KR100987466B1 - Vacuum opening/closing valve - Google Patents

Abstract

A circumferential surface of a piston in a vacuum opening and closing valve which is connected between a vacuum container and a vacuum pump and controls the vacuum pressure in the vacuum container by changing the opening degree of the O-ring as a valve element with respect to the valve seat. And a vacuum opening / closing valve which seals a predetermined distance from the inner peripheral surface of the cylinder with a bellofram following the operation of the piston, and opens and closes the piston by a fluid. Formed with an inclination angle, the outer periphery of the piston being formed with a predetermined inclination angle, the inner circumference of the bellofram contacting the piston when the valve element is in contact with the valve seat and the outer periphery of the piston Same diameter

Description

Vacuum opening and closing valve {VACUUM OPENING / CLOSING VALVE}

The present invention relates to a vacuum opening and closing valve. In particular, the present invention relates to a vacuum valve which is connectable between the vacuum vessel and the vacuum pump and controls the vacuum pressure of the gas in the vacuum vessel by changing the valve opening degree.

Background Art Conventionally, for example, in a semiconductor manufacturing process, a vacuum pressure control system or the like for alternately supplying and discharging a process gas and a purge gas into a vacuum chamber in which a wafer is arranged has been proposed. In such a vacuum pressure control system, a vacuum opening and closing valve is connected between the vacuum chamber and the vacuum pump. This vacuum open / close valve changes the opening degree and controls the vacuum pressure of the process gas supplied into the vacuum chamber (refer Unexamined-Japanese-Patent No. 09-072458).

A conventional vacuum opening / closing valve will be briefly described with reference to FIGS. 11 to 16. 11 is a cross-sectional view showing a vacuum opening and closing valve 100 included in the vacuum pressure control system of Japanese Patent Application Laid-Open No. 09-072458 proposed by the present applicant. FIG. 12 is an enlarged view of an R portion in FIG. 11 and is an explanatory view for explaining the form of a bellofram 150 in a valve closed state. 13 is a cross-sectional view illustrating a conventional bellofram 150. FIG. 14 is an explanatory view for explaining the texture of bubbles in a conventional bellofram 150.

In the vacuum open / close valve 100, when the driving air is supplied into the air receiving chamber AS and the piston 140 is raised (upward in FIG. 11), the poppet valve is connected to the piston 140 through the piston rod 147. A poppet valve element 176 rises in the stroke direction of the piston 140 and the poppet valve element 176 falls off the valve seat 173 so that the valve opens. The piston 140 is coupled with the cylinder 130 in a single-acting pneumatic cylinder 130 (hereinafter referred to as "cylinder 130") to prevent the occurrence of stick-slips. Drive in a non-contact state. The gap 145 between the piston 140 and the cylinder 130 is closed by a bellofram 150 that follows with the operation of the piston 140. Thus, airtightness in the air storage chamber AS is ensured.

As shown in FIG. 13, the bellofram 150 has a trapezoidal cross-sectional shape when viewed from the bore (or radius) direction of the piston 140. A bellofram 150 is formed by embedding a bubble 151B such as polyester in rubber by insert molding. As shown in FIG. 14, this bubble 151B has the mesh of the plain weave which crossed the thread | lattice one by one in the longitudinal direction and the transverse direction respectively. The bellofram 150 fixes the central portion 152 to the hydraulic pressure surface 142 of the piston 140 and fixes the flange portion 153 to the flange holding portion 132 of the cylinder 130. Of these ballast rams 150, an annular single-taperd surface 154 that folds deep in the flange portion 153 and extends toward the central portion 152 is an imaginary line N along the axis AX. ) Is a single inclined surface with an angle of short taper angle θp.

In addition, the following reason is mentioned as a reason to employ | adopt the shape of the conventional bellofram 150 about trapezoidal.

(a) In the vacuum opening / closing valve 100 having a bellofram 150, the piston outer diameter dp of the outer circumferential surface of the piston 140 has a predetermined interval 145 of the cylinder 130. It is smaller than the inner diameter, and the short tapered surface 154 of the bellows ram 150 may increase with the driving of the piston 140 to the position of the top dead center of the piston 140.

(b) In the vacuum open / close valve 100, when the valve is opened, the central portion 152 and the flange portion 153 of the bellofram 150 are positioned at substantially the same height, as shown in FIGS. 11 and 12. The end tapered surface 154 is folded in a mount-folded shape within the gap 145 between the piston 140 and the cylinder 130.

This is to make the end tapered surface 154 into a single inclined surface inclined at a predetermined end taper angle θp with respect to the axis AX along the stroke direction of the piston 140, that is, the imaginary line N, A bellofram 150 is easily stretched in accordance with the opening and closing operation of the vacuum open / close valve 100.

On the other hand, with respect to a vacuum opening valve driven by a bellofram, it is disclosed in Fig. 1 of Japanese Patent Laid-Open No. 2002-132354 and Figs. 2, 5 and 6 of Japanese Patent Laid-Open No. 07-150623. have. In addition, as for the thing provided with the inclined surface from which the angle of a bellofram differs, FIG. 1 and FIG. 4 of Unexamined-Japanese-Patent No. 56-049462, FIG. 3 of Unexamined-Japanese-Patent No. 61-140296, and Japan Unexamined 1 and 5 of Utility Model No. 61-172230.

In addition, it is disclosed in Japanese Patent Laid-Open No. 10-317262 and Japanese Patent Laid-Open No. 10-132077 for forming a valve pram by insert molding bubbles of tricot weave.

However, the vacuum opening and closing valve 100 has the following problems.

(1) FIGS. 11 and 12 are positions in which the vacuum opening / closing valve is closed. In this state, when the driving air is supplied to the air receiving chamber AS, the pressing force by the driving air is applied to the central portion 152 of the bellofram 150 and the gap 145 between the piston 140 and the cylinder 130. It is applied to the folded end-taper surface 154 of the, to raise the piston (140).

At this time, the short-taper surface 154 is supplied by the driving air into the air receiving chamber AS, so that a part of the short tapered surface 154 is in contact with the outer circumferential surface of the piston 140 in the folded form shown in FIG. It expands toward the inner circumferential surface of the cylinder 130 (see FIG. 15).

