JPH02248701A - Hydraulic pressure valve with pressure compensation - Google Patents

Abstract

PURPOSE:To avoid two flow forces from working on one spool by forming a meter-in metering portion by a meter-in spool and a meter-out metering portion by a meter-out spool. CONSTITUTION:When pilot pressure liquid is supplied from a port 46, a meter-in spool 16 and a meter-out spool 22 are moved to the left, so that discharge hydraulic pressure of a pump 42 flows in the first chamber 431 of an actuator 43 and the hydraulic pressure in the second chamber 432 returns to a tank 44. At this time, the discharge hydraulic pressure which has flowed in a hollow portion 24 acts on the cylindrical valve 30 of a pressure compensation valve 25 to be moved to the right, the load pressure of a hydraulic actuator enters a back pressure chamber 33 through a pore 35 to move the cylindrical valve 30 to the left, whereby an outlet hole 29 is closed and pressure of another hydraulic valve with pressure compensation is introduced into a pressure receiving chamber 34. When the introduced pressure is higher than the load pressure, the piston 31 of a check valve 26 pushes the cylindrical valve 30 in the cutoff direction to set an external pressure in a pressure compensation valve 25. Thus, the flow control characteristic can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a hydraulic valve with pressure compensation provided in a hydraulic circuit of a power shovel, etc.

[Conventional technology]

Since a power excavator is equipped with multiple hydraulic actuators such as a swing motor, a travel motor, a boom cylinder, an arm cylinder, and a packet cylinder, its hydraulic circuit has multiple hydraulic valves that supply hydraulic pressure to each hydraulic actuator. We are prepared.

In this way, in a hydraulic circuit equipped with multiple hydraulic valves, when two or more hydraulic valves are operated simultaneously, hydraulic pressure is supplied to the hydraulic actuator with a low load pressure, and the hydraulic actuator with a high load pressure is supplied with hydraulic pressure. Hydraulic pressure is no longer supplied.

Therefore, a hydraulic valve with pressure compensation has been proposed as disclosed in Japanese Patent Application Laid-Open No. 188604/1983.

That is, as shown in FIG. 4, a subur 2 is provided in the valve body 1 to communicate and block the inlet ports 3 and 4 with the operating port 5.6, and a bridge passageway that communicates with and blocks the operating port 5.6. A pressure compensating valve is provided at 7, and this pressure compensating valve is configured to be set by the highest operating pressure of the plurality of hydraulic valves, so that a uniform flow rate is provided to the operating ports 5 and 6 of the plurality of hydraulic pressure valves with pressure compensation. By doing so, when a plurality of hydraulic actuators are operated simultaneously, even if the negative pressures differ, a uniform flow rate can be supplied to each hydraulic actuator.

[Problem to be solved by the invention]

Such a pressure compensated hydraulic valve has a first port from the inlet port 3.4;
The flow rate flowing to the second working port 5.6 is controlled by the first
, the flow rate flowing out from the first and second operating ports 5 and 6 to the tank side is controlled by the opening area of the second land parts 2a and 2b, and the flow rate is controlled by the third and fourth land parts 2c and 2b of the spool 2.
It is controlled by 2d.

That is, a meter-in metering section 9a and a meter-out metering section 9b are provided on one spool 2.

For this purpose, a flow force due to the meter-in hydraulic pressure flowing through the meter-in metering section 9a and a flow force due to the meter-out hydraulic pressure flowing through the meter-out metering sections 2c and 2d act on the spool 2, and the spool 2 acts on the spool 2. Since the flow force causes the metering to move in the axial direction, the opening area of each metering section may differ from the set value, resulting in poor flow rate control characteristics.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a hydraulic valve with pressure compensation that can solve the above-mentioned problems.

[Means and effects for solving the problem] A hydraulic valve with pressure compensation is provided with a meter-in spool forming a meter-in metering section and a meter-out spool forming a meter-out metering section. The flow force due to the hydraulic pressure flowing through the in-metering section and the flow force due to the hydraulic pressure flowing through the meter-out metering section act on separate spools, and two flow forces do not act on one spool, so the opening of each metering section The area can be controlled to a set value, improving flow characteristics.

