JPS624779Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a fluid control valve, and more particularly to a negative pressure control valve that reduces sliding resistance of a piston while maintaining a sealing effect.

Conventionally, a fluid control valve has a piston that slides in the axial direction of the body through a guide in a body having an input port and an output port, and controls communication between the input port and the output port by the movement of the piston. , O-rings are disposed before and after a chamber connected to the input port and defined by the body and the piston, and the O-ring disposed on the piston is brought into contact with the bore of the body during reciprocating movement of the piston. Therefore, the piston is subjected to sliding resistance from both O-rings, and especially when hot water or the like is used as the fluid, the sliding resistance due to the O-rings becomes even greater due to expansion due to heat.

Therefore, the problem to be solved by this invention is to solve the conventional problems by reducing the sliding resistance of the piston during input/output port communication/blocking control. This idea is to solve the problem,
Basically, when the piston closes the input/output port, the O-ring placed on the piston contacts the conical surface formed in the bore of the body, and the piston moves in the opening direction so that the input/output port communicates with the O-ring placed on the piston. When moving, technical means are used to free the O-ring from the bore. Adopting this means can reduce the sliding resistance of the piston because the O-ring provided on the piston does not come into sliding contact with the inner wall surface of the bore.

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

The fluid control valve 1 has an input port 2 and an output port 3.
A cover 5 is fixed to an end of the body 4. Guide 6 inside body 4
It has a piston 7 guided by. piston 7
The inner peripheral part of the diaphragm 8 is fixed to the end of the diaphragm 8, and the outer peripheral part of the diaphragm 8 is held between the contact part between the body 4 and the cover 5. The diaphragm 8 creates a negative pressure chamber 9 defined by the cover 5 and the piston 7 and an atmospheric pressure chamber 10 defined by the body 4, the piston 7 and the guide 6. The atmospheric pressure chamber 10 is opened to the atmosphere through a passage 11 formed in the body 4, and the negative pressure chamber 9 is communicated with a negative pressure source through a negative pressure port 12. The piston 7 is normally biased to the left by the spring 13, as shown in FIG. 1, so that the valve portion 14 at the end of the piston 7 blocks communication between the input port 2 and the output port 3. . To ensure liquid tightness, seal rings 15 and 16 are placed at appropriate locations on the outer peripheral surface of the piston 7.

The guide 6 is formed from a metal material and has an annular protrusion 17 extending radially outward at one end. On the other hand, the body 4 is formed with a step 18 that comes into contact with the annular projection 17, and by bringing the projection 17 into contact with the step 18, the guide 6 is moved to the left as seen in FIG. to regulate the movement of A tapered surface 19 that becomes thicker as the outer end surface of the protrusion 17 goes toward its axial center.
Let it be. A C-ring 20 is used to hold the guide 6 in place. The ring 20 is composed of a bulging portion that enters at least two passages 11 bored in the body 4 and a remaining portion that is in contact with the tapered surface 19 of the protrusion 17 of the guide 6.
By engaging with the passage 11 bored in the ring and pressing the remaining part of the ring against the tapered surface 19 of the protrusion 17 of the guide 6, the guide 6 is forced to the left in FIG. 18 to hold the guide 6 in place (see FIG. 2).

The basic structure of this invention will be explained with reference to FIG. A seal groove 2 is provided at a distance on the outer peripheral surface of the piston 7.
1 and 22 are formed. An O-ring 15 is arranged in the seal groove 21 of the valve part 14, and a V-ring is arranged in the other seal groove 22.
A mold sealing material 16 is placed. Input port 2 of body 4
An annular conical surface 24 is formed in a portion of the bore 23 that is continuous with the piston 7 and in sliding contact with the piston 7. The sealing groove 21 of the valve portion 14 is connected to the O-ring 15 when the piston 7 is in the closed position shown in FIG. 1 or 3.
is provided in a position that makes surface contact with the annular conical surface 24 and prevents the fluid in the chamber 25 from flowing out to the output port 3 side. U-shaped seal material 16 in the other seal groove 22
contacts the guide 6 and prevents fluid from leaking into the atmospheric pressure chamber 10. Due to the pressure difference between the atmospheric pressure chamber 10 and the negative pressure chamber 9, the piston 7 moves as shown in FIG. 1 or 3.
When moving to the right, the O-ring 15 moves to the conical surface 2.
4 and the bore 23 of the body 4 to be in a free state, and only the U-shaped sealing material 16 comes into contact with the guide 6, making it possible to significantly reduce the sliding resistance of the piston 7. At this time, chamber 25 and output port 3
The sides communicate with each other, resulting in a fluid flow from the input port 2 to the output port 3. Furthermore, even when heated fluid is used, there is no increase in sliding resistance due to expansion of the O-ring 15, and smooth movement of the piston 7 can always be ensured.

As is clear from the above, in this invention, when the piston is in the closed position, the O-ring disposed on the piston makes surface contact with the annular conical surface formed on the body, thereby obtaining a sealing effect and closing the valve part. Since the O-ring is released from the bore of the body during operation of the piston, the sliding resistance of the piston is small and the piston can be operated smoothly. Even if hot water is used as the fluid, there is no effect of thermal expansion, so the movement of the piston is not inhibited, and there is little adverse effect on sliding resistance due to deformation of the piston or guide due to water absorption.In particular, the guide should be made of metal. Therefore, deformation of the guide due to water absorption can be avoided, and sliding resistance can be reduced and a sealing effect can be ensured.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an example of this invention, FIG. 2 is a partial sectional view showing an example of how the guide is attached, and FIG. 3 is a partial sectional view showing the arrangement of the sealing material. In the diagram: 1... Fluid control valve, 2, 3... Input/output port, 4... Body, 6... Guide, 7... Piston, 8... Diaphragm, 9... Negative pressure chamber, 10
... Atmospheric pressure chamber, 14 ... Valve part, 15 ... O-ring, 16 ... U-shaped sealing material, 20 ... Ring, 2
4... Annular conical surface.

Claims (1)

[Scope of utility model registration request] A fluid control valve in which a piston that is slid in the axial direction of the body through a guide is arranged in a body having an input port and an output port, and the communication between the input port and the output port is controlled by the movement of the piston. An annular conical surface is formed in a bore portion in the body that the outer circumferential surface of the piston slides on and that is continuous with the input port, and when the piston occupies a position that blocks communication between the input and output ports. , a fluid control valve configured to free an O-ring from the bore portion when the piston moves in an opening direction so that a seal disposed on the piston is brought into surface contact with the conical surface and the input/output port is communicated with the piston; .