KR20090023146A - Vacuum opening/closing valve - Google Patents

Abstract

A vacuum switching valve is provided to prevent a bellofram from being curved by employing the bellofram having the same inner diameter and outer diameter. A vacuum switching valve comprises the following units. A bellofram(50) which is moved with a piston seals a predetermined interval formed by an external and an internal face of the piston. The piston driven by a fluid transfers a valve component. A cylinder accommodates the piston. The bellofram is formed at a predetermined angle. The external of the piston is inclined at the predetermined angle.

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 of a conventional bellows 150. 14 is an explanatory diagram for explaining the texture of air bubbles (base cloth (151B)) of the conventional bellows 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 the bellows ram 150 following the operation of the piston 140. Thus, airtightness in the air storage chamber AS is ensured.

As shown in FIG. 13, the bellows ram 150 has a trapezoidal cross-sectional shape when viewed from the bore (or radius) direction of the piston 140. The bellows 150 embeds and foams bubbles 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 bellows ram 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 plane with a short taper angle θp.

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

(a) In the vacuum open / close valve 100 having the bellows ram 150, the piston outer circumference dp of the outer circumferential surface of the piston 140 is larger than the inner diameter of the cylinder 130 by a portion having a predetermined interval 145. The small, tapered end 154 of the bellows ram 150 may extend along with the drive of the piston 140 to the top dead center position of the piston 140.

(b) In the vacuum opening / closing valve 100, when the valve is opened, the center portion 152 and the flange portion 153 of the bellows ram 150 are positioned at substantially the same height, as shown in Figs. The 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, The bellows 150 is easily stretchable in accordance with the opening and closing operation of the vacuum opening and closing valve 100.

On the other hand, a vacuum opening and closing valve driven by a bellows ram is disclosed in FIGS. 1, 5, and 6 of Japanese Patent Laid-Open Publication No. 2002-132354 and Japanese Patent Laid-Open Publication No. Hei 07-150623. In addition, about the bellows ram having inclined surfaces with different angles, FIGS. 1 and 4 of Japanese Patent Application Laid-Open No. 56-049462, FIG. 3 of Japanese Patent Application Laid-Open No. 61-140296 and 61 and 172230 are disclosed in FIGS. 1 and 5.

In addition, the formation of the valve pram by insert molding bubbles of tricot cloth is disclosed in Japanese Patent Laid-Open Nos. 10-317262 and 10-132077.

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 driving air is supplied to the air storage chamber AS, the pressing force by the driving air is in the center portion 152 of the bellows 150 and in the gap 145 between the piston 140 and the cylinder 130. It is applied to the folded end-taper surface 154 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. 12. It expands toward the inner circumferential surface of the cylinder 130 (see FIG. 15).

The shape of the bellows ram 150 is approximately trapezoidal, and since the short-taper surface 154 is radially outward of the axis AX from the outer circumferential surface of the piston 140, the direction of the bellows ram 150 is in the axis AX direction. In the same position as that, the tapered surface diameter length Dp of the surface in contact with the piston 140 of the bellows ram 150 in the radial direction at this position is larger than the piston outer circumference dp as shown by the dashed-dotted line in FIG. Big. Although the bellows ram 150 has a tapered surface, the piston 140 is cylindrical, therefore, the shortest diameter of the bellows ram 150 must be determined along the diameter of the piston 140, which is πDp of FIG. The difference between and πdp is large.

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 bellows ram 150 In portions of), portions that do not contact the outer circumferential surface of the piston 140 will form the 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 bellows ram 150 toward the outer circumferential surface of the piston 140 may be compared with the end-taper surface 154 of the crease generating portion 159 and the outer circumferential surface of the piston 140. It is greater than the pressure in the internal space between.

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 opening / closing valve is driven, this concentrated stress is repeatedly received, so that the bellows 150 is longitudinally cracked.

Applicant sells the vacuum opening and closing valve according to the present invention all over the world, but could not identify the cause of the problem regarding the durability of the bellows ram 150. Applicant finally found the cause through repeated experiments.

(2) Moreover, the bubble of the bellows ram 150 is formed by the mesh of the plain weave shown in FIG. 14, and since the flexibility of the mesh direction is low, it is difficult for the bellows ram 150 itself 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 bellows ram 150 are broken.

