JP4996990B2 - Relief valve - Google Patents

Description

  The present invention relates to a relief valve that opens when the primary fluid pressure reaches a preset pressure (hereinafter referred to as set pressure) and closes when the primary fluid pressure drops below the set pressure. It is.

  Conventionally, as described in Japanese Patent Application Laid-Open No. 2000-154881, a valve body is disposed in a valve chamber in a valve housing, and a valve seat is defined by a valve seat portion to which the valve body contacts and separates. There is a relief valve configured such that the port is a primary pressure port, a secondary pressure port is provided on the valve chamber side, and the valve body is opened away from the valve seat when the primary pressure reaches a predetermined value. This relief valve is characterized in that it is configured to be surely opened without being affected by the secondary pressure by making the seal passage of the valve shaft portion by the annular seal member and the aperture of the valve port the same. To do.

Japanese Patent Laid-Open No. 7-330087 discloses a relief valve for controlling excessive supply of liquid in a system for quantitatively supplying liquid. This relief valve uses the pressure of compressed air in order to adjust the force pressing the valve stem against the valve seat packing and the O-ring with a pressure width smaller than 0.1 kg / cm ² . This makes it possible to finely set the pressure (set pressure) when the relief valve opens.
JP 2000-154881 A JP-A-7-330087

  As disclosed in these patent documents, various proposals have conventionally been made for the relief valve and the relief valve. However, when the conventional relief valve is opened and closed multiple times, the relief valve The valve opening pressure, that is, the valve opening pressure may gradually change. If the opening pressure of the relief valve gradually changes while the relief valve is continuously used, the pressure of the system to which the relief valve is attached cannot be maintained at a predetermined pressure for a long period of time.

  In addition, in order to maintain the pressure of the system with the relief valve more accurately at the set pressure, when the system pressure rises above the set pressure, the system pressure is reduced to the predetermined pressure as quickly as possible. There is a need. In order to reduce the system pressure in a short time, the time required from when the system pressure reaches the relief valve opening pressure until the relief valve is completely opened (hereinafter referred to as valve opening time). It is effective to shorten as much as possible.

  An object of the present invention is to provide a relief valve that prevents the valve opening pressure from changing each time even when the valve is opened and closed a plurality of times.

  Another object of the present invention is to provide a relief valve that is fully opened in a short time when the fluid pressure in the primary port reaches a preset pressure (set pressure).

  Still another object of the present invention is to provide a relief valve that can maintain the pressure of a system equipped with a relief valve at a predetermined pressure over a long period of time.

  Still another object of the present invention is to provide a relief valve that is simple in construction, can be miniaturized, and is easy to manufacture.

In the relief valve of the present invention, a primary port and a secondary port are formed in the valve box of the relief valve, and a member having a cylinder part and a member having a piston part are attached to the valve box, The piston portion is disposed between an opening on the downstream side of the primary port and an opening on the upstream side of the secondary port, and the piston portion reciprocates toward the opening on the downstream side of the primary port. The piston portion is slidably engaged with the cylinder portion, and the piston portion is connected to the primary port so that the piston portion blocks the primary port and the secondary port. When spring means that constantly urges toward the opening on the downstream side is provided, and the piston part moves by a predetermined distance in the direction against the elastic force of the spring means under the fluid pressure of the primary side port , The primary port becomes the secondary port In the relief valve configured to pass, an annular groove that surrounds the opening on the upstream side of the primary port and opens toward the cylinder is formed in the valve box, An annular seal member made of an elastic material is fitted into the annular groove, the annular seal member is protruded toward the cylinder portion from the downstream side opening of the primary port, and the bottom portion of the cylinder portion is A through-hole is formed in the bottom of the cylinder portion so as to be crimped to the annular seal member, opening toward the opening on the downstream side of the primary port and exposing the inner peripheral edge of the annular seal member. A projecting portion protruding into and out of the through hole is formed on an end surface of the piston portion on the primary port side, the projecting portion enters the through hole, and the piston portion is elastically deformed by the spring means. The cylinder part by force When closely contacting the bottom portion, the position of the piston portion is regulated by the cylinder portion, the projecting portion is crimped to the inner peripheral edge portion of the annular seal member, and the projecting portion and the annular seal member are disposed on the inner side of the intimate portion. It is characterized in that a pressure receiving surface for fluid pressure of the primary side port is defined.

