JPH03213778A - Pressure control valve - Google Patents

Abstract

PURPOSE:To facilitate the change operation of the set pressure and control the pressure accurately by interposing a steel sphere between a cylindrical part of a spool and a piston. CONSTITUTION:A primary side flow passage 11b, a secondary side flow passage 11c, a large diameter engagement hole 11a where both the flow passages 11b, 11c are communicated, and a pilot flow passage 11d are provided in a housing 11. A spool 16 is engaged in the engagement hole 11a freely to slide, and a small diameter cylindrical part 16d to be engaged in a small diameter engagement hole 15a provided in a lower cover 15 is projected in the lower end of the spool 16. Furthermore, a piston 23 and a steel sphere 24 are engaged in the small diameter engagement hole 15a freely to slide. A spring 21 is provided in the spool 16, and an adjusting screw 20 for adjusting the energizing force thereof is engaged in the spool 16 freely to progress and go back. The working force applying to the piston 23 on the basis of the pressure of the primary side flow passage 11b is thereby made to work on the cylindrical part 16d of the spool 16 through the sphere 24.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a pressure control valve that generates flow from a primary flow path to a secondary flow path when the pressure in a pilot flow path reaches a set value.

(Prior art) As shown in FIG. 2, this type of pressure control valve is slidably fitted into a large-diameter fitting hole 1a provided in the valve body 1, and is fitted in a primary side flow hole 1a provided in the valve body 1. A spool 2 that connects or blocks the path 1b and the secondary flow path 1c, a spring 3 that urges the spool 2 downward to disconnect between the primary flow path 1b and the secondary flow path 10, and the urging force of the spring 3. A small-diameter screw 4 that protrudes from the lower end of the spool 2 is slidably fitted into a small-diameter fitting hole 1d connected to the large-diameter fitting hole 1a. A piston 5 facing the cylindrical portion 2a is provided, and the downstream flow path 1b and the fitting hole 1d are communicated via the pilot flow path 1e.

According to the pressure control valve having such a configuration, when the pressure in the downstream flow path 1b reaches the set value set by the anoyast screw 4, the piston 5 resists the biasing force of the spring 3 and moves the spool 2. is pushed upward, and the downstream flow path 1b and the secondary flow path 1c are electrically connected.

(sJ!I to be solved by the invention) In the conventional pressure control valve described above, since the cylindrical part 2a protruding from the lower end of the spool 2 is in pressure contact with the upper end of the piston 5, it is necessary to change the set pressure. 7. When the adjustment screw 4 is turned, the spool 2 is difficult to rotate together with the spring 3, and a considerably large force is required to rotate the adjustment screw 3, making it difficult to change the set pressure.

Furthermore, if the lower end of the cylindrical portion 2a of the spool 2 and the upper end of the piston 5 do not contact each other accurately and at right angles, the spool 2 may operate tilted, resulting in unstable operation. Therefore,
- The outgoing channel 1b changes from an unpressurized state to a pressurized state, and a flow is generated from the primary channel 1b to the secondary channel 1c, and then the primary channel 1b changes from an unpressurized state to a pressurized state again. When the flow is repeatedly generated from the primary flow path to the secondary flow path 1c, the pressure at which the flow is generated fluctuates as shown in FIG. 3, resulting in poor repeatability.

SUMMARY OF THE INVENTION In view of these problems, it is an object of the present invention to provide a pressure control valve that allows easy change of set pressure and accurate pressure control.

(1! Means for Solving the Problem) In order to achieve the above-mentioned object, the present invention provides a large-diameter fitting hole in which a downstream side flow path and a secondary side flow path communicate with each other, and a connection to the large-diameter fitting hole. The valve body has a small-diameter fitting hole and a pilot flow path that communicates between the small-diameter fitting hole and the primary flow path, and one end of the spool that slidably fits into the large-diameter fitting hole. A small-diameter cylindrical part that protrudes and fits loosely into the small-diameter fitting hole, a piston that slidably fits into the small-diameter fitting hole, and a piston that can freely slide into the small-diameter fitting hole between the piston and the cylindrical part. It is equipped with a steel ball that fits, a spring that biases the spool in the direction of connecting the primary flow path and the secondary flow path, and a seven-point screw that adjusts the biasing force of the spring, and acts on the piston. The spool is characterized in that the acting force based on the pressure in the primary flow path acts on the cylindrical portion of the spool via the steel ball.

(Operations and Effects of the Invention) According to the above configuration, since the steel ball is interposed between the cylindrical portion of the spool and the piston, the spool and spring are easily rotated together when changing the set pressure, making operation easier. In addition, since the force is transmitted between the spool and the piston via the steel balls, the force is easily applied to the spool and the piston, allowing accurate pressure control.

