JP7348628B2 - Actuator and air operated valve equipped with it - Google Patents

Description

The present invention relates to an actuator and an air operated valve equipped with the same.

Patent Document 1 discloses a flow control valve that includes an actuator that opens and closes a valve body by raising and lowering a stem by supplying or cutting off a working fluid. This valve is an air-operated valve, and the actuator includes a housing in which a stem is supported so as to be movable up and down, a pressure chamber defined within the housing and supplied with working fluid, and an actuator housed in the housing so as to be movable up and down together with the stem. It has a piston.

The piston has a sliding outer circumferential surface that slides on the inner wall of the housing as the stem moves up and down, a pressure receiving surface that partitions a pressure chamber with the inner wall of the housing and receives the pressure of the working fluid, and an O-ring etc. on the outer circumferential surface of the stem. It is formed to have an inner circumferential surface fixed via an elastic member, and an annular fitting groove formed on the inner circumferential surface into which the elastic member is inserted.

In Patent Document 1, the piston is connected to a stem (corresponding to the rod in Patent Document 1) via an elastic member, thereby preventing the piston from tilting with respect to the stem.

Japanese Patent Application Publication No. 2014-109314

When the piston is tightly connected to the stem, it is conceivable to press-fit and fix the piston to the stem when assembling the valve. In this case, the fit between the inner circumferential surface of the piston and the outer circumferential surface of the stem is close to an interference fit, but a gap may occur between these surfaces. Therefore, in order to ensure the sealing function of the pressure chamber, it is necessary to connect the piston to the stem via an elastic member.

However, if the piston is press-fitted into the stem with the elastic member fitted into the fitting groove formed on the inner circumferential surface of the piston, the surface of the elastic member may come into contact with the outer circumferential surface of the stem and be damaged, or the stem may be damaged. The elastic member may be caught between the piston and the piston, and the elastic member may be torn. Furthermore, after the stem is press-fitted into the piston, the elastic member is fitted into the fitting groove and covered by the inner circumferential surface of the piston, so damage, entanglement, or tearing of the elastic member cannot be visually confirmed.

For this reason, even if the valve has no external problems, the sealing function of the pressure chamber may deteriorate due to damage, entrainment, or tearing of the elastic member when the piston is press-fitted, resulting in leakage of working fluid from the compression chamber. This may lead to malfunction of the valve. Therefore, there is a need to achieve both an alignment function that prevents the piston from tilting with respect to the stem and a pressure chamber sealing function by connecting the piston to the stem by a method other than press fitting.

The present invention has been made in view of these problems, and its objectives are to provide an alignment function that prevents the piston from tilting with respect to the stem by connecting the piston to the stem by a method other than press fitting; An object of the present invention is to provide an actuator that can achieve both the function of sealing a pressure chamber and an air-operated valve equipped with the actuator.

The present invention can be realized as the following aspects.
The actuator according to this aspect is an actuator that raises and lowers a stem by supplying or blocking a working fluid, and includes a housing in which the stem is supported so as to be movable up and down, and a pressure chamber partitioned within the housing and supplied with the working fluid. The housing includes a piston that is housed in a housing so as to be movable up and down together with the stem, and a connecting mechanism that connects the stem and the piston. a connecting member having an engaging portion for the piston, a fixing member for fixing the connecting member to the piston, and an engaged portion formed on the stem and to which the engaging portion is engaged , the engaged portion being The engaging part is formed by cutting out annularly from the inner circumferential surface of the connecting member to the opposing surface of the connecting member facing the piston, into which the flange is fitted. This is the first counterbore .

Further , in the above-described actuator according to this aspect, the depth of the first counterbore portion is equal to or less than the thickness of the collar portion in the axial direction of the stem.

Further, in the above-described actuator according to this aspect, the mutual contact surfaces of the collar portion and the first counterbore portion in the radial direction of the stem are tapered surfaces that expand in diameter from the stem and are inclined in a direction approaching the piston. .
Further, in the above-described actuator according to this aspect, the coupling mechanism includes a flange portion having an enlarged diameter on the outer circumferential surface of the stem, and a fixing member that fixes the flange portion to the piston.

Further, in the above-described actuator according to this aspect, the piston has a sliding outer circumferential surface that slides on the inner wall of the body of the housing as the stem moves up and down, and a pressure chamber that partitions the pressure chamber with the inner wall and receives the pressure of the working fluid. 1 pressure-receiving surface, an insertion surface portion inserted into the stem, and a first insertion portion continuous with the insertion surface portion and formed by cutting out across the first pressure-receiving surface, into which the annular first elastic member is fitted. It has a peripheral surface.