In the relief valve of the present invention, a through-hole that opens toward an opening on the upstream side of the secondary port is formed in the side wall portion of the cylinder portion, and the piston portion is a fluid of the primary port. When the pressure is received and moved by a predetermined distance in a direction against the elastic force of the spring means, the through hole in the side wall of the cylinder portion opens, and the fluid pressure in the primary port is changed to the secondary side. It is characterized by being opened to a port.

In the relief valve of the present invention, the piston portion further extends to an outer surface of the projecting portion on an end surface of the piston portion on the primary port side, and the piston portion is the annular seal. It has a 2nd pressure receiving surface which receives the fluid pressure of the primary side port when it separates from a member.
The relief valve of the present invention further separates the piston portion from the annular seal member when the fluid pressure at the primary port increases and the adhesion force between the piston portion and the annular seal member decreases. Before the operation, a part of the fluid pressure of the primary port acts on the second pressure receiving surface.

  In the relief valve of the present invention, when the valve element is seated on the valve seat member, the area of the pressure receiving surface on which the fluid pressure of the primary port acts is always constant, so the relief valve is opened and closed several times. However, the valve opening pressure does not change each time. Therefore, according to the relief valve of the present invention, the pressure of the system equipped with the relief valve can be maintained at a predetermined pressure over a long period of time.

  The relief valve of the present invention is located on the downstream side of the first pressure receiving surface, in addition to the first pressure receiving surface on which the fluid pressure of the primary port acts when the valve body is seated on the valve seat member. When the valve body is separated from the valve seat member, the fluid pressure of the primary side port acts, and when the valve body is separated from the valve seat member, the fluid pressure of the primary side port is the first pressure pressure. In addition to the pressure receiving surface, it also acts on the second pressure receiving surface. For this reason, the force for displacing the valve body in the valve opening direction is increased by the increase in the area of the pressure receiving surface, so that the valve body can be displaced to the fully open position all at once in a short time.

  The relief valve of the present invention also reduces the sealing force between the valve body and the valve seat member due to an increase in the fluid pressure of the primary side port, and the valve body is still completely separated from the valve seat member. When not in the state, by applying a part of the fluid pressure of the primary side port to the second pressure receiving surface, from the center of the first pressure receiving surface to the secondary side port through the second pressure receiving surface A decreasing pressure gradient can be formed. That is, when the set pressure P1 of the relief valve is acting on the first pressure receiving surface, if the pressure acting on the second pressure receiving surface is P2, generally P2 <P1. The reason why P2 is smaller than P1 is that a part of the fluid acting on the second pressure receiving surface leaks outside from the secondary port along the outer surface of the valve body. By forming such a pressure gradient, the fluid can be smoothly moved from the primary port to the secondary port when the valve is opened.

The relief valve of the present invention can further reduce the area of the first pressure receiving surface without reducing the total area of the first pressure receiving surface and the second pressure receiving surface. If the area of the first pressure receiving surface is reduced, the sealing degree between the valve body and the valve seat member can be improved, and at the same time, the urging force such as a compression coil spring that urges the valve body toward the valve seat member is reduced. Can be made. For this reason, a compression coil spring etc. can be reduced in size and a relief valve can be reduced in size.
Other features of the present invention will become apparent from the following description of embodiments, described with reference to the drawings.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The illustrated relief valve 1 is a pressure relief valve for releasing the pressure into the atmosphere when the compressed air in the system reaches a preset pressure.

  As shown in FIG. 1, the relief valve 1 includes a valve box 2, an adapter member 3 screwed to the valve box 2, a set pressure adjusting member 4 screwed to the adapter member 3, and an adapter member 3. The valve rod 5 slidably supported by the pressure adjusting member 4, the compression coil spring 6 interposed between the set pressure adjusting member 4 and the valve rod 5, and the outer surface of the set pressure adjusting member 4 are screwed together. The lock nut 7 prevents the relative displacement between the adapter member 3 and the set pressure adjusting member 4. These components can be formed of a suitable metal or metal alloy.