(Example) Examples of the present invention will be described below based on the drawings.
The figure shows a pressure control valve according to an embodiment of the invention. The pressure control valve has a valve body 10;
It consists of a housing 11 and an upper cover 14 and a cover 15 that are fluid-tightly attached to both upper and lower ends of the housing 11 via O-rings 12, 13, and 22, respectively.

The housing 11 is provided with a primary flow path 11b, a secondary flow path 11c, and a pilot flow path lid that communicate with the large-diameter fitting hole 11a1, and the spool 16 can freely slide into the fitting hole 11a. is mated to.

When the spool 16 is at the lowest position, the primary flow path 11
A land portion 16a that connects the land portion 16a and the secondary flow path, and both flow paths 11b formed below and adjacent to the land portion 16a when the spool 16 slides upward.

An annular groove 16b is provided to communicate between the two.

In addition, there is a spring housing hole 16c that opens at the upper end.
is provided. Furthermore, a small diameter cylindrical portion 16d protrudes from the lower end of the spool 16 and is loosely fitted into a small diameter fitting hole 15a provided in the lower cover 15. Then, a small hole 16e and a columnar part 1 are formed downward from the bottom of the spring housing hole 16e.
A small hole 16f is provided in the radial direction of 6d.

On the other hand, the upper cover 14 has a storage hole 14a and a screw hole 1.
4b, a spring receiver 17 having an O-ring 18 and a vertical spring guide 17m is slidably fitted in the accommodation hole 14a, and a lock nut 19 is fitted in the screw hole 14b. The strike screw 20 is screwed together so that it can move forward and backward. A fill spring 21 is housed in the housing hole 14a and the spring housing fold hole 16c.

The lower cover 15 is provided with a pilot flow path 15b,
A piston 23 and a steel ball 24 are slidably fitted into the fitting hole 15a. Further, when the spool 16 is at the lowest position, a gap S is ensured. Note that 25.26 is a circle.

This embodiment has the above-mentioned configuration, and the lock nut 19 is loosened and the adjustment screw 20 is turned to tighten the spring receiver 1.
When 7 is slid downward, the spring 21 contracts, the biasing force increases, and the pressure setting increases 1IIW! 1 will be given.

When the pressure of the fluid flowing into the downstream flow path 11b reaches a set value, the spool 16 is pushed up by the piston 23 via the steel ball 24 against the biasing force of the spring 21. Thereby, the primary side flow path 11b and the secondary side flow path 11c are electrically connected via the annular groove 16b, and the primary side flow path 11b
The fluid flows from there to the secondary flow path 11c.

Note that the fluid leaking from the outer circumferences of the spool 16 and the piston 23 is discharged to the outside through the passage from the receiving hole 14a.

According to this embodiment, the cylindrical portion 16 of the spool 16
Since the steel ball 24 is interposed between d and the piston 23,
When turning the adjuster screw 20 to change the set pressure, the spool 16 and spring 21 are easily rotated together, the spring 21 is less likely to be torsionally deformed, and the force required to turn the adjuster screw 17 is small, allowing the set pressure to be changed. Change operations become easier.

In addition, since the force between the piston 23 and the spool 16 is transmitted through the single ball 24, even if the facing surfaces of the piston 23 and the cylindrical portion 16d of the spool 16 are inclined, the force acts on the spool 16 with care. do. Therefore, spool 1
6 and the piston 23 can be prevented from operating in a tilted manner, and the spool 14 and the piston 20 can slide smoothly. Therefore,
Fluctuations in the set pressure can be prevented, allowing accurate pressure control.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a pressure control valve according to an embodiment of the present invention, FIG. 2 is a sectional view showing a conventional pressure control valve, and FIG. 3 is an explanatory diagram of the operation of the conventional pressure control valve. 10...Valve body, 11...Havenong, lla...
・Large diameter fitting hole, lid... pilot flow path, 14・
・・Upper cover, 15・・Lower cover 15a・・
・Small diameter fitting hole, 15b...Pilot channel, 20・
・・7 No Yast Screw, 21・Spring, 2
3... Piston, 24... Steel ball.

Claims (1)

[Claims] A large-diameter fitting hole where the primary side flow path and the secondary side flow path communicate, a small-diameter fitting hole connected to the large-diameter fitting hole, and a communication between the small-diameter fitting hole and the primary side flow path. A valve body with a pilot flow path, a small-diameter cylindrical part protruding from one end of a spool that slidably fits into a large-diameter fitting hole, and a small-diameter cylindrical part that fits loosely into a small-diameter fitting hole, and a small-diameter fitting hole. A piston that slidably fits into the hole, a steel ball that slidably fits into the small diameter fitting hole between the piston and the cylindrical part, and a spool that blocks the primary flow path and the secondary flow path. The spool is equipped with a spring that biases the spool in the direction of the spool, and an adjustment screw that adjusts the biasing force of the spring, and the acting force based on the pressure of the primary flow path that acts on the piston acts on the cylindrical part of the spool through the steel ball. A pressure control valve characterized by: