JP2008276630A - Pressure reducing valve - Google Patents

Abstract

Disclosed is a pressure reducing valve in which an external pressure receiving surface on which a pressure outside a fluid passage acts is formed on a valve body, and a pressure reducing valve in which no residual pressure remains on the secondary side of the fluid passage.
The pressure outside the valve chamber 41 is applied to the valve body 42 so as to reduce the force with which the valve body 42 is pressed against the valve seat 19 by the pressure of the fluid supplied to the primary side port 7 of the pressure reducing valve 1. An atmospheric pressure receiving surface 44 on which is applied is formed. A spring load is applied to the valve spring 43 to complement the seat pressure reduced by forming the atmospheric pressure receiving surface 44. A bypass passage 23 that connects the secondary side of the fluid passage of the pressure reducing valve 1 to the primary side is formed, and the fluid passage is closed by the valve body 42 being in close contact with the 19 valve seat, and the fluid pressure on the primary side When the pressure is lower than the fluid pressure on the secondary side, the fluid is discharged from the secondary side of the fluid passage to the primary side via the bypass passage 23.
[Selection] Figure 2

Description

  The present invention relates to a pressure reducing valve that reduces the pressure of a fluid supplied from an air compressor or the like to a desired pressure.

  Conventionally, when using an air tool driven by compressed air such as a nailer or an air impact driver, a pressure reducing valve is attached to the discharge line of the air tank of the air compressor. By setting the side pressure to a desired value, high-pressure compressed air is supplied to high-pressure air tools driven by high-pressure air, and low-pressure compressed air is supplied to low-pressure air tools driven by low-pressure air. is doing. Of the air compressors used to drive air tools, portable air compressors are generally carried into the work site and used. When the day's work is completed, the pressure of the air tank is released and the air compressor is removed from the work site. It is carried out. When using a specific air tool for several days, the air tool is often left connected to the air compressor when the day's work is completed. Therefore, when the work of the day is completed and the pressure of the air tank is released, not only the pressure on the primary side of the pressure reducing valve is released but also the pressure on the secondary side needs to be released. This is because the air tool may malfunction due to the residual pressure on the secondary side of the pressure reducing valve.

For example, Japanese Patent No. 3358428 discloses a pneumatic regulator to be mounted on an air tool body. This air pressure regulator changes the spring pressure of the pressure adjusting spring 16 interposed between the cylinder 4 and the piston 5 by rotating the pressure adjusting screw 7 screwed into the cylinder 4, and the secondary air pressure. Is a pressure reducing valve configured to set a desired value. That is, the high-pressure compressed air supplied to the spring chamber 6 b of the poppet valve holder 6 via the air plug 3 is a poppet energized in the direction of the valve seat 21 by the valve seat 21 surrounding the port 18 and the pressure spring 20. 19 is opened and closed by a piston 5 that responds to the air pressure on the secondary side, thereby reducing the pressure to a preset secondary side pressure. When the work is finished and the air hose is removed from the air plug 3, the spring chamber 6 b of the poppet valve holder 6 becomes atmospheric pressure, and the piston 5 biased by the pressure adjusting spring 16 strikes the spring force of the pressure spring 20. Win the poppet 18 away from the valve seat 21. As a result, the port 18 is opened and the secondary air pressure is reduced to atmospheric pressure.
Japanese Patent No. 3358428

  The applicant of the present application states that the pressure of the fluid supplied to the primary side of the fluid passage causes the valve body to be in close contact with the valve seat, and the pressure of the fluid supplied to the primary side of the fluid passage is the valve body. We proposed a pressure control valve characterized in that an external pressure receiving surface on which the pressure outside the fluid passage acts was formed on the valve body so that the forces that would cause the valve to separate from the valve seat would cancel each other out. Application No. 2005-319520). In this way, the external pressure receiving surface is formed so that the two-direction forces acting on the valve body cancel each other, but depending on the purpose of use of the pressure control valve, these two-direction forces need to be canceled exactly. There may be no. For example, this pressure control valve is used as a pressure reducing valve attached to the discharge port of an air tank of an air compressor in order to supply compressed air to an air tool. In such a pressure reducing valve, when the fluid pressure on the primary side fluctuates, if the variation in the fluid pressure on the secondary side falls within a predetermined range, there is often no problem in driving the air tool.