Due to the problems of (1) and (2), the drive air supplied into the air receiving chamber AS leaks through the bellows ram 150, and the opening degree of the vacuum open / close valve 100 cannot be controlled. There was a problem. For this reason, the bellows 150 needs to be replaced frequently, and a durable vacuum opening / closing valve has been requested.

The present invention has been made to solve the above problems, and in the vacuum opening and closing valve which seals the gap between the outer peripheral surface of the piston and the inner peripheral surface of the cylinder with a bellows following the operation of the piston, and drives the piston to open and close by fluid. To provide a durable vacuum opening and 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 includes 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 driven by a fluid and moving the valve element, a cylinder in which the piston is received, and It is provided with a bellows that 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. 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 and closing valve, the bellows ram includes a main surface formed at a predetermined inclination angle at the same time as the contact with the outer circumferential surface of the piston, the outer circumferential surface of the piston includes an inclined surface formed at a predetermined inclination angle, and the bellows and the piston are When the valve element is in contact with the valve seat, the inner circumference of the main surface portion in contact with the piston of the bellows ram and the outer circumference of the piston in contact with the bellows ram are equal, and the inclination angle of the bellows ram; The inclination angle of the piston is configured to be the same, and the main surface of the bellows ram includes first and second inclined surfaces having different angles from the axis along the stroke direction of the piston in a cross section along a central axis, and the bellows ram The inclination angle of is the inclination angle of the inclined surface having the smaller angle among the first and second inclined surfaces. The vacuum opening and closing valve further includes a rod connecting the valve element and the piston, wherein the bellows ram includes an insertion hole into which the rod is inserted, and the bellows ram is fitted with the outer circumference of the rod through the insertion hole. Is positioned by.

(2) In the vacuum opening / closing valve of (1), preferably, the bellows ram includes a fixing part fixed to the cylinder at a radial periphery, and the bellows ram is an inflection connecting the first and second inclined surfaces. It further comprises a portion, wherein the bent portion is located closer to the fixing portion than the axial center position of the bellows ram.

(3) In the vacuum opening / closing valve of (1), preferably, the bellows ram is formed of a rubber-forming member by insert molding a bubble having a texture that is flexible in rubber in a direction along the face of the bellows ram. .

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

The vacuum open / close valve of the present invention described in (1) is a vacuum open / close valve which is connected between the vacuum container and the vacuum pump and controls the vacuum pressure in the vacuum container by changing the opening degree of the valve element with respect to the valve seat. Is a vacuum opening / closing valve which seals a predetermined distance between the outer circumferential surface of the cylinder and the inner circumferential surface of the cylinder with a bellows following the operation of the piston and drives the piston to open and close by a fluid. When the outer circumferential surface of the piston is formed at a predetermined inclination angle and the valve element is in contact with the valve seat, the inner circumferential diameter of the bellows in contact with the piston and the outer diameter of the piston are the same, so that the vacuum opening / closing valve is closed. When the driving air enters the cylinder and the air pressure is applied to the valve, the inner diameter of the valve and the piston Since two weeks equal to the diameter does not occur at all flexion Belo diaphragm.

In the related art, since the piston has a cylindrical shape, the inner circumference contacting the piston of the bellows ram at a position corresponding to the piston cross section has to be larger than the outer circumference diameter of the piston. In the present invention, by providing an inclined surface on the outer circumference of the piston, it becomes possible to have the bellows inner circumferential diameter and the piston outer circumferential diameter 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 bellows ram and the inclination angle of the piston are the same. Therefore, the inner circumferential diameter of the bellows ram and the outer circumference of the piston even when the piston moves a certain distance. In order for the diameters to be the same, the bellows will not bend. Even if the inclination angle of the bellows ram is slightly larger than the inclination angle of the piston, when the valve element is in contact with the valve seat, if the inner circumference of the bellows in contact with the piston is equal to the outer circumference of the piston, the durability of the Applicant has confirmed by improvement to experiment. Applicants have confirmed by the experiment that the inclination angle of the bellows ram and the inclination angle of the piston are the same.

In the vacuum opening / closing valve of the present invention described in (1), the bellows ram 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. For example, in the case of having two tapered surfaces, the first taper angle θ1 is made larger than the single short taper angle θp of the conventional bellows ram with respect to the above angle ( θp <θ1 and smaller than the second taper angle θ2 (θ2 <θp).

