JP2527253Y2 - Fluid pressure control valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a fluid pressure control valve, particularly to a back pressure control valve in a pressure oil return circuit.

[Conventional technology]

A back pressure control valve is provided in the pressure oil return circuit of the hydraulic suspension of the automobile as a measure against abnormal noise from the solenoid valve and the flow control valve, and the pressure in the return circuit is always kept high to prevent cavitation.

In the prior art, the back pressure control valve has a valve sleeve fitted and fixed to the valve housing 1 as shown in FIG. 2, and a spool 4 is fitted to the valve sleeve slidably in the axial direction. Has been inserted. The bolt-shaped cap plug screwed into the right end of the valve sleeve and integrated with the valve housing 1 and screwed into the opening at the right end of the hollow hole is hermetically closed at the opening at the right end of the hollow hole. ing.

The hollow hole is formed by a small-diameter inflow hole 21, a medium-diameter portion 22, and a large-diameter portion 23 in order from the back left to the right opening, and a drain hole 27 communicating with the oil tank T is opened in the large-diameter portion 23. doing.

The valve sleeve is formed with a middle diameter portion 31, a small diameter portion 32, and a large diameter portion 33 in this order from the left side, and the hollow portion is a middle diameter portion of a coaxial line.
A spool sliding hole 34 in the range of 31 and the small diameter portion 32 is formed,
A valve seat ring groove 37 is formed on the inner peripheral surface of the middle diameter portion 31, and a passage 39 penetrates radially toward the outer peripheral surface through an annular groove 38 formed on the inner peripheral surface in the range of the small diameter portion 32. ing.

Spool 4 slidably fitted in spool slide hole 34
An annular groove 41 is formed on the outer peripheral surface near the left end portion, a spring insertion hole 42 is formed in the axial direction from the right end surface, and a through hole 43 communicating from the bottom surface of the spring insertion hole 42 to the annular groove 41 is formed. I have.

The bolt-shaped cap is composed of a head portion 51 and a shaft portion 53, and a spring insertion hole 55 is formed in the axial direction from the tip end surface of the shaft portion 53.

The compression coil spring 6 is fitted with a preload in a spring fitting space S defined by the spring insertion hole 42 of the spool 4 and the spring insertion hole 55 of the bolt-shaped cap.

A passage 39 communicating with the annular groove 38 of the valve sleeve by the large diameter portion 23 of the hollow hole of the valve housing 1 and the small diameter portion 32 of the valve sleeve.
A passage 32a communicating with the drain hole 27 of the valve housing 1 is formed, and the annular groove 38 of the valve sleeve and the annular groove 41 of the spool 4 are formed.
Means that the positions in the axial direction substantially coincide with each other.

In this back pressure control valve, the pressure oil of the pressure oil return circuit flows through the valve housing 1 inflow hole 21, and the oil pressure is applied to the left end surface of the spool 4.

When the oil pressure is equal to or higher than the set predetermined pressure, the spool 4 retreats according to the oil pressure against the spring force of the compression coil spring 6, and the spring force of the compression coil spring 6 and the oil pressure always remain. It will be in a balanced position. Then, the end face of the spool 4 is separated from the valve seat ring 7, the annular groove 38 of the valve sleeve and the end face of the spool 4 are opened according to the displacement, and the inflow hole 21 is formed.
Is the left end of the spool slide hole 34, the annular groove 3 of the valve sleeve.
8. The pressure oil communicates with the drain hole 27 via the passage 39 and the passage 32a, and the pressure oil flows out to the oil tank T.

When the oil pressure of the pressure oil flowing into the inflow hole 21 becomes less than the set predetermined pressure, the spring force of the compression coil spring 6 overcomes the oil pressure, the spool 4 advances, and the end face of the spool 4
, The annular groove 38 of the valve sleeve and the inflow hole 21 are shut off by the spool 4, the outflow of the pressure oil to the oil tank T via the back pressure control valve stops, and the back pressure rises to a predetermined pressure. .

Thus, the back pressure of the pressure oil return circuit is always maintained at a predetermined pressure set by the spring force of the compression coil spring 6.

