Actuators and valves

Abstract

The objective of this invention is to provide an actuator and valve that can suppress the reduction of O-ring sealing performance even when used in high-temperature environments and can be used for a long time. The means to solve the problem is an actuator (20) comprising: a housing (lower housing (21) and upper housing (22)); a drive member (rod (24), piston (25) and support (24A)) disposed inside the housing and forming a pressure chamber (25e) together with the housing, and driven by an actuating fluid from the outside; and an annular sealing member (first O-ring (28A) to fifth O-ring (28E)) disposed inside the housing in a direction orthogonal to the direction of movement of the drive member, in a manner that abuts against only one of the housing and the drive member or not against either, and which, according to the movement of the drive member, seals the pressure chamber (25e) by crushing the drive member and the housing in the direction of movement.

Description

[Technical Field]

[0001] The present invention relates to actuators and valves used in semiconductor manufacturing apparatuses, etc. [Previous Technology]

[0002] In the valve described in Patent Document 1, which is opened and closed by an actuating fluid, an O-ring is provided between the piston and the outer casing to maintain the sealing of the pressure chamber. [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent No. 7365033 [Summary of the Invention]

[0004] [Problem to be Solved by the Invention] However, in the valve of Patent Document 1, the O-ring's sealing performance is achieved by the O-ring abutting against a direction orthogonal to the vertical direction. Therefore, when the valve is used for a long time in a high-temperature environment, the lubricating oil evaporates and the O-ring expands, causing the O-ring to wear due to slippage, resulting in a decrease in the O-ring's sealing performance. If the O-ring's sealing performance decreases, the actuating fluid leaks from the pressure chamber, causing the actuator to stop working and the valve to become inoperable. As a result, the valve needs to be replaced in a short period of time.

[0005] Therefore, one of the objectives of this invention is to provide an actuator and valve that can suppress the reduction of O-ring sealing performance even when used in high-temperature environments and can be used for extended periods. [Technical Means for Solving the Problem]

[0006] In order to achieve the aforementioned objective, one aspect of the actuator of the present invention comprises: a housing; a drive member disposed within the housing, forming a pressure chamber together with the housing, and driven by an actuating fluid from the outside; and an annular sealing member disposed within the housing in a direction orthogonal to the movement direction of the drive member, in a manner that abuts against only one of the housing and the drive member, or not against either, and thereby sealing the pressure chamber by the crushing of the drive member and the housing in the movement direction according to the movement of the drive member.

[0007] It may also include a guide bushing, which is supported in the aforementioned housing and supports the aforementioned drive member movable in the aforementioned moving direction.

[0008] Alternatively, the aforementioned driving member may have a piston, the aforementioned sealing member may have a plurality of sealing members, a portion of the plurality of sealing members may be disposed on the upper surface side of the aforementioned piston, and the remaining portion of the plurality of sealing members may be disposed on the lower surface side of the aforementioned piston.

[0009] One embodiment of the valve of the present invention comprises: a main body having a flow path; and the aforementioned actuator, which is mounted on the main body and can open and close the aforementioned flow path. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide an actuator and valve that can suppress the reduction of O-ring sealing even when used in high temperature environments and can be used for a long time.

Implementation Method

[0012] Referring to the figures, an actuator and valve according to a first embodiment of the present invention will be described. Figure 1 is a cross-sectional view of valve 1 in the closed state of the first embodiment. Furthermore, valve 1 in this embodiment is a diaphragm valve.

[0013] Valve 1 includes a main body 10 and an actuator 20. The type of valve is not particularly limited, but valve 1 in this embodiment is a so-called three-way valve. Furthermore, in the following description, the actuator 20 side of valve 1 will be described as the upper side and the main body 10 side of valve 1 as the lower side.

[0014] [Main Body 10] The main body 10 includes a main body 11, a seat 12 serving as a valve seat, a valve cap 13, a diaphragm 14, a pressing connector 15, and a diaphragm pressing member 16.

[0015] The main body 11 is roughly cubic. A valve chamber 11a, a first inflow path 11b, a second inflow path 11c, an outflow path 11d, and an annular groove 11e are formed in the main body 11. The first inflow path 11b branches into two flow paths (not shown), which communicate with the annular groove 11e. A resin seat 12 is annular and is located on the periphery of the portion of the main body where the second inflow path 11c communicates with the annular groove 11e.

