Fluid control valve

Abstract

In the present invention, the center of a diaphragm member 34 is positioned on the extension line of the axial center CL of an operating lever 9, the diaphragm member 34 is formed in a spherical crown shape bulging toward the operating lever 9 side, and the diaphragm member 34 is sandwiched at the apex of the diaphragm member 34 from both sides in a direction parallel to the axial center CL by a first sandwiching piece 93 that contacts the diaphragm member 34 from the operating lever 9 side and a second sandwiching piece 323 that contacts the diaphragm member 34 from the operating lever 9 side. The first clamping piece 93 and the second clamping piece 323 are formed in a circular shape coaxial with the operation rod 9, the diameter D11 of the first clamping piece 93 is larger than the diameter D of the second clamping piece 323, the surface of the first clamping piece 93 facing the diaphragm member 34 is a convex spherical surface 94, the convex spherical surface 94 is formed in a manner of bulging toward the diaphragm member 34, and the diameter D of the convex spherical surface 94 is larger than the diameter D of the second clamping piece 323. A center is arranged on the axis CL of the operation rod 9.

Description

Technical Field

[0001] The present invention relates to a fluid control valve, which comprises an operating rod, a valve core connected to the operating rod, a valve seat for the valve core to engage and disengage, and a diaphragm located between the operating rod and the valve core. The fluid is controlled by the valve core driven by the operating rod to engage and disengage along the axis of the operating rod. Background Art

[0002] Film formation in semiconductor manufacturing processes uses a variety of process gases. Fluid control valves are used to control the flow rates of these process gases. Known examples of fluid control valves include those disclosed in Patent Documents 1 and 2. The fluid control valve disclosed in Patent Document 1 is a pneumatic on-off valve that controls the flow rates of process gases by moving a diaphragm member into and out of contact with a valve seat.

[0003] More specifically, the valve stem (diaphragm pressing member) abuts the apex of the spherical diaphragm member. The actuator's action presses the diaphragm member, deforming it and bringing it into contact with the valve seat. The diaphragm member abutting the valve seat represents the closed state of the fluid control valve. Subsequently, when the valve stem releases its pressure on the diaphragm member, the diaphragm member's self-restoring force returns to its original spherical shape, freeing it from the valve seat. This free-standing state represents the open state of the fluid control valve. [Prior art literature] [Patent Document]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-180490 [Patent Document 2] Japanese Patent Application Laid-Open No. 2017-223318 Summary of the Invention [Problems to be solved by the invention]

[0005] However, the process gas used in atomic layer deposition (ALD), a film-forming technology that has become increasingly popular in recent years, has a high temperature (around 200 degrees Celsius). Therefore, the diaphragm member's self-restoring force decreases at this high temperature, and there is a risk that the fluid control valve may not fully return to its original spherical crown shape when the valve is opened from the closed state. If the diaphragm member cannot fully return to its original spherical crown shape, the distance between the diaphragm member and the valve seat in the open state decreases, leading to concerns about a decrease in the Cv value. In order to shorten the semiconductor film-forming process as much as possible and improve productivity, the industry desires a higher Cv value for fluid control valves (that is, to increase the amount of gas that can pass through at a time). Against this backdrop, a decrease in the Cv value caused by a decrease in the self-restoring force of the diaphragm member as described above is undesirable.

[0006] Therefore, as a countermeasure to the problem of the reduction of the self-restoring force of the diaphragm member at high temperature, the inventors of the present application have considered usingFigure 5 A fluid control valve 100 as shown.

[0007] The fluid control valve 100 includes an actuator 4, which includes a pneumatically driven cylinder 6. Figure 5 A piston (not shown) is installed in the fluid control valve 100 in a manner that slides in the vertical direction. The operating rod 11 is moved up and down by the up and down movement of the piston. Furthermore, a valve core 32 is connected to the top of the operating rod 11. The valve core 32 is engaged and separated from the valve seat 33 as the operating rod 11 moves up and down. In addition, the diaphragm member 34 is formed in a disc shape, the outer periphery of which is clamped and fixed in the fluid control valve 100, and the central part is Figure 5 The vertical direction of the valve body is clamped by the clamping portion 111 of the operating rod 11 and the valve core 32.

