Diaphragm valve

Abstract

The present invention provides a diaphragm valve capable of improving the aligning performance of a diaphragm, maintaining the sealing performance of a valve seat, and further improving the sealing performance of the valve seat, even when the thrust force for sealing the valve seat is suppressed to be small, in a freely detachable / mountable configuration having an assembly tolerance. A diaphragm valve (1) is provided with a diaphragm member (70) disposed so as to be in contact with the tip of a rod (50), a diaphragm (60) is brought into a valve-closed state in which the diaphragm (60) is in contact with a valve seat (44) via the diaphragm member (70) pressed by the rod (50) in the valve-closing direction, the tip surface (53a) of the rod (50) has a spherical shape, and the diaphragm member (70) is provided with a recess (71) in which the tip of the rod (50) is inserted and mounted. The inner bottom surface (71a) of the recess (71) has a spherical shape having a radius of curvature larger than the radius of curvature of the distal end surface (53a) of the rod (50) and having the central portion as the lowest surface.

Description

TECHNICAL FIELD

[0001] The present application relates to a diaphragm valve, and relates to a diaphragm valve in which a valve is opened and closed by a diaphragm by movement of a rod. BACKGROUND

[0002] Conventionally, a valve used for a semiconductor manufacturing apparatus or a solar cell manufacturing apparatus, a liquid crystal manufacturing apparatus, or the like is required to have a small dead zone and to suppress generation of particles, and as a valve that addresses this requirement, a diaphragm valve is used.

[0003] A diaphragm valve is subject to wear due to repeated contact and separation of a diaphragm and a valve seat, and thus requires periodic replacement of the diaphragm or the valve seat or the like. In particular, for example, in the case of a process in which a valve is caused to perform an opening and closing operation at a high temperature and at a high speed, such as an ALD (Atomic Layer Deposition) process, the valve seat or the like is further easily worn, and the valve seat or the like must be frequently replaced. Thus, a diaphragm valve in which parts are consumed in large amounts particularly requires high durability, and in order to achieve high durability, it is necessary to reduce a pushing force that seals the valve seat and suppress damage to the valve seat. In addition, on the other hand, in order to easily perform replacement of parts at the time of maintenance, it is necessary to improve disassembly / assembly. For example, in Patent Literature 1, a diaphragm valve in which disassembly / assembly is improved is described.

[0004] In this Patent Literature 1, a diaphragm valve having a diaphragm, a valve seat, or an assembly or a cartridge that facilitates replacement of the two is proposed. The diaphragm valve described in this Patent Literature 1 causes the diaphragm to abut against the valve seat via a button (diaphragm member) provided on the tip side of the rod of an actuator at the time of closing the valve. PRIOR ART DOCUMENT PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Laid-Open No. 2016-505125 SUMMARY PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] However, if the pushing force that seals the valve seat is reduced in the diaphragm valve described in Patent Literature 1, for example, due to the influence of a gap as a play of the rod and the diaphragm member inside the valve, the rod wobbles, the pushing manner of the rod against the diaphragm member becomes uneven, and the diaphragm valve is easily affected by tilting of the valve seat or the like caused by unevenness in parallelism of the valve seat or the valve body due to assembly tolerance, and there is a problem in that the sealing performance becomes unstable. In order to eliminate this problem, it is necessary to stabilize movement of the diaphragm member in the axial direction, and to improve the alignment performance of the diaphragm member.

[0007] The present application has been developed in order to solve the conventional problems, and has an object to provide a diaphragm valve in which, in a configuration that is freely assembled / disassembled with assembly tolerance, even if the thrust for sealing the valve seat is suppressed to be small, the alignment performance of the diaphragm member can be improved, the sealing performance of the valve seat is maintained, and further improvement of the sealing performance of the valve seat is sought. Means for solving the problems

[0008] In order to achieve the above object, the invention according to claim 1 is a diaphragm valve having a diaphragm member that is freely arranged in abutment with the tip end of a stem, and in which the diaphragm is brought to a closed state in which the diaphragm is in abutment with a valve seat via the diaphragm member that is pushed in the closing direction by the stem, the tip end surface of the stem is in a spherical shape, and in the diaphragm member, a recess into which the tip end portion of the stem is fitted is provided, and the inner bottom surface of the recess is in a spherical shape in which the curvature radius is larger than that of the tip end surface of the stem and in which the central portion is the lowest surface.

[0009] The invention according to claim 2 is a diaphragm valve in which the inner bottom surface of the recess is formed at a position that is deeper within a range in which a predetermined strength can be ensured.

