Valve device

Abstract

To provide a valve device which can improve workability, durability and airtightness.SOLUTION: A valve device 1 comprises: a valve main body 10 having a valve port 17; a valve body 50 approaching or separating from the valve port 17; a drive part 60 for driving the valve body 50; a screw-feeding mechanism 70 for transmitting a drive force of the drive part 60 to the valve body 50; and a first diaphragm 20 for maintaining airtightness in the valve main body 10. The screw-feeding mechanism 70 comprises: a spindle 71 rotating around an axis; and a female screw member 72 connected to the spindle 71 and also connected to the valve body 50. The female screw member 72 is displaced in a displacement direction of the valve body 50 by the rotation of the spindle 71 in a state that the rotation around the axis is regulated. The first diaphragm 20 is provided over the valve main body 10 and the female screw member 72, and is displaced in the displacement direction conforming to the displacement of the female screw member 72.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] A valve device that adjusts the flow rate of a fluid flowing through a valve port is known (see, for example, Patent Document 1). The valve device described in Patent Document 1 includes a housing, a valve port provided in the housing, and a valve body that increases and decreases the effective opening area of ​​the valve port. In this valve device, the valve body is integrally formed coaxially with a valve shaft member that is inserted into the valve port. A part of the valve shaft member is located in a guide hole that extends in the axial direction of a cylindrical member fixed to the housing. A male thread is formed on the outer circumferential surface of the valve shaft member, and the male thread is screwed into a female thread formed on the inner circumferential surface of the guide hole. In addition, an O-ring for airtightness is installed between a part of the outer circumferential surface of the valve shaft member that does not have the male thread and the inner circumferential surface of the guide hole, and the O-ring prevents the fluid from entering the guide hole. The valve shaft member moves in the axial direction while being rotated around the axis by a stepping motor, and the valve body moves in the axial direction accordingly. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-266403 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned valve device, when the valve shaft member rotates around the axis and moves in the axial direction, the outer peripheral surface of the O-ring and the inner peripheral surface of the guide hole slide around the axis and in the axial direction, and the operability of the valve shaft member is reduced due to the sliding resistance. In addition, the O-ring is worn out by the sliding, and the durability of the valve shaft member is likely to be reduced. In addition, the wear causes a gap between the outer peripheral surface of the O-ring and the inner peripheral surface of the guide hole, and fluid flows into the guide hole through the gap, which tends to reduce the reliability of the airtightness of the valve device.

[0005] An object of the present invention is to provide a valve device that can achieve improved operability, durability, and airtightness. [Means for solving the problem]

[0006] In order to solve the above problems and achieve the object, the valve device of the present invention comprises a valve body having a valve port, a valve disc that moves toward or away from the valve port inside the valve body, a drive unit that drives the valve disc, a screw feed mechanism that transmits the drive force of the drive unit to the valve disc, and a sealing member that maintains airtightness inside the valve body, wherein the screw feed mechanism comprises a first screw feed member that rotates about an axis by the drive force, and a second screw feed member that is connected to the first screw feed member and also to the valve disc, the second screw feed member being displaced in the displacement direction of the valve disc by the rotation of the first screw feed member while its rotation about the axis is restricted, and the sealing member is provided across the valve body and the second screw feed member, and deforms in the displacement direction in accordance with the displacement of the second screw feed member.

[0007] According to the present invention, the sealing member provided between the valve body and the second screw feed member maintains the airtightness of the inside of the valve body, thereby preventing fluid leakage into unintended parts of the valve device, and improving the reliability of the airtightness of the valve device. When the valve body is driven, the second screw feed member is displaced in the displacement direction of the valve body by the rotation of the first screw feed member, but since the rotation of the second screw feed member around the axis is restricted, the rotational force of the drive unit is not transmitted to the sealing member. Therefore, it is possible to prevent the occurrence of sliding resistance around the axis between the sealing member and the valve body. Therefore, it is possible to suppress the application of a load in the rotation direction to the first screw feed member and the second screw feed member, and to improve the operability of the valve body. In addition, since the sealing member does not slide around the axis relative to the valve body, wear of the sealing member can be suppressed. In addition, since the sealing member deforms in the displacement direction of the valve body in accordance with the displacement of the second screw feed member, the displacement of the second screw feed member can be absorbed by the deformation of the sealing member. Therefore, it is not necessary to slide the sealing member in the displacement direction relative to the valve body, and wear of the sealing member can be suppressed. By suppressing wear of the sealing member in this way, the durability of the valve device can be improved. Therefore, it is possible to provide a valve device that can improve operability, durability, and airtightness.

[0008] In this case, it is preferable that the valve body is provided with a guide member along which the second screw feed member slides in the displacement direction. According to this configuration, the second screw feed member can be slid along the guide member and guided in the displacement direction, so that tilt and rattling of the second screw feed member with respect to the displacement direction can be suppressed, and the drive of the valve body can be stabilized.

[0009] In addition, it is preferable that the guide member is provided with a guide surface parallel to the displacement direction, and the second screw feed member is provided with a guided surface that slides on the guide surface. According to this configuration, the guided surface of the second screw feed member is slid on the guide surface of the guide member, so that the displacement of the second screw feed member in the displacement direction can be reliably guided. Therefore, the driving of the valve body can be made even more stable. Also, according to this configuration, since the guided surface abuts on the guide surface, the rotation of the second screw feed member around the axis can be restricted by the guide surface. Therefore, it is possible to prevent the occurrence of sliding resistance around the axis between the sealing member and the valve body, and it is possible to suppress the application of a load in the rotation direction to the first screw feed member and the second screw feed member. Also, since the sealing member does not slide around the axis relative to the valve body, it is possible to suppress wear of the sealing member due to the sliding.

