JPH06129564A - Valve actuator - Google Patents

Abstract

PURPOSE:To provide a valve actuator which can simply and accurately set a minute degree of opening and a large degree of opening. CONSTITUTION:When a pressure medium is supplied into a second cylinder 23, a second piston 21 moves for a comparatively short stroke. Therein the second piston 21 moves interlockingly a piston rod 19, whose motion is decelerated through assist mechanisms 16, 17, 18 and transmitted to the valve element 8 of a valve device 1. Accordingly the motion of the second piston 21 opens the valve device 1 slightly. If then the pressure medium is supplied into a first cylinder 22, a first piston 20 travels for a comparatively long stroke. The motion of this first piston 20, i.e., motion of piston rod 19, is transmitted to the valve element 8 via the assist mechanisms so that the valve device 1 is opened still larger.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention particularly relates to a valve actuator which is advantageously applied to a slow vent valve which is used by being interposed between a vacuum chamber and an atmospheric pressure side or a portion having a relatively high pressure difference. .

[0002]

2. Description of the Related Art For example, when a vacuum chamber used in semiconductor manufacturing or the like is changed from a vacuum state to an atmospheric pressure state, the atmosphere must be gradually introduced into the vacuum chamber so that particles do not rise. . In this case, conventionally
Since it is not possible to accurately set the minute opening and the large opening with one valve device, as shown in FIG.
1 and the atmosphere are connected by a large-diameter vent valve 02, a bypass passage 03 is provided so as to bypass the large-diameter vent valve 02, and another vent valve 04 and throttle 05 are connected in series in the bypass passage 03. The arrangement arranged in was adopted.

In this structure, first, only another vent valve 04 is opened so that the atmosphere is gradually introduced into the vacuum chamber 01 through the throttle 05 to the extent that particles do not rise, and then, When the atmospheric pressure in the vacuum chamber 01 slowly increased and reached a predetermined pressure, the large-diameter vent valve 02 was opened. At this point, the vacuum chamber 01
Since the difference between the internal pressure and the atmospheric pressure is not so large, despite opening the large-diameter vent valve 02,
Particles are unlikely to fly up due to the introduced atmosphere.

[0004]

However, in such a structure, in addition to the large-diameter vent valve 02, it is necessary to provide another bypass valve 03 having a vent valve 04 and a throttle 05. In addition to complicating the manufacturing cost, a special control device for operating the two vent valves over time is required, resulting in a large increase in manufacturing cost. Further, in the bypass passage 03, the fluid is restricted by the throttle 05.
Since it flows through another vent valve 04, it was not always easy to set the flow rate accurately.

The present invention has been made by paying attention to such a problem, and simplifies the structure by eliminating the need for a vent valve and a separate vent valve, which have been conventionally required, and at the same time, enables a small opening and a large opening. An object is to provide a valve actuator that can be set accurately.

[0006]

In order to achieve the above object, a valve actuator of the present invention is a valve actuator driven by a pressure medium for transmitting a valve operating force to a valve device through a boosting mechanism. The valve actuator includes a piston cylinder unit, and the piston cylinder unit includes a piston rod guided in an intermediate guide portion, and first and second piston rods arranged at both ends of the piston rod. It is composed of a piston and first and second cylinders for accommodating the respective pistons. The first piston is integrally fixed to the piston rod and can move in a relatively long stroke. The second piston is fitted in the piston rod so as to be free to move in the axial direction and to come into contact with the stopper at the end of the piston rod. It is characterized in that for moving the target short stroke.

[0007]

First, when the pressure medium is supplied into the second cylinder and the second piston is biased by the pressure of the pressure medium, the second piston moves in a relatively short stroke. At this time, the second piston contacts the stopper at the end of the piston rod to interlock the piston rod,
The movement of the piston rod is decelerated via the booster mechanism and then transmitted to the valve body of the valve device. Therefore, movement of the second piston causes the valve device to open only slightly. Next, when the pressure medium is supplied into the first cylinder,
The pressure of this pressure medium causes the first piston to travel a relatively long stroke. In this case, the piston rod moving with the first piston is free to pass through the stationary second piston. The movement of the first piston, that is, the movement of the piston rod is also transmitted to the valve body via the booster device, and further opens the valve device. However, the valve opening at this time is relatively large according to the moving distance of the first piston.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

In the embodiment of FIG. 1, a valve device 1 configured as a lift valve is provided in the valve chamber 4 and a valve box 5 having inflow / outflow passages 2 and 3 and a substantially cylindrical valve chamber 4. A valve seat 6 and a valve body 8 seated on the valve seat 6 via a diaphragm 7.
And a lid 9 which is inserted into the valve chamber 4 and slidably accommodates the valve body 8. In this case, an annular projection 10 is formed on the lower portion of the inner wall of the valve chamber 4, and the diaphragm 7 is sandwiched between the upper end surface of the projection 10 and the front end surface of the lid 9. The diaphragm 7 is made of a spring elastic material, and is curved upward in an unloaded state. Therefore, the diaphragm 7
The valve body 8 placed on the upper side is always urged upward by the diaphragm 7, that is, in the valve opening direction.