  Now, comparing the pressure reducing valve in which atmospheric pressure acts on the external pressure receiving surface of the valve body and a general pressure reducing valve that does not have an external pressure receiving surface (atmospheric pressure receiving surface) on the valve body, the valve in the former pressure reducing valve The seat pressure of the body and the valve seat is smaller than the seat pressure of the latter pressure reducing valve by the primary side pressure acting on the external pressure receiving surface (atmospheric pressure receiving surface). If the seat pressure of the valve body and the valve seat is insufficient, the primary side and secondary side shut-off properties of the fluid passage are deteriorated, so that the secondary side pressure cannot be appropriately controlled. For this reason, a spring having a larger spring load than the valve spring of a general pressure reducing valve is used as the valve spring of the former pressure reducing valve to compensate for the decrease in seat pressure. However, when a valve spring with a large spring load is used, the use of the pressure reducing valve is terminated, and the valve body is brought into close contact with the valve seat by the resilient force of the valve spring even when the pressure on the primary side of the pressure reducing valve is released. The pressure on the secondary side of the pressure reducing valve may remain as a residual pressure on the secondary side of the fluid passage.

  An object of the present invention is to provide an external pressure receiving surface on which a pressure outside the fluid passage acts on the valve body so as to reduce the force with which the valve body is pressed against the valve seat by the pressure of the fluid supplied to the primary side of the fluid passage. It is an object of the present invention to provide a pressure reducing valve in which no residual pressure remains on the secondary side of the fluid passage.

  Another object of the present invention is to provide an external pressure at which the pressure outside the fluid passage acts on the valve body so as to reduce the force with which the valve body is pressed against the valve seat by the pressure of the fluid supplied to the primary side of the fluid passage. An object of the present invention is to provide a pressure reducing valve capable of appropriately setting a seat pressure in a pressure reducing valve having a pressure receiving surface.

  Still another object of the present invention is to provide a pressure reducing valve that is simple in structure, easy to downsize, and highly versatile.

  The pressure reducing valve of the present invention is disposed on the primary side of the fluid passage, the fluid passage for guiding the fluid supplied to the primary side to the secondary side, the valve seat formed in the fluid passage, and A valve body that regulates the size of the cross-sectional area of the fluid passage in cooperation with the valve seat, a valve spring that regulates the seat pressure of the valve body and the valve seat, and a secondary side of the fluid passage. And a valve body driving member that displaces the valve body with respect to the valve seat in accordance with a pressure fluctuation on the secondary side of the fluid passage, and a pressure that biases the valve body driving member toward the valve body A pressure reducing valve that discharges the fluid supplied to the primary side of the fluid passage and discharges the fluid to the secondary side. The pressure is reduced by the pressure of the fluid supplied to the primary side of the fluid passage. The fluid is passed through the valve body so as to reduce the force with which the valve body is pressed against the valve seat. An external pressure receiving surface on which an external pressure acts is formed, a spring force that complements the seat pressure reduced by the external pressure receiving surface is applied to the valve spring, and the secondary side of the fluid passage is set to the primary side. When a bypass passage to be connected is formed, the valve body is in close contact with the valve seat, the fluid passage is closed, and the fluid pressure on the primary side is lower than the fluid pressure on the secondary side The fluid is discharged from the secondary side to the primary side through the bypass passage.

  In the pressure reducing valve of the present invention, a separator is inserted into the fluid passage, the separator defines the fluid passage into a primary side and a secondary side, and an outer surface of the separator and an inner wall of the fluid passage The bypass passage is defined between the separator, an annular groove extending along the bypass passage is formed on the outer surface of the separator, and an annular check valve is fitted into the annular groove. When the valve body is in close contact with the valve seat, the communication path is blocked, and when the fluid pressure on the primary side of the fluid path is lower than the fluid pressure on the secondary side, the bypass path is The fluid is allowed to flow from the secondary side to the primary side of the fluid passage.

