VALVE DEVICE

Abstract

[Task] The purpose is to provide a valve device that can achieve an improvement in functionality, durability and airtightness. [Solution] A valve device 1 comprises a valve body 10, which includes a valve port 17, a valve element 50, which is positioned close to or spaced away from the valve port 17, an actuating section 60 for actuating the valve element 50, a screw feed unit 70 for transmitting an actuating force from the actuating section 60 to the valve element 50, and a first diaphragm 20 for maintaining an airtight seal of the interior of the valve body 10. The screw feed unit 70 comprises a spindle 71, which rotates about the axis, and an internally threaded element 72, which is connected to the spindle 71 and to the valve element 50. The internally threaded element 72 is displaced by the rotation of the spindle 71 in a displacement direction of the valve element 50, while the rotation about the axis is limited.The first membrane 20 is provided over the valve body 10 and the internal thread element 72 and deforms according to the displacement of the internal thread element 72 in the direction of displacement.

Description

[Technical field]

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

[0002] A valve device for controlling the flow rate of a fluid flowing to 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 element that increases or decreases an effective opening area of ​​the valve port. In the valve device, the valve element is coaxially integrated with a valve stem member inserted into the valve port. A part of the valve stem member is located in a guide hole extending in an axial direction of a tubular member fixed to the housing. A male thread portion is formed on the outer peripheral surface of the valve stem member. The male thread portion is screwed to an female thread portion formed on the inner peripheral surface of the guide hole.An O-ring is mounted on the outer peripheral surface of the valve stem element to ensure airtightness between the portion where the male thread is not formed and the inner peripheral surface of the guide hole. The O-ring prevents fluid from entering the guide hole. The valve stem element moves in the axial direction while being rotated around the axis by a stepper motor, and according to this movement, the valve element moves in the axial direction. [Citation list][Patent document]

[0003] [Patent Document 1] Patent Publication No. JP 2006-266403 [Overview of the invention][Technical problem]

[0004] However, with the valve device described above, when the valve stem member rotates around the axis and moves in the axial direction, the outer peripheral surface of the O-ring slides around the axis and in the axial direction on the inner peripheral surface of the guide hole, thereby reducing the performance of the valve stem member due to sliding resistance. Furthermore, this sliding causes wear of the O-ring, thus tending to reduce the durability of the valve stem member. Due to this wear, a gap is formed between the outer peripheral surface of the O-ring and the inner peripheral surface of the guide hole, and fluid inflow into the guide hole through the gap tends to reduce the airtightness reliability of the valve device.

[0005] The purpose of the present invention is to provide a valve device that can achieve improvement in operability, durability and airtightness. [Means of solving the problem]

[0006] To solve the problem and achieve the purpose, a valve device of the present invention is a valve device comprising a valve body comprising a valve port, a valve element which approaches or is spaced apart from the valve port in an interior of the valve body, a drive section for driving the valve element, a screw feed unit for transmitting a driving force of the drive section to the valve element, and a sealing element for maintaining airtightness of the interior of the valve body, characterized in that the screw feed unit comprises a first screw feed element which rotates about the axis by the driving force, and a second screw feed element which is connected to the first screw feed element and is connected to the valve element,that the second screw feed element is displaced by the rotation of the first screw feed element in a displacement direction of the valve element, while rotation about the axis is limited, and that the sealing element is provided over the valve body and the second screw feed element and deforms according to the displacement of the second screw feed element in the displacement direction.,

[0007] According to the present invention, the sealing member provided across the valve body and the second screw feed member maintains the airtightness of the interior of the valve body, thereby preventing fluid leakage caused by fluid entering an unintended portion of the valve device and improving the reliability of the airtightness of the valve device. When driving the valve element, the rotation of the first screw feed member causes the second screw feed member to slide in the displacement direction of the valve element. At this time, the rotation of the second screw feed member around the axis is limited; therefore, the rotational force of the driving portion is not transmitted to the sealing member. This prevents the generation of sliding resistance around the axis between the sealing member and the valve body.Thus, the load in a rotational direction can be suppressed from being exerted on the first screw feed member and the second screw feed member, resulting in improved performance of the valve element. Furthermore, since the seal member does not slide on the valve body around the axis, wear of the seal member can be suppressed. Furthermore, since the seal member deforms according to the displacement of the second screw feed member in the displacement direction of the valve element, the displacement of the second screw feed member can be absorbed by the deformation of the seal member. Therefore, it is not necessary for the seal member to slide on the valve body in the displacement direction, so wear of the seal member can be suppressed. In this way, wear of the seal member is suppressed, resulting in improved durability of the valve device.Thus, the valve device which can achieve improvement in operability, durability and airtightness can be provided.