The lid 9 inserted into the valve chamber 4 is fixed to the valve box 5 with a nut 11, and the lid 9 is attached to the valve box 5.
A center through hole 12 is provided in the center through hole 12, and a valve body 8 and an operating rod 13 for vertically moving the valve body 8 are housed in the center through hole 12. Then, the valve operating force of the valve actuator 14 is transmitted to the upper end of the operating rod 13 protruding from the lid 9. Therefore, in this case, the valve body 8, the diaphragm 7, and the operation rod 13 form a valve member.

The valve actuator 14 comprises a booster mechanism and a piston cylinder unit. As is known, this boosting mechanism is rotatably supported by the intermediate guide portion 15.
A disc cam 16 that engages with the upper end of the operation rod 13 and a piston rod 19 that has a rack portion 18 that meshes with external teeth 17 formed on the top of the disc cam 16. In this case, the rotation center C of the disc cam 16 is eccentric from the geometrical center position CG of the disc cam 16 and is located on the central axis A of the valve body 8 and the operating rod 13. However, the outer teeth 17 of the disc cam 16 should be arranged in an arc shape around the rotation center C of the disc cam 16.

The piston cylinder unit of the valve actuator 14 includes the piston rod 19 guided in the intermediate guide portion 15, and first and second pistons 20 and 21 arranged at both ends of the piston rod 19, respectively. First and second cylinders 22, which house each piston 20, 21;
And 23. The first piston 20 is fitted into the small diameter portion 24 of the piston rod 19, and is integrally connected to the piston rod 19 by a retaining ring 25.
Further, the compression spring 2 compressed inside the first cylinder 22
Always biased outward by 6. A full-opening port 27 is provided at the outer end of the first cylinder 22, and the pressure medium can be supplied into the first cylinder 22 via the full-opening port 27. In this case, the first piston 20 can move in a comparatively long stroke defined by the contact surface 28 provided in the first cylinder 22 and the side surface 29 of the intermediate guide portion 19.

The second piston 21 is the piston rod 1
9 is fitted so as to be movable in the axial direction and abuttable on a stopper 30 at the end of the piston rod. In this case, the piston rod 19 has a sealing disc 31 immovably arranged between the intermediate guide portion 15 and the second cylinder 23.
Through the pressure medium passage 32 provided in the seal disc 31 and the fine opening port 33 provided in the intermediate guide portion 15, the pressure medium is introduced into the second cylinder 23. Can be supplied. A stroke adjusting stopper 35 that provides an adjustable contact surface 34 for the second piston 21 is screwed into the outer end portion of the second cylinder 23. The stroke adjusting stopper 35 can be fixed at an arbitrary position by a fixing screw 36 screwed into the peripheral wall portion of the second cylinder 23. Further, the stroke adjusting stopper 35 protruding from the second cylinder 23.
At the outer end of the operation handle 37, for example, the fixing screw 3
It is fixed by 8. This stroke adjustment stopper 3
The stroke of the second piston 21 defined by 5 is shorter than the stroke of the first piston 20.

In addition, 39 to 44 are seal rings, 45 and 46 are bushes for ensuring smooth sliding of the piston rod 19, and 47 and 48 preliminarily limit the total stroke of the piston rod 19. Limit pin and limit groove.

Next, the operation of the valve actuator 14 will be described. In the initial state shown in FIG. 1, the valve body 8 and the operating rod 13 are pressed downward by the disc cam 16 against the urging force of the diaphragm 7, whereby the valve body 8 passes through the diaphragm 7. Seated on valve seat 6. That is, the lift valve 1 is closed.

Next, in order to open the lift valve 1, the pressure medium is supplied into the second cylinder 23 through the small opening port 33 and the pressure medium passage 32, and the second piston 21 is moved. When energized by the pressure of this pressure medium, the second piston 21 moves in a relatively short stroke defined by the stroke adjusting stopper 35. At this time, the second piston 21 has the stopper 30 at the end of the piston rod 19.
And the piston rod 19 is interlocked. The movement of the piston rod 19 is performed by the booster mechanisms 16, 17, 1
After being decelerated via 8, the operating rod 1 as a valve member
3 which causes the valve body 8 to rise only slightly, i.e. open. The minute opening of the valve body 8 at this time is
The stroke adjusting stopper 35 can be set with extremely high precision. In this case, the first piston 20
Also follows the movement of the second piston 21 and the piston rod 19 and also slightly moves against the compression spring 26.