  The valve box 2 includes a primary side port 8, a secondary side port 9, and an adapter member mounting hole 10. The primary port 8 extends in the vertical direction in the drawing along the central axis of the valve box 2, and has an opening 11 on the bottom surface of the adapter member mounting hole 10. The secondary side port 9 extends in the radial direction around the central axis CA of the valve box 2 and allows the adapter member mounting hole 10 to communicate with the outside of the valve box 2. The valve box 2 can be provided with a plurality of secondary ports 9. As shown in FIGS. 2 and 3, an annular groove 12 that opens to the bottom surface of the adapter member mounting hole 10 is formed on the bottom surface of the adapter member mounting hole 10. The annular groove 12 extends annularly along the bottom surface of the adapter member mounting hole 10 and surrounds the opening 11 of the primary side port 8. An annular seal member 13 made of an elastic material such as a rubber material is attached to the annular groove 12. The annular seal member 13 projects upward from the opening 11 of the primary port 8 in a state of being fitted into the annular groove 12.

  The adapter member 3 is composed of a tubular hollow body as a whole, and includes a small-diameter cylinder portion 14 to which the valve stem 5 is slidably guided, and a large-diameter tubular support portion 15 to which the set pressure adjusting member 4 is connected. Have. A through hole 17 is formed at the center of the bottom portion 16 of the cylinder portion 14, and the through hole 17 opens toward the opening portion 11 of the primary side port 8. A through hole 19 is formed in the side wall portion 18 of the cylinder portion 14, and the through hole 19 opens toward the corresponding secondary port 9. A male screw portion 20 is formed on the outer peripheral surface of the large-diameter tubular support portion 15, and a female screw portion 21 is formed on the inner peripheral surface thereof. A female screw portion 22 is formed on the inner peripheral surface of the adapter member mounting hole 10 of the valve box 2, and the adapter member 3 is formed by replacing the male screw portion 20 formed on the outer peripheral surface of the adapter member 3 with the female screw portion of the valve box 2. 22 and screwed into the adapter member mounting hole 10. At this time, the annular wall 23 extending around the through hole 17 of the cylinder portion 14 contacts a part of the upper surface of the annular seal member 13, and fixes the annular seal member 13 inside the annular groove 12. The side wall portion 18 and the annular wall 23 of the cylinder portion 14 constitute a position restricting member that restricts the seating position of the valve stem 5. An annular passage 24 is defined between the side wall portion 18 of the cylinder portion 14 and the valve box 2, and the through hole 19 communicates with the secondary port 9 through the annular passage 24.

  A large-diameter piston portion 25 is formed at the lower end of the valve stem 5, and a cylindrical protrusion 26 is formed at the center of the lower end surface of the piston portion 25. As clearly shown in FIG. 4, the end surface S1 of the cylindrical protrusion 26 is a pressure receiving surface on which the fluid pressure of the primary port 8 acts when the valve is closed, that is, the first pressure receiving surface. An end surface S2 of the piston portion 25 that extends annularly around the pressure receiving surface is a pressure receiving surface that is newly exposed to the primary port 8 when the valve is opened, that is, a second pressure receiving surface.

The piston portion 25 is slidably fitted into the cylinder portion 14 of the adapter member 3, and the cylindrical projection portion 26 can enter the through hole 17 formed in the bottom portion 16 of the cylinder portion 14. A small-diameter guide portion 27 is formed at the upper end portion of the valve stem 5, and the guide portion 27 is slidably inserted into a through hole 28 formed in the set pressure adjusting member 4. A male screw portion 29 is formed on the outer peripheral surface of the set pressure adjusting member 4, and the set pressure adjusting member 4 is attached to the adapter member 3 by screwing the male screw portion 29 with the female screw portion 21 of the adapter member 3. Is done. A compression coil spring 6 is interposed between the piston portion 25 of the valve stem 5 and the set pressure adjusting member 4, and the compression coil spring 6 constantly urges the valve stem 5 downwardly. The elastic force by which the compression coil spring 6 urges the valve stem 5 can be adjusted by rotating the set pressure adjusting member 4 with respect to the adapter member 3. The lock nut 7 is screwed into the male thread portion 29 of the set pressure adjusting member 4, and the set pressure adjusting member 4 can be fixed to the adapter member 3 by tightening the lock nut 7 to the adapter member 3. Thereby, it can prevent that the urging | biasing force of the compression coil spring 6 changes.

