KR20100002116A - Vacuum valve - Google Patents

Abstract

PURPOSE: A vacuum valve is provided to control a flow rate by changing a stroke of a valve element by individually moving a first piston and a second piston. CONSTITUTION: A vacuum valve(1) bonds a second piston(27) with an upper lid(22) by supplying the compression air to a lower room from a second operation port(33). The stroke control unit(38) is contacted with the second piston by a control screw. The stroke control unit is fixed in a main axis(11) by a fixing screw(39). The second piston is bonded with the upper lid. The stroke control unit is descended with the rotation. The movement quantity of the main axis and the second piston is increased according to the descend operation of the stroke control unit by the stroke control unit. The stroke of a valve element(7) is set according to the rotation of the stroke control unit.

Description

Vacuum Valve {VACUUM VALVE}

The present invention relates to a vacuum valve element capable of controlling the exhaust flow rate stepwise, for example, when evacuating a vacuum chamber of a semiconductor manufacturing apparatus.

In the semiconductor manufacturing apparatus, when evacuating the vacuum chamber, a large amount of gas flows because the gas in the vacuum chamber is rapidly discharged, and small particles (dust) adhered to the inner wall and the flow path of the vacuum chamber. On the other hand, if the exhaust flow rate is too limited, the exhaust time becomes long and adversely affects the production duct. Therefore, for example, Patent Document 1 proposes a vacuum valve that prevents generation of small particles by switching the exhaust flow rate from a small flow rate to a large flow rate.

7-9 is sectional drawing which showed embodiment of the vacuum valve 100 of patent document 1, FIG. 7 is a valve closed state, FIG. 8 is a slow exhaust state, and FIG. 9 is a rapid exhaust state. to be.

The vacuum valve 100 is provided with a valve seat 104 in a valve body 103 having a pump port 101 and a chamber port 102. The valve element 105 is fixed to the lower end of the main shaft 107 and is normally biased in the valve seat direction by the return spring 106. The valve element 105 is equipped with an annular sealing member 122 to block the flow path by pressing the annular sealing member 122 against the valve seat 104.

The cylinder tube 108 is fixed to the valve body 103. The bottomed hole is opened in the both ends of the cylinder tube 108, and the 1st piston seal 111 and the 2nd are closed by blocking the bottomed hole with the bottom lid 109 and the top lid 110. As shown in FIG. The piston seal 112 is formed. The main shaft 107 penetrates the bottom lid 109, the intermediate wall 113 and the upper lid 110 installed between the bottom lid 109, the first piston chamber 111 and the second piston chamber 112 from the valve body 103. Doing.

The 1st piston 114 is fixed to the main shaft 107, and the 1st piston 114 is arrange | positioned so that the sliding to the 1st piston chamber 111 is possible. In addition, the main shaft 107 is inserted into the second piston 115 formed by being inserted into the second piston chamber 112. A locking member 121 is attached to the upper end of the main shaft 107 using the nut 116. The first piston chamber 111 and the second piston chamber 112 are hermetically partitioned by the first piston 114 and the second piston 115, respectively, so that the first piston 114 and the second piston 115 are closed. In the lower chamber partitioned by, the first operation port 117 and the second operation port 118 opened in the cylinder tube 108 communicate with each other.

The adjustment handle 119 is attached to the upper lid 110 with a screw, and the lower end thereof is disposed in the second piston chamber 112 so as to be able to move forward and backward. The adjusting handle 119 is fixed at a predetermined position by the fixing screw 120.

As shown in FIG. 7, the vacuum valve 100 operates air from the first operating port 117 and the second operating port 118 to the first piston chamber 111 and the second piston chamber 112. In the case of not supplying, the valve element 105 is added to the return spring 106 and joined to the valve seat 104.

When slow-emission is performed in this state, operation air is supplied to the 2nd piston chamber 112 from the 2nd operation port 118, as shown by the dot part of FIG. The second piston 115 rises alone by the pressure of the operation air until it hits the locking member 121, and then rises integrally with the main shaft 107. As a result, the valve element 105 fixed to the lower end of the main shaft 107 is separated from the valve seat 104. The second piston 115 may ascend until it engages with the lower end of the adjustment handle 119, and movement is limited at that position. Therefore, the rise of the main shaft 107 and the valve element 105 also stops, and the valve opening state suitable for slow exhaust is maintained. Accordingly, the vacuum valve 100 exhausts a small flow rate from the chamber port 102 to the pump port 101, and can adjust the pressure in the vacuum chamber so as not to cause small particles.

