JPH0220539Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a spool valve used in industrial machinery that utilizes fluid pressure.

[Prior Art] Conventionally, as shown in FIG. 5, a valve housing 1 is provided with a valve stem 2 slidably inserted in the axial direction inside the valve housing 1, and an input port 7 and an output port are provided on the inner wall of the valve housing 1. A valve seat 4 is provided between the valve stem 2 and the outer circumferential groove 5 of the valve stem 2.
The length of the annular elastic valve body 6 in the radial direction is larger than the thickness in the axial direction, and the valve body 6 is slid onto the valve seat 4 from the output port 8 side in the valve housing 1. A spool valve in which both ports are brought into contact with each other to open and close the two ports is known (see, for example, Japanese Patent Publication No. 48-4647).

Since the valve body 6 has an elongated cross section in the radial direction, it is easily bent by sliding of the valve stem 2 and seals the valve seat 4. In order to prevent tilting due to fluid pressure etc. when sliding from the 8 side to the input port 7 side where fluid pressure is high and riding on the valve seat 4, a support wall 3 integrated with the valve stem 2 is provided behind it. Therefore, due to the sliding resistance caused by the contact with the valve seat 4 when the valve stem 2 slides and the fluid pressure acting on the valve body 6, the tip of the valve body 6 is moved between the valve seat 4 and the support wall 3. It may get caught in the

This pinching of the valve body 6 increases the sliding resistance of the valve stem 2, which not only requires a large operating force, but also if the pinching is significant, the valve stem 2
There is a disadvantage that the valve body 6 becomes unable to slide or the valve body 6 is worn out.

[Problem to be solved by the invention] The problem to be solved by the invention is to prevent the valve body from being pinched between the valve seat and the valve stem by giving directionality to the bending of the valve body. points.

[Means for Solving the Problems] The present invention, in the above-mentioned known spool valve, forms a tapered surface at the end of the output port side of the valve seat on the inner wall of the valve casing, and forms a tapered surface on the end of the valve seat on the output port side facing the input port on the elastic valve body. A concave portion is provided on the fluid pressure acting surface side to bend it into a dogleg shape, and the tip side of the valve body is bent toward the input port side within the outer circumferential groove of the valve stem, so that the tapered surface is bent. The angle θ ₁ formed with the axis, the angle θ ₂ at which the bent portion of the valve body is inclined with respect to the plane perpendicular to the axis, and the angle θ ₃ formed between the sealing surface at the tip of the bent portion and the tapered surface, are expressed as θ< The above problems are solved by setting θ ₁ ≦θ ₂ ≦45° and θ ₃ ≧0°.

[Operation] When the valve stem is slid from the output port side toward the valve seat, the sealing surface at the tip of the valve body comes into contact with the tapered surface of the valve seat and is pressed.

In this case, the bent portion on the tip side of the valve body is inclined toward the valve seat, and the angle θ ₃ between the sealing surface of the bent portion and the tapered surface is equal to or larger than the angle θ ₁ of the tapered surface. Therefore, a force acts on the bent portion of the valve body to incline it toward the input port, and this force prevents the tip portion of the valve body from being pinched as described above. Bending of the bent portion toward the input port side due to the above force is easy because the length in the radial direction of the valve body is made larger than the thickness in the axial direction so that the valve body can be easily bent.

As the valve stem continues to slide, the sealing surface of the valve body comes into pressure contact with the valve seat, but since the valve body tends to tilt toward the input port due to the above bending, there is a gap between the valve seat and the supporting wall of the valve stem. Never get caught.

When the sealing surface comes into pressure contact with the valve seat, the bent portion receives a force in an upright direction due to the fluid pressure acting on the fluid pressure acting surface facing the input port, thereby reliably sealing the valve seat. Therefore, as the fluid pressure increases, the sealing force of the valve body also increases.

[Embodiment] Figures 1 and 2 show a first embodiment of the present invention, in which a valve stem 12 is inserted into a valve housing 11 of a spool valve so as to be slidable in the axial direction. 12 is
It is configured to be driven by electromagnetic operating force, mechanical operating force, or fluid pressure operating force acting on the end portion.