The bellofram 150 is approximately trapezoidal in shape, and because the end-tapered surface 154 is radially outward of the axis AX than the outer circumferential surface of the piston 140, the axis of the bellofram 150 In the same position as the (AX) direction, the tapered surface diameter length Dp of the surface contacting the piston 140 of the bellowram 150 in the radial direction at this position is represented by a dashed-dotted line in FIG. It is larger than the outer peripheral diameter dp. Although the bellofram 150 has a tapered surface, the piston 140 is cylindrical in shape, so the shortest diameter of the bellofram 150 must be determined along the diameter of the piston 140. The difference between πDp and πdp in FIG. 12 is increased.

That is, since the length (short-peripheral surface peripheral length) π Dp in the peripheral direction of the short-taper surface 154 is larger than the length (peripheral length of the outer peripheral surface of the piston) π dp of the outer peripheral surface of the piston 140, the bellofram In part of 150, a portion that does not contact the outer circumferential surface of the piston 140 will form a wrinkle generation portion 159.

As the peripheral length difference between the periphery length? Dp of the tapered surface and the periphery length? Dp of the outer peripheral surface of the piston becomes larger, the wrinkle generation portion 159 becomes larger. In addition, the pressing force applied along the end-taper surface 154 of the bellofram 150 toward the outer circumferential surface of the piston 140 is applied to the end-taper surface 154 and the piston 140 of the corrugation part 159. It is greater than the pressure in the inner space between the outer peripheral surface.

For this reason, when the pressing force is applied along the end-taper surface 154 in the wrinkle generation part 159, the part of the end-taper surface 154 is pressed in contact with or close to each other by the pressing force, and the piston 140 Protrude toward the radially outer side of the piston 140 in the vicinity of the outer peripheral surface. Thus, each protruding portion is folded deeply at the outermost bent portion 159B in the radial direction. When the short tapered surface 154 is protruded toward the outermost side in the radial direction, the bent tapered surface 154 is inclined at an acute angle at the bent portion 159B of the generated wrinkled portion 159. May occur, and excessive bending stress may be applied to the bending portion 159B.

As shown in FIG. 16, when the piston 140 shown in FIG. 15 is raised in a state where the bent portion 159B is formed, the cylinder 130 is positioned on the side where the bent portion 159B contacts the piston 140. Move toward the inner wall of the contact. The bent portion 159B is shifted in the 180 degree direction by this movement. Since the bent portion 159B has a sufficiently large inner diameter of the inner wall surface on the inner wall surface side of the cylinder 130, the bent portion 159B eliminates the bending. However, when the curved portion 159B is switched in the 180 degree direction, the curved portion 159B is subjected to concentrated stress. Each time the vacuum shut-off valve is driven, this concentrated stress is repeatedly received, causing longitudinal bellows cracks in the bellofram 150.

Applicant sells the vacuum opening and closing valve according to the present invention all over the world, but was unable to identify the cause of the problem regarding the durability of the bellofram 150. Applicant finally found the cause through repeated experiments.

(2) Moreover, the bubble of the bellofram 150 is formed by the mesh of the plain weave shown in FIG. 14, and the flexibility of the mesh direction is low, and the bellofram 150 itself is difficult to bend freely. Thus, the crease 159 is present locally with relatively large creases over the periphery of the short-tapered surface 154 upon supply of drive air (see FIG. 16). Then, when the valve is closed, bubbles of the short-tapered surface 154 folded in the wrinkle generating portion 159 rub against each other, and cracks at the top portion 158 grow over time to the wrinkle generating portion 159. , Bubbles of the bellofram 150 are broken.

By the problems of (1) and (2), the driving air supplied into the air receiving chamber AS leaks through the bellofram 150, and the opening degree of the vacuum opening / closing valve 100 can be controlled. There was a problem of disappearing. For this reason, the bellofram 150 has to be replaced frequently, and a durable vacuum opening and closing valve has been called for.

The present invention has been made to solve such a problem, and the vacuum opening and closing to seal the gap between the outer peripheral surface of the piston and the inner peripheral surface of the cylinder with a bellofram following the operation of the piston, and to open and close the piston by driving the fluid An object of the valve is to provide a durable vacuum opening / closing valve.

(1) In order to achieve the object of the present invention, there is provided a vacuum opening and closing valve connectable between a vacuum container and a vacuum pump. The valve is a valve seat having a port connectable to one of the vacuum vessel or the vacuum pump, a valve element that can come into contact with and fall off the valve seat, a piston that is driven by a fluid and moves the valve element. And a cylinder for receiving the piston and a bellofram for deforming and sealing a predetermined distance between the outer circumferential surface of the piston and the inner circumferential surface of the cylinder along with the operation of the piston. A vacuum open / close valve is arranged to control the vacuum pressure in the vacuum container by varying the opening degree of the valve element with respect to the valve seat. In the vacuum opening / closing valve, a bellofram includes a peripheral surface formed at a predetermined inclination angle at the same time as contacting the outer peripheral surface of the piston, the outer peripheral surface of the piston including an inclined surface formed at a predetermined inclination angle, The bellofram and the piston have an inner circumference of a portion of the peripheral surface that contacts the piston of the bellofram when the valve element is in contact with the valve seat. The outer circumference of the piston in contact with the bellofram is configured to be the same, the inclination angle of the bellofram is configured to be equal to the inclination angle of the piston, and a peripheral surface of the bellofram (peripheral surface) is a cross section along the central axis, the first angle is different from the axis along the stroke direction of the piston, Including two inclined surfaces, and the angle of inclination of the bellows diaphragm (bellofram) is of the first and second inclined surfaces, the inclination angle of the small angle inclined FIG. The vacuum opening and closing valve further includes a rod connecting the valve element and the piston, wherein the bellofram includes an insertion hole into which the rod is inserted and the bellofram passes through the insertion hole. Positioning is performed by fitting with the outer periphery of.

(2) In the vacuum opening / closing valve of (1), preferably, the bellofram includes a fixing part fixed to the cylinder at a radial periphery, and the bellofram is formed in the first and second parts. And an inflection portion connecting the two inclined surfaces, wherein the inflection portion is located toward the fixing portion rather than the axial center position of the bellofram.

(3) In the vacuum opening / closing valve of (1), preferably, the bellofram is made of a rubber molding member embedded with rubber by insert molding, and the bubble is the bellofram. It has a flexible texture in the direction along the central axis of.

