Actuator and valve

Abstract

To provide an actuator and a valve which suppress decrease in sealing property of an O-ring and can be used for a long time even when used in a high-temperature environment.SOLUTION: An actuator 20 includes: a casing (lower casing 21 and upper casing 22); a drive member (stem 24, piston 25, and holder 24A) provided in the casing and forming a pressure chamber 25e along with the casing, and driven by work fluid from outside; and annular seal members (first to fifth O-rings 28A-28E) which are provided in the casing to be in contact with only one of the casing and the drive member or not to be in contact with either of them in a direction orthogonal to a movement direction of the drive member, and the seal members pressed with the movement of the drive member in the moving direction by the drive member and the casing to seal the pressure chamber 25e.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an actuator and a valve used in a semiconductor manufacturing device or the like. [Background technology]

[0002] In the valve disclosed in Patent Document 1, which opens and closes using a working fluid, an O-ring is provided between the piston and the case to maintain the sealing performance of the pressure chamber. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7365033 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the valve of Patent Document 1, the O-ring's sealing ability is achieved by the O-ring abutting in a direction perpendicular to the vertical direction. Therefore, if the valve is used in a high-temperature environment for a long period of time, the lubricating oil evaporates, causing the O-ring to expand. This causes the O-ring to wear due to sliding, and the O-ring's sealing ability deteriorates. When the O-ring's sealing ability deteriorates, working fluid leaks from the pressure chamber, causing the actuator to stop working and the valve to stop moving. As a result, the valve had to be replaced frequently.

[0005] Therefore, one object of the present disclosure is to provide an actuator and a valve that can be used for a long period of time, even when used in a high-temperature environment, by suppressing deterioration in the sealing performance of the O-ring. [Means for solving the problem]

[0006] In order to achieve the above object, one aspect of the present invention provides an actuator comprising: a casing; a drive member provided within the casing to form a pressure chamber together with the casing and driven by an external working fluid; and an annular sealing member provided within the casing so as to abut either or both of the casing and the drive member in a direction perpendicular to the direction of movement of the drive member, and which is crushed by the drive member and the casing in the direction of movement as the drive member moves, thereby sealing the pressure chamber.

[0007] The drive mechanism may further include a guide bush that is supported within the casing and that supports the drive member movably in the movement direction.

[0008] The driving member may have a piston, and the sealing member may have a plurality of sealing members, some of which are provided on an upper surface side of the piston, and the remaining sealing members may be provided on a lower surface side of the piston.

[0009] A valve according to one aspect of the present invention includes a body having a flow path formed therein, and the above-described actuator attached to the body and capable of opening and closing the flow path. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide an actuator and a valve that can be used for a long period of time, even when used in a high-temperature environment, by suppressing deterioration in the sealing performance of the O-ring. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a partial cross-sectional view of the valve in a closed state according to the first embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the actuator of the valve in an open state according to the first embodiment. [Figure 3] FIG. 10 is a cross-sectional view of the actuator of the valve in the closed state according to the second embodiment. [Figure 4]FIG. 10 is a cross-sectional view of the actuator of the valve in an open state according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] An actuator and a valve according to a first embodiment of the present disclosure will be described with reference to the drawings. 1 shows a cross-sectional view of a valve 1 in a closed state according to a first embodiment. The valve 1 according to this embodiment is a diaphragm valve.

[0013] The valve 1 includes a body 10 and an actuator 20. Although the type of valve is not limited, the valve 1 according to this embodiment is a so-called three-way valve. In the following description, the actuator 20 side of the valve 1 is referred to as the upper side, and the body 10 side is referred to as the lower side.

[0014] [Body part 10] The body portion 10 includes a body 11 , a seat 12 which is a valve seat, a bonnet 13 , a diaphragm 14 , a pressure adapter 15 , and a diaphragm pressure member 16 .

[0015] The body 11 is generally cubic. The body 11 includes a valve chamber 11a, a first inlet passage 11b, a second inlet passage 11c, an outlet passage 11d, and an annular groove 11e. The first inlet passage 11b branches into two passages (not shown) that communicate with the annular groove 11e. The resin sheet 12 is annular and is provided on the body around the periphery of the portion where the second inlet passage 11c communicates with the annular groove 11e.

[0016] The bonnet 13 is a generally cylindrical lidded valve, and its lower end is screwed onto the body 11 to secure it to the body 11 so as to cover the valve chamber 11a. The diaphragm 14, which serves as the valve element, is held in place by clamping its outer periphery between a presser adapter 15 located at the lower end of the bonnet 13 and the bottom surface of the body 11 that forms the valve chamber 11a. The diaphragm 14 moves away from and comes into contact with (pressure-contact with) the seat 12, thereby opening and closing the fluid passage.