Further, in the above-described actuator according to this aspect, the stem has a flow path for working fluid that opens into the pressure chamber, and the actuator is fixed to the inner wall and defines the pressure chamber together with the first pressure receiving surface and the inner wall. The partitioning member has a sliding inner circumferential surface on which the outer circumferential surface of the stem slides via the second elastic member as the stem moves up and down, and the pressure chamber is partitioned together with the inner wall and the first pressure receiving surface. , has a second pressure-receiving surface that receives the pressure of the working fluid, and a second fitting portion that is formed by cutting out from the sliding inner circumferential surface to the second pressure-receiving surface and into which the second elastic member is fitted.

Further, in the above-described actuator according to this aspect, at least one of the first and second pressure receiving surfaces is connected to the flow path when the first pressure receiving surface contacts the second pressure receiving surface as the stem descends. It has a second counterbore.
Furthermore, in the above-described actuator according to this aspect, the first and second elastic members are exposed to the second counterbore portion when the first pressure receiving surface contacts the second pressure receiving surface as the stem descends.

Furthermore, the above-described actuator according to the present embodiment each includes a plurality of pressure chambers and a plurality of pistons facing the pressure chambers.
Furthermore, in the above-described actuator according to this aspect, the stem has an opening/closing detection sensor that opens and closes the valve body by moving up and down, and detects the opening and closing of the valve body as the piston moves up and down, based on a change in the distance to the piston.

On the other hand, the air operated valve according to this aspect includes any of the actuators described above.

According to the actuator of the present invention and the air-operated valve equipped with the same, by connecting the piston to the stem by a method other than press fitting, it has an alignment function that prevents the piston from tilting with respect to the stem, and a pressure chamber sealing function. Both can be achieved.

FIG. 1 is a longitudinal cross-sectional view of an air-operated valve equipped with an actuator according to an embodiment of the present invention when the valve is open. FIG. 2 is an enlarged view of the actuator of FIG. 1; FIG. 3 is a plan view of the coupling mechanism as seen from the arrow AA in FIG. 2; FIG. 2 is a longitudinal cross-sectional view of the air operated valve of FIG. 1 when the valve is closed. FIG. 4 is an enlarged view of the actuator of FIG. 3; It is a longitudinal cross-sectional view of the connection mechanism concerning the modification of the present invention.

Hereinafter, one embodiment of the present invention will be described based on the drawings. FIG. 1 shows a vertical cross-sectional view of an air operated valve 1 (hereinafter also simply referred to as valve 1) equipped with an actuator 18 according to an embodiment of the present invention when the valve is open. Note that in the following description of FIGS. 1, 2, and 4 to 6, the upper side of each figure is referred to as the upper side.

The valve 1 is a direct touch metal diaphragm valve that can control the minute flow rate of process fluid with high precision, and includes a body 2, a diaphragm 4, a bonnet 6, a bonnet nut 8, a diaphragm retainer 10, a retainer adapter 12, a stem 14, and a spring. 16, an actuator 18, etc. The valve 1 is used, for example, in a semiconductor manufacturing device using a film forming technique such as ALD (Atomic Layer Deposition).

The body 2 is made of a metal material such as stainless steel, and a fluid inlet 20 and a fluid outlet 22 are formed in the lower part of the body 2. A valve chamber 24 with a concave cross section and open upward is formed in the upper part of the body 2 and communicates with a fluid inlet 20 and a fluid outlet 22 . A valve seat 26 made of synthetic resin is provided on the bottom surface of the valve chamber 24, and an annular step portion 28 is formed on the lower side of the inner peripheral surface of the valve chamber 24.

The cylindrical lower end of the bonnet 6 is inserted into the valve chamber 24 of the body 2, and is screwed into the cylindrical upper part of the body 2. A stem 14 is disposed within the bonnet 6 so as to be movable up and down, and a coil-shaped spring 16 is disposed around the stem 14. The spring 16 urges the enlarged diameter portion 14a formed at the bottom of the stem 14 downward. A diaphragm presser 10 made of synthetic resin that can come into contact with the upper surface of the central portion of the diaphragm 4 is fitted onto the lower surface of the enlarged diameter portion 14a.

A rod 30 is screwed and connected to the upper part of the stem 14. The rod 30 protrudes from the top of the bonnet 6 and is inserted into the actuator 18. Note that since the rod 30 is connected to the stem 14 and moves up and down together, the rod 30 may be treated as the same as the stem 14. The diaphragm 4 is arranged above the valve seat 26 and is composed of a plurality of diaphragms. Further, the diaphragm 4 has a dish shape in its natural state with a central portion curved upward.