When rapid exhaust is performed, operation air is supplied to the 1st operation port 117, as shown by the dot part of FIG. By the pressure of the operation air, the first piston 114 rises integrally with the main shaft 107 against the force of the return spring 106. The vacuum valve 100 can exhaust a large flow rate from the chamber port 102 to the pump port 101 by raising the valve element 105 integrally with the main shaft 107 to increase the valve opening degree.

When the exhaust in the vacuum chamber is finished, the operation air is discharged from the first operation port 117 and the second operation port 118. Then, as shown in FIG. 7, the main shaft 107 is lowered by the force of the return spring 106 to join the valve element 105 to the valve seat 104. Moreover, the 2nd piston 115 descends with discharge of operation air from the 2nd operation port 118, and is spaced apart from the adjustment handle 119. FIG.

Therefore, according to the conventional vacuum valve 100, exhaust flow volume can be controlled in steps by supply and stop of operation air to the 1st operation port 117 and the 2nd operation port 118. FIG.

[Patent Document 1] Japanese Laid-Open Patent 2001-12649

However, the conventional vacuum valve 100 could not adjust the home position of the adjustment handle 119 which makes flow volume zero after product assembly. Therefore, even if the adjustment handle 119 is rotated, there exists a case where the operation dead zone which cannot adjust a valve flow volume exists.

Specifically, the vacuum valve 100 rises together with the main shaft 107 after the second piston 115 is joined to the locking member 121. And the 2nd piston 115 raises with the main shaft 107 until it contacts a lower end part of the adjustment handle 119, and movement is restrict | limited. For this reason, in the conventional vacuum valve 100, the distance between the 2nd piston 115 and the adjustment handle 119 becomes the stroke of the valve element 105, and as long as the adjustment handle 119 is located in the lower side. The stroke of the valve element 105 is shortened.

Such a vacuum valve 100 does not supply compressed air to the second piston chamber 112 at the time of assembly of the product, and the second piston 115 is connected to the intermediate wall 113 by the force of the return spring 106. In the state which arrange | positioned in the lower limit position joined to the to-being, it is fastened to the upper lid 110 until the adjustment handle 119 hits the 2nd piston 115. As a result, the vacuum valve 100 sets the origin position of the adjustment handle 119. Here, an origin position means the position used as the reference | standard which made flow volume zero. And, the adjustment handle 119 is rotated in the predetermined direction at the origin position and ascends, and is fixed to the upper lid 110 by the fixing screw 120, thereby the distance between the second piston 115, That is, the stroke of the valve element 105 is determined.

However, the stroke of the valve element 105 is actually determined by the distance from the joining of the second piston 115 to the locking member 121 and then to the adjusting handle 119. The distance between the second piston 115 and the locking member 121 changes depending on the amount of bending of the annular sealing member 122. This also changes the stroke of the valve element 105.

That is, for example, when the bending amount of the annular sealing member 122 is large, the distance between the second piston 115 and the locking member 121 is shortened, and the second piston 115 is formed with a main shaft ( Since the distance for lifting 107 and the valve element 105 becomes long, the stroke of the valve element 105 becomes large. On the other hand, for example, when the amount of warpage of the annular sealing member 122 is small, the distance between the second piston 115 and the locking member 121 becomes long, and the second piston 115 is the main shaft ( Since the distance for lifting 107 and the valve element 105 becomes short, the stroke of the valve element 105 becomes small.

Therefore, by making the adjustment handle 119 collide with the second piston 115 disposed at the lower limit position, the origin position of the adjustment handle 119 is determined, and the adjustment handle 119 is rotated a predetermined number of times based on the origin position. Even if it is, the stroke of the valve element 105 cannot be adjusted to the set value unless the distance between the second piston 115 and the locking member 121 is uneven due to the bending amount of the annular sealing member 122. . For example, when the bending amount of the annular sealing member 122 is smaller than the design value, even if the adjustment handle 119 is rotated several times at the origin position, the second piston 115 is joined to the locking member 121. It may be joined to the lower end of the adjustment handle 119 before it may adjust the valve opening degree.