  Hereinafter, the operation of this embodiment will be described. In the description of the present embodiment, the relief valve 1 is attached to the outer wall of a pressure chamber (not shown) into which compressed air flows by a male screw portion 30 formed at the lower portion of the outer peripheral surface of the valve box 2. The secondary port 8 communicates with the pressure chamber, and the secondary port 9 is open to the atmosphere.

  1 to 3 show a non-pressurized state in which no fluid pressure acts on the primary port 8. In this non-pressurized state, the valve stem 5 is positioned at the lowermost end by the elastic force of the compression coil spring 6, and the piston portion 25 is in contact with the bottom portion 16 of the cylinder portion 14. At this time, the cylindrical protrusion 26 of the valve stem 5 passes through the through hole 17 of the bottom portion 16 and abuts against the annular seal member 13 to block the primary side port 8 from the secondary side port 9. As shown in FIG. 3, the cylindrical protrusion 26 and the annular seal member 13 are configured so that the peripheral port 26 a of the cylindrical protrusion 26 is crimped to the inner peripheral edge 13 a of the annular seal member 13. Seal. Since the peripheral edge 26a of the cylindrical protrusion 26 has a smoothly convexly curved surface, the annular seal member 13 has a smoothly concavely curved surface between the peripheral edge 26a of the cylindrical protrusion 26. A belt-like sealing surface is formed. The belt-like seal surface extends in an annular shape along the inner peripheral edge portion 13 a of the annular seal member 13.

  In the state shown in FIGS. 1 to 3, when compressed air flows into the primary port 8, the compressed air pressure acts on the first pressure receiving surface S <b> 1 of the valve stem 5. The first pressure-receiving surface S1 is a pressure-receiving surface that is formed on the end surface of the cylindrical protrusion 26 and on which the fluid pressure of the primary port 8 acts when the valve is closed. Accordingly, when the valve is closed as shown in FIGS. 1 to 3, the first pressure receiving surface S <b> 1 is formed inside the annular contact portion between the annular seal member 13 and the end surface of the cylindrical protrusion 26.

  When the pressure of the compressed air flowing into the primary port 8 of the relief valve 1 rises and reaches a pressure (set pressure) set in advance as the pressure at which the relief valve 1 should be opened, the valve stem 5 is compressed coil spring. The cylindrical protrusion 26 of the valve stem 5 is separated from the annular seal member 13. As a result, in addition to the first pressure receiving surface S1 of the valve stem 5, the compressed air pressure of the primary port 8 also acts on the second pressure receiving surface S2, so that the valve rod 5 is connected to the first pressure receiving surface S1 and the second pressure receiving surface. Due to the compressed air pressure applied to the sum total of the surface S2, it rises all at once, and the valve opening state shown in FIGS. The second pressure receiving surface S <b> 2 is an end surface of the piston portion 25 that extends annularly around the cylindrical projection portion 26 of the valve stem 5, and the cylindrical projection portion 26 of the valve stem 5 is in close contact with the annular seal member 13. When the valve is closed, it does not receive the compressed air pressure of the primary port 8, but when the valve is opened, it is newly exposed to the primary port 8, and the pressure receiving surface on which the compressed air pressure of the primary port 8 is imprinted. is there. The area of the first pressure receiving surface S1 when the valve is opened shown in FIGS. 4 to 6 is larger than the area of the first pressure receiving surface S1 when the valve is closed shown in FIGS. And the area of the close contact portion of the annular seal member 13 is increased. Therefore, when the cylindrical protrusion 26 of the valve stem 5 is separated from the annular seal member 13, the area of the compressed air pressure acting on the valve stem 5 is strictly equal to the increase of the first pressure receiving surface S1 and the second pressure. This is the total area of the pressure receiving surface S2.

  The set pressure of the relief valve 1 can be set to an arbitrary value by loosening the lock nut 7, rotating the set pressure adjusting member 4 with respect to the adapter member 3, and adjusting the resilience of the compression coil spring 6. .