[0008] It is preferred that a guide element is provided on the valve body, which causes the second screw feed element to slide in the displacement direction. According to this structure, the second screw feed element can slide on the guide element and be guided in the displacement direction; therefore, tilt of the second screw feed element with respect to the displacement direction and rattling can be suppressed, resulting in the stabilization of the drive of the valve element.

[0009] Furthermore, it is preferable that guiding surfaces parallel to the displacement direction are provided on the guide element, and that guided surfaces sliding on the guiding surfaces are provided on the second screw feed element. According to this structure, the guidance of the displacement of the second screw feed element in the displacement direction can be ensured by the guided surfaces of the second screw feed element sliding on the guiding surfaces of the guide element. Therefore, the drive of the valve element can be further stabilized. Furthermore, according to this structure, the guided surfaces abut against the respective guiding surfaces, so that the rotation of the second screw feed element about the axis can be limited by the guiding surfaces.This prevents the generation of sliding resistance around the axis between the seal element and the valve body, and suppresses the rotational load exerted on the first screw feed element and the second screw feed element. Furthermore, since the seal element does not slide around the axis on the valve body, wear of the seal element caused by sliding can be suppressed.

[0010] The guiding surfaces and the guided surfaces are characterized in that at least two or more guiding surfaces and at least two or more guided surfaces are provided. According to this structure, the guidance of the displacement of the second screw feed member in the displacement direction can be performed at least at two locations by the sliding of the at least two or more guiding surfaces provided on the at least two or more respective guided surfaces provided. Therefore, the drive of the valve element can be further stabilized. Furthermore, the abutment of the guided surfaces on the respective guiding surfaces means that the rotation of the second screw feed member about the axis can be restricted at least at two locations.This reliably prevents the above-described sliding of the sealing element on the valve body around the axis, and reliably suppresses the load exerted in the rotational direction on the first screw feed element and the second screw feed element. Furthermore, wear of the sealing element caused by sliding can be reliably suppressed.

[0011] The sealing element may be a diaphragm. According to this structure, the valve device of the present invention can be formed using the diaphragm as the sealing element.

[0012] The sealing element may be a bellows. According to this structure, the valve device of the present invention can be formed using the bellows as the sealing element. [Effects of the invention]

[0013] According to the present invention, the valve device which can achieve improvement in operability, durability and airtightness can be provided. [Brief explanation of the figures] Fig. 1 is a cross-sectional view showing a valve closing state of a valve device according to a first embodiment of the present invention; Fig. 2 is a cross-sectional view showing a valve opening state of the Fig. 1; Fig. 3 is a cross-sectional view along line AA of Fig. 1; Fig. 4 is a cross-sectional view showing a valve closing state of a valve device according to a first modification of the first embodiment; Fig. 5 is a cross-sectional view showing a valve opening state of the Fig. 4 shows the valve device shown; Fig. 6 is a cross-sectional view along line BB of Fig. 4; Fig. 7 is a cross-sectional view showing a valve closing state of a valve device according to a second modification of the first embodiment; Fig. 8 is a cross-sectional view showing a valve opening state of the Fig. 7 shows the valve device shown; Fig. 9 is a cross-sectional view showing a valve closing state of a valve device according to a second embodiment; Fig. 10 is a cross-sectional view showing a valve opening state of the Fig. 9 shows the valve device; and Fig. 11 is a cross-sectional view along the line CC of Fig. 9. [Forms for carrying out the invention]

