Fluid control valve
The fluid control valve design addresses high-temperature diaphragm member issues by using a spherical crown diaphragm with distributed stress distribution, enhancing stroke amount and Cv value for improved productivity.
Patent Information
- Application Number
- JP2023105753
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-06-28
- Publication Date
- 2025-01-17
- Estimated Expiration
- 2043-06-28
AI Technical Summary
Fluid control valves used in semiconductor manufacturing face challenges with diaphragm members experiencing reduced self-returning force at high temperatures, leading to decreased Cv values and potential damage due to stress concentration, limiting stroke amount and productivity.
A fluid control valve design featuring a diaphragm member formed into a spherical crown shape, clamped by first and second holding pieces, with a convex spherical surface on the first holding piece to distribute stress and prevent damage, allowing for increased stroke amount and Cv value.
The design effectively prevents diaphragm member damage and increases stroke amount, enhancing the Cv value and productivity by distributing stress concentration, even at high temperatures.
Smart Images
Figure 2025005544000001_ABST
Abstract
Description
[Technical field]
[0001] The present invention relates to a fluid control valve comprising an operating rod, a valve body connected to the operating rod, a valve seat against which the valve body abuts and separates, and a diaphragm located between the operating rod and the valve body, in which the valve body, driven by the operating rod, abuts and separates along the axial direction of the operating rod, thereby controlling a control fluid. [Background technology]
[0002] A plurality of types of process gases are used in the film formation process in the semiconductor manufacturing process. A fluid control valve is used to control the flow rate of the process gas. For example, the fluid control valves disclosed in Patent Document 1 and Patent Document 2 are known as fluid control valves. The fluid control valve disclosed in Patent Document 1 is an air-operated on-off valve that controls the flow rate of the process gas by bringing a diaphragm member into contact with and separating from a valve seat.
[0003] More specifically, a stem (diaphragm retainer) is in contact with the apex of the diaphragm member formed in a spherical crown shape, and the actuator operates to press and deform the diaphragm member with the stem, causing it to abut against the valve seat. The state in which the diaphragm member abuts against the valve seat is the closed state of the fluid control valve. When the pressure on the diaphragm member by the stem is released, the self-restoring force of the diaphragm member causes it to return to its original spherical crown shape, and the diaphragm member moves away from the valve seat. The state in which the diaphragm member moves away from the valve seat is the open state of the fluid control valve. [Prior art documents] [Patent documents]
[0004] [Patent Document 1] JP 2016-180490 A [Patent Document 2] JP 2017-223318 A Summary of the Invention [Problem to be solved by the invention]
[0005] However, the process gas used in atomic layer deposition (ALD), a film formation technology that has become widespread in recent years, is high temperature (about 200 degrees), and at such high temperatures, the self-restoring force of the diaphragm member decreases, and when the fluid control valve is changed from a closed state to an open state, it may be difficult to return to the original spherical crown shape. If the diaphragm member does not return to the original spherical crown shape, the distance between the diaphragm member and the valve seat in the open state becomes small, and there is a concern that the Cv value will decrease. In order to shorten the semiconductor film formation process as much as possible and improve productivity, it is desired to increase the Cv value of the fluid control valve (i.e., to increase the amount of gas that can be flowed at one time), and the decrease in the Cv value due to the decrease in the self-restoring force of the diaphragm member as described above is not desirable.
[0006] Therefore, the inventors of the present application have come up with the idea of using a fluid control valve 100 as shown in FIG. 5, for example, as a countermeasure to the problem of the self-restoring force of the diaphragm member decreasing at high temperatures.
[0007] The fluid control valve 100 includes an actuator section 4, which includes a pneumatically driven air cylinder 6. A piston (not shown) is loaded inside the air cylinder 6 so as to be slidable in the vertical direction in FIG. 5. The piston moves up and down, thereby moving the operating rod 11 up and down. Furthermore, a valve body 32 that comes into contact with and moves away from a valve seat 33 as the operating rod 11 moves up and down is connected to the tip of the operating rod 11. The diaphragm member 34 is formed in a disk shape, and its outer periphery is clamped and fixed within the fluid control valve 100, while its center is clamped from the vertical direction in FIG. 5 by the clamping portion 111 of the operating rod 11 and the valve body 32.