In addition, repeated use of the annular sealing member 122 deteriorates, and the amount of bending of the annular sealing member 122 at the time of closing the valve changes. On the other hand, the distance between the second piston 115 and the locking member 121 is uniquely determined at the time of product assembly. Therefore, in the conventional vacuum valve 100, even if the bending amount of the annular sealing member 122 at the time of valve closing changes after product assembly, the adjustment handle according to the change of the bending amount of the annular sealing member 122 is changed. The origin position of (119) could not be adjusted.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a vacuum valve capable of simply and accurately adjusting the origin position of a stroke adjusting member even after product assembly.

The vacuum valve related to this invention has the following structures.

(1) The valve seat of the body provided between the chamber port and the pump port is elastically deformed and brought into close contact with the annular sealing member attached to the valve element to shut off the chamber port from the pump port. A first piston and a second piston are slidably disposed in the first piston chamber and the second piston chamber installed in the cylinder tube such that a main shaft connected to the valve element is fixed to the first piston and inserted into the second piston. And a locking member to which the second piston is engaged, and in which the stroke of the valve element is adjusted stepwise by operating the first and the second piston separately, 2, an adjustment screw portion is formed on an outer circumferential surface of the portion to be inserted into the piston seal, and the locking member is screwed to the adjustment screw portion. It is a stroke adjustment member, and has a fixing member which fixes the said stroke adjustment member with respect to the said main shaft.

(2) In the invention described in (1), the cylinder tube has a cylindrical shape with openings at both ends, the inner space is divided by an intermediate wall, and a bottom lid is provided at one opening to form the first piston seal. The upper lid is provided in another opening to form the second piston seal, and the upper lid is formed with a through hole for inserting the main shaft to which the stroke adjusting member is screwed.

(3) In the invention described in (1) or (2), the second piston is in surface contact with the upper lid.

(4) In the invention as described in any one of (1)-(3), the screw diameter of the said adjustment screw part is smaller than the diameter of the said main shaft.

The vacuum valve of the present invention elastically deforms the annular sealing member of the valve element between the valve seat and close to the valve seat, thereby blocking the gap between the chamber port and the pump port. When the 2nd piston moves to the position joined to the stroke adjustment member, it will move integrally with a main shaft. If the second piston is joined to the upper lid, movement is limited. The valve element is lifted from the valve seat only to the distance from joining to the stroke adjusting member to joining to the upper lid to adjust the flow rate of the fluid flowing from the chamber port to the pump port. On the other hand, the first piston starts to move and moves integrally with the main shaft. The valve element lifts only the amount of movement of the first piston from the valve seat to adjust the flow rate of the fluid flowing from the chamber port to the pump port. Therefore, the vacuum valve can change the stroke of the valve element and control the flow rate step by step by moving the first piston and the second piston separately.

As the second piston is arranged near the second piston, the distance for moving alone is shortened. That is, in the vacuum valve, the stroke of the valve element is increased because the distance that the second piston moves together with the main shaft becomes longer as the stroke adjusting member is positioned and fixed near the second piston. On the other hand, when the second piston is joined to the upper lid, the movement is limited. Therefore, when the vacuum valve is fastened to the adjusting screw until the stroke adjusting member hits the second piston in a state where the second piston is joined to the upper lid, the second piston is the sole member when the stroke adjusting member is fixed by the fixing member. Move to and bond to the top lid. That is, the vacuum valve causes the stroke of the valve element to be zero.

The vacuum valve can uniquely determine the joining position of the upper lid and the second piston for each product, even if the assembly dimensions of the parts are not uniform for each product or the elastic deformation amount of the annular sealing member is different. Therefore, even after assembling the product, the vacuum valve strokes when the stroke adjusting member is fastened to the adjusting screw and the stroke adjusting member is fixed by the fixing member until the second piston is hit by the second piston while the second piston is joined to the upper lid. The origin position of the adjustment member can be adjusted. Therefore, according to the vacuum valve element of this invention, even after the product assembly, the origin position of a stroke adjustment member can be adjusted simply and correctly.

The vacuum valve of this invention forms the through hole in the upper lid which forms the 2nd piston seal which can be loaded with a 2nd piston so that a sliding action is possible, and inserts the main shaft into which the stroke adjustment member is screwed. For this reason, in the vacuum valve of the present invention, the shock when the second piston is joined to the upper lid is not transmitted to the stroke adjusting member, so that the stroke adjusting member is loosened and no positional deviation occurs.

