regulator

Abstract

To provide a regulator capable of preventing dust generation at a contact part between a valve body and a diaphragm member.SOLUTION: A receiving part 151a of a diaphragm member 15 that receives a tip surface of a shaft part 145 of a valve body 14 has, at a portion facing the tip surface, a concave spherical surface 151b formed by a first radius whose center is located on a central axis CL11 of the shaft part 145. The first radius is equal to or larger than a value obtained by subtracting 20% of a value of a diameter D11 from the value of the diameter D11 of the shaft part 145. A portion of the tip surface facing the concave spherical surface 151b has a convex spherical surface 144 formed by a second radius that is a value obtained by subtracting 2 to 5% of a value of the first radius from the value of the first radius.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a regulator. [Background technology]

[0002] Conventionally, in semiconductor manufacturing processes, regulators such as those disclosed in Patent Document 1 have been used to control the pressure of control fluids such as pure water and chemical liquids used in wafer film formation processes. A regulator according to the prior art will be described with reference to FIG. 28. FIG. 28 is a cross-sectional view of a regulator 50 according to the prior art.

[0003] In the regulator 50, an input port 59, an upstream fluid chamber 52, a valve hole 54, a downstream fluid chamber 53, and an output port 60 are connected in this order from the upstream side, forming a series of flow paths.

[0004] A valve element 51 is housed in the upstream fluid chamber 52. The valve element 51 is movable in the vertical direction in the figure, and comes into contact with and separates from an annular valve seat 55 provided along the outer periphery of the valve hole 54.

[0005] A compression coil spring 58 is disposed at the lower end of the valve element 51 in the drawing, and the biasing force of this compression coil spring 58 biases the valve element 51 in a direction (closing direction) toward contact with the annular valve seat 55. The valve element 51 also has a cylindrical shaft portion 511 that extends from the upstream fluid chamber 52, through the valve hole 54, to the downstream fluid chamber 53 along the contact / separation direction. A tip surface 512 of this shaft portion 511 is formed as a convex spherical surface with substantially the same diameter as the shaft portion 511. The shaft portion 511 is loosely fitted in a receiving portion 571 of a diaphragm member 57 housed in the downstream fluid chamber 53 so as to be separable. The receiving portion 571 of the diaphragm member 57 is formed as a concave spherical surface with substantially the same diameter as the shaft portion 511.

[0006] The diaphragm member 57 is capable of changing its position along the direction of contact and separation in response to the pressure of the operating air supplied to the pressure application chamber 56 .

[0007] The regulator 50 configured as described above is capable of adjusting the distance (i.e., opening) of the valve element 51 from the annular valve seat 55 by balancing the pressure of the operating air supplied to the pressure application chamber 56 and the biasing force of the compression coil spring 58.

[0008] Here, the fact that the valve element 51 is loosely fitted into the diaphragm member 57 so as to be separable will be described in detail. For example, when back pressure from the output port 60 side is applied and the pressure in the downstream fluid chamber 53 suddenly increases, the diaphragm member 57 is pushed upward in the figure (i.e., in the closing direction). At this time, if the valve element 51 and the diaphragm member 57 are connected so as not to be separated, as the diaphragm member 57 is pushed upward in the closing direction, the valve element 51 may move in the closing direction and interfere excessively with the annular valve seat 55. Excessive interference between the valve element 51 and the annular valve seat 55 is not desirable because it can cause particles to be generated due to wear, etc.

[0009] Therefore, if the valve element 51 and the diaphragm member 57 are made separable, even if the pressure in the downstream fluid chamber 53 suddenly increases and the diaphragm member 57 is pushed up in the closing direction, the diaphragm member 57 will separate from the valve element 51 and move independently in the closing direction. This prevents the valve element 51 from moving in the closing direction, making it possible to prevent excessive interference with the annular valve seat 55. Note that the valve element 51 and the diaphragm member 57 are wetted members that come into contact with the control fluid, and are therefore made of a highly corrosion-resistant fluorine-based synthetic resin (for example, PTFE or PFA). [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Patent Publication No. 2021-89070 Summary of the Invention [Problem to be solved by the invention]

[0011] However, the above-described regulator has the following problem: As described above, when valve element 51 is loosely fitted in diaphragm member 57 so as to be separable, tip surface 512 of shaft portion 511 and receiving portion 571 of diaphragm member 57 repeatedly come into contact with and separate from each other, which may result in the generation of dust.

[0012] The cause of this dust generation is thought to be that when tip surface 512 and receiving portion 571 come into contact with each other, excessive stress is generated at the contact surface, or slippage occurs on tip surface 512.

[0013] First, we will explain the stress generated at the contact surface when the tip surface 512 and the receiving portion 571 come into contact. Figure 29 shows the results of a finite element analysis of the stress generated at the contact surface between the valve body 51 and the diaphragm member 57 (the contact surface between the tip surface 512 and the receiving portion 571) in the prior art. This analysis assumes that both the valve body 51 and the diaphragm member 57 are made of PTFE and that the tip surface 512 is pressed against the receiving portion 571 by the biasing force of the compression coil spring 58. The length and color density of the color bar represent the value of the generated stress. In other words, the longer the length of the color bar, the greater the generated stress, and the darker the color bar, the greater the generated stress.

[0014] The generated stress increases toward the central axis CL51 of the stem portion 511 and reaches a maximum near the center of the stem portion 511. This maximum stress value is 10.92 MPa. The compressive strength of PTFE is approximately 10 MPa, and is thought to be approximately 5 MPa in a high-temperature atmosphere (e.g., 90°C, the temperature of the control fluid). This analysis result indicates that when the tip surface 512 of the valve body 51 and the receiving portion 571 of the diaphragm member 57 are in contact, stress equal to or greater than the compressive strength of the material acts. Therefore, repeated contact and separation between the tip surface 512 and the receiving portion 571 may cause plastic deformation of the stem portion 511 and the receiving portion 571. The occurrence of plastic deformation may cause damage to the contact surface between the valve body 51 and the diaphragm member 57 and lead to dust generation.

[0015] Next, we will explain the slippage of the tip surface 512 that occurs when the tip surface 512 and the receiving portion 571 come into contact. Figure 30 shows the results of a finite element analysis of the slippage of the tip surface 512 of the stem portion 511 in the prior art. Similar to the stress analysis described above, both the valve element 51 and the diaphragm member 57 are made of PTFE, and the tip surface 512 is assumed to be pressed against the receiving portion 571 by the biasing force of the compression coil spring 58. The length and color density of the color bar indicate the amount of slippage. That is, the longer the color bar, the greater the amount of slippage, and the darker the color bar, the greater the amount of slippage. The direction in which the color bar extends indicates the direction of slippage, and the color bar extending toward the stem portion 145 indicates the occurrence of slippage toward the center axis CL51 (inward slippage).

[0016] As shown in Figure 30, the slippage that occurs is generally inward slippage. The amount of slippage increases with increasing distance from the central axis CL51, reaching a maximum value near the midpoint between the central axis CL51 and the outer periphery of the shaft portion 511. After passing this maximum value, the amount of slippage decreases toward the outer periphery. The range of the amount of slippage that occurs is 0 to 2.9 µm.

[0017] If slippage occurs in this manner, the distal end surface 512 and the receiving portion 571 may repeatedly come into contact with and separate from each other, which may result in repeated sliding between the distal end surface 512 and the receiving portion 571. The repeated sliding may cause dust to be generated at the contact surface between the valve body 51 and the diaphragm member 57.

[0018] Dust generated at the contact surface between the valve body 51 and the diaphragm member 57 can cause particles to be mixed into the control fluid. If particles are mixed into the control fluid, there is a risk that the efficiency of semiconductor manufacturing will decrease, such as causing wafer manufacturing defects.

[0019] The present invention has been made in view of the above problems, and has as its object to provide a regulator capable of preventing the generation of dust at the contact portion between the valve body and the diaphragm member. [Means for solving the problem]

[0020] In order to solve the above problems, a regulator according to one aspect of the present invention has the following configuration.

[0021] (1) A valve device comprising: an upstream fluid chamber in which a valve element is accommodated; a downstream fluid chamber located downstream of the upstream fluid chamber; a valve hole that connects the upstream fluid chamber and the downstream fluid chamber; an annular valve seat that is provided along the outer periphery of the valve hole and against which the valve element comes into contact and separates; and a diaphragm member that is accommodated in the downstream fluid chamber and changes its position in a contact / separation direction in response to a pressure of operating air, wherein the valve element has a cylindrical shaft portion that extends from the upstream fluid chamber through the valve hole to the downstream fluid chamber along the contact / separation direction, and the shaft portion is a cylindrical member that is attached to the diaphragm portion. a regulator in which the valve element is loosely fitted into a receiving part that receives the tip end surface of the shank of a member made of a material, and a biasing means is disposed on the opposite side of the diaphragm member of the valve element to apply a biasing force to the valve element in a direction in which the valve element abuts against the annular valve seat, and the opening of the valve element is adjusted by the balance between the pressure of the operating air and the biasing force; the receiving part has a concave spherical surface formed by a first radius whose center is located on the central axis of the shank at a portion facing the tip end surface, and the first radius is equal to or greater than the value obtained by subtracting 20% ​​of the value of the diameter from the value of the diameter of the shank; And, The portion of the tip surface facing the concave spherical surface is a convex spherical surface formed by a second radius that is the value of the first radius minus 2-5% of the value of the first radius. and suppressing slippage of the convex spherical surface at the contact surface between the concave spherical surface and the convex spherical surface. It is characterized by:

[0022] According to the regulator, the first radius is equal to or greater than the diameter of the shaft portion minus 20% of the diameter, so that the stress generated on the contact surface when the valve body and the diaphragm member come into contact can be suppressed to 10 MPa or less. For example, highly corrosion-resistant materials such as PTFE and PFA are selected for the valve body and diaphragm members, with the compressive strength of PTFE being approximately 10 MPa and that of PFA being approximately 15 MPa. Even if PTFE, which has a lower compressive strength, is selected, as described above, the stress generated at the contact surface can be kept below 10 MPa, making it possible to prevent plastic deformation of the valve body and diaphragm members, and ultimately damage and dust generation.