[0008] In the above-described fluid control valve 100, when the valve disc 32 moves toward and away from the valve seat 33, deformation occurs in the diaphragm member 34 as shown in Fig. 6. Fig. 6 is a diagram showing the state of deformation of the diaphragm member 34 when the fluid control valve 100 shown in Fig. 5 moves from a valve open state to a valve closed state, where (a) represents the valve open state, (b) represents the state immediately after the valve disc starts to move in the abutting direction, and (c) represents the valve closed state.
[0009] When the fluid control valve 100 is in the open state, the diaphragm member 34 is in a state close to its natural state without deformation (FIG. 6(a)). Then, when the operating rod 11 is driven in the abutment direction to bring the valve body 32 into abutment against the valve seat 33, the diaphragm member 34 is deformed by being pushed down from the center portion sandwiched between the operating rod 11 (sandwiching portion 111) and the valve body 32 toward the valve seat 33 (see FIG. 5) (FIG. 6(b)). Then, when the valve body 32 abuts against the valve seat 33, i.e., when the fluid control valve 100 is in the closed state, the diaphragm member 34 is in the most deformed state (FIG. 6(c)).
[0010] To change the valve state from the closed state to the open state, the operating rod 11 is driven in the upward direction in the figure. As a result, the operating rod 11 and the valve body 32 move in the same direction, so that the valve body 32 moves away from the valve seat 33, and the fluid control valve 100 enters the open state. At this time, since the diaphragm member 34 is sandwiched between the operating rod 11 (sandwiching portion 111) and the valve body 32, the central portion is pulled up in the direction away from the valve seat 33, and the diaphragm member 34 can reliably return to its original shape as shown in FIG. 6(a). Therefore, it is possible to prevent the diaphragm member 34 from failing to return to its original shape even in a high-temperature environment, such as when a high-temperature process gas is used as the control fluid.
[0011] However, the above-described fluid control valve 100 has the following problems. The inventors of the present application discovered that, when the diaphragm member 34 is deformed as shown in Fig. 6, stress is concentrated at the portion P21 where the diaphragm member 34 is clamped. If the portion where the stress is concentrated on the diaphragm member 34 is always the same, when the valve body 32 of the fluid control valve 100 repeatedly comes into contact with and separates from the valve seat 33, the diaphragm member 34 may be damaged at the portion P21 where the stress is concentrated.
[0012] In addition, in recent years, there has been a demand for a high Cv value for the fluid control valve, and therefore, it is desired to increase the distance (stroke amount) between the valve open position and the valve closed position of the valve body from the conventional position. However, increasing the stroke amount increases the deformation amount of the diaphragm valve body. When the deformation amount increases, the diaphragm member 34 becomes more likely to break due to the concentration of stress at the above-mentioned portion P21. The stress concentration occurring in the diaphragm member 34 is the factor that makes it difficult to increase the stroke amount.
[0013] The present invention has been made in consideration of the above problems, and has an object to provide a fluid control valve capable of increasing the stroke amount. [Means for solving the problem]
[0014] In order to solve the above problems, a fluid control valve according to one aspect of the present invention has the following configuration.
[0015] (1) In a fluid control valve comprising an operating rod, a valve body connected to the operating rod, a valve seat against which the valve body comes into contact and separates, and a diaphragm member located between the operating rod and the valve body, the valve body being driven by the operating rod and performing the contact and separation along the direction of the axis of the operating rod, thereby controlling a control fluid, the diaphragm member is formed in a spherical crown shape whose center is located on an extension of the axis and which bulges out toward the operating rod, and at its apex, the diaphragm is extended from the operating rod side. The valve is clamped from both sides in a direction parallel to the axis by a first clamping piece that contacts the ram member and a second clamping piece that contacts the diaphragm member from the valve body side; the first clamping piece and the second clamping piece are formed in a circular shape positioned coaxially with the operating rod, the diameter of the first clamping piece is larger than the diameter of the second clamping piece; and the surface of the first clamping piece that faces the diaphragm member is formed to bulge toward the diaphragm member and is a convex spherical surface having its center on the axis.