[0010] The invention according to claim 3 is a diaphragm valve having a holding member that holds the diaphragm member so as to be freely movable in the axial direction of the diaphragm member, and in which the diaphragm member has a height in the axial direction that is guided by the holding member using the side surface of the diaphragm member as a sliding surface. Effects of the invention

[0011] According to the invention according to claim 1, the tip end surface of the stem is in a spherical shape, and in the diaphragm member, a recess into which the tip end portion of the stem is fitted is provided, and the inner bottom surface of the recess is in a spherical shape in which the curvature radius is larger than that of the tip end surface of the stem and in which the central portion is the lowest surface. Thus, in order to close the valve, when the tip end surface of the stem presses the inner bottom surface of the recess of the diaphragm member, the stem brings the spherical tip end surface into abutment with the spherical inner bottom surface of the recess and simultaneously moves toward the lowest surface of the inner bottom surface. Therefore, when the position at which the stem presses the diaphragm member becomes a position that is closer to the valve seat, the stem tilts and presses the inner bottom surface of the diaphragm member that is separate from the stem, the torque that rotates the diaphragm member is suppressed to be small, and the diaphragm member is prevented from tilting greatly due to the play of the assembly tolerance and a decrease in the alignment performance. Therefore, in a configuration that is freely assembled / disassembled with assembly tolerance, even if the thrust for sealing the valve seat is suppressed to be small, the alignment performance of the diaphragm member can be improved, the sealing performance of the valve seat is maintained, and further improvement of the sealing performance of the valve seat is sought.

[0012] According to the invention according to claim 2, the inner bottom surface of the recess of the diaphragm member is formed at a position deeper within the limit in which a predetermined strength can be ensured, so that the tip end surface of the rod is pressed against the inner bottom surface at a position deeper in the recess, and the rod presses the inner bottom surface at a position closer to the valve seat, whereby the moment acting on the diaphragm member when the rod is tilted to press the inner bottom surface of the recess can be suppressed to be smaller while ensuring the strength of the diaphragm member. Further, the tip end of the rod can be fitted into a position deeper in the recess of the diaphragm member, and as a result, the device size in the axial direction of the rod can be made compact. Furthermore, even in the case where the valve seat is tilted due to assembly tolerance, the position at which the rod presses the inner bottom surface can be made to be in the vicinity of the axis of the diaphragm member, and thus the alignment performance can be further improved.

[0013] According to the invention according to claim 3, there is provided a holding member that holds the diaphragm member so as to be movable in the axial direction of the diaphragm member, and the diaphragm member has a height that can be guided in the axial direction by the holding member with the side surface of the diaphragm member as a sliding surface. Thus, by stably ensuring the height of the diaphragm member and the sliding surface of the holding member for guiding in the axial direction of the diaphragm member, and at the same time, fitting the tip end of the rod into a position deeper in the recess of the diaphragm member, the position at which the rod presses the diaphragm member becomes a position closer to the valve seat. Therefore, the diaphragm member can be stably guided in the axial direction while suppressing the moment acting on the diaphragm member to be small. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a cross-sectional view showing the outline configuration of the open valve state of the diaphragm valve according to the embodiment. Figure 2 is a cross-sectional view showing the outline configuration of the closed valve state of the diaphragm valve according to the embodiment. Figure 3 is Figure 1 is a perspective cross-sectional view of the vicinity of the diaphragm. Figure 4 is an enlarged view of a portion of A shown in Figure 3 Figure 5 is an enlarged view of a portion of B shown in Figure 3 Figure 6 is a front view of the rod. Figure 7 is a front cross-sectional view of the diaphragm member. Figure 8A is a view for explaining the moment acting on the diaphragm member when the diaphragm member is pressed in a state where the rod is tilted. Figure 8B ​​This is a diagram for explaining the moment acting on the diaphragm when the diaphragm is pressed with the rod tilted. Figure 9 This figure explains the difference in centering performance caused by the difference in the depth of the inner bottom surface of the recessed portion when the diaphragm tilts in accordance with the valve seat that is slightly tilted due to assembly tolerance. Figure 10A This figure explains the difference in centering performance caused by the difference in the depth of the inner bottom surface of the recessed portion when the diaphragm tilts in accordance with the valve seat that is slightly tilted due to assembly tolerance. Figure 10B This figure explains the difference in centering performance caused by the difference in the depth of the inner bottom surface of the recessed portion when the diaphragm tilts in accordance with the valve seat that is slightly tilted due to assembly tolerance. DETAILED DESCRIPTION