[0010] Also, the guide surface and the guided surface are each characterized in that at least two or more are provided. According to such a configuration, by sliding at least two or more guide surfaces on at least two or more guided surfaces, the displacement of the second screw feed member in the displacement direction can be guided at at least two points. Therefore, the drive of the valve body can be further stabilized. Furthermore, the abutment of the guided surface and the guide surface can restrict the rotation of the second screw feed member around the axis at at least two points, so that the sliding of the sealing member around the axis relative to the valve body described above can be reliably prevented, and the application of a load in the rotation direction to the first screw feed member and the second screw feed member can be reliably suppressed. Furthermore, wear of the sealing member due to the sliding can be reliably suppressed.

[0011] In addition, the sealing member may be a diaphragm. According to this configuration, the valve device of the present invention can be configured using a diaphragm as the sealing member.

[0012] The sealing member may be a bellows. According to this configuration, the valve device of the present invention can be configured by using the bellows as the sealing member. Effect of the Invention

[0013] According to the present invention, it is possible to provide a valve device that can achieve improved operability, durability, and airtightness. [Brief description of the drawings]

[0014] [Figure 1] 1 is a cross-sectional view showing a valve closed state of a valve device according to a first embodiment of the present invention. [Diagram 2] 2 is a cross-sectional view showing the valve device shown in FIG. 1 in an open state. [Diagram 3] 2 is a cross-sectional view taken along line AA in FIG. 1. [Figure 4] FIG. 4 is a cross-sectional view showing a valve closed state of a valve device according to a first modified example of the first embodiment. [Diagram 5] 5 is a cross-sectional view showing the valve device shown in FIG. 4 in an open state. [Figure 6] 5 is a cross-sectional view taken along line BB in FIG. 4 . [Figure 7] FIG. 11 is a cross-sectional view showing a valve closed state of a valve device according to a second modified example of the first embodiment. [Figure 8] 8 is a cross-sectional view showing the valve device shown in FIG. 7 in an open state. [Figure 9] FIG. 11 is a cross-sectional view showing a valve closed state of a valve device according to a second embodiment. [Figure 10] 10 is a cross-sectional view showing the valve device shown in FIG. 9 in an open state. [Figure 11] 10 is a cross-sectional view taken along line CC in FIG. 9 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, a valve device 1 according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 3. The valve device 1 is a device disposed in a part of a piping through which a fluid such as a liquid or a gas flows, and is used to adjust the flow rate of the fluid. In the following description, the direction along the axis L of a spindle 71 (first screw feed member) and an internally threaded member 72 (second screw feed member) described later will be referred to as the "axis L direction". One side of the axis L direction will be referred to as the "upper side L1", and the other side will be referred to as the "lower side L2". A direction intersecting the axis L direction will be referred to as the "crossing direction X". One side of the crossing direction X will be referred to as the "left side X1", and the other side will be referred to as the "right side X2". These definitions are merely for convenience of description, and do not necessarily correspond to the directions in the actual use state of the valve device 1, and do not limit the directions of the valve device 1.

[0016] As shown in Fig. 1, the valve device 1 includes a valve body 10 having a valve port 17 through which a fluid passes, a valve element 50 that approaches or moves away from the valve port 17 in the axial direction L (displacement direction) inside the valve body 10, a drive unit 60 that drives the valve element 50, and a screw feed mechanism 70 that transmits the drive force of the drive unit 60 to the valve element 50. The valve body 10 includes a cylindrical main body 11 that extends in the intersecting direction X. A first port 12 that opens in the intersecting direction X is formed at an end of the left side X1 of the main body 11. A second port 13 that opens in the intersecting direction X is formed at an end of the right side X2 of the main body 11. A partition wall 14 that extends along the axial line A of the main body 11 and divides the inside of the main body 11 into upper and lower parts is disposed inside the main body 11. The partition wall 14 extends in the transverse direction X inside the main body 11 and is supported by a left vertical wall 15 extending from its left side X1 end to the inner wall of the upper side L1 of the main body 11, and a right vertical wall 16 extending from its right side X2 end to the inner wall of the lower side L2 of the main body 11. A valve port 17 penetrating in the axial L direction is formed in the center of the partition wall 14, and a valve seat portion 18 protruding to the upper side L1 around the entire circumference of the valve port 17 is formed at the edge of the upper side L1 of the valve port 17.

[0017] A first diaphragm 20 (sealing member) that seals the upper through-hole 19 penetrating in the axial direction L is installed on the wall surface of the upper side L1 of the main body 11. The first diaphragm 20 is formed in a plate shape using a resin member that is elastically deformable in the axial direction L, and maintains airtightness inside the main body 11 (valve main body 10) by sealing the upper through-hole 19 of the main body 11. The lower surface of the outer edge side of the first diaphragm 20 abuts on the wall surface of the upper side L1 of the main body 11. The upper surface of the center part of the first diaphragm 20 abuts on the lower surface of the lower cylindrical portion 80 of the female screw member 72 described later. In other words, the first diaphragm 20 is provided across the valve main body 10 and the female screw member 72.