[0016] (2) In the fluid control valve described in (1), it is preferable that 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 50 to 65% of the second radius.
[0018] (4) In the fluid control valve described in any one of (1) to (3), it is preferable that the diameter of the first clamping piece is greater than 35% of the diameter of the diaphragm member when projected onto a plane perpendicular to the axis of the diaphragm member.
[0019] According to the above-mentioned fluid control valve, when the valve body is to be brought into contact with the valve seat, the diaphragm member is deformed by being pushed down from the apex portion that is clamped by the first clamping piece and the second clamping piece toward the valve seat. During this deformation, the diaphragm member is deformed along the shape of the convex spherical surface of the first clamping piece, so that the contact area between the convex spherical surface and the diaphragm member expands from the center of the diaphragm member to the outer periphery as the valve body approaches the valve seat. The inventor of the present application confirmed by finite element analysis that the place where stress is concentrated in the diaphragm member is the outermost periphery of the contact area at this time. In other words, when changing from the valve open state to the valve closed state, the place where stress is concentrated in the diaphragm member moves in accordance with the change in the contact area and is not constant, so that the diaphragm member is not easily damaged even if the valve body is repeatedly brought into contact with and separated from the valve seat. By making the diaphragm member less likely to be damaged in this way, it is possible to increase the distance (stroke amount) between the position of the valve body in the valve open state and the position of the valve closed state more than before. If the stroke amount can be increased, the distance between the valve body and the valve seat becomes larger when the valve is open, and the Cv value of the fluid control valve becomes larger. Effect of the Invention
[0020] According to the fluid control valve of the present invention, it is possible to increase the stroke amount. [Brief description of the drawings]
[0021] [Figure 1] 1 is a cross-sectional view of a fluid control valve according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a partially enlarged view of a portion A in FIG. [Diagram 3] FIG. 2 is a perspective view of a diaphragm member. [Figure 4] 1A and 1B are diagrams showing the deformation of the diaphragm member when the fluid control valve of this embodiment changes from an open state to a closed state, in which (a) shows the open state, (b) shows the valve body immediately after it starts to move in the abutment direction, and (c) shows the closed state. [Diagram 5]1 is a cross-sectional view of a fluid control valve invented by the present inventor as a solution to the problem of a decrease in the self-returning force of a diaphragm member at high temperatures. [Figure 6] 6A and 6B are diagrams showing deformation of the diaphragm member when the fluid control valve shown in FIG. 5 changes from an open state to a closed state, in which (a) shows the open state, (b) shows the valve element immediately after starting to move in the contact direction, and (c) shows the closed state. [Figure 7] 10 is a graph showing the relationship between the amount of movement of the valve disc in the abutment direction from a position in a valve open state and the stress generated in a diaphragm member. [Figure 8] 4 is a graph showing the relationship between the stroke amount and the Cv value when the valve disc is at a high temperature. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] An embodiment of a fluid control valve according to the present invention will be described in detail with reference to the drawings. Note that the drawings used in the description are simplified for the purpose of explanation and do not accurately represent the shape, dimensions, etc.
[0023] (Configuration of the fluid control valve) The configuration of a fluid control valve 1 according to this embodiment will be described with reference to the drawings. Fig. 1 is a cross-sectional view of the fluid control valve 1 according to this embodiment. Fig. 2 is a partially enlarged view of a portion A in Fig. 1. Fig. 3 is a perspective view of a diaphragm member 34.