(4) In the vacuum opening and closing valve of (3), preferably, the texture of the bubble is a tricot weave.

The vacuum opening / closing valve of the present invention described in (1) is connected between the vacuum container and the vacuum pump, and the vacuum opening / closing which controls the vacuum pressure in the vacuum container by changing the opening degree of the valve element with respect to the valve seat. A valve is a vacuum opening / closing valve which seals a predetermined distance between the outer circumferential surface of the piston and the inner circumferential surface of the cylinder with a bellofram that follows the operation of the piston and drives the piston to open and close by a fluid.The piston of the bellofram The inner circumferential surface in contact with the piston is formed at a predetermined inclination angle, and the outer circumferential surface of the piston is formed at the predetermined inclination angle, and when the valve element is in a position in contact with the valve seat, When the outside diameter of the piston is the same, when the driving air enters the cylinder with the vacuum closing valve closed, and air pressure is applied to the Since the inner circumferential diameter of the bellows ram and the outer circumferential diameter of the piston are the same, no bending occurs in the bellofram.

In the related art, since the piston has a cylindrical shape, the inner circumferential diameter in contact with the piston of the bellofram at a position corresponding to the piston cross section has to be larger than the outer circumferential diameter of the piston. In the present invention, by providing the inclined surface on the outer circumference of the piston, the bellowram inner circumferential diameter and the piston outer circumferential diameter can be the same length at the position where the vacuum opening / closing valve is first closed.

In addition, in the vacuum opening / closing valve of the present invention described in (1), the inclination angle of the bellofram and the inclination angle of the piston are the same, so that when the piston moves at a certain distance, the bellofram remains in that state. In order for the inner circumference and the outer circumference of the piston to be the same, there is no case where the bellofram is bent. Even if the inclination angle of the bellofram is slightly larger than the inclination angle of the piston, when the valve element is in contact with the valve seat, the inner circumference of the bellofram and the outer circumference of the piston are in contact with the piston. If it is the same, the applicant has confirmed by experiment that the durability of the bellofram is remarkably improved. Applicants have confirmed by experiment that the inclination angle of the bellofram and the inclination angle of the piston are the same to further improve durability.

In the vacuum opening / closing valve of the present invention as described in (1), the bellofram has at least two tapered surfaces having different angles from the axis along the stroke direction of the piston in the cross-sectional shape as seen in the bore direction of the piston. In the case of having two tapered surfaces, the first taper angle θ1 is a single short taper angle θp of a conventional bellofram with respect to the angle. By making it larger than ((theta) p <(theta) 1), it can be made smaller than 2nd taper angle (theta) 2 ((theta) 2 <(theta) p).

In this case, the first tapered surface inclined at the first taper angle θ1 with respect to the axis line toward the inner peripheral surface of the cylinder, and the second tapered surface inclined at the second taper angle θ2 with respect to the axis line toward the outer peripheral surface of the piston, By forming a bellofram in the shape in which each is located, in particular, the inclination angle of the second tapered surface of the bellofram can be made equal to the inclination angle of the tapered surface of the outer circumferential surface of the piston.

Therefore, the bellofram has at least two tapered surfaces having different angles, so that the bellofram can maintain elasticity due to the opening and closing operation of the vacuum opening / closing valve, and at the same time, the bellofram is caused by cracks caused by wrinkles. The damage in the short term can be suppressed.

Further, in the vacuum opening / closing valve described in (1), by inserting the bellofram with the outer periphery of the rod connecting the valve element and the piston, an insertion hole for positioning the bellofram is provided. Equipped.

This makes it possible to accurately position the piston and the bellofram through the rod.

However, when the vacuum opening / closing valve is opened or closed, when the tapered surface of the bellofram is folded in a folded shape, the tapered surface is located at the top dead center or bottom dead center of the piston according to the driving of the piston. It is located near the center of the stroke direction in the extended state.

In the vacuum opening / closing valve of the present invention as described in (2), since the inflection portion connecting the tapered surfaces is located toward the fixed portion rather than the position in the axial center of the bellofram, the tapered surface of the bellofram Even when folded in a folded form, it is not folded in the inflection section.

Even if the vacuum opening / closing valve is repeatedly opened and closed, the bellowram due to repeated folding in the inflection section is not repeatedly folded in the inflection section where the stress is more likely to concentrate than other portions of the tapered surface of the bellofram. The occurrence of deterioration of the bellofram (fatigue of the material constituting the bellofram) can be prevented.

Therefore, the bellofram can be prevented from being damaged prematurely.

Further, in the vacuum opening and closing valve of the present invention as described in (3), the bellofram is a rubber molded article in which a foam having a textured texture is inserted into a direction along the plane of the bellofram with rubber. do.

As a result, the bellofram can obtain the strength against the sealing force due to the rubber and the pressing force of the fluid due to the bubble. Therefore, the bellowram is easily bent freely in response to the operation of the piston and the shape of the piston.

In addition, in the vacuum opening / closing valve of the present invention as described in (4), since the texture of the bubbles of the bellofram is a tricot weave, the bellofram at the time of pressurization of the fluid causes the operation of the piston and It becomes easy to bend freely according to the shape of a piston.

In particular, in the vacuum opening / closing valve of the present invention, when the tapered surface of the bellofram expands toward the outer circumferential surface of the piston when the fluid is pressurized, the bellofram easily bends freely to follow the shape of the outer circumferential surface of the piston. .

For this reason, at the arbitrary position of the stroke direction of a piston in the bellofram of the vacuum opening / closing valve of this invention, a taper surface is made by the difference between the length of the peripheral direction of a taper surface, and the length of the peripheral direction of the outer peripheral surface of a piston. The wrinkles which occur can be made small compared with the bellofram of the conventional vacuum switching valve. In addition, these wrinkles do not have relatively large wrinkles locally on the periphery of the short-taper face of the bellofram, such as the bellofram of a conventional vacuum open / close valve, and in the conventional bellofram It becomes smaller than the wrinkles which generate | occur | produced, and is scattered on the periphery of a taper surface. For this reason, when opening or closing the said vacuum opening / closing valve, it becomes easy to avoid the contact between the folded tapered surface in the part which becomes a wrinkle, and it can suppress that a friction generate | occur | produces between bubbles.

