JPS6358312B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a piston valve body which is slidably installed in a valve body having a through hole for inflow or outflow, and which is inserted into an annular groove formed on the outer circumferential surface of the piston valve body. The present invention relates to a switching valve in which an annular packing is arranged to seal the inner peripheral surface of the valve body, and the piston valve element slides across the inner opening of the through hole to switch the flow path.

Among these types of switching valves, a commonly used one is a spool valve in which the spool land portion serves as the piston valve body and the flow path can be switched by sliding the spool. However, the conventional spool valve uses a so-called O-ring made of a flexible elastic material as the annular packing, and uses the flexible elasticity of the O-ring to expand the ring and connect it to the land portion (piston valve body). ) is simply inserted from the outside into the annular groove formed on the outer circumferential surface of the O-ring, and the O-ring is brought into pressure contact with the inner circumferential surface of the valve body using its own elasticity and the pressure fluid pressure within the valve body. The seal is made by

However, such a seal structure has the advantage of being simple in structure and easy to install the O-ring, but on the other hand, since the O-ring is flexible, it is difficult to penetrate into the inner opening of the through hole. As the O-ring expands and deforms, a portion of the O-ring swells and once it passes through it, it contracts back to its original state, which causes energy loss due to the sliding of the spool, which not only reduces the switching efficiency of the valve, but also damages the O-ring itself. However, due to repeated expansion and contraction deformation, they quickly lose their elasticity, making it impossible to maintain a sealing effect for a long time, and they also have the drawback of being damaged by shear stress, which can lead to major accidents.

The present invention has been made to eliminate such drawbacks of the prior art, and its feature is that the annular packing is made of a hard material instead of a flexible material as in the conventional case, that is, the annular packing is made of a hard material facing the inner opening of the through hole and inserted therein. The valve body is made of a material that is strong enough not to deform even when subjected to bending stress in the direction of the pressure fluid pressure within the valve body. Also, if such a material is used, it will not be possible to use the flexible elasticity of the O-ring to expand the ring and install it. The annular gasket is constructed so that the annular gasket can be installed easily by making a cut and opening the mouth in the hole to attach the annular gasket. moreover,
When a split is made in the annular packing in this way, a problem arises in that the pressure fluid leaks there, but this can also be solved by using an elastic auxiliary packing prepared separately from the annular packing to open the above-mentioned split from the side. This is compensation for the blockage. Further, the split portion is designed so that it does not face the inner opening of the through hole.

Below, the present invention is applied to a spool valve.
An embodiment shown in FIG. 4 will be described in detail.

As shown in Fig. 1, this spool valve A is a cylindrical valve body a whose openings at both left and right ends are closed with covers 1 and 2, and a spool b is housed inside it so that it can slide left and right. In addition to being installed,
A solenoid valve C is attached to the outside of the cover 2.

This valve body a has two ports on the left and right through which pressure fluid flows in and out for sliding the spool b to the left or right.
through-holes 3, 3, and a plurality of (in this example, five) through-holes 4 for the inflow or outflow of pressure fluid that switches the flow path by sliding the spool b...
and are drilled. The through holes 3, 3 communicate with the electromagnetic valve C, and the operation of the electromagnetic valve C causes the spool b to reversely slide left and right. The pressure fluid is communicated with an inflow or outflow path 5 provided in the inflow or outflow path 5, through which pressure fluid flows in and out.

The number of spools b required is multiple (four in this example).
The piston valve body, that is, the land portion 6 is formed to protrude at a constant pitch on the left and right sides. An annular groove 7 having a rectangular cross section is formed on the outer peripheral surface of each land portion 6, and an annular packing 8 and an annular elastic auxiliary packing 9 are arranged in the following fitting relationship. .

That is, as shown in detail in FIGS. 2 and 3, the elastic auxiliary packing 9 has a gap 10 between it and the annular groove 7.
It has a concave cross section with a narrower width so as to form an annular recess ₉₁ on the outer peripheral surface, gap forming protrusions ₉₅ at multiple locations on the inner peripheral surface, and one outer surface. A small rotation-preventing convex portion ₉₂ is formed at a predetermined position. On the other hand, the cross-sectional shape of the annular packing 8 is simply rectangular, and the elastic auxiliary packing 9 is first placed in the annular groove 7, and the convex portion ₉₂ is fitted into a small recess ₇₁ formed on the inner surface of the annular groove 7. After that, the annular packing 8 is tightly fitted into the annular recess 9 ₁ of the elastic auxiliary packing 9, and both outer surfaces and inner circumferential surfaces of the annular packing 8 are brought into close contact with both inner surfaces and bottom surface of the annular recess 9 ₁ . The annular packing 8 is held by the elastic auxiliary packing 9, and in this state, the outer circumferential surface of the annular packing 8 is pressed against the inner circumferential surface of the valve body a due to the elasticity of the elastic auxiliary packing 9, and when not receiving pressure fluid pressure. However, a sealing action is now taking place.