[0014] In the following, a valve device 1 according to a first embodiment of the present invention based on Fig. 1 to Fig. 3. The valve device 1 is a device arranged in a part of a pipeline through which a fluid such as a liquid or a gas flows. The valve device 1 is used to control the flow rate of a fluid. In the following explanation, a direction along an axial line L of a spindle 71 (a first screw feeding member) and a female thread member 72 (a second screw feeding member), which will be described later, is referred to as the "axial line L direction." One side of the axial line L direction is referred to as the "top side L1," and the other side is referred to as the "bottom side L2." A direction crossing the axial line L direction is referred to as the "crossing direction X." One side of the crossing direction X is referred to as the "left side X1," and the other side is referred to as the "right side X2."These terms are for convenience only and do not necessarily correspond to the directions of the valve device 1 in its actual use state, etc., and these terms are not intended to limit any direction of the valve device 1.

[0015] The valve device 1 comprises, as in Fig. 1, a valve body 10 comprising a valve port 17 through which a fluid flows, a valve element 50 which, inside the valve body 10, approaches or is spaced from the valve port 17 in the direction of the axial line L (a displacement direction), a drive portion 60 for driving the valve element 50, and a screw feed unit 70 for transmitting a driving force of the drive portion 60 to the valve element 50. The valve body 10 comprises a tubular body 11 extending in the crossing direction X. At the end portion of the body 11 located on the left side X1, a first port 12 is formed which opens in the crossing direction X. At the end portion of the body 11 located on the right side X2, a second port 13 is formed which opens in the crossing direction X.A partition wall 14 is arranged inside the body 11, extending along an axial line A of the body 11 and separating the interior of the body 11 into the upper part and the lower part. The partition wall 14 is supported by a left vertical wall 15 extending from the end portion of the partition wall 14 located on the left side X1 to the inner wall of the body 11 located on the upper side L1, and a right vertical wall 16 extending from the end portion of the partition wall 14 located on the right side X2 to the inner wall of the body 11 located on the lower side L2, such that the partition wall 14 extends inside the body 11 in the crossing direction X. The valve port 17 is formed in the center of the partition wall 14 and passes through in the direction of the axial line L.A valve seat portion 18 is formed on the edge portion of the valve connection 17 located in the upper side L1, which valve seat portion 18 projects over the entire circumference of the valve connection 17 in the direction of the upper side L1.

[0016] A first diaphragm 20 (a sealing member) is mounted on the wall surface of the body 11 located in the upper side L1, sealing an upper through-hole 19 extending in the direction of the axial line L. The first diaphragm 20 is formed in a plate shape by a resinous member elastically deformable in the direction of the axial line L, and seals the upper through-hole 19 of the body 11 to maintain airtightness of the interior of the body 11 (the valve body 10). The lower surface of the outer peripheral side of the first diaphragm 20 abuts against the wall surface of the body 11 located in the upper side L1. The upper surface of the central portion of the first diaphragm 20 abuts against the lower surface of a lower cylindrical portion 80 of the internally threaded member 72 described later. That is, the first diaphragm 20 is provided across the valve body 10 and the internally threaded member 72.

[0017] A first holding portion 21 for securing the first diaphragm 20 to the body 11 is mounted on the upper surface L1 of the first diaphragm 20. The first holding portion 21 is tubular and opens toward the upper surface L1. A first protrusion 23 is formed on a bottom surface 22 of the first holding portion 21 and protrudes toward the lower surface L2. The bottom surface 22 holds the upper surface of the first diaphragm 20 down toward the lower surface L2, while the first protrusion 23 digs into the upper surface of the first diaphragm 20, thereby securing the first diaphragm 20 to the body 11. An inclined surface 24 is formed at the center portion of the first holding portion 21, which is inclined toward the center toward the upper surface L1. The formation of the inclined surface 24 creates a gap in the direction of the axial line L between the first holding portion 21 and the center portion of the first diaphragm 20.The gap serves as a deformation clearance to the upper side L1 of the first diaphragm 20. In the center of the first holding portion 21, a through hole 25 is formed, which passes through in the direction of the axial line L.

