2 so as to be revolvable, and a front work machine 4 is mounted on the upper revolving unit 3. ing. In the front working machine 4, the base end of the boom 5 is pivotally attached to the upper swing body 3 so as to be rotatable.
A base end of an arm 6 is rotatably connected to a distal end of the arm 6, and a bucket 7 is rotatably connected to a distal end of the arm 6. The boom 5 is turned by a boom hydraulic cylinder 5c, the arm 6 is turned by an arm hydraulic cylinder 6c, and the bucket 7 is turned by a bucket hydraulic cylinder 7c.

A single rod type hydraulic cylinder for an arm (hereinafter, the hydraulic cylinder for an arm is simply referred to as an "arm cylinder") 6c is integrated with a piston 12 from a cylinder body 11 by a regeneration circuit shown in FIG. The extension operation of pushing out the rod 13 can speed up the arm-in operation of pulling the arm 6 toward the body.

FIG. 5A shows a conventional regeneration circuit at the time of arm-in operation, in which a discharge port of a hydraulic pump 14 is provided with an arm cylinder control spool (hereinafter, simply referred to as an arm spool control spool) of a control valve. The arm-in cylinder is provided by the meter-in passage 16 through 15).
The rod side chamber 18 which is formed on the rod side of the piston 12 of the arm cylinder 6c is communicated with the head side chamber 17 which is formed on the head side of the piston 12 of the arm cylinder 6c. Have been.

[0005] In the arm spool 15, an unload valve 21 is provided.
And a regeneration passage 22 branched from the unload valve 21 on the cylinder side and communicating the meter-out passage 19 with the meter-in passage 16. In the regeneration passage 22, a regeneration check valve 23 for preventing backflow is provided. The unload valve 21 closes the meter-out passage 19 by the urging force of the spring 24, and switches to communicate with the meter-in passage 16 by the load pressure introduced from the pilot passage 25.

The arm spool 15 is a three-position switching valve as shown in FIG. 5B, and can freely control the extension, stop, and contraction of the arm cylinder 6c.
(A) shows only the extension operation position related to the arm-in operation.

During the arm-in operation, the hydraulic pump
The hydraulic oil supplied from 14 passes through the arm spool 15,
While supplying to the head side chamber 17 of the arm cylinder 6c,
The return oil flowing out of the rod side chamber 18 is combined with the hydraulic oil supplied from the hydraulic pump 14 through the regeneration check valve 23 of the regeneration passage 22 and is regenerated to the head side chamber 17 so that the discharge flow rate of the hydraulic pump 14 becomes insufficient. To make up for it.

FIG. 6 shows another conventional regeneration circuit at the time of the arm-in operation. The unload valve 21, the regeneration passage 22, and the regeneration check valve 23 are provided outside the arm spool 15. The reproduction spool 26 is provided in the reproduction passage 22, and the reproduction spool 26 is switched so that the reproduction passage 22 is communicated by the pilot control pressure for controlling the arm spool 15 to the arm-in operation position.
Although it is different from the conventional example, since the other structure is the same,
Corresponding parts have the same reference characters allotted, and description thereof will not be repeated.

FIG. 7 shows two hydraulic pumps 14a, 1a.
4b shows a conventional regeneration circuit at the time of arm-in operation for supplying hydraulic oil to one arm cylinder 6c from the hydraulic pump 14b.
a, 14b are respectively connected to meter-in passages 16a, 16a through two arm spools 15a, 15b in the control valve.
6b, the rod side chamber 18 which is communicated with the head side chamber 17 which is defined on the head side from the piston 12 of the arm cylinder 6c, and the rod side chamber 18 which is defined on the rod side from the piston 12 of the arm cylinder 6c has one side formed by the meter-out passage 19. It is configured to be able to communicate with the tank 20 via the internal passage of the arm spool 15a.

In the internal passage of the arm spool 15a,
An orifice 27 for reducing the flow rate of hydraulic oil discharged to the tank 20 is provided, and a regeneration passage 22 branched from the internal passage on the cylinder side from the orifice 27 is provided with one hydraulic pump.
It communicates with the meter-in passage 16a from 14a. In the regeneration passage 22, a regeneration check valve 23 for preventing backflow is provided.