[Problems to be solved by the invention]

In the above-mentioned back pressure control valve, the spring fitting space S defined by the spring insertion hole 42 of the spool 4 and the spring insertion hole 55 of the bolt-shaped lid plug is enlarged or reduced by the forward and backward movement of the spool 4 in the valve operation. However, since the oil flows into and out of the drain hole 27 through the annular groove 41 of the spool 4 and the through holes 43a and 43b, there is no problem at all. When the oil enters with the oil, it is difficult to be discharged even when the oil flows out, and air accumulates in the fitting space S. As a result, the attenuation of the forward and backward vibration of the spool is insufficient, which causes the generation of abnormal noise and pressure vibration.

[Means for solving the problem]

The fluid pressure control valve according to the present invention has a valve body slidably fitted in a valve housing, a spring fitted in a spring fitting space in the valve housing to push the valve body forward, and to push the valve body backward. A spring is formed by fitting an inflow hole through which fluid flows into the valve body from the side opposite to the spring fitting space to the spring, a first passage directly connecting the inflow hole and the outflow hole, and the inflow hole and the outflow hole. The first passage and the second passage are connected to each other through the mounting space, and the first passage and the second passage are shut off from the inflow hole by the valve body at the forward position, and communicate with the inflow hole by the valve body at the backward position. It has become.

[Action]

When this fluid pressure control valve is used as a back pressure control valve in a pressure oil return circuit of a hydraulic suspension of an automobile, for example, an outflow passage of pressure oil of the pressure oil return circuit is communicated with an inflow hole, and the pressure oil is The oil is discharged to the oil tank T through the back pressure control valve.

The pressure oil of the pressure oil return circuit flows in from the valve housing inflow hole, and the oil pressure is applied to one end face of the valve body.

When the oil pressure is equal to or higher than the set predetermined pressure, the valve body retreats according to the oil pressure against the spring force of the spring, and is always at a position where the spring force of the spring and the oil pressure are balanced.
Then, the inflow hole communicates with the outflow hole through the first flow passage and the second flow passage by retreating the valve body, and the pressure oil flows out of the outflow hole.

When the oil pressure of the pressure oil to the inflow hole becomes less than the set predetermined pressure, the spring force of the spring overcomes the oil pressure, the valve body moves forward, and the inflow hole is moved by the valve body in the advanced position to the first flow passage and the second passage. The flow path 2 is shut off, the outflow of the pressure oil via the back pressure control valve stops, and the back pressure rises to a predetermined pressure.

Thus, the back pressure of the pressure oil return circuit is always maintained at a predetermined pressure set by the spring force of the spring.

The spring fitting space is enlarged or reduced by the forward and backward movement of the valve body in the above-described valve operation, but when the valve body is at the retracted position, oil from the inflow hole flows through the fitting space in the second flow passage. It flows in one direction to the outlet. Therefore, air bubbles do not stay in the spring fitting space.

〔Example〕

 An embodiment of the present invention will be described with reference to the drawings.

In addition, up, down, left and right in the following description are directions in FIG.

In FIG. 1, a valve sleeve is fitted and fixed in a hollow hole of a valve housing 1 of a fluid pressure control valve, and a spool 4 is further fitted in the valve sleeve so as to be slidable in the axial direction. The bolt-shaped cap plug screwed to the right end of the valve sleeve and screwed into the right end opening of the hollow hole and attached to the valve housing 1 hermetically closes the right end opening of the hollow hole.

To describe in more detail, the hollow holes are sequentially smaller in diameter from the left side to the right side opening, the small-diameter inflow hole 21, the middle-diameter portion 22, the large-diameter portion 23,
The large-diameter portion 23 and the annular groove 24 are formed with an annular groove 24, a screw hole 25, and a packing seat 26, and have drain holes 27, 28 communicating with the oil tank T.

The valve sleeve is formed with a middle diameter portion 31, a small diameter portion 32, and a large diameter portion 33 in this order from the left side, and the hollow portion is a middle diameter portion of a coaxial line.
Spool sliding hole 34 and large diameter portion 33 in the range of 31 and small diameter portion 32
The O-ring groove 36 is formed on the outer peripheral surface of the middle diameter portion 31, the valve seat ring groove 37 is formed on the inner peripheral surface, and the small-diameter portion 32 An annular groove 38 formed in the inner peripheral surface of the range has a passage 39 penetrating radially in the outer peripheral surface.