[0018] A first pressing part 21 that fixes the first diaphragm 20 to the main body 11 is provided on the upper side L1 of the first diaphragm 20. The first pressing part 21 is formed in a cylindrical shape that opens to the upper side L1. A first protrusion 23 that protrudes to the lower side L2 is formed on the bottom surface 22 of the first pressing part 21, and the first protrusion 23 is in a state where it bites into the upper surface of the first diaphragm 20, and the bottom surface 22 presses the upper surface of the first diaphragm 20 to the lower side L2, thereby fixing the first diaphragm 20 to the main body 11. An inclined surface 24 is formed in the center of the first pressing part 21, which is inclined to be located on the upper side L1 as it approaches the center. Due to the formation of the inclined surface 24, a gap is generated in the axial direction between the first pressing part 21 and the center of the first diaphragm 20, and this gap becomes a deformation allowance of the first diaphragm 20 to the upper side L1. A through hole 25 penetrating in the axial direction L is formed in the center of the first pressing portion 21.

[0019] A sleeve 26 supporting the lower cylindrical portion 80 of the female screw member 72 is installed on the edge of the through hole 25. The sleeve 26 is formed in an annular shape extending in the axial line L direction, and the lower cylindrical portion 80 of the female screw member 72 is inserted inside. A recess 27 recessed radially inward is formed on the outer circumferential surface of the sleeve 26. The recess 27 is a portion that fits into the edge of the through hole 25. An annular pressing spring 28 is arranged around the entire circumference on the inner surface of the recess 27. The lower end of the pressing spring 28 abuts against the upper edge of the through hole 25 that is fitted into the recess 27, and presses the upper edge against the inner surface of the recess 27. This fixes the sleeve 26 to the first pressing portion 21. A guide member 29 supporting the screw feed mechanism 70 is installed on the upper side L1 of the first pressing portion 21. The guide member 29 comprises a top wall 30 facing the first diaphragm 20 in the axial direction L, a side wall 31 extending from the outer edge of the top wall 30 to the downward side L2 and abutting the upper surface of the first pressing portion 21, and a pair of guide portions 32 extending from the center of the top wall 30 to the downward side L2.

[0020] A plate-shaped bracket 33 is disposed on the upper surface of the top wall 30. A first set screw 34 is fixed to the bracket 33, which extends in the axial direction L through the bracket 33, the top wall 30, the first pressing portion 21, and the first diaphragm 20, and the guide member 29 is fixed to the main body 11 by the first set screw 34. A first through hole 35 penetrating in the axial direction L and a second through hole 36 continuing to a lower side L2 of the first through hole 35 are formed in the center of the top wall 30. The first through hole 35 opens on the upper surface of the top wall 30. The second through hole 36 is formed with a smaller diameter than the first through hole 35, and communicates with the first through hole 35 and also communicates with a space sandwiched between the pair of guide portions 32. The side wall 31 extends in the axial direction L between the top wall 30 and the first pressing portion 21. The side wall 31 may be cylindrical in shape by surrounding the outer edge of the top wall 30 around the axis L, or may be columnar in shape by hanging down from a part of the top wall 30.

[0021] As shown in FIG. 3, two guide parts 32 (a pair) are formed at an interval in the transverse direction X. A guide surface 37 that slides on the guided surface 78a of the female screw member 72 is formed on the inner side of the guide part 32 in the transverse direction X. The guide surface 37 extends parallel to the axis L direction. In this embodiment, the guide surface 37 is formed on the inner part of the pair of guide parts 32 in the transverse direction X. However, for example, the guide part 32 may be formed in a cylindrical shape and a part of its inner peripheral surface may be made a surface parallel to the axis L direction to form the guide surface 37. A second diaphragm 39 that seals the lower through hole 38 penetrating in the axis L direction is installed on the wall surface of the lower side L2 of the main body 11. The second diaphragm 39 is formed in a plate shape using a resin member that is elastically deformable in the axis L direction, and maintains airtightness inside the main body 11 (valve main body 10) by sealing the lower through hole 38 of the main body 11. The upper surface of the outer edge side of the second diaphragm 39 abuts against the wall surface of the lower side L2 of the main body 11.

[0022] The lower end surface of a support member 45 (described later) abuts against the upper surface of the center of the second diaphragm 39. A second pressing part 40 that fixes the second diaphragm 39 to the main body 11 is provided on the lower side L2 of the second diaphragm 39. The second pressing part 40 is formed in a cylindrical shape that opens to the lower side L2. A second protrusion 42 that protrudes to the upper side L1 is formed on the upper surface 41 of the second pressing part 40, and with the second protrusion 42 biting into the lower surface of the second diaphragm 39, the upper surface 41 presses the lower surface of the second diaphragm 39 against the upper side L1, thereby fixing the second diaphragm 39 to the main body 11.

[0023] A cylindrical boss portion 43 is formed in the center of the second pressing portion 40. The upper surface of the boss portion 43 abuts against the lower surface of the second diaphragm 39. A valve stem screw 44 is fixed to the center of the boss portion 43, which is inserted in the axial direction L through the boss portion 43, the valve body 50, and the first diaphragm 20. A cylindrical support member 45 that supports the valve body 50 is fixed to the outer circumferential surface of the valve stem screw 44. A support protrusion 45a that protrudes outward in the cross direction X is formed on the outer circumferential surface of the support member 45, and the upper surface of the support protrusion 45a abuts against the lower surface of the valve body 50. The lower end surface of the support member 45 abuts against the upper surface of the second diaphragm 39. As a result, the second diaphragm 39 is sandwiched in the axial direction L by the boss portion 43 and the support member 45 described above.