Therefore, even if a crack occurs in the folded portion of the tapered surface, breakage of the bellofram due to friction between bubbles of the folded tapered surface can be suppressed by the growth of the crack.

In addition, a tricot weave is, for example, a ribbed weave, which is a texture of a yarn in which a ridge and a curved portion are alternately arranged in a predetermined direction, such as a ridge, It is a weaving method of the same type as the texture of the mattress, and the weaving method of the fabric having flexibility, elasticity and elasticity.

In addition, in the vacuum opening and closing valve of the present invention described above, a bellofram includes a convex portion protruding in the thickness direction at a central portion thereof in the radial direction, and the piston includes a concave portion concave on the hydraulic pressure surface in the bore direction. The bellofram and the piston are fitted with convex and recessed portions, which are positioned and fixed on the concentric shaft.

As a result, there is no relative positional shift between the radial center portion of the bellofram and the hydraulic pressure surface of the piston, so that the tapered surface of the bellofram bends evenly in the peripheral direction of the tapered surface in accordance with the operation of the piston. Can grow or stretch. Therefore, the piston can be properly driven.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment which actualized the vacuum opening / closing valve which concerns on this invention is described in detail based on drawing. 10 is a schematic diagram showing the configuration of the vacuum pressure control system 1 including the vacuum opening and closing valve 10.

The vacuum pressure control system 1 is a pressure control system for supplying and discharging process gas and purge gas into the vacuum chamber 2 in which the wafer 8 is disposed in the surface treatment of the wafer 8 in a semiconductor manufacturing process. . As shown in Fig. 10, this vacuum pressure control system 1 comprises a vacuum chamber 2 (vacuum container), a vacuum pump 5, an air source 6 for supplying driving air AR, and a vacuum opening / closing valve ( 10), a servovalve (not shown) for controlling the valve opening degree VL of the vacuum open / close valve 10, and a vacuum pressure control device 7 for electrically connecting the vacuum open / close valve 10 and the like.

The gas supply port 2a of the vacuum chamber 2 is used to purge the supply source of the process gas used for surface treatment of the wafer 8 disposed in the vacuum chamber 2 and the process gas in the vacuum chamber 2. It is connected in parallel with the supply source of nitrogen gas to be used.

On the other hand, the gas discharge port 2b of the vacuum chamber 2 is connected in parallel with the chamber pressure sensor 3 via the vacuum opening / closing valve 10 and the shutoff valve 4. The chamber pressure sensor 3 is electrically connected to the vacuum pressure control device 7 and measures the vacuum pressure of the process gas or the like in the vacuum chamber 2. The vacuum open / close valve 10 is also connected to the vacuum pump 5.

The vacuum open / close valve 10 will be described with reference to FIGS. 1 to 6.

FIG. 1: is explanatory drawing in sectional view when the bellofram 50 contained in the vacuum pressure valve 10 of this embodiment is seen from the bore direction BR of the piston 40. As shown in FIG. FIG. 2 is an explanatory view for explaining the configuration of the rubber molding member 51 constituting the bellofram 50. In FIG. FIG. 3: is explanatory drawing explaining the texture of the bubble 51B among the rubber molding members 51 shown in FIG. 4 is an explanatory diagram for explaining the configuration of the vacuum opening / closing valve 10, and showing a valve closing state. FIG. 5 is a view showing a valve open state of the vacuum open / close valve 10 shown in FIG. 1, and FIG. 6 is an enlarged view of the P portion of FIG. 4.

The vacuum opening / closing valve 10 of the present embodiment changes the valve opening degree VL by the drive air AR which passes through a servo valve not shown in the air supply source 6 and is supplied into the air storage chamber AS. It is used as a vacuum opening / closing valve for controlling the vacuum pressure of the process gas or the like in the vacuum chamber 2.

This vacuum opening / closing valve 10 has a valve opening side (Fig. 4 and Fig. 5) in the direction of its axis AX, that is, the valve shift direction (up and down directions in Figs. Pilot cylinder section 20 located in the upper part in FIGS. 4 and 5 and a bellows-type poppet valve located in the valve closing side (lower part in FIGS. 4 and 5). section 70).

The pilot cylinder portion 20 includes a single-acting pneumatic cylinder 30, a cylinder holding portion 32, an air receiving chamber AS, a piston 40, a return spring 47 and a bellofram; 50) and the like.

In the vacuum open / close valve 10, when the drive air AR is supplied to the air storage chamber AS, the piston 40 is in contact with the inner circumferential surface 31 of the cylinder in the single-acting pneumatic cylinder 30, and the axis AX It is made to drive in the stroke direction ST which follows () direction. The piston outer circumference dp of the outer circumferential surface 41 of the piston 40 is smaller by a predetermined size than the diameter of the cylinder inner circumferential surface 31 of the single-acting pneumatic cylinder 30. An annular recess 44 is provided on the hydraulic pressure surface 43 of the piston 40 in the stroke direction ST. The predetermined interval 45 between the outer circumferential surface 41 of the piston 40 and the cylinder inner circumferential surface 31 of the single-acting pneumatic cylinder 30 is later described in detail with a bellofram shown in FIG. It is sealed by 50), and the airtightness in air storage chamber AS is ensured.

In addition, since the piston 40 is driven in a non-contact state with the cylinder inner circumferential surface 31 of the single-acting pneumatic cylinder 30, stick-slip of the piston 40 does not occur, and the piston 40 has a high response and accurate position. The single acting pneumatic cylinder 30 can be driven with accuracy.

The piston 40 is biased toward the valve closing direction in the valve shift direction by the return spring 47. When the drive air AR is not supplied to the air accommodating chamber AS, the piston 40 is located at the lower point by the biasing force by the return spring 47 (see Fig. 4). On the other hand, when drive air AR is supplied to air storage chamber AS, piston 40 will move to the valve opening direction of a valve shift direction against the force applied by return spring 47 (refer FIG. 5). ).

In addition, when the piston 40 moves in the valve shift direction in the vacuum opening / closing valve 10, the displacement amount of the piston 40, i.e., vacuum opening and closing, as much as the piston 40 is displaced toward the top dead center from the position of the lower dead point. The displacement sensor 81 which measures the valve opening degree VL of the valve 10 in a non-contact state is provided (refer FIG. 4 and FIG. 5). The displacement sensor 81 is electrically connected to the vacuum pressure control device 7.