  The pressure reducing valve of the present invention further includes a communication passage that allows the primary side and the secondary side of the fluid passage to communicate with the separator, and an opening portion of the communication passage is formed on an end surface of the primary side of the separator. The valve seat surrounding the opening is formed, and the check valve is formed of an annular elastic body having a Y-shaped cross-sectional shape.

  According to the pressure reducing valve of the present invention, when the fluid pressure on the primary side becomes lower than the fluid pressure on the secondary side, even if the fluid passage is closed by the valve body being in close contact with the valve seat, Since the secondary side communicates with the primary side of the fluid passage via the bypass passage, when the fluid pressure on the primary side of the fluid passage is set to atmospheric pressure, the fluid pressure on the secondary side also becomes atmospheric pressure. Therefore, even if the air tool or the like is connected to the secondary side of the pressure reducing valve, it is possible to reliably prevent the air tool or the like from malfunctioning due to the residual pressure on the secondary side of the fluid passage.

  Further, according to the pressure reducing valve of the present invention, the residual pressure on the secondary side of the fluid passage can be eliminated regardless of the magnitude of the spring load of the valve spring. Therefore, the spring load of the valve spring can be freely increased or decreased. The seat pressure of the valve body and the valve seat can be set appropriately.

  The pressure reducing valve of the present invention communicates the secondary side of the fluid passage to the primary side between the outer surface of the separator that defines the fluid passage on the primary side and the secondary side and the wall surface of the fluid passage. A bypass passage can be formed. Since this bypass passage is formed only by inserting the separator into the fluid passage, there is no need to newly process the bypass passage in the valve housing of the pressure reducing valve. Further, if an annular groove extending along the bypass passage is formed on the outer surface of the separator and an annular check valve is attached to the annular groove, the bypass passage can be formed only by inserting the separator into the fluid passage. And the check valve can be arranged at the same time.

  Furthermore, in the pressure reducing valve of the present invention, the area of the portion surrounded by the outer edge of the close contact portion between the valve body and the valve seat and the area of the external pressure receiving surface can be set arbitrarily. Therefore, the force (seat pressure based on the primary side pressure) by which the valve body is pressed against the valve seat by the primary side fluid pressure can be adjusted, and the fluctuation of the primary side fluid pressure can be adjusted to the secondary side fluid. The effect on pressure can be adjusted.

  Other features of the pressure reducing valve of the present invention will become apparent from the description of the following examples. Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows an embodiment in which the present invention is applied to a direct acting pressure reducing valve. The direct-acting pressure reducing valve 1 is attached to a discharge port 5 of an air tank 3 associated with a portable air compressor 2, and high pressure compressed air discharged from the air tank 3 is set to a preset pressure (hereinafter referred to as a set pressure). It is an air pressure reducing valve that is depressurized to supply the air tool 5 such as a nailer.

  A primary side port 7 and a secondary side port 8 are opened on the side surface of the valve housing 6 of the pressure reducing valve 1. The primary port 7 is connected to the discharge port 4 of the air tank 3, and the secondary port 8 is connected to the air tool 5 via a flexible air hose 9. A central through hole 10 is also formed in the valve housing 6, and the primary port 7 is connected to the central through hole 10 via the communication path 11. A communication groove 13 that opens to the upper large diameter portion 12 of the central through hole 10 is formed outside the central through hole 10 of the valve housing 6, and the secondary port 8 is connected to the communication groove 13.