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 the bellows rams in the respective positions, the inclination angle of the second tapered surface of the bellows ram can be made equal to the inclination angle of the tapered surface of the outer circumferential surface of the piston.

Therefore, since the bellows ram is provided with at least two tapered surfaces with different angles, it is possible to maintain the elasticity due to the opening and closing operation of the vacuum opening / closing valve, and to prevent the bellows ram from being damaged in a short time due to the cracks caused by the wrinkles. It can be suppressed.

In addition, in the vacuum opening / closing valve described in (1), the bellows is fitted with an outer circumference of the rod connecting the valve element and the piston, and an insertion hole for positioning the bellows ram is provided.

This makes it possible to accurately position the piston and the bellows via the rod.

However, when the vacuum opening / closing valve is opened or closed, when the tapered surface of the bellows ram is folded into a folded shape, the tapered surface is extended to the position of the top dead center or the bottom dead center of the piston according to the driving of the piston. Is located near the center of the stroke direction.

In the vacuum opening / closing valve of the present invention 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 bellows ram, even when the tapered surface of the bellows ram is folded in a fold form, There is no folding in the inflection.

Even if the vacuum opening / closing valve is repeatedly opened and closed, deterioration of the bellows due to repeated folding at the inflection section is not likely to be repeatedly folded at the inflection section where stress is more likely to be concentrated than other portions of the tapered surface of the bellows ram. Fatigue of the material constituting the bellows ram) can be prevented.

Therefore, it is possible to suppress the damage to the bellows prematurely.

In the vacuum opening / closing valve of the present invention as described in (3), the bellows ram is a rubber molded article in which a bubble having a textured texture is inserted into the direction along the face of the bellows ram with rubber.

As a result, the bellows ram can obtain the strength against the sealing property by the rubber and the pressing force of the fluid by the bubbles. Therefore, the bellows is easy to bend freely in response to the operation of the piston and the shape of the piston.

In addition, in the vacuum opening and closing valve of the present invention described in (4), since the bubble texture of the bellows ram is tricot, the bellows can easily bend freely in response to the operation of the piston and the shape of the piston when the fluid is pressurized. Lose.

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

Therefore, at an arbitrary position in the stroke direction of the piston in the bellows of the vacuum opening / closing valve of the present invention, wrinkles formed on the tapered surface are caused by the difference between the length in the peripheral direction of the tapered surface and the length in the peripheral direction of the outer peripheral surface of the piston. It can be made small compared with the bellows of the conventional vacuum opening / closing valve. In addition, such wrinkles do not exist locally on the periphery of the short-tapered face of the bellows, like the bellows of a conventional vacuum opening / closing valve, and are kept smaller than those of the conventional bellows. Scattered over the periphery. 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 bellows stem due to the friction between the bubbles of the folded tapered surface can be suppressed by the growth of the crack.

In addition, a tricot is a ribbed weave or knitted yarn which is the texture of the yarn of the form in which the mountain part and the curved part were arrange | positioned continuously successively in the predetermined direction like ridges, for example. It is a weaving method of the same type as the texture of the weaving, 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, the bellows ram includes a convex portion protruding in the thickness direction in the 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 piston is fitted with a convex portion and a concave portion, and is positioned and fixed on the concentric shaft.

Thereby, since there is no relative positional shift between the radial direction center part of a bellows ram and the hydraulic pressure surface of a piston, the data surface of a bellows ram can be bent or extended uniformly in the peripheral direction of a taper surface according to the operation of a piston. 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 drawing when the bellows 50 contained in the vacuum pressure valve 10 of this embodiment was seen in the bore direction BR of the piston 40. As shown in FIG. FIG. 2: is explanatory drawing for demonstrating the structure of the rubber molding member 51 which comprises the bellows ram 50, and is sectional drawing which expanded X part 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 bellows ram 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 distance 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 will be described later in detail, as shown in FIG. 1. It is sealed by 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 bellows ram 50 is a bellows comprised of the rubber molding member 51 which insert-molded the bubble 51B which has the texture of tricot fabric to the rubber 51A (refer FIG. 1 and FIG. 2). In addition, as shown in FIG. 3, a tricot is a ribbed weave which is the texture of the yarn of the shape arrange | positioned continuously and alternately in a predetermined direction like a ridge, for example, It is a weaving method of the same type as the texture of maryyasu (knitting), and 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 bellows ram 50 may be stretched to keep the effective hydraulic pressure area of the hydraulic pressure surface 43 of the piston 40 unchanged. Since the bellows ram 50 is constituted by the rubber molding member 51, the air bubbles 51B have a strength against the pressing force by the driving air AR supplied to the air accommodating chamber AS to the air bubbles 51B. It is given to 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 bellows 50 (rubber forming member 51).