[0015] In the following, based on Figure 1 to Figure 1 0 and describe in detail an embodiment of the diaphragm valve 1 involved in the present invention. The present disclosure is not limited to the embodiments shown below. It should be noted that the accompanying drawings are schematic diagrams, and the dimensional relationships and ratios of the elements may differ from reality. Furthermore, the accompanying drawings may also include portions where the dimensional relationships or ratios differ from each other. Figure 1 It is a cross-sectional view schematically showing the structure of the diaphragm valve 1 according to the embodiment in an open valve state. Figure 2 It is a cross-sectional view schematically showing the configuration of the diaphragm valve 1 according to the embodiment in a valve closed state. Figure 3 yes Figure 1 A perspective cross-sectional view of the vicinity of the diaphragm 60 is shown. Figure 4 Yes Figure 3 The portion A is shown in an enlarged view. Figure 5 Yes Figure 3 The portion shown in B is enlarged. Figure 6 It is a front view of the rod 50. Figure 7 4 is a front cross-sectional view of the diaphragm member 70 . Figure 8A and Figure 8B This is a diagram for explaining the moment acting on the diaphragm 70 when the diaphragm 70 is pressed with the rod 50 tilted. Figure 9 、 Figure 10A as well as Figure 10B This figure explains the difference in alignment performance caused by the difference in depth of the inner bottom surface 71 a of the recessed portion 71 when the diaphragm 70 is tilted according to the valve seat 44 which is slightly tilted due to assembly tolerance. Furthermore, in the description, the upward and downward directions are determined based on the drawing, but the directions are an example and not limited directions.

[0016] The diaphragm valve 1 according to an embodiment of the present application has an actuator 10, a valve body 30, and a coupling member 90 that couples the actuator 10 and the valve body 30. <About the actuator 10> The actuator 10 functions as a drive source of a rod 50 that drives the valve to open and close, and in the present embodiment, an air actuator is used.

[0017] The actuator 10 houses a drive mechanism 20 such as a piston 21 inside a housing 11. The drive mechanism 20 has the piston 21 that presses the rod 50 in a valve closing direction, a spring 24 that applies a force to the piston 21 in the valve closing direction, and an air connection portion 25 that becomes a connection portion with an air supply source.

[0018] <About the piston 21 of the actuator 10> The piston 21 has a first piston 22 and a second piston 23 that divide an air chamber 26, 27 into two with a partition wall 12 provided inside the housing 11 interposed therebetween.

[0019] The first piston 22 has a flange portion 22a that forms a flange-like wall that separates the inside of the housing 11 on the upper side with respect to the partition wall 12, and a protruding and provided shaft portion 22b that is protruding and provided on the central upper surface side of the flange portion 22a.

[0020] The second piston 23 has a flange portion 23a that forms a flange-like wall that separates the inside of the housing 11 on the lower side with respect to the partition wall 12, a piston side protruding and provided shaft portion 23b that is protruding and provided on the central upper surface side of the flange portion 23a, and a rod side protruding and provided shaft portion 23c that is protruding and provided on the central lower surface side of the flange portion 23a.

[0021] The piston side protruding and provided shaft portion 23b protrudes into the air chamber 26 on the first piston 22 side through a through hole 12a formed in the center of the partition wall 12, and abuts against the flange portion 22a of the first piston 22.

[0022] The rod side protruding and provided shaft portion 23c is in sliding contact with the inner peripheral surface of a guide hole 91 of the coupling member 90, the distal end surface 23d thereof abuts against the rod 50, and the inner peripheral surface of the guide hole 91 of the coupling member 90 is reduced in diameter compared to the inner peripheral surface of the housing 11 with which the flange portion 23a of the second piston 23 is in sliding contact.

[0023] Such first and second pistons 22 and 23 have O-rings 22c and 23e fitted to the outer peripheral surfaces of the flange portions 22a and 23a, the protruding shaft portions 22b and 23b, and the rod-side protruding shaft portion 23c. The first and second pistons 22 and 23 are able to be airtightly closed between the inner peripheral surface of the housing 11 and simultaneously moved in the axial direction via the O-rings 22c and 23e.

[0024] Such first and second pistons 22 and 23 have the flow path 28 formed in the respective interiors coupled, forming a continuous flow path 28 connecting the air chambers 26 and 27 from the air connection portion 25. The piston 21 is moved downward in the closing valve direction via the flange portion 22a of the first piston 22 pressed by the spring force of the spring 24 in a state where air is not supplied to the air chambers 26 and 27.

[0025] On the other hand, if air is supplied from the air supply source via the air connection portion 25, the air is filled into the air chambers 26 and 27 through the flow path 28 formed in the piston 21. Thereby, the piston 21 is moved upward in the opening valve direction against the spring force of the spring 24 by the pressure of the air filled into the air chambers 26 and 27.