[0018] A sleeve 26 is mounted on the edge portion of the through-hole 25, supporting the lower cylindrical portion 80 of the female thread member 72. The sleeve 26 is formed in a circular ring shape and extends in the direction of the axial line L. The lower cylindrical portion 80 of the female thread member 72 is inserted into the inside of the sleeve 26. A recessed portion 27 is formed on the outer peripheral surface of the sleeve 26 and is recessed diametrically inward. The recessed portion 27 is a portion that engages with the edge portion of the through-hole 25. An annular retaining spring 28 is arranged on the inner surface of the recessed portion 27 over the entire circumference. The lower end portion of the retaining spring 28 abuts against the upper edge portion of the through-hole 25 engaging in the recessed portion 27 and holds the upper edge portion against the inner surface of the recessed portion 27.Thus, the sleeve 26 is fixed to the first holding portion 21. A guide member 29 is mounted on the upper surface L1 of the first holding portion 21, supporting the screw feed unit 70. The guide member 29 includes a top wall 30 facing the first diaphragm 20 in the direction of the axial line L, a side wall 31 extending from the outer edge of the top wall 30 toward the bottom surface L2 and abutting the upper surface of the first holding portion 21, and a pair of guide portions 32 extending from the center portion of the top wall 30 toward the bottom surface L2.

[0019] A plate-shaped bracket 33 is arranged on the upper surface of the ceiling wall 30. A first stop screw 34 is fixed to the bracket 33, extending in the direction of the axial line L and inserted into the bracket 33, the ceiling wall 30, the first holding portion 21, and the first diaphragm 20. The first stop screw 34 fixes the guide member 29 to the body 11. A first through-hole 35, which passes through in the direction of the axial line L, and a second through-hole 36, which is continuous with the first through-hole 35 toward the bottom surface L2, are formed in the center of the ceiling wall 30. The first through-hole 35 opens onto the upper surface of the ceiling wall 30. The second through-hole 36 is formed to have a smaller diameter than the first through-hole 35.The second through-hole 36 communicates with the first through-hole 35 and also with a space between the pair of guide portions 32. The side wall 31 extends in the direction of the axial line L between the ceiling wall 30 and the first support portion 21. The side wall 31 may be tubular, with the side wall 31 enclosing the outer edge of the ceiling wall 30 around the axis of the axial line L, or may be columnar, with the side wall 31 depending from a part of the ceiling wall 30.

[0020] As in Fig. 3, the two guide portions 32 (the pair of guide portions 32) are formed so as to be spaced apart from each other in the crossing direction X. On the inner side of each of the guide portions 32 in the crossing direction X, a guide surface 37 is formed which slides on a guided surface 78a of the female thread member 72. The guide surfaces 37 extend parallel to the direction of the axial line L. In the present embodiment, the guide surfaces 37 are formed in the portion inward in the crossing direction X from the pair of guide portions 32; however, for example, the guide portion 32 may be tubular, and a part of the inner peripheral surface may be a surface parallel to the direction of the axial line L to form the guide surface 37.A second diaphragm 39 is mounted on the wall surface of the body 11 located at the bottom L2, sealing a lower through-hole 38 extending in the direction of the axial line L. The second diaphragm 39 is formed into a plate shape by a resinous member elastically deformable in the direction of the axial line L, and seals the lower through-hole 38 of the body 11 to maintain the airtightness of the interior of the body 11 (the valve body 10). The upper surface of the outer edge side of the second diaphragm 39 abuts against the wall surface of the body 11 located at the bottom L2.

[0021] The upper surface of the central portion of the second diaphragm 39 bears against the lower end surface of a support member 45 described later. A second holding portion 40 for fixing the second diaphragm 39 to the body 11 is mounted on the lower surface L2 of the second diaphragm 39. The second holding portion 40 is tubular in shape and opens toward the lower surface L2. A second projection 42 is formed on an upper surface 41 of the second holding portion 40 and projects toward the upper surface L1. The upper surface 41 presses down the lower surface of the second diaphragm 39 toward the upper surface L1, while the second projection 42 digs into the lower surface of the second diaphragm 39, thereby fixing the second diaphragm 39 to the body 11.