[0024] The fluid control valve 1 is a pneumatically driven gas valve disposed in a gas supply system of a semiconductor manufacturing device, and as shown in Fig. 1, is made up of a drive unit 2 and a valve unit 3. The drive unit 2 further comprises an actuator unit 4 and a spring unit 5.
[0025] First, a description will be given of the actuator section 4. The actuator section 4 includes an air cylinder 6 that is pneumatically driven, and a connection bracket 7 for connecting the air cylinder 6 and the spring section 5.
[0026] The air cylinder 6 includes a cylindrical case 61, a piston (not shown) that is loaded inside the case 61, and a columnar drive shaft (not shown) that is connected to the piston. The piston is slidable in the vertical direction in FIG. 1 inside the case 61, and the drive shaft advances and retreats along its axial direction in accordance with the vertical movement of the piston. The axial direction of the drive shaft is parallel to the vertical direction in FIG. 1 and coincides with the direction in which a valve body 32, described later, contacts and separates from a valve seat 33. The upper side in the figure is the separation direction, and the lower side is the contact direction.
[0027] The tip of the drive shaft of the air cylinder 6 on the valve portion 3 side protrudes from the case 61 and is connected to a cylindrical operating rod 9 located coaxially with the drive shaft. Therefore, as the drive shaft of the air cylinder 6 advances and retreats, the operating rod 9 also advances and retreats along its axis CL (see FIG. 2).
[0028] The operating rod 9 is inserted through the spring portion 5 and extends from inside the connection bracket 7 to the valve portion 3. As shown in FIG. 2, the operating rod 9 has an expanded diameter portion 91 at a portion inserted into the valve portion 3, the expanded diameter portion 91 having a larger diameter than the portion inserted into the connection bracket 7 and the portion inserted into the spring portion 5, thereby forming a step portion 92. Furthermore, the operating rod 9 has a first clamping piece 93 at an end portion opposite to the step portion 92 of the expanded diameter portion 91. The first clamping piece 93 is used to clamp a diaphragm member 34 described later together with a second clamping piece 323 described later. The first clamping piece 93 has a circular shape with a radial direction perpendicular to the axis CL of the operating rod 9, and is located coaxially with the axis CL. The diameter D11 of the first clamping piece 93 is larger than the diameter of the expanded diameter portion 91. Moreover, the surface of the first clamping piece 93 facing the diaphragm member 34 is a convex spherical surface 94 formed to bulge towards the diaphragm member 34. The center of the convex spherical surface 94 is located on the axis CL of the operating rod 9, and the radius (first radius) is set to, for example, approximately 70 mm. Moreover, the outer circumferential edge of the convex spherical surface 94 is subjected to R-chamfering.
[0029] Further, an internal thread 95 is drilled in the end face of the operating rod 9 on the valve portion 3 side, so that a valve body 32, which will be described later, can be screwed thereto.
[0030] Next, the spring section 5 will be described. The spring section 5 includes a compression coil spring 52 located coaxially with the operating rod 9 in an internal space 51. The compression coil spring 52 is compressed by an end face 53 on the actuator section 4 side of the internal space 51 and a step section 92 of the operating rod 9. Therefore, the compression coil spring 52 always biases the operating rod 9 in the contact direction (downward in the figure).
[0031] Next, the valve portion 3 will be described. The valve portion 3 includes a body 31, a valve element 32, a valve seat 33, and a diaphragm member 34. The body 31 includes a cylindrical portion 315 that is connected to the spring portion 5. Furthermore, the body 31 includes a valve chamber 311 formed inside the cylindrical portion 315.
[0032] The valve chamber 311 communicates with an input flow passage 313 through a valve port 312 at the center of the bottom. This input flow passage 313 is used to input a process gas into the valve chamber 311. A circular valve seat 33 is fixed to the bottom surface of the valve chamber 311 on the outer circumferential side of the valve port 312 and coaxially with the valve port 312. The valve seat 33 is made of a material such as PI (polyimide) or PFA (tetrafluoroethylene-perfluoroalkylvinylether copolymer), which has excellent heat resistance. Furthermore, the valve chamber 311 communicates with an output flow passage 314 on the radially outer side of the valve seat 33. This output flow passage 314 is used to output the process gas from the valve chamber 311.