The bellofram 50 is a bellofram made of a rubber molding member 51 in which a foam 51B having a texture of tricot weave is inserted into the rubber 51A (Fig. 1 and Fig. 1). 2). In addition, a tricot weave is a ribbed woven fabric which is a texture of a yarn in which the ridges and the curved portions are alternately arranged continuously in a predetermined direction as shown in FIG. 3, for example. It is a weaving method in the form of a weave or a texture of kneading, and it is a weaving method that gives the fabric flexibility, elasticity and elasticity.

When the driving air AR is supplied into the air accommodating chamber AS, the bellofram 50 may be stretched to keep the effective hydraulic pressure area of the hydraulic pressure surface 43 of the piston 40 constant. Since the bellofram 50 is made of a rubber molding member 51, the airtightness of the bellowram 50 against the pressing force by the driving air AR supplied to the air accommodating chamber AS is airtight. Is given to the rubber 51A, respectively. As the rubber 51A used for the rubber molding member 51, for example, natural rubber, acrylonitrile-butadiene rubber, styrene-butadiene rubber, butadiene rubber (butadiene rubber), isoprene subber, propylene-butadiene rubber, acrylonitrile-isoprene rubber, chloroprene rubber, isobutylene-isoprene rubber isobutylene-isoprene rubber (butyl rubber), ethylene propylene subber, acrylic rubber, fluorocarbon rubber, ether-thioether rubber And synthetic rubbers such as polysulfide rubber, urethane rubber, and silicone rubber. In addition, as a material for the bubble 51B, for example, a yarn such as polyamide (Nylon 6, nylon 66, etc.), aramid, polyester, or cotton may be selected. It can be woven to have flexibility in the direction along the surfaces 51a and 51b of the bellofram 50 (rubber forming member 51).

As shown in FIG. 1, the bellofram 50 is a piston in the cross-sectional view as seen in the bore direction BR (left and right directions in FIGS. 4 and 5) of the piston 40 in this embodiment. Two first taper surfaces 55A and second taper surfaces 55B having different angles from the axis AX along the stroke direction ST (up and down directions in FIGS. 4 and 5) of the 40 are provided. Doing. The bellofram 50 also has an annular flange portion 54 (fixed portion) located at the outer periphery of the radial direction (bore direction BR of the piston 40) and the flange portion 54. It further includes the center part 52 (diameter direction center part) located in the radial center center between the 1st, 2nd taper surface 55A, 55B.

The first tapered surface 55A has an angle of inclination with the imaginary line M parallel to the axis AX in the inclined surface that is folded than the inclined upper portion 54S in the radial direction of the flange portion 54. It is an annular inclined surface of (0 <θ1 <90 °). The 2nd taper surface 55B is an annular inclined surface which makes the angle | corner with this imaginary line M into 2nd inclination angle (theta) 2 (0 <(theta) <2). The first taper surface 55A and the second taper surface 55B are continuously connected to the inflection portion 56, and the inflection portion 56 is formed in the ballast ram 50 in the state shown in FIG. It is located in the flange part 54 side rather than the center position of the axis line AX direction. The reason why the inflection portion 56 is in such a position is that when the vacuum opening / closing valve 10 is closed, the second tapered surface 55B of the bellofram 50 has the piston 40 at the top dead center. When it moves to a position and with this movement, the 2nd taper surface 55B is extended to the position of the top dead center of a piston, it is folded in the folded form at the position near the center of stroke direction ST.

In addition, the center portion 52 is continuously connected to the second tapered surface 55B in the direction along the bore direction BR (left and right directions in FIGS. 4 and 5) of the piston 40. The central portion 52 has a through hole 57 for inserting the piston rod 48 to be described later, and the convex portion 53 protruding in the thickness direction (up and down direction in FIG. 1) of the central portion 52 is provided. The periphery of the through hole 57 is formed in an annular shape. The size of the through hole 57 is formed with high accuracy to fit with the outer circumference of the piston rod 48.

As shown in FIG. 6, the bellofram 50 is positioned at the piston 40 by inserting the convex portion 53 into the recess 44 of the piston 40. The bellofram 50 has the central portion 52 in contact with the hydraulic pressure surface 43 of the piston 40, and the central portion 52 is connected to the piston 40 and the plate-shaped fastener 46. It is inserted between and, and it is fixed by screwing the piston 40 and the fixture 46 to it.

In addition, the flange portion 54 of this bellofram 50 is inserted into and fixed to the single-acting pneumatic cylinder 30 and the flange holding portion 32.

Flange of the bellofram 50 when the piston 40 is at the bottom dead center position of the vacuum opening / closing valve 10, that is, when the driving air AR is not supplied to the air receiving chamber AS. 54 and the center part 52 become substantially the same position as the stroke direction ST (refer FIG. 4). Then, as shown in FIGS. 4, 6 and 7, the second tapered surface 55B is folded in a folded shape at the top portion 58 at the interval 45 between the piston 40 and the cylinder 30. All.

On the other hand, when the drive air AR is supplied to the air storage chamber AS, as shown in FIGS. 6 and 7, the second tapered surface 55B is folded in the top portion 58 and is shown in FIG. 7. As shown by the two-dot broken line, the cylinder expands along the inner circumferential surface 31 of the single-acting pneumatic cylinder 30 and the outer circumferential surface 41 of the piston 40, and then the top dead center of the piston 40 in the stroke direction ST. It extends toward (above, FIG. 6 and FIG. 7), and extends to the state shown in FIG.

As described above, the bellofram 50 is the first in a state in which the flange portion 54 is fixed to the flange holding portion 32 and the center portion 52 is fixed to the hydraulic pressure surface 43 of the piston 40, respectively. The second tapered surfaces 55A and 55B are positioned at the gap 45 between the piston 40 and the cylinder 30, and the gaps 45 are folded or stretched in accordance with the driving of the piston 40. It is sealed.

FIG. 6 is an enlarged view of a portion P of FIG. 4, and FIG. 4 shows a valve closed state in which the O-ring 79 is completely in contact with a valve seat. 6 shows the shape of the bellofram 50 in the valve closed state.