Spool 4 slidably fitted in spool slide hole 34
An annular groove 41 is formed on the outer peripheral surface near the left end portion, a spring insertion hole 42 is formed in the axial direction from the right end surface, and a bottomed through hole 43a in the axial direction from the bottom surface of the spring insertion hole 42 and the through hole 43a. Hole 4
A radial through hole 43b communicating from 3a to the annular groove 41 is formed.

The bolt-shaped cap is composed of a head portion 51, a shaft portion 53 having a male screw portion 52 formed at a distal end portion, and a large-diameter screw portion intermediate the head portion 51 and the shaft portion 53.
54, and a spring insertion hole 55
However, through holes 56 are formed in the radial direction, which are opened from the spring insertion holes 55 to the outer peripheral surface of the shaft portion 53.

Describing the assembling structure of the fluid pressure control valve, the male screw portion 52 of the bolt-shaped cap is screwed into the screw hole 35 of the valve sleeve, the two are integrated, and the spool 4 slides into the spool sliding hole 34 of the valve sleeve. They are freely fitted. At this time, the compression coil spring 6 is fitted with a preload into the spring fitting space S defined by the spring insertion hole 42 of the spool 4 and the spring insertion hole 55 of the bolt-shaped lid plug, and the valve seat ring groove 37 is provided. The tip end surface of the spool 4 abuts against the valve seat ring 7 fitted in the oil seal to maintain oil tightness.

The above-described assembly structure of the valve sleeve, the spool 4 and the bolt-shaped cap is incorporated in a hollow hole of the valve housing 1. That is, the medium diameter portion 31 and the large diameter portion 33 of the valve sleeve are fitted to the medium diameter portion 22 and the large diameter portion 23 of the hollow hole of the valve housing 1,
A large-diameter screw portion 54 of a bolt-shaped cap is screwed into the screw hole portion 25 of the hollow hole of the valve housing 1. At this time, the O-ring groove 36
The O-ring 8 fitted to the valve housing 9 and the packing 9 fitted to the packing seat 26 maintain the sealing performance of the back pressure control valve in the assembled configuration, and furthermore, the large diameter portion 23 of the hollow hole of the valve housing 1.
And the small diameter portion 32 of the valve sleeve, the annular groove 38 of the valve sleeve
A passage 32a is formed which communicates a passage 39 communicating with the valve housing 1 and the drain hole 27 of the valve housing 1, and a through hole 56 of the bolt-shaped cap is formed through the annular groove 24 of the valve housing 1 through the drain hole 28.
The annular groove 38 of the valve sleeve and the annular groove of the spool 4
41 and the position in the axial direction substantially coincide with each other.

A first flow passage communicating the inflow hole 21 and the drain hole 27 is formed by the annular groove 38, the passage 39, and the passage 32a, and a second flow passage communicating the inflow hole 21 and the drain hole 28 is formed. , The annular groove 38, the annular groove 41, the through holes 43a and 43b, the spring fitting space S, the through hole 56, and the annular groove 24.

 The operation and action of the fluid pressure control valve will be described.

This fluid pressure control valve is used as a back pressure control valve in a pressure oil return circuit of a hydraulic suspension of an automobile, for example.
The pressure oil outflow passage of the pressure oil return circuit is communicated with the inflow hole 21, and the pressure oil is discharged to the oil tank T through the back pressure control valve.

The pressure oil of the pressure oil return circuit flows from the inflow hole 21 of the valve housing 1, and the oil pressure is applied to the left end surface of the spool 4.

When the hydraulic pressure is equal to or higher than the set predetermined pressure, the spool 4 retreats (displaces rightward) according to the magnitude of the hydraulic pressure against the spring force of the compression coil spring 6, and always moves the compression coil spring 6.
At a position where the spring force and the hydraulic pressure are balanced. Then, the end face of the spool 4 is separated from the valve seat ring 7, the annular groove 38 of the valve sleeve and the end face of the spool 4 are opened in accordance with the displacement thereof, and the inflow hole 21 is formed at the left end of the spool sliding hole 34 by the valve sleeve. Through the annular groove 38, the passage 39 and the passage 32a.
And the pressure oil flows out to the oil tank T.