〔Example〕

As shown in FIG. 1, a first shaft hole 11 and a second shaft hole 12 are formed in the valve body lO, and a pump port 13, an outlet port 14, and a pressure introduction port 15 are formed in the ml shaft hole 11. At the same time, a meter spool 16 is inserted into the second shaft hole 12, and the second shaft hole 12 has an artificial port 17, an eleventh second operating port 18, 19, and first and second tank ports 20°2.
1 is formed, and a meter-out spool 22
is an insert.

The meter spool 16 has a cylindrical shape, and the longitudinal direction -
In the example, the bottom wall 16a is integrally formed, and a plug 23 is fitted and fixed to the other side in the longitudinal direction to form a hollow part 24,
A pressure compensation valve 25 and a check valve 26 are provided in the hollow portion 24, and the meter spool 16 is formed with first and second artificial holes 27, 28 and an outlet hole 29.
5 is equipped with a cylindrical valve 30, and the check valve 26 is equipped with a piston 31.
and a piston rod 32, a back pressure chamber 33 is formed between the cylindrical valve 30, the piston 31, and the piston rod 32, and a chamber 34 is formed between the piston 31 and the bottom wall 16a,
The back pressure chamber 33 is in open communication with the outlet hole 29 through a small hole 35, and the back pressure chamber 33 and the chamber 34 are communicated with each other through a liquid path 36, and the chamber 34 is connected to the pressure introduction port 15 through a small hole 37. The meter spool 16 communicates with the pump port 13 and the first and second manhole holes 27 by a pair of left and right springs 38 and 38.
．． 28 is held in a neutral position, and is slid from side to side by pilot hydraulic pressure supplied to the first and second pressure receiving chambers 391 and 392.

The meter spool 22 is held in a neutral position blocking each port by a pair of springs 40, 40, and the first pressure receiving chamber 41. is pushed to the left by the pilot hydraulic pressure supplied to the first position, and moves to the first position where the inlet port 17 and the first operating port 18 are communicated, and the second operating port 19 and the second tank 21 are communicated. It is pushed to the right by the pilot hydraulic pressure supplied to the pressure receiving chamber 412 and moves to the second position where the inlet port 17 and the second operating port 19 are communicated, and the first operating port 18 and the first tank port 20 are communicated. The first pressure receiving chamber 411 and the '1s2 pressure receiving chamber 412 communicate with the first pressure receiving chamber 391 and the second pressure receiving chamber 392 of the meter spool 18, respectively.

A discharge passage of the hydraulic pump 42 communicates with the pump port 13, the first and second operating ports 18.19 communicate with the first and second chambers 431 and 432 of the hydraulic actuator 43, and the first
, the second tank port 20°21 communicates with the tank 44.

Next, the operation will be explained.

When the pilot pressure liquid is supplied from the first port 46, the pilot pressure liquid is supplied to each of the first pressure receiving chambers 411+391, and the meter-in spool 16 and the meter-out spool 2
2 is pushed to the left, and as shown in Fig. 2, the pump port 13 and the first intake port 27 communicate with each other, the inlet port 17 and the first operating port 18 communicate with each other, and the second operating port 19 communicates with the second tank port 19. It communicates with port 21.

As a result, the discharge hydraulic pressure of the hydraulic pump 42 is changed from the pump port 13 → the first manhole 27 → the hollow part 24 → the outlet hole 29 → the inlet port 17 → the first operating port 18 → the first chamber of the hydraulic actuator 43. 431, and the hydraulic pressure in the second chamber 432 flows from the second operating port 19 to the second tank port 21 to the tank 44, so the hydraulic actuator 43 operates in one direction.

At this time, the liquid pressure flowing into the hollow part 24 acts on the cylindrical valve 30 of the pressure compensating valve 25 and pushes it to the right, opens the hollow part 24 to the outlet hole 29, and flows from the outlet hole 29 to the inlet port 17. ,
The pressure of the first actuation port 18 (load pressure of the hydraulic actuator 43) flows into the back pressure chamber 33 through the pore 35 and flows into the cylindrical valve 3.
0 to the left to block the hollow part 24 and the outlet hole 29, and the pressure in the pressure chamber 34 of another pressure compensated hydraulic valve is introduced into the pressure chamber 34 from the pressure introduction port 15. The pressure is compared with the pressure in the back pressure chamber 33, and when the introduced pressure is high, the piston 31 is pushed and the piston rod 32 is used to push the cylindrical valve 30 in the aforementioned shutoff direction, and when the introduced pressure is low, the back pressure chamber 33 is Piston 31 due to internal pressure
is pushed to the right, and the back pressure chamber 33 and the pressure receiving chamber 34 are communicated through the liquid path 36, and the pressure in the back pressure chamber 33 is transferred to the pressure receiving chamber 34, the pressure introduction port 15, and the other pressure receiving pressure valve with pressure compensation. supply to the room.