[0026] <About the valve body 30> The valve body 30 has a main body 40, a rod 50, a diaphragm 60 disposed in contact with and separation from a valve seat 44 in the main body 40, a diaphragm member 70, and a holding member 80 holding the diaphragm member 70 movably in the axial direction of the diaphragm member 70.

[0027] <About the main body 40> The main body 40 is composed of, for example, a stainless steel material, and has an appearance of a substantially rectangular parallelepiped shape. The main body 40 is formed with a primary side flow path 41 on the upstream side through which a control fluid flows in and a secondary side flow path 42 on the downstream side through which the control fluid flows out, and is provided with a ring-shaped valve seat 44 on an opening edge surface through which the primary side flow path 41 is made to pass upward and open toward a valve chamber 43.

[0028] <About the rod 50> The rod 50 has an appearance of a substantially cylindrical shape, and one end portion is in abutment with the rod-side protruding shaft portion 23c of the second piston 23, and the other end portion is in abutment with the diaphragm member 70. The rod 50 is provided with two diameter-expanded portions 51 and 52 between the one end side and the other end side thereof. The outer peripheral surfaces of the two diameter-expanded portions 51 and 52 of the rod 50, which are provided separately in the axial direction, are in sliding contact with the inner peripheral surface of the guide hole 91 of the coupling member 90 and are guided in the up-and-down direction. In addition, the rod 50 is arranged in the guide hole 91 with a gap T1 as a clearance so that the rod 50 can be inserted and removed from the guide hole 91 in consideration of disassembly and assembly. Figure 4 、 5 ). The rod 50 also includes a contact portion 53 having an outer diameter smaller than that of the enlarged diameter portions 51 and 52 and protruding downward from the lower enlarged diameter portion 52 . The contact portion 53 serves as the distal end of the rod 50 inserted into the recess 71 of the diaphragm 70. The distal end of the rod 50 may be sized to at least have an outer diameter and an axial length sufficient to be inserted into the recess 71 of the diaphragm 70. The contact portion 53 has a spherical distal end surface 53 a that contacts the inner bottom surface 71 a of the recessed portion 71 of the diaphragm 70 .

[0029] <About Separator 60> The diaphragm 60 is substantially disc-shaped and made of metal such as nickel / cobalt alloy. Its outer peripheral edge 60 a is held and fixed by a step 45 formed on the inner peripheral surface of the main body 40 and a lower outer peripheral edge 80 a of the holding member 80 . In this embodiment, when the diaphragm 60 is assembled in the main body 40, the outer peripheral edge portion 60a of the diaphragm 60 is placed on the step portion 45 of the main body 40, and then the lower end outer peripheral edge portion 80a of the retaining member 80 is placed from above the diaphragm 60 so as to overlap with the outer peripheral edge portion 60a of the diaphragm 60. Then, with the outer peripheral edge portion 60a of the diaphragm 60 sandwiched between the step portion 45 and the retaining member 80, the coupling member 90 is screwed into the main body 40, thereby clamping and fixing the diaphragm 60 in the main body 40. The diaphragm 60 having the outer peripheral edge portion 60 a fixed thereto can elastically deform such that the region inside the outer peripheral edge portion 60 a can be brought into contact with and separated from the valve seat 44 .

[0030] <About Diaphragm 70> like Figure 3 and Figure 7 As shown, the diaphragm material 70 is a member formed by performing countersinking on one end surface of a cylindrical metal member to form a concave portion 71 having a circular outer shape. In addition, the recessed portion 71 may be formed by a processing method other than countersinking. For example, the recessed portion 71 may be formed by metal mold molding.

[0031] The inner bottom surface 71a of the recessed portion 71 has a curvature radius R2 that is smaller than the curvature radius R1 of the distal end surface 53a of the rod 50 (see Figure 6 ) is larger and spherical with the center as the lowest surface. Thus, the rod 50 can maintain a state in which the tip face 53a abuts against the inner bottom face 71a of the recess 71 while simultaneously performing centering movement along the inner bottom face 71a. In addition, as Figure 5 indicated, the recess 71 is set to a size that forms a gap S in which the abutting portion 53 of the rod 50 can perform centering movement within the recess 71.

[0032] In addition, the inner bottom face 71a of the recess 71 is formed at a position that is deeper within limits in which a prescribed strength can be ensured. Further, the "position that is deeper within limits in which a prescribed strength can be ensured" in the present embodiment refers to a depth D in which, within limits in which the strength determined in relation to the height H of the axis direction of the diaphragm member 70 and the depth D of the inner bottom face 71a set to a prescribed depth with respect to the height H satisfies, for example, the durability performance required of a valve, the ratio with respect to the height H is set to be as large as possible.