In the valve closing state in which the O-ring 79 is completely in contact with the valve seat 73, when the driving air AR is supplied, the bellofram 50 is shown by the two-dot chain line in FIG. Position, and the point where the bellofram 50 contacts the piston 40 changes slightly. In the present invention, the position in which the ball valve 50 is in contact with the piston 40 (the position indicated by the height L1, that is, the bellofram 50 shown by the two-dot chain line in FIG. 7) is in contact with the piston 40. The inner circumference of the bellofram 50 of the upper position) is W2.

On the other hand, sectional drawing of the piston 40 is shown in FIG. The external shape of the piston 40 forms the piston taper surface 40a which becomes thinner toward the end which the front end part has an angle of (theta). This angle θ is equal to the second taper angle θ2 of the bellofram 50. The piston taper surface 40a is provided in the lower half of the piston 40. The upper half does not contact the bellofram 50 so it does not need to taper to the end.

That is, W1 is in the valve closed state where the O-ring 97 is in contact with the valve seat 73, so that the outer circumference of the piston is in contact with the bellofram 50 when the driving air AR is supplied. The outer diameter of the piston at the upper end.

W2 has a bellofram 50 in contact with the piston 40 when the O-ring 97 is in the valve closed state in contact with the valve seat 73 and the driving air AR is supplied. Inner circumference in contact with the piston 40 of the bellofram 50 at the top.

As shown in FIG. 7, the outer peripheral diameter of the piston 40 at the position of the distance of L1 from the piston tip is set to W1. The distance L1 from the piston tip is the upper position where the bellofram 50 is in contact with the piston 40 in the bellofram 50 shown by the dashed two-dot line in FIG.

Here, in the valve closing state shown in FIG. 4, W2 of the valve | ramp ram 50 and W1 of the piston 40 are made the same length.

Next, the bellows type poppet valve part 70 is demonstrated.

This bellows type poppet valve part 70 includes a valve body 71, a bellows 75, a poppet valve element 76, an O-ring holding member 77, an O-ring 79, and the like.

The piston rod 48 is connected to the radially center portion of the piston 40, and is sealed with an O-ring 49 between the piston rod 48 and the piston 40. The piston rod 48 extends toward the bellows type poppet valve portion 70 and is connected to the poppet valve element 76 at the valve open end of the piston rod 48, the poppet valve element 76 being a piston rod. Accompanying the drive of the stroke direction ST of 40, it moves so that it may move in the valve shift direction with the piston 40. FIG. The bellows 75 fixes an end portion at one end side (upper side in FIGS. 4 and 5) in the axis AX direction, and installs the other end portion at the poppet valve element 76 to provide a diameter of the piston rod 48. It is provided so that it may expand and contract with the drive of the valve shift direction of the poppet valve element 76 in the form which covers a direction outer side.

The O-ring holding member 77 of the poppet valve element 76 is fixed on the valve closing side (downward in FIGS. 4 and 5) of the poppet valve element 76, and the poppet valve element 76 and the O-ring holding member An annular O-ring attachment portion 78 formed by 77 is provided. The O-ring 79 is disposed in the O-ring attachment portion 78 and is in contact with a valve seat 73 of the valve body 71. The valve body 71 includes a first port 72 connected to the vacuum pump 5 and a second port 74 connected to the gas discharge port 2b of the vacuum chamber 2.

When the driving air AR is not supplied to the air accommodating chamber AS in the vacuum opening / closing valve 10, the piston 40 is located at the bottom dead center by the force applied by the return spring 47, so that the piston ( Poppet valve element 76, which connects to 40, presses valve seat 73 using O-ring 79. This closes the first port 72 with the poppet valve element 76 and closes the vacuum open / close valve 10 (valve opening VL = 0).

On the other hand, when the drive air AR is supplied to the air storage chamber AS, the piston 40 moves in the direction of opening the valve in the valve shift direction against the force applied by the return spring 47, so that the O-ring ( 79, poppet valve element 76 also moves toward the valve opening and falls off the valve seat 73. As a result, the vacuum opening / closing valve 10 is opened (valve opening degree VL> 0), and the first port 72 and the second port 74 communicate with each other. When the vacuum open / close valve 10 is opened, the vacuum pump 5 can suck the process gas or nitrogen gas in the vacuum chamber 2.

In the vacuum opening / closing valve 10 of the present embodiment, the bellofram 50 has a cross-sectional shape as seen in the bore direction BR of the piston 40, and the angle formed by the axis AX is the first inclination angle ( It is a shape provided with 55 A of 1st taper surfaces which are (theta) 1, and 2nd taper surface 55B which is 2nd inclination angle (theta) 2.

Here, the first and second inclination angles θ1 and θ2 between the imaginary line M along the axis AX of the bellofram 50 and the first and second tapered surfaces 55A and 55B. The bellofram 50 of the vacuum open / close valve 10 of the present embodiment is compared with the bellofram 150 of the conventional vacuum open / close valve 100.

As described above, the angle between the first tapered surface 55A and the axis AX (virtual line M) in the vacuum opening / closing valve 10 is the first inclination angle θ1 (0 <θ1 <90 °). In addition, since the angle formed between the second tapered surface 55B and the axis AX (virtual line M) is the second inclination angle θ2 (0 <θ2 <θ1), in the second tapered surface 55B, The length of the radial direction of the arbitrary position of the direction along the axis AX is 2nd taper surface diameter length D2, and the length of the circumferential direction of this position becomes 2nd taper peripheral length (pi) D2.

On the other hand, since the end-taper surface 154 of the bellofram 150 is one in the conventional vacuum opening / closing valve 100, the axis of the end-taper surface 154 and the bellofram 150 ( The angle formed by the imaginary line N along AX is the short-taper angle θp (0 <θp <90 °) (see FIG. 13). As a result, in the end tapered surface 154, the length in the radial direction at any position in the stroke direction of the piston is the short tapered surface diameter length Dp, and the length in the peripheral direction of this position is around the short tapered surface. Length? Dp (see FIG. 16).

In the vacuum opening / closing valve 10 of the present embodiment, the first inclination angle θ1 is made larger than the short-taper angle θp (θp <θ1), and the second inclination angle θ2 is the short-taper angle θp. It can be made smaller (θ2 <θp). As a result, with respect to the magnitudes of the first inclination angle θ1, the second inclination angle θ2, and the short-taper angle θp,

θ2 <θp <θ1 Equation (1)

The relationship is established. The bellofram 50 of the vacuum opening / closing valve 10 has a single acting pneumatic pressure on the first tapered surface 55A inclined at a first inclination angle θ1 with respect to the axis AX based on this equation (1). The second tapered surface 55B inclined at the second inclination angle θ2 with respect to the axis AX toward the cylinder inner circumferential surface 31 of the cylinder 30 toward the outer circumferential surface 41 of the piston 40, respectively. It is molded.