During the arm-in operation, the hydraulic oil supplied from both hydraulic pumps 14a and 14b is supplied to the head side chamber 17 of the arm cylinder 6c via the arm spools 15a and 15b, and the meter is supplied from the rod side chamber 18 to the meter. Out passage
The return oil flowing out through 19 is combined with the hydraulic oil supplied from one of the hydraulic pumps 14a through the regeneration passage 22, and is regenerated to the head-side chamber 17, thereby compensating for the insufficient discharge flow rate of the hydraulic pumps 14a and 14b. Like that.

As described above, in a hydraulic excavator, as a means for obtaining a working speed higher than a limited pump capacity,
A regeneration circuit is provided in the arm hydraulic circuit to speed up the arm-in operation in particular.

[0013]

In the conventional regeneration circuit shown in FIG. 5, a regeneration passage 22 is provided inside an arm spool 15, and further, both an unload valve 21 and a regeneration check valve 23 are built in. Therefore, the space can be saved, but on the other hand, the diameter of the regeneration passage 22 is narrowed, and the regeneration passage 22 is narrowed, so that there is a problem that the flow rate of the recyclable hydraulic oil, that is, the regeneration flow rate is limited.

The conventional reproducing circuit shown in FIG.
Unload valve 21 and regeneration passage 2 outside arm spool 15
2. Since the regeneration check valve 23 and the dedicated regeneration spool 26 are provided, a sufficient regeneration flow rate can be ensured by the regeneration passage 22 having a sufficient cross-sectional area. However, there is a disadvantage in terms of installation space.

Further, the conventional regeneration circuit shown in FIG. 7 supplies hydraulic oil to one arm cylinder 6c from two hydraulic pumps 14a and 14b, so that the conventional regeneration circuit shown in FIG. 5 or FIG. Although a large amount of hydraulic oil can be supplied, since the return oil is regenerated by one regeneration passage 22, the diameter of the regeneration passage is not sufficient, and the arm-in required for a hydraulic shovel of a model equipped with this regeneration circuit is required. The regeneration flow is not yet sufficient to obtain operating speed.

In the regeneration circuit shown in FIG. 7, the regeneration flow rate can be increased by reducing the orifice 27. However, if the orifice 27 is reduced too much, there is a problem that the resistance during excavation increases.

As described above, conventionally, the flow rate of the regeneration is limited by the diameter of the regeneration passage, and there is a problem that either the operation speed is saturated or the installation space is disadvantageous.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object to increase the regeneration flow rate of a working fluid to increase the speed and prevent an increase in the installation space of a regeneration circuit. is there.

[0019]

According to the first aspect of the present invention, there are provided a plurality of valve bodies for respectively controlling at least directions of a working fluid supplied from a plurality of pumps, and a working fluid controlled by the plurality of valve bodies. And a plurality of regeneration passages for regenerating fluid returned from the fluid pressure actuator to the working fluid supply side of the fluid pressure actuator through a plurality of valve bodies. Since the regeneration flow rate of the working fluid can be increased by a plurality of regeneration passages to increase the speed, and each regeneration passage regenerates the working fluid through a plurality of valve bodies,
Space saving can be achieved as compared with the case where it is provided outside.

According to a second aspect of the present invention, the regeneration passage according to the first aspect opens in a direction in which the fluid returned from the fluid pressure actuator joins with the working fluid supplied from the pump, and flows in the reverse direction. A fluid pressure circuit including an orifice that includes a regeneration check valve for preventing the flow rate of the fluid regenerated in the regeneration passage and the discharge flow rate of the fluid discharged to the outside.
The flow rate of the working fluid regenerated through the regeneration check valve and the flow rate discharged to the outside are appropriately distributed.

According to a third aspect of the present invention, the orifice and the regeneration check valve according to the second aspect are a fluid pressure circuit provided in a valve body, and are provided when the orifice and the regeneration check valve are installed outside. Prevent space increase.