[0033] <Regarding the Retaining Member 80> The retaining member 80 is a member that retains the diaphragm member 70 so as to be freely movable in the axis direction of the diaphragm member 70. In addition, as described above, the retaining member 80 is also a member that sandwiches and fixes the outer peripheral portion 60a of the diaphragm 60 from above the stepped portion 45 of the main body 40. The retaining member 80 is generally cylindrical in appearance, and a guide hole 81 that freely retains the diaphragm member 70 so as to be freely movable in the axis direction is formed in the central portion that is the axis. The diaphragm member 70 is disposed within the guide hole 81 so as to have a clearance T2 that is a slight play in the radial direction with respect to the guide hole 81, taking into consideration the disassembly / assembly property of being freely inserted and removed with respect to the guide hole 81 and the amount of movement for centering (refer to Figure 5 ).

[0034] Here, the diaphragm member 70 has a height H in the axis direction that is guided by the retaining member 80 with the side portion outer peripheral surface 70a of the diaphragm member 70 as a sliding surface. That is, the diaphragm member 70 has a height H that is necessary for being stably guided in the axis direction by the retaining member 80. Furthermore, the guide hole 81 of the retaining member 80 is set to a size that is necessary for stably guiding the side portion outer peripheral surface 70a of the diaphragm member 70 having such a height H in the axis direction. More specifically, the guide hole 81 is set to a height that is substantially equal to the diaphragm member 70 in the axis direction.

[0035] <Regarding the Coupling Member 90> The coupling member 90 is a member that couples the actuator 10 with the valve body 30. The upper end of the coupling member 90 is threadedly engaged with the lower end of the housing 11 of the actuator 10 to be coupled to the housing 11. In addition, the lower end of the coupling member 90 is threadedly engaged with the upper end of the valve body 30 to be coupled to the body 40. Furthermore, the lower end surface of the coupling member 90 abuts against the upper end surface of the holding member 80, and as a fastening operation based on the thread engagement of the coupling member 90 with the body 40 is performed, the coupling member 90 presses the holding member 80 downward, whereby the outer peripheral portion 60a of the diaphragm 60 is clamped and fixed between the stepped portion 45 of the body 40 and the lower end outer peripheral portion 80a of the holding member 80.

[0036] <Regarding the moment acting on the diaphragm 70 when the diaphragm 70 is pressed in a state where the stem 50 is inclined> Next, the moments acting on the diaphragm 70, 170 when the diaphragm 70, 170 is pressed in a state where the stem 50 is inclined will be described using Figure 8A and Figure 8B Fig. 8(A) shows the diaphragm 70 whose inner bottom surface 71a is spherical, and Fig. 8(B) shows the diaphragm 170 whose inner bottom surface 171a is planar. Regarding the diaphragm 70 shown in Fig. 8(A), the spherical inner bottom surface 71a has a depth equal to that of the planar inner bottom surface 171a of Fig. 8(B) at the outer periphery, and the depth increases in a spherical shape with the central portion as the deepest portion from the outer periphery. Further, in Figs. 8(A), (B), the diaphragm 60 disposed between the diaphragm 70, 170 and the valve seat 44 is omitted for simplicity of explanation, and regarding the force acting on the diaphragm 60, the explanation thereof is omitted.

[0037] As shown in Figs. 8(A), (B), if the inner bottom surface 71a, 171a of the diaphragm 70, 170 is pressed in a state where the stem 50 is inclined, a force F inclined downward with respect to the vertical direction acts on the inner bottom surface 71a. Furthermore, the force F acting in this inclined direction is decomposed into a horizontal force Fl and a vertical force F2. Therefore, for example, a moment that rotates the diaphragm 70, 170 counterclockwise with the left side of the drawing of the valve seat 44 as a fulcrum acts on the diaphragm 70, 170. If such a moment acts on the diaphragm 70, 170, the diaphragm 70, 170 moves away from the fulcrum on the right side of the drawing of the valve seat 44, and thus the force with which the diaphragm 70, 170 presses the valve seat 44 becomes uneven.

[0038] ​Here, if the distance in the vertical direction from the valve seat 44 serving as a fulcrum to the position at which the rod 50 abuts against the inner bottom surface 71a, 171a is r, the moment M is expressed by the formula M = Fl x r.