[0022] A tubular boss portion 43 is formed at the central portion of the second holding portion 40. The upper surface of the boss portion 43 abuts the lower surface of the second diaphragm 39. A valve rod bolt 44 is fixed to the central portion of the boss portion 43 and inserted into the boss portion 43, the valve element 50, and the first diaphragm 20 in the direction of the axial line L. The tubular support member 45, which supports the valve element 50, is fixed to the outer peripheral surface of the valve rod bolt 44. A support projection 45a is formed on the outer peripheral surface of the support member 45 and projects outward in the crossing direction X. The upper surface of the support projection 45a abuts the lower surface of the valve element 50. The lower end surface of the support member 45 abuts the upper surface of the second diaphragm 39.As a result, the second membrane 39 is held clamped in the direction of the axial line L between the above-described hump portion 43 and support element 45.

[0023] A valve rod male threaded portion 46 is formed on the outer peripheral surface of the end portion of the valve rod screw 44 located in the upper surface L1. The valve rod male threaded portion 46 is screwed to a second female threaded portion 82 formed on the inner peripheral surface of the lower cylindrical portion 80 of the female thread member 72. A cap 47 is mounted on the lower surface L2 of the second holding portion 40, covering the boss portion 43 and the valve rod screw 44. The cap 47 is box-shaped and opens toward the upper surface L1. A flange 48 is formed at the edge portion of the opening of the cap 47, projecting outward in the crossing direction X. A second stopper screw 49 is fixed to the flange 48 and inserted into the flange 48, the second holding portion 40, and the second diaphragm 39 in the direction of the axial line L.

[0024] The valve element 50 is a member that approaches or is spaced apart from the valve port 17 inside the valve body 10, for example, to open or close the valve port 17. The valve element 50 is formed in the shape of a thick plate, circumferentially covering the outer peripheral surface of the above-described support member 45. As described above, the upper surface of the support projection 45a abuts against the lower surface of the valve element 50. On the other hand, a plate-shaped valve cover 51 is arranged on the upper surface of the valve element 50. Between the upper surface of the valve cover 51 and the lower surface of the first diaphragm 20, a tubular cover holder 52 is arranged, extending in the direction of the axial line L.As a result, the valve element 50 is held clamped in the direction of the axial line L between the support projection 45a arranged in the lower surface L2 and the valve cover 51 and the cover holder 52 arranged in the upper surface L1. An O-ring 53 is arranged on the upper surface of the valve cover 51, forming a seal between the inner peripheral surface of the cover holder 52 and the outer peripheral surface of the support element 45. The drive section 60 is a section that applies a rotational force, which is a driving force, to the screw feed unit 70. The drive section 60 includes, for example, a stepping motor, etc.

[0025] The screw feed unit 70 is a unit that transmits the driving force of the drive section 60 to the valve element 50. The screw feed unit 70 includes the spindle 71 (the first screw feed element) and the internally threaded member 72 (the second screw feed element), each made of a metallic material and extending in the direction of the axial line L. An upper end portion 73 of the spindle 71 is connected to the drive section 60. This enables the spindle 71 to rotate about the axis of the axial line L. A large-diameter portion 74 is formed on the bottom surface L2 of the upper end portion 73, which has a larger diameter than other parts of the spindle 71. The large-diameter portion 74 is located within the first through-hole 35 of the above-described guide member 29.

[0026] Annular thrust washers 75 are arranged on the upper surface and the lower surface of the large-diameter portion 74. The thrust washer 75 located in the upper surface L1 abuts against the above-described bracket 33, with displacement toward the upper surface L1 being limited. The thrust washer 75 located in the lower surface L2 abuts against a stepped portion 76 formed between the first through-hole 35 and the second through-hole 36, with displacement toward the lower surface L2 being limited. This structure enables the spindle 71 to rotate about the axis of the axial line L while limiting displacement in the direction of the axial line L. An external thread portion 77 is formed on the outer peripheral surface of the portion of the spindle 71 located in the lower surface L2.The external thread section 77 is a screw which is screwed to a first internal thread section 81 of the internal thread element 72.