[0024] A valve stem male thread 46 is formed on the outer peripheral surface of the end of the upper side L1 of the valve stem screw 44, and this valve stem male thread 46 is screwed into a second female thread 82 formed on the inner peripheral surface of the lower cylindrical portion 80 of the female thread member 72. A cap 47 is installed on the lower side L2 of the second pressing portion 40 to cover the boss portion 43 and the valve stem screw 44. The cap 47 is formed in a box shape that opens to the upper side L1. A flange 48 that protrudes outward in the transverse direction X is formed on the opening edge of the cap 47, and a second set screw 49 that is inserted in the axial direction L through the flange 48, the second pressing portion 40, and the second diaphragm 39 is fixed to the flange 48.

[0025] The valve element 50 is a member that opens and closes, for example, the valve port 17 by approaching or moving away from the valve port 17 inside the valve body 10, and is formed in a thick plate shape that covers the outer circumferential surface of the support member 45 described above in the circumferential direction. As described above, the upper surface of the support protrusion 45a abuts against the lower surface of the valve element 50. Meanwhile, a plate-shaped valve cover 51 is disposed on the upper surface of the valve element 50. A cylindrical cover holder 52 extending in the axial direction L is interposed between the upper surface of the valve cover 51 and the lower surface of the first diaphragm 20. As a result, the valve element 50 is sandwiched in the axial direction L by the support protrusion 45a disposed on the lower side L2, and the valve cover 51 and the cover holder 52 disposed on the upper side L1. An O-ring 53 that seals between the inner circumferential surface of the cover holder 52 and the outer circumferential surface of the support member 45 is disposed on the upper surface of the valve cover 51. The drive unit 60 is a part that applies a rotational force as a driving force to the screw feed mechanism 70, and is constituted by, for example, a stepping motor.

[0026] The screw feed mechanism 70 is a mechanism for transmitting the driving force of the drive unit 60 to the valve body 50, and includes a spindle 71 (first screw feed member) and a female screw member 72 (second screw feed member), each of which is made of a metallic material and extends in the direction of the axis L. An upper end portion 73 of the spindle 71 is connected to the drive unit 60, thereby allowing the spindle 71 to rotate around the axis L. A large diameter portion 74 having a diameter larger than that of the other portions of the spindle 71 is formed on a lower side L2 of the upper end portion 73, and this large diameter portion 74 is located within the first through hole 35 of the guide member 29 described above.

[0027] An annular thrust washer 75 is disposed on the upper and lower surfaces of the large diameter portion 74. The upper L1 thrust washer 75 abuts against the bracket 33 described above, and is restricted from being displaced toward the upper L1. The lower L2 thrust washer 75 abuts against a step 76 formed between the first through hole 35 and the second through hole 36, and is restricted from being displaced toward the lower L2. With this configuration, the spindle 71 is rotatable about the axis L while being restricted from being displaced in the direction of the axis L. A male thread portion 77 is formed on the outer peripheral surface of the lower L2 portion of the spindle 71. The male thread portion 77 is a screw that screws into the first female thread portion 81 of the female thread member 72.

[0028] The female screw member 72 is provided coaxially with the spindle 71 and includes an upper tube portion 78 constituting an upper side L1 portion, a large tube portion 79 continuing from the upper tube portion 78 and extending to the lower side L2, and a lower tube portion 80 continuing from the large tube portion 79 and extending to the lower side L2. As shown in FIG. 3, the upper tube portion 78 is formed in a substantially cylindrical shape and is disposed between a pair of guide portions 32 of the guide member 29. Guided surfaces 78a that face the guide surfaces 37 of the guide portions 32 in the transverse direction X are formed on both end surfaces of the upper tube portion 78 in the transverse direction X. The guided surfaces 78a extend parallel to the axis L direction, similar to the guide surfaces 37. The distance in the transverse direction X from the guided surface 78a on the left side X1 to the guided surface 78a on the right side X2 is slightly smaller than the distance in the transverse direction X from the guide surface 37 on the left side X1 to the guide surface 37 on the right side X2. This allows each guided surface 78a to slide in the axial direction L relative to each guide surface 37 when the upper tube portion 78 is positioned between a pair of guide portions 32.

[0029] Furthermore, with this configuration, the guide surface 37 and the guided surface 78a come into contact with each other, so that the rotation of the upper cylindrical portion 78 (female screw member 72) around the axis L is restricted by the guide surface 37. From the viewpoint of reliably sliding the guided surface 78a along the guide surface 37 and reliably restricting the rotation of the female screw member 72, it is preferable to provide at least two guide surfaces 37, and accordingly, it is preferable to provide at least two guided surfaces 78a. A first female screw portion 81 that screws into the male screw portion 77 is formed on the inner peripheral surface of the upper cylindrical portion 78.

[0030] The large cylinder portion 79 is formed with a larger diameter than the upper cylinder portion 78 and the lower cylinder portion 80. The upper end surface of the large cylinder portion 79 can abut against the lower end surface of the guide portion 32, and this abutment restricts the displacement of the female screw member 72 toward the upper side L1. As described above, the lower cylinder portion 80 is inserted into the sleeve 26. The outer peripheral surface of the lower cylinder portion 80 can slide against the inner peripheral surface of the sleeve 26. The lower end surface of the lower cylinder portion 80 abuts against the upper surface of the first diaphragm 20. As a result, the first diaphragm 20 is sandwiched in the axis L direction by the lower cylinder portion 80 and the above-mentioned cover presser 52. A second female screw portion 82 is formed on the inner peripheral surface of the lower cylinder portion 80.