[0039] Thus, in the configuration of Fig. 8(A) in which the inner bottom surface 71a of the diaphragm member 70 is formed in a spherical shape, the moment Ml acting on the diaphragm member 70 becomes Ml = Fl x rl. Further, in the configuration of Fig. 8(B) in which the inner bottom surface 171a of the diaphragm member 170 is formed in a flat surface, the moment M2 acting on the diaphragm member 170 becomes M2 = Fl x r2. Here, according to the relationship of r2 > rl, M2 > Ml is obtained. That is, it is understood that, as compared with the case in which the inner bottom surface 171a of the diaphragm member 170 is formed in a flat surface, the case in which the inner bottom surface 71a is formed in a spherical shape can suppress the moment acting on the diaphragm member 70, 170 to be small, and can suppress the deviation of the force by which the diaphragm member 70, 170 presses the valve seat 44 to be small, and as a result, can improve the alignment performance of the diaphragm member 70, 170 with respect to the valve seat 44.

[0040] Due to such a situation, the present inventors et al. found that the more the moment acting on the diaphragm member 70 is reduced, the more the alignment performance is improved, and in order to reduce the moment, the distance r in the vertical direction from the valve seat 44 serving as a fulcrum to the position at which the rod 50 presses the inner bottom surface 71a is reduced. That is, it was found that the depth of the inner bottom surface 71a of the diaphragm member 70 is made deeper, and it was found that the inner bottom surface 71a is formed in a spherical shape in such a manner that the vicinity of the axis of the inner bottom surface 71a of the diaphragm member 70 is the deepest, and the alignment performance is further improved. Further, the present inventors et al. also found that, by forming the inner bottom surface 71a of the diaphragm member 70 in a spherical shape, it is possible to make the tip end of the rod 50 intrude into a deeper position of the recess 71 of the diaphragm member 70, and it is possible to further compact the device size in the axial direction of the rod 50.

[0041] Next, the difference in the alignment performance caused by the difference in the depth of the inner bottom surface 71a of the recess 71 in the case in which the diaphragm member 70 is tilted in correspondence with the valve seat 44 which is slightly tilted due to assembly tolerance will be described using Figure 9 , Figure 10A and Figure 10B .

[0042] First, the case in which the inclination of the inner bottom surface 71a pressed by the rod 50 changes in correspondence with the depth of the inner bottom surface 71a in the state in which the diaphragm member 70 is tilted will be described using Figure 9 . In Figure 9In the middle, the diaphragm member 70 is shown as being inclined in correspondence with the valve seat 44 being slightly inclined due to assembly tolerance. Further, the broken lines L1 to L4 shown in the drawing show that the plurality of inner bottom surfaces 71a of the diaphragm member 70 vary in depth for a given height. In addition, the broken line C2 shows the positions of the inner bottom surfaces 71a that the rod 50 presses at different depths as the intersection points of the broken lines L1 to L4. In addition, the solid lines S1 to S4 show the inclination of the inner bottom surface 71a at the position pressed by the rod 50. In addition, the positions P1 to P4 show the lowest positions of each of the inner bottom surfaces 71a at the state in the drawing that vary in depth. In addition, the solid line C1 shows the axis of the diaphragm member 70.

[0043] As shown in Figure 9 it is understood that, in the state in which the diaphragm member 70 is slightly inclined, the inclination of the inner bottom surface 71a at the position of the press by the rod 50 becomes smaller with respect to the case in which the inner bottom surface 71a of the diaphragm member 70 is formed at a deeper position. In addition, it is understood that, with respect to the case in which the inner bottom surface 71a is formed at a deeper position, the lowest positions P1 to P4 of the inner bottom surface 71a are closer to the axis C1 of the diaphragm member 70.

[0044] Such a change in the inclination of the inner bottom surface 71a at the position of the press by the rod 50 and a change in the lowest position of the inner bottom surface 71a due to a difference in the depth of the inner bottom surface 71a incur a difference in the centering performance as follows. That is, as shown in FIG. 10(A), with respect to the diaphragm member 70 in which the inner bottom surface 71a is formed at a shallow position, the inclination of the inner bottom surface 71a contacted by the rod 50 is larger than others, and the lowest position P1 of the inner bottom surface 71a of the diaphragm member 70 becomes a position that is farther from the axis C1 than others. Therefore, the rod 50 easily slides on the inner bottom surface 71a toward the lowest position P1, easily moves along the inner bottom surface 71a toward the lowest position P1 that is farther from the axis C1 of the diaphragm member 70, and as a result, the press position of the rod 50 on the inner bottom surface 71a moves to a position that is farther from the axis C1 of the diaphragm member 70.