The valve housing 11 includes an input port 13 in the center of the valve housing,
Output ports 14a, 14b on both sides thereof, discharge ports 15a, 15b on both sides thereof, and inner circumferential grooves 16 communicating with these ports, and valve seats 17a, 17b,... on the inner wall of the valve casing between these inner circumferential grooves. 18
a, 18b, and an angle θ ₁ is formed at the end of each valve seat on the contact side of the valve body described later with respect to the cylindrical surface of the inner wall of the valve housing.
A tapered surface 19 is provided.

The valve stem 12 includes annular elastic valve bodies 20a, 21a that abut against the valve seats 17a, 18a, and the valve seat 1.
an annular elastic valve body 20b that abuts on 7b and 18b;
21b are fitted around the outer circumferential grooves 22, . . . .

In the drawings, the valve bodies 20a, 20b, 2
1a and 21b are all shown as having the same shape, but the problem here is that the input port 1
3 and the output ports 14a, 14b.
A valve body 20 that approaches and separates from the output port side on a and 17b
a, 20b, that is, the valve bodies that slide from the output port side where the fluid pressure is low to the input port side where the fluid pressure is high and ride on the valve seat.Therefore, the other valve bodies have the structure described below. Any suitable structure can be adopted without limitation.

The above-mentioned valve bodies, particularly the valve bodies 20a and 20b, contact the valve seat on the inner wall of the valve housing to open and close the flow path between the ports opened on the inner wall of the valve housing, and are made of an elastic material.
As shown in FIG. 2, the length b in the radial direction of the spool is larger than the thickness a in the axial direction of the spool, and the thickness a is formed smaller than the width of the outer circumferential groove 22, so that the length b in the radial direction of the spool is larger than the thickness a in the axial direction. A gap 23 is provided between the groove and the groove to allow fluid to enter and exit.

Further, the valve body is provided with a recess 24 for bending the valve body itself in a dogleg shape on the fluid pressure acting surface side facing the input port, and the tip side of the valve body is placed in the outer circumferential groove 22 of the valve stem. A sealing surface 26 is formed at the distal end of the bent portion 25 on the distal end side, which is bent toward the input port side and seals by contacting the valve seat.

The bent portion 25 is inclined toward the input port 13 by an angle θ ₂ with respect to a plane perpendicular to the axis of the valve stem 2, and the angle θ ₂ is made equal to or larger than the angle θ ₁ . , sealing surface 26 and tapered surface 19
By making the angle θ ₃ equal to or larger than the above-mentioned angle θ ₁ , that is, θ<θ ₁ ≦θ ₂ ≦45° θ ₃ ≧0°, the sealing surface 26 becomes the tapered surface 1.
The bent portion 25 is formed so as to be bent toward the input port 13 when it comes into contact with the input port 9 . In addition, the radial length b of the bent portion 25 is defined as the axial thickness a.
By making the diameter larger than that, the above-mentioned bending is promoted.

In FIG. 2, the back surface of the bent portion 25 is inclined at an angle α with respect to the inner surface of the support wall forming the outer circumferential groove 22, but this angle may be 0°.

Next, the operation of the first embodiment will be explained.

The upper half of FIG. 1 shows the state in which the valve stem 2 is sliding;
The lower half shows the state in which sliding has been completed.

Before the valve stem 12 slides, the valve stem is located at the left end in the valve housing, and the valve bodies 20b, 21a are located at the valve seats 17b, 1.
8a is closed, and the valve bodies 20a and 21b are closed to the valve seat 17.
This is the state where a and 18b are open. In this state, when the valve stem 12 slides to the right in the figure with an appropriate operating force, the valve body 12 moves as shown in the upper half of FIG.
The sealing surfaces 26 of 0a and 21b are the valve seats 17a and 18
It is pressed against the tapered surface 19 of b.