[0033] The valve body 32 is made of, for example, stainless steel. The valve body 32 includes a cylindrical main body 321 and further includes a male thread portion 322 on the operating rod 9 side of the main body 321. The valve body 32 is connected to the operating rod 9 by screwing the male thread portion 322 into the female thread portion 95 of the operating rod 9.
[0034] The valve body 32 is provided with a second clamping piece 323 on the side opposite to the male threaded portion 322 of the main body 321. The second clamping piece 323 is circular in shape with a radial direction perpendicular to the axis CL of the operating rod 9, and is positioned coaxially 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. The second clamping piece 323 clamps the diaphragm member 34 together with the first clamping piece 93 from above and below in FIG. 2 by connecting the valve body 32 to the operating rod 9. The surface of the second clamping piece 323 facing the diaphragm member 34 is flat, and the outer circumferential edge of the flat surface is R-chamfered.
[0035] Furthermore, the valve body 32 is provided with an abutment portion 324 that abuts against and separates from the valve seat 33 on the side opposite to the main body portion 321 side of the second clamping piece 323. This abutment portion 324 is also circular and located coaxially with the axis CL of the operating rod 9. Since the valve body 32 is connected to the operating rod 9, the abutment portion 324 abuts against and separates from the valve seat 33 along the direction of the axis CL as the operating rod 9 advances and retreats.
[0036] The diaphragm member 34 is made of, for example, a Ni alloy. The center of the diaphragm member 34 is located on an extension of the axis CL, and the diaphragm member 34 is formed in a spherical crown shape that bulges toward the operating rod 9. Therefore, the facing surface 341 facing the convex spherical surface 94 of the diaphragm member 34 is a spherical surface. The radius (second radius) of the sphere of the facing surface 341 is set to, for example, about 140 mm. The surface on the back side of the facing surface 341 is referred to as a back surface 342. A cut 343 is provided at the apex of the diaphragm member 34 (facing surface 341). This cut 343 is circular in shape with a radial direction perpendicular to the axis CL, and is located coaxially with the axis CL. The outer periphery of the facing surface 341 is provided with a flat edge 344 perpendicular to the axis CL. This edge 344 is circular in shape with a radial direction perpendicular to the axis CL.
[0037] The diaphragm member 34 as described above is fixed inside the fluid control valve 1 as follows. The male threaded portion 322 of the valve body 32 is inserted into the cut 343 of the diaphragm member 34 from the side opposite to the opposing surface 341, and the diaphragm member 34 and the valve body 32 are positioned coaxially with the back surface 342 of the diaphragm member 34 in contact with the second clamping piece 323 of the valve body 32. Then, the male threaded portion 322 is screwed into the female threaded portion 95 of the operating rod 9 until the convex spherical surface 94 of the first clamping piece 93 contacts the spherical surface 341 of the diaphragm member 34. As a result, the diaphragm member 34 is clamped from both sides in the direction of the axis CL (the vertical direction in the figure) by the first clamping piece 93 and the second clamping piece 323 at the edge of the cut 343, as shown in FIG. 1 or FIG. 2. That is, the operating rod 9 and the diaphragm member 34 are coupled together. 1 or 2, the edge portion 344 of the diaphragm member 34 is clamped and fixed from above and below within the valve portion 3. By being fixed inside the fluid control valve 1 as described above, the diaphragm member 34 divides the inside of the cylindrical portion 315 of the body 31 into the valve chamber 311 and an upper portion thereof, and is adapted to repeatedly undergo elastic deformation as the valve body 32 moves in the direction of contact and separation.