[0008] In the fluid control valve 100 as described above, when the valve element 32 and the valve seat 33 are in contact and separated, the diaphragm member 34 is in contact with the valve seat 33. Figures 6A-6C Deformed as shown. Figure 6A To express Figure 5 FIG. 1 shows a diagram of the diaphragm member 34 when the fluid control valve 100 is in an open state. Figure 6B To express Figure 5 FIG. 1 is a diagram showing the deformation of the diaphragm member 34 immediately after the valve element 32 of the fluid control valve 100 starts to move in the contact direction. Figure 6C To express Figure 5 FIG. 1 shows a diagram illustrating deformation of the diaphragm member 34 when the fluid control valve 100 is in a closed state.

[0009] When the fluid control valve 100 is in the open state, the diaphragm member 34 is in a state close to the natural state in which no deformation occurs ( Figure 6A Then, when the operating rod 11 is driven in the contact direction to make the valve core 32 contact the valve seat 33, the diaphragm member 34 moves from the center portion clamped by the operating rod 11 (clamping portion 111) and the valve core 32 toward the valve seat 33 (reference Figure 5 ) press down and start to deform ( Figure 6B Then, when the valve core 32 has abutted against the valve seat 33, that is, when the fluid control valve 100 has become a closed valve state, the diaphragm member 34 has undergone the maximum deformation state ( Figure 6C ).

[0010] Furthermore, in order to change the valve closed state to the valve open state, the operating rod 11 is driven upward in the figure. As a result, the operating rod 11 and the valve core 32 move in the same direction, so the valve core 32 leaves the valve seat 33, and the fluid control valve 100 becomes the valve open state. At this time, since the diaphragm member 34 is clamped by the operating rod 11 (clamping portion 111) and the valve core 32, the center portion is lifted in the direction away from the valve seat 33, so that it can be reliably returned to the valve seat. Figure 6ATherefore, even in a high-temperature environment such as when a high-temperature process gas is used as the control fluid, it is possible to prevent the diaphragm member 34 from not being able to return to its original shape.

[0011] However, the fluid control valve 100 described above has the following problems. The inventors of this application have found that the diaphragm member 34 is Figures 6A-6C When deformed as shown, stress concentrates on the clamped portion P21 of the diaphragm member 34. If the stress-concentrated portion of the diaphragm member 34 remains fixed, the diaphragm member 34 may be damaged at the stress-concentrated portion P21 when the valve element 32 of the fluid control valve 100 repeatedly engages and disengages from the valve seat 33.

[0012] Furthermore, with the recent industry demand for higher Cv values ​​in fluid control valves, there's a desire to increase the distance (stroke) between the valve core's open and closed positions compared to conventional valves. However, increasing the stroke increases the deformation of the diaphragm valve core. This increased deformation increases the likelihood of damage to the diaphragm member 34 due to the stress concentration at portion P21 mentioned above. In other words, the stress concentration on the diaphragm member 34 prevents the stroke from being increased.

[0013] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a fluid control valve capable of increasing the stroke amount. [Technical means to solve the problem]

[0014] In order to solve the above-mentioned problems, a fluid control valve according to one aspect of the present invention has the following structure.

[0015] (1) A fluid control valve comprising an operating rod, a valve core connected to the operating rod, a valve seat for the valve core to engage and disengage, and a diaphragm member located between the operating rod and the valve core, wherein the valve core driven by the operating rod engages and disengages along the axis of the operating rod to control the fluid, and the fluid control valve is characterized in that the center of the diaphragm member is located on the extension line of the axis, and the diaphragm member is formed into a spherical crown shape that bulges toward the operating rod side, and the top of the diaphragm member is parallel to the axis. The first clamping piece and the second clamping piece are clamped from both sides in the direction of the row, the first clamping piece contacts the diaphragm component from the operating rod side, and the second clamping piece contacts the diaphragm component from the valve core side, the first clamping piece and the second clamping piece are formed into a circular shape coaxial with the operating rod, the diameter of the first clamping piece is larger than the diameter of the second clamping piece, the surface of the first clamping piece facing the diaphragm component is a convex spherical surface, and the convex spherical surface is formed in a manner of bulging toward the diaphragm component side and has a center on the axis.