  When the compressed air pressure at the primary side port 8 of the relief valve 1 reaches the set pressure and the valve stem 5 rises to the upper end position shown in FIGS. 4 to 6 in a very short time, the compressed air at the primary side port 8 becomes as shown in FIG. As shown by an arrow F, the secondary port 9 passes through the opening 11, the through-hole 17, the communication chamber 31 formed between the adapter member 3 and the piston 25, the through-hole 19, and the annular passage 24. Released into. As a result, the compressed air pressure of the primary port 8 drops below the set pressure of the relief valve 1, and the valve stem 5 is lowered to the lowermost position by the elastic force of the compression coil spring 6, and the state shown in FIGS. Return to. Thereafter, the valve stem 5 moves up and down to repeat the above operation.

  1 to 3, the space between the cylindrical protrusion 26 of the valve stem 5 and the annular seal member 13 is completely sealed, and the side surface of the cylindrical protrusion 26 and the through hole 17 of the adapter member 3 are There are gaps between the second pressure receiving surface S2 and the bottom portion 16 of the cylinder portion 14 of the adapter member 3, and between the side surface of the biston portion 25 and the inner wall surface of the cylinder portion 14 of the adapter member 3. It is an explanation in a state where it is not. However, in practice, a gap is required between the side surface of the cylindrical protrusion 26 and the through hole 17 of the adapter member 3 so that these members are relatively displaced, and the relief valve 1 is shown in FIG. In some cases, the seal between the cylindrical protrusion 26 and the annular seal member 13 is partially released during the period from the closed state 1 to 3 to the open state shown in FIGS. An example of such a state is shown in FIGS. 7, 8 and 9B.

  7, 8, and 9 (B), compression air pressure acts on the primary side port 8 of the relief valve 1 in the state of FIGS. 1 to 3, and the valve stem 5 resists the elastic force of the compression coil spring 6. The state where only a small amount a is raised is shown. FIG. 9A shows the state of FIG. 3 in which the valve stem 5 is at the lowermost position, and FIG. 9B shows the reason why the valve stem 5 is shown in FIG. This is for the purpose of clarifying a state in which the valve has been lifted by a small amount a from the closed position. Now, as shown in FIG. 9B, in the state where the valve stem 5 is lifted by a minute amount a, the contact between the cylindrical protrusion 26 of the valve stem 5 and the annular seal member 13 is completely released. The compressed air in the primary port 8 passes between the cylindrical protrusion 26 and the annular seal member 13 and flows into the through hole 17, and then below the bottom surface 16 of the cylinder portion 14 and the piston portion 25. Passing through the gap b between the end faces and the gap c between the inner wall surface of the side wall 18 of the cylinder part 14 and the peripheral surface of the piston part 25, the gas flows out of the through hole 19 into the annular passage 24 and flows into the secondary side port 9. Through the atmosphere. Since these gaps b and c are very small, the flow rate of compressed air discharged from the secondary port 9 is small, but the gap c communicates with the secondary port 9 opened to atmospheric pressure. The compressed air flow flowing from the primary port 8 toward the secondary port 9 is considered to have a pressure gradient that decreases from the primary port 8 toward the secondary port 9. Accordingly, it can be considered that the compressed air pressure in the gap b is a pressure value between the compressed air pressure of the primary side port 8 and the atmospheric pressure of the secondary side port 9. 7, 8, and 9 (B), assuming that the compressed air pressure in the gap b is about ½ of the compressed air pressure P of the primary port 8, the valve opening force acting on the valve stem 5 is It is considered to be the sum of a value obtained by multiplying the first pressure receiving surface S1 by the compressed air pressure P and a value obtained by multiplying the second pressure receiving surface S2 by the compressed air pressure P / 2. That is, the relief valve 1 undergoes the transition states shown in FIGS. 7, 8 and 9 (B) while changing from the closed state shown in FIGS. 1 to 3 to the open state shown in FIGS. It will be. The compressed air pressure acting on the second pressure receiving surface S2 is mainly determined by the value of the gap c between the inner wall surface of the side wall portion 18 of the cylinder portion 14 and the peripheral surface of the piston portion 25. The size of the gap c can be set to 0.05 mm, for example.