[0038] (Operation of the fluid control valve) The operation of changing the fluid control valve 1 from the valve open state to the valve closed state will be described. When operating air is supplied to the air cylinder 6, the fluid control valve 1 is in the valve open state as shown in FIG. 1. As described above, the operating rod 9 is always biased in the direction of contact with the compression coil spring 52, so the valve open state is a state in which the actuator unit 4 pulls the operating rod 9 upward in the figure against the biasing force of the compression coil spring 52. To change from this state to the valve closed state, the supply of operating air to the air cylinder 6 is stopped. Then, the biasing force of the compression coil spring 52 presses the operating rod 9 and the valve body 32 down toward the valve seat 33, and the abutment portion 324 of the valve body 32 abuts against the valve seat 33.
[0039] Next, the deformation occurring in the diaphragm member 34 when the valve is changed from the open state to the closed state as described above will be described with reference to Fig. 4. Fig. 4 is a diagram showing the deformation of the diaphragm member 34 when the fluid control valve 1 according to this embodiment changes from the open state to the closed state, where (a) shows the valve open state, (b) shows the valve element 32 immediately after starting to move in the contact direction, and (c) shows the closed state.
[0040] When the fluid control valve 1 is in the open state, the diaphragm member 34 is in a state close to its natural state without deformation (FIG. 4(a)). Then, when the operating rod 9 is driven in the abutment direction and the valve body 32 is about to abut against the valve seat 33, the diaphragm member 34 is deformed by being pushed down from the center portion sandwiched between the first clamping piece 93 and the second clamping piece 323 toward the valve seat 33 (see FIG. 2) (FIG. 4(b)). Then, when the valve body 32 abuts against the valve seat 33, that is, when the fluid control valve 1 is in the closed state, the diaphragm member 34 is in the most deformed state (FIG. 4(c)). During this deformation, the diaphragm member 34 deforms along the shape of the convex spherical surface 94, so that the contact area A11 between the convex spherical surface 94 of the first clamping piece 93 and the opposing surface 341 of the diaphragm member 34 expands from the center toward the outer periphery as the valve body 32 approaches the valve seat 33 (Figures 4(b) and (c)).
[0041] The inventors of the present application confirmed by finite element analysis that the location where stress concentrates when the diaphragm member 34 deforms as described above is the outermost periphery P11 of the contact range A11. In other words, when changing from the valve open state to the valve closed state, the location where stress concentrates in the diaphragm member 34 moves in accordance with the fluctuation of the contact range A11 and is not constant, so that the diaphragm member 34 is less likely to be damaged even if the valve body 32 is repeatedly brought into contact with and separated from the valve body 32. By making the diaphragm member 34 less likely to be damaged in this way, it is possible to increase the distance (stroke amount) between the position of the valve body 32 in the valve open state and the position of the valve closed state compared to the conventional case. If the stroke amount can be increased, the distance between the valve body 32 and the valve seat 33 becomes larger in the valve open state, and the Cv value of the fluid control valve 1 becomes larger.
[0042] 4(b) and (c), in order to deform diaphragm member 34 along the shape of convex spherical surface 94, it is desirable that the radius of convex spherical surface 94 be 50 to 65% of the radius of spherical surface 341. In this embodiment, the radius (first radius) of convex spherical surface 94 is approximately 70 mm, while the radius (second radius) of opposing surface 341 of diaphragm member 34 is approximately 140 mm.
[0043] Furthermore, by making the diameter D11 of the first clamping piece 93 as large as possible, a larger stroke amount can be ensured. Specifically, it is desirable that the diameter D11 (see FIG. 2) of the first clamping piece 93 is a value exceeding 35% of the diameter D21 (see FIG. 3) of the diaphragm member 34. Note that 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, the diameter of the edge portion 344 in this embodiment.