The diaphragm 4 has an extremely thin thickness and is made of a metal material such as stainless steel or other shape memory alloy. The retainer adapter 12 is an annular member attached to the inner peripheral surface of the valve chamber 24 and is pressed toward the stepped portion 28 by the cylindrical lower end of the bonnet 6 . The peripheral edge of the diaphragm 4 is clamped and fixed by the stepped portion 28 and the presser adapter 12, and the airtightness of the valve chamber 24 is maintained.

The actuator 18 of this embodiment moves the stem 14 up and down by supplying or cutting off working fluid from a fluid supply source (not shown), and places the diaphragm 4, which is a valve body, on and off the valve seat 26, thereby opening and closing the valve 1. This is a fluid-operated drive mechanism that performs The actuator 18 includes a housing 34 , two pressure chambers 36 partitioned into upper and lower sections in the housing 34 , two pistons 38 arranged above and below in the housing 34 facing the individual pressure chambers 36 , and each piston 38 in the housing 34 . One partition member 40 is provided between the pistons 38.

The actuator 18 includes an opening/closing detection sensor 42 at a position facing the upper piston 38. The opening/closing detection sensor 42 is, for example, an optical sensor, and is inserted from the top surface of the actuator cap 34a, and uses the top surface of the upper piston 38 as a reflecting surface. The opening/closing detection sensor 42 detects the opening/closing of the diaphragm 4 as the stem 14 moves up and down, that is, the opening/closing operation of the valve 1 based on a change in the distance to the upper piston 38. The actuator 18 is equipped with a stroke adjustment mechanism that can adjust the amount of stroke caused by raising and lowering the stem 14.

FIG. 2 shows an enlarged view of the actuator 18 of FIG. The housing 34 is formed by coupling an upper actuator cap 34a and a lower actuator body 34b by screwing or the like. An opening 34d into which the rod 30 is inserted is formed in the cylindrical lower portion 34c of the actuator body 34b. The actuator 18 is fastened and fixed to the bonnet 6 by inserting the cylindrical lower part 34c into the bonnet 6 and tightening the bonnet nut 8. The rod 30 is supported by the housing 34 via an upper O-ring 35 and a lower O-ring (second elastic member) 37 so as to be movable up and down.

A working fluid supply port 44 to which a fluid supply source is connected is formed at the top of the actuator cap 34a, and the supply port 44 communicates with a working fluid flow path 46 opened at the upper end of the rod 30. The flow path 46 includes an axial hole 46a that extends in the axial direction of the rod 30, and two systems of radial holes 46b that branch out from the axial hole 46a in the radial direction. Working fluid is supplied to the two pressure chambers 36 from the supply port 44 through the axial hole 46a and the radial hole 46b in this order.

The two pistons 38 are connected to the rod 30 and housed in the housing 34 so as to be movable up and down together with the rod 30. Specifically, as shown in FIG. 2, each piston 38 has a sliding outer peripheral surface 38a, a first pressure receiving surface 38b, and an inner peripheral surface 38c. The sliding outer circumferential surface 38a slides on the inner wall 34e of the housing 34 via an O-ring 47 as the stem 14 moves up and down. The first pressure receiving surface 38b has an annular shape, partitions the pressure chamber 36 together with the inner wall 34e, and receives the pressure of the working fluid.

In the case of the lower piston 38, the pressure chamber 36 is defined by the first pressure receiving surface 38b, the inner wall 34e, and the bottom wall (dividing member) 34f of the housing 34, which is a part of the inner wall 34e. The inner circumferential surface 38c is fixed to the outer circumferential surface 30a of the rod 30 via a first O-ring (first elastic member) 48, not by an interference fit such as a press fit, but by an intermediate fit. . A first fitting portion 52 is formed on the inner circumferential surface 38c.

Here, the actuator 18 of this embodiment includes a connection mechanism 70 that connects the stem 14 and the upper piston 38. The connecting mechanism 70 includes a connecting member 72 that connects the stem 14 and the piston 38, a screw (fixing member) 74 that secures the connecting member 72 to the piston 38, and a flange (an engaged portion) formed on the stem 14. 76.

The connecting member 72 has a disk shape and is positioned in a space 38g of the actuator cap 34a between the bottom surface 38f of the actuator cap 34a from which the opening/closing detection sensor 42 projects and the top surface 38d of the upper piston 38. When inserted into the stem 14, the connecting member 72 has an inner circumferential surface 72a that faces or comes into contact with the outer circumferential surface 30a of the rod 30, in other words, the outer circumferential surface 14b of the stem 14, and an inner circumferential surface 72a that engages with the flange 76. It has a first counterbore portion (engaging portion) 78 that is fitted.