As shown in FIG. 1, the bellows ram 50 has a piston 40 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. The first tapered surface 55A and the second tapered surface 55B which are different from the angle AX along the stroke direction ST (up-down direction in FIGS. 4 and 5) of FIG. All. In addition, this bellows 50 is between the annular flange part 54 (fixed part) located in the outer periphery of radial direction (bore direction BR of piston 40), and this flange part 54. It further includes the center part 52 (diameter direction center part) located in the center of radial direction through 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 bellows ram 50 is moved to the position of the top dead center of the piston 40. In the position near the center of the stroke direction ST, when the 2nd taper surface 55B is extended to the position of the top dead center of a piston with this movement, it is folded in a folded form.

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 bellows ram 50 is positioned at the piston 40 by inserting the convex portion 53 into the recess 44 of the piston 40. The bellows ram 50 has the center portion 52 in contact with the hydraulic pressure surface 43 of the piston 40, and the center portion 52 is located between the piston 40 and the plate-shaped fastener 46. Is inserted into the piston 40 and is fixed by screwing the piston 40 and the fixture 46.

The flange portion 54 of the bellows ram 50 is inserted into and fixed to the single acting pneumatic cylinder 30 and the flange holding portion 32.

When the piston 40 is at the bottom dead center position in the vacuum opening / closing valve 10, that is, when the driving air AR is not supplied to the air receiving chamber AS, the flange portion 54 of the bellows ram 50 is provided. ) And the center portion 52 become almost the same position as the stroke direction ST (see 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 bellows ram 50 has the flange portion 54 fixed to the flange holding portion 32 and the center portion 52 fixed to the hydraulic pressure surface 43 of the piston 40, respectively. The second tapered surfaces 55A and 55B are positioned in the gap 45 between the piston 40 and the cylinder 30, and the gaps 45 are closed while being folded or extended in accordance with the driving of the piston 40. I'm making it.

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

In the valve closing state where the O-ring 79 is completely in contact with the valve seat 73, when the driving air AR is supplied, the bellows ram 50 is in the position shown by the two-dot chain line in FIG. The point where the ram 50 contacts the piston 40 changes slightly. In the present invention, the upper end in which the bellows 50 is in contact with the piston 40 (the position indicated by the height L1, that is, the bellows 50 indicated by the dashed-dotted line in FIG. 7) is in contact with the piston 40. Position) the inner circumference of the bellows 50 is set to 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 bellows ram 50. The piston taper surface 40a is provided in the lower half of the piston 40. The upper half does not come into contact with the bellows 50 so it does not need to taper toward the end.

That is, W1 is an upper end of the piston in which the outer circumference of the piston is in contact with the bellows ram 50 when the O-ring 97 supplies the driving air AR in the valve closing state in contact with the valve seat 73. The outer diameter of the piston.

W2 is a bellow at the upper end where the bellows 50 are 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. It is the inner circumference of the piston 40 in contact with the pram 50.

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 tip of the piston is the upper end position in which the bellows 50 are in contact with the piston 40 in the bellows 50 shown by the dashed two-dotted 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 the O-ring 79 is in contact with the 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 ( The poppet valve element 76, which connects to 40, presses the valve seat 73 using an 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 ( Poppet valve element 76 along with 79 moves also toward the valve opening and falls off 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, in the cross-sectional shape of the bellows 50 as viewed in the bore direction BR of the piston 40, the angle formed with the axis AX is the first inclination angle θ1. It is a shape provided with 55 A of 1st taper surfaces which are (), and the 2nd taper surface 55B which is 2nd inclination angle (theta) 2.

