JPS6135823Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a hydraulic pressure control valve such as a relief valve for hydraulic control or a bypass type pressure compensating valve.

Prior Art Conventionally, this type of hydraulic control valve generally has 1
The liquid flowing from the primary port side to the secondary port side is narrowed between the poppet part at one end of the spool and the valve seat, which is slidably fitted into the valve chamber provided in the main body that has the secondary port and the secondary port. A variable throttle section is provided through which the flow passes as a flow that converges toward the axis of the spool, and the opening area of the variable throttle section is controlled by the operation of the spool to reduce the pressure in the primary port chamber on the primary port side. A control system is well known (Hydraulic Technology Handbook, January 30, 1980, Nikkan Kogyo Shimbun, P390, Figures 3 and 40).

However, in such a liquid pressure control valve, the liquid flowing through the variable restrictor becomes narrow and the flow becomes narrow, so as is well known, unstable phenomena such as chattering occur, and cavitation occurs, causing noise and vibration. The problem is that it is easy to do.

Purpose of the invention Therefore, the purpose of this invention is to eliminate the above-mentioned problems, and to develop a hydraulic system that stabilizes the operation, prevents cavitation, and prevents the occurrence of noise, vibration, etc. The objective is to provide a new control valve.

Summary of the invention Therefore, the structure and operation of this invention is such that the pressure control section of the spool is composed of a first pressure control section and a second pressure control section that are spaced apart from each other at a constant interval in the axial direction of the spool, The variable throttle part formed between the control part and the peripheral wall of the valve chamber is composed of a first variable throttle part and a second variable throttle part which are spaced apart from each other at a constant distance in the axial direction, and By allowing the liquid to flow into the port through the first and second variable throttle sections, which are two-stage throttles, while reducing the pressure in stages, it is possible to prevent cavitation from occurring. The outer diameter of the first intermediate chamber formed between the second variable throttle part and the barrier is configured to be larger than the outer diameter of the first variable throttle part, and the second intermediate chamber formed between the second variable throttle part and the barrier. By configuring the outer diameter of the variable throttle part to be larger than the outer diameter of the second variable throttle part, the fluid flowing through the first and second variable throttle parts from the primary port side to the secondary port side becomes a divergent flow. In this way, the hydraulic pressure control valve is stabilized, and the second variable throttle part opens before the first variable throttle part opens, and the opening area of the first variable throttle part is larger than that of the second variable throttle part. The dimensions are configured so that the area is always larger than the opening area of the spool at any stroke position of the spool, and the barrier is provided with a plurality of through holes that serve as fixed throttles to gradually flow the fluid from the primary port to the secondary port. It is characterized in that it is further stabilized and cavitation is less likely to occur by allowing it to flow smoothly without any stagnation while reducing the pressure.

Embodiments Hereinafter, this invention will be explained in detail with reference to illustrated embodiments.

In FIG. 1, 1 is a pump, 2 is a main valve as an example of a hydraulic control valve, and 3 is a pilot relief valve.
This constitutes a so-called balanced piston type relief valve.

4 is the primary port P and secondary port T of the main valve 2
5 is a sleeve fitted into the main body 2, 6 is a spool slidably fitted into the valve chamber 7 in the sleeve 5, and 8 is formed at one end of the spool 6 so as to communicate with the vent port V. 10 is a primary port chamber formed at the other end of the spool 6 so as to communicate with the primary port P, and the spool 6 is connected to the primary port chamber 10 with the spring It moves forward and backward in the axial direction depending on the pressure difference with the chamber 8.

Further, 11 is a poppet-shaped first pressure control section provided at the tip of the spool 6 on the primary port chamber 10 side;
12 is a valve seat having a conical surface provided on the peripheral wall of the valve chamber 7 so as to face the first pressure control part 11; 13 is a first variable valve seat formed between the first pressure control part 11 and the valve seat 12; A constriction part 15 is a second pressure control part provided on the spool 6 so as to be spaced from the first pressure control part 11 in the axial direction by a groove 16, and 17 is a part 18 of the peripheral wall of the valve chamber 7 and a second pressure control part. A second variable throttle part is formed between the control part 15 and controls the opening degrees of the first and second variable throttle parts 13 and 17 by the operation of the spool 6, thereby controlling the openings of the primary ports P and 2. The opening degree between the port and the next port T is controlled.