The collar portion 76 is formed by expanding the diameter of the outer circumferential surface 14b of the stem 14, and the lower surface 76a of the collar portion 76 is in contact with the upper surface 38d of the upper piston 38. Thereby, when the working fluid is supplied to the pressure chambers 36, the stem 14 is pushed up together with the piston 38 by the pressure in each pressure chamber 36, and rises. The connecting member 72 has a thickness that does not contact the bottom surface 38f of the actuator cap 34a even if it moves up and down in accordance with the stroke of the stem 14 in the space 38g, and has an outer diameter that does not contact the opening/closing detection sensor 42.

The first counterbore portion 78 is formed by cutting out annularly from the inner circumferential surface 72a of the connecting member 72 to the lower surface (opposing surface) 72b of the connecting member 72 facing the piston 38, and the collar portion 76 is fitted into the first counterbore portion 78. The depth D of the first counterbore portion 78 is set to be equal to or less than the thickness W of the collar portion 76 in the axial direction of the stem 14 .

Thereby, when the connecting member 72 is fastened with the screw 74, the connecting member 72 does not bend. Further, when the depth D is equal to the thickness W, the bottom surface 78a of the first counterbore portion 78 and the upper surface 76b of the flange portion 76 are in contact with each other, and the lower surface 76a of the flange portion 76 is brought into contact with the upper surface of the piston 38 by the fastening force of the screw 74. 38d.

FIG. 3 shows a plan view of the coupling mechanism 70 as seen from the direction arrow AA in FIG. The connecting member 72 has a circular shape in plan view and is fastened to the upper surface 38d of the piston 38 with four screws 74. In this way, by providing the actuator 18 with the coupling mechanism 70, the pistons 38 are tightly coupled to the stem 14 by a method other than press fitting, and an alignment function that prevents each piston 38 from tilting with respect to the stem 14 can be realized. can. Further, the first fitting portion 52 is formed by cutting out the corner portion extending from the inner circumferential surface 38c to the first pressure receiving surface 38b over the entire circumference.

When assembling the valve 1, the first O-ring 48 is fitted into the first fitting portion 52 either before or after the piston 38 is connected to the stem 14 by the connection mechanism 70. Since the piston 38 is not press-fitted into the stem 14, damage, entanglement, and tearing of the first O-ring 48 can be reliably prevented, and the sealing function of each pressure chamber 36 can be realized.

Further, the condition of the first O-ring 48 can be easily visually confirmed from the first fitting portion 52. Therefore, even in the unlikely event that the first O-ring 48 is damaged, entangled, or torn, these conditions can be detected at an early stage. Further, the first O-ring 48 is fitted into the first fitting part 52 with friction while applying its own elastic force due to crushing and deformation to the inner wall of the first fitting part 52. Therefore, the first O-ring 48 does not fall off even when the piston 38 moves up and down.

Furthermore, since the first O-ring 48 is exposed to the pressure chamber 36, when the valve 1 is fully opened, the first O-ring 48 is pressed against the inner wall of the first fitting part 52 by the pressure of the working fluid acting on the pressure chamber 36. . This pressing force further promotes the crushing deformation of the first O-ring 48 within the first fitting portion 52, and further improves the sealing performance of each pressure chamber 36.

Further, the first O-ring 48 is exposed to the pressure chamber 36 and comes into contact with the working fluid, and may undergo thermal expansion depending on the temperature assumed by the working fluid. If such thermal expansion of the first O-ring 48 occurs in the conventional fitting groove with a limited space, the thermal expansion is restricted and there is no place for the heat to escape, so the first O-ring 48 hardens, softens, and swells. This may cause deterioration such as

However, in the case of the present embodiment, the first O-ring 48 is fitted into the first fitting portion 52, so that the degree of freedom of thermal expansion is guaranteed to a certain extent, and a heat escape path is secured to a certain extent. Therefore, the deterioration of the first O-ring 48 due to the thermal expansion and the influence on the sealing performance of the pressure chamber 36 are reduced.

On the other hand, the partitioning member 40 is fixed to the inner wall 34e between the two pistons 38, and partitions the upper pressure chamber 36 together with the first pressure receiving surface 38b of the upper piston 38 and the inner wall 34e. Specifically, the partition member 40 has a sliding inner peripheral surface 40a, a second pressure receiving surface 40b, and a fixed outer peripheral surface 40c. The sliding inner circumferential surface 40a slides on the outer circumferential surface 30a of the rod 30 via a second O-ring (second elastic member) 54 as the stem 14 moves up and down.