[0031] The second female thread portion 82 is screwed into the valve stem male thread portion 46 formed on the valve stem thread 44 described above. This screwing unites the female thread member 72 and the valve stem thread 44, and thus the female thread member 72 and the valve body 50 are connected via the support member 45 fixed to the valve stem thread 44. That is, the female thread member 72 is screwed into the male thread portion 77 of the spindle 71 and is connected to the valve body 50. As described above, the first diaphragm 20 is sandwiched between the cover holder 52 and the lower cylinder portion 80, and thus the female thread member 72 and the first diaphragm 20 are connected via the lower cylinder portion 80.

[0032] Next, the operation of the valve device 1 will be described. First, as shown in FIG. 1, in a valve-closed state in which the valve body 50 is seated on the valve seat portion 18 and the valve port 17 is closed, the flow of the fluid inside the main body 11 stops. From this state, the drive unit 60 is driven. Specifically, a predetermined pulse signal is transmitted to the stepping motor, and a rotational force is applied to the spindle 71 from the drive unit 60. The rotational force causes the spindle 71 to rotate around the axis L. At this time, as described above, since the displacement of the spindle 71 in the direction of the axis L is restricted, the spindle 71 does not displace in the direction of the axis L, but rotates around the axis on the spot. As the spindle 71 rotates, the female screw member 72 is screwed at the screwed portion of the male screw portion 77 and the first female screw portion 81, and moves to the upper side L1 as shown in FIG. 2. At this time, as described above, while the rotation around the axis L is restricted by the guide surface 37 of the guide portion 32, the female screw member 72 slides the guided surface 78a against the guide surface 37 and is displaced toward the upper side L1 along the axis L while being guided.

[0033] Due to this displacement, the valve stem screw 44 integrated with the female screw member 72 and the support member 45 fixed to the valve stem screw 44 are displaced to the upper side L1. In accordance with this displacement, the center of the first diaphragm 20 sandwiched between the lower tube portion 80 and the cover holder 52 is deformed to the upper side L1. In addition, the center of the second diaphragm 39 sandwiched between the support member 45 and the boss portion 43 is deformed to the upper side L1. At this time, the support protrusion 45a of the support member 45 is displaced to the upper side L1, and the valve body 50 is pulled up to the upper side L1. As a result, the valve body 50 is lifted from the valve seat portion 18, and the valve port 17 is opened. Due to this opening, the fluid flows inside the main body 11 through the valve port 17. At this time, one of the first port 12 and the second port 13 functions as an inlet for the fluid, and the other of the first port 12 and the second port 13 functions as an outlet for the fluid.

[0034] According to the above-mentioned embodiment, the first diaphragm 20 (sealing member) provided between the valve body 10 and the female screw member 72 (second screw feed member) maintains the airtightness inside the valve body 10, thereby preventing fluid leakage into unintended parts of the valve device 1, and improving the reliability of the airtightness of the valve device 1. When the valve body 50 is driven, the female screw member 72 is displaced in the direction of the axis L, which is the displacement direction of the valve body 50, by the rotation of the spindle 71 (first screw feed member). However, since the rotation of the female screw member 72 around the axis L is restricted, the rotational force of the drive unit 60 is not transmitted to the first diaphragm 20. Therefore, it is possible to prevent the occurrence of sliding resistance around the axis between the first diaphragm 20 and the valve body 10. Therefore, it is possible to suppress the load in the rotational direction from being applied to the spindle 71 and the female screw member 72, and improve the operability of the valve body 50. Moreover, since the first diaphragm 20 does not slide around the axis relative to the valve body 10, wear of the first diaphragm 20 can be suppressed. Furthermore, since the first diaphragm 20 deforms in the axial direction L in accordance with the displacement of the female screw member 72, the displacement of the female screw member 72 can be absorbed by the deformation of the first diaphragm 20. Therefore, it is not necessary to slide the first diaphragm 20 in the axial direction L relative to the valve body 10, and wear of the first diaphragm 20 can be suppressed. By suppressing wear of the first diaphragm 20 in this manner, the durability of the valve device 1 can be improved. Therefore, it is possible to provide a valve device 1 that can improve operability, durability, and airtightness.

[0035] Furthermore, according to this embodiment, the female screw member 72 can be slid along the guide member 29 and guided in the direction of the axis L, so that tilt and rattling of the female screw member 72 relative to the direction of the axis L can be suppressed, and the drive of the valve body 50 can be stabilized.

[0036] Moreover, according to this embodiment, the guided surface 78a of the female screw member 72 is caused to slide on the guide surface 37 of the guide member 29, so that the displacement of the female screw member 72 in the direction of the axis L can be reliably guided. Therefore, the driving of the valve body 50 can be further stabilized. Furthermore, according to this configuration, the guided surface 78a comes into contact with the guide surface 37, so that the rotation of the female screw member 72 around the axis L can be restricted by the guide surface 37. Therefore, it is possible to prevent the occurrence of sliding resistance around the axis between the first diaphragm 20 and the valve body 10, and it is possible to suppress the application of a load in the rotational direction to the spindle 71 and the female screw member 72. Furthermore, since the first diaphragm 20 does not slide around the axis relative to the valve body 10, it is possible to suppress wear of the first diaphragm 20 due to the sliding.