[0016] (2) In the fluid control valve described in (1), preferably, a first radius which is a radius of the convex spherical surface is smaller than a second radius which is a radius of a spherical surface of the diaphragm member facing the convex spherical surface.

[0017] (3) In the fluid control valve described in (2), the first radius is preferably not less than 50% and not more than 65% of the second radius.

[0018] (4) In the fluid control valve described in any one of (1) to (3), the diameter of the first clamping piece preferably exceeds 35% of the diameter of the diaphragm member when projected onto a plane perpendicular to the axis.

[0019] According to the above-mentioned fluid control valve, when the valve core is intended to abut against the valve seat, the diaphragm member begins to deform by being pressed downward toward the valve seat from the vertex portion clamped by the first clamping piece and the second clamping piece. During this deformation, the diaphragm member deforms along the shape of the convex spherical surface of the first clamping piece, so the contact range between the convex spherical surface and the diaphragm member expands from the center portion of the diaphragm member toward the outer periphery as the valve core approaches the valve seat. The inventors of this application confirmed through finite element analysis that the area of ​​stress concentration in the diaphragm member at this time is the outermost portion of the contact range. In other words, when the valve core is switched from an open state to a closed state, the area of ​​stress concentration in the diaphragm member moves as the contact range changes and is not fixed. Therefore, even if the valve core is repeatedly engaged and disengaged, the diaphragm member is not easily damaged. In this way, by making the diaphragm member less susceptible to damage, the distance (stroke) between the valve core's open and closed positions can be increased compared to the past. If the stroke can be increased, the distance between the valve core and the valve seat in the open state will increase, so the Cv value of the fluid control valve will increase. [Effects of the Invention]

[0020] According to the fluid control valve of the present invention, the stroke amount can be increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a cross-sectional view of the fluid control valve of this embodiment. Figure 2 for Figure 1 A partial enlarged view of part A. Figure 3 A three-dimensional diagram of the diaphragm component. Figure 4A This is a diagram showing the appearance of the diaphragm member when the fluid control valve according to the present embodiment is in the valve open state. Figure 4B This is a diagram showing how the diaphragm member is deformed immediately after the valve element of the fluid control valve according to the present embodiment starts moving in the contact direction. Figure 4CIt is a diagram showing how the diaphragm member is deformed when the fluid control valve according to the present embodiment is in the valve closed state. Figure 5 A cross-sectional view of a fluid control valve invented by the present inventors as a solution to the problem that the self-restoring force of a diaphragm member decreases at high temperatures. Figure 6A To express Figure 5 The diagram shows the appearance of the diaphragm member of the fluid control valve when it is in the valve open state. Figure 6B To express Figure 5 FIG. 1 is a diagram showing deformation of a diaphragm member immediately after a valve element of a fluid control valve starts moving in the contact direction. Figure 6C To express Figure 5 FIG. 1 is a diagram showing deformation of a diaphragm member when the fluid control valve is in a closed state. Figure 7 This is a graph showing the relationship between the amount of movement of the valve element from the position in the valve open state toward the contact direction and the stress generated in the diaphragm member. Figure 8 This is a graph showing the relationship between the valve core stroke and Cv value at high temperature. DETAILED DESCRIPTION

[0022] While referring to the accompanying drawings, embodiments of the fluid control valve of the present invention will be described in detail. Note that the drawings used in the description are simplified for the purpose of explanation and do not accurately represent shapes, dimensions, etc.

[0023] (About the structure of the fluid control valve) The structure of the fluid control valve 1 according to the present embodiment will be described using the drawings. Figure 1 It is a cross-sectional view of the fluid control valve 1 according to this embodiment. Figure 2 for Figure 1 A partial enlarged view of part A. Figure 3 It is a perspective view of the diaphragm member 34.

[0024] The fluid control valve 1 is a pneumatically driven gas valve provided in the gas supply system of a semiconductor manufacturing device. Figure 1 As shown, it is composed of a drive unit 2 and a valve unit 3. Furthermore, the drive unit 2 is composed of an actuator unit 4 and a spring unit 5.

[0025] First, the actuator unit 4 will be described. The actuator unit 4 includes a pneumatically driven cylinder 6 and a connecting frame 7 for connecting the cylinder 6 and the spring unit 5 .