The second pressure receiving surface 40b has an annular shape, partitions the pressure chamber 36 together with the inner wall 34e and the first pressure receiving surface 38b, and receives the pressure of the working fluid. The fixed outer peripheral surface 40c is fixed to the inner wall 34e via an O-ring 56. A sliding surface portion 58 and a second fitting portion 60 are formed on the sliding inner peripheral surface 40a. The outer peripheral surface 30a of the rod 30 slides on the sliding surface portion 58 as the stem 14 moves up and down.

The second fitting portion 60 is formed by cutting out the corner portion extending from the sliding inner circumferential surface 40a to the second pressure receiving surface 40b over the entire circumference, and the second O-ring 54 is fitted into the second fitting portion 60. As a result, the rod 30 is slid against the partition member 40 in an airtight manner, and the sealing function of the upper pressure chamber 36 is ensured. Further, as in the case of the first O-ring 48, the second O-ring 54 is fitted into the second fitting portion 60 with friction due to its own elastic force due to crushing and deformation.

Therefore, the second O-ring 54 will not fall off even when the rod 30 is moved up and down. Furthermore, the second O-ring 54 is exposed to the pressure chamber 36, similar to the first O-ring 48. Therefore, when the valve 1 is fully opened, the second O-ring 54 is pressed against the inner wall of the second fitting portion 60 by the pressure of the working fluid acting on the pressure chamber 36 . This pressing force further promotes the crushing deformation of the second O-ring 54 within the second fitting portion 60, and further improves the sealing performance of the upper pressure chamber 36.

Furthermore, since the second O-ring 54 is fitted into the second fitting portion 60, thermal expansion is allowed to some extent, similarly to the case of the first O-ring 48. Therefore, the adverse effects caused by the thermal expansion of the second O-ring 54 in a limited space as in the conventional case, that is, the deterioration of the second O-ring 54 and the influence on the sealing performance of the lower pressure chamber 36, are reduced. Ru.

Further, the bottom wall 34f of the housing 34 has the same function as the partitioning member 40 in the sense of partitioning the lower pressure chamber 36, and the lower O-ring 37 has a lower fitting portion provided on the bottom wall 34f. (Second fitting part) 39 is fitted into the pressure chamber 36 so as to be exposed, and has the same function as the second O-ring 54. Therefore, the sealing function of the lower pressure chamber 36 is also ensured. Furthermore, the first pressure receiving surface 38b has a second counterbore portion 62 with which the radial hole 46b of the flow path 46 is communicated when the first pressure receiving surface 38b contacts the second pressure receiving surface 40b as the stem 14 descends. is formed.

Hereinafter, the opening/closing operation of the valve 1 and the function of the second counterbore portion 62 will be explained.
FIG. 4 shows a longitudinal sectional view of the valve 1 when the valve is closed, and FIG. 5 shows an enlarged view of the actuator 18 in FIG. 4. In the case of FIGS. 4 and 5, the stem 14 is urged downward by the elastic force of a spring 16 provided within the bonnet 6.

When the valve 1 changes from the closed state shown in FIGS. 4 and 5 to the open state shown in FIGS. 1 and 2, working fluid is supplied from the supply port 44 to the two pressure chambers 36 via the flow path 46. The pressure in each pressure chamber 36 causes the piston 38 and the stem 14 to rise against the elastic force of the spring 16. As a result, the diaphragm 4 assumes a natural state with a convex cross section due to its own restoring force and is separated from the valve seat 26, and the valve 1 becomes fully open.

On the other hand, when the valve 1 changes from the valve open state shown in FIGS. 1 and 2 to the valve closed state shown in FIGS. 4 and 5, the supply of working fluid from the supply port 44 is stopped, and the flow paths 46 and 2 The pressure in the two pressure chambers 36 is released. In this state, the piston 38 and stem 14 are lowered by the elastic force of the spring 16. As a result, the center portion of the diaphragm 4 is pressed downward by the diaphragm retainer 10, and is deformed into a concave cross-section against its own restoring force and rests on the valve seat 26, and the valve 1 becomes fully closed.

Here, if the stroke amount of the stem 14 is reduced by the stroke adjustment mechanism, the first pressure receiving surface 38b may come into contact with the second pressure receiving surface 40b as the stem 14 descends. If the first and second pressure receiving surfaces 38b and 40b come into contact with each other, the necessary volume cannot be secured in the pressure chamber 36, and the radial hole 46b will be blocked, resulting in malfunction of the valve 1. obtain. There is also a risk that the first O-ring 48 may come into contact with the partitioning member 40 and be damaged.