[0023] Furthermore, with the regulator, the first radius is equal to or greater than the diameter of the stem minus 20% of the diameter, so the maximum amount of slippage of the stem at the contact surface between the valve body and the diaphragm member can be reduced to 30% or less of the conventional amount. Reducing the amount of slippage of the stem compared to the conventional amount makes it possible to reduce dust generation.

[0024] As described above, if the stress and slippage occurring on the contact surface can be reduced, the risk of dust generation on the contact surface can be reduced, which in turn can prevent particles from being mixed into the control fluid and, ultimately, prevent a decrease in semiconductor manufacturing efficiency.

[0025] (2) In the regulator described in (1), it is preferable that the first radius is equal to or less than the diameter of the shaft portion plus 20% of the diameter, thereby reliably suppressing the stress generated at the contact surface between the valve body and the diaphragm member to 10 MPa or less, and preventing plastic deformation of the valve body and the diaphragm member, and therefore damage and dust generation.

[0026] (3) In the regulator described in (2), it is preferable that the first radius is equal to or greater than the diameter of the stem portion minus 10% of the diameter and equal to or less than the diameter of the stem portion plus 10% of the diameter. This makes it possible to suppress the stress generated at the contact surface when the valve disc and the diaphragm member come into contact to 5 MPa or less. The compressive strength of PTFE is thought to be approximately 5 MPa in a high-temperature atmosphere (e.g., 90°C, the temperature of the control fluid). By suppressing the stress generated at the contact surface when the valve disc and the diaphragm member come into contact to 5 MPa or less, it is possible to prevent plastic deformation of the valve disc and the diaphragm member, and therefore damage and dust generation, even in a high-temperature atmosphere.

[0027] (4) In the regulator described in any one of (1) to (3), the second radius is preferably the first radius minus 3-4% of the first radius. This reliably reduces stress on the contact surface between the valve element and the diaphragm member. For example, if the second radius is greater than the first radius minus 2% of the first radius, the degree of freedom of the valve element's stem within the diaphragm member's receiving portion is reduced. If the valve element tilts during opening or closing, the tilt cannot be absorbed, and excessive stress may be generated on the contact surface. On the other hand, if the second radius is smaller than the first radius minus 4% of the first radius, the valve element's stem may not fully contact the diaphragm member's receiving portion, causing the central axis of the stem to deviate. Therefore, as described above, the second radius is preferably the first radius minus 3-4% of the first radius.

[0028] In the above regulator, the entire tip surface of the shaft portion may be a convex spherical surface. (5) In the regulator described in (1), the receiving portion may have a concave curved surface formed on the outer periphery of the concave spherical surface with a radius smaller than the first radius and tangent to the concave spherical surface, and the tip surface may have a convex curved surface formed on the outer periphery of the convex spherical surface and facing the concave curved surface with a radius smaller than the second radius and tangent to the convex spherical surface. Furthermore, in the regulator described in (6)(1), the receiving portion may have a first flat surface on the outer periphery of the concave spherical surface and on a tangent to the concave spherical surface, and the tip surface may have a second flat surface on the outer periphery of the convex spherical surface and on a tangent to the convex spherical surface at a portion facing the first flat surface.

[0029] (7) In the regulator described in any one of (1) to (6), it is preferable that the receiving portion has a cylindrical wall facing the outer peripheral surface of the shaft portion, that there is a gap between the cylindrical wall and the outer peripheral surface of the shaft portion, and that the size of the gap is 3-5% of the diameter of the shaft portion.

[0030] According to the regulator described in (7), the receiving portion has a cylindrical wall facing the outer peripheral surface of the shaft portion, so that the cylindrical wall can reliably prevent the axis of the shaft portion from becoming misaligned.

[0031] Furthermore, when the biasing force of the biasing means presses the shank against the receiving portion, the shank may be compressed, potentially causing deformation in the direction of increasing its diameter. However, according to the regulator described in (7), a gap is provided between the cylindrical wall and the outer peripheral surface of the shank, preventing interference between the shank and the cylindrical wall even when the shank is compressed and increases in diameter. Preventing interference prevents friction between the shank and the cylindrical wall, which could result in dust generation. The size of the gap is preferably 3-5% of the diameter of the shank. A gap larger than 5% of the diameter of the shank cannot reliably prevent the central axis of the shank from wobbling, while a gap smaller than 3% of the diameter of the shank may cause interference with the cylindrical wall when the shank is compressed and increases in diameter. Note that the "gap" here refers to the diameter of the cylindrical wall minus the diameter of the shank, assuming that the shank and the cylindrical wall are coaxially positioned, divided by 2.

[0032] (8) In the regulator described in any one of (1) to (7), a non-contact portion that does not contact the concave spherical surface is provided at the apex of the convex spherical surface, coaxial with the shaft portion, and the diameter of the non-contact portion does not exceed 1 / 20 of the diameter of the shaft portion.

[0033] The convex spherical surface is expected to be formed by cutting or injection molding. When the convex spherical surface is formed by cutting, the machining speed at the apex of the convex spherical surface is zero, which may result in burrs. Contacting the concave spherical surface with burrs may cause dust generation. Therefore, dust generation can be prevented by making the apex of the convex spherical surface a non-contact portion, as in the regulator described in (7). Furthermore, when the convex spherical surface is formed by injection molding, if a gate is located on the surface of the convex spherical surface, the effect of suppressing stress and slippage occurring at the contact surface when the valve body and the diaphragm member come into contact may be insufficient. Therefore, by making the apex of the convex spherical surface a non-contact portion, as in the regulator described in (7), the gate can be located in a non-contact portion that does not affect the above effect. However, it is desirable that the diameter of the non-contact portion does not exceed 1 / 20 of the diameter of the stem. If the diameter of the non-contact portion exceeds 1 / 20 of the diameter of the stem, the surface area of ​​the convex spherical surface becomes smaller, thereby insufficiently suppressing the above-mentioned effect of suppressing stress and slippage. [Effects of the Invention]

[0034] According to the regulator of the present invention, it is possible to prevent dust from being generated at the contact portion between the valve body and the diaphragm member. [Brief explanation of the drawings]

[0035] [Figure 1] FIG. [Figure 2] FIG. 2 is a partially enlarged view of a portion A in FIG. [Figure 3] FIG. 3 is a partially enlarged view of a portion B in FIG. [Figure 4] 5 is a diagram showing the results of a finite element analysis of the stress generated on the contact surface between the valve body and the diaphragm member in the first embodiment. FIG. [Figure 5] FIG. 4 is a diagram showing the results of a finite element analysis of slippage on the tip surface of the shaft in the first embodiment. [Figure 6]FIG. 10 is a diagram showing the results of a finite element analysis of the stress generated at the contact surface between the valve body and the diaphragm member in the first comparative example. [Figure 7] FIG. 10 is a diagram showing the results of a finite element analysis of slippage on the tip surface of the shaft portion in the first comparative example. [Figure 8] FIG. 10 is a diagram showing the results of a finite element analysis of the stress generated at the contact surface between the valve body and the diaphragm member in the second comparative example. [Figure 9] FIG. 10 is a diagram showing the results of a finite element analysis of slippage on the tip surface of the shaft portion in the second comparative example. [Figure 10] FIG. 10 is a diagram showing the results of a finite element analysis of the stress generated at the contact surface between the valve body and the diaphragm member in the third comparative example. [Figure 11] FIG. 10 is a diagram showing the results of a finite element analysis of slippage on the tip surface of the shaft portion in the third comparative example. [Figure 12] FIG. 10 is a diagram showing the results of a finite element analysis of the stress generated at the contact surface between the valve body and the diaphragm member in the fourth comparative example. [Figure 13] FIG. 10 is a diagram showing the results of a finite element analysis of slippage on the tip surface of the shaft portion in the fourth comparative example. [Figure 14] 10 is a graph comparing maximum stress values ​​obtained by finite element analysis. [Figure 15] 10 is a graph comparing the range of slippage amounts obtained by finite element analysis. [Figure 16] 10 is an enlarged view of a contact portion between a valve body and a diaphragm member in a second embodiment, and corresponds to FIG. 2. FIG. [Figure 17] FIG. 17 is a partially enlarged view of a portion C in FIG. [Figure 18] FIG. 10 is a diagram showing the results of a finite element analysis of the stress generated on the contact surface between the valve body and the diaphragm member in the second embodiment. [Figure 19] FIG. 10 is a diagram showing the results of a finite element analysis of slippage on the tip surface of the shaft in the second embodiment. [Figure 20] 10 is an enlarged view of a contact portion between a valve body and a diaphragm member in a third embodiment, and corresponds to FIG. 2. FIG. [Figure 21] FIG. 11 is a diagram showing the results of a finite element analysis of the stress generated on the contact surface between the valve body and the diaphragm member in the third embodiment. [Figure 22] FIG. 11 is a diagram showing the results of a finite element analysis of slippage on the tip surface of the shaft in the third embodiment. [Figure 23] 10 is an enlarged view of a contact portion between a valve body and a diaphragm member in a third embodiment, and corresponds to FIG. 2. FIG. [Figure 24] FIG. 10 is a diagram showing the results of a finite element analysis of the stress generated on the contact surface between the valve body and the diaphragm member in the fourth embodiment. [Figure 25] FIG. 10 is a diagram showing the results of a finite element analysis of slippage on the tip surface of the shaft in the fourth embodiment. [Figure 26] 10 is a graph comparing maximum stress values ​​obtained by finite element analysis in each configuration. [Figure 27] 10 is a graph comparing the range of slippage in each configuration based on finite element analysis. [Figure 28] FIG. 1 is a cross-sectional view of a regulator according to the prior art. [Figure 29] FIG. 10 is a diagram showing the results of a finite element analysis of stress occurring at the contact surface between a valve body and a diaphragm member in the prior art. [Figure 30] FIG. 10 is a diagram showing the results of a finite element analysis of slippage on the tip surface of a shaft portion in the prior art. [Figure 31] 5A and 5B are diagrams illustrating forces acting on the valve body and the diaphragm member when the valve body and the diaphragm member come into contact with each other in the first embodiment. [Figure 32] 10A and 10B are diagrams illustrating forces acting on a valve body and a diaphragm member when the valve body and the diaphragm member come into contact with each other in the prior art. DETAILED DESCRIPTION OF THE INVENTION

[0036] An embodiment of a regulator according to the present invention will be described in detail with reference to the drawings. Fig. 1 is a cross-sectional view of a regulator 1. The up and down direction in Fig. 1 corresponds to the opening and closing direction of a valve element 14, which will be described later. The drawings referred to are exaggerated for ease of understanding and do not accurately represent the shapes and dimensions of each component.