In the vacuum valve of the present invention, since the second piston is widely in surface contact with the upper lid, the vacuum valve has a wide impact on the upper lid when the second piston is joined to the upper lid, and thus the material strength of the upper lid or the cylinder tube. There is no need to raise it. Therefore, according to the vacuum valve element of the present invention, a material having a low material strength can be applied to a cylinder tube or an upper lid to reduce the weight and at the same time reduce the cost.

In the vacuum valve of the present invention, since the screw diameter of the adjusting screw portion is smaller than the diameter of the main shaft, the screw of the adjusting screw portion can be formed with a small pitch. Therefore, the vacuum valve of this invention can finely adjust the position of a stroke adjustment member by screw movement with an adjustment screw part.

EMBODIMENT OF THE INVENTION Hereinafter, one Embodiment of the vacuum valve concerning this invention is described with reference to drawings.

<Configuration of vacuum valve>

1 to 3 are sectional views showing an embodiment of the vacuum valve 1, FIG. 1 is a valve closed state, FIG. 2 is a slow exhaust state, and FIG. 3 is a rapid exhaust state. In FIGS. 1-3, the stroke adjustment member 38 is arrange | positioned in the lowest position. 4 is a top view of the vacuum valve 1 shown in FIG.

The vacuum valve 1 shown in FIGS. 1-4 is provided between the chamber of a semiconductor manufacturing apparatus, and a vacuum pump similarly to a prior art.

As shown in FIGS. 1-3, the vacuum valve 1 is comprised from the lower valve part X and the upper drive part Y. As shown in FIG. The vacuum valve 1 moves the stroke of the valve element 7 by separately moving the first piston 26 and the second piston 27 in the first piston chamber 24 and the second piston chamber 25. Change, and flow control step by step.

As shown in FIGS. 1-3, the valve part X is provided in the cylindrical valve body 2. As shown in FIG. As for the valve body 2, the pump port 3 connected to the vacuum pump which is not shown in figure protrudes to the side, and the chamber port 4 connected to the chamber which is not shown in figure protrudes below. In the valve body 2, the valve seat 6 is formed in a flat surface at the inlet of the valve hole 5 on the chamber port 4 side. The valve element 7 is provided in the valve body 2 so that the valve seat 6 can be joined and separated.

The valve element 7 is an annular sealing member 10 arranged in an ant groove formed between the valve block 8 and the support plate 9 and fixedly fixed to the lower end of the main shaft 11 with a nut 12. It is. The annular sealing member 10 is formed in an annular shape with the material which has elastic force, such as rubber | gum and resin. The lower end of the bellows 13 is connected to the valve block 8 constituting the valve element 7. The upper end of the bellows 13 is connected to an annular fixed plate 14 disposed between the valve portion X and the drive portion Y. Thus, the bellows 13 expands and contracts with the vertical movement of the main shaft 11 and the valve element 7.

On the other hand, the upper drive part Y is comprised in the cylinder tube 20, as shown to FIG. The cylinder tube 20 cut | disconnects metal pipe | tubes, such as aluminum shape | molded by extrusion process etc. to predetermined length. The cylinder tube 20 is equipped with a bottom lid 21, an upper lid 22, and a partition plate (an example of an intermediate wall; 23) to form a first piston chamber 24 and a second piston chamber 25, The first piston 26 and the second piston 27 are loaded in the first and second piston chambers 24 and 25 so as to be able to slide.

1 to 3, a C ring 31 is attached to the inner circumferential surface of the cylinder tube 20, and a partition plate 23 is inserted from the upper opening so as to collide with the C ring 31. . An annular groove for mounting the C ring 32 is formed in the cylinder tube 20, and a step for determining the position of the upper lid 22 is provided at the rear of the annular groove. 1 to 4, the upper lid 22 is supported so as not to shake in the axial direction between the step of the cylinder tube 20 and the C ring 32, and between the partition plate 23 The 2nd piston seal 25 is formed.

As shown in FIGS. 1-3, the 2nd piston chamber 25 is divided into the upper chamber 25A and the lower chamber 25B by the 2nd piston 27. As shown in FIG. The second operation port 33 formed in the cylinder tube 20 communicates with the base 25B through the communication hole 34. On the other hand, the upper chamber 25A communicates with the outside air through the through hole 22a formed in the upper lid 22. The axial part 27a is provided in the 2nd piston 27 continuously in the axial direction from one end surface. The shaft portion 27a of the second piston 27 is inserted into the holding hole 23a formed in the center of the partition plate 23 so as to be slidable, and the compression supplied from the second operation port 33 to the base 25B is provided. It rises in the 2nd piston chamber 25 by the pressure of air.