Further, 21 is formed between the first variable aperture part 13 and the second variable aperture part 17, and the first variable aperture part 1
3, the liquid flowing from the first variable constriction section 13 to the second intermediate chamber 21 is connected to the tapered peripheral wall section 2 of the first intermediate chamber 21.
The flow is expanded while being guided by 1a, that is, the flow diverges in a conical shape from the axial direction of the spool.

Further, 22 is a second pressure control section 15 of the spool 6.
A barrier 23 is formed by a part of the sleeve 6 provided between the second variable throttle part 17 and the secondary port T so as to surround the outer periphery of the second variable throttle part 17 and the secondary port T at regular intervals. A second intermediate chamber 24 is formed between the barrier 23 and has a larger outer diameter than the second variable throttle part 17, and 24 is a plurality of through holes provided in the barrier 23 at equal intervals on the circumference. The liquid flowing from the variable throttle section 17 to the second intermediate chamber 23 is configured to spread out.

Even when the first pressure control section 11 and the valve seat 12 are in close contact with each other and the first variable throttle section 13 is in a fully closed state,
The dimensions of the spool 6 and the sleeve 7 are configured so that the second variable throttle part 17 opens slightly, and furthermore, at any stroke position of the spool 6, the opening area of the second variable throttle part 17 is equal to the opening area of the first variable throttle part 13. The dimensions are configured so that it is always larger than the area.

On the other hand, the second intermediate chamber 23 and the secondary port T are communicated through a through hole 24 and a passage 25,
The primary port chamber 10 and the spring chamber 8 are communicated through a passage 27 provided with a vent throttle 26, and the hydraulic pressure of the primary port 10 is guided to the non-spring chamber side of the flange 28 of the spool 6 through a passage 29.

Note that 33 is a presser flange, and 34 is a bolt.

Pump port P of main valve 2 above is main line 3
0 to the pump 1, the secondary port T to the tank 31, and the vent port V to the pilot relief valve 3.

Now, in the hydraulic pressure control valve configured as described above, if the pressure in the primary port chamber 10, that is, the main line 30 is lower than the set pressure of the pilot relief valve 3, the pilot relief valve 3 to which that pressure is transmitted closes. The pressures in the primary port chamber 10 and the spring chamber 8 become the same. Therefore, the spring 9 in the spring chamber 8
Due to the spring force, the spool 6 is positioned downward in FIG. 1, brings the first pressure control section 11 into close contact with the valve seat 12, and closes the first variable throttle section 13.

On the other hand, the pressure in the primary port chamber 10 increases,
When the pilot relief valve 3 to which the pressure is transmitted opens, a vent flow is formed that flows from the primary port chamber 10 to the pilot relief valve 3 via the passage 27, the vent throttle 26, and the spring chamber 8. Therefore, a pressure difference equal to the pressure difference across the vent throttle 26 is generated between the pressure in the primary port chamber 10 and the pressure in the spring chamber 8, and the spool 6 moves forward and backward in the axial direction in accordance with this pressure difference. The first and second variable aperture parts 1
3 and 17 are opened and closed to discharge excess liquid to the tank 31, and the pressure in the primary port chamber 10 is controlled to be higher than the set pressure of the pilot relief valve 3 by an amount equivalent to the spring pressure of the spring 9.

The surplus liquid is transferred to the first, which is a two-stage variable throttle.
The flow rate is controlled by the second variable throttle parts 13 and 17, and the tank 3
1, the pressure is reduced in stages, and cavitation is therefore prevented.

Furthermore, since the outer diameter of the first intermediate chamber 21 is larger than the outer diameter of the first variable throttle section 13, the excess liquid flowing from the first variable throttle section 13 to the first intermediate chamber 21 becomes a spreading flow, and similarly, Since the outer diameter of the second intermediate chamber 23 is larger than the outer diameter of the second variable throttle section 17, the excess liquid flowing from the second variable throttle section 17 to the second intermediate chamber 23 becomes a spreading flow. Therefore, the operation of the spool is stable.