According to a fourth aspect of the present invention, a plurality of valve bodies for controlling at least the directions of the working fluids supplied from the plurality of pumps, respectively, and one valve operated by the working fluid controlled by the plurality of valve bodies. A fluid pressure actuator;
A regeneration passage for regenerating the fluid returned from the fluid pressure actuator through one valve body to the working fluid supply side of the fluid pressure actuator, a regeneration flow rate of the fluid regenerated in the regeneration passage, and a discharge flow rate of the fluid discharged to the outside And an unload valve that discharges the fluid returned from the fluid pressure actuator to the outside through another valve body in a low load state, and sufficiently restricts the orifice. By increasing the regeneration flow rate of the working fluid in the regeneration passage in one valve body to increase the speed,
The inconvenience caused by excessively narrowing the orifice is eliminated by the unload valve.

According to a fifth aspect of the present invention, the regeneration passage of the fourth aspect opens in a direction in which the fluid returned from the fluid pressure actuator joins the working fluid supplied from the pump, and flows in the reverse direction. The fluid pressure circuit includes a regeneration check valve for preventing the flow rate of the working fluid, and maintains the flow rate of the working fluid regenerated through the regeneration check valve appropriately for the flow rate discharged to the outside through the orifice.

According to a sixth aspect of the present invention, there is provided a fluid pressure circuit in which the orifice and the regeneration check valve according to the fifth aspect are provided in one valve body, and the unload valve is provided in another valve body. By separately installing the orifice and regeneration check valve and the unload valve in the two valve bodies,
Space saving of the reproduction circuit is achieved.

According to a seventh aspect of the present invention, the pump according to any one of the first to sixth aspects is a hydraulic pump mounted on a hydraulic shovel, and the fluid pressure actuator is provided in a front working machine of the hydraulic shovel. A single rod type arm hydraulic cylinder for operating the arm, comprising a rod side chamber defined on the rod side of the piston, and a head side chamber defined on the opposite side, and the valve element is an arm hydraulic cylinder. A fluid that regenerates return oil flowing out of the rod side chamber of the arm hydraulic cylinder to the head side chamber of the arm hydraulic cylinder through the inside of the arm spool; Pressure circuit, which increases the regeneration flow rate of hydraulic oil regenerated from the rod side chamber of the arm hydraulic cylinder to the head side chamber via the regeneration passage. Te, along with attained to speed up Amuin operation of the front work device of a hydraulic excavator, since to reproduce the hydraulic oil through the regeneration passage in the arm spool, thereby saving space in the reproduction circuit than provided outside.

[0026]

Next, an embodiment of the present invention will be described with reference to FIGS.

In FIG. 1, reference numeral 6c denotes an arm hydraulic cylinder as a fluid pressure actuator for operating the arm 6 in the front working machine 4 (FIG. 4) of the hydraulic shovel (hereinafter, this arm hydraulic cylinder is simply called "arm cylinder"). It is).

The arm cylinder 6c is a single rod type hydraulic cylinder, in which a piston 32 is slidably fitted in a cylinder body 31, and a rod side chamber 34 is defined on the rod 33 side from the piston 32. A head side chamber 35 is formed on the opposite side.

A hydraulic circuit as a fluid pressure circuit for controlling the arm cylinder 6c includes two hydraulic pumps 36 and 37 as a plurality of pumps, and a hydraulic fluid as a working fluid supplied from the hydraulic pumps 36 and 37. And a control valve 38 for controlling the direction and flow rate of each of them to supply them to the arm cylinder 6c and the like.

The hydraulic pumps 36 and 37 are variable displacement pumps driven together by an engine mounted on a hydraulic shovel, and suck hydraulic oil from a tank 39.

The control valve 38 is provided inside the valve body 40,
A plurality of spools as valve bodies for controlling various hydraulic actuators mounted on a hydraulic shovel are arranged in parallel, and two arms as a plurality of valve bodies for controlling one arm cylinder 6c are provided therein. Cylinder control spools (hereinafter, arm cylinder control spools are simply referred to as “arm spools”) 41 and 42 are included.

The arm spools 41 and 42 are provided with a valve body.
A force generated by a pilot pressure from an operating lever acting on a pilot operating portion 45, 46 provided at one end of each spool, which is slidably fitted into a spool fitting hole 43, 44 formed in each of the spools. Then, the spool is displaced to a position where the repulsive force of the return springs 47 and 48 provided at one end of each spool is balanced and stopped.

