JPH08135608A - Pressure control valve - Google Patents

Abstract

PURPOSE: To lighten a pressure control valve by making it of aluminum, and also stably fix excellently in positioning accuracy an iron-made seat member to an aluminum-made spool. CONSTITUTION: A cylinder part 17c, having a diameter smaller than that of the slide part 17d of a spool, is formed on a spool 17 end part on a pressure chamber 5 side, and also a distortion buffering part 17e, having thickness thicker than that of the cylinder part 17c, is formed between the cylinder part 17c and the slide part 17d. Also, a seat member 18, wherein a caulking groove 19 is formed on an outer peripheral surface, is pressed in a valve hole 17a, and then the cylinder part 17c corresponding to the caulking groove 19 is caulked to be bitten into the caulking groove 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates mainly to a pressure control valve used for supplying pressure oil to a power steering device,
In particular, the present invention relates to a pressure control valve whose weight is reduced by making the device aluminum.

[0002]

2. Description of the Related Art FIG. 3 shows a sectional view of a conventional pressure control valve. A pump port P and a bypass port B are formed on the aluminum body 1. Further, a spool hole 2 is formed in the body 1, and an aluminum spool 3 is slidably incorporated in the spool hole 2. Then, the opening degree connecting the pump port P and the bypass port B changes according to the movement amount of the spool 3.
The connector 4 is inserted into one end of the spool hole 2 and the pump port P side, while the through hole 4 formed in the connector 4
a is connected to the power steering device. That is,
In this device, this connector 4 constitutes an actuator port. At the other end of the spool hole, the spool 3 and the spool hole 2 are combined to form a pressure chamber 5, and the pressure chamber 5 is provided with a spring 6 so that the spring force acts on the spool 3. .

In the middle of the through hole 4a in the connector 4,
A member 7 is provided. The rod 8 fixed to the spool 3 penetrates the communication hole 7a formed in the member 7. That is, the communication hole 7a and the rod 8 constitute the variable orifice 9. The pressure oil on the downstream side of the variable orifice 9 is supplied to the pressure sensing passage 11, the passage 10,
It is guided to the pressure chamber 5 through an oil passage formed by the small holes 12. Further, on the pressure chamber 5 side of the spool 3, a valve hole 3a is formed in the axial direction, and a cylindrical portion 3c having a diameter smaller than that of the sliding portion 3d of the spool is formed.
In the valve hole 3a, a spring 13,
A relief valve including a ball support 14, a steel ball 15 and an iron seat member 16 is provided.

Next, the operation of this device will be described. The discharge oil from a pump (not shown) passes through the variable orifice 9 from the pump port P, its flow rate is reduced, and is supplied to a power steering device (not shown) through the through hole 4a. At this time, this pressure oil flow causes a pressure difference before and after the variable orifice 9. The upstream pressure is at the right end of the spool 3 in the figure, and the downstream pressure is at the spool 3 via the oil passage. It acts on the end portion on the pressure chamber 5 side. As the rotation speed of the pump P increases, the pressure difference before and after the variable orifice 9 increases, and the pressure difference causes the spool 3 to move to the spring 6
Move to the left in the figure against. When the amount of movement increases, the opening degree that allows the pump port P and the bypass port B to communicate with each other also increases, and a larger amount of surplus flow is released from the bypass port B. However, when the load pressure on the side of the through hole 4a rises, such as when the steering wheel is stationary, the pressure on the side of the pressure chamber 5 also rises accordingly, so the spool 3 returns to the right in the drawing, and the pump port P The opening degree of the communication path with the bypass port B is reduced. In other words, this spool 3 changes in accordance with the load pressure on the steering device side.
The required flow rate is supplied to the steering device side, and the surplus flow rate is released from the bypass port.

A relief valve is provided in the valve hole 3a. The oil supplied to the power steering device, that is, the pressure oil in the pressure chamber 5 passes through the small through hole 16a in the seat member 16, and the hydraulic pressure acts on the steel ball 15 seated on the seat surface 16b. Then, when the load on the power steering device side increases and the hydraulic pressure becomes higher than the set relief pressure, the pressure oil pushes open the steel ball 15, and passes through the small through hole 3b in the spool 3 to bypass port. Missed by B. The relief pressure is set by the spring force of the spring 13.
When the relief valve opens and the pressure oil is released to the bypass port B, the pressure in the pressure chamber 5 sharply drops. As a result, the spool 3 largely moves in the leftward direction in the drawing, so that a large amount of pressure oil from the pump is released to the bypass port B and the pressure of the oil supplied to the power steering device is prevented from further increasing.