[0016] The valve cap 13 is a slightly covered cylindrical shape, and is fixed to the body 11 by screwing its lower end onto the body 11 to cover the valve chamber 11a. The diaphragm 14, which is the valve body, is clamped and held at its outer periphery by a press-fit connector 15 disposed at the lower end of the valve cap 13 and the bottom surface of the valve chamber 11a forming the body 11. The opening and closing of the fluid passage is achieved by the diaphragm 14 separating from and abutting (pressing) against the seat 12.

[0017] The diaphragm pressing member 16 is provided on the upper side of the diaphragm 14 and is configured to press the central part of the diaphragm 14. The diaphragm pressing member 16 is fitted into the bracket 24A described later. The valve 1 is pressed by the compression coil spring 24B described later, via the bracket 24A, and is normally kept in the closed state (when the actuator 20 is not actuated).

[0018] [Actuator 20] The actuator 20 is gas-driven and is generally cylindrical. The actuator 20 includes: a lower housing 21, an upper housing 22, a first guide bushing 23A, a second guide bushing 23B, a rod 24, a support 24A, a compression coil spring 24B, a piston 25, a pressing member 26, an air gap 27, and a first O-ring 28A to a fifth O-ring 28E.

[0019] The lower outer casing 21 is a slightly stepped cylindrical shape, having a lower side portion 21A, a middle portion 21B, and an upper side portion 21C. The lower end portion 21A is screwed onto the outer periphery of the through hole at the upper end of the valve cap 13. A first through hole 21d is formed in the center of both the lower side portion 21A and the middle portion 21B. The lower portion of the first through hole 21d is wider than its upper portion. A first stepped portion 21E is provided on the inner peripheral surface of the lower side portion 21A. The upper end portion of the support 24A is inserted into the first through hole 21d. The support 24A is supported by the lower side portion 21A in a vertically movable manner. The middle portion 21B is slightly disc-shaped and has a first through hole 21d. An annular first recess 21f is formed on the inner peripheral surface of the middle portion 21B. The upper part 21C is in the shape of a ring and is arranged to protrude upward from the outer periphery of the middle part 21B.

[0020] The upper outer casing 22 is a slightly covered cylindrical shape, having an outer cylindrical portion 22A and an upper cover portion 22B. The outer cylindrical portion 22A is screwed onto the upper side portion 21C. Herein, the upper outer casing 22 is fixed to the lower outer casing 21. The upper cover portion 22B is provided to cover the upper end of the outer cylindrical portion 22A. A second through hole 22c is formed in the center of the upper cover portion 22B. The second through hole 22c is serrated. The upper cover portion 22B has a second stepped portion 22D. A disc-shaped second recess 22f is formed on the lower surface 22E of the upper cover portion 22B, surrounding the second through hole 22c. A leakage port 22g is formed on the upper cover portion 22B. The leakage port 22g opens to the outer portion of the second recess 22f on the lower surface 22E and to the outer peripheral surface of the upper cover portion 22B.

[0021] The first guide bushing 23A and the second guide bushing 23B are resin bearings and are cylindrical in shape. The first guide bushing 23A is located inside the upper part 21C of the lower housing 21. The second guide bushing 23B is located in the first recess 21f. The axial direction of the first guide bushing 23A and the second guide bushing 23B is consistent with the axial direction of the housing (lower housing 21 and upper housing 22) and the valve cap 13.

[0022] Rod 24 is provided in the first through hole 21d and is supported by the second guide bushing 23B, which allows it to move up and down. Rod 24 opens and closes the first inflow path 11b, the second inflow path 11c, and the outflow path 11d by moving close to and away from the diaphragm 14. The lower part of rod 24 is screwed into the upper recess of support 24A. Support 24A is slightly cylindrical and is arranged up and down within valve cap 13. Compression coil spring 24B is provided within valve cap 13, which keeps support 24A always pointing downwards.

[0023] The piston 25 is integrally formed with the rod 24 and is located on the upper side of the rod 24. The piston 25 has a base 25A, a first protrusion 25B, a second protrusion 25C, and a third protrusion 25D. The base 25A is slightly disc-shaped, and the rod 24 is integrally provided on its lower surface. The base 25A is supported by a first guide bushing 23A that allows it to move vertically. The rod 24, piston 25, and support 24A constitute a driving member.