In the valve body 40, load check valves 53 and 54 for maintaining the load pressure, which receive the supply of the working fluid from the respective discharge passages 51 and 52 from the hydraulic pumps 36 and 37, are provided. Hydraulic oil supply passages 55 and 56, which are divided into two via check valves 53 and 54, are formed.
A pair of hydraulic oil supply grooves 57 and 58 are provided around the periphery of the cylinder 42, respectively.

The hydraulic oil supply groove 57 on the right side of the one arm spool 41 is elongated in the axial direction by additionally forming a concave groove 57a.

In one load check valve 53, a check valve portion 62 is slidably fitted to the outer peripheral surface of a cylindrical portion 61 fixed to the valve body 40, and the check valve portion 62 is compressed by a compression coil spring 63. It is pressed against the valve seat 64.

When the check valve portion 62 of the load check valve 53 is lifted up by the hydraulic oil supply pressure from one of the hydraulic pumps 36 against the compression coil spring 63,
The valve seat 64 communicated with one hydraulic pump 36 opens,
Each of the arm spools 41 is communicated with the hydraulic oil supply passage 55 divided into two parts and one of the arm spools 41 from the upper opening of the cylindrical portion 61.
Is communicated with a hydraulic oil groove 65 provided around a central portion of the hydraulic fluid.

The other load check valve 54 has a check valve 67 slidably fitted in a hollow screw member 66 screwed to the valve body 40, and the check valve 67 is connected to a compression coil spring 68. To the valve seat 69.

The discharge passage 52 from the other hydraulic pump 37 is always in communication with a hydraulic oil groove 70 provided around the central portion of the other arm spool 42. When the valve portion 67 is lifted up against the compression coil spring 68 by the hydraulic oil supply pressure from the other hydraulic pump 37, the valve seat portion 69 communicated with the other hydraulic pump 37 is opened and divided into two. The hydraulic oil supply passages 56 communicate with each other.

Hydraulic oil grooves 65 and 70 provided around the center of each of the arm spools 41 and 42 respectively
When 41 and 42 are in the neutral position, they communicate with hydraulic oil discharge grooves 73 and 74 provided at adjacent positions via circumferential grooves 71 and 72 provided on the peripheral surfaces of these arm spools 41 and 42, respectively. Have been. These hydraulic oil discharge grooves 73 and 74 are connected to the tank 39 by a passage 75.

The upper and lower working oil supply grooves 57,
At the position adjacent to 58, the upper and lower hydraulic oil supply / discharge grooves 77, 78 divided around the arm spools 41, 42 are divided into right and left parts.
Are provided respectively, these upper and lower hydraulic oil supply and discharge grooves 77,
78 is communicated with left and right passages 79 and 80, respectively, and left and right passages 81 and 82 in the valve body 40 and external passages 83 and 84.
The rod side chamber 34 and the head side chamber 35 of the arm cylinder 6c
And each is communicated with.

The upper and lower hydraulic oil supply grooves 57 and 58 divided into two parts on the left and right, and the upper and lower hydraulic oil supply and discharge grooves 7 divided into two parts on the left and right.
7 and 78 are adjacent to each other.
By the axial displacement of the arm spools 41, 42, the communication can be made respectively by the circumferential grooves 85, 86 provided on the left and right peripheral surfaces of the arm spools 41, 42.

Further, at positions adjacent to the upper and lower hydraulic oil supply / discharge grooves 77 and 78 divided into two sides, the upper and lower hydraulic oil divided around the arm spools 41 and 42 are divided into two parts. Discharge grooves 87 and 88 are provided, respectively, and these hydraulic oil discharge grooves 87 and 88 are communicated with left and right passages 89 and 90, respectively, and further communicated with the tank 39 by a passage 75.

The upper and lower hydraulic oil supply / discharge grooves 77 and 78 divided into two parts on the left and right, and the upper and lower hydraulic oil discharge grooves 8 divided into two parts on the left and right.
The adjacent ones at 7,88 are the arm spools 41,42
Can be communicated with the arm grooves 41, 42 by the circumferential grooves 85, 86, respectively.

On the right side of the valve body 40, a passage 82 communicating with one of the working oil supply / discharge grooves 77, 78 and a passage 91 communicating with the one of the working fluid discharge grooves 87, 88 are provided. A relief valve 92 for setting the upper limit of the circuit pressure is provided to prevent the load pressure of the arm cylinder 6c from excessively increasing.