[0026] The cylinder 6 comprises a cylindrical cylinder 61, a piston (not shown) loaded inside the cylinder 61, and a cylindrical drive shaft (not shown) coupled to the piston. Figure 1 The drive shaft moves forward and backward along its axial direction as the piston moves up and down. Figure 1 The direction parallel to the up-down direction in the figure is consistent with the direction in which the valve core 32 described later approaches and separates from the valve seat 33. Furthermore, the upper side in the figure is the separation direction, and the lower side is the contact direction.

[0027] The top end of the valve portion 3 side of the drive shaft of the cylinder 6 protrudes from the cylinder tube 61 and is connected to a cylindrical operating rod 9 located coaxially with the drive shaft. Therefore, as the drive shaft of the cylinder 6 advances and retreats, the operating rod 9 also moves along its axis CL (reference Figure 2 )advance and retreat.

[0028] The operating rod 9 is inserted into the spring portion 5 and extends from the connecting frame 7 to the valve portion 3. Figure 2 As shown, the operating rod 9 is provided with an expanded diameter portion 91 having a larger diameter than the portion inserted through the connecting frame 7 and the portion inserted through the spring portion 5 at the portion inserted into the valve portion 3, thereby forming a step portion 92. Furthermore, the operating rod 9 is provided with a first clamping piece 93 at the end of the expanded diameter portion 91 on the side opposite to the step portion 92. The first clamping piece 93 is used to clamp the diaphragm member 34 described later together with the second clamping piece 323 described later. The first clamping piece 93 is a circular shape with a radial direction perpendicular to the axis CL of the operating rod 9 and is coaxial with the axis CL. The diameter D11 of the first clamping piece 93 is larger than the diameter of the expanded diameter portion 91. In addition, the surface of the first clamping piece 93 facing the diaphragm member 34 is a convex spherical surface 94 formed in a manner that bulges toward the diaphragm member 34 side. The center of the convex spherical surface 94 is located on the axis CL of the operating rod 9. The radius (first radius) of the convex spherical surface 94 is set to, for example, approximately 70 mm. In addition, the outer periphery of the convex spherical surface 94 is R-shaped chamfered.

[0029] Furthermore, a female thread portion 95 is formed on the end surface of the operating rod 9 on the valve portion 3 side, and a valve element 32 described later is screwed therein.

[0030] Next, the spring unit 5 will be described. The spring unit 5 includes a compression coil spring 52 coaxially positioned with the operating rod 9 within an internal space 51. The compression coil spring 52 is compressed by an end surface 53 of the internal space 51 on the actuator unit 4 side and by a step 92 of the operating rod 9. Therefore, the compression coil spring 52 constantly urges the operating rod 9 in the contact direction (downward in the figure).

[0031] Next, the valve unit 3 is described. The valve unit 3 includes a valve body 31, a valve element 32, a valve seat 33, and a diaphragm member 34. The valve body 31 includes a cylindrical portion 315 connected to the spring portion 5. Furthermore, a valve chamber 311 is formed inside the cylindrical portion 315 of the valve body 31.

[0032] The valve chamber 311 is connected to the input flow path 313 via the valve port 312 at the center of the bottom. The input flow path 313 is used to input the process gas into the valve chamber 311. In addition, a circular valve seat 33 is fixed to the bottom surface of the valve chamber 311 on the outer peripheral side of the valve port 312 and coaxially with the valve port 312. The valve seat 33 is made of, for example, PI (polyimide) or PFA (tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer) with excellent heat resistance. Furthermore, the valve chamber 311 is connected to the output flow path 314 on the radial outside of the valve seat 33. The output flow path 314 is used to output the process gas from the valve chamber 311.

[0033] The valve core 32 is made of, for example, stainless steel. It includes a cylindrical main body 321 and a male threaded portion 322 on the operating rod 9 side of the main body 321. The valve core 32 is connected to the operating rod 9 by screwing the male threaded portion 322 into the female threaded portion 95 of the operating rod 9.