[0037] According to the present embodiment, the displacement of the female screw member 72 in the direction of the axis L can be guided at least at two points by sliding the at least two or more guided surfaces 78a on each of the at least two or more guided surfaces 78a. This makes it possible to further stabilize the drive of the valve body 50. Furthermore, the abutment of the guided surfaces 78a and the guide surfaces 37 can restrict the rotation of the female screw member 72 around the axis L at at least two points, so that the above-mentioned sliding of the first diaphragm 20 around the axis relative to the valve body 10 can be reliably prevented, and the application of a load in the rotational direction to the spindle 71 and the female screw member 72 can be reliably suppressed. Furthermore, wear of the first diaphragm 20 due to the sliding can be reliably suppressed.

[0038] Next, a first modified example of the first embodiment will be described. FIG. 4 is a cross-sectional view showing a valve-closed state of the valve device 1 according to the first modified example of the first embodiment. FIG. 5 is a cross-sectional view showing a valve-open state of the valve device 1 shown in FIG. 4. FIG. 6 is a cross-sectional view taken along the line BB in FIG. 4. The valve device 1 according to the first modified example includes a female screw member 90. The female screw member 90 corresponds to the female screw member 72 in the first embodiment. The female screw member 90 includes a first female screw member 91 constituting an upper part, a second female screw member 92 constituting a lower part, and a connecting member 93 connecting the first female screw member 91 and the second female screw member 92. That is, while the above-mentioned female screw member 72 is composed of one part, the female screw member 90 is composed of multiple parts. The first female screw member 91 is formed into a cylindrical shape extending in the axial direction L using a resin material, and is disposed between a pair of guide parts 32. A first female thread portion 94 is formed on the inner circumferential surface of the first female thread member 91, and the first female thread portion 94 is screwed into the male thread portion 77 of the spindle 71. A first flange portion 95 is formed on the lower end portion of the first female thread member 91, protruding radially outward.

[0039] The second female thread member 92 is formed in a cylindrical shape extending in the direction of the axis L using a metal or resin material. A second flange portion 96 protruding radially outward is formed at the upper end of the second female thread member 92. The second flange portion 96 is formed with a larger diameter than the first flange portion 95, and its upper surface abuts against the lower surface of the first flange portion 95. The connecting member 93 covers the side surface of the first flange portion 95 and a portion of the upper surface of the second flange portion 96 that is not abutted by the first flange portion 95, and connects the first female thread member 91 and the second female thread member 92 by fixing the first flange portion 95 and the second flange portion 96.

[0040] According to this configuration, at least the first female thread member 91 of the female thread member 90 can be made of resin, which can improve the slidability between the male thread portion 77 and the first female thread portion 94 and suppress wear of the first female thread portion 94. Furthermore, since the first female thread member 91 and the second female thread member 92 are configured as separate bodies, the first female thread member 91 and the spindle 71 can be screwed together separately from the second female thread member 92 and the valve stem screw 44. Therefore, there is no need to axially align the spindle 71 and the valve stem screw 44, and there is no need to worry about axial misalignment, which can facilitate assembly of the valve device 1.

[0041] Next, a second modified example of the first embodiment will be described. FIG. 7 is a cross-sectional view showing a valve-closed state of the valve device 1 according to the second modified example of the first embodiment. FIG. 8 is a cross-sectional view showing a valve-open state of the valve device 1 shown in FIG. 7. As shown in FIG. 7, the valve device 1 according to the second modified example includes a guide member 100 and a screw feed mechanism 110. The guide member 100 corresponds to the guide member 29 of the first embodiment, and the screw feed mechanism 110 corresponds to the screw feed mechanism 70 of the first embodiment. The guide member 100 includes a cylindrical guide portion 102 extending from the center of a top wall 101 facing the first diaphragm 20 in the axial direction L to the lower side L2. A first female screw portion 103 is formed on the inner peripheral surface of the guide portion 102.

[0042] The screw feed mechanism 110 includes a spindle 111 extending in the direction of the axis L, and a second screw feed member 112 connected to the lower end of the spindle 111. An upper end 113 of the spindle 111 is connected to the drive unit 60, thereby allowing the spindle 111 to rotate around the axis L. A large diameter portion 114 having a diameter larger than other portions of the spindle 111 is formed at the lower end of the spindle 111. Bearings 117, which will be described later, are disposed on an upper side L1 and a lower side L2 of the large diameter portion 114. A male thread portion 115 is formed on the outer circumferential surface of the central portion of the spindle 111 in the direction of the axis L, and the male thread portion 115 is screwed into the first female thread portion 103. In the second modified example, the spindle 111 is not restricted in its displacement in the direction of the axis L, and when the spindle 111 is rotated by the drive unit 60, the spindle 111 moves in the direction of the axis L while rotating around the axis L by being screwed at the threaded portion between the male thread portion 115 and the first female thread portion 103.

[0043] The second screw feed member 112 includes a lower cylinder portion 116 constituting the lower side L2 portion, a bearing 117 that suppresses the rotational force of the spindle 111 from being transmitted to the lower cylinder portion 116, and a cover 118 that accommodates the bearing 117. The lower cylinder portion 116 corresponds to the second female screw member 92 of the first modified example described above. A second female screw portion 119 that screws into the valve stem male screw portion 46 formed on the outer circumferential surface of the valve stem screw 44 is formed on the inner circumferential surface of the lower cylinder portion 116. A flange portion 120 that protrudes radially outward is formed on the upper end of the lower cylinder portion 116. One bearing 117 is disposed between the flange portion 120 of the lower cylinder portion 116 and the large diameter portion 114 of the spindle 111. Also, one bearing 117 is disposed between the large diameter portion 114 of the spindle 111 and the cover 118. As a result, the large diameter portion 114 of the spindle 111 is sandwiched between the two bearings 117 in the direction of the axis L. The rolling elements of the upper bearing 117 on the upper side L1 abut against the upper surface of the large diameter portion 114, and the rolling elements of the lower bearing 117 on the lower side L2 abut against the lower surface of the large diameter portion 114, so that the rotational force of the spindle 111 is transmitted to the bearings 117 but is not transmitted to the second screw feed member 112. The cover 118 covers the upper surface of the upper bearing 117 on the upper side L1, the side surfaces of the upper and lower bearings 117, the side surface of the large diameter portion 114, and the side surface of the flange portion 120.