[0037] (Regulator configuration) The regulator 1 according to this embodiment is a pressure control device that controls the pressure of chemical liquid, pure water, or the like (hereinafter referred to as control fluid) used in a semiconductor manufacturing process (for example, a film formation process for a wafer).

[0038] As shown in Fig. 1, regulator 1 comprises valve body 11, upper cover 12, and lower cover 13. Upper cover 12 and lower cover 13 are assembled to valve body 11 so as to sandwich valve body 11 from the top and bottom in the figure (the same direction as the opening and closing direction of valve element 14, described below). Valve body 11 is a liquid-contacting member through which a control fluid flows, and is therefore molded from a highly corrosion-resistant fluorine-based synthetic resin. On the other hand, upper cover 12 and lower cover 13, which are not liquid-contacting members, are molded from, for example, polypropylene resin.

[0039] The valve body 11 is formed with an input port 111 into which the control fluid is input and an output port 112 from which the control fluid is output. A supply source (not shown) of the control fluid is connected to the input port 111, and the control fluid is input from the supply source to the regulator 1. For example, a nozzle (not shown) is connected to the output port 112, and the control fluid output from the regulator 1 is dropped onto a wafer or the like.

[0040] An upstream fluid chamber 113 is formed in the valve body 11 from the end face of the valve body 11 on the lower cover 13 side (the lower end face in FIG. 1 ) toward the upper cover 12 side. This upstream fluid chamber 113 is formed as a space having a substantially truncated cone shape. The upstream fluid chamber 113 is in communication with the input port 111 via an input flow path 111a. Furthermore, a valve hole 114 is formed in the inner surface 113a of the upstream fluid chamber 113 on the upper cover 12 side. This valve hole 114 is positioned coaxially with the upstream fluid chamber 113. An annular valve seat 115 is formed on the inner surface 113a of the upstream fluid chamber 113, protruding along the outer periphery of the valve hole 114. The tip of the annular valve seat 115 is flattened and forms the abutment surface with which the valve disc 14, described later, abuts.

[0041] Furthermore, an opening 116 is formed in the valve body 11 as a substantially cylindrical space extending from the end face of the valve body 11 on the upper cover 12 side (the upper end face in FIG. 1) toward the lower cover 13 side. This opening 116 is provided coaxially with the upstream fluid chamber 113 and the valve hole 114. The opening 116 is divided into two chambers in the opening / closing direction by a diaphragm member 15 (described later). That is, the opening 116 is divided into a downstream fluid chamber 116a and a pressure application chamber 116b. The downstream fluid chamber 116a is in communication with the upstream fluid chamber 113 via the valve hole 114. The downstream fluid chamber 116a is in communication with the output port 112 via an output flow path 112a. Therefore, in the valve body 11, a series of flow paths from the input port 111 to the output port 112 are formed by the input flow path 111a, the upstream fluid chamber 113, the valve hole 114, the downstream fluid chamber 116a, and the output flow path 112a.

[0042] A substantially cylindrical valve element 14 that can reciprocate in the opening and closing directions is housed in the upstream fluid chamber 113. This valve element 14 is a liquid-contacting member, and is therefore molded from a highly corrosion-resistant material such as a fluorine-based synthetic resin (PTFE or PFA).

[0043] The valve element 14 has an expanded diameter portion 141 formed in its axial center, which has a larger diameter than the other portions. The end face of the expanded diameter portion 141 facing the valve seat 115a is an abutment surface that abuts against the annular valve seat 115. Therefore, when the regulator 1 is in a valve-closed state, the valve element 14 and the annular valve seat 115 abut against each other at their flat surfaces. In this manner, when the abutment surface of the valve element 14 abuts against the annular valve seat 115, the flow path from the input port 111 to the output port 112 is blocked. On the other hand, when the abutment surface is separated from the valve seat 115a, the flow path from the input port 111 to the output port 112 is open.

[0044] Furthermore, the valve element 14 is provided with a thin film portion 142 molded integrally with the valve element 14 at the end on the lower cover 13 side, and a fixed portion 143 formed on the outer periphery of the thin film portion 142. The fixed portion 143 is sandwiched between the valve body 11 and the lower cover 13, thereby fixing the valve element 14 so that it is positioned coaxially with the upstream fluid chamber 113. The thin film portion 142 is formed so as to be elastically deformable as the valve element 14 reciprocates in the opening and closing directions.

[0045] The valve element 14 has a shaft portion 145 that protrudes from the expanded diameter portion 141 toward the upper cover 12. This shaft portion 145 extends through the valve hole 114 to the downstream fluid chamber 116a. The tip of the shaft portion 145 is loosely fitted into the diaphragm member 15 so as to be separable. This diaphragm member 15 is formed in a substantially disk shape. Furthermore, since the diaphragm member 15 is a liquid-contacting member, it is molded from a highly corrosion-resistant material, such as a fluorine-based synthetic resin.

[0046] The diaphragm member 15 is made up of a central portion 151, a thin film portion 152 formed on the outer periphery of the central portion 151, and an annular fixing portion 153 formed on the outer periphery of the thin film portion 152. A receiving portion 151a is drilled into the center of the end surface of the central portion 151 facing the valve disc 14. This receiving portion 151a is designed to be positioned coaxially with the shaft portion 145 of the valve disc 14, and the tip of the shaft portion 145 is loosely fitted into it. This loose fit is intended to position the central axis so that it does not move when the valve disc 14 moves in the closing direction (upward in the figure), and also to allow the diaphragm member 15 and the valve disc 14 to separate when a force acts in a direction that moves them apart.

[0047] The fixed portion 153 of the diaphragm member 15 is sandwiched between the upper cover 12 and the valve body 11, thereby fixing the diaphragm member 15. By being fixed in this manner, the central portion 151 is able to reciprocate in the opening and closing directions together with the valve element 14 while elastically deforming the thin film portion 152. An O-ring 19 is disposed between the fixed portion 153 and the upper cover 12, keeping the pressure application chamber 116b airtight.

[0048] An inlet port 121 communicating with the pressure application chamber 116b is formed in the upper cover 12, and operation air can be supplied to the pressure application chamber 116b through the inlet port 121. Then, the position of the central portion 151 of the diaphragm member 15 in the opening / closing direction varies depending on the pressure of the operation air supplied to the pressure application chamber 116b. When the central portion 151 moves in the opening direction (downward in FIG. 1), the movement of the central portion 151 pushes the valve element 14 down in the opening direction, resulting in an open valve state.

[0049] A spring accommodating chamber 131 is formed in the lower cover 13 as a substantially cylindrical space coaxial with the valve body 14. The spring accommodating chamber 131 is located on the opposite side of the upstream fluid chamber 113 across the thin film portion 142 of the valve body 14. A compression coil spring 16 is accommodated in the spring accommodating chamber 131.

[0050] Furthermore, a concave guide portion 132 is provided in the spring accommodating chamber 131 and is coaxial with the valve body 14. A support member 17 that supports the valve body 14 from the lower cover 13 side is inserted into the guide portion 132. A compression coil spring 16 abuts against a flange portion 171 that protrudes from the outer circumferential surface of the support member 17. This biases the support member 17 toward the valve body 11 side (upward in the figure).

[0051] The support member 17 supports the valve disc 14 by inserting the lower end of the valve disc 14 into a groove 172 formed in the upper end surface on the valve disc 14 side. The support member 17 is biased upward by the compression coil spring 16, and the valve disc 14 supported by the support member 17 is also biased upward. In other words, the valve disc 14 is biased in the closing direction toward contact with the annular valve seat 115. When the valve disc 14 moves in the opening direction, it moves against the biasing force of the compression coil spring 16. In other words, the position of the valve disc 14 is adjusted by balancing the pressure of the operating air supplied to the pressure application chamber 116b and the biasing force of the compression coil spring 16. Adjusting the position of the valve disc 14 means adjusting the distance between the valve disc 14 and the annular valve seat 115 (adjusting the opening degree).

[0052] Furthermore, the support member 17 is provided with a sliding portion 173 that is inserted into the guide portion 132 at the end (the lower end in the drawing) opposite the valve body 14. The movement of the valve body 14 toward and away from the annular valve seat 115 is guided by the guide portion 132 because the sliding portion 173 is inserted into the guide portion 132.

[0053] Next, the portion where the shaft portion 145 of the valve body 14 and the diaphragm member 15 are loosely fitted will be described in more detail with reference to Figures 2 and 3. Figure 2 is a partial enlarged view of portion A in Figure 1. Figure 3 is a partial enlarged view of portion B in Figure 2.

[0054] As already described, the diaphragm member 15 (central portion 151) is provided with a receiving portion 151a that receives the tip surface of the shaft portion 145 of the valve body 14. This receiving portion 151a is shaped like a stop hole, and is designed to abut against the tip surface of the shaft portion 145. The portion of the receiving portion 151a that abuts against the tip surface of the shaft portion 145 is formed as a concave spherical surface 151b. The center position CP11 of this concave spherical surface 151b is designed to be located on the central axis CL11 of the shaft portion 145. Furthermore, the radius SR11 (first radius) of the concave spherical surface 151b is preferably equal to or greater than the diameter D11 of the stem 145 minus 20% of the diameter D11, and is preferably equal to or less than the diameter D11 of the stem 145 plus 20% of the diameter D11. It is more preferably equal to or greater than the diameter D11 of the stem 145 minus 10% of the diameter D11, and is preferably equal to or less than the diameter D11 of the stem 145 plus 10% of the diameter D11. In this embodiment, the diameter D11 of the stem 145 is set to 4 mm, and the radius SR11 is set to the same value, 4 mm. Note that the values ​​given here are merely examples.