[0045] Thus, if the press position of the rod 50 moves to a position that is farther from the axis C1 of the diaphragm member 70, the rod 50 presses the diaphragm member 70 at a position that is farther from the axis C1 of the diaphragm member 70 than others. Therefore, with respect to the diaphragm member 70 in which the inner bottom surface 71a is formed at a shallow position, the load with which the diaphragm member 70 presses the valve seat 44 becomes uneven compared to the diaphragm member 70 in which the inner bottom surface 71a is formed at a deeper position, and the centering performance is poor.

[0046] On the other hand, as shown in FIG10(B), with respect to the diaphragm member 70 in which the inner bottom surface 71a is formed at a deeper position, the inclination of the inner bottom surface 71a with which the rod 50 contacts is smaller than that of the others, and the lowest position P4 of the inner bottom surface 71a of the diaphragm member 70 becomes a position closer to the axis C1 than that of the others. Therefore, when the rod 50 moves toward the lowest position P4 on the inner bottom surface 71a, the position where the rod 50 presses against the inner bottom surface 71a easily moves to a position closer to the axis C1 of the diaphragm 70, making it possible to make the load pressing the valve seat 44 via the diaphragm 70 more uniform compared to other diaphragms. Therefore, compared to a diaphragm 70 in which the inner bottom surface 71a is formed at a shallow position, the centering performance is excellent.

[0047] <About the Valve Opening and Closing Operation of Diaphragm Valve 1> Next, the valve opening and closing operation of the diaphragm valve 1 will be described. Figure 1 The diaphragm valve 1 in the shown open state is in a state where the piston 21 moves upward against the downward elastic force of the spring 24 by the driving force of the air filled in the air chambers 26 and 27 . In this valve-open state, the diaphragm 60 is released from the pressing force of the rod 50 via the diaphragm material 70 and enters an elastically neutral state, and is separated from the valve seat by bulging upward.

[0048] If the air supply to the diaphragm valve 1 in the open state is stopped, the air is discharged from the air chambers 26 and 27, and the force that resists the elastic force of the spring 24 and causes the piston 21 to rise is weakened, and the elastic force of the spring 24 presses the piston 21 downward. Then, the rod 50 abutting against the rod-side protruding shaft portion 23 c of the second piston 23 is pushed downward as the piston 21 descends. As a result, the rod 50 moves downward while being guided by the guide hole 91 of the coupling member 90 , and the spherical distal end surface 23 d presses the inner bottom surface 71 a of the diaphragm 70 , pushing the diaphragm 70 downward. At this time, the diaphragm 70 moves downward while being guided in the axial direction by the holding member 80 . Here, the diaphragm 70 is set to a height at which it can be stably guided in the axial direction by the holding member 80 , and thus moves downward while being stably guided by the holding member 80 . By pushing the diaphragm member 70 downward in this manner, the diaphragm 60 is pressed downward, deformed so that the central portion thereof is elastically concave, and thereby comes into close contact with the valve seat 44. The diaphragm valve 1 is Figure 2 The valve is shown in the closed state.

[0049] In this case, in the case where the rod 50 presses the diaphragm member 70 in the inclined state while pressing the diaphragm member 70 downward, although the moment acts on the diaphragm member 70 as described above, by forming the inner bottom surface 71a of the diaphragm member 70 in a spherical shape, it is possible to make the position at which the rod 50 presses the inner bottom surface 71a a deeper position of the diaphragm member 70, and it is possible to make the distance from the valve seat 44 in the vertical direction smaller, and as a result, it is possible to make the moment acting on the diaphragm member 70 smaller and improve the centering performance.

[0050] In addition, in the case where the valve seat 44 is inclined due to assembly tolerance or the like, the diaphragm member 70 presses the valve seat 44 in a state inclined in correspondence with the inclination of the valve seat 44. In this case, as described above, by forming the inner bottom surface 71a of the diaphragm member 70 at a deeper position, it is possible to make the pressing position of the rod 50 on the inner bottom surface 71a be in the vicinity of the axis C1 of the diaphragm member 70, and thus it is possible to further improve the centering performance.