[0017] Diaphragm retainer 16 is provided above diaphragm 14 and is configured to be able to press against the center of diaphragm 14. Diaphragm retainer 16 is fitted into holder 24A, which will be described later. Compression coil spring 24B, which will be described later, presses diaphragm retainer 16 via holder 24A, and valve 1 is kept in a closed state under normal conditions (when actuator 20 is not operating).

[0018] [Actuator 20] The actuator 20 is air-driven, has a generally cylindrical shape overall, and includes a lower casing 21, an upper casing 22, a first guide bush 23A, a second guide bush 23B, a stem 24, a holder 24A, a compression coil spring 24B, a piston 25, a pressing member 26, an air port portion 27, and first to fifth O-rings 28A to 28E.

[0019] The lower casing 21 is generally stepped and cylindrical, and includes a lower portion 21A, an intermediate portion 21B, and an upper portion 21C. The outer periphery of the lower end of the lower portion 21A is threadedly engaged with the inner periphery of a through-hole at the upper end of the bonnet 13. A first through-hole 21d is formed in the center of the lower portion 21A and the intermediate portion 21B. The lower portion of the first through-hole 21d has a larger diameter than the upper portion. A first stepped portion 21E is formed on the inner circumferential surface of the lower portion 21A. The upper end of the holder 24A is inserted into the first through-hole 21d. The holder 24A is supported by the lower portion 21A so as to be movable in the up and down direction. The intermediate portion 21B is generally disk-shaped and includes the first through-hole 21d. A first annular recess 21f is formed on the inner circumferential surface of the intermediate portion 21B. The upper portion 21C has an annular shape and is provided so as to protrude upward from the outer periphery of the middle portion 21B.

[0020] The upper casing 22 has a generally closed cylindrical shape and includes an outer tubular portion 22A and an upper lid portion 22B. The outer tubular portion 22A is screwed onto the upper side portion 21C, thereby fixing the upper casing 22 to the lower casing 21. The upper lid portion 22B is provided to cover the upper end of the outer tubular portion 22A. A second through-hole 22c is formed in the center of the upper lid portion 22B. The second through-hole 22c is countersunk, and the upper lid portion 22B has a second stepped portion 22D. A disk-shaped second recess 22f is formed in the lower surface 22E of the upper lid portion 22B so as to surround the second through-hole 22c. A leak port 22g is formed in the upper lid portion 22B. The leak port 22g opens to a portion of the lower surface 22E outside the second recess 22f and to the outer peripheral surface of the upper lid portion 22B.

[0021] The first guide bush 23A and the second guide bush 23B are cylindrical resin bearings. The first guide bush 23A is provided inside the upper portion 21C of the lower casing 21. The second guide bush 23B is provided in the first recess 21f. The axial directions of the first guide bush 23A and the second guide bush 23B coincide with the axial directions of the casings (the lower casing 21 and the upper casing 22) and the bonnet 13.

[0022] The stem 24 is provided in the first through-hole 21d and supported by the second guide bush 23B so as to be vertically movable. The stem 24 moves toward and away from the diaphragm 14 to open and close the first inlet passage 11b, the second inlet passage 11c, and the outlet passage 11d. The lower portion of the stem 24 is threadedly engaged with a recess in the upper portion of the holder 24A. The holder 24A is generally cylindrical and is disposed within the bonnet 13 so as to be vertically movable. The compression coil spring 24B is provided within the bonnet 13 and constantly biases the holder 24A downward.

[0023] The piston 25 is integral with the stem 24 and is provided above the stem 24. The piston 25 has a base 25A, a first protruding portion 25B, a second protruding portion 25C, and a third protruding portion 25D. The base 25A is generally disk-shaped, and the stem 24 is provided integrally on its underside. The base 25A is supported by a first guide bush 23A so as to be movable in the vertical direction. The stem 24, the piston 25, and the holder 24A together constitute a driving member.

[0024] The first protrusion 25B is generally disk-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 generally disk-shaped and protrudes upward from the upper surface of the first protrusion 25B. The third protrusion 25D is generally 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 defined by the lower surface of the base portion 25A and the upper surface of the middle portion 21B of the lower casing 21. A working fluid introduction passage 25f extending from the upper end of the piston 25 to the pressure chamber 25e is formed in the piston 25. The working fluid introduction passage 25f penetrates the base portion 25A, the first protruding portion 25B, the second protruding portion 25C, and the third protruding portion 25D, and branches into multiple passages at the base portion 25A.