Inside the two arm spools 41 and 42,
Regeneration passages 93 and 94 are provided to regenerate the return oil flowing out from the rod side 34 of the arm cylinder 6c to the head side chamber 35 of the arm cylinder 6c via the inside of each arm spool 41 and 42, respectively.

Regeneration passages 93 and 94 provided in each of the arm spools 41 and 42 have radial holes 95 and 96 respectively communicating with upper and lower hydraulic oil supply / discharge grooves 77 and 78 located on the left side. Axial holes 97, communicating with the radial holes 95, 96, respectively.
98 and radial holes 99, 98 which can communicate with these upper and lower hydraulic oil supply / discharge grooves 77, 78 located on the right side.
100 and each.

Further, these regeneration passages 93 and 94 are opened in the direction in which the return oil flowing out of the rod side chamber 34 of the arm cylinder 6c and the hydraulic oil supplied from the respective hydraulic pumps 36 and 37 are opened, and in the opposite direction. It includes regeneration check valves 101 and 102 for blocking flow, respectively.

The regenerative check valves 101 and 102 are provided with axial holes 103 and 104 slightly larger in diameter than the axial holes 97 and 98 in the right sides of the arm spools 41 and 42 via valve seats 105 and 106. Check valve portions 107, 1 which can be freely moved toward and away from the respective valve seat portions 105, 106 respectively.
08, compression coil springs 109 and 110 for pressing the check valves 107 and 108 against the valve seats 105 and 106, respectively, and spring receiving members 111 and 112 for receiving the compression coil springs 109 and 110, respectively. Screws 113 and 114 which are fitted respectively and lock these spring receiving members 111 and 112 are screwed respectively.

A plurality of groove-shaped orifices 115 having different lengths are provided in the axial direction on the peripheral surface on the left side of the peripheral groove 85 provided on the left side of one arm spool 41.

These orifices 115 provide a regeneration flow rate at which the return oil flowing out of the rod side chamber 34 of the arm cylinder 6c is regenerated to the head side chamber 35 in the regeneration passage 93 by the displacement of the arm spool 41 to the left, and a hydraulic oil supply. The ratio between the discharge flow rate of the hydraulic oil discharged from the discharge groove 77 through the orifice 115 and the hydraulic oil discharge groove 87 to the external tank 39 is determined, and the flow rate of the hydraulic oil regenerated through the regeneration check valve 101 is determined. Appropriately distribute the flow discharged to the outside.

As described above, since the regeneration check valves 101 and 102 and the orifices 115 are provided on the arm spools 41 and 42, they are installed along with an increase in size when these are installed outside the arm spools 41 and 42. An increase in space can be prevented.

Next, the operation of the embodiment shown in FIG. 1 will be described with reference to a simplified drawing shown in FIG.

First, referring to FIG. 1, when a pilot operation is performed so that each of the arm spools 41, 42 is displaced to the left, the hydraulic oil discharged from the hydraulic pumps 36, 37 causes the load check valves 53, 54 to be discharged. , Right hydraulic oil supply passages 55 and 56, right hydraulic oil supply grooves 57 and 58, right peripheral grooves 85 and 86 of arm spools 41 and 42, right hydraulic oil supply and discharge grooves 77 and 78, passages 80 and 82. And through the passage 84 to the head side chamber 35 of the arm cylinder 6c.

At this time, the rod side chamber of the arm cylinder 6c
The return oil extruded from 34 is supplied to passage 83, passages 81 and 79, left working fluid supply / discharge grooves 77 and 78, left peripheral grooves 85 and 86 of arm spools 41 and 42, and left working fluid discharge groove 87. , 88 and the passages 89, 75 to the tank 39, the arm cylinder 6c operates in the direction in which the rod 33 extends, so that a so-called arm-in operation in which the arm 6 of the hydraulic shovel approaches the body.