In this case, the angle θ ₃ is equal to or greater than the angle θ ₁ , and the angle θ ₂ is equal to or greater than the angle θ ₁ , so that the valve body is in contact with the tapered surface 19. Since the valve body is subjected to a tilting force toward the mounting part, the radial length b of the valve body is reduced to the axial thickness a.
Coupled with the fact that the valve body is made larger than the above, the bent portion 25 of the valve body is bent toward the fluid pressure acting surface side. In this case, since the gap 23 is formed between the fluid pressure acting surface of the valve body and the outer circumferential groove 22, the valve body can be easily bent.

Therefore, a part of the valve body is not caught between the valve seat 17a and the valve stem.

When the valve stem 12 further slides to the right, the valve body 2
The bent portion 25 of 0a, 21b is the sealing surface 2
6 comes into contact with the valve seats 17a, 18b and seals them.
In this case, the bent portions 25 of the valve bodies 20a, 21b
is subjected to an upward force due to the fluid pressure, so the sealing of the valve seat by the sealing surface 26 is reliable, and the sealing force becomes stronger as the fluid pressure increases.

When the valve stem 12 slides to the left in the figure in this state, the flow path switches and returns to the original state, but the actions of the valve bodies 20b and 21a in this case are the same as in the above case, so please refer to the following for details. Further explanation will be omitted.

Note that the spool valve of the present invention may be one that opens and closes a fluid flow path, and is of course not limited to the above-mentioned 5-port valve.

FIG. 3 shows a second embodiment of the present invention, in which a valve body 30
The sealing surface 32 is flat and has an angle θ ₃ greater than 0°.

FIG. 4 shows a third embodiment of the present invention, in which the valve body 35
is further bent in the opposite direction by the second recess 37 formed in the inner portion 36 and the knee portion 38 to form a zigzag shape. The valve body 35 in this embodiment can be bent more easily by the second recess 37 and the knee portion 38.

Other structures and functions of the second and third embodiments are as follows.
Since this is the same as the embodiment, the same or corresponding parts are denoted by the same reference numerals in the drawings, and detailed description thereof will be omitted.

[Effects of the invention] The present invention prevents the valve body from being caught between the valve seat and the valve stem by bending toward the fluid pressure acting surface when the valve stem slides. Increase in dynamic resistance and wear and tear on the valve body can be prevented.

Further, after opening and closing the flow path, the valve body receives a force to return to its original state due to the fluid pressure acting on the fluid pressure acting surface, so that the seal is reliable.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional front view of the first embodiment of the present invention.
The upper half shows the state in which the valve stem is sliding, and the lower half shows the state in which the valve stem has finished sliding. Figure 2 is an enlarged cross-sectional view of the main parts of the same, and Figures 3 and 4 are views of the present invention. FIG. 5 is an enlarged sectional view of the main part of another embodiment, and FIG. 5 is an enlarged sectional view of the main part of the conventional example. 11... Valve housing, 12... Valve stem, 17a, 17
b, 18a, 18b...valve seat, 19...tapered surface, 20a, 20b, 21a, 21b, 30, 3
5...Elastic valve body, 22...Outer circumferential groove, 26, 31...
...Seal surface.

Claims (1)

[Scope of Claim for Utility Model Registration] A valve seat consisting of a valve housing and a valve stem slidably inserted in the axial direction inside the valve housing, and located between an input port and an output port on the inner wall of the valve housing. an annular elastic valve body fitted in the outer circumferential groove of the valve stem, the length in the radial direction being larger than the thickness in the axial direction, and this valve body being output to the valve seat within the valve housing. In a spool valve that opens and closes between both ports by sliding contact from the port side, a tapered surface is formed at the end of the valve seat on the output port side on the inner wall of the valve housing, and the elastic valve body A concave portion is provided on the fluid pressure acting surface side facing the input port in the valve body, and the distal end side of the valve body is bent toward the input port side within the outer circumferential groove of the valve stem. , the angle θ ₁ that the tapered surface makes with the axis, the angle θ ₂ that the bent portion of the valve body inclines with respect to the plane perpendicular to the axis, and the angle θ between the sealing surface at the tip of the bent portion and the tapered surface. _3. A spool valve characterized in that θ<θ ₁ ≦θ ₂ ≦45° and θ ₃ ≧0°.