[0044] Specifically, the description will be given with reference to Figs. 7 and 8. Fig. 7 is a graph showing the relationship between the amount of movement (stroke amount) of the valve body 32 in the abutment direction from the position in the valve open state (hereinafter referred to as the valve open position) and the stress generated in the diaphragm member, and compares the case where the diameter D11 of the first clamping piece 93 is 35% of the diameter D21 of the diaphragm member 34, the case where the diameter D11 is 65% of the diameter D21, and the case where the diameter D21 is 85% of the diameter D21. The waveform shown by the dashed dotted line in Fig. 7 is the waveform when the diameter D11 is 35% of the diameter D21. Note that the fact that the diameter D11 is 35% of the diameter D21 is the same as the relationship between the diameter of the clamping part 111 and the diameter of the diaphragm member 34 in the fluid control valve 100 shown in Fig. 5. The waveform shown by the solid line in Fig. 7 is the waveform when the diameter D11 is 65% of the diameter D21. The broken line waveform in Fig. 7 is the waveform when the diameter D11 is 85% of the diameter D21. The rising parts of each waveform indicate the occurrence of stress concentration to the extent that the diaphragm member 34 is broken. Fig. 8 is a graph showing the relationship between the stroke amount and the Cv value when the valve body 32 is at a high temperature. It is shown 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 rise in the waveform is observed when the amount of movement of the valve body 32 reaches S1 (see FIG. 7). In other words, when the amount of movement of the valve body 32 reaches S1, stress concentration occurs to the extent that the diaphragm member 34 is broken. Therefore, the stroke amount can be secured at a maximum of S1. When the stroke amount is secured at S1, the Cv value of the fluid control valve 1 (fluid control valve 100) is C1 (see FIG. 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, the waveform rises when the movement amount of the valve body 32 reaches S2 (see FIG. 7). In other words, when the movement amount of the valve body 32 reaches S2, stress concentration occurs to the extent that the diaphragm member 34 is broken. Therefore, the stroke amount can be secured to a maximum of 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 (see FIG. 8). This is about 1.5 times the Cv value when the diameter D11 is set to 35% of the diameter D21.
[0047] Also, 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, the rising edge of the waveform is observed when the movement amount of the valve body 32 reaches S3 (see FIG. 7). In other words, when the movement amount of the valve body 32 reaches S3, a stress is generated that is enough to cause the diaphragm member 34 to break. Therefore, the stroke amount can be secured to a maximum of 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 (see FIG. 8). This is about 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 is a value exceeding 35% of the diameter D21 of the diaphragm member 34, it is possible to delay the rise of the waveform compared to when the diameter D11 is 35% of the diameter D21, as shown in Fig. 7. In other words, it is possible to move the valve body 32 more, that is, it is possible to increase the stroke amount. Note that it is desirable for the diameter D11 of the first clamping piece 93 to be as large as possible within the scope of the structure of the fluid control valve 1, but in reality, it is smaller than the diameter D21 of the diaphragm member 34.
[0049] As described above, the fluid control valve 1 according to this embodiment includes (1) an operating rod 9, a valve body 32 connected to the operating rod 9, a valve seat 33 against which the valve body 32 comes into contact and separates, and a diaphragm member 34 located between the operating rod 9 and the valve body 32. In the fluid control valve 1 in which the valve body 32 driven by the operating rod 9 comes into contact with and separates from the valve body 32 along the direction of the axis CL of the operating rod 9, the center of the diaphragm member 34 is located on an extension of the axis CL and is formed in a spherical crown shape that bulges out toward the operating rod 9, and its apex (cutout 343) is in contact with the side of the operating rod 9. the first clamping piece 93 and the second clamping piece 323 are formed in a circular shape positioned coaxially with the operating rod 9, and a diameter D11 of the first clamping piece 93 is larger than a diameter D of the second clamping piece 323; and the surface of the first clamping piece 93 facing the diaphragm member 34 is formed to bulge towards the diaphragm member 34, and is a convex spherical surface 94 having a center on the axis CL of the operating rod 9.
[0050] (2) In the fluid control valve 1 described in (1), it is preferable that the first radius, which is the radius of the convex spherical surface 94, is smaller than the second radius, which is the radius of the spherical surface (opposing surface 341) facing the convex spherical surface 94 of the diaphragm member 34.
[0051] (3) In the fluid control valve 1 described in (2), the first radius is preferably 50 to 65% of the second radius.