The cylinder tube 20 is provided with an annular groove for attaching the C ring 28 to the inner circumference of the lower opening, and a step for determining the position of the bottom lid 21 is provided at the rear of the annular groove. The bottom lid 21 is supported so as not to shake in the axial direction between the step of the cylinder tube 20 and the C ring 28 to form a first piston seal 24 between the partition plate 23. Doing.

The 1st piston chamber 24 is divided into the upper chamber 24A and the lower chamber 24B by the 1st piston 26 so that it may be sealed. The first operation port 29 formed in the cylinder tube 20 communicates with the basement 24B via the communication hole 30. On the other hand, the loss 24A communicates with the outside air through the breathing hole 18. The 1st piston 26 is raised in the 1st piston chamber 24 by the pressure of the compressed air supplied from the 1st operation port 29 to the base 24B.

As shown in FIGS. 1 to 3, the driving unit Y accumulates coaxially with the valve body 2 via the fixing plate 14, and as shown in FIG. 4, from above. Four bolts 19 are fixed to the valve body 2. As a result, the fixing plate 14 is sandwiched between the cylinder tube 20 and the valve body 2 to determine and fix the position of the bellows 13.

The pipe part 21b is continuously provided in the bottom cover 21 in the axial direction, and the pipe part 21b protrudes from the fixing plate 14 into the bellows 13 inside. The main shaft 11, which is connected to the valve element 7, is inserted into the pipe portion 21b and from the valve body 2 into the cylinder tube 20.

A step 11a for determining the position of the first piston 26 is provided on the main shaft 11, and a male screw portion 11b is formed on the upper end side of the step 11a. And the main shaft 11 makes the upper side of the male screw part 11b thinner than the male screw part 11b, and comprises the adjustment rod part 11c. The adjusting rod part 11c of the main shaft 11 is inserted in the through hole 27b of the second piston 27 and the through hole 22a of the upper lid 22 with a gap therebetween, and is separated from the upper lid 22. It protrudes. 11 d of adjustment screw parts are formed in the outer peripheral surface of the part arrange | positioned at the 2nd piston chamber 25 of the adjustment rod part 11c.

The first piston 26 is inserted into the main shaft 11 so as to collide with the step 11a at the upper end of the main shaft 11, and the main shaft 11 by fixing the nut 37 to the male screw portion 11b. It is fixedly installed.

The stroke adjustment member 38 is screwed to the adjustment screw portion 11d of the main shaft 11. The stroke adjustment member 38 is positioned and fixed with respect to the main shaft 11 by the fixing screw 39. As for the main shaft 11, the holding | maintenance part 40 is attached to the upper end side of 11 d of adjustment screw parts. As shown in FIG. 1, when the second piston 27 is at the lower limit position joined to the partition plate 23, the position fastened to the adjusting threaded portion 11d until it hits the second piston 27 is It becomes the lowest point position of the stroke adjustment member 38. In addition, the position where the upward movement of the stroke adjustment member 38 is limited by the holding | maintenance part 40 becomes the highest point position of the stroke adjustment member 38. As shown in FIG.

The return spring 41 is extended between the bottom lid 21 and the valve element 7, and the valve element 7 is normally added to the valve seat 6 direction. The return spring 41 is covered with the bellows 13 so that small particles and the like do not flow out of the flow path.

<Description of operation>

In the vacuum valve 1 which consists of such a structure, vacuum exhaust is performed by the following functions. When the valve is closed, the vacuum valve 1 has a state in which the annular sealing member 10 of the valve element 7 is joined to the valve seat 6, so that the valve hole 5 is blocked, as shown in FIG. do. This is because the valve element 7 is pushed downward only by the elastic force of the return spring 41. And when vacuum evacuation of the vacuum chamber not shown connected to the chamber port 4 is performed, operation | movement by two steps for slow-speed exhaust and rapid exhaust as follows is performed.