Furthermore, the second variable diaphragm part 17 is opened even when the first variable diaphragm part 13 is closed, and the opening area of the second variable diaphragm part 17 is larger than the opening area of the first variable diaphragm part 13. 6, the excess liquid is smoothly discharged into the tank 31 through the first and second variable throttle portions 13 and 17 without any stagnation.

The hydraulic control valve 2 as a modified example shown in FIG.
It is used as a bypass type pressure compensating valve that controls the differential pressure before and after the variable throttle valve 35 to be constant. The structure of this hydraulic pressure control valve 2 is substantially the same as that shown in FIG. 1, and the only difference is that it does not include a vent passage 27 and a vent throttle 26.

Furthermore, in each of the above embodiments, the first pressure control section 11
is configured in a poppet shape, but the second pressure control section 1
5, it may be constructed by the land portion of the spool.

Effects of the invention As is clear from the above explanation, according to this invention, the variable throttle section is composed of two stages, the first variable throttle section and the second variable throttle section, which are spaced apart from each other at a constant distance in the axial direction of the spool. , excess liquid can be discharged while being depressurized step by step, and cavitation can therefore be prevented from occurring. Furthermore, since the outer diameter of the first intermediate chamber is larger than the outer diameter of the first variable throttle section, and the outer diameter of the second intermediate chamber is larger than the outer diameter of the second variable throttle section, The liquid flowing from the first variable throttle part to the first intermediate chamber and the liquid flowing from the second variable throttle part to the second intermediate chamber can be made into divergent flows, so that the hydraulic pressure control valve can be stabilized. can. Furthermore, the second variable diaphragm section is configured to open before the first variable diaphragm section opens, and the opening area of the second variable diaphragm section 17 is always larger than the opening area of the first variable diaphragm section. Due to the dimensional structure, the excess fluid can be gradually reduced in pressure in stages and flowed smoothly without any hitch, thereby stabilizing the operation of the hydraulic pressure control valve and preventing the occurrence of cavitation.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a hydraulic pressure control valve according to an embodiment of this invention, and FIG. 2 is a circuit diagram of a modified example used as a bypass type pressure compensation valve. 2...Liquid pressure control valve, 4...Main body, 6...Spool, 13...First variable throttle section, 17...Second variable throttle section, 21...First intermediate chamber, 23...Second intermediate chamber Room.

Claims (1)

[Utility Model Claims] A hydraulic pressure control valve in which a spool is slidably fitted into a valve chamber provided in a body having a primary port and a secondary port, a spring chamber with a compressed spring is formed at one end of the spool, while a primary port chamber communicating with the primary port is formed at the other end of the spool, and the spool is advanced and retreated in accordance with the pressure difference between the primary port chamber and the spring chamber, thereby controlling the opening and closing of a variable throttle portion between the pressure control portion of the spool and the peripheral wall of the valve chamber to open and close the primary port and secondary port, the pressure control portion being divided into a first pressure control portion 11 and a second pressure control portion 22 spaced from each other by a fixed distance in the axial direction of the spool.
The variable throttle section is composed of a first variable throttle section 13 and a second variable throttle section 17 which are spaced apart from each other in the axial direction of the spool. The outer diameter of a first intermediate chamber 21 formed between the first variable throttle section 13 and the second variable throttle section 17 is made larger than the outer diameter of the first variable throttle section 13.
The liquid flowing to the second port T1 is made to diverge, and a barrier 22 surrounding the spool 6 at a fixed interval is formed between the second variable throttle portion 17 and the secondary port T
Between the second variable throttle portion 17 and the barrier 22
The outer diameter of the second intermediate chamber 23 formed between the second variable throttle portion 17 and the second variable throttle portion 17 is set to be larger than the outer diameter of the second variable throttle portion 17,
A hydraulic control valve characterized in that the liquid flowing from the second variable throttling section 17 to the second intermediate chamber 23 becomes an expanding flow, the second variable throttling section 17 opens before the first variable throttling section 13 opens, and the opening area of the second variable throttling section 17 is dimensioned to be always larger than the opening area of the first variable throttling section 13 at any stroke position of the spool 6, and further characterized in that the barrier wall 22 is provided with a plurality of through holes 24 which serve as fixed throttlings.