JPH03144103A - Pressure compensation valve device - Google Patents

Abstract

PURPOSE:To prevent the pressure in pilot chambers from increasing and perform controlling surely by forming circular grooves around spools, and forming communication grooves for communicating the circular grooves with secondary side ports. CONSTITUTION:Circular grooves 23, 24 are formed around spools 11, 12 between primary side ports 1, 2 and first pilot chambers 15, 16. Communication grooves for communicating the circular grooves 23, 24 with secondary side ports 3, 4 are formed. Pressure oil flowing into the circular grooves 23, 24, flows out to the secondary ports 3, 4 through the communication grooves 25, 26, so that the oil does not flow into the first pilot chambers 15, 16. It is therefore possible to prevent the pressure in the pilot chambers from increasing excessively and prevent inaccurate controlling.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention maintains the differential pressure before and after the variable throttle mechanism constant,
The present invention relates to a pressure compensation valve device that controls a flow rate to a set value regardless of pressure changes.

(Prior art) Fig. 4 shows a system in which one variable discharge pump P drives two actuators A, A2, and controls the discharge pressure of the variable discharge pump P in accordance with the actuator with a high fi load pressure. This figure shows a drive device with a A pair of pressure compensating valves V, , V used in this drive device
2 corresponds to a conventional example of a pressure compensation valve which is a main element of the pressure compensation valve device of the present invention. Therefore, first, while explaining the drive device as a whole, the pressure compensation valve device will also be specifically explained.

1.2 Pressure compensation #PV+, V2 is -・Next side port 1
．． 2 and a secondary port 3.4, and the secondary port 1.2 is connected to a variable discharge pump P via a parallel passage 5.6. In addition, the above-mentioned secondary side port 3.
4 is connected to the 1.2 actuators A1, A2 via a load check valve 7.8 and a variable throttle 9.10.

The 1.2 pressure compensation valves V, , V2 thus constructed have the following:
Does this spool 1 contain spools 11 and 12?
1.12 forms an annular recess 13.14 in the central part;
Depending on the position of this recess 13.14, the primary port 1.2
The flow path area between the secondary port 3.4 and the secondary port 3.4 is controlled.

Furthermore, one end of this spool 11.12 faces the first pilot chamber 15.16, and the other end faces the second pilot chamber 17.
．． I'm planning on turning 18.

The whistle 1 pilot chamber 15.16 is connected between the load check valve 7.8 and the variable throttle 9.10 via a damper orifice 33.34. 2nd pilot room 17.
18 has a spring 19.20 inside, a variable aperture 9.10 and a 1.2 actuator A, , A2
is connected between.

Also, variable aperture 9.10 and 1.2 actuator AI
, A2, a high pressure is selected by the shuttle valve 21, and the pressure is guided to the regulator 22 of the variable discharge pump P.

Now, for example, than the load pressure of the second actuator A2,
If the first actuator A1 is used with a higher load pressure, the load pressure on the first actuator side is selected by the shuttle valve 21 and guided to the regulator 22. Therefore, the variable discharge pump P discharges a flow rate commensurate with the pressure required by the first actuator A1. For this purpose, the pressure compensating valve v1 maintains the normal state shown in the figure by the action of the spring 19, and allows the downstream port 1 and the secondary port 3 to communicate with each other in a fully open state. This allows the first
Actuator A is equipped with a controlled variable discharge pump P.
The flow rate will be supplied from

Discharge oil from the variable discharge pump P flows through the parallel passage 6 into the primary port 2 of the second pressure compensation valve V2 that controls the second actuator A2 with the lower load pressure. However, since the supplied meteor at this time is the flow rate required by the first actuator A1 as described above, the second actuator
The pressure compensation valve v2 controls the flow rate supplied to the second actuator A2 to the flow rate required by the second actuator A2.

That is, the pressure oil flowing into the primary port 2 of the second pressure compensation valve V2 is supplied to the second actuator A2 via the annular recess 14 → secondary port 4 → load check valve 8 → variable throttle 10. At this time, the pressure on the upstream side of the variable throttle 10 is guided to the first pilot chamber 16, and the pressure on the downstream side thereof is guided to the second pilot chamber 18.