  A separator 14 is fitted into the central through hole 10 of the valve housing 6. As shown in FIGS. 4 and 5, the separator 14 penetrates the protruding portion 17 from the cylinder portion 16, the cylinder portion 16 into which the piston 15 is slidably fitted, the protruding portion 17 fitted into the central through hole 10, and the like. Thus, the communication passage 18 that opens to the lower end surface of the projecting portion 17 and the valve seat 19 that surrounds the opening portion of the communication passage 18 are provided, and the protruding portion 20 of the piston 15 extends inside the communication passage 18. An annular groove 21 is formed on the outer surface of the projecting portion 17, and an annular elastic body 22 having a Y-shaped cross section is attached to the annular groove 21. As shown in FIG. 3, an annular bypass passage 23 is formed between the outer surface of the protrusion 17 and the wall surface of the central through hole 10 of the valve housing 6, and the annular elastic body 22 is interposed in the bypass passage 23. The The annular elastic body 22 has an annular tongue piece 24. The annular tongue piece 23 abuts against the wall surface of the central through hole 10, and allows fluid to flow in the direction of the arrow in FIG. 3, while fluid flows in the opposite direction. Stop that. The overall shape of the annular elastic body 22 is as shown in FIG. The annular tongue piece 24 of the annular elastic body 22 constitutes a check valve. 1 and 2, reference numerals 25 and 26 denote sealing rings for sealing.

  As shown in FIGS. 1 and 2, the piston 15 is formed with a relief passage 27 extending along the central axis thereof. The relief passage 27 is formed on the back surface 28 of the piston 15 and the tip portion 29 of the protrusion 20 of the piston 15. And open. A bonnet 30 is fixed to the upper portion of the valve housing 6 by a bolt (not shown). The separator 14 is sandwiched and fixed between the valve housing 6 and the bonnet 30. A pressure adjusting bolt 31 is screwed into the bonnet 30, and the pressure adjusting bolt 31 is rotated by a pressure adjusting knob 32. A spring receiver 33 is engaged with the lower end of the pressure adjusting bolt 31, and a pressure setting spring 36 is interposed between the spring receiver 33 and the piston 15. In FIG. 1, reference numeral 37 indicates an opening for communicating the inside and outside of the bonnet 30.

  As shown in FIGS. 1 and 2, a plug body 38 is attached to the lower portion of the valve housing 6 by screwing into the central through hole 10 of the valve housing 6. Reference numeral 39 indicates a sealing ring for sealing interposed between the central through hole 10 and the plug body 38. A through hole 40 is formed in the central portion of the plug body 38 so that the projection 20 of the piston 15 and the shaft center coincide with each other. By attaching the plug body 38 to the valve housing 6, the valve chamber 41 is defined on the upstream side of the valve seat 19 of the central through hole 10. A valve body 42 and a valve spring 43 are disposed in the valve chamber 41, and the valve spring 43 is interposed between the valve body 42 and the plug body 38. The lower end portion of the valve body 42 is slidably inserted into the through hole 40 of the plug body 38, and the valve body 42 is supported by the through hole 40 of the plug body 38 so as to be movable in the vertical direction in FIGS. . A lower end surface 44 of the valve body 41 is exposed to the outside of the valve chamber 41 from the through hole 40 of the plug body 38 to form an atmospheric pressure receiving surface 44. Reference numeral 45 indicates a sealing ring for sealing interposed between the lower end of the valve body 41 and the through hole 40 of the plug body 38.

  As shown in FIG. 2, when the valve body 41 is seated on the valve seat 19 of the separator 14, the area surrounded by the outer diameter of the close contact portion between the valve body 42 and the valve seat 19 is A. Further, the area of the atmospheric pressure receiving surface 44 exposed from the through hole 40 of the plug body 38 is B. Now, assuming that the primary pressure of the compressed air flowing into the primary port 7 from the air tank 3 is P1, the upward force received by the valve body 42 by the primary pressure P1 is expressed as P1 · A. The downward force received by the valve body 42 by the side pressure P1 is represented by P1 · B. Accordingly, the force received by the valve body 42 by the primary pressure P1 is (P1 · A−P1 · B), and the seat pressure of the valve body 41 and the valve seat 19 is reduced by P1 · B by the formation of the atmospheric pressure receiving surface 44. Will be. Therefore, by increasing the spring load of the valve spring 43, the seat pressure of the valve body 41 and the valve seat 19 is set appropriately. The purpose of forming the atmospheric pressure receiving surface 44 on the valve body 41 is to reduce the influence of the pressure fluctuation of the primary side pressure P1 on the operation of the valve body 41, thereby reducing the fluctuation of the secondary side pressure. Therefore, in selecting the spring load of the valve spring 43, the optimum spring load should be selected for the pressure reducing valve by comprehensively considering the primary side pressure P1, the secondary side pressure P2, and the areas A and B. It is.