[0055] Furthermore, a cylindrical wall 151c facing the outer peripheral surface of the shaft portion 145 is formed on the outer periphery of the concave spherical surface 151b of the receiving portion 151a. The diameter D12 of the cylindrical wall 151c is set so that a gap C11 between the cylindrical wall 151c and the outer peripheral surface of the shaft portion 145 is a predetermined size. That is, the size of the gap C11 is set to 3-5% of the diameter D11 of the shaft portion 145. In this embodiment, since the diameter of the shaft portion 145 is set to 4 mm, it is desirable to set the gap C11 to 0.12-0.2 mm. Note that the gap C11 here is calculated by subtracting the diameter D11 of the shaft portion 145 from the diameter D12 of the cylindrical wall 151c, assuming that the shaft portion 145 and the cylindrical wall 151c are coaxial, and dividing the result by 2.

[0056] The tip surface of the shaft portion 14, which is loosely fitted into the receiving portion 151a as described above, facing the concave spherical surface 151b, is a convex spherical surface 144. The center position of this convex spherical surface 144 is designed to be the same as the center position CP11 of the concave spherical surface 151b when the convex spherical surface 144 and the concave spherical surface 151b are in contact with each other. Furthermore, the radius SR12 (second radius) of the convex spherical surface 144 is preferably the radius SR11 of the concave spherical surface 151b minus 2-5% of the radius SR11, and more preferably the radius SR11 minus 3-4% of the radius SR11. In this embodiment, the radius SR11 of the concave spherical surface 151b is set to 4 mm, and the radius SR12 of the convex spherical surface 144 is set to 3.85 mm. Note that the values ​​listed here are merely examples.

[0057] Furthermore, as shown in FIG. 3, a kneading hole 146 is drilled coaxially with the shaft portion 145 in the distal end surface of the shaft portion 145. By drilling the kneading hole 146, the apex of the convex spherical surface 144 becomes a non-contact portion 147 that does not contact the concave spherical surface 151b by an amount corresponding to the diameter D13 of the kneading hole 146. It is desirable that the diameter D13 of the kneading hole 146 (i.e., the diameter of the non-contact portion 147) does not exceed 1 / 20 of the diameter D11 of the shaft portion 145. In this embodiment, the diameter D11 of the shaft portion 145 is set to 4 mm, and the diameter D13 is set to 0.2 mm. Note that the numerical values ​​given here are merely examples. The size of the diameter D13 of the kneading hole 146 in FIG. 3 has been exaggerated for ease of explanation and does not represent the exact dimensions.

[0058] (Regulator action and effects) The regulator 1 can stabilize the pressure of the control fluid output from the output port 112 by adjusting the pressure of the operating air supplied to the pressure application chamber 116b.

[0059] Operating air at a given pressure is supplied to the regulator 1, creating a positive pressure in the pressure application chamber 116b, thereby opening the regulator 1. This causes the regulator 1 to output control fluid. In this case, for example, if the amount of control fluid used in the downstream nozzle of the regulator 1 increases, the pressure in the downstream fluid chamber 116a decreases. If the pressure in the downstream fluid chamber 116a becomes lower than the pressure of the operating air supplied to the pressure application chamber 116b, the thin film portion 152 of the diaphragm member 15 deforms toward the downstream fluid chamber 116a, and the diaphragm member 15 moves to a position where the pressure in the downstream fluid chamber 116a and the biasing force of the compression coil spring 16 are balanced with the pressure in the pressure application chamber 116b. This increases the aperture of the valve element 14. On the other hand, if the amount of control fluid used in the downstream nozzle of the regulator 1 decreases, the pressure in the downstream fluid chamber 116a increases. When the pressure in the downstream fluid chamber 116a becomes greater than the pressure of the operating air supplied to the pressure application chamber 116b, the thin film portion 152 of the diaphragm member 15 deforms toward the pressure application chamber 116b, and the diaphragm member 15 moves to a position where the pressure in the downstream fluid chamber 116a and the biasing force of the compression coil spring 16 are balanced with the pressure in the pressure application chamber 116b. As a result, the opening of the valve element 14 decreases.

[0060] In this way, the diaphragm member 15 changes its position in the opening / closing direction while elastically deforming the thin film portion 152 in accordance with the pressure balance between the pressure of the operating air supplied to the pressure application chamber 116b and the biasing force of the downstream fluid chamber 116a and the compression coil spring 16. This adjusts the position of the valve element 14 in the opening / closing direction, thereby stabilizing the pressure of the control fluid output from the output port 112. Note that when the supply of operating air to the pressure application chamber 116b is stopped, the biasing force of the compression coil spring 16 moves the valve element 14 to a position where it abuts against the annular valve seat 115, thereby blocking the flow of the control fluid.

[0061] Furthermore, since the shaft portion 145 of the valve element 14 is loosely fitted in the receiving portion 151a of the diaphragm member 15 so as to be separable, excessive interference between the valve element 14 and the annular valve seat 115 can be prevented.

[0062] More specifically, for example, when back pressure from the output port 112 side is applied and the pressure in the downstream fluid chamber 116a increases suddenly, the diaphragm member 15 is pushed upward in Fig. 1 (i.e., in the closing direction). If the valve element 14 and the diaphragm member 15 are connected so that they cannot be separated at this time, the valve element 14 may move in the closing direction as the diaphragm member 15 is pushed upward in the closing direction, causing excessive interference with the annular valve seat 115. Excessive interference between the valve element 14 and the annular valve seat 115 is undesirable because it can cause particle generation due to wear, etc.

[0063] However, in regulator 1 according to this embodiment, shaft portion 145 of valve element 14 is loosely fitted in receiving portion 151a of diaphragm member 15 so that even if the pressure in downstream fluid chamber 116a suddenly increases and diaphragm member 15 is pushed up in the closing direction, diaphragm member 15 separates from valve element 14 and moves independently in the closing direction. Therefore, valve element 14 is not moved in the closing direction, and excessive interference with annular valve seat 115 can be prevented.

[0064] If the shaft portion 145 of the valve element 14 is loosely fitted in the receiving portion 151a of the diaphragm member 15 so as to be separable, there is a risk that the tip surface of the shaft portion 145 and the receiving portion 151a will repeatedly come into contact with and separate from each other. However, the tip surface of the shaft portion 145 is provided with the convex spherical surface 144, and the receiving portion 151a is provided with the concave spherical surface 151b. This prevents excessive stress from being generated at the contact surface between the convex spherical surface 144 and the concave spherical surface 151b, and prevents slippage from occurring on the tip surface of the shaft portion 145. This prevents dust from being generated even if the tip surface of the shaft portion 145 and the receiving portion 151a repeatedly come into contact with and separate from each other.

[0065] First, we will explain the results of a finite element analysis performed on the stress generated on the contact surface (contact surface between convex spherical surface 144 and concave spherical surface 151b) between valve body 14 and diaphragm member 15. Fig. 4 is a diagram showing the results of a finite element analysis performed on the stress generated on the contact surface (contact surface between convex spherical surface 144 and concave spherical surface 151b) between valve body 14 and diaphragm member 15 in the first embodiment.

[0066] Furthermore, for comparison with the results of the above finite element analysis, finite element analysis was performed by changing the radius SR11 of concave spherical surface 151b and the radius SR12 of convex spherical surface 144.

[0067] For the first comparative example, a finite element method analysis was performed with the radius SR11 of the concave spherical surface 151b set to 3 mm and the radius SR12 of the convex spherical surface 144 set to 2.9 mm. Fig. 6 is a diagram showing the results of a finite element method analysis of the stress generated at the contact surface between the valve body 14 and the diaphragm member 15 for the first comparative example.

[0068] Furthermore, for a second comparative example, a finite element method analysis was performed with the radius SR11 of the concave spherical surface 151b set to 5 mm and the radius SR12 of the convex spherical surface 144 set to 4.82 mm. Fig. 8 shows the results of a finite element method analysis of the stress generated at the contact surface between the valve body 14 and the diaphragm member 15 for the second comparative example.

[0069] Furthermore, for a third comparative example, a finite element method analysis was performed with the radius SR11 of the concave spherical surface 151b set to 6 mm and the radius SR12 of the convex spherical surface 144 set to 5.80 mm. Fig. 10 is a diagram showing the results of a finite element method analysis of the stress generated at the contact surface between the valve body 14 and the diaphragm member 15 for the third comparative example.

[0070] Furthermore, as a fourth comparative example, a finite element method analysis was performed on the assumption that the valve body 14 and the diaphragm member 15 contact each other at their flat surfaces. Fig. 12 shows the results of a finite element method analysis of the stress generated at the contact surface between the valve body 14 and the diaphragm member 15 in the fourth comparative example.

[0071] These analyses assume that both the valve element 14 and the diaphragm member 15 are made of PTFE, and that the convex spherical surface 144 is pressed against the concave spherical surface 151b by the biasing force of the compression coil spring 16. The length and color density of the color bar represent the value of the generated stress. In other words, the longer the color bar, the greater the generated stress, and the darker the color bar, the greater the generated stress.

[0072] The results of the analysis will be described below. In this embodiment, as shown in Fig. 4, stress is high near the center axis CL11 and near the outer periphery of the convex spherical surface 144. Of these, the maximum stress occurs near the outer periphery of the convex spherical surface, and its value is 4.48 MPa.

[0073] In the first comparative example, the maximum stress occurs near the central axis CL11, and the stress decreases with increasing distance from the central axis CL11, as shown in Figure 6. The maximum stress value was 7.28 MPa.

[0074] 8, in the second comparative example, stress is high near the center axis CL11 and near the outer periphery of the convex spherical surface 144. Of these, the maximum stress occurs near the outer periphery of the convex spherical surface, and its value is 7.64 MPa.

[0075] 10, in the third comparative example, stress is high near the center axis CL11 and near the outer periphery of the convex spherical surface 144. Of these, the maximum stress occurs near the outer periphery of the convex spherical surface, and its value is 8.27 MPa.

[0076] 12, in the fourth comparative example, the stress increases with increasing distance from the central axis CL11, and the maximum stress occurs at the outer periphery of the convex spherical surface 144. The maximum stress value was 12.12 MPa.