[0034] In addition, the valve core 32 is provided with a second clamping piece 323 on the side of the main body 321 opposite to the male thread portion 322. The second clamping piece 323 is a circular shape with a radial direction perpendicular to the axis CL of the operating rod 9 and is coaxial with the axis CL. The diameter D12 of the second clamping piece 323 is smaller than the diameter D11 of the first clamping piece 93. By connecting the valve core 32 to the operating rod 9, the second clamping piece 323 and the first clamping piece 93 are connected from the operating rod 9. Figure 2 The diaphragm member 34 is clamped in the up-down direction. The second clamping piece 323 has a surface facing the diaphragm member 34 that is a flat surface, and the outer periphery of the flat surface is chamfered in an R shape.

[0035] The valve core 32 also has an abutment portion 324 on the side of the second clamping piece 323 opposite the main body 321, which engages and disengages the valve seat 33. This abutment portion 324 is also circular and coaxial with the axis CL of the operating rod 9. Because the valve core 32 is connected to the operating rod 9, the abutment portion 324 engages and disengages the valve seat 33 along the direction of the axis CL as the operating rod 9 advances or retreats.

[0036] The diaphragm member 34 is made of, for example, a Ni alloy. In addition, the center of the diaphragm member 34 is located on the extension line of the axis CL, and the diaphragm member 34 is formed in the shape of a spherical crown that bulges toward the operating rod 9 side. Therefore, the facing surface 341 of the diaphragm member 34 that faces the convex spherical surface 94 is a spherical surface. The radius of the sphere of the facing surface 341 (the second radius) is set to, for example, approximately 140 mm. Furthermore, the back surface of the facing surface 341 is set as the back surface 342. An opening 343 is provided at the vertex of the diaphragm member 34 (facing surface 341). The opening 343 is a circular shape that is radially perpendicular to the axis CL and is coaxial with the axis CL. In addition, a planar edge 344 that is perpendicular to the axis CL is provided on the outer periphery of the facing surface 341. The edge 344 is a circular shape that is radially perpendicular to the axis CL.

[0037] The diaphragm member 34 as described above is fixed to the inside of the fluid control valve 1 as follows. The male threaded portion 322 of the valve core 32 is inserted into the opening 343 of the diaphragm member 34 from the side opposite to the facing surface 341, and the diaphragm member 34 and the valve core 32 are positioned coaxially in a state where the back surface 342 of the diaphragm member 34 contacts the second clamping piece 323 of the valve core 32. Then, the female threaded portion 95 of the operating rod 9 is screwed into the male threaded portion 322 until the convex spherical surface 94 of the first clamping piece 93 contacts the spherical surface 341 of the diaphragm member 34. In this way, the diaphragm member 34 is fixed to the inside of the fluid control valve 1 as follows. Figure 1 or Figure 2 As shown in FIG. 3 , the edge of the opening 343 is clamped from both sides by the first clamping piece 93 and the second clamping piece 323 in the direction of the axis CL (the vertical direction in the figure). That is, the operating rod 9 is connected to the diaphragm member 34. Furthermore, the edge 344 of the diaphragm member 34 is like Figure 1 or Figure 2 As shown, the diaphragm member 34 is clamped and fixed from the upper and lower directions within the valve portion 3. By fixing the diaphragm member 34 inside the fluid control valve 1 as described above, the interior of the cylindrical portion 315 of the valve body 31 is divided into the valve chamber 311 and the upper part of the valve chamber 311, and the diaphragm member 34 repeatedly elastically deforms as the valve core 32 moves in the closing and closing directions.

[0038] (About the operation of the fluid control valve) The operation of changing the fluid control valve 1 from the open state to the closed state will be described. Figure 1As shown, the fluid control valve 1 is in the open state. As described above, the operating rod 9 is constantly biased in the abutment direction by the compression coil spring 52. Therefore, the open state is when the actuator 4 is pulling the operating rod 9 upward in the figure against the force of the compression coil spring 52. To return to the closed state from this state, the supply of operating air to the cylinder 6 must be stopped. Consequently, the operating rod 9 and the valve core 32 are pressed downward toward the valve seat 33 by the force of the compression coil spring 52, causing the abutment portion 324 of the valve core 32 to abut against the valve seat 33.

[0039] Next, use Figures 4A-4C The deformation of the diaphragm member 34 when the valve-open state is changed to the valve-closed state as described above will be described. Figure 4A This is a diagram showing the appearance of the diaphragm member 34 when the fluid control valve 1 according to the present embodiment is in the valve open state. Figure 4B This is a diagram showing how the diaphragm member 34 is deformed immediately after the valve element 32 of the fluid control valve 1 according to the present embodiment starts moving in the contact direction. Figure 4C 1 and 2 are diagrams showing how the diaphragm member 34 is deformed when the fluid control valve 1 according to the present embodiment is in the valve closed state.