Because of this, the pressure compensating valve 25 is set to a pressure commensurate with the load pressure, and when a plurality of pressure compensating hydraulic valves are operated simultaneously, the pressure compensating valve 25 is set to a pressure commensurate with the highest load pressure.

At the same time, the highest load pressure is supplied to the capacity control cylinder 45 of the hydraulic pump 42, and the discharge pressure is controlled to be a predetermined pressure, for example, 2.0 kg/c- higher than the detected highest load pressure. .

From the above, when using multiple hydraulic valves with pressure compensation to simultaneously supply hydraulic pressure to multiple hydraulic actuators,
Even if the load pressure of each hydraulic actuator is different, the flow can be distributed and supplied.

In addition, the meter-in flow rate is controlled by the first input 27 of the meter-in valve 16 and the opening area of the pump port 13, and the meter-out flow rate is controlled by the opening area of the second operating port 19 and the second tank port 21 of the meter-out valve 22. is controlled, the meter-in metering section and the meter-out metering section are formed by separate spools, and since two flow forces do not act on one spool, the opening area of each is set to the set value. The flow rate control characteristics are improved.

Moreover, since the meter-in spool 16 is cylindrical and has a pressure compensation valve 25 and a check valve 26 built into it, the valve body 10 has a first shaft hole 11 into which the meter-in spool 16 is inserted, and a meter-out spool 22. The second shaft hole 1 into which the
2, the valve body 10 can be manufactured easily.

FIG. 3 shows an example of use, in which two pressure-compensated hydraulic valves are provided on the discharge side of the hydraulic pump 42 to supply hydraulic pressure to two hydraulic actuators, for example, a boom cylinder 60 and an arm cylinder 61 of a power excavator. First,
Second pressure compensation valve 35. ．． 352 is the metering part, that is, the outlet port 13 and the first and second pump ports 14°15
Since the metering section is provided on the downstream side of the communication and cutoff section 62, the flow rate can be controlled by changing the opening degree of the metering section.

〔Effect of the invention〕

Since the meter-in metering section is formed by the meter-in spool 16 and the meter-out metering section is formed by the meter-out spool 22, the opening area of each metering section can be reduced without two flow forces acting on one spool. can be controlled to the set value, improving flow control characteristics.

[Brief explanation of drawings]

'W41 is a sectional view showing an embodiment of the present invention, FIG. 2 is an explanatory view of the operation, FIG. 3 is an explanatory view of an example of use, and FIG. 4 is a sectional view of a conventional example. 10 is the valve body, 13 is the pump port, 15 is the pressure introduction port, 16 is the meter spool, 17 is the inlet port,
18.19 is the first, 'M2 working port, 20.21 is the first and second tank port, 22 is the meter out spool,
25 is a pressure compensation valve, and 26 is a check valve. Applicant Komatsu Ltd. Representative Patent Attorney Masaaki Yonehara

Claims (1)

[Claims] A pump port 13, an inlet port 17, first and second operating ports 18, 19, and first and second tank ports 20, 21 are formed in the valve body 10, and the pump port 13 and the inlet port 17 are formed in the valve body 10. A meter-in metering section is provided by providing a meter-in metering spool 16 that connects and blocks communication between the inlet port 17 and the first and second operating ports 18, 19, and between the first and second operating ports 18, 19 and the first, A meter-out metering section is formed by providing a meter-out spool 22 that connects and blocks the second tank ports 20 and 21, and the inlet port 17
A pressure compensating valve 25 is provided to set the pressure according to the load pressure of the first and second operating ports 18 and 19, and the external pressure in the pressure introduction port 15 is compared with the load pressure, and if the external pressure is high, This is a hydraulic valve with pressure compensation, characterized in that a check valve 26 is provided for setting the pressure compensation valve 25 by external pressure.