[0077] Next, we will explain the results of a finite element analysis of the slippage of the tip surface of the stem 145 that occurs when the valve element 14 and the diaphragm member 15 come into contact (the convex spherical surface 144 comes into contact with the concave spherical surface 151b). Similar to the stress analysis described above, this analysis assumes that both the valve element 14 and the diaphragm member 15 are made of PTFE, and that the tip surface of the stem 145 is pressed against the receiving portion 151a of the diaphragm member 15 by the biasing force of the compression coil spring 16.

[0078] FIG. 5 shows the results of a finite element method analysis of slippage on the tip surface of the shank 145 in the first embodiment. Furthermore, similar finite element method analyses were performed on the first to fourth comparative examples. FIG. 7 shows the results of a finite element method analysis of slippage on the tip surface of the shank 145 in the first comparative example. FIG. 9 shows the results of a finite element method analysis of slippage on the tip surface of the shank 145 in the second comparative example. FIG. 11 shows the results of a finite element method analysis of slippage on the tip surface of the shank 145 in the third comparative example. FIG. 13 shows the results of a finite element method analysis of slippage on the tip surface of the shank 145 in the fourth comparative example. These analysis results represent the amount of slippage occurring depending on the length and color shade of the color bar. In other words, the longer the color bar, the greater the amount of slippage, and the darker the color bar, the greater the amount of slippage. Furthermore, the direction in which the color bar extends indicates the direction of slippage, with the portion of the color bar extending toward the shaft portion 145 indicating slippage toward the central axis CL11 (inward slippage), and the portion of the color bar extending toward the center portion 151 indicating slippage toward the opposite side of the central axis CL11 (outward slippage). Note that, hereinafter, inward slippage will be described as a positive value, and outward slippage will be described as a negative value, but the magnitude of the slippage will be determined by absolute value. That is, for example, when comparing a slippage of 0.3 μm with a slippage of −0.5 μm, −0.5 μm will be determined to be the larger slippage.

[0079] The results of the analysis will be explained below. In this embodiment, as shown in Fig. 5, outward slip, inward slip, outward slip, and inward slip are alternately distributed from the central axis CL11 side, and the amount of slip increases with increasing distance from the central axis CL11. The range of the amount of slip that occurs is -0.052 to 0.094 µm, and on average, inward slip occurs.

[0080] In the first comparative example, as shown in Figure 7, inward slippage occurs overall. The amount of slippage increases with increasing distance from the central axis CL11, reaching a maximum value nearer to the outer periphery than the midpoint between the central axis CL11 and the outer periphery. After passing this maximum value, the amount of slippage decreases toward the outer periphery. The range of the amount of slippage that occurs is 0 to 0.7 μm.

[0081] In the second comparative example, as shown in Fig. 9, outward slippage occurs overall. The amount of slippage increases with increasing distance from the central axis CL11, reaching a maximum value near the midpoint between the central axis CL11 and the outer periphery of the shaft portion 145. After passing this maximum value, the amount of slippage decreases toward the outer periphery. The range of the amount of slippage that occurs is -0.33 to 0 µm.

[0082] In the third comparative example, as shown in Figure 11, outward slippage occurs overall. The amount of slippage increases with increasing distance from the central axis CL11, reaching a maximum value nearer to the outer periphery than the midpoint between the central axis CL11 and the outer periphery. After passing this maximum value, the amount of slippage decreases toward the outer periphery. The range of the amount of slippage that occurs is -0.86 to 0 μm.

[0083] In the fourth comparative example, as shown in Fig. 13, outward slippage occurs overall. The amount of slippage increases with increasing distance from the central axis CL11, reaching a maximum value near the outer periphery. The range of the amount of slippage that occurs is -5.76 to 0 µm.

[0084] The results of the above analysis are summarized in the graphs shown in Figures 14 and 15. Figure 14 is a graph comparing maximum stress values ​​obtained by finite element method analysis. The vertical axis represents the maximum stress value, and the horizontal axis represents the radius SR11 of concave spherical surface 151b.

[0085] The value of 2 mm for the concave spherical surface SR indicates the analysis result for regulator 50 according to the prior art (see FIG. 28). The maximum stress value generated at the point of contact between tip surface 512 (convex spherical surface) of shaft portion 511 and receiving portion 571 (concave spherical surface) of diaphragm member 57 of regulator 50 is 10.92 MPa.

[0086] The concave spherical surface SR value of 3 mm represents the analysis result of the first comparative example. The maximum stress value was 7.28 MPa, which is about 67% of the value of regulator 50 according to the prior art.

[0087] The value of 4 mm for the concave spherical surface SR represents the analysis results of this embodiment. The maximum stress value is 4.48 MPa, which is less than half the value of the regulator 50 according to the prior art.

[0088] The concave spherical surface SR value of 5 mm represents the analysis results for the second comparative example. The maximum stress value was 7.64 MPa, which is about 70% of the value for regulator 50 according to the prior art.

[0089] The concave spherical surface SR value of 6 mm represents the analysis results for the third comparative example. The maximum stress value was 8.27 MPa, which is approximately 76% of the value for regulator 50 according to the prior art.

[0090] The value of ∞ for the concave spherical surface SR means that the surface is flat. This shows the analysis results for the fourth comparative example. The maximum stress value was 12.12 MPa, which is higher than that of regulator 50 according to the prior art.

[0091] 15 is a graph comparing the range of slippage amounts obtained by finite element analysis, where the vertical axis represents the slippage amount and the horizontal axis represents the value of the radius SR11 of the concave spherical surface 151b.

[0092] The value of 2 mm for the concave spherical surface SR indicates the analysis result for regulator 50 according to the prior art (see FIG. 28). The range of the amount of slippage occurring on the tip surface of shaft portion 511 is 0 to 2.9 μm, and inward slippage occurs.

[0093] The concave spherical surface SR value of 3 mm represents the analysis result of the first comparative example. The range of slippage occurring on the tip surface of shaft portion 145 is 0 to 0.7 μm, and inward slippage occurs. Furthermore, the magnitude of the slippage is approximately 24% of the conventional value when compared at its maximum value.

[0094] The value of 4 mm for the concave spherical surface SR represents the analysis results of this embodiment. The range of slippage occurring on the tip surface of the stem 145 is -0.052 to 0.094 μm, with inward slippage occurring on average. Furthermore, the magnitude of the slippage is approximately 3% of the conventional maximum value.

[0095] The concave spherical surface SR value of 5 mm represents the analysis results for the second comparative example. The range of slippage occurring on the tip surface of shaft portion 145 is -0.33 to 0 μm, with outward slippage occurring. Furthermore, the magnitude of the slippage is approximately 11% of the conventional value when compared at its maximum value.

[0096] The concave spherical surface SR value of 6 mm represents the analysis results for the third comparative example. The range of slippage occurring on the tip surface of shaft portion 145 is -0.86 to 0 μm, with outward slippage occurring. Furthermore, the magnitude of the slippage is approximately 30% of the conventional value when compared at its maximum value.

[0097] The value of ∞ for the concave spherical surface SR means that the surface is flat, and the analysis results for the fourth comparative example are shown. The range of slippage occurring on the tip surface of the shaft portion 145 is -5.76 to 0 μm, and outward slippage occurs. Furthermore, when comparing the maximum value of the slippage, the magnitude is greater than that of the conventional example.

[0098] Based on the above analysis results and considering that the compressive strength of PTFE, the material of which valve body 14 and diaphragm member 15 are made, is approximately 10 MPa, it is desirable that radius SR11 of concave spherical surface 151b be 3-5 mm in order to keep the maximum stress value below 10 MPa, and considering tolerances, it is desirable that radius SR11 be equal to or greater than the value obtained by subtracting 20% ​​of diameter D11 from the value of diameter D11 of stem portion 145 and equal to or less than the value obtained by adding 20% ​​of diameter D11 to the value of diameter D11 of stem portion 145. Note that when radius SR11 of concave spherical surface 151b is 6 mm, there is not much difference between when radius SR11 is 3 mm and when it is 5 mm, in terms of comparing only the maximum stress value, but the large amount of outward sliding that occurs on the tip surface of stem portion 145 is undesirable. This is because inward slippage has the effect of aligning the axis of the shaft portion 145, whereas outward slippage may cause the axis of the shaft portion 145 to become misaligned.

[0099] Furthermore, since the compressive strength of PTFE is thought to be approximately 5 MPa in a high-temperature atmosphere (for example, 90°C, which is the temperature of the control fluid), taking this into consideration, it is most desirable that the radius SR11 of the concave spherical surface 151b be 4 mm, which is the same as the value of the diameter D11 of the shaft portion 145, and taking tolerances into consideration, it is desirable that the radius SR11 be greater than or equal to the value of the diameter D11 of the shaft portion 145 minus 10% of the value of the diameter D11, and less than or equal to the value of the diameter D11 of the shaft portion 145 plus 10% of the value of the diameter D11.

[0100] The mechanism of the reduction in slippage is believed to be as follows. Figure 31 is a diagram illustrating the force acting on the valve element 14 and the diaphragm member 15 when they come into contact with each other in the first embodiment. Figure 32 is a diagram illustrating the force acting on the valve element 51 and the diaphragm member 57 when they come into contact with each other in the prior art. Note that in both Figures 31 and 32, the valve elements 14, 51 and the diaphragm members 15, 57 are shown separated from each other to make the explanation easier to understand.

[0101] The diaphragm member 57 and the valve body 51, which are in contact with each other, are subjected to a biasing force F31 of a compression coil spring 58 (see FIG. 28) and a reaction force F32 against the biasing force F31.

[0102] A compressive force F33 in the vertical direction acts on the diaphragm member 57 due to the biasing force F31 of the compression coil spring 58 and the reaction force F32 thereof. This compressive force F33 generates a force F34 in the diaphragm member 57 that tends to expand radially outward around the central axis CL51. Furthermore, a reaction force F35 is generated on the surface of the receiving portion 571 (at a location distance X from the central axis CL51) due to contact with the shaft portion 511, and this reaction force F35 is resolved to generate a tangential force F36. This force F36 becomes a force that tends to expand the receiving portion 571 radially outward around the central axis CL51.