Thus, while the elastic auxiliary packing 9 is made of a material with flexible elasticity, such as rubber, the annular packing 9 is made of a much harder material, such as a hard synthetic resin such as Diuracon. The bending stress in the direction facing the inner opening of the through hole 4 and entering there is applied by the pressure fluid pressure in the valve body a (which enters the gap 10 and acts on the annular packing 8 from the inside via the elastic auxiliary packing 9). It is strong enough to not deform even when subjected to stress.

Therefore, as shown in FIG. 2, even when both gaskets 8 and 9 face the inner opening of the through hole 4, the facing portions of both gaskets 8 and 9 deform outward (the annular gasket 8 deforms itself). Due to the strength, the annular packing 8 acts as a core and reinforces the elastic auxiliary packing 9)
There's nothing to do.

By the way, since the elastic auxiliary gasket 9 is made of a flexible elastic material, it can be easily fitted into the annular groove 7 with the ring expanded, but the annular gasket 8 is made of a hard material as described above. , it does not work in the same way as the elastic auxiliary gasket 9.

Therefore, as shown in detail in FIG. 4, the annular packing 8 is provided with splits ₈₁ at required positions on the circumference.
In order to fit the annular packing 8 into the annular recess 9 ₁ of the elastic auxiliary packing 9, the mouth of the split 8 ₁ is forcibly opened. The split 8 ₁ is formed stepwise in the width direction of the annular packing 8, and the left and right end portions 8 ₂ and 8 ₃ separated by the split 8 ₁ overlap in the width direction.

Further, when the annular packing 8 is provided with the split 8 ₁ in this way, _a problem arises in that the pressure fluid leaks from there to the left and right. Since they are tightly fitted, the left and right side walls 9 ₃ and 9 ₄ of the elastic auxiliary packing 9 are in close contact with the left and right sides, and this adhesion is further increased by pressure fluid pressure, so the split 8 ₁ is attached to both the left and right sides. It will be tightly closed and there will be no leakage.

Further, the annular packing 8 is positioned so that its split 8 ₁ is removed from the inner opening of the through hole 4 in the circumferential direction of the annular groove 7 and is tightly fitted into the annular recess 9 ₁ . 9 is the convex portion 9
₂ is fitted into the recess ₇₁ of the annular groove 7 to prevent rotation relative to the annular groove 7.
The split 8 ₁ moves integrally with the spool b without rotating relative to the annular groove 7 while the split 8 1 is removed from the inner opening of the through hole 4 as described above.
₁ does not face the inner opening of the through hole 4 and get caught on the rim thereof.

The annular packing 8 is tightly fitted into the annular recess ₉₁ as described above, so it hardly rotates in response to the annular recess 91. However, in order to reliably prevent this rotation, the third As shown in the figure, it is preferable to provide a recess 8 1 and a projection 9 ₆ for preventing rotation so that the annular packing 8 and the annular recess _{9 1} fit into each other.

In addition to the step-shaped split shown in Figure 4, the split 4 ₃ may also be a straight line parallel to the axis as shown in Figure 5, or an inclined one as shown in Figure 6. But that's fine.

As described above, the switching valve of the present invention includes an elastic auxiliary packing having a width that forms a gap between the annular groove of the piston valve body and a concave portion and a convex portion formed therein to prevent rotation. are fitted into each other, and an annular recess is formed on the outer circumferential surface of the elastic auxiliary packing, and a gap-forming convex portion is formed on the inner circumferential surface, and the annular packing is made of a material that is harder than the elastic auxiliary packing. The material is made of a material that is strong enough not to deform even when subjected to bending stress in the direction of facing the inner opening of the through hole and protruding into it due to the pressure fluid pressure inside the valve body, and the material is provided with cracks at required positions in the circumferential direction. , this annular packing is positioned so that its split is out of the inner opening of the through hole in the circumferential direction of the annular groove, and is tightly fitted into the annular recess of the elastic auxiliary packing. The annular packing is held by an elastic auxiliary packing with the side and inner circumferential surfaces brought into close contact with both inner surfaces and the bottom of the annular recess.