[0024] The first protrusion 25B is slightly disc-shaped and protrudes upward from the upper surface of the base 25A. The outer diameter of the first protrusion 25B is larger than the inner diameter of the second recess 22f. The second protrusion 25C is slightly disc-shaped and protrudes upward from the upper surface of the first protrusion 25B. The third protrusion 25D is slightly cylindrical and extends upward from the upper surface of the second protrusion 25C, penetrating the second through hole 22c (upper cover 22B).

[0025] A pressure chamber 25e is formed by the lower surface of the base 25A and the upper surface of the middle portion 21B of the lower outer casing 21. An actuating fluid introduction path 25f is formed on the piston 25, extending from its upper end to the pressure chamber 25e. The actuating fluid introduction path 25f passes through the base 25A, the first protrusion 25B, the second protrusion 25C, and the third protrusion 25D, and branches into multiple paths at the base 25A.

[0026] The pressing member 26 is slightly cylindrical and has a third through hole 26a in its central part. A protrusion 26B protrudes into the third through hole 26a from the upper end of the pressing member 26. A portion of the inner diameter of the protrusion 26B in the third through hole 26a is smaller than the remaining portion. A third protrusion 25D is inserted into the lower part of the protrusion 26B in the third through hole 26a. The upper end of the third protrusion 25D is screwed into the third through hole 26a of the pressing member 26, and the pressing member 26 is fixed to the piston 25. Therefore, the pressing member 26 moves up and down together with the piston 25. The upper end of the third protrusion 25D abuts against the protrusion 26B. The lower part of the pressing member 26 is inserted into the second through hole 22c. A gap 26c is formed between the lower surface of the pressing member 26 and the upper surface of the second protrusion 22D.

[0027] The airport section 27 is a slightly stepped cylindrical shape and is fixed to the upper surface of the upper cover section 22B. A fourth through hole 27a is formed in the center of the airport section 27. The lower portion of the fourth through hole 27a is wider than its upper portion. The upper portion of the pressing member 26 is inserted into the lower portion of the fourth through hole 27a. The pressing member 26 is supported by the upper cover section 22B and the airport section 27, allowing it to move vertically. The fourth through hole 27a communicates with the actuating fluid inlet path 25f via the third through hole 26a. An actuating fluid supply source (not shown) is connected to the airport section 27 via a pipe fitting and metal piping (not shown).

[0028] The first O-ring 28A is disposed around the third protrusion 25D, i.e., in the gap 26c. When the valve 1 is closed, the first O-ring 28A is crushed by the pressing member 26 and the second step portion 22D, sealing the space between the air section 27 and the air chamber (the space between the lower side of the upper outer shell 22 and the upper side of the base 25A). The second O-ring 28B is disposed around the outer periphery of the second protrusion 25C. When the valve 1 is open, the second O-ring 28B is crushed by the lower surface of the second recess 22f of the upper outer shell 22 and the upper surface of the first protrusion 25B, sealing the space between the air section 27 and the air chamber. The third O-ring 28C is disposed around the outer periphery of the first protrusion 25B. When the valve 1 is open, the third O-ring 28C is crushed by the lower surface 22E of the upper outer shell 22 and the upper surface of the base 25A, sealing the pressure chamber 25e.

[0029] The fourth O-ring 28D is disposed around the rod 24 in the pressure chamber 25e. When the valve 1 is closed, the fourth O-ring 28D is crushed by the lower surface of the base 25A and the upper surface of the intermediate portion 21B, sealing the pressure chamber 25e. The fifth O-ring 28E is disposed around the rod 24 and between the upper end of the support 24A and the first step difference portion 21E. When the valve 1 is open, the fifth O-ring 28E is crushed by the upper end of the support 24A and the lower surface of the first step difference portion 21E, sealing the pressure chamber 25e.

[0030] The first O-ring 28A to the fifth O-ring 28E are disposed within the housing in a direction orthogonal to the moving direction (vertical direction) of the piston 25, abutting only one of the housing (lower housing 21 and upper housing 22) and the piston 25, or not abutting either one. That is, the first O-ring 28A to the fifth O-ring 28E are in a direction orthogonal to the moving direction (vertical direction) of the piston 25 and are not pressed by both the housing and the piston 25. When crushed, the first O-ring 28A to the fifth O-ring 28E abut only one of the housing and the piston 25, or not abutting either one. The first O-ring 28A to the fifth O-ring 28E function as sealing members.