Therefore, the second pressure compensation valve v2 compensates for the pressure in the first pilot chamber 16, the second pilot chamber 18 and the spring 2.
The spring force of 0 stops at a balanced position, and the flow path area between the downstream port 2 and the secondary port 4 is controlled. That is, this second pressure compensation valve V2 is configured such that the differential pressure before and after the variable throttle 10 is equal to the spring force of the spring 20.
The moving position of the spool 12 is controlled. In this way, the second pressure compensation valve v2 operates so that the differential pressure across the variable throttle 10 is constant, so the flow rate supplied to the second actuator A2 is always constant regardless of its load pressure.

(Problem to be solved by the invention) In the conventional device as described above, the primary port 1.2
Side pressure oil may flow into the first pilot chamber 15.16 through the gap around the spool 11.12.

In this way, when the pressure oil from the downstream port 1.2 flows into the first pilot chamber 15.16, this pilot chamber 15.1
The pressure inside 6 will increase. In particular, in the case of the conventional example shown in the figure, the damper orifice 33.34 is provided on the first pilot chamber 15.16 side, so when pressure oil flows into this first pilot chamber, it is difficult for the pressure oil to escape. As a result, pressure is often trapped in the first pilot chamber.

Therefore, this conventional pressure compensation valve device has a problem in that it is not possible to accurately control the pressure compensation valves vl and V2.

In addition, the primary side port 1.2 of this pressure compensation valve Vl, V2
When the annular recess 13.14 communicates with the recess 13.
．． The fluid force of the pressure oil flowing into the spool 11.
12 sometimes rotated. When the spool rotates in this way, it may wear unevenly. In particular, spool 1
Abrasion powder is generated by friction P5 between spring 1.12 and spring 19.20, and the spool may be damaged by the influence of this abrasion powder.

For this reason, this conventional pressure compensating valve device has a problem in that if the spool is scratched or worn unevenly, accurate control cannot be achieved.

In order to solve the above problem, the object of the first invention is-
It is an object of the present invention to provide a pressure compensating valve device that prevents pressure oil from a next port from flowing into a first pilot chamber.

A second object of the invention is to provide a device in which the spool does not rotate even when fluid force is applied.

(Means for Solving the Problems) In order to achieve the above object, the present invention forms a primary side port communicating with a pressure source and a secondary side port communicating with an actuator, and a flow path between these two ports. A spool for controlling the area is provided, one end of the spool faces the first pilot chamber, and the other end faces the second pilot chamber, and a variable throttle mechanism is provided between the secondary port and the actuator. Guide the pressure between the secondary port and the variable throttle mechanism to the first pilot chamber, guide the pressure between the variable throttle mechanism and the actuator to the second pilot chamber,
The differential pressure before and after the variable throttle mechanism.

This method is based on a pressure compensating valve device that moves the spool to maintain a set value and controls the flow path area between the next port and the second port.

Note that the variable throttle mechanism mentioned above naturally includes a directional control valve and the like in addition to the variable throttle valve.

Based on the above-mentioned device, the first invention provides -
The present invention is characterized in that an annular groove is formed on the circumferential surface of the spool between the next port and the first pilot chamber, and a communication groove is formed to communicate this annular groove with the secondary port.

Further, in the second invention, a protrusion is provided on either one end of the spool or the pilot chamber, and the protrusion is fitted on the other end of the spool or the pilot chamber to prevent rotation thereof. It is characterized by the provision of a recess.

(Operation of the present invention) In the first invention, pressure oil leaking from the downstream port through the spool peripheral surface flows into the annular groove and flows out to the secondary port via the communication groove.

Furthermore, in the second aspect of the invention, since the protrusion provided on the spool and the recess are fitted together, rotation of the spool can be completely prevented even if fluid force is applied.

(Effects of the present invention) According to the device of the first invention, the pressure oil at the downstream port does not flow into the ballot chamber, so the pressure in the pilot chamber becomes too high, resulting in inaccurate control. can solve the problem.

Further, according to the device of the second invention, since the spool does not rotate even when fluid force is applied, the spool does not wear unevenly, and accurate control is always possible.

(Embodiment of the present invention) The first embodiment shown in FIG.
．． 12, an annular groove 23.24 is formed therein, and a communication groove 25.26 is formed to communicate this annular groove 23.24 with the secondary side port 3.4.