The operation of the present invention will be described below based on the usage mode of FIG.
First, the pressure adjusting knob 32 is rotated to change the spring load of the pressure setting spring 36 so that the set pressure of the pressure reducing valve 1 becomes a set pressure suitable for the air tool 5. Next, the air compressor 2 is started and work is performed using the air tool 5. At this time, the piston 15 is lowered by the spring load of the pressure setting spring 36 to push down the valve body 42. Therefore, the high-pressure compressed air generated by the air compressor 2 flows into the valve chamber 41 from the primary side port 7 through the communication path 11, passes through the valve seat 19 and flows into the communication path 18, and 18 flows into the annular flow path 56 and reaches the secondary port 8 through the communication groove 13. Here, the primary side port 7, the communication path 11, and the valve chamber 41 constitute a primary side fluid path, and the communication path 18, the annular flow path 56, the communication groove 13, the secondary side port 8, and the air hose 9 and the air tool 5 constitute a secondary fluid passage. When high-pressure compressed air flows from the primary fluid passage into the secondary fluid passage, the compressed air flows from the communication passage 18 into the cylinder portion 16, and resists the elastic force of the pressure setting spring 36. Raise 15 When the air pressure in the secondary fluid passage reaches the set pressure, the valve element 42 is seated on the valve seat 19 to shut off the secondary fluid passage from the primary fluid passage. When the air pressure in the secondary side fluid passage is lower than the set pressure by using the air tool 5, the piston 15 descends and pushes down the valve body 42, and the valve body 42 is separated from the valve seat 19 to move to the primary side. Compressed air is supplied from the fluid passage to the secondary fluid passage. Thereafter, the above-described operation is repeated, and the air pressure in the secondary fluid passage is maintained at the set pressure. During this time, the air pressure on the primary side of the fluid passage is always higher than the air pressure on the secondary side, so that the bypass passage 23 is closed by the annular tongue 24 of the annular elastic body 22. Therefore, the compressed air does not flow from the primary side to the secondary side of the fluid passage through the bypass passage 23.

  When the work by the air tool 5 is completed, the operation of the air compressor 2 is stopped and the air tank 3 is evacuated. At this time, since the primary side port 7 of the pressure reducing valve 1 is connected to the discharge port 4 of the air tank 3, when the inside of the air tank 3 reaches zero pressure, the primary side of the fluid passage of the pressure reducing valve 1 also becomes zero pressure. Become. However, since the spring load of the valve spring 43 is increased with the formation of the atmospheric pressure receiving surface 44 on the valve body 42 of the pressure reducing valve 1, depending on the spring load of the valve spring 43, the inside of the air tank 3 may be Even when the pressure becomes zero, the valve body 43 may be seated on the valve seat 19 by the spring force of the valve spring 43, and the communication path 18 may be closed. In this state, the annular tongue 24 of the annular elastic body 22 that has closed the bypass passage 23 is opened, and the fluid is discharged from the secondary side of the fluid passage to the primary side as shown by → in FIG. . Thereby, the residual pressure is immediately discharged to the secondary side of the fluid passage, and it is possible to prevent the air tool 5 from malfunctioning due to the residual pressure on the secondary side of the fluid passage.