On the other hand, the piston taper surface 40a of the piston 40 is formed at the same inclination angle as the second inclined surface 55B of the bellofram 50. As shown in Fig. 7, the bellofram 50 is supplied when the driving air AR is supplied in the valve closing state in which the O-ring 79 is completely in contact with the valve seat 73. It becomes position as shown by dashed line of 7 points. At this time, the bellowram (50) and the upper end in contact with the piston 40, the inner circumference (W2) and the bellofram (50) in contact with the piston 40 of the bellofram (50) Since the outer circumferential diameter W1 of the piston 40 in contact with each other is the same, the bellofram 50 and the piston 40 are in close contact with each other when the driving air AR flows. It is in a state, and bending does not occur at all.

Thereafter, the point where the bellofram 50 contacts the piston 40 changes, but the piston taper surface 40a of the piston 40 is in contact with the second taper surface 55B of the bellofram 50. Since it is formed at the same inclination angle, the bellofram 50 and the piston 40 remain in close contact with each other.

Compared with the wrinkle generation portion 159 generated in the conventional ball valve 150, such wrinkle generation portion 59 does not occur at all, so that stress concentration does not occur when the piston 40 moves, Even if repeated to some extent, a crack does not arise in the moving direction of the piston 40 like the conventional one. Applicants have repeatedly confirmed the test, but it has been confirmed that the crack does not occur at all, even if the experiment is repeated in the past several ten times repeated.

As described above, according to the vacuum opening / closing valve of the present embodiment, the O-ring 79 which is connected between the vacuum vessel 2 and the vacuum pump 5 and is a valve element with respect to the valve seat 73 is provided. A vacuum opening / closing valve (10) for controlling the vacuum pressure in the vacuum container (2) by varying the opening degree of the piston (40), wherein a predetermined distance between the outer circumferential surface of the piston (40) and the inner circumferential surface (31) of the cylinder (30) is provided. Is a vacuum opening / closing valve (10) which is sealed with a bellofram (50) following the operation of the valve and is opened and closed by driving the piston (40) by a fluid, and the bellofram (50) has a predetermined inclination angle ( formed of θ2, of which the outer periphery of the piston 40 is formed at a predetermined angle of inclination θ, and the bellows that contact the piston when the valve element is in contact with the valve seat ( Since the inner circumferential diameter of the bellofram) and the outer circumferential diameter of the piston are the same, When the drive air enters the cylinder with the valve closed, and the air pressure is applied to the bellofram, the bellowram has the same bend as the inner diameter of the bellofram and the outer diameter of the piston. Does not occur.

Since the piston is conventionally cylindrical, the inner circumferential diameter of contacting the piston of the bellofram at the position corresponding to the piston cross section is forced to be larger than the outer circumferential diameter of the piston. In the present invention, by providing an inclined surface on the outer circumference of the piston, the bellowram inner circumferential diameter and the outer circumferential diameter of the piston can be the same length at the position where the vacuum opening / closing valve is closed for the first time.

In addition, since the inclination angle θ2 of the inner circumferential surface in contact with the piston 40 of the bellofram 50 and the inclination angle θ of the piston 40 are equal, the piston 40 has a certain distance. Even when moved, since the inner circumference of the bellofram 50 in contact with the piston 40 and the outer circumference of the piston 40 are the same, no bending occurs in the bellofram 50.

Although the inclination angle θ2 of the bellofram 50 is slightly larger than the inclination angle θ of the piston 40, the O-ring 79, which is a valve element, is in a position in contact with the valve seat 73. When the inner circumference of the bellofram 50 in contact with the piston 40 and the outer circumference of the piston 40 are the same, the durability of the bellofram 50 is remarkably improved. It confirms by experiment. Applicants have confirmed by the experiment that when the inclination angle θ2 of the bellofram 50 and the inclination angle θ of the piston 40 are the same, the durability is further improved.

In addition, since the bellofram 50 includes two of the first taper surface 55A and the second taper surface 55B, elasticity accompanying the opening / closing operation of the vacuum opening / closing valve 10 can be maintained. At the same time, it is possible to prevent the bellofram 50 from being broken in a short time due to a crack generated due to wrinkles.

In addition, the inflection portion 56 connecting the first taper surface 55A and the second taper surface 55B in the vacuum opening / closing valve 10 is smaller than the central position of the axis AX of the bellofram 50. Since it is located on the flange part 54 side, even when the 2nd taper surface 55B of the bellofram 50 is folded in a folded shape, it does not be folded by the inflection part 56. FIG.

Even if the vacuum opening / closing valve 10 is repeatedly opened and closed, a second portion is provided on the inflection portion 56 where stress is less likely to be concentrated than other portions of the first and second tapered surfaces 55A <55B of the bellofram 50. Since the folding of the tapered surface 55B is not repeated, generation of deterioration of the bellofram 50 (material fatigue of the rubber molding member 51) caused by repeated folding in the inflection section 56 is caused. This can be prevented.

Therefore, the bellofram 50 can be prevented from prematurely breaking.

In addition, in the vacuum opening / closing valve 10 of the present embodiment, the piston rod connecting the piston 40 and the poppet valve element 76 holding the O-ring 79 whose bellofram 50 is a valve element ( By fitting with the outer circumference of 48, the bellowram 50 is provided with a through hole 57 for positioning the bellofram 50 with respect to the piston 40, so that the bellofram 50 can be easily and precisely positioned. Positioning is possible at 40.

Further, in the vacuum open / close valve 10, the bellofram 50 is inserted into the rubber 51A in the direction along the surface 51a of the bellofram 50 by the rubber 51A. The rubber molding member 51 which embed | buried the bubble 51B which has the texture of (tricot weave) is included.

As a result, the rubber 51A provides airtightness to the bubble 51B against the pressing force of the drive air AR, and at the same time, the operation of the piston 40 and the outer circumferential surface 41 of the piston 40. According to the shape of the bellowram (bellofram) is easy to bend freely.