[0103] Furthermore, a compressive force F37 acts in the vertical direction on the shaft portion 511 of the valve body 51 due to the biasing force F31 of the compression coil spring 58 and its reaction force F32. This compressive force F37 generates a force F38 in the shaft portion 511 that tends to expand radially outward around the central axis CL51. Furthermore, a contact force F39 is generated on the tip surface 512 of the shaft portion 511 (at a location a distance X from the central axis CL51) against the receiving portion 571, and this contact force F39 is resolved to generate a tangential force F40. This force F40 acts as a force that tends to contract the tip surface 512 of the shaft portion 511 radially inward around the central axis CL51.

[0104] A finite element analysis of the slippage of the tip surface of shaft portion 511 revealed that inward slippage occurred (see FIG. 30). This is thought to be because the amount of radially inward deformation of shaft portion 511 due to the force tending to contract radially inward is greater than the amount of radially outward deformation of receiving portion 571 and shaft portion 511 due to the force tending to expand radially outward.

[0105] Meanwhile, in regulator 1 according to the present embodiment, diaphragm member 15 and valve element 14, which are in contact with each other, are subjected to biasing force F11 of compression coil spring 16 (see FIG. 1) and reaction force F12 against biasing force F11.

[0106] A compressive force F13 in the vertical direction acts on the diaphragm member 15 due to the biasing force F11 of the compression coil spring 16 and the reaction force F12 thereof. This compressive force F13 generates a force F14 in the diaphragm member 15 that tends to expand radially outward around the central axis CL11. Furthermore, a reaction force F15 is generated by contact with the shaft portion 145 at the concave spherical surface 151b of the receiving portion 151a (at a location a distance X from the central axis CL11), and this reaction force F15 is resolved to generate a tangential force F16. This force F16 acts as a force that tends to expand the receiving portion 151a radially outward around the central axis CL11.

[0107] Furthermore, a compressive force F17 acts in the vertical direction on the shaft portion 145 of the valve body 14 due to the biasing force F11 of the compression coil spring 16 and the reaction force F12 thereof. This compressive force F17 generates a force F18 in the shaft portion 145 that tends to expand radially outward around the central axis CL11. Furthermore, a contact force F19 with the receiving portion 151a is generated at the convex spherical surface 144 (at a location a distance X from the central axis CL11), which is the tip surface of the shaft portion 145. This contact force F19 is resolved to generate a tangential force F20. This force F20 acts as a force that tends to contract the convex spherical surface 144 of the shaft portion 145 radially inward around the central axis CL11.

[0108] A finite element analysis of the slippage on the tip surface of shaft portion 145 showed that inward slippage occurs on average (see FIG. 5). This is thought to be because the amount of radially inward deformation of shaft portion 145 due to the force tending to contract radially inward is greater than the amount of radially outward deformation of receiving portion 151a and shaft portion 145 due to the force tending to expand radially outward.

[0109] However, the maximum amount of slippage is about 3% of the previous value, which is a significant reduction in the amount of slippage. This is because by setting the radius SR11 of the concave spherical surface 151b and the diameter D11 of the shaft portion 145 to be equal to or greater than the value obtained by subtracting 20% ​​of the value of the diameter D11 from the value of the diameter D11 of the shaft portion 145, and equal to or less than the value obtained by adding 20% ​​of the value of the diameter D11 to the value of the diameter D11 of the shaft portion 145, or equal to or greater than the value obtained by subtracting 10% of the value of the diameter D11 from the value of the diameter D11 of the shaft portion 145, and equal to or less than the value obtained by adding 10% of the value of the diameter D11 to the value of the diameter D11 of the shaft portion 145, the reaction force F15 generated on the concave spherical surface 151b is at an angle close to perpendicular to the concave spherical surface 151b, thereby reducing the force tending to expand radially outward, and the contact force F19 generated on the convex spherical surface 144 is at an angle close to perpendicular to the convex spherical surface 144, thereby reducing the force tending to contract radially inward. The reduction in radial force reduces the amount of radial deformation, which in turn reduces the amount of slippage.

[0110] As described above, the regulator 1 according to this embodiment has the following features: (1) An upstream fluid chamber 113 in which a valve element 14 is accommodated, a downstream fluid chamber 116a located downstream of the upstream fluid chamber 113, a valve hole 114 connecting the upstream fluid chamber 113 and the downstream fluid chamber 116a, an annular valve seat 115 provided along the outer periphery of the valve hole 114 and against which the valve element 14 comes into contact and separates, and a diaphragm member 15 accommodated in the downstream fluid chamber 116a and changing its position along the contact and separation direction in accordance with the pressure of the operating air, the valve element 14 having a cylindrical shaft portion 145 extending along the contact and separation direction from the upstream fluid chamber 113 through the valve hole 114 to the downstream fluid chamber 116a, the shaft portion 145 being loosely fitted in a receiving portion 151a of the diaphragm member 15 that receives the tip end surface of the shaft portion 145, and the valve element 14 is attached to the side of the valve element 14 opposite to the side of the diaphragm member 15. In regulator 1, a biasing means (e.g., compression coil spring 16) is provided that applies a biasing force to receiving portion 151a in a direction that brings it into contact with annular valve seat 115, and the opening of valve element 14 is adjusted by the balance between the pressure of the operating air and the biasing force, wherein receiving portion 151a has, at a portion facing the tip surface, concave spherical surface 151b formed by a first radius (radius SR11) whose center is located on central axis CL11 of stem portion 145, and first radius (radius SR11) is equal to or greater than the value obtained by subtracting 20% ​​of diameter D11 from the value of diameter D11 of stem portion 145, and the portion of the tip surface facing concave spherical surface 151b is convex spherical surface 144 formed by a second radius (radius SR12) whose value is the value obtained by subtracting 2-5% of the value of the first radius (radius SR11) from the value of diameter D11.

[0111] According to the regulator 1, the first radius (radius SR11) is equal to or greater than the value obtained by subtracting 20% ​​of the value of the diameter D11 from the value of the diameter D11 of the shaft portion 145, so that the stress generated on the contact surface when the valve body 14 and the diaphragm member 15 come into contact can be suppressed to 10 MPa or less. For example, highly corrosion-resistant materials such as PTFE and PFA are selected for the valve body 14 and diaphragm member 15, with the compressive strength of PTFE being approximately 10 MPa and that of PFA being approximately 15 MPa. Even if PTFE, which has a low compressive strength, is selected, as described above, the stress generated at the contact surface can be kept to 10 MPa or less, thereby preventing plastic deformation of the valve body 14 and diaphragm member 15, and therefore breakage and dust generation.

[0112] Furthermore, according to the regulator 1, the first radius (radius SR11) is equal to or greater than the value obtained by subtracting 20% ​​of the value of diameter D11 from the value of diameter D11 of shaft portion 145, so that the amount of slippage of shaft portion 145 at the contact surface between valve element 14 and diaphragm member 15 can be reduced to 30% or less of the conventional amount when compared at its maximum value. Reducing the amount of slippage of shaft portion 145 makes it possible to reduce dust generation.

[0113] As described above, if the stress and slippage occurring on the contact surface can be reduced, the risk of dust generation on the contact surface can be reduced, which in turn can prevent particles from being mixed into the control fluid and, ultimately, prevent a decrease in semiconductor manufacturing efficiency.

[0114] (2) In the regulator 1 described in (1), it is preferable that the first radius (radius SR11) be equal to or less than the sum of the diameter D11 of the shaft portion 145 and 20% of the diameter D11. This reliably suppresses the stress generated at the contact surface between the valve element 14 and the diaphragm member 15 to 10 MPa or less, thereby preventing plastic deformation of the valve element 14 and the diaphragm member 15, and consequently preventing breakage and dust generation.

[0115] (3) In the regulator 1 described in (2), it is preferable that the first radius (radius SR11) be equal to or greater than the value obtained by subtracting 10% of the diameter D11 from the value of the diameter D11 of the stem portion 145 and equal to or less than the value obtained by adding 10% of the diameter D11 to the value of the diameter D11 of the stem portion 145. This makes it possible to suppress the stress generated at the contact surface when the valve element 14 and the diaphragm member 15 come into contact with each other to 5 MPa or less. The compressive strength of PTFE is thought to be approximately 5 MPa in a high-temperature atmosphere (e.g., 90°C, the temperature of the control fluid). By suppressing the stress generated at the contact surface when the valve element 14 and the diaphragm member 15 come into contact with each other to 5 MPa or less, it is possible to prevent plastic deformation of the valve element 14 and the diaphragm member 15, and therefore damage and dust generation, even in a high-temperature atmosphere.

[0116] (4) In the regulator 1 described in any one of (1) to (3), the second radius (radius SR12) is preferably the first radius (radius SR11) minus 3-4% of the first radius (radius SR11). This reliably reduces stress generated at the contact surface between the valve element 14 and the diaphragm member 15. For example, if the second radius (radius SR12) is set to a value greater than the first radius (radius SR11) minus 2% of the first radius (radius SR11), the degree of freedom of the shaft portion 145 of the valve element 14 within the receiving portion 151a of the diaphragm member 15 is reduced. If the valve element 14 tilts during opening or closing, the tilt cannot be absorbed, and excessive stress may be generated at the contact surface. On the other hand, if the second radius (radius SR12) is set to a value smaller than the value obtained by subtracting 4% of the value of the first radius (radius SR11) from the value of the first radius (radius SR11), the shaft portion 145 of the valve body 14 may not sufficiently abut against the receiving portion 151a of the diaphragm member 15, and the central axis CL11 of the shaft portion 145 may become distorted. Therefore, as described above, it is preferable that the second radius (radius SR12) be a value obtained by subtracting 3-4% of the value of the first radius (radius SR11) from the value of the first radius.

[0117] (7) In the regulator 1 described in any one of (1) to (6), it is preferable that the receiving portion 151a has a cylindrical wall 151c facing the outer peripheral surface of the shaft portion 145, that there is a gap C11 between the cylindrical wall 151c and the outer peripheral surface of the shaft portion 145, and that the size of the gap C11 is 3-5% of the value of the diameter D11 of the shaft portion 145.