  When the air tool 5 is used, if the air pressure on the secondary side of the fluid passage reaches a relief pressure higher than the set pressure for some reason, the piston 15 is raised and the valve body 42 is seated on the valve seat 19. Thereafter, the piston 15 is further raised and separated from the valve body 42. As a result, the relief passage 27 is opened, the secondary side of the fluid passage is communicated with the atmosphere from the opening 37 of the bonnet 30, and the secondary side of the fluid passage is exhausted. In the above-described embodiment, the piston 15 is exemplified as the valve body driving member. However, the valve body driving member is not limited to the piston. For example, a member such as a diaphragm is provided on the secondary side of the fluid passage. Any member may be used as long as it can drive the valve body in accordance with the fluid pressure.

  The pressure reducing valve of the present invention can be easily reduced in size and weight, and since no residual pressure remains on the secondary side of the fluid passage, it can be used not only for driving an air tool but also for various applications. it can.

It is the longitudinal cross-sectional view which illustrated the usage aspect of the pressure control valve of this invention. It is sectional drawing to which the principal part of the pressure control valve of FIG. 1 was expanded. It is an expanded sectional view near Y packing mounting part. It is sectional drawing which notched a part of separator. It is a top view of a separator. It is a longitudinal cross-sectional view of Y packing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pressure reducing valve 2 Air compressor 3 Air tank 5 Air tool 14 Separator 19 Valve seat 21 Annular groove 22 Annular elastic body 23 Bypass passage 24 Annular tongue piece 42 Valve body 43 Valve spring 44 External pressure receiving surface (atmospheric pressure receiving surface)
A Area surrounded by the outer diameter of the close contact part between the valve body and the valve seat B Area of the atmospheric pressure receiving surface

Claims (3)

  A fluid passage for guiding the fluid supplied to the primary side to the secondary side; a valve seat formed in the fluid passage; and a primary side of the fluid passage, and in cooperation with the valve seat A valve body that regulates the size of a cross-sectional area of the fluid passage, a valve spring that regulates a seat pressure of the valve body and the valve seat, a fluid passage disposed on the secondary side of the fluid passage, and the fluid passage; A valve body driving member for displacing the valve body with respect to the valve seat in accordance with a pressure fluctuation on the secondary side, and a pressure setting spring for biasing the valve body driving member toward the valve body, In the pressure reducing valve, the pressure supplied to the primary side of the fluid passage is decompressed and discharged to the secondary side, and the valve body is moved to the valve seat by the pressure of the fluid supplied to the primary side of the fluid passage. Pressure outside the fluid passage is exerted on the valve body to reduce the force applied. An external pressure receiving surface is formed, and a spring force that complements the seat pressure reduced by the external pressure receiving surface is applied to the valve spring to form a bypass passage that connects the secondary side of the fluid passage to the primary side. When the valve body is in close contact with the valve seat, the fluid passage is closed, and when the primary fluid pressure is lower than the secondary fluid pressure, the bypass passage is passed through the bypass passage. The pressure reducing valve discharges fluid from the secondary side to the primary side.   2. The pressure reducing valve according to claim 1, wherein a separator is inserted into the fluid passage, the separator defines the fluid passage into a primary side and a secondary side, and an outer surface of the separator and an inner wall of the fluid passage. The bypass passage is defined between the annular passage, an annular groove extending along the bypass passage is formed on the outer surface of the separator, and an annular check valve is fitted into the annular groove, When the valve body is in close contact with the valve seat, the communication passage is blocked, and when the fluid pressure on the primary side of the fluid passage is lower than the fluid pressure on the secondary side, the bypass passage The pressure reducing valve is characterized in that fluid is allowed to flow from the secondary side to the primary side of the fluid passage through the pipe.   3. The pressure reducing valve according to claim 2, wherein the separator is formed with a communication path that communicates a primary side and a secondary side of the fluid path, and an opening portion of the communication path is formed on an end surface of the separator on the primary side. And the valve seat surrounding the opening, and the check valve is formed of an annular elastic body having a Y-shaped cross-sectional shape.

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