[0026] The pressing member 26 is generally cylindrical and has a third through-hole 26a in its center. A protrusion 26B protruding inward into the third through-hole 26a is provided at the upper end of the pressing member 26. The protrusion 26B has a smaller inner diameter than the remaining portion of the third through-hole 26a. The third protrusion 25D is inserted into the lower portion of the protrusion 26B in the third through-hole 26a. The upper end of the third protrusion 25D is threadedly engaged with 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 portion 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 step portion 22D.

[0027] The airport portion 27 has a generally stepped cylindrical shape and is fixed to the upper surface of the top cover portion 22B. A fourth through-hole 27a is formed in the center of the airport portion 27. The lower portion of the fourth through-hole 27a has a larger diameter than the 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 top cover portion 22B and the airport portion 27 so as to be movable in the vertical direction. The fourth through-hole 27a communicates with the working fluid introduction passage 25f via the third through-hole 26a. A working fluid supply source (not shown) is connected to the airport portion 27 via a pipe fitting and a metal pipe (not shown).

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

[0029] Fourth O-ring 28D is provided around stem 24 in pressure chamber 25e. When valve 1 is closed, fourth O-ring 28D is compressed between the lower surface of base portion 25A and the upper surface of middle portion 21B, sealing pressure chamber 25e. Fifth O-ring 28E is provided around stem 24, between the upper end of holder 24A and first stepped portion 21E. When valve 1 is fully open, fifth O-ring 28E is compressed between the upper end of holder 24A and the lower surface of first stepped portion 21E, sealing pressure chamber 25e.

[0030] The first to fifth O-rings 28A to 28E are provided in the casing so that they abut against either the casing (lower casing 21 and upper casing 22) or the piston 25 in a direction perpendicular to the movement direction (up and down direction) of the piston 25, or they abut against neither. That is, the first to fifth O-rings 28A to 28E are not pressed by both the casing and the piston 25 in a direction perpendicular to the movement direction (up and down direction) of the piston 25. In a crushed state, the first to fifth O-rings 28A to 28E abut against either the casing or the piston 25, or they abut against neither. The first to fifth O-rings 28A to 28E correspond to sealing members.

[0031] Next, the opening and closing operation of the valve 1 according to this embodiment will be described. FIG. 2 shows a partial cross-sectional view of the actuator 20 of the valve 1 in an open state.

[0032] 1, in the closed state of valve 1, no working fluid flows into pressure chamber 25e, stem 24 and piston 25 are at bottom dead center (close to body 11) due to the biasing force of compression coil spring 24B, and diaphragm 14 is pressed by diaphragm retainer 16, closing valve 1. In other words, valve 1 is closed in its normal state (when no driving fluid is supplied). In the closed state of valve 1, first inlet channel 11b and outlet channel 11d communicate with each other via annular groove 11e.

[0033] A state in which working fluid flows from a working fluid supply source (not shown) to valve 1 is established. This supplies a driving fluid to valve 1. The driving fluid passes through metal piping and a pipe fitting (not shown), through fourth through-hole 27a, third through-hole 26a, and working fluid introduction passage 25f, and then flows into pressure chamber 25e. As a result, as shown in FIG. 2, piston 25 rises against the biasing force of compression coil spring 24B. As a result, holder 24A and stem 24 move to the top dead center (separated from body 11), and diaphragm retainer 16 moves upward due to the elastic force of diaphragm 14 and the pressure of the fluid (gas). Second inlet passage 11c and outlet passage 11d communicate with each other via annular groove 11e, and valve 1 enters the open state.

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

[0035] To change valve 1 from an open state to a closed state, a three-way valve (not shown) is switched to a flow that discharges the working fluid from actuator 20 (pressure chamber 25e) of valve 1 to the outside. This causes the working fluid in pressure chamber 25e to be discharged to the outside via working fluid inlet path 25f. As a result, stem 24 and piston 25 move to bottom dead center by the biasing force of compression coil spring 24B, and valve 1 enters the closed state (FIG. 1).