In particular, in the vacuum opening / closing valve 10 of the present embodiment, since the texture of the bubbles 51B of the bellofram 50 is a tricot weave, the bellows ram is supplied at the time of supplying the drive air AR. When the second tapered surface 55B of the bellofram 50 expands along the outer circumferential surface 41 of the piston 40, the bellows pem 50 flexes to follow the shape of the outer circumferential surface 41 of the piston 40. Easier

In addition, the bellofram 50 and the piston 40 in the vacuum opening / closing valve 10 are positioned and fixed on the concentric shaft by the insertion of the convex portion 53 and the concave portion 44.

As a result, a relative positional shift between the central portion 52 of the bellows ram 50 and the pressure receiving surface 43 of the piston 40 does not occur, so that the first and second tapered surfaces of the bellofram 50 are not present. The 55A and 55B can be bent or extended evenly in the peripheral direction of the 1st, 2nd taper surface 55A, 55B in accordance with the operation | movement of the piston 40. FIG. For this reason, the piston 40 can be driven appropriately, and the clearance 45 between the outer peripheral surface 41 of the piston 40 and the cylinder inner peripheral surface 31 of the single-acting pneumatic cylinder 30 is a bellofram 50. ) Can be sealed in an appropriate state.

As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to embodiment mentioned above, It is natural that it can change suitably and can apply in the range which does not deviate from the summary.

For example, in the present embodiment, the concave portion 44 of the piston 40 is provided on the hydraulic pressure surface 43, and the convex portion 53 of the valve ram 50 is formed in the center portion 52 in an annular shape. Prepared. However, the concave portion of the piston and the convex portion of the bellofram may be a shape in which both are positioned by insertion of the concave portion of the piston and the convex portion of the bellofram, and the concave portion of the piston is bellofram. The position at which the convex portion is disposed and the shape of the concave portion and the convex portion can be appropriately changed.

Further, in the bellofram 50 in the present embodiment, an annular shape in which the angle between the inclined starting point portion 54S and the inflection portion 56 and the imaginary line M is the first inclination angle θ1. It was set as 55 A of 1st taper surfaces. However, the face shape between the fixing portion and the tapered surface of the bellofram may be an arc shape in the cross-sectional shape as seen in the bore direction of the piston.

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments, serve to explain the objects, advantages, and principles of the invention.

1 is a cross-sectional view showing a bellofram included in the vacuum open / close valve of the present embodiment.

FIG. 2 is an explanatory view for explaining the rubber molding member constituting the bellofram of the present embodiment, and is an enlarged view of the part shown in FIG. 1.

3 is an explanatory diagram for explaining the texture of bubbles in a bellofram of the present embodiment.

Fig. 4 is an explanatory diagram for explaining the configuration of the vacuum opening / closing valve of the present embodiment, showing the valve closing state.

FIG. 5 is an explanatory diagram for explaining the configuration of the vacuum open / close valve according to the present embodiment, and shows a valve open state.

FIG. 6 is an enlarged view of a portion P shown in FIG. 4.

FIG. 7 is a view showing the Q portion shown in FIG. 6, and is an explanatory view showing an enlarged view of the interval between the outer circumferential surface of the piston and the inner circumferential surface of the cylinder.

8 is a cross-sectional view showing the shape of the piston 40.

FIG. 9 is a cross-sectional view seen from the line A-A in FIG. 6 and is an explanatory diagram for explaining the form of a bellofram at the time of pressurization.

FIG. 10 is an explanatory view for explaining a configuration of a vacuum pressure control system including the vacuum open / close valve according to the present embodiment.

11 is an explanatory view for explaining a configuration of a conventional vacuum opening and closing valve.

FIG. 12 is an enlarged view of an R portion shown in FIG. 11.

13 is a cross-sectional view illustrating a conventional bellofram.

It is explanatory drawing for demonstrating the texture of a bubble among the conventional belloframs.

FIG. 15 is a cross-sectional view showing a conventional bellofram, and is an explanatory diagram for explaining the shape of the bellofram at the time of pressurization. FIG.

FIG. 16 is a cross-sectional view taken along line B-B of FIG. 15.

Claims (4)

In the vacuum opening and closing valve which can be connected between the vacuum container and the vacuum pump, A valve seat having a port connectable to one of the vacuum container or the vacuum pump, A valve element in contact with and dropping the valve seat, A piston which is driven by a fluid and moves the valve element, A cylinder in which the piston is received, and And a bellofram which deforms and seals a predetermined distance between the outer circumferential surface of the piston and the inner circumferential surface of the cylinder with the operation of the piston, In the vacuum opening and closing valve for controlling the vacuum pressure in the vacuum chamber by varying the opening degree of the valve element with respect to the valve seat, The bellofram includes a peripheral surface formed at a predetermined angle of inclination while being connected to the outer circumferential surface of the piston, The outer circumferential surface of the piston includes an inclined surface formed at a predetermined inclination angle, The bellofram and the piston have an inner circumference of a portion of the peripheral surface which contacts the piston of the bellofram when the valve element is in a position in contact with the valve seat. The outer diameter of the piston in contact with the bellofram is formed to be the same, The inclination angle of the bellofram and the inclination angle of the piston are formed to be the same, The peripheral surface of the bellofram includes a first and second inclined surfaces having different angles with respect to an axis along the stroke direction of the piston in a cross section along a central axis, An inclination angle of the bellofram is an inclination angle of the inclined surface having a smaller angle among the first and second inclined surfaces, Further comprising a rod connecting the valve element and the piston, An insertion hole into which the rod is inserted is formed in the bellofram, And the bellofram is positioned by fitting with the outer circumference of the rod using the insertion hole. The method of claim 1, The bellofram includes a fixing part fixed to the cylinder at the peripheral edge in the radial direction, The bellofram further includes an inflection portion connecting the first and second inclined surfaces, and the inflection portion is located toward the fixing portion, rather than a position in the axial center of the bellofram. Vacuum opening and closing valve. The method of claim 1, The bellofram is made of a rubber molding member embedded with rubber by insert molding, and the bubble has a flexible texture in a direction along a central axis of the bellofram. Vacuum opening and closing valve. The method of claim 3, The texture of the bubble is a vacuum opening and closing valve, characterized in that the tricot (tricot weave).

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