However, by forming the second counterbore portion 62 on the first pressure receiving surface 38b, even if the first pressure receiving surface 38b contacts the second pressure receiving surface 40b as shown in FIG. Since the radial hole 46b is opened, working gas can be supplied to the space. Therefore, the space of the second counterbore portion 62 is secured as the pressure chamber 36.

Further, in order to avoid contact between the first and second pressure receiving surfaces 38b and 40b, it is not necessary to ensure a large pressure chamber 36 when the valve 1 is fully closed, taking into account a safety factor, and the outer shape of the actuator 18 is It is not necessary to secure it long in the axial direction. Therefore, while ensuring the reliability of the actuator 18 and thus the valve 1, it is possible to further reduce the size of the actuator 18 and thus the valve 1.

Further, after adjusting the stroke amount of the stem 14 to a small value using the stroke adjustment mechanism, it is also possible to further set the volume of the pressure chamber 36 to be as small as possible taking into consideration the space volume of the second counterbore portion 62. Thereby, the volume of the pressure chamber 36 can be set as small as possible, so that the responsiveness and controllability of the opening/closing operation of the valve 1 are improved. Further, as shown in FIG. 5, the first and second O-rings 48, 54 and the lower O-ring 37 are connected to each other when the first pressure-receiving surface 38b contacts the second pressure-receiving surface 40b as the stem 14 descends. 2 is exposed at the counterbore portion 62.

As a result, when working fluid is supplied to the pressure chamber 36 when the valve 1 shifts from a fully closed state to a fully open state, the first and second O-rings 48 and 54 are filled with working fluid in the space of the second counterbore portion 62. It is pressed, crushed and deformed. Therefore, even if the first and second pressure receiving surfaces 38b and 40b are in contact with each other, the sealing function of each pressure chamber 36 is ensured by forming the second counterbore portion 62.

As described above, the actuator 18 of the present embodiment and the valve 1 equipped with the actuator 18 achieve both the alignment function of preventing the piston 38 from tilting with respect to the rod 30, in other words, the stem 14, and the sealing function of the pressure chamber 36. can do. Particularly, when the valve 1 is used in a semiconductor manufacturing apparatus using a film forming technique of the ALD (Atomic Layer Deposition) method, the number of times the film is formed increases as the film thickness becomes extremely small.

For this reason, the number of opening and closing operations that the valve 1 can withstand (the number of times it can withstand) must be significantly increased. Therefore, it is conceivable to reduce the stroke amount of the stem 14 using a stroke adjustment mechanism to reduce the load caused by the bending displacement of the diaphragm 4 and increase the number of times the valve 1 can be used.

However, when the stroke amount of the stem 14 is reduced, the degree of influence of a minute inclination of the piston 38, which was conventionally allowed as an error range, increases. Therefore, if the opening/closing detection sensor 42 is placed in the valve 1 that requires opening/closing detection, there is a risk that the opening/closing detection sensor 42 will frequently erroneously detect the opening/closing operation of the valve 1 .

Therefore, in this embodiment, the actuator 18 is provided with a connecting mechanism 70 that connects the stem 14 and the upper piston 38. By providing the connecting mechanism 70, there is no need to press-fit and fix the piston 38 to the stem 14, which may occur when the piston 38 is press-fitted into the stem 14 while the piston 38 is tightly connected to the stem 14 by the connecting mechanism 70. Damage, entanglement, and tearing of the first O-ring 48 can be prevented.

Therefore, it is possible to realize both the alignment function of preventing each piston 38 from tilting with respect to the rod 30 and thus the stem 14, and the sealing function of each pressure chamber 36. Furthermore, by realizing these functions, when the opening/closing detection sensor 42 is disposed in the valve 1, it is possible to prevent false detection of the opening/closing operation of the valve 1, thereby improving the reliability of the valve 1. , it is also possible to improve the durability of the valve 1.

More specifically, the connecting mechanism 70 includes a connecting member 72 having a first counterbore 78 , a screw 74 , and a flange 76 formed on the stem 14 . As a result, the connection mechanism 70 can be easily configured by engaging the first counterbore portion 78 of the connection member 72 with the existing flange 76 formed on the stem 14 and fixing the connection member 72 to the piston 38 with the screws 74. can be realized.

Further, the depth D of the first counterbore portion 78 is set to be equal to or less than the thickness W of the collar portion 76 in the axial direction of the stem 14 . As a result, the stem 14, the piston 38, and the connecting member 72 can be reliably connected and integrated by abutting each other while preventing the connecting member 72 from bending, thereby reducing the inclination of each piston 38 with respect to the stem 14. It can be prevented more effectively.