FIG. 2 shows the switching state during the arm-in operation due to the leftward displacement of each of the arm spools 41 and 42. A part of the return oil flowing out of the rod side chamber 34 of the arm cylinder 6c is 42 flows into the regeneration passages 93 and 94, respectively, and the check valves of the regeneration check valves 101 and 102 respectively.
107 and 108 are pushed open respectively against the respective compression coil springs 109 and 110, and radial holes in one arm spool 41 are formed.
The return oil that has flowed out of the 99 flows into the groove 57a and the hydraulic oil supply groove 5
7, the peripheral groove 85, the hydraulic oil supply / discharge groove 77, and the passage 82,
The return oil which is regenerated from the head side chamber 35 of the arm cylinder 6c to the head side chamber 35 and flows out from the radial hole 100 in the other arm spool 42 is joined to the passage 82 via the hydraulic oil supply / drain groove 78 and the passage 80. , From the passage 84 to the head side chamber 35 of the arm cylinder 6c.

At this time, the rod side chamber of the arm cylinder 6c
The remaining oil that is not regenerated even when returned from the tank 34, the orifice 115 of one arm spool 41, the hydraulic oil discharge groove 87, the passage 8
The gas is discharged to the external tank 39 through the passage 9 and the passage 75. The ratio between the discharge flow rate and the regeneration flow rate is determined by the orifice
115 and varies depending on the amount of spool displacement.

On the other hand, when each of the arm spools 41 and 42 is operated by a pilot so as to be displaced rightward, the hydraulic pumps 36 and 42 are moved.
Hydraulic oil discharged from 37 is the load check valves 53, 54,
The hydraulic oil supply passages 55 and 56 on the left and the hydraulic oil supply grooves 57 on the left
It is supplied to the rod-side chamber 34 of the arm cylinder 6c through the peripheral grooves 85 and 86 on the left side of the arm spools 41 and 42, the hydraulic oil supply / discharge grooves 77 and 78 on the left side, the passages 79 and 81, and the passage 83.

At this time, the head side chamber of the arm cylinder 6c
The return oil extruded from the pipe 35 is supplied to the passage 84, the passages 82 and 80, the right working fluid supply and discharge grooves 77 and 78, the right peripheral grooves 85 and 86 of the arm spools 41 and 42, and the right working fluid discharge groove 87. , 88, passage 90
The arm cylinder 6c is operated in a direction in which the rod 33 contracts and the arm 6 of the excavator is operated in a direction in which the arm 6 of the hydraulic shovel is separated from the machine body.

As described above, at the time of the arm-in operation, the regenerating passages 93 and 94 provided in the two arm spools 41 and 42 respectively make it possible to compare with the conventional example shown in FIG.
Since a double regeneration passage cross-sectional area can be secured, the regeneration flow rate of the hydraulic oil regenerated from the rod side chamber 34 of the arm cylinder 6c to the head side chamber 35 is also doubled, and the arm-in operation in the front work machine 4 of the hydraulic shovel Can be further speeded up.

Further, since the regeneration passages 93 and 94 and the regeneration check valves 101 and 102 are provided inside the arm spools 41 and 42, compared with the case where these are provided outside the arm spools 41 and 42, No external space is required,
Space saving of the reproduction circuit can be achieved.

In short, when the working fluid is regenerated in a circuit that joins the working fluids discharged from a plurality of pumps, the regeneration flow rate is increased by adding a regeneration function to each spool to increase the actuator speed. In addition to this, it is possible to prevent the device from becoming large, which is generally caused by the addition of the reproduction function, and to effectively use existing members.

Next, FIG. 3 shows another embodiment. In the embodiment shown in FIG. 3, the same parts as those in the embodiment shown in FIG. 2 are denoted by the same reference numerals, and the description thereof will be omitted.

Two hydraulic pumps 3 as a plurality of pumps
Two arm spools 41 and 42 as a plurality of valve bodies for controlling the direction and flow rate of the working oil as the working fluid supplied from the working fluids 6 and 37, respectively;
The arm cylinder 6c as one fluid pressure actuator operated by the hydraulic oil as the working fluid controlled by the first and the 42, and the return oil flowing out from the rod side chamber 34 of the arm cylinder 6c are passed through one arm spool 41. A regeneration passage 93 for regeneration to the head side chamber 35 of the arm cylinder 6c, and an orifice 115 for determining a ratio between a regeneration flow rate of the hydraulic oil regenerated in the regeneration passage 93 and a discharge flow rate of the hydraulic oil discharged to the external tank 39. The return oil from the arm cylinder 6c is supplied to the internal passage 116 in the other arm spool 42 in a low load state.
And an unloading valve 117 for discharging to the external tank 39 through the hopper.