[0027] The internal thread element 72 is provided coaxially with the spindle 71 and comprises an upper cylindrical portion 78 forming the portion located in the upper surface L1, a large cylindrical portion 79 continuous with the upper cylindrical portion 78 and extending toward the lower surface L2, and the lower cylindrical portion 80 continuous with the large cylindrical portion 79 and extending toward the lower surface L2. As shown in Fig. 3, the upper cylindrical portion 78 is formed in a substantially cylindrical shape and is disposed between the pair of guide portions 32 of the guide member 29. On both end surfaces of the upper cylindrical portion 78 located in the crossing direction X, the guided surfaces 78a are formed, which are opposite to the guiding surfaces 37 of the guide portions 32 in the crossing direction X. The guided surfaces 78a, like the guiding surfaces 37, extend parallel to the direction of the axial line L. The distance in the crossing direction X between the guided surface 78a located in the left side X1 and the guided surface 78a located in the right side X2 is slightly smaller than the distance in the crossing direction X between the guiding surface 37 located in the left side X1 and the guiding surface 37 located in the right side X2.This results in the guided surfaces 78a being able to slide in the direction of the axial line L on the respective guiding surfaces 37 while the upper cylindrical portion 78 is disposed between the pair of guiding portions 32.

[0028] Furthermore, according to this structure, the guided surfaces 78a abut against the respective guiding surfaces 37, so that the rotation of the upper cylindrical portion 78 (of the female thread member 72) about the axis of the axial line L is limited by the guiding surfaces 37. In order to ensure the sliding of the guided surfaces 78a on the respective guiding surfaces 37 and also to ensure the limitation of the rotation of the female thread member 72, at least two or more guiding surfaces 37 are preferably provided. Accordingly, at least two or more guided surfaces 78a are also preferably provided. On the inner peripheral surface of the upper cylindrical portion 78, the first female thread portion 81 is formed, which is screwed to the male thread portion 77.

[0029] The large cylindrical portion 79 is formed to have a larger diameter than the upper cylindrical portion 78 and the lower cylindrical portion 80. The upper end surface of the large cylindrical portion 79 can abut against the lower end surfaces of the guide portions 32. This abutment results in limiting the displacement of the internally threaded member 72 toward the upper surface L1. As described above, the lower cylindrical portion 80 is inserted into the sleeve 26. The outer peripheral surface of the lower cylindrical portion 80 can slide on the inner peripheral surface of the sleeve 26. The lower end surface of the lower cylindrical portion 80 abuts against the upper surface of the first diaphragm 20. As a result, the first diaphragm 20 is held clamped in the direction of the axial line L between the lower cylindrical portion 80 and the cover holder 52 described above.The second internal thread portion 82 is formed on the inner peripheral surface of the lower cylindrical portion 80.

[0030] The second internal thread portion 82 is screwed to the valve rod external thread portion 46 formed in the above-described valve rod screw 44. This screwing results in the integration of the internal thread element 72 with the valve rod screw 44; thus, the internal thread element 72 is connected to the valve element 50 via the support member 45 attached to the valve rod screw 44. That is, the internal thread element 72 is screwed to the external thread portion 77 of the spindle 71 and is connected to the valve element 50. Furthermore, as described above, the first diaphragm 20 is clamped between the cover holder 52 and the lower cylindrical portion 80, so that the internal thread element 72 is connected to the first diaphragm 20 via the lower cylindrical portion 80.

[0031] Next, an operation of the valve device 1 will be explained. As shown in Fig. 1, in a valve-closing state in which the valve element 50 sits on the valve seat portion 18 and the valve port 17 is closed, the flow of a fluid inside the body 11 is stopped. From this state, the drive portion 60 is driven. In particular, a predetermined pulse signal is transmitted to the stepper motor, whereby the rotational force is exerted from the drive portion 60 to the spindle 71. The rotational force causes the spindle 71 to rotate about the axis of the axial line L. Here, as described above, the displacement of the spindle 71 in the direction of the axial line L is limited, so that no displacement occurs in the direction of the axial line L, and the spindle 71 rotates thereabout. The rotation of the spindle 71 leads to screw feeding at the screwing portion of the externally threaded portion 77 and the first internally threaded portion 81, whereby the internally threaded element 72, as shown in Fig. 2, in the direction of the upper surface L1. As described above, the guided surfaces 78a slide on the respective guiding surfaces 37, while the rotation of the internal thread element 72 about the axis of the axial line L is limited by the guiding surfaces 37 of the guide sections 32, whereby the internal thread element 72 slides with the guide along the axial line L in the direction of the upper surface L1.