First, in order to perform slow exhaust, compressed air is supplied to the vacuum valve 1 from the 2nd operation port 33 to the base 25B of the 2nd piston seal 25 to the vacuum valve 1, as shown by the dot part of FIG. do. Therefore, the 2nd piston 27 is pressurized from below and it rises to push up the stroke adjustment member 38. FIG. Therefore, the main shaft 11 is raised to the second piston 27 against the biasing force of the return spring 41 downward, and pulls the valve element 7 in the direction away from the valve seat 6. . On the other hand, after lifting the main shaft 11, the second piston 27 touches the upper lid 22 when the predetermined amount rises again, the movement thereof is limited. Therefore, the rise of the main shaft 11 and the valve element 7 also stops, and the position shown in FIG. 2, ie, the state of the valve opening suitable for performing slow exhaust, is maintained.

The vacuum valve 1 has a small valve opening degree in the slow exhaust state shown in FIG. 2, and the fluid flowing between the pump port 3 and the chamber port 4 is connected to the valve seat 6 and the valve element 7. It flows through the gap, and its flow rate is limited. Therefore, the gas in a vacuum chamber does not flow rapidly, and slow exhaust gas which does not produce a small particle is performed. And since the pressure in a vacuum chamber became a predetermined value, continuous rapid exhaust is performed.

When rapid exhaust is performed, as shown by the dot part of FIG. 3, compressed air is supplied to the vacuum valve 1 from the 1st operation port 29 to the base 24B of the 1st piston chamber 24. As shown in FIG. For this reason, the first piston 26 is pushed downward and ascends in the first piston chamber 24. At this time, since the main shaft 11 is fixed with respect to the first piston 26, the main shaft 11 also rises with the rise of the first piston 26. Therefore, the valve element 7 fixed to the main shaft 11 also rises against the force of the return spring 41, and the valve opens with the valve opening degree enlarged as shown in FIG.

In the case where the vacuum valve 1 is in the rapid exhaust state shown in FIG. 3, the valve opening degree is large, and the flow rate flowing between the pump port 3 and the chamber port 4 increases, and the gas remaining in the vacuum chamber rapidly increases. Is exhausted. And when the gas exhaust in a vacuum chamber is complete | finished, compressed air will escape | release out of the 1st operating port 29 and the 2nd operating port 33, and the 1st piston 26 and the 2nd piston 27 will push from below It releases from the pressing force by the compressed air which it raised. Therefore, the valve element 7, the main shaft 11, the first piston 26, and the second piston 27 are added downward by the return spring 41 and return to the state shown in FIG. 1. That is, the annular sealing member 10 of the lowered valve element 7 is joined to the valve seat 6 to elastically deform, and the pump port 3 and the chamber port 4 are blocked.

<Flow rate adjustment method in slow exhaust>

By the way, when slow exhaustion is performed, it is necessary to adjust a valve opening degree according to exhaust flow volume. In this case, the vacuum valve 1 adjusts the stroke of the valve element 7 by rotating the stroke adjustment member 38 disposed at the origin position in a predetermined direction, and sets the flow rate at slow exhaust to the target flow rate. .

FIG. 5: is a figure explaining the method of adjusting the position of the stroke adjustment member 38 of the vacuum valve 1 shown in FIG. 1 to an origin position.

The vacuum valve 1 supplies compressed air from the second operation port 33 to the base 25B to join the second piston 27 to the upper lid 22. In this state, the stroke adjustment member 38 is fastened to the adjustment screw portion 11d until the stroke adjustment member 38 strikes the second piston 27. Then, the stroke adjusting member 38 is fixed to the main shaft 11 by the fixing screw 39. When the second piston 27 is joined to the upper lid 22, it cannot rise further. Therefore, when the position of the stroke adjustment member 38 is determined while striking the stroke adjustment member 38 against the second piston 27 joined to the upper lid 22, the second piston 27 is the upper lid 22. ), The valve element 7 is not lifted from the valve seat 6 until it is joined alone. Therefore, the home position at the time of closing the valve of the stroke adjustment member 38 is uniquely determined.

And the stroke adjustment member 38 arrange | positioned at the origin position is rotated in a predetermined direction, and the stroke adjustment member 38 is lowered. As the stroke adjusting member 38 descends, the amount of movement in which the second piston 27 rises with the main shaft 11 increases, so that the valve element (when the second piston 27 joins the upper lid 22) The amount of 7) lifted from the valve seat 6 increases. That is, the stroke of the valve element 7 becomes large. Accordingly, the stroke of the valve element 7 can be set to set the flow rate to the target flow rate by rotating and lowering the stroke adjustment member 38 at the home position by the prescribed number of times.