Furthermore, as described above, since the first O-ring 48 is exposed to the pressure chambers 36, the sealing performance of each pressure chamber 36 is further improved. Further, deterioration of the first O-ring 48 due to thermal expansion of the first O-ring 48 and its influence on the sealing performance of the pressure chamber 36 are reduced. Furthermore, by forming the second fitting portion 60 in the form of a notch in the partitioning member 40, the rod 30 can be slid in an airtight manner against the partitioning member 40, and the sealing function of the upper pressure chamber 36 is ensured.

Moreover, the sealing function of the lower pressure chamber 36 is also ensured by the lower fitting part 39 formed on the bottom wall 34f of the housing 34 and the lower O-ring 37 fitted therein. Furthermore, since the second O-ring 54 and the lower O-ring 37 are exposed to the pressure chambers 36, the sealing performance of each pressure chamber 36 is further improved. Further, deterioration of the second O-ring 54 due to thermal expansion of the second O-ring 54 and its influence on the sealing performance of the pressure chamber 36 are reduced.

Further, by forming the second counterbore portion 62 on the first pressure receiving surface 38b, it is possible to secure the pressure chamber 36 even when the first pressure receiving surface 38b contacts the second pressure receiving surface 40b. Therefore, the valve 1 can be made smaller while ensuring its reliability, and the responsiveness and controllability of the opening/closing operation of the valve 1 are improved.

Further, the first and second O-rings 48, 54 and the lower O-ring 37 are connected to the second counterbore portion 62 even when the first pressure receiving surface 38b contacts the second pressure receiving surface 40b as the stem 14 descends. be exposed to. Thereby, even if the first and second pressure receiving surfaces 38b and 40b are in contact with each other, the sealing function of each pressure chamber 36 is ensured by forming the second counterbore portion 62.

This concludes the description of one embodiment of the present invention, but the present invention is not limited to this, and various changes can be made without departing from the spirit of the present invention. For example, in the embodiment described above, the engaging portion of the connecting member 72 with respect to the collar portion 76, which is the engaged portion of the stem 14, is the first counterbore portion 78. However, the present invention is not limited to this, and the engaging portion and the engaged portion may take various forms.

FIG. 6 shows a longitudinal sectional view of a coupling mechanism 70 according to a modification of the invention. The contact surfaces of the collar portion 76 and the first counterbore portion 78 with each other in the radial direction of the stem 14, that is, the upper surface 76b of the collar portion 76 and the bottom surface 78a of the first counterbore portion 78 are expanded in diameter from the stem 14, Moreover, it is formed as a tapered surface that is inclined in the direction approaching the piston 38. In this case, the upper side of the bottom surface 78a of the connecting member 72 is thinner than in the above-described embodiment.

Therefore, when the connecting member 72 is fastened with the screws 74, this thin portion is allowed to be slightly bent. As a result, even if a dimensional error occurs between the depth D of the first counterbore portion 78 and the thickness W of the stem 14 of the flange portion 76, due to the deflection, the bottom surface 78a of the first counterbore portion 78 and the flange portion The lower surface 76a of the flange 76 can be brought into reliable contact with the upper surface 38d of the piston 38 by the fastening force of the screw 74.

Therefore, the stem 14, the piston 38, and the connecting member 72 can be reliably connected and integrated by abutting each other without strict dimensional control when forming the connecting mechanism 70. It is possible to more effectively prevent each piston 38 from tilting with respect to the stem 14 while improving the stability.

Further, the connecting member 72 may be formed by dividing into a plurality of parts in the circumferential direction. For example, when the connecting member 72 is divided into four parts in the circumferential direction using four screws 74, the connecting member 72 can be fastened to the piston 38 while adjusting the torque of each divided member individually using the screws 74. Therefore, the alignment function of preventing the piston 38 from tilting with respect to the stem 14 can be performed more precisely.

Further, in the coupling mechanism 70, the diameter of the flange portion 76 may be further expanded on the outer circumferential surface 14b of the stem 14, and the flange portion 76 may be fixed to the piston 38 with screws 74. In this case, since the connecting member 72 is not required, the number of parts of the connecting mechanism 70 and thus the actuator 18 can be reduced, and the productivity of the actuator 18 is further improved.

Further, the second counterbore portion 62 is not limited to the above embodiment, and may be provided on at least one of the first and second pressure receiving surfaces 38b and 40b. Further, the actuator 18 is not limited to the above embodiment, and may include one piston 38 and one pressure chamber 36, or may include two or more paired pistons 38 and pressure chambers 36. Furthermore, the actuator 18 is not limited to the air-operated valve 1, but can also be applied to valves having other driving sources or to driven objects other than valves.