[0031] Next, the opening and closing operation of valve 1 in this embodiment will be explained. Figure 2 is a cross-sectional view of the actuator 20 of valve 1 in the open state.

[0032] As shown in Figure 1, in the closed state of valve 1, the actuating fluid does not flow into the pressure chamber 25e. The rod 24 and piston 25 are located at the bottom dead center (close to the main body 11) by the spring force of the compression coil spring 24B, and the diaphragm 14 is pressed by the diaphragm pressing member 16. That is, valve 1 is in the closed state in the normal state (the state in which the actuating fluid is not supplied). In the closed state of valve 1, the first inflow path 11b and the outflow path 11d are connected via the annular groove 11e.

[0033] The actuating fluid is supplied to valve 1 from an actuating fluid supply source (not shown). Actuating fluid is supplied to valve 1. The actuating fluid flows into pressure chamber 25e through a metal pipe and fitting (not shown), via the fourth through hole 27a, the third through hole 26a, and the actuating fluid inlet path 25f. As shown in FIG2, piston 25 rises against the spring force of compression coil spring 24B. As a result, support 24A and rod 24 move towards the upper dead center (separating from body 11), and diaphragm pressing member 16 moves upward by the elastic force of diaphragm 14 and the pressure of fluid (gas), connecting via the second inlet path 11c and outlet path 11d through an annular groove 11e, thus opening valve 1.

[0034] When valve 1 is fully closed, the first O-ring 28A seals the spacer section 27 and the air chamber, and the fourth O-ring 28D seals the pressure chamber 25e, thus preventing leakage of the operating fluid from the fully closed to the fully open position of valve 1. When valve 1 is fully open, the second O-ring 28B seals the spacer section 27 and the air chamber, thus preventing leakage of the operating fluid from the spacer section 27 to the air chamber. When valve 1 is fully open, the third O-ring 28C and the fifth O-ring 28E seal the pressure chamber 25e, thus preventing leakage of the operating fluid from the pressure chamber 25e to the outside.

[0035] To change valve 1 from the open state to the closed state, the three-way valve (not shown) can be switched to allow the actuating fluid to flow from the actuator 20 (pressure chamber 25e) of valve 1 to the outside. Here, the actuating fluid in pressure chamber 25e is discharged to the outside via the actuating fluid inlet path 25f. Here, rod 24 and piston 25 move downwards to their dead center by the spring force of compression coil spring 24B, and valve 1 becomes closed (Fig. 1).

[0036] According to the aforementioned actuator 20, the first O-ring 28A to the fifth O-ring 28E are disposed within the housing in a direction orthogonal to the movement direction of the drive member (rod 24, piston 25, and support 24A), abutting only one of the housing (lower housing 21 and upper housing 22) and the drive member, or not abutting either. Based on the movement of the drive member, the pressure chamber 25e is sealed by the crushing of the drive member and the housing in the movement direction. Thus, the first O-ring 28A to the fifth O-ring 28E will not slide against the housing or other components, but will only be crushed. As a result, even under prolonged use in high-temperature environments, wear caused by sliding of the first O-ring 28A to the fifth O-ring 28E can be suppressed, and the reduction in the sealing performance of the first O-ring 28A to the fifth O-ring 28E can be suppressed. Therefore, leakage of the operating fluid from the pressure chamber 25e can be prevented. This allows for a longer service life of valves used in high-temperature environments.

[0037] The drive member is movably supported in the moving direction by the first guide bushing 23A and the second guide bushing 23B, thus allowing the shaft of the housing to be aligned with the shaft of the drive member. The first O-ring 28A to the third O-ring 28C are provided on the upper surface of the piston 25, and the fourth O-ring 28D to the fifth O-ring 28E are provided on the lower surface of the piston 25. This prevents leakage of the actuating fluid from the pressure chamber 25e to the outside during the transition from fully closed to fully open of the valve 1. This, in turn, extends the service life of the valve used in high-temperature environments.

[0038] Next, referring to the figures, the actuator and valve of the second embodiment of the present invention will be described. Figure 3 is a cross-sectional view of the actuator 120 of the valve 101 in the closed state of the second embodiment. Figure 4 is a cross-sectional view of the actuator 120 of the valve 101 in the open state of the second embodiment. Components identical to those in the actuator 20 of the first embodiment are given the same reference numerals and their descriptions are omitted here.