[0044] In the second modified example, the valve device 1 is changed from the valve closed state shown in FIG. 7 to the valve open state shown in FIG. 8 by driving the drive unit 60. At this time, the rotational force of the drive unit 60 is transmitted to the spindle 111, and the spindle 111 rotates around the axis L as described above, and the male screw portion 115 is screwed and displaced to the upper side L1. Then, this displacement is transmitted to the second screw feed member 112 via the large diameter portion 114, the bearing 117, and the cover 118, and the second screw feed member 112 is displaced to the upper side L1. However, since the rotational force of the spindle 111 is transmitted to the bearing 117 but not to the second screw feed member 112, the second screw feed member 112 is displaced to the upper side L1 in a state in which the rotation around the axis L is restricted. As in the first embodiment and the first modified example, as the second screw feed member 112 is displaced toward the upper side L1, the first diaphragm 20 and the second diaphragm 39 are displaced toward the upper side L1, and the valve body 50 is displaced toward the upper side L1. According to this configuration, the present invention can be configured using the valve device 1 configured to displace the spindle 111 in the axial L direction.

[0045] Next, a second embodiment of the present invention will be described. FIG. 9 is a cross-sectional view showing a valve-closed state of the valve device 200 according to the second embodiment. FIG. 10 is a cross-sectional view showing a valve-open state of the valve device 200 shown in FIG. 9. FIG. 11 is a cross-sectional view taken along the arrow CC in FIG. 9. As shown in FIG. 9, the valve device 200 includes a valve body 210 having a valve port 217 through which a fluid passes, a valve element 280 that approaches or moves away from the valve port 217 in the axial L direction (displacement direction) inside the valve body 210, a drive unit 260 that drives the valve element 280, a screw feed mechanism 270 that transmits the drive force of the drive unit 260 to the valve element 280, and a bellows 290 (sealing member). The valve body 210 includes a cylindrical main body 211 that extends in the intersecting direction X. A first port 212 that opens in the intersecting direction X is formed at the end of the left side X1 of the main body 211. A second port 213 that opens in the intersecting direction X is formed at the end of the main body 211 on the right side X2.

[0046] A partition wall 214 is disposed inside the main body 211, extending along the axis A of the main body 211 and dividing the inside of the main body 211 into upper and lower parts. The partition wall 214 is supported in the cross direction X inside the main body 11 by a left vertical wall 215 extending from its left side X1 end to the inner wall of the lower side L2 of the main body 11 and a right vertical wall 216 extending from its right side X2 end to the inner wall of the upper side L1 of the main body 11. A valve port 217 penetrating in the axial direction L is formed in the center of the partition wall 214, and the upper edge of the valve port 217 constitutes a valve seat portion 218. A cylindrical support portion 219 opening to the upper side L1 is formed on the wall surface of the upper side L1 of the main body 211. A step portion 220 recessed to the lower side L2 is formed on the inner peripheral surface of the upper end of the support portion 219, and a guide member 230 described later is fitted into the step portion 220. A first support protrusion 221 protruding toward the upper side L1 is formed on the upper surface of the support portion 219. In addition, a first male screw portion 222 is formed on the outer circumferential surface of the upper end portion of the support portion 219.

[0047] The guide member 230 is formed in a bottomed cylindrical shape that opens to the upper side L1, and a through hole 231 that penetrates in the axis L direction is formed in the bottom surface. A lower side L2 portion of the female screw member 272 described later is inserted into the through hole 231. As shown in FIG. 11, the inner peripheral surface of the through hole 231 is formed in a substantially circular shape when viewed from the axis L direction, and a guide surface 232 that is parallel to the axis L direction is formed in a part of the through hole 231. Specifically, the guide surface 232 is formed by the inner surfaces of each of four V-grooves formed in the inner surface of the through hole 231 so as to fit the four corners of the lower side L2 portion of the female screw member 272 formed in a rectangular parallelepiped shape. A flange-shaped supported portion 233 that protrudes radially outward is formed in the upper portion of the guide member 230. The first support protrusion 221 of the support portion 219 described above is fixed to the lower surface of the supported portion 233 via a packing P. For this fixing, a method such as welding, soldering, or brazing can be used. A first receiving portion 234 is formed on the upper end surface of the guide member 230, protruding to the upper side L1 along the edge of the through hole 231. A lower end portion of a bellows 290 (sealing member) described later is fixed to the upper surface of the first receiving portion 234.