  The relief valve of the present invention can maintain the system pressure at a predetermined pressure continuously because the valve opening pressure does not change even when the valve is opened and closed multiple times. Further, the relief valve of the present invention can reduce the pressure of the system to a predetermined pressure in a short time, so that the pressure of the system can be more accurately maintained at the set pressure.

It is sectional drawing of one Example of the relief valve of this invention in a valve closing state. It is a principal part expanded sectional view of the relief valve of FIG. It is an expanded sectional view of the X section of FIG. It is sectional drawing of the relief valve of FIG. 1 in a valve opening state. It is a principal part expanded sectional view of the relief valve of FIG. It is an expanded sectional view of the Y part of FIG. FIG. 5 is a cross-sectional view of the relief valve of FIG. 1 in a transition state between the valve closed state of FIG. 1 and the valve open state of FIG. 4. It is a principal part expanded sectional view of the relief valve of FIG. 9A is a cross-sectional view when the Z portion of FIG. 8 is in a valve-closed state, and FIG. 9B is an enlarged cross-sectional view of the Z portion of FIG.

Explanation of symbols

1 Relief valve 2 Valve box 3 Adapter member 4 Set pressure adjusting member 5 Valve stem (valve element)
6 Compression coil spring 7 Lock nut 8 Primary port 9 Secondary port 11 Primary port opening 12 Annular groove 13 Annular seal member (valve seat member)
S1 First pressure-receiving surface S2 Second pressure-receiving surface CA Center axis

Claims (4)

A primary port and a secondary port are formed in the valve box of the relief valve, and a member having a cylinder part and a member having a piston part are attached to the valve box, and the cylinder part is downstream of the primary port. The piston portion is disposed between the opening on the side and the opening on the upstream side of the secondary port, and the piston portion reciprocates toward the opening on the downstream side of the primary port. The piston portion is slidably engaged with the cylinder portion, and the piston portion faces the opening on the downstream side of the primary port so that the piston portion blocks the primary port and the secondary port. Spring means for constantly energizing and receiving the fluid pressure of the primary side port, and when the piston portion moves a predetermined distance in a direction against the elastic force of the spring means, the primary side port is Configured to communicate with the secondary port In the relief valve, an annular groove is formed in the valve box so as to surround the opening on the upstream side of the primary port and open toward the cylinder, and the annular groove is made of an elastic material. A configured annular seal member is fitted, the annular seal member is protruded toward the cylinder part from the downstream side opening of the primary port, and the bottom of the cylinder part is crimped to the annular seal member. A through-hole is formed in the bottom of the cylinder portion, which opens toward the opening on the downstream side of the primary port and exposes the inner peripheral edge of the annular seal member, A projecting portion that protrudes and appears in the through hole is formed on the end surface on the primary port side, the projecting portion enters the through hole, and the piston portion of the cylinder portion is caused by the elastic force of the spring means. When closely attached to the bottom, The position of the piston portion is regulated by the cylinder portion, the projection portion is crimped to the inner peripheral edge portion of the annular seal member, and the primary port is disposed inside the contact portion of the projection portion and the annular seal member. A relief valve characterized by defining a pressure receiving surface for fluid pressure. The relief valve according to claim 1, wherein a through-hole that opens toward an opening on the upstream side of the secondary port is formed in a side wall portion of the cylinder portion, and the piston portion is connected to the primary port. When the fluid pressure is received and moved by a predetermined distance in the direction against the elastic force of the spring means, the through hole in the side wall portion of the cylinder portion is opened, and the fluid pressure in the primary port is changed to the secondary pressure. Said relief valve being opened to a side port. 3. The relief valve according to claim 1, wherein the piston portion further extends to an outer surface of the projecting portion on an end surface of the piston portion on the primary port side, and the piston portion is The relief valve having a second pressure receiving surface that receives the fluid pressure of the primary side port when separated from the annular seal member. 4. The relief valve according to claim 3, wherein when the fluid pressure of the primary port increases and the adhesion force between the piston portion and the annular seal member decreases, the piston portion separates from the annular seal member. The relief valve according to claim 1, wherein a part of the fluid pressure of the primary port acts on the second pressure receiving surface before.

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