[0036] According to the actuator 20 described above, the first to fifth O-rings 28A to 28E are disposed within the casing so that they abut either the casing (the lower casing 21 and the upper casing 22) or the drive member (the stem 24, the piston 25, and the holder 24A) in a direction perpendicular to the movement direction of the drive member, or so that they abut neither. As the drive member moves, they are crushed by the drive member and the casing in the movement direction, sealing the pressure chamber 25e. In this way, the first to fifth O-rings 28A to 28E do not slide against other components such as the casing, but are simply crushed. As a result, even when used for a long period of time in a high-temperature environment, wear of the first to fifth O-rings 28A to 28E due to sliding can be suppressed, and deterioration of the sealing performance of the first to fifth O-rings 28A to 28E can be suppressed. This prevents leakage of the working fluid from the pressure chamber 25e. This ultimately extends the life of a valve used in a high-temperature environment.

[0037] The drive member is supported by first guide bush 23A and second guide bush 23B so as to be movable in the movement direction, allowing the axis of the casing and the axis of the drive member to be aligned. First to third O-rings 28A to 28C are provided on the upper surface of piston 25, and fourth and fifth O-rings 28D to 28E are provided on the lower surface of piston 25. This prevents leakage of working fluid from pressure chamber 25e to the outside when valve 1 is between fully closed and fully open. This in turn extends the life of the valve used in high-temperature environments.

[0038] Next, an actuator and a valve according to a second embodiment of the present disclosure will be described with reference to the drawings. Figure 3 is a cross-sectional view of actuator 120 of valve 101 in a closed state according to the second embodiment. Figure 4 is a cross-sectional view of actuator 120 of valve 101 in an open state according to the second embodiment. The same reference numerals are used for the same members as those in actuator 20 of the first embodiment, and descriptions thereof will be omitted.

[0039] The actuator 120 of this embodiment does not have the pressing member 26 of the first embodiment, and the airport 127 is threadedly engaged with the third protrusion 25D of the piston 125. The second through-hole 122c formed in the upper cover 122B of the upper casing 122 is cylindrical rather than countersunk. The piston 125 does not have the second protrusion 25C of the first embodiment, and the third protrusion 25D is provided on the first protrusion 25B. The airport 127 is generally cylindrical with a step, and the third protrusion 25D is inserted into the expanded portion of the fourth through-hole 127a. The upper end of the third protrusion 25D is threadedly engaged with the fourth through-hole 127a, and the airport 127 is fixed to the piston 125. Therefore, the airport 127 moves up and down together with the piston 125. The upper end of the third protrusion 25D abuts against the third step 127B. The lower portion of the air port portion 127 is inserted into the second through-hole 122c.

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

[0041] The actuator 120 of this embodiment can also achieve the same effects as the actuator 20 of the first embodiment. Furthermore, the actuator 120 can reduce the number of O-rings.

[0042] The present disclosure is not limited to the above-described embodiments, and those skilled in the art may make various additions and modifications within the scope of the present disclosure.

[0043] For example, in the above embodiment, the drive member is supported by the first guide bush 23A and the second guide bush 23B. However, instead of providing the first guide bush 23A and the second guide bush 23B, the inner circumferential surface of the casing may be coated with a paint or the like with excellent sliding properties, and the drive member may be supported by the inner circumferential surface so as to be movable up and down. While two guide bushes, the first guide bush 23A and the second guide bush 23B, may be provided, only one of them may be used. A recess may be provided on the upper surface of the middle portion 21B of the lower casing 21, and a fourth O-ring 28D may be placed therein. [Explanation of symbols]

[0044] 1, 101: valve, 11: body, 11b: first inlet passage, 11c: second inlet passage, 11d: outlet passage, 11e: annular groove, 20, 120: actuator, 21: lower casing, 22, 122: upper casing, 23A: first guide bush, 23B: second guide bush, 24: stem, 24A: holder, 25, 125: piston, 25e: pressure chamber, 28A to 28E: first to fifth O-rings

Claims

1. A casing; a driving member provided within the casing to form a pressure chamber together with the casing and driven by an external working fluid; an annular sealing member provided within the casing so as to abut either one of the casing and the driving member in a direction perpendicular to the direction of movement of the driving member, or so as not to abut either of them, and which is crushed in the direction of movement by the driving member and the casing as the driving member moves, thereby sealing the pressure chamber.

2. 2. The actuator according to claim 1, further comprising a guide bush supported within the casing and supporting the drive member movably in the movement direction.

3. The drive member has a piston; 3. The actuator according to claim 1, wherein the seal member includes a plurality of seal members, some of which are provided on an upper surface side of the piston, and the remaining of which are provided on a lower surface side of the piston.

4. a body having a flow path formed therein; A valve comprising: the actuator according to claim 1 , attached to the body and capable of opening and closing the flow path.

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