Next, when a pressure medium is supplied into the first cylinder 22 through the full opening port 27, the pressure of the pressure medium causes the first piston 20 to come into contact with the side surface 29 of the intermediate guide portion 15. Travel a relatively long distance between. In this case, the piston rod 19 that moves together with the first piston 20 freely passes through the insertion hole of the second piston 21, which is in contact with the stroke adjusting stopper 35 and is stationary. The movement of the first piston 20, that is, the movement of the piston rod 19 is also transmitted to the operating rod 13 after being decelerated via the boosting mechanisms 16, 17, and 18 to further open the valve body 8. However, the valve opening at this time is relatively large according to the moving distance of the first piston 20.

In order to close the lift valve 1 again, the pressure medium in the first and second cylinders 22 and 23 may be opened to the outside. In this case, the first and second pistons 20 and 21 and the piston rod 19 are returned to the initial position by the urging force of the compression spring 26, whereby the operating rod 13 and the valve body 8 are moved to the disc cam 16. Via, is pressed downward against the biasing force of the diaphragm 7.

2 and 3 show two other embodiments of the present invention. In the case of the embodiment shown in FIG. 2, the first piston 20 is double-acting and is selectively urged in both directions by the pressure medium.
That is, in this embodiment, instead of the compression spring 26 of the embodiment shown in FIG. 1, a seal disk 51 having a pressure medium passage 50 and a fully closing port 52 provided in the intermediate guide portion 15 are arranged. Has been done.

In the case of the embodiment shown in FIG. 3, the disc cam 1
The engagement structure between 6 and the piston rod 19 is different from that of the other embodiments. That is, the link 54 having the slot 53 is integrally fixed to the disc cam 16,
A pin 55 that engages with the slot 53 of the link 54 is planted in the piston rod 19.

The structure of the present invention is not limited to the above embodiment. For example, different configurations of the embodiments shown in FIGS. 2 and 3 can be combined to form still another embodiment. In short, the valve actuator of the present invention can easily realize a relatively small valve opening and a relatively large valve opening set in advance, and is suitable for any application requiring such valve operation. Applicable.

[0022]

By using the valve actuator of the present invention, the valve opening of the valve device can be set extremely accurately from a small opening to a large opening. Therefore, since it is no longer necessary to additionally provide a bypass passage having another vent valve and a throttle for achieving a minute flow rate as in the conventional case, the overall structure is simplified and the manufacturing cost is reduced. Significantly reduced.

[0023]

[Brief description of drawings]

FIG. 1 is a sectional view of a first embodiment of a valve actuator according to the present invention.

FIG. 2 is a sectional view of a second embodiment of the valve actuator.

FIG. 3 is a sectional view of a third embodiment of the valve actuator.

FIG. 4 is a schematic view showing a usage mode of a conventional valve device.

[Explanation of symbols]

1 Valve device 2 Inflow / outflow passage 3 Inflow / outflow passage 4 Valve chamber 5 Valve box 6 Valve seat 7 Diaphragm 8 Valve body 9 Lid body 10 Protrusion 11 Nut 12 Center through hole 13 Operation rod 14 Valve actuator 15 Intermediate guide portion 16 Disc cam 17 External Teeth 18 Rack Part 19 Piston Rod 20 1st
Piston 21 second piston 22 first
Cylinder 23 Second cylinder 24 Small diameter portion 25 Snap ring 26 Compression spring 27 Full opening port 28 Abutment surface 29 Side surface 30 Stopper 31 Seal disc 32 Pressure medium passage 33 Small opening port 34 Abutment surface 35 Stroke adjustment stopper 36 Fixing Screw 37 Operation Handle 38 Fixing Screw 50 Pressure Medium Passage 51 Seal Disc 52 Port for Full Closing 53 Slot 54 Link 55 Pin

Claims (6)

[Claims] 1. A valve actuator driven by a pressure medium for transmitting valve operating force to a valve device via a booster mechanism, the valve actuator including a piston cylinder unit, the piston cylinder The unit consists of a piston rod guided in the intermediate guide,
The piston rod comprises first and second pistons arranged at both ends of the piston rod, and first and second cylinders for accommodating the respective pistons. The first piston is integrally fixed to the piston rod. The second piston is fitted to the piston rod so as to be free to move in the axial direction and to come into contact with the stopper at the end of the piston rod. The valve actuator is characterized in that it moves in a relatively short stroke. 2. The stroke of the second piston is regulated by being brought into contact with a stroke adjusting stopper provided on the second cylinder when the second piston is actuated by the pressure medium. Valve actuator described in. 3. The first piston is urged toward one side by a spring and is selectively urged toward the other side by a pressure medium.
Valve actuator described in. 4. The valve actuator according to claim 1, wherein the first piston is a double-acting type and is selectively biased in both directions by a pressure medium. 5. The boost mechanism includes a disc cam engaged with the valve member, outer teeth formed on the disc cam, and a rack portion formed on the piston rod, which meshes with the outer teeth. The valve actuator according to any one of claims 1 to 4, which is configured by. 6. The booster mechanism is attached to a disc cam engaged with the valve member, a link integrally fixed to the disc cam, and the piston rod engaged with the link. The valve actuator according to any one of claims 1 to 4, which is constituted by a pin.