As mentioned above, the vacuum valve 1 can make the pitch of the adjustment screw part 11d small, and can fine-adjust the position of the stroke adjustment member 38, and can control the exhaust flow volume at the time of slow exhaustion to a fine flow rate.

<Action effect>

Accordingly, the vacuum valve 1 of the present embodiment elastically deforms the annular sealing member 10 of the valve element 7 with the valve seat 6 and closely adheres to the valve seat 6, thereby providing a pump port 3. To and from the chamber port (4). When the 2nd piston 27 moves to the position joined to the stroke adjustment member 38, it moves with the main shaft 11 integrally. When the second piston 27 is joined to the upper lid 22, the movement is limited. The valve element 7 is only lifted from the valve seat 6 to the pump port 3 from the valve seat 6 by joining the stroke adjusting member 38 to the upper lid 22. Adjust the flow rate of the flowing fluid. On the other hand, the vacuum valve 1 moves integrally with the main shaft 11 at the same time as the first piston 26 starts to move. The valve element 7 lifts only the movement amount of the first piston 26 from the valve seat 6 to adjust the flow rate of the fluid flowing from the chamber port 4 to the pump port 3. Therefore, the vacuum valve 1 changes the stroke of the valve element 7 by moving the 1st piston 26 and the 2nd piston 27 separately, and controls the flow volume in steps.

As long as the 2nd piston 27 arrange | positions the stroke adjustment member 38 near the 2nd piston 27, the distance which moves independently becomes short. That is, since the vacuum valve 1 has a long distance that the second piston 27 moves with the main shaft 11 as the stroke adjusting member 38 is fixed to the vicinity of the second piston 27, The stroke of the valve element 7 becomes large. On the other hand, when the second piston 27 is joined to the upper lid 22, the movement is limited. Therefore, the vacuum valve 1 is attached to the adjustment screw part 11d until the stroke adjustment member 38 hits the second piston 27 in a state where the second piston 27 is joined to the upper lid 22. When the stroke adjustment member 38 is fixed to fix the screw and the screw 39 is fixed, the second piston 27 moves alone to be joined to the upper lid 22. That is, the stroke of the valve element 7 becomes zero in the vacuum valve 1.

The vacuum valve 1 is unique in the joint position of the upper lid 22 and the second piston 27 for each product, even if the assembly dimensions of the parts are not uniform for each product or the elastic deformation amount of the annular sealing member 10 is different. Can be determined by Therefore, even after assembling the product, the vacuum valve 1 has a stroke adjusting member on the adjusting screw portion 11d until it hits the second piston 27 in a state in which the second piston 27 is joined to the upper lid 22. If the 38 is fastened and the stroke adjusting member 38 is fixed with the fixing screw 39, the origin position of the stroke adjusting member can be adjusted. Therefore, according to the vacuum valve 1 of this embodiment, the origin position of the stroke adjustment member 38 can be adjusted simply and correctly even after product assembly.

The vacuum valve 1 of this embodiment forms the through-hole 22a in the upper lid 22 in which the 2nd piston seal 25 which mounted the 2nd piston 27 so that sliding was possible, and the through-hole is formed. The main shaft 11 on which the stroke adjusting member 38 is screwed is inserted into the 22a. Therefore, in the vacuum valve 1 of this embodiment, the shock when the 2nd piston 27 joins and catches on the upper lid 22 is not transmitted to the stroke adjustment member 38, but the stroke adjustment member 38 is carried out. Becomes loose and does not get out of position.

In the vacuum valve 1 of the present embodiment, since the second piston 27 is in surface contact with the upper lid 22 widely, the vacuum valve 1 is formed by connecting the second piston 27 to the upper lid 22. The impact in the case is widely dispersed in the upper lid 22, and it is not necessary to raise the material strength of the upper lid 22 or the cylinder tube 20. Therefore, according to the vacuum valve 1 of this embodiment, the material with low material strength can be applied to the cylinder tube 20 or the upper lid 22, and weight reduction can be carried out at the same time.

In the vacuum valve 1 of this embodiment, since the screw diameter of the adjustment screw part 11d is smaller than the diameter of the main shaft 11, the screw of the adjustment screw part 11d can be formed with a smaller pitch. Therefore, the vacuum valve 1 of this embodiment can adjust the position of the stroke adjustment member 38 more finely with the screw movement between the adjustment screw part 11d.