When the oil pressure of the pressure oil flowing into the inflow hole 21 becomes less than the set predetermined pressure, the spring force of the compression coil spring 6 overcomes the oil pressure, the spool 4 advances (displaces leftward), and the end face of the spool 4 7 and the annular groove 38 of the valve sleeve and the inflow hole
21 is shut off by the spool 4, the outflow of the pressure oil to the oil tank T via the back pressure control valve stops, and the back pressure rises to a predetermined pressure.

Thus, the back pressure of the pressure oil return circuit is always maintained at a predetermined pressure set by the spring force of the compression coil spring 6.

Due to the forward and backward movement of the spool 4 in the above valve operation,
The spring fitting space S is enlarged or reduced. However, since the spring fitting space S communicates with the drain hole 27 through the annular groove 41 of the spool 4 and the through holes 43a and 43b, there is no problem because oil flows in and out. At the time of retreat, the annular groove 41 of the spool 4 and the through holes 43a, 43
b, the spring fitting space S, the through hole 56 of the bolt-shaped cap, the annular groove 24 and the drain hole 28 of the valve housing 1 constitute one flow passage,
Part of the pressure oil from the inflow hole 21 passes through the flow passage and
Leaked to Therefore, air bubbles do not stay in the spring fitting space S.

This back pressure control valve can be used as a relief valve.

In this case, the upstream side of the inflow hole 21 of the valve housing 1 is branched and connected to a fluid supply passage from a fluid supply source.

As will be easily understood from the above description of the operation, when used as a relief valve, the fluid pressure of the pressurized fluid supplied to the supply passage is maintained at a predetermined pressure or less.

[Effect of the invention]

According to the fluid pressure control valve of the present invention, the inflow hole and the outflow hole are communicated / blocked by the forward / backward movement of the valve body in the opening / closing operation of the valve for pressure control, and the predetermined pressure is maintained. In the retracted position of the valve element, the inflow hole communicates with the outflow hole via the first flow passage and the second flow passage. At this time, the pressure oil flowing in the second flow passage flows in the spring fitting space in one direction to the outflow hole, so that the air bubbles do not stay in the spring fitting space.

Therefore, since no air bubbles accumulate in the spring fitting space, the occurrence of abnormal noise and pressure vibration is prevented without damping forward and backward vibration of the valve element.

In addition, since the flow passage corresponding to the total flow rate of the pressure oil is formed by the direct first flow passage in addition to the second flow passage in which the spring fitting space is interposed, the valve device has a structure. It is possible to avoid an increase in size. Since the air flows through the outlet hole, the air bubbles do not stay in the spring fitting space.

Therefore, since no air bubbles accumulate in the spring fitting space, the occurrence of abnormal noise and pressure vibration is prevented without damping forward and backward vibration of the valve element.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a back pressure control valve according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of a back pressure control valve according to the prior art. 1: Valve housing, 4: Spool, 21: Inflow hole, 22, 31: Medium diameter portion, 23, 33: Large diameter portion, 24, 41: Annular groove, 25: Screw hole, 26: Packing seat, 27 , 28: drain hole, 32: small diameter part, 34: spool sliding hole, 35: screw hole, 36: O-ring groove, 37: valve seat ring groove,
38: annular groove, 39: passage, 42: spring insertion hole, 43a, 43b: through hole, 5
1: Head, 52: Male thread, 53: Shaft, 54: Large diameter thread, 55: Spring insertion hole, 56: Through hole, 6: Compression coil spring, 7: Valve seat ring, 8: O-ring, 9: Packing, S: Spring insertion space

Claims (1)

(57) [Scope of request for utility model registration] 1. A valve body slidably fitted in a valve housing, a spring fitted in a spring fitting space in the valve housing to push the valve body forward, and a valve body to push the valve body backward. On the other hand, an inflow hole through which fluid flows in from the side opposite to the spring fitting space and facing the spring, a first flow passage directly connecting the inflow hole and the outflow hole, and the inflow hole and the outflow hole are formed in the spring fitting space. The inflow hole is cut off from the first flow passage and the second flow passage by the valve body at the forward position, and the first flow passage and the second flow passage are closed by the valve body at the retreat position. A fluid pressure control valve adapted to communicate with the second flow passage.