[0052] (4) In the fluid control valve 1 described in any one of (1) to (3), it is preferable that the diameter D11 of the first clamping piece 93 is a value exceeding 35% of the diameter D21 when projected onto a plane perpendicular to the axis CL of the diaphragm member 34.
[0053] According to the above-mentioned fluid control valve 1, when the valve body 32 is brought into contact with the valve seat 33, the diaphragm member 34 is deformed by being pushed down toward the valve seat 33 from the apex portion sandwiched between the first sandwiching piece 93 and the second sandwiching piece 323. During this deformation, the diaphragm member 34 deforms along the shape of the convex spherical surface 94 of the first sandwiching piece 93, so that the contact area A11 between the convex spherical surface 94 and the diaphragm member 34 expands from the center of the diaphragm member 34 to the outer periphery side as the valve body 32 approaches the valve seat 33. The inventors of the present application have confirmed by finite element analysis that the location where stress is concentrated in the diaphragm member 34 is the outermost periphery P11 of the contact area A11. In other words, when changing from the valve open state to the valve closed state, the point where stress is concentrated in the diaphragm member 34 moves in accordance with the fluctuation of the contact range A11 and is not constant, so that the diaphragm member 34 is less likely to be damaged even if the valve element 32 is repeatedly brought into and out of contact with the valve. By making the diaphragm member 34 less likely to be damaged in this way, it is possible to increase the distance (stroke amount) between the position of the valve element 32 in the valve open state and the position of the valve closed state compared to the conventional case. If the stroke amount can be increased, the distance between the valve element 32 and the valve seat 33 becomes larger in the valve open state, and the Cv value of the fluid control valve 1 becomes larger.
[0054] The above embodiment is merely an example and does not limit the present invention. Therefore, the present invention can be improved and modified in various ways without departing from the scope of the present invention. For example, the driving unit 2 of the fluid control valve 1 according to the present embodiment uses the pneumatically driven air cylinder 6 as a driving source, but other driving sources such as an electric direct-acting motor may be used. In the present embodiment, the first clamping piece 93 and the operating rod 9 are integrally formed as the same member, but the first clamping piece and the operating rod 9 may be separate members. Similarly, the second clamping piece 323 and the valve body 32 are integrally formed as the same member, but the second clamping piece 323 and the valve body 32 may be separate members. [Explanation of symbols]
[0055] 1. Fluid control valve 9 Operating rod 32 Valve body 33 Valve seat 34 Diaphragm member 93 1st clamping piece 94 Convex spherical surface 323 Second clamping piece
Claims
1. A fluid control valve comprising: an operating rod; a valve body connected to the operating rod; a valve seat against which the valve body comes into contact and separates; and a diaphragm member located between the operating rod and the valve body, wherein the valve body, which is driven by the operating rod, comes into contact and separates along an axial direction of the operating rod, thereby controlling a control fluid, the diaphragm member has a center located on an extension of the axis, is formed in a spherical crown shape that bulges toward the operating rod, and is sandwiched at its apex from both sides in a direction parallel to the axis by a first sandwiching piece that contacts the diaphragm member from the operating rod side and a second sandwiching piece that contacts the diaphragm member from the valve body side; The first clamping piece and the second clamping piece are formed in a circular shape coaxially with the operating rod, and the diameter of the first clamping piece is larger than the diameter of the second clamping piece; a surface of the first clamping piece facing the diaphragm member is formed to bulge toward the diaphragm member and is a convex spherical surface having a center on the axis; A fluid control valve comprising:
2. 2. The fluid control valve according to claim 1, 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; A fluid control valve comprising:
3. 3. The fluid control valve according to claim 2, the first radius being 50-65% of the second radius; A fluid control valve comprising:
4. 4. The fluid control valve according to claim 1, The diameter of the first clamping piece is a value exceeding 35% of the diameter of the diaphragm member when projected onto a plane perpendicular to the axis of the diaphragm member; A fluid control valve comprising:
Citation Information
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