[0032] Due to this displacement, the valve rod screw 44 integrated with the internally threaded member 72 and the support member 45 attached to the valve rod screw 44 move toward the top surface L1. Corresponding to this displacement, the central portion of the first diaphragm 20, which is clamped between the lower cylindrical portion 80 and the cover holder 52, deforms toward the top surface L1. Furthermore, the central portion of the second diaphragm 39, which is clamped between the support member 45 and the boss portion 43, deforms toward the top surface L1. At this time, the support projection 45a of the support member 45 moves toward the top surface L1, thereby pulling the valve element 50 toward the top surface L1. As a result, the valve element 50 leaves the valve seat portion 18 to open the valve port 17. This opening causes fluid to flow into the interior of the body 11 through the valve port 17.Here, one of the first port 12 and the second port 13 serves as an inlet opening for a fluid, while the other of the first port 12 and the second port 13 serves as an outlet opening for a fluid.

[0033] According to the above-described embodiment, the first diaphragm 20 (the sealing member) provided over the valve body 10 and the internally threaded member 72 (the second screw feed member) maintains the airtightness of the interior of the valve body 10, thereby preventing fluid leakage caused by fluid entering an unintended portion of the valve device 1 and improving the reliability of the airtightness of the valve device 1. When driving the valve element 50, the rotation of the spindle 71 (the first screw feed member) causes the internally threaded member 72 to slide in the direction of the axial line L, which is the sliding direction of the valve element 50. At this time, the rotation of the internally threaded member 72 around the axis of the axial line L is limited; therefore, the rotational force of the driving portion 60 is not transmitted to the first diaphragm 20.This prevents the generation of sliding resistance around the axis between the first diaphragm 20 and the valve body 10. Thus, the load in the rotational direction can be suppressed from being exerted on the spindle 71 and the internal thread member 72, resulting in improved performance of the valve element 50. Furthermore, since the first diaphragm 20 does not slide on the valve body 10 around the axis, wear of the first diaphragm 20 can be suppressed. Furthermore, since the first diaphragm 20 deforms according to the displacement of the internal thread member 72 in the direction of the axial line L, the displacement of the internal thread member 72 can be absorbed by the deformation of the first diaphragm 20. Therefore, it is not necessary for the first diaphragm 20 to slide in the direction of the axial line L on the valve body 10, so that wear of the first diaphragm 20 can be suppressed.In this way, wear of the first diaphragm 20 is suppressed, resulting in improved durability of the valve device 1. Thus, the valve device 1 capable of achieving improved operability, durability, and airtightness can be provided.

[0034] Furthermore, according to the present embodiment, the internal thread member 72 can slide on the guide member 29 and be guided in the direction of the axial line L; therefore, inclination of the internal thread member 72 with respect to the direction of the axial line L and chatter can be suppressed, resulting in stabilization of the drive of the valve element 50.

[0035] Furthermore, according to the present embodiment, the guidance of the displacement of the female thread member 72 in the direction of the axial line L can be ensured by the guided surfaces 78a of the female thread member 72 sliding on the respective guiding surfaces 37 of the guide member 29. Therefore, the driving of the valve element 50 can be further stabilized. Furthermore, according to this structure, the guided surfaces 78a abut against the respective guiding surfaces 37, so that the rotation of the female thread member 72 around the axis of the axial line L can be restricted by the guiding surfaces 37. This can prevent the generation of sliding resistance around the axis between the first diaphragm 20 and the valve body 10, and can suppress the load in the rotational direction from being exerted on the spindle 71 and the female thread member 72.Furthermore, since the first diaphragm 20 does not slide on the valve body 10 around the axis, the wear of the first diaphragm 20 caused by the sliding can be suppressed.

[0036] Furthermore, according to the present embodiment, the displacement of the internally threaded member 72 in the direction of the axial line L can be guided at least at two locations by the at least two or more provided guide surfaces 37 sliding on the at least two or more provided respective guided surfaces 78a. Therefore, the driving of the valve element 50 can be further stabilized. Furthermore, the abutment of the guided surfaces 78a against the respective guide surfaces 37 means that the rotation of the internally threaded member 72 about the axis of the axial line L can be restricted at least at two locations. As a result, the above-described sliding of the first diaphragm 20 on the valve body 10 about the axis can be reliably prevented, and the load in the rotational direction can be reliably suppressed from being exerted on the spindle 71 and the internally threaded member 72.Furthermore, the wear of the first diaphragm 20 caused by sliding can be reliably suppressed.