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

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 bellows ram 150 is one in the conventional vacuum opening / closing valve 100, the end-taper surface 154 and the axis AX of the bellows ram 150 follow. The angle formed by the imaginary line N 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 bellows 50 of the vacuum opening / closing valve 10 has a single 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, which is inclined at the second inclination angle θ2 with respect to the axis AX, is formed toward the outer peripheral surface 41 of the piston 40 toward the cylinder inner circumferential surface 31 of 30, respectively. have.

On the other hand, the piston tapered surface 40a of the piston 40 is formed at the same inclination angle as the second inclined surface 55B of the bellows ram 50. As shown in FIG. 7, 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 bellows ram 50 is broken by the two-point broken line in FIG. 7. The location is as shown. At this time, at the upper end where the bellows 50 and the piston 40 are in contact, the inner circumferential diameter W2 is in contact with the piston 40 of the bellows 50 and the piston 40 is in contact with the bellows 50. Since the outer circumferential diameter (W1) of) is equal, the bellows 50 and the piston 40 are in close contact, as shown in FIG. Does not occur.

Thereafter, the point where the bellows 50 is in contact with the piston 40 is changed, but the piston tapered surface 40a of the piston 40 is formed at the same inclination angle as the second tapered surface 55B of the bellows ram 50. As a result, the bellows 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 and closing valve of the present embodiment, the vacuum opening 2 is connected between the vacuum chamber 2 and the vacuum pump 5, and the opening degree of the O-ring 79 serving as a valve element with respect to the valve seat 73 is determined. As the vacuum opening / closing valve 10 which changes and controls the vacuum pressure in the vacuum container 2, the piston 40 operates a predetermined distance between the outer circumferential surface of the piston 40 and the inner circumferential surface 31 of the cylinder 30. A vacuum opening / closing valve (10) which is sealed with a bellows (50) following and which opens and closes by driving the piston (40) by a fluid, and the bellows (50) are formed at a predetermined inclination angle (θ2). , The outer circumference of the piston 40 is formed at a predetermined inclination angle θ, the inner circumference of the bellows and the outer circumference of the piston in contact with the piston when the valve element is in contact with the valve seat Therefore, the driving air flows into the cylinder while the vacuum closing valve is closed. When the air pressure is applied to the bellows and the bellows, the inner circumferential diameter of the bellows and the piston's outer circumference are the same, so that no bending occurs in the bellows.

In the related art, since the piston has a cylindrical shape, the inner circumferential diameter in contact with the piston of the bellows ram at a position corresponding to the piston cross section has to be made 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, it becomes possible to make the bellows inner circumferential diameter and the outer circumferential diameter of the piston the same length in 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 bellows ram 50 and the inclination angle θ of the piston 40 are the same, the piston 40 moves to a certain distance. Even at this time, since the inner circumferential diameter of the bellows 50 in contact with the piston 40 and the outer circumferential diameter of the piston 40 are the same, no bending occurs in the bellows ram 50.

Even when the inclination angle θ2 of the bellows ram 50 is slightly larger than the inclination angle θ of the piston 40, when the O-ring 79 serving as the valve element is in the position in contact with the valve seat 73, the piston 40 Applicant has confirmed by experiment that if the inner circumferential diameter of the bellows 50 in contact with) and the outer circumferential diameter of the piston 40 are the same, the durability of the bellows 50 is remarkably improved. Applicants have confirmed by experiment that the inclination angle θ2 of the bellows ram 50 and the inclination angle θ of the piston 40 are the same, which further improves durability.

In addition, since the bellows ram 50 includes two of the first taper surface 55A and the second taper surface 55B, the bellows ram 50 can maintain the elasticity associated with the opening / closing operation of the vacuum opening / closing valve 10. At the same time, the bellows 50 can be prevented from being damaged in a short time due to cracks generated due to wrinkles.

In addition, the inflected portion 56 connecting the first taper surface 55A and the second taper surface 55B in the vacuum opening / closing valve 10 has a planar position rather than a central position of the axis AX of the bellows ram 50. Because it is located on the branch 54 side, even when the second tapered surface 55B of the bellows ram 50 is folded in a folded shape, it is not folded in the inflection portion 56.

Even if the vacuum opening / closing valve 10 is repeatedly opened and closed, the second tapered surface is formed 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 bellows ram 50. Since the folding of the 55B is not performed repeatedly, the occurrence of deterioration of the bellows 50 (material fatigue of the rubber molding member 51) caused by the repeated folding in the inflection portion 56 can be prevented. have.