[0051] <Effects of Embodiments> As described above, according to the diaphragm valve 1 according to the embodiments, the tip surface 53a of the rod 50 is in a spherical shape, and in the diaphragm member 70, a recess 71 into which the abutting portion 53 as the tip portion of the rod 50 is interposed is provided, and the inner bottom surface 71a of the recess 71 is in a spherical shape having a central portion as a lowest surface and a curvature radius R2 larger than the curvature radius R1 of the tip surface 53a of the rod 50. Thus, in order to close the valve, when the tip surface 53a of the rod 50 presses the inner bottom surface 71a of the recess 71 of the diaphragm member 70, the rod 50 makes the spherical tip surface 53a abut on the spherical inner bottom surface 71a of the recess 71, and at the same time, moves toward the lowest surface of the inner bottom surface 71a. Therefore, when the position at which the rod 50 presses the diaphragm member 70 becomes a position closer to the valve seat 44, and the rod 50 is inclined to press the inner bottom surface 71a of the diaphragm member 70 separate from the rod 50, the moment that rotates the diaphragm member 70 is made smaller, and it is possible to prevent the diaphragm member 70 from being greatly inclined due to play of assembly tolerance and degradation of the centering performance. Therefore, in the configuration having assembly tolerance that is assembled and disassembled freely, even in the case where the sealing force against the valve seat 44 is made smaller, it is possible to improve the centering performance of the diaphragm member 70, and maintain the sealing performance of the valve seat 44, and further improve the sealing performance of the valve seat 44.

[0052] Further, according to the diaphragm valve 1 of the embodiment, the inner bottom surface 71a of the recess 71 of the diaphragm member 70 is formed at a position deeper within a limit in which a predetermined strength can be ensured, so that the end surface 53a of the rod 50 is pressed against the inner bottom surface 71a at a position deeper in the recess 71, and the rod 50 presses the inner bottom surface 71a at a position closer to the valve seat 44, and thus it is possible to suppress the moment acting on the diaphragm member 70 when the rod 50 is tilted to press the inner bottom surface 71a of the recess 71 while ensuring the strength of the diaphragm member 70. Further, it is possible to fit the abutting portion 53, which is the end portion of the rod 50, into the position deeper in the recess 71 of the diaphragm member 70, and as a result, it is possible to make the device size in the axial direction of the rod 50 compact. Further, even in the case where the valve seat 44 is tilted due to assembly tolerance, it is possible to make the pressing position of the rod 50 against the inner bottom surface 71a be in the vicinity of the center axis C1 of the diaphragm member 70, and thus it is possible to further improve the alignment performance.

[0053] Further, according to the diaphragm valve 1 of the embodiment, there is a holding member 80 that holds the diaphragm member 70 so as to be movable in the axial direction, and the diaphragm member 70 has a height H in the axial direction that is guided by the holding member 80 with the side portion outer peripheral surface 70a of the diaphragm member 70 as a sliding surface. Thus, by stably ensuring the height of the sliding surface for guidance of the diaphragm member 70 against the holding member 80 in the axial direction of the diaphragm member 70, and at the same time, by fitting the abutting portion 53, which is the end portion of the rod 50, into the position deeper in the recess 71 of the diaphragm member 70, the position at which the rod 50 presses the diaphragm member 70 becomes a position closer to the valve seat 44. Therefore, it is possible to stably guide the diaphragm member 70 so as to be movable in the axial direction, and at the same time, suppress the moment acting on the diaphragm member 70 to be small.

[0054] The above describes the embodiments of the present disclosure, but the present disclosure is not limited to the above-described embodiments, and various changes can be made without departing from the gist thereof.

[0055] For example, in the above-described embodiments, the diaphragm valve is exemplified as a normally closed type valve, but the diaphragm valve can also be a normally open type. Further, the diaphragm valve can also be an automatic type valve using an actuator, or a manual type valve using a handle.

[0056] It should be considered that each of the embodiments disclosed herein is illustrative and not restrictive in all aspects. The above-described embodiments can be omitted, replaced, or changed in various ways without departing from the appended claims and the gist thereof. Explanation of Reference Signs

[0057] 1 diaphragm valve 44 valve seat 50 stem 53a end surface 60 diaphragm 70 diaphragm member 70a side outer peripheral surface 71 recess 71a inner bottom surface 80 holding member

Claims

1. A diaphragm valve having a diaphragm member arranged at the tip of a stem so as to abut thereagainst, and a valve-closing state in which the diaphragm is brought into abutment with a valve seat via the diaphragm member being pushed in the valve-closing direction by the stem, characterized in that, the tip surface of the stem is spherical, a recess in which the tip portion of the stem is fitted is provided in the diaphragm member, and the inner bottom surface of the recess is spherical with a central portion as the lowest portion, and has a larger radius of curvature than the radius of curvature of the tip surface of the stem.

2. The diaphragm valve according to claim 1, wherein the inner bottom surface of the recess is formed at a position deeper within a limit in which a predetermined strength can be ensured.

3. The diaphragm valve according to claim 1 or 2, wherein a holding member that holds the diaphragm member so as to be freely movable in the axial direction of the diaphragm member is provided, and the diaphragm member has a height in the axial direction that is guided by the holding member in the axial direction with the side surface outer peripheral surface of the diaphragm member as a sliding surface. ​ ​ ​ ​ ​ ​

Images