The internal passage 116 is a hole in the arm spool 42 which can communicate from the hydraulic oil supply / discharge groove 78 communicating with the passage 79 to the hydraulic oil discharge groove 88, and the unload valve 117 is connected to the internal passage 116. , The internal passage 116 is closed by the urging force of the spring 118, and the spring 118 is pressed by a force generated by the load pressure generated in the head side chamber 35 of the arm cylinder 6 c guided through the pilot passage 119 from the passage 80.
And the internal passage 116 communicates with the tank 39.

The reason why the unload valve 117 is provided is that the orifice 115 is sufficiently throttled in order to increase the regeneration flow rate in the arm spool 41. In this case, however, the resistance during excavation increases with the orifice 115 alone. In addition, an unload valve 117 is also provided to detect a load during excavation and reduce the resistance.

The regeneration passage 93 provided in one arm spool 41 includes a regeneration check valve 101. The regeneration check valve 101 transfers the return oil flowing out of the rod side chamber 34 of the arm cylinder 6c from the hydraulic pump 36. It opens in the direction of merging with the hydraulic oil supply passage and prevents the reverse flow, and also reduces the flow rate of the hydraulic oil regenerated through the regeneration check valve 101 to the flow rate discharged to the external tank 39 through the orifice 115. It is similar to the embodiment shown in FIGS. 1 and 2 in that it is appropriately maintained.

In the circuit shown in FIG. 3, the orifice 115 is sufficiently squeezed to increase the regeneration flow rate of the hydraulic oil in the regeneration passage 93 in one of the arm spools 41 to increase the speed. This orifice 115
The inconvenience caused by over-squeezing is eliminated by the unload valve 117 in the other arm spool 42.

The orifice 115 and the regeneration check valve 101 and the unload valve 117 are connected to two arm spools 4.
By separately installing the orifice 115 and the regeneration check valve 101 in one arm spool 41, the unload valve 117 can be built in the other arm spool 42 compactly. And the space of the reproducing circuit can be saved.

As described above, when the hydraulic circuit shown in FIGS. 1 and 2 or the hydraulic circuit shown in FIG. 3 is applied to the arm cylinder 6c of the hydraulic shovel shown in FIG.
Since the speed of the arm-in operation in the front work machine 4 can be increased, the regeneration passages 93 and 94 including the regeneration check valves 101 and 102 are provided in the arm spools 41 and 42, and the unload valve 117 is provided in the arm spool 42. Since these components are provided outside the spool, the space required for the reproduction circuit can be reduced as compared with the case where these components are provided outside the spool.

[0070]

According to the first aspect of the present invention, the regeneration flow rate of the working fluid can be increased by the plurality of regeneration passages to increase the speed of the fluid pressure actuator, and each regeneration passage in the plurality of valve bodies can be achieved. Since the working fluid is regenerated through the above, space saving can be achieved as compared with the case where the regenerating passage is provided outside.

According to the second aspect of the present invention, the flow rate of the working fluid regenerated through the regeneration check valve and the flow rate discharged to the outside can be appropriately distributed by the orifice.

According to the third aspect of the present invention, it is possible to prevent an increase in installation space when the orifice and the regeneration check valve are installed outside.

According to the fourth aspect of the present invention, the orifice is sufficiently throttled to increase the regeneration flow rate of the working fluid passing through the regeneration passage in the valve body, thereby increasing the speed. Can be eliminated by the unload valve.

According to the fifth aspect of the present invention, the flow rate of the working fluid regenerated through the regeneration check valve can be appropriately maintained with respect to the flow rate discharged to the outside through the orifice.

According to the sixth aspect of the present invention, the orifice and regeneration check valve and the unload valve are separately installed in the two valve bodies, so that the space for the regeneration circuit can be saved.

According to the seventh aspect of the present invention, the regenerative flow rate of the hydraulic oil regenerated from the rod side chamber of the arm hydraulic cylinder to the head side chamber via the regenerating passage is increased, so that the arm-in operation in the front working machine of the excavator. In addition, since the operating oil is regenerated through the regeneration passage in the arm spool, the space for the regeneration circuit can be reduced as compared with the case where the regeneration passage is provided outside.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a fluid pressure circuit according to the present invention.