Therefore, according to the present invention, the annular packing that seals against the inner circumferential surface of the valve body is subjected to bending stress in the direction of facing the inner opening of the through hole and protruding therein by the pressure fluid pressure inside the valve body. The material is strong enough not to deform even when the valve body passes through the inner opening of the through-hole in the valve body, so unlike conventional O-rings, a portion of the O-ring swells into the through-hole each time the valve body passes through the inner opening of the through-hole. There is no repeated deformation such as bending or shrinking, and therefore not only can energy loss during sliding of the piston valve element be eliminated, but the life of the annular packing can be extended, and failures of the switching valve are less likely. .

Furthermore, even though the annular packing is made of a hard material as described above, it is easy to attach it to the piston valve body because it is made with a slot and the mouth is opened there.

Furthermore, even though the above-mentioned split is made, the annular packing is tightly fitted into the annular recess of the elastic auxiliary packing, and both outer surfaces and inner circumferential surfaces of the annular packing are fitted into both inner surfaces and bottom of the annular recess. The annular packing was held in close contact with the elastic auxiliary packing, and the split was closed from three sides with the elastic auxiliary packing.
Pressure fluid does not leak at this time, and the elastic auxiliary packing between the annular packing and the piston valve body
Since the cushioning action is performed in both directions in which the piston valve body slides and in the direction toward the center, even though the annular packing is made of a hard material, no unreasonable force is applied between the annular packing and the valve body and the piston valve body.

Furthermore, the annular packing is positioned so that its split is out of the inner opening of the through hole in the circumferential direction of the annular groove of the piston valve body, and the annular packing is tightly fitted into the annular recess of the elastic auxiliary packing. Rotation of the auxiliary packing with respect to the annular groove was prevented by fitting the concave and convex portions formed therein to prevent rotation, so that both of these packings were split so that the split was closer to the inner opening of the through hole as described above. It moves integrally with the piston valve body without rotating relative to the annular groove while remaining in the detached state, and the split does not face the inner opening of the through hole and get caught on its mouth edge.

In addition, since a gap is formed between the elastic auxiliary packing and the annular groove, the pressure fluid entering the gap can press the annular packing against the inner circumferential surface of the valve body, creating a seal. The effects are also good.

[Brief explanation of the drawing]

Figures 1 to 4 show an embodiment in which the present invention is applied to a spool valve, in which Figure 1 is an overall cross-sectional view, Figure 2 is an enlarged cross-sectional view, Figure 3 is an enlarged cross-sectional view of main parts, and Figure 3 is an enlarged cross-sectional view of the main part. FIG. 4 is an enlarged plan view showing the structure of the split part of the annular packing, and FIGS. 5 and 6 are plan views showing other examples of the split part. 6... Land portion that functions as a piston valve body,
4... Through hole, a... Valve body, 7... Annular groove, 8
...Annular packing, 9...Elastic auxiliary packing, 7
₁ , 9 ₂ ... Concavities and protrusions for preventing rotation, 9 ₁ ...
Annular recess, 9 ₅ ... gap forming protrusion, 8 ₁ ... split.

Claims (1)

[Claims] 1. A piston valve body is slidably installed in a valve body having a through hole for inflow or outflow, and a seal is provided on the inner circumference of the valve body in an annular groove formed on the outer circumference of the piston valve body. In the switching valve, an annular gasket is disposed, and the piston valve element slides across the inner opening of the through hole to switch the flow path, and the annular gasket is disposed within the annular groove and between the piston valve body and the through hole. An elastic auxiliary packing having a width that forms a gap is arranged, and a concave portion and a convex portion formed thereon for preventing rotation are fitted into each other, and an annular recess is formed on the outer peripheral surface of the elastic auxiliary packing, and an annular recess is formed on the inner circumferential surface of the elastic auxiliary packing. A gap-forming convex portion is formed on the circumferential surface, and the annular packing is harder than the elastic auxiliary packing, and the bending stress in the direction of facing the inner opening of the through hole and protruding therein is applied to the annular packing. The material is made of a material that has a strength that does not deform even when subjected to pressure fluid pressure, and is provided with cracks at required positions in the circumferential direction. The elastic auxiliary packing is positioned so that it comes off, and is tightly fitted into the annular recess of the elastic auxiliary packing, and the elastic auxiliary packing is fitted tightly into the annular recess, and the elastic auxiliary packing is fitted tightly into the annular recess. A switching valve characterized by holding a seal.