In the pressure control valve as described above, the body 1 and the spool 3 are made of aluminum in order to reduce the weight thereof. However, the steel ball 15 and the seat member 16 need to be made of iron, which is a hard material, in consideration of their durability. When the materials are different, the expansion rates thereof are different. Therefore, when the temperature of each member becomes high due to the influence of the oil temperature, the inner diameter of the hole 3a in the aluminum spool 3 becomes larger than the outer diameter of the sheet member 16. I will end up. Therefore, if the sheet member 16 is simply press-fitted into the hole 3a, the sheet member 16 may be displaced at a high temperature or, in an extreme case, may be removed from the hole 3a. If the seat member 16 shifts in this way, the set length of the spring 13 changes, which causes a problem that the relief pressure also changes. . Therefore, conventionally, a method of inserting and fixing the sheet member 16 into the spool 3 by a screw method has been adopted. That is, spool 3
The end of the valve hole 3a formed in the above is threaded. Then, after the spring 13, the ball support 14, and the steel ball 15 are provided in the hole 3a, the seat member 16 similarly threaded is inserted into the valve hole 3a by a screw method so that the seat member 16 is fixed. are doing.

[0007]

In the pressure control valve having such a structure, the iron seat member is threadably inserted and fixed in the valve hole as described above. Therefore, depending on the final tightening position of the spring 13, This will affect the amount of deflection, which in turn will affect the set pressure of the relief valve. Moreover, in the case of a screw, the final tightening position varies depending on the product, and there is a problem that the set pressure of the relief valve becomes unstable. Further, in order to solve this problem, an adjusting member such as a shim may be interposed between the seat member and the spool. However, even if the adjusting member is interposed, the adjustment actually takes time, and there is a problem that automation in a mass production line is difficult. Furthermore, there is a problem in that the sheet member needs to be screwed, resulting in a high processing cost, and at the same time, the sheet member cannot be manufactured by an inexpensive method such as sintering, resulting in a high component cost. An object of the present invention is to provide a pressure control valve capable of stably fixing an iron seat member to an aluminum spool with high positioning accuracy and at the same time while achieving weight reduction by making the device aluminum. Is.

[0008]

SUMMARY OF THE INVENTION The present invention is an aluminum body having a pump port and a bypass port formed therein,
A spool hole formed in the body, an aluminum spool that is slidably installed in the spool hole, and connects the pump port and the bypass port according to the amount of movement, and an actuator port that connects to the pump port side of the spool hole An orifice provided in the middle of the flow path between the pump port and the actuator port, a pressure chamber formed by the spool and the spool hole on the opposite side of the spool hole from the actuator port, and the pressure chamber downstream of the orifice. Side oil passage that guides pressure, a spring that is provided in the pressure chamber and that acts on the spool, a valve hole that is formed axially at the spool end facing the pressure chamber side, and a steel hole that is provided in this valve hole Sheet member and a steel poppet pressed against the sheet member, and the fluid pressure in the pressure chamber is equal to or higher than the set pressure. Since when, assuming the pressure control valve to which the structure to open the poppet escape portion of the fluid to the bypass port. Based on the above device, the present invention provides
At the end of the spool on the pressure chamber side, a tubular portion having a diameter smaller than that of the sliding portion of the spool is formed, and between the tubular portion and the sliding portion, a strain buffering portion having a thickness larger than that of the tubular portion is formed. And, after press-fitting the seat member having a caulking groove formed on the outer peripheral surface into the valve hole, caulking the tubular portion corresponding to the caulking groove,
The feature is that it is difficult to crimp the groove. .

[0009]

According to the present invention, the position of the seat member 18 can be determined by temporarily press-fitting the seat member 18 into the valve hole 17, and the deflection amount of the spring 13 of the relief valve, that is, the relief pressure can be easily set. Can be done. Then, the tubular portion 17c is caulked. That is, since the inner surface of the valve hole 17a is fixed in the caulking groove 19 and fixed, the seat member 16 can be securely fixed without being displaced at a high temperature, and the temperature expansion difference in the radial direction can be secured. Even if it occurs, since the relative position does not change in the axial direction, the set value of the relief pressure does not change. Further, when the sheet member 18 is crimped, distortion occurs in the both ends of the tubular portion 17c in the radial direction toward the outside with the crimped portion as the center. However, since the strain acts in the outward radial direction of the strain buffering portion, it does not affect the spool sliding portion.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the embodiment of the present invention shown in FIG.
While the spool 17 is made of aluminum as in the conventional case, the structure of the spool 17 is different from that of the conventional example.
Therefore, in the following, differences from the conventional example will be mainly described, and detailed description of common elements will be omitted. A valve hole 17a is formed in the spool 17 on the pressure chamber 5 side in the axial direction, and a cylindrical portion 17c having a smaller diameter than the sliding portion 17d is formed at the end of the spool 17. The valve hole 17a communicates with the bypass port B through the small through hole 17b as in the conventional case. Further, the tubular portion 1 is provided between the tubular portion 17c and the sliding portion 17d.
A strain buffering portion 17e having a thickness larger than that of 7c is formed.