The configuration other than the above is the same as that of the conventional device shown in FIG. 4, so the same reference numerals are given to the common components, and detailed explanation of each component will be omitted.

The main points of the first embodiment will be explained below.

Even if the pressure oil on the primary port 1.2 side passes around the spool 11.12 and leaks to the first pilot chamber 15.16 side, it will leak into the annular groove before reaching the first pilot chamber 15.16. It flows into 23.24 and ends with ν. Moreover, the pressure oil that has flowed into the annular grooves 23 and 24 is
5.26 to the secondary port 3.4,
Pressure oil no longer flows into the first pilot chamber 15,16.

The variable throttles 9 and 10 in this embodiment constitute the variable throttle mechanism of the present invention, but it goes without saying that the variable throttle mechanism also includes a directional control valve.

The second embodiment shown in Fig. 2.3 has a first pilot room 1
A protrusion 27.28 is formed on the end of the spool facing the plug 29.
．． It is inserted into recesses 31 and 32 formed in 30.

As is clear from the cross-sectional view of FIG.
is formed. Further, the recesses 31.32 also have flat portions 31a, 3 corresponding to the flat portions 27a, 28a.
2a is formed.

The flat parts of the protrusions 27 and 28 and the recesses 31
．． The flat portions of the spools 11 and 32 are opposed to each other to prevent relative rotation between the two, thereby preventing the spools 11 and 12 from rotating.

Since the configuration other than the above is completely the same as that of the first embodiment, detailed explanation thereof will be omitted.

According to the second embodiment, the projections 27, 28
Since the rotation of the spool 11.12 is prevented by the action of the spool 11.12 and the recessed portions 31.32, there is no inconvenience caused by the rotation of the spool, unlike in the prior art described above.

[Brief explanation of the drawing]

FIG. 1 shows a first embodiment of the present invention, and FIG.
The figures show the second embodiment, in which Fig. 2 is a circuit diagram similar to Fig. 1, Fig. 3 is a sectional view taken along the line m-m in Fig. 2, and Fig. 4 is a circuit diagram of the conventional device. It is a circuit diagram similar to the figure. A, , A2--1.2nd actuator, vl, V2
...1.2...Pressure compensation valve, 1.2...-Next side port, 3.4...Secondary side port, 9.10-...Variable throttle constituting the variable throttle mechanism , 11.12-... Spool, 15.16-... 1st pilot room, 17.18
---Second pilot room, 27. 2 B--protrusion, 31°32--recess.

Claims (2)

[Claims] (1) While forming a primary side port leading to the pressure source and a secondary side port leading to the actuator, a spool is provided to control the flow path area between these two ports, and one end of this spool faces the first pilot chamber. The other end faces the second pilot chamber, and a variable throttle mechanism is provided between the secondary port and the actuator, and the pressure between the secondary port and the variable throttle mechanism is transferred to the first pilot chamber. guidance,
The pressure between the variable throttle mechanism and the actuator is guided to the second pilot chamber, and the spool moves so that the differential pressure before and after the variable throttle mechanism is maintained at the set value, and the pressure between the primary port and the secondary port is maintained at the set value. In a pressure compensation valve device that controls a flow path area, an annular groove is formed on the circumferential surface of the spool between the primary port and the first pilot chamber, and a communication groove is provided to communicate the annular groove with the secondary port. A pressure compensation valve device formed by forming a pressure compensation valve device. (2) While forming a primary side port leading to the pressure source and a secondary side port leading to the actuator, a spool is provided to control the flow path area between these two ports, and one end of this spool faces the first pilot chamber. The other end faces the second pilot chamber, and a variable throttle mechanism is provided between the secondary port and the actuator, and the pressure between the secondary port and the variable throttle mechanism is transferred to the first pilot chamber. guidance,
The pressure between the variable throttle mechanism and the actuator is guided to the second pilot chamber, and the spool moves so that the differential pressure before and after the variable throttle mechanism is maintained at the set value, and the pressure between the primary port and the secondary port is maintained at the set value. In a pressure compensating valve device for controlling a flow path area, a protrusion is provided on either one end of the spool or the pilot chamber, and the protrusion is fitted on the other end of the spool or the pilot chamber. A pressure compensating valve device that is provided with a recess that prevents its rotation.