[0039] The actuator 120 of this embodiment does not have the pressing member 26 of the first embodiment. The actuation part 127 is screwed into the third protrusion 25D of the piston 125. The second through hole 122c formed in the upper cover part 122B of the upper housing 122 is cylindrical rather than serrated. The piston 125 does not have the second protrusion 25C of the first embodiment, but has a third protrusion 25D in the first protrusion 25B. The actuation part 127 is a slightly stepped cylindrical shape, and the third protrusion 25D is inserted into the enlarged portion of the fourth through hole 127a. The upper end of the third protrusion 25D is screwed into the fourth through hole 127a, and the actuation part 127 is fixed to the piston 125. Therefore, the actuation part 127 and the piston 125 move up and down together. The upper end of the third protrusion 25D abuts against the third stepped portion 127B. The lower part of the airport section 127 is inserted into the second through hole 122c.

[0040] In this embodiment, the second O-ring 28B of the first embodiment is not provided in the actuator 120, and the sealing member is composed of the first O-ring 28A and the third O-rings 28C to the fifth O-rings 28E. As shown in Figures 3 and 4, when the valve 101 is fully open or closed, the first O-ring 28A is always crushed by the lower end of the airfield section 127 and the upper surface of the first protrusion 25B. The first O-ring 28A seals the airfield section 127 and the air chamber.

[0041] The actuator 120 of this embodiment can also achieve the same effect as the actuator 20 of the first embodiment. Furthermore, the number of O-rings can be reduced according to the actuator 120.

[0042] Furthermore, the present invention is not limited to the foregoing embodiments. Those skilled in the art can make various additions or modifications within the scope of the present invention.

[0043] For example, in the aforementioned embodiment, the drive member is supported by the first guide bushing 23A and the second guide bushing 23B. However, the first guide bushing 23A and the second guide bushing 23B may not be provided. Instead, a coating with excellent sliding properties may be applied to the inner circumferential surface of the housing, and the drive member may be supported by the inner circumferential surface in a way that allows for vertical movement. Two first guide bushings 23A and two guide bushings 23B are provided, but only one of them may be provided. A recess may also be provided on the upper surface of the middle portion 21B of the lower housing 21, where the fourth O-ring 28D is placed. The first O-ring 28A to the fifth O-ring 28E are provided inside the housing in a direction orthogonal to the moving direction (vertical direction) of the drive member, abutting only one of the housing and the piston, or not abutting either one. However, at least one of the 1st O-ring 28A to the 5th O-ring 28E may be disposed within the housing in a direction orthogonal to the direction of movement (up and down) of the driving member, abutting only one of the housing and the piston, or not abutting either one. [Simplified Explanation of the Diagram]

[0011] [Fig. 1] is a cross-sectional view of the valve in the closed state according to the first embodiment. [Fig. 2] is a cross-sectional view of the actuator of the valve in the open state according to the first embodiment. [Fig. 3] is a cross-sectional view of the actuator of the valve in the closed state according to the second embodiment. [Fig. 4] is a cross-sectional view of the actuator of the valve in the open state according to the second embodiment.

Claims

1. An actuator comprising: a housing; a drive member disposed within the housing, forming a pressure chamber together with the housing, and driven by an actuating fluid from the outside; and an annular sealing member disposed within the housing in a direction orthogonal to the direction of movement of the drive member, wherein the sealing member abuts against only one of the housing and the drive member, or not against either, and thereby seals the pressure chamber by the crushing of the drive member and the housing in the direction of movement according to the movement of the drive member.

2. The actuator as claimed in claim 1, wherein, It also has a guide bushing, which is supported inside the aforementioned housing, and supports the aforementioned drive member movable in the aforementioned moving direction.

3. The actuator as described in claim 1 or 2, wherein, The aforementioned driving member has a piston, the aforementioned sealing member has a plurality of sealing members, a portion of the aforementioned plurality of sealing members is disposed on the upper surface side of the aforementioned piston, and the remaining portion of the aforementioned plurality of sealing members is disposed on the lower surface side of the aforementioned piston.

4. A valve comprising: a body having a flow path; and an actuator as described in any one of claims 1 to 3, which is mounted on the aforementioned body and can open or close the aforementioned flow path.

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