1 Air operated valve 4 Diaphragm (valve body)
14 Stem 14b outer peripheral surface 18 Actuator 30 Rod (stem)
30a Outer peripheral surface 34d Opening 34e Inner wall 34f Bottom wall (division member)
36 Pressure chamber 37 Lower O-ring (second elastic member)
38 Piston 38a Sliding outer peripheral surface 38b First pressure receiving surface 38c Inner peripheral surface 39 Lower fitting part (second fitting part)
40 Partitioning member 40a Sliding inner peripheral surface 40b Second pressure receiving surface 42 Opening/closing detection sensor 46 Flow path 48 First O-ring (first elastic member)
50 Press-fitting surface portion 52 First fitting portion 54 Second O-ring (second elastic member)
60 Second fitting part 62 Second counterbore part 70 Connection mechanism 72 Connection member 72a Inner peripheral surface 74 Screw (fixing member)
76 Flange part (engaged part)
76b Top surface (contact surface, tapered surface)
78 First counterbore part (engaging part)
78a Bottom surface (contact surface, tapered surface)

Claims (11)

An actuator that raises and lowers a stem by supplying or cutting off working fluid,
a housing in which the stem is supported so as to be movable up and down;
a pressure chamber defined within the housing and supplied with the working fluid;
a piston housed in the housing so as to be movable up and down together with the stem;
comprising a connection mechanism that connects the stem and the piston,
The connection mechanism is
a connecting member having an inner circumferential surface facing the outer circumferential surface of the stem, and having an engaging portion for the stem on the inner circumferential surface;
a fixing member fixing the connecting member to the piston;
an engaged portion formed on the stem and engaged with the engaging portion;
The engaged portion is a flange formed by expanding the diameter of the outer circumferential surface of the stem,
The engaging portion is a first counterbore portion formed by cutting out annularly from the inner circumferential surface of the connecting member to the opposing surface of the connecting member facing the piston, and into which the collar portion is fitted. actuator. The actuator according to claim 1 , wherein the depth of the first counterbore portion is equal to or less than the thickness of the collar portion in the axial direction of the stem. 2. A contact surface between the collar portion and the first counterbore portion in the radial direction of the stem is a tapered surface that increases in diameter from the stem and is inclined in a direction approaching the piston . Actuator described in. The connection mechanism is
a flange portion having an enlarged diameter on the outer circumferential surface of the stem;
The actuator according to claim 1, further comprising a fixing member that fixes the collar portion to the piston. The piston is
a sliding outer peripheral surface that slides on an inner wall of the body of the housing as the stem moves up and down;
a first pressure receiving surface that partitions the pressure chamber together with the inner wall and receives the pressure of the working fluid;
an inner circumferential surface consisting of an insertion surface portion to be inserted into the stem; and a first insertion portion that is continuous with the insertion surface portion and is cut out across the first pressure receiving surface and into which a first annular elastic member is fitted; The actuator according to any one of claims 1 to 4 , having the following. The stem has a flow path for the working fluid that opens into the pressure chamber,
The actuator has a partitioning member fixed to the inner wall and partitioning the pressure chamber together with the first pressure receiving surface and the inner wall,
The partition member is
a sliding inner peripheral surface on which the outer peripheral surface of the stem slides via a second elastic member as the stem moves up and down;
a second pressure receiving surface that partitions the pressure chamber together with the inner wall and the first pressure receiving surface and receives the pressure of the working fluid;
The actuator according to claim 5 , further comprising a second fitting part formed by cutting out from the sliding inner circumferential surface to the second pressure receiving surface, into which the second elastic member is fitted. At least one of the first and second pressure-receiving surfaces has a second counterbore portion through which the flow path is communicated when the first pressure-receiving surface contacts the second pressure-receiving surface as the stem descends. , The actuator according to claim 6 . The actuator according to claim 7 , wherein the first and second elastic members are exposed to the second counterbore when the first pressure-receiving surface contacts the second pressure-receiving surface as the stem descends. The actuator according to any one of claims 1 to 8 , comprising a plurality of the pressure chambers and the pistons facing the pressure chambers. The stem opens and closes the valve body by moving up and down,
The actuator according to any one of claims 1 to 9 , further comprising an opening/closing detection sensor that detects opening/closing of the valve body as the piston moves up and down based on a change in distance to the piston. An air operated valve comprising the actuator according to any one of claims 1 to 10 .

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