Inside the valve hole 17a, the spring 13, the ball support 14, and the steel ball 15 are provided as in the conventional example.
To provide. Then, the iron seat member 18 is attached to the valve hole 17c.
Insert and fix to the end as described below. A caulking groove 19 is formed on the outer peripheral surface of the seat member 18, and the seat member 18 is first temporarily press-fitted into the valve hole 17a to seat the steel ball 15 on the seat portion 18a. Further, the press-fitting adjustment is performed until the position of the seat member 18 is determined, and the deflection amount of the spring 13, that is, the relief pressure is determined (see FIG. 2). Then, when the position of the sheet member 18 is determined, the caulking groove 1 formed in the sheet member 18
The cylindrical portion 17c corresponding to 9 is caulked from the outside, and the caulking groove 19 is not easily inserted and fixed. A filter 20 is fitted to the outermost end of the spool 17. More specifically, as shown in FIG. 2, the wall thickness of the most distal end of the cylindrical portion 17c is thinned to form a step portion 21, and the filter 20 is fitted into the step portion 21. And the cylinder part 1 with thin meat
7c By pushing the tip of the tip inward, the filter 2
0 is fixed.

In the pressure control valve described above, the caulking groove 19 is formed on the outer peripheral surface of the seat member 18, and
The seat member 18 is temporarily press-fitted into the valve hole 17a. Then, the tubular portion 17c is caulked, that is, a part of the tubular portion is inserted into the caulking groove 19 and fixed. Therefore, first, the sheet member 18 can be positioned and the relief pressure can be set by temporary press-fitting. Further, the caulking can cause the sheet member 16 to be displaced at a high temperature, or
It is prevented from coming off from the hole 3a.
That is, the amount of deflection of the spring 13 does not change, and the relief pressure does not change with temperature. Further, as in the conventional example, the sheet member 18 and the hole 17 are provided.
There is no need to screw into a. Here, when caulking the tubular portion 17c as in this embodiment, outward radial strain occurs at both ends of the tubular portion 17c around the crimped portion, but in the case of the present invention, Even if the strain acts on the thick strain absorbing portion in the radial direction, the strain is absorbed due to the thickness, so avoiding the influence of the strain on the sliding surface of the sliding portion 17d of the spool 17. You can

Although the caulking groove 19 is a single annular groove in this embodiment, the number thereof is not limited. Further, it is preferable to form the caulking groove 19 as an annular groove on the outer peripheral surface of the sheet member 18 in consideration of the sealing function, but if the sealing function is obtained by temporary press-fitting, it may be made partial if necessary. It doesn't matter. Further, in the first and second embodiments, the variable orifice on the connector 4 side may have any configuration. A fixed orifice may be used instead of the variable orifice. Furthermore, although the spherical steel ball 15 is used as the relief valve, an ordinary poppet type relief valve may be used. When using this poppet type relief valve, it is natural that the ball support 14 becomes unnecessary.

[0014]

According to the present invention, the weight of the device can be reduced by using aluminum, and the position of the sheet member does not deviate or fall out at high temperature. Therefore, it is not necessary to screw the sheet member to prevent it from coming off, the device assembly can be automated, and the sheet member can be manufactured by an inexpensive method such as sintering, and the cost can be reduced. Further, it becomes easy to adjust the relief pressure determined by the seat position. Furthermore, the strain generated during crimping does not affect the sliding surface of the sliding portion of the aluminum spool, and accurate control is possible.

[Brief description of drawings]

FIG. 1 is a sectional view of a pressure control valve of a first embodiment.

FIG. 2 is a sectional view of a main part of the device according to the first embodiment.

FIG. 3 is a sectional view of a conventional pressure control valve.

[Explanation of symbols]

 1 Body 5 Pressure Chamber 13 Spring 14 Ball Support 15 Steel Ball 16 Seat Member 17 Spool 17a Valve Hole 17c Cylindrical Part 17d Sliding Part 18 Seat Member 19 Caulking Groove

Claims (1)

[Claims] 1. An aluminum body in which a pump port and a bypass port are formed, a spool hole formed in the body, and a spool hole slidably incorporated in the body, and the pump port and the bypass port are communicated with each other according to the movement amount. Aluminum spool, an actuator port communicating with the pump port side of the spool hole, an orifice provided in the middle of the flow path between the pump port and the actuator port, on the opposite side of the spool hole from the actuator port,
A pressure chamber formed by the spool and the spool hole,
An oil passage that guides the pressure on the downstream side of the orifice to the pressure chamber, a spring that is provided in the pressure chamber and that acts on the spool, and a valve hole that is formed in the spool end facing the pressure chamber in the axial direction, A steel seat member provided in this valve hole and a steel poppet pressed against the seat member are provided, and when the fluid pressure in the pressure chamber exceeds a set pressure, the poppet is opened and a part of the fluid is opened. In the pressure control valve configured to allow the air to escape to the bypass port, the spool end portion on the pressure chamber side is formed with a tubular portion having a diameter smaller than the sliding portion of the spool, and between the tubular portion and the sliding portion. Is a strain buffering portion that is thicker than the tubular portion, and, after press-fitting a seat member having a caulking groove on the outer peripheral surface into the valve hole, caulking the tubular portion corresponding to the caulking groove, Make it difficult to crimp The pressure control valve according to claim.