[0118] According to the regulator 1 described in (7), the receiving portion 151a has a cylindrical wall 151c facing the outer peripheral surface of the shaft portion 145, and therefore the cylindrical wall 151c can reliably prevent the central axis CL11 of the shaft portion 145 from shifting.

[0119] Furthermore, when the biasing force of the biasing means (compression coil spring 16) presses shaft portion 145 against receiving portion 151a, shaft portion 145 is compressed, which may cause deformation in a direction that increases the diameter of shaft portion 145. However, according to regulator 1 described in (7), because gap C11 is provided between cylindrical wall 151c and the outer peripheral surface of shaft portion 145, interference between cylindrical wall 151c and shaft portion 145 can be prevented even when the diameter of shaft portion 145 is compressed and increases. Preventing interference can prevent friction between shaft portion 145 and cylindrical wall 151c, which could cause dust generation. Here, the size of gap C11 is preferably 3-5% of the diameter D11 of shaft portion 145. If the size of gap C11 is larger than 5% of diameter D11 of shaft portion 145, it will be impossible to reliably prevent wobble of central axis CL11 of shaft portion 145, and if it is smaller than 3% of diameter D11 of shaft portion 145, there is a risk of interference with cylindrical wall 151c when shaft portion 145 is compressed and thickened. Note that the gap C11 referred to here is calculated by subtracting diameter D11 of shaft portion 145 from diameter D12 of cylindrical wall 151c and dividing the value by 2, assuming that shaft portion 145 and cylindrical wall 151c are positioned coaxially.

[0120] (8) In the regulator 1 described in any one of (1) to (7), a non-contact portion 147 that does not contact the concave spherical surface 151b is provided at the apex of the convex spherical surface 144, coaxially with the shaft portion 145, and the diameter D13 of the non-contact portion 147 does not exceed 1 / 20 of the value of the diameter D11 of the shaft portion 145.

[0121] Convex spherical surface 144 is expected to be formed by cutting, injection molding, or the like. When formed by cutting, the machining speed at the apex of convex spherical surface 144 is zero, potentially resulting in burrs. Contacting concave spherical surface 151b with burrs may result in dust generation. Therefore, as in regulator 1 described in (7), dust generation can be prevented by providing non-contact portion 147 at the apex of convex spherical surface 144. Furthermore, if convex spherical surface 144 is formed by injection molding, a gate located on the surface of convex spherical surface 144 may not fully achieve the effect of reducing stress and slippage that occurs at the contact surface when valve element 14 and diaphragm member 15 come into contact. Therefore, as in regulator 1 described in (7), providing non-contact portion 147 at the apex of convex spherical surface 144 allows the gate to be located at non-contact portion 147, which does not affect the above effect. However, it is desirable that the diameter D13 of the non-contact portion 147 does not exceed 1 / 20 of the diameter D11 of the shaft portion 145. If the diameter D13 of the non-contact portion 147 exceeds 1 / 20 of the diameter D11 of the shaft portion 145, the surface area of ​​the convex spherical surface 144 will be reduced accordingly, and the effect of suppressing the stress and the amount of slippage described above will not be sufficiently obtained.

[0122] (Second embodiment) Next, a regulator according to a second embodiment will be described, focusing only on the differences from the regulator according to the first embodiment, with reference to Fig. 16. Fig. 16 is an enlarged view of the contact portion between valve element 24 and diaphragm member 25 in the second embodiment, and corresponds to Fig. 2.

[0123] The regulator according to the second embodiment differs from the regulator according to the first embodiment only in the shapes of the receiving portion and the tip surface of the shaft. As shown in Fig. 16, receiving portion 251a of diaphragm member 25 has concave spherical surface 251b and concave curved surface 251c provided on the outer periphery of concave spherical surface 251b.

[0124] The concave spherical surface 251b is provided within a range indicated by an angle A11 centered on a central position CP21 on the central axis CL21 of the stem portion 245 of the valve body 24. The angle A11 is preferably within a range of 24 degrees ± 1 degree centered on the central position CP21. The radius SR21 (first radius) of the concave spherical surface 151b is preferably equal to or greater than the diameter D21 of the stem portion 245 minus 20% of the diameter D21. The upper limit of the radius SR21 is determined by the angle A11 and the radius SR22 of the concave curved surface 251c, which is tangentially connected to the concave spherical surface 151b. In this embodiment, the diameter D21 of the stem portion 145 is set to 4 mm, and the radius SR21 is set to 6 mm. Note that the values ​​given here are merely examples. The range of the concave spherical surface 251b is within the range indicated by the angle A11.

[0125] The concave curved surface 251c is tangent to the concave spherical surface 251b, and its radius R22 is set to be smaller than the radius SR21 of the concave spherical surface 251b. Specifically, it is desirable that the radius R22 be set to a value obtained by subtracting 60-65% of the value of the radius SR21 from the value of the radius SR21. In this embodiment, the radius R22 is set to 2.2 mm. Note that the values ​​given here are merely examples.

[0126] The tip surface of the shaft portion 245 of the valve body 24, which is loosely fitted into the receiving portion 251a as described above, is formed by a convex spherical surface 244 provided in a portion facing the concave spherical surface 251b, and a convex curved surface 246 provided on the outer periphery of the convex spherical surface 244 and in a portion facing the concave curved surface 251c.

[0127] The center position of this convex spherical surface 244 is designed to be the same as the center position CP21 of the concave spherical surface 251b when the convex spherical surface 244 and the concave spherical surface 251b are in contact with each other. Furthermore, the radius SR23 (second radius) of the convex spherical surface 244 is preferably the radius SR21 of the concave spherical surface 251b minus 2-5% of the radius SR21, and more preferably the radius SR21 minus 3-4% of the radius SR21. In this embodiment, the radius SR21 of the concave spherical surface 251b is set to 6 mm, and the radius SR23 of the convex spherical surface 244 is set to 5.6 mm. Note that the values ​​listed here are merely examples.

[0128] Convex curved surface 246 is tangentially continuous with convex spherical surface 244, and its radius R24 is set to be smaller than radius SR23 of convex spherical surface 244. Specifically, it is desirable that gap C21 (see FIG. 17) between the outer circumferential edge of convex curved surface 246 and concave curved surface 251c be 0.02 or more and 0.03 or less in the initial state. In this embodiment, radius R24 is set to 2.05 mm. Note that the values ​​given here are merely examples.

[0129] A regulator configured as described above was analyzed using the finite element method, as with regulator 1 according to the first embodiment. Fig. 18 shows the results of a finite element method analysis of the stress generated at the contact surface between valve element 24 and diaphragm member 25 in the second embodiment. Fig. 19 shows the results of a finite element method analysis of the slippage of the tip surface of shaft portion 245 in the second embodiment.

[0130] First, the results of the stress analysis will be described. As shown in Figure 18, the maximum stress occurs near the central axis CL21, and the stress decreases with increasing distance from the central axis CL21. The stress reaches its lowest value near the point where the convex curved surface 246 and the convex spherical surface 244 are tangent to each other, and the stress value increases from that point toward the outer periphery. The maximum stress value was 6.15 MPa.

[0131] Next, the analysis results of the amount of slippage will be explained. As shown in Fig. 19, outward slippage occurs on the side of the central axis CL21, and inward slippage occurs on the outer periphery of the shaft portion 245. The amount of slippage that occurs ranges from -0.235 to 0.122 µm, and on average, it is a slight outward slippage.

[0132] The results of the above analysis are compared with those of regulator 50 according to the prior art and regulator 1 according to the first embodiment. Fig. 26 is a graph comparing the maximum stress values ​​obtained by finite element method analysis for each configuration. Fig. 27 is a graph comparing the range of slippage obtained by finite element method analysis for each configuration.

[0133] As shown in Fig. 26, the maximum stress value in the second embodiment is 6.15 MPa, which is about 56% of the value in regulator 50 according to the prior art. Furthermore, as shown in Fig. 27, the range of slippage that occurs on the tip surface of shaft portion 245 in the second embodiment is -0.235 to 0.122 µm, and the magnitude of the slippage is about 8% of the conventional value when compared at the maximum value. The above results show that both the stress value and the slippage are slightly higher than in regulator 1 according to the first embodiment, but the reduction in stress value and the reduction in slippage are significantly reduced compared to regulator 50 according to the prior art, which means that this is effective in preventing dust generation.

[0134] (Third embodiment) Next, a regulator according to a third embodiment will be described, focusing only on the differences from the regulator according to the first embodiment, with reference to Fig. 20. Fig. 20 is an enlarged view of the contact portion between valve element 34 and diaphragm member 35 in the third embodiment, and corresponds to Fig. 2.

[0135] The regulator according to the third embodiment differs from the regulator according to the first embodiment only in the shapes of the receiving portion and the tip surface of the shaft. As shown in Fig. 20, receiving portion 351a of diaphragm member 35 has concave spherical surface 351b and first flat surface 351c provided on the outer periphery of concave spherical surface 351b.

[0136] The center position CP31 of the concave spherical surface 351b is designed to be located on the center axis CL31 of the stem portion 345 of the valve body 34. The radius SR31 (first radius) of the concave spherical surface 351b is preferably equal to or greater than the diameter D31 of the stem portion 345 minus 20% of the diameter D31, and is preferably equal to or less than the diameter D31 of the stem portion 345 plus 20% of the diameter D31. The radius SR31 is more preferably equal to or greater than the diameter D31 of the stem portion 345 minus 10% of the diameter D31, and is preferably equal to or less than the diameter D31 of the stem portion 345 plus 10% of the diameter D31. In this embodiment, the diameter D31 of the stem portion 345 is set to 4 mm, and the radius SR31 is also set to 4 mm. Note that the values ​​listed here are merely examples. The range of the concave spherical surface 351b is the range indicated by angle A21. The angle A21 is preferably 40 degrees±1 degree with the center position CP31 as the center.

[0137] The first flat surface 351c is provided on a tangent to the concave spherical surface 351b, and forms an angle A31 of 70 degrees with respect to the central axis CL31 of the shaft portion 345. Note that this angle A31 is set appropriately so that the size of the radius SR31 falls within the above-mentioned range.