[0037] Next, a first modification of the first embodiment will be explained. Fig. 4 is a cross-sectional view showing a valve closing state of the valve device 1 according to the first modification of the first embodiment. Fig. 5 is a cross-sectional view showing a valve opening state of the Fig. 4 shows the valve device 1. Fig. 6 is a cross-sectional view along line BB of Fig. 4. The valve device 1 according to the first modification includes an internal thread member 90. The internal thread member 90 corresponds to the internal thread member 72 of the first embodiment. The internal thread member 90 includes a first internal thread member 91 constituting the upper portion, a second internal thread member 92 constituting the lower portion, and a connecting member 93 connecting the first internal thread member 91 to the second internal thread member 92. That is, while the above-described internal thread member 72 is composed of one component, the internal thread member 90 is composed of multiple components. The first internal thread member 91 is tubularly formed by a resinous material, extending in the direction of the axial line L, and is disposed between the pair of guide portions 32. A first internal thread portion 94 is formed on the inner peripheral surface of the first internal thread member 91.The first internal thread portion 94 is screwed to the external thread portion 77 of the spindle 71. A first flange portion 95 is formed at the lower end portion of the first internal thread element 91, which projects diametrically outward.

[0038] The second internally threaded member 92 is formed into a tubular shape by means of a metallic or resinous material, extending in the direction of the axial line L. At the upper end portion of the second internally threaded member 92, a second flange portion 96 is formed, which projects diametrically outward. The second flange portion 96 is formed to have a larger diameter than the first flange portion 95. The upper surface of the second flange portion 96 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 against which the first flange portion 95 does not abut. By fixing the first flange portion 95 to the second flange portion 96, the first internally threaded member 91 is connected to the second internally threaded member 92.

[0039] According to this structure, with respect to the internal thread member 90, at least the first internal thread member 91 can be formed of resin, so that the sliding performance of the external thread portion 77 and the first internal thread portion 94 can be increased and wear of the first internal thread portion 94 can be suppressed. Furthermore, the first internal thread member 91 and the second internal thread member 92 are formed as separate components; therefore, the screwing of the first internal thread member 91 to the spindle 71 and the screwing of the second internal thread member 92 to the valve rod screw 44 can be performed separately. For this reason, it is not necessary to align the axes of the spindle 71 and the valve rod screw 44, and no consideration of axis offset is required, so that the construction of the valve device 1 can be simplified.

[0040] Next, a second modification of the first embodiment will be explained. Fig. 7 is a cross-sectional view showing a valve closing state of the valve device 1 according to the second modification of the first embodiment. Fig. 8 is a cross-sectional view showing a valve opening state of the Fig. 7. The valve device 1 according to the second modification comprises, as shown in Fig. 7, a guide member 100 and a screw feed unit 110. The guide member 100 corresponds to the guide member 29 of the first embodiment described above, and the screw feed unit 110 corresponds to the screw feed unit 70 of the first embodiment. The guide member 100 includes a tubular guide portion 102 extending from the central portion of a ceiling wall 101 opposite the first diaphragm 20 in the direction of the axial line L toward the bottom surface L2. A first internal thread portion 103 is formed on the inner peripheral surface of the guide portion 102.

[0041] The screw feed unit 110 includes a spindle 111 extending in the direction of the axial line L and a second screw feed member 112 connected to the lower end of the spindle 111. An upper end portion 113 of the spindle 111 is connected to the drive portion 60. This enables the spindle 111 to rotate about the axis of the axial line L. A large-diameter portion 114 is formed at the lower end portion of the spindle 111, which has a larger diameter than other parts of the spindle 111. Bearings 117, described later, are arranged on the upper surface L1 and the lower surface L2 of the large-diameter portion 114, respectively. A male-threaded portion 115 is formed on the outer peripheral surface of the central portion