FIG. 2 is a circuit diagram of the above embodiment in an arm-in operation state.

FIG. 3 is a circuit diagram showing another embodiment of the fluid pressure circuit according to the present invention in an arm-in operation state.

FIG. 4 is an explanatory diagram illustrating an arm-in operation of the excavator.

FIG. 5A is a circuit diagram showing an example of a conventional circuit in an arm-in operation state, and FIG. 5B is a diagram showing a function of the arm spool.

FIG. 6 is a circuit diagram showing an example of another conventional circuit in an arm-in operation state.

FIG. 7 is a circuit diagram showing an example of another conventional circuit in an arm-in operation state.

[Explanation of symbols]

 4 Front work machine 6 Arm 6c Arm cylinder as a fluid pressure actuator 32 Piston 33 Rod 34 Rod side chamber 35 Head side chamber 36, 37 Hydraulic pump 41, 42 Pump hydraulic arm 41, 42 Arm spool 93, 94 Regeneration passage 101, 102 Regeneration Check valve 115 Orifice 117 Unload valve

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Keigo Yasuda, Inventor 8-7-24 Tsuji, Urawa-shi, Saitama Prefecture Kayaba Industry Co., Ltd. Urawa Plant F-term (reference) 2D003 AA01 AB03 CA04 3H051 AA10 BB10 CC11 FF07 3H053 AA25 BC01 DA11 3H059 AA06 BB22 CD05 EE13 FF03 3H089 AA21 AA33 AA72 BB04 BB15 BB27 DA02 DA06 DB07 DB13 DB33 DB65 DB78 DB79 GG02 JJ02

Claims (7)

[Claims] 1. A plurality of valve bodies for at least controlling the directions of working fluids supplied from a plurality of pumps, one hydraulic actuator operated by the working fluid controlled by the plurality of valve bodies, and a hydraulic actuator A plurality of regeneration passages for regenerating the fluid returned from the valve through a plurality of valve bodies to the working fluid supply side of the fluid pressure actuator. 2. The regeneration passage includes a regeneration check valve that opens in a direction in which the fluid returned from the fluid pressure actuator joins with the working fluid supplied from the pump and prevents a reverse flow, and performs regeneration in the regeneration passage. 2. The fluid pressure circuit according to claim 1, further comprising an orifice for determining a ratio between a regeneration flow rate of the fluid to be discharged and a discharge flow rate of the fluid discharged to the outside. 3. The fluid pressure circuit according to claim 2, wherein the orifice and the regeneration check valve are provided on the valve body. 4. A plurality of valve bodies each controlling at least the direction of the working fluid supplied from the plurality of pumps, one hydraulic actuator operated by the working fluid controlled by the plurality of valve bodies, and a hydraulic actuator A regeneration path for regenerating the fluid returned from the valve through one valve body to the working fluid supply side of the fluid pressure actuator, and a ratio of the regeneration flow rate of the fluid regenerated in the regeneration path to the discharge flow rate of the fluid discharged to the outside And an unload valve for discharging the fluid returned from the fluid pressure actuator to the outside through another valve body under a low load condition. 5. The regeneration passage includes a regeneration check valve that opens in a direction in which the fluid returned from the fluid pressure actuator merges with the working fluid supplied from the pump, and prevents a reverse flow. The fluid pressure circuit according to claim 4. 6. The fluid pressure circuit according to claim 5, wherein the orifice and the regeneration check valve are provided in one valve body, and the unload valve is provided in another valve body. 7. The hydraulic pump is a hydraulic pump mounted on a hydraulic shovel, and the hydraulic actuator is a single rod arm hydraulic cylinder for operating an arm in a front working machine of the hydraulic shovel, the hydraulic cylinder being a rod side of the piston. And a head side chamber partitioned on the opposite side, the valve body is two arm spools for controlling an arm hydraulic cylinder, and the regeneration passage is a rod of the arm hydraulic cylinder. The fluid pressure circuit according to any one of claims 1 to 6, wherein the passage is a passage for regenerating return oil flowing out of the side chamber to the head side chamber of the arm hydraulic cylinder through the inside of the arm spool.