Therefore, it is possible to suppress the bellows 50 from being damaged early.

In addition, in the vacuum opening / closing valve 10 of the present embodiment, the piston rod 48 connecting the piston 40 and the poppet valve element 76 holding the O-ring 79 as the valve element 50 is a valve element. By fitting the outer periphery of the bellows 50 to the piston 40, the through-hole 57 is positioned so that the bellows 50 can be easily and accurately positioned on the piston 40. FIG. Can be.

In the vacuum opening / closing valve 10, the bellows ram 50 has a texture of flexible tricot fabric in the direction along the surface 51a of the bellows ram 50 on the rubber 51A by insert molding. The rubber molding member 51 which embed | buried the bubble 51B 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. It is easy to bend freely according to the shape of the bellows.

In particular, in the vacuum opening / closing valve 10 of the present embodiment, since the texture of the bubbles 51B of the bellows 50 is tricot, the second taper of the bellows 50 is supplied at the time of supply of the drive air AR. When the surface 55B expands along the outer circumferential surface 41 of the piston 40, the bellows fem 50 is easily bent to follow the shape of the outer circumferential surface 41 of the piston 40.

In addition, in the vacuum opening / closing valve 10, the bellows 50 and the piston 40 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 the first and second tapered surfaces 55A of the bellows ram 50 are not present. , 55B can be bent or extended evenly in the peripheral direction of the first and second tapered surfaces 55A, 55B in accordance with the operation of the piston 40. 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 adjusted. Can be sealed in proper condition.

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 bellows ram may be shaped such that both are positioned by insertion of the concave portion of the piston and the convex portion of the bellows ram. The shape of the concave portion and the convex portion can be appropriately changed.

Moreover, in the bellows 50 in this embodiment, the annular agent which makes the angle which makes the virtual line M the 1st inclination angle (theta) 1 between the inclination starting point part 54S and the inflection part 56 is It was set as 55 A of 1 taper surfaces. However, the surface shape between the fixed portion and the tapered surface of the bellows 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 the bellows included in the vacuum open / close valve of the present embodiment.

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

It is explanatory drawing explaining the texture of foam | bubble among the bellows ram of this 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 the bellows ram under pressure.

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 showing a conventional bellows ram.

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

It is sectional drawing which shows the conventional bellows ram, and is explanatory drawing for demonstrating the shape of the bellows ram at the time of pressurization.

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 the valve seat and capable of falling, A piston which is driven by a fluid and moves the valve element, A cylinder in which the piston is received, and And a bellows that deforms and seals a predetermined distance between an outer circumferential surface of the piston and an inner circumferential surface of the cylinder together with the operation of the piston. In the vacuum opening and closing valve for controlling the vacuum pressure in the vacuum container by changing the opening degree of the valve element with respect to the valve seat, The bellows ram includes a main surface which is connected to an outer circumferential surface of the piston and formed at a predetermined inclination angle. The outer circumferential surface of the piston includes an inclined surface formed at a predetermined inclination angle, The bellows and the piston are formed such that the inner circumference of the main surface portion in contact with the piston of the bellows and the outer circumference of the piston in contact with the bellows when the valve element is in the position in contact with the valve seat. Become, The inclination angle of the bellows ram and the inclination angle of the piston are formed to be the same, The main surface of the bellows ram includes first and second inclined surfaces having different angles from an axis along a stroke direction of the piston in a cross section along a central axis, An inclination angle of the bellows ram is an inclination angle of an 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 pod is inserted is formed in the bellows ram, And the bellows ram is positioned by fitting with the outer circumference of the rod using the insertion hole. The method of claim 1, The bellows ram includes a fixing part fixed to the cylinder at the peripheral edge in the radial direction, The bellows ram further includes an inflection portion connecting between the first and second inclined surfaces, wherein the inflection portion is located on the fixing side, rather than a position in the axial center of the bellows ram. The method of claim 1, The bellows ram is a vacuum opening valve, characterized in that it comprises a rubber molded member of the foam insert having a flexible texture in the direction along the surface of the bellows ram on the rubber. The method of claim 3, The texture of the bubble is a vacuum opening and closing valve, characterized in that the tricot.

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