In addition, this invention is not limited to the vacuum valve of the said embodiment, A various change is possible in the range which does not deviate from the meaning.

For example, in the above embodiment, the piston seals 24 and 25 and the pistons 26 and 27 are in two stages, but the piston seal and the piston may be three or more stages.

For example, in the said embodiment, the stroke adjustment member 38 was positioned and fixed with the fixing screw 39. As shown in FIG. On the other hand, like the vacuum valve 1A shown in FIG. 6, the installation screw part 11e for installing the fixing screw 45 above the adjustment screw part 11d of the main shaft 11A is provided, and a fixed screw is provided. The stroke adjustment member 38 may be positioned and fixed at 45. And the compression spring 46 may be arrange | positioned between the upper lid 11 and the 2nd piston 27, and the vibration at the time of conveyance may be prevented.

For example, in the above embodiment, the bottom lid 21 and the top lid 22 are fixed with the C rings 28 and 32 with respect to the cylinder tube 20, but the bottom lid 21 and the top lid 22 are fixed. The cylinder tube 20 may be screwed in place.

For example, in the said embodiment, although the 1st piston chamber 24 and the 2nd piston chamber 25 were partitioned using the partition plate 23 of the cylinder tube 20 and a separate object, the both end surfaces of a peripheral material The first piston chamber 24 and the second piston chamber 25 may be removed and formed, and the intermediate wall may be integrally provided with the cylinder tube 20.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing of the vacuum valve which concerns on embodiment of this invention, and shows the valve closed state when the stroke adjustment member is arrange | positioned in the lowest point position.

FIG. 2 is a sectional view of the vacuum valve shown in FIG. 1 and shows a slow exhaust state when the stroke adjusting member is disposed at the lowest point position.

FIG. 3 is a cross-sectional view of the vacuum valve shown in FIG. 1 and shows a rapid exhaust state when the stroke adjusting member is disposed at the lowest point position.

4 is a top view of the vacuum valve shown in FIG. 1.

FIG. 5 is a view for explaining a method in which the stroke adjusting member of the vacuum valve element shown in FIG. 1 is positioned at the origin position. FIG.

It is a figure which shows the modification of the vacuum valve of this invention.

7 is a sectional view of a conventional vacuum valve, and shows a valve closed state.

FIG. 8 is a cross-sectional view of the vacuum valve shown in FIG. 7 and shows a slow exhaust state.

9 is a cross-sectional view of the vacuum valve shown in FIG. 7 and shows a rapid exhaust state.

[Description of the code]

1, 1A vacuum valve 3 pump port

4 chamber port 6 valve seat

7 valve element 10 annular sealing member

11 spindle 11d adjustment thread

20 cylinder tubes 21 bottom lid

22 Top lid 22a through hole

23 Partition plate (middle wall) 24 First piston seal

25 2nd piston seal 26 1st piston

27 2nd piston 38 Stroke adjustment member

39 Fixing screw (fixing member) 45 Fixing screw (fixing member)

Claims (4)

By elastically deforming and closely contacting the annular sealing member mounted to the valve element to the valve seat of the body provided between the chamber port and the pump port, the chamber port and the pump port are blocked between the first piston and the second port. The piston is slidably arranged in the first piston chamber and the second piston chamber installed in the cylinder tube, such that a main shaft connected to the valve element is fixedly mounted to the first piston and inserted into the second piston so that the second piston is A vacuum valve element having a catching member for adjusting the stroke of said valve element by operating said first and said second piston separately, The main shaft is formed with an adjustment screw portion on the outer peripheral surface of the portion to be inserted into the second piston seal, The locking member is a stroke adjusting member screwed to the adjusting screw portion, And a fixing member for fixing the stroke adjusting member to the main shaft. The method of claim 1, The cylinder tube, A cylindrical shape is opened at both ends, and the inner space is divided by an intermediate wall. Install a bottom lid in one opening and form the first piston seal, Install the upper lid in the other opening and form the second piston seal, The upper lid is formed with a through-hole for inserting the main shaft screwed to the stroke adjustment member. The method according to claim 1 or 2, And the second piston is in surface contact with the upper lid. The method according to claim 1 or 2, And the screw diameter of the adjusting screw portion is smaller than the diameter of the main shaft.

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