[0040] When the fluid control valve 1 is in the open state, the diaphragm member 34 is in a state close to the natural state without deformation ( Figure 4A Then, when the operating rod 9 is driven in the contact direction and the valve core 32 is about to contact the valve seat 33, the diaphragm member 34 moves from the central portion clamped by the first clamping piece 93 and the second clamping piece 323 toward the valve seat 33 (refer to Figure 2 ) press down and start to deform ( Figure 4B Then, when the valve core 32 has abutted against the valve seat 33, that is, when the fluid control valve 1 has become a closed valve state, the diaphragm member 34 has undergone the maximum deformation state ( Figure 4C During this deformation, the diaphragm member 34 deforms along the shape of the convex spherical surface 94, so the contact range A11 between the convex spherical surface 94 of the first clamping piece 93 and the facing surface 341 of the diaphragm member 34 expands from the center toward the outer peripheral side as the valve core 32 approaches the valve seat 33 ( Figure 4B 、 Figure 4C ).

[0041] The inventors of this application used finite element analysis to confirm that when the diaphragm member 34 deforms as described above, stress concentrates at the outermost periphery P11 of the contact area A11. This means that when the diaphragm member 34 is moved from the open state to the closed state, the stress concentration area in the diaphragm member 34 shifts with the changes in the contact area A11 and is not fixed. Therefore, even with repeated engagement and disengagement of the valve core 32, the diaphragm member 34 is less susceptible to damage. By making the diaphragm member 34 less susceptible to damage, the distance (stroke) between the open and closed positions of the valve core 32 can be increased compared to conventional methods. Increasing the stroke increases the distance between the valve core 32 and the valve seat 33 in the open state, thereby increasing the Cv value of the fluid control valve 1.

[0042] Here, if Figure 4B 、 Figure 4C As shown, in order to deform the diaphragm member 34 along the shape of the convex spherical surface 94, it is ideal that the radius of the convex spherical surface 94 is not less than 50% and not more than 65% of the radius of the spherical surface 341. Furthermore, in this embodiment, the radius of the convex spherical surface 94 (first radius) is approximately 70 mm, while the radius of the facing surface 341 of the diaphragm member 34 (second radius) is approximately 140 mm.

[0043] Furthermore, by increasing the diameter D11 of the first clamping piece 93 as much as possible, a larger stroke amount can be ensured. Specifically, the diameter D11 of the first clamping piece 93 (refer to Figure 2 ) is preferably greater than the diameter D21 of the diaphragm member 34 (reference Figure 3 The diameter D21 of the diaphragm member 34 is the diameter when the diaphragm member 34 is projected onto a plane perpendicular to the axis CL of the operating rod 9. That is, in this embodiment, the diameter D21 of the diaphragm member 34 is the diameter of the edge portion 344.

[0044] Specific use Figure 7 and Figure 8 To explain. Figure 7 In order to show the relationship between the movement amount (stroke amount) of the valve core 32 from the position in the valve open state (hereinafter referred to as the valve open position) toward the abutment direction and the stress generated in the diaphragm member, a graph is provided, in which the cases where the diameter D11 of the first clamping piece 93 is set to 35% of the diameter D21 of the diaphragm member 34, the case where it is set to 65% of the diameter D21, and the case where it is set to 85% of the diameter D21 are compared. Figure 7 The waveform formed by the single-dot chain line in is the waveform when the diameter D11 is set to 35% of the diameter D21. Figure 5 The relationship between the diameter of the clamping portion 111 and the diameter of the diaphragm member 34 in the fluid control valve 100 is shown. Figure 7The waveform formed by the solid line in FIG is a waveform when the diameter D11 is set to 65% of the diameter D21. Figure 7 The waveform formed by the dotted line in is the waveform when the diameter D11 is set to 85% of the diameter D21. And, the rising part of each waveform indicates that stress concentration has occurred to the extent that the diaphragm member 34 is damaged. In addition, Figure 8 This is a graph showing the relationship between the stroke amount and the Cv value at high temperature of the valve element 32. It shows that the Cv value increases as the stroke amount increases.