[0138] The tip surface of the shaft portion 345 of the valve body 34, which is loosely fitted into the receiving portion 351a as described above, is formed by a convex spherical surface 344 provided in a portion facing the concave spherical surface 351b, and a second flat surface 346 provided on the outer periphery of the convex spherical surface 344 and in a portion facing the first flat surface 351c.

[0139] The center position of this convex spherical surface 344 is designed to be the same as the center position CP31 of the concave spherical surface 351b when the convex spherical surface 344 and the concave spherical surface 351b are in contact with each other. Furthermore, the radius SR33 (second radius) of the convex spherical surface 344 is preferably the radius SR31 of the concave spherical surface 351b minus 2-5% of the radius SR31, and more preferably the radius SR31 minus 3-4% of the radius SR31. In this embodiment, the radius SR31 of the concave spherical surface 351b is set to 4 mm, and the radius SR33 of the convex spherical surface 344 is set to 3.85 mm. Note that the values ​​listed here are merely examples.

[0140] The second flat surface 346 is provided on a tangent to the convex spherical surface 344, and forms an angle A32 of 69.25 degrees with respect to the central axis CL31 of the shaft portion 345. Note that the angle A32 is appropriately set so as to be smaller than the angle A31 and so that the size of the radius SR33 falls within the above-mentioned range.

[0141] A regulator configured as described above was analyzed using the finite element method, as with regulator 1 according to the first embodiment. Fig. 21 shows the results of a finite element method analysis of the stress generated at the contact surface between valve element 34 and diaphragm member 35 in the third embodiment. Fig. 22 shows the results of a finite element method analysis of the slippage of the tip surface of shaft portion 345 in the third embodiment.

[0142] First, the results of the stress analysis will be described. As shown in Fig. 21, stress is high near the center axis CL31 and near the outer periphery of shaft portion 345. Of these, the maximum stress occurred near the outer periphery of shaft portion 345, and its value was 6.82 MPa.

[0143] Next, the analysis results of the amount of slip will be explained. As shown in Fig. 22, outward slip occurs overall, and the amount of slip increases with increasing distance from the central axis CL31. The range of the amount of slip that occurs is -0.311 to 0.045 µm.

[0144] The results of the above analysis will be compared with the analysis results of the regulator 50 according to the prior art and the regulator 1 according to the first embodiment.

[0145] As shown in Fig. 26, the maximum stress value in the third embodiment is 6.82 MPa, which is about 63% of the value in regulator 50 according to the prior art. Furthermore, as shown in Fig. 27, the range of slippage that occurs on the tip surface of shaft 345 in the second embodiment is -0.311 to 0.045 µm, and the magnitude of the slippage is about 11% of the conventional value when compared at the maximum value. The above results show that both the stress value and the slippage are slightly higher than in regulator 1 according to the first embodiment, but the reduction in the stress value and the reduction in the slippage are significantly reduced compared to regulator 50 according to the prior art, which means that this is effective in preventing dust generation.

[0146] (Fourth embodiment) Next, a regulator according to a fourth embodiment will be described, focusing only on the differences from the regulator according to the first embodiment, with reference to Fig. 23. Fig. 23 is an enlarged view of the contact portion between valve element 44 and diaphragm member 45 in the third embodiment, and corresponds to Fig. 2.

[0147] In the regulator 1 according to the first embodiment, the receiving portion 151a includes a cylindrical wall 151c facing the outer peripheral surface of the shaft portion 145, thereby reliably preventing the shaft portion 145 from becoming misaligned. However, the cylindrical wall 151c is not necessarily provided. For example, as shown in FIG. 23 , the cylindrical wall 151c may be omitted, and instead, the convex spherical surface 444 on the distal end surface of the shaft portion 445 of the valve body 44 may be abutted against the concave spherical surface 451b of the receiving portion 451a of the diaphragm member 45. In this case, the distal end of the shaft portion 445 includes a thick-diameter portion 446 having a larger diameter than the remaining portion. By providing the thick-diameter portion 446, the width W11 of the convex spherical surface 444 is larger than the width W12 of the concave spherical surface 451b, thereby absorbing misalignment of the shaft portion. The radius SR42 of the convex spherical surface 444 and the radius SR41 of the concave spherical surface 451b are the same as in the first embodiment.

[0148] A regulator configured as described above was analyzed using the finite element method, as with regulator 1 according to the first embodiment. Fig. 24 shows the results of a finite element method analysis of the stress generated at the contact surface between valve element 44 and diaphragm member 45 in the fourth embodiment. Fig. 25 shows the results of a finite element method analysis of the slippage of the tip surface of shaft portion 445 in the fourth embodiment.

[0149] First, the results of the stress analysis will be described. As shown in Fig. 24, the maximum stress occurs near the central axis CL31, and the stress decreases with increasing distance from the central axis CL41. Furthermore, an increase in stress is observed at the outermost periphery where the convex spherical surface 444 and the concave spherical surface 451b are in contact. The maximum stress value was 4.47 MPa.

[0150] Next, the analysis results of the amount of slip will be described. As shown in Fig. 25, inward slip occurs near the center axis CL41, and the amount of outward slip increases on the outer periphery side of the concave spherical surface 451b. The range of the amount of slip that occurs is -0.160 to 0.128 µm.

[0151] The results of the above analysis will be compared with the analysis results of the regulator 50 according to the prior art and the regulator 1 according to the first embodiment.

[0152] As shown in Fig. 26, the maximum stress value in the fourth embodiment is 4.47 MPa, which is about 41% of that in regulator 50 according to the prior art. Also, as shown in Fig. 27, the range of slippage that occurs on the tip surface of shaft portion 445 in the second embodiment is -0.160 to 0.128 µm, and the magnitude of the slippage is about 5% of that of the prior art when compared at maximum values. The above results show that both the stress value and the slippage are equivalent to those of regulator 1 according to the first embodiment, and it can be said that this is effective in preventing dust generation.

[0153] The above-described embodiment is merely illustrative and does not limit the present invention in any way. Therefore, the present invention can naturally be improved and modified in various ways without departing from the spirit and scope of the present invention. For example, the non-contact portion 147 on the tip surface of the shaft portion 145 is formed by the kneading hole 146, but the apex of the convex spherical surface 144 may be made flat to provide the non-contact portion 147. Furthermore, in the above-described embodiment, the material of the valve body 14 and the diaphragm member 15 is described as PTFE, but this is not a limitation. Other fluorine-based synthetic resins (e.g., PFA) can also be used to similarly suppress dust generation. [Explanation of symbols]

[0154] 1 regulator 14 Valve body 15 Diaphragm member 16 Compression coil spring (an example of a biasing means) 113 Upstream fluid chamber 114 Valve orifice 115 Annular valve seat 116a Downstream fluid chamber 144 Convex spherical surface 145 Shaft 151a Receiving part 151b Concave spherical surface

Claims

1. an upstream fluid chamber in which a valve body is accommodated; a downstream fluid chamber located downstream of the upstream fluid chamber; a valve hole that connects the upstream fluid chamber and the downstream fluid chamber; an annular valve seat provided along an outer periphery of the valve hole, against which the valve body abuts and moves away; a diaphragm member accommodated in the downstream fluid chamber and adapted to change its position along a contact / separation direction in response to the pressure of the operating air; Equipped with the valve body includes a cylindrical shaft portion extending from the upstream fluid chamber through the valve hole to the downstream fluid chamber along the contact / separation direction, the shaft portion is separably fitted loosely into a receiving portion of the diaphragm member that receives a tip end surface of the shaft portion, a biasing means for applying a biasing force to the valve body in a direction in which the valve body abuts against the annular valve seat, on a side of the valve body opposite to the diaphragm member side; A regulator that adjusts the opening of the valve element by balancing the pressure of the operating air and the biasing force, the receiving portion has a concave spherical surface formed by a first radius and having a center located on the central axis of the shaft portion, at a portion facing the tip surface; the first radius is equal to or greater than the value obtained by subtracting 20% ​​of the diameter of the shaft portion from the value of the diameter, and the portion of the tip surface facing the concave spherical surface is a convex spherical surface formed by a second radius which is the value obtained by subtracting 2-5% of the first radius from the value of the first radius, thereby suppressing slippage of the convex spherical surface at the contact surface between the concave spherical surface and the convex spherical surface; A regulator comprising:

2. 2. The regulator of claim 1, the first radius is equal to or less than the value of the diameter of the shaft portion plus 20% of the value of the diameter; A regulator comprising:

3. 3. The regulator of claim 2, the first radius is equal to or greater than the value of the diameter of the stem portion minus 10% of the value of the diameter, and is equal to or less than the value of the diameter of the stem portion plus 10% of the value of the diameter; A regulator comprising:

4. 4. The regulator according to claim 1, the second radius is the value of the first radius minus 3-4% of the value of the first radius; A regulator comprising:

5. 2. The regulator of claim 1, the receiving portion has a concave curved surface formed on an outer periphery of the concave spherical surface with a radius smaller than the first radius and tangent to the concave spherical surface; the tip surface has a convex curved surface that is tangent to the convex spherical surface and has a radius smaller than the second radius, at an outer periphery of the convex spherical surface and at a portion facing the concave curved surface; A regulator comprising:

6. 2. The regulator of claim 1, the receiving portion has a first flat surface on an outer periphery of the concave spherical surface and on a tangent to the concave spherical surface; the tip end surface is provided with a second flat surface on a tangent to the convex spherical surface at a portion facing the first flat surface and on the outer periphery of the convex spherical surface; A regulator comprising:

7. 2. The regulator of claim 1, the receiving portion has a cylindrical wall facing the outer circumferential surface of the shaft portion; a gap is provided between the cylindrical wall and the outer circumferential surface of the shaft portion; The size of the gap is 3-5% of the diameter of the shaft portion; A regulator comprising:

8. 2. The regulator of claim 1, a non-contact portion that does not contact the concave spherical surface is provided at the apex of the convex spherical surface, coaxially with the shaft portion; the diameter of the non-contact portion does not exceed 1 / 20 of the diameter of the shaft portion; A regulator comprising:

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