[0048] A cover 240 is installed on the upper side L1 of the guide member 230. The cover 240 includes a top wall 241 and a side wall 242 extending from the outer edge of the top wall 241 to the lower side L2. The top wall 241 corresponds to the top wall 30 in the guide member 29 of the first embodiment described above, and therefore detailed description thereof will be omitted or simplified here. However, the top wall 241 supports a spindle 271 described later so as to be rotatable around the axis L, and regulates the displacement of the spindle 271 in the direction of the axis L. A second support protrusion 243 protruding to the lower side L2 is formed on the lower end surface of the side wall 242, and the second support protrusion 243 is fixed to the upper end surface of the supported portion 233 of the guide member 230 via a packing P. For this fixing, a method such as welding, soldering, or brazing can be used. The support part 219 and the cover 240 thus configured are circumferentially covered and fixed to each other by a nut member 250 that screws into the first male threaded part 222 of the support part 219. This fixation makes the support part 219 (valve body 210), the guide member 230, and the cover 240 integral with each other.

[0049] The screw feed mechanism 70 includes a spindle 271 (first screw feed member) and a female screw member 272 (second screw feed member). A second male screw portion 273 is formed on the outer peripheral surface of the spindle 271. The female screw member 272 is formed in a columnar shape extending in the axial direction L. A guide hole 274 that opens to the upper side L1 is formed in the center of the female screw member 272, and a second female screw portion 275 that screws into the second male screw portion 273 is formed on the inner surface of the guide hole 274. A flange-shaped second receiving portion 276 that protrudes radially outward is formed on the upper end of the female screw member 272. The upper end of a bellows 290 is fixed to the lower surface of the second receiving portion 276. The lower L2 portion of the female screw member 272 is formed in a rectangular parallelepiped shape as described above, and among its outer surfaces, the outer surfaces forming the four corners constitute guided surfaces 278 that slide against the guide surface 232, as shown in Figure 11.

[0050] The bellows 290 is formed by, for example, pressing a metal plate material into a bellows shape, forming it into a cylindrical shape extending in the axial direction L, and being deformable so as to expand and contract in the axial direction L. The bellows 290 is disposed at a position covering the outer periphery of the female screw member 272 in the circumferential direction, and its upper end is fixed to the lower surface (second screw feed member) of the second receiving portion 276, and its lower end is fixed to the upper surface (guide member 230 integral with the valve body 210) of the first receiving portion 234. That is, the bellows 290 is provided across the valve body 210 and the second screw feed member. The bellows 290 can be fixed by welding, soldering, brazing, or other methods. The bellows 290 is installed to separate a space formed by the inside of the main body 211 and the inside of the guide member 230, and a space formed by the inside of the cover 240. This configuration maintains airtightness inside the valve body 210. According to this configuration, in addition to using the first diaphragm 20 as a sealing member, the valve device 200 can be configured using the bellows 290 as a sealing member.

[0051] The above describes in detail the embodiments and modified examples of the present invention with reference to the drawings. However, the specific configurations are not limited to these, and the present invention also includes design changes and the like that do not deviate from the gist of the present invention.

[0052] For example, in the first embodiment, the guide surface 37 provided on the guide member 29 and the guided surface 78a of the female screw member 72 are slid to guide the female screw member 72 in the direction of the axis L while restricting the rotation of the female screw member 72 around the axis L. However, the configuration of the rotation restriction and guide of the female screw member 72 is not limited to this, and may be configured as follows. That is, a pin is inserted into the female screw member 72 in a direction perpendicular to the axis L, and both ends of the pin are protruded in the same direction to form protrusions. Then, a groove portion into which the protrusion of the pin fits is formed on the inner peripheral surface of the guide member 29 by extending in the direction of the axis L. Then, the protrusion of the pin is slid on the inner wall surface of the groove portion to guide the female screw member 72 in the direction of the axis L while restricting the rotation of the female screw member 72 around the axis L. Even with such a configuration, it is possible to suppress the rotational force of the drive unit 60 from being transmitted to the first diaphragm 20. The above-mentioned protrusion does not necessarily have to be a pin, and may be formed using any other structure. Also, the protrusion may be provided on the guide member 29 side, and the groove may be provided on the female screw member 72 side. [Explanation of symbols]

[0053] L axis 1 Valve gear 17 Valve port 10 Valve body 20 First diaphragm (sealing member) 50 Valve body 60 Drive unit 70 Screw feed mechanism 71 Spindle (first screw feed member) 72 Female thread member (second screw feed member)

Claims

1. A valve device comprising: a valve body having a valve port; a valve element that moves toward or away from the valve port inside the valve body; a drive unit that drives the valve element; a screw feed mechanism that transmits a drive force of the drive unit to the valve element; and a sealing member that maintains airtightness inside the valve body, The screw feed mechanism includes a first screw feed member that rotates around an axis by the driving force, and a second screw feed member that is connected to the first screw feed member and is connected to the valve body, the second screw feed member is displaced in the displacement direction of the valve body by the rotation of the first screw feed member in a state in which the rotation about the axis is restricted, The valve device, characterized in that the sealing member is provided across the valve body and the second screw feed member, and deforms in the displacement direction in accordance with the displacement of the second screw feed member.

2. 2. The valve device according to claim 1, wherein the valve body is provided with a guide member along which the second screw feed member slides in the displacement direction.

3. The guide member is provided with a guide surface parallel to the displacement direction, 3. The valve device according to claim 2, wherein the second screw feed member is provided with a guided surface that slides on the guide surface.

4. 4. The valve device according to claim 3, wherein at least two of the guide surfaces and at least two of the guided surfaces are provided.

5. 2. The valve assembly of claim 1, wherein the sealing member is a diaphragm.

6. 2. The valve assembly according to claim 1, wherein the sealing member is a bellows.

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