[0045] When the diameter D11 of the first clamping piece 93 is set to 35% of the diameter D21 of the diaphragm member 34, a rising waveform is observed when the movement amount of the valve element 32 reaches S1 (refer to Figure 7 ). That is, when the displacement of the valve core 32 reaches S1, stress concentration occurs to the extent that the diaphragm member 34 is damaged. Therefore, the maximum stroke can be ensured to be S1. The Cv value of the fluid control valve 1 (fluid control valve 100) when the stroke is ensured to be S1 is C1 (refer to Figure 8 ).

[0046] For example, when the diameter D11 of the first clamping piece 93 is set to about 65% of the diameter D21 of the diaphragm member 34, a rising waveform is observed when the movement amount of the valve element 32 reaches S2 (see Figure 7 ). That is, when the movement of the valve core 32 reaches S2, stress concentration occurs to the extent that the diaphragm member 34 is damaged. Therefore, the maximum stroke amount can be ensured to be S2. This stroke amount is about 1.8 times the stroke amount when the diameter D11 is set to 35% of the diameter D21. The Cv value of the fluid control valve 1 when the stroke amount is S2 is C2 (refer to Figure 8 This is approximately 1.5 times the Cv value when the diameter D11 is set to 35% of the diameter D21.

[0047] For example, when the diameter D11 of the first clamping piece 93 is set to about 85% of the diameter D21 of the diaphragm member 34, a rising waveform is observed when the movement amount of the valve element 32 reaches S3 (see FIG. Figure 7 ). That is, when the movement of the valve core 32 reaches S3, stress is generated to the extent that the diaphragm member 34 is damaged. Therefore, the maximum stroke amount can be ensured to be S3. This stroke amount is about 2.5 times the stroke amount when the diameter D11 is set to 35% of the diameter D21. The Cv value of the fluid control valve 1 when the stroke amount is S3 is C3 (refer to Figure 8 This is approximately 1.65 times the Cv value when the diameter D11 is set to 35% of the diameter D21.

[0048] As described above, if the diameter D11 of the first clamping piece 93 exceeds 35% of the diameter D21 of the diaphragm member 34, then Figure 7 As shown, the rise of the waveform can be delayed compared to the rise when the diameter D11 is set to 35% of the diameter D21. This allows the valve core 32 to move more significantly, increasing the stroke. Furthermore, as long as the structure of the fluid control valve 1 allows, the larger the diameter D11 of the first clamping piece 93, the better. However, in practice, it is smaller than the diameter D21 of the diaphragm member 34.

[0049] As described above, the fluid control valve 1 of this embodiment is as follows, that is, (1) a fluid control valve 1, comprising an operating rod 9, a valve core 32 connected to the operating rod 9, a valve seat 33 for the valve core 32 to engage and disengage, and a diaphragm member 34 located between the operating rod 9 and the valve core 32, wherein the control of the fluid is achieved by engaging and disengaging the valve core 32 driven by the operating rod 9 in the direction of the axis CL of the operating rod 9, and the fluid control valve 1 is characterized in that the center of the diaphragm member 34 is located on the extension line of the axis CL, and the diaphragm member 34 is formed into a spherical crown shape that bulges toward the operating rod 9 side, and the apex portion (opening 343) of the diaphragm member 34 is located at the top. It is clamped from both sides by the first clamping piece 93 and the second clamping piece 323 in a direction parallel to the axis CL, the first clamping piece 93 contacts the diaphragm member 34 from the operating rod 9 side, and the second clamping piece 323 contacts the diaphragm member 34 from the valve core 32 side, the first clamping piece 93 and the second clamping piece 323 are formed into a circular shape coaxial with the operating rod 9, the diameter D11 of the first clamping piece 93 is larger than the diameter D of the second clamping piece 323, and the surface of the first clamping piece 93 facing the diaphragm member 34 is a convex spherical surface 94, which is formed in a manner of bulging toward the side of the diaphragm member 34 and has a center on the axis CL of the operating rod 9.

[0050] (2) In the fluid control valve 1 described in (1), the first radius of the convex spherical surface 94 is preferably smaller than the second radius of the spherical surface (facing surface 341 ) of the diaphragm member 34 facing the convex spherical surface 94 .

[0051] (3) In the fluid control valve 1 described in (2), it is preferable that the first radius is not less than 50% and not more than 65% of the second radius.

[0052] (4) In the fluid control valve 1 described in any one of (1) to (3), the diameter D11 of the first clamping piece 93 preferably exceeds 35% of the diameter D21 of the diaphragm member 34 when projected onto a plane perpendicular to the axis CL.

[0053] According to the aforementioned fluid control valve 1, when the valve core 32 is intended to contact the valve seat 33, the diaphragm member 34 begins to deform by being pressed downward toward the valve seat 33 from its apex, which is clamped between the first clamping piece 93 and the second clamping piece 323. During this deformation, the diaphragm member 34 deforms along the shape of the convex spherical surface 94 of the first clamping piece 93. Therefore, the contact area A11 between the convex spherical surface 94 and the diaphragm member 34 expands from the center toward the outer periphery of the diaphragm member 34 as the valve core 32 approaches the valve seat 33. The inventors of this application confirmed through finite element analysis that the stress concentration area in the diaphragm member 34 at this time is at the outermost periphery P11 of the contact area A11. In other words, when the valve is switched from an open state to a closed state, the stress concentration area in the diaphragm member 34 moves as the contact area A11 changes, and is not fixed. Therefore, even with repeated engagement and disengagement of the valve core 32, the diaphragm member 34 is less susceptible to damage. By making the diaphragm member 34 less susceptible to damage, the distance (stroke) between the open and closed positions of the valve core 32 can be increased compared to conventional valves. Increasing the stroke increases the distance between the valve core 32 and the valve seat 33 in the open state, thereby increasing the Cv value of the fluid control valve 1.

[0054] Furthermore, the above-mentioned embodiments are merely examples and do not limit the present invention in any way. Therefore, the present invention can of course be improved and deformed in various ways without departing from its main purpose. For example, the driving portion 2 of the fluid control valve 1 of this embodiment uses a pneumatically driven cylinder 6 as a driving source, but other driving sources such as an electric direct-acting motor can also be used. In addition, in this embodiment, the first clamping piece 93 and the operating rod 9 are formed as a whole in the form of the same component, but the first clamping piece and the operating rod 9 can also be set as different components. Similarly, the second clamping piece 323 and the valve core 32 are formed as a whole in the form of the same component, but the second clamping piece 323 and the valve core 32 can also be set as different components. Explanation of symbols

[0055] 1…Fluid control valve 9…operating lever 32…Spool 33…valve seat 34…Diaphragm member 93…1st clamping piece 94…convex sphere 323…Second clamping piece.

Claims

1. A fluid control valve comprising an operating rod, a valve element connected to the operating rod, a valve seat for the valve element to engage and disengage, and a diaphragm member located between the operating rod and the valve element, wherein the valve element driven by the operating rod engages and disengages along the axis of the operating rod to control the flow of a controlled fluid, wherein the fluid control valve is characterized in that: The center of the diaphragm member is located on the extension line of the axis, and the diaphragm member is formed into a spherical crown shape that bulges toward the operating rod side. The apex of the diaphragm member is clamped from both sides by a first clamping piece and a second clamping piece in a direction parallel to the axis. The first clamping piece contacts the diaphragm member from the operating rod side, and the second clamping piece contacts the diaphragm member from the valve core side. The first clamping piece and the second clamping piece are formed into a circular shape coaxial with the operating rod, and the diameter of the first clamping piece is larger than the diameter of the second clamping piece. The surface of the first holding piece facing the diaphragm member is a convex spherical surface. The convex spherical surface is formed so as to bulge toward the diaphragm member and has its center on the axis.

2. The fluid control valve according to claim 1, wherein: A first radius that is a radius of the convex spherical surface is smaller than a second radius that is a radius of a spherical surface of the diaphragm member that faces the convex spherical surface.

3. The fluid control valve according to claim 2, characterized in that: The first radius is not less than 50% and not more than 65% of the second radius.

4. The fluid control valve according to any one of claims 1 to 3, characterized in that: The diameter of the first clamping piece exceeds 35% of the diameter of the diaphragm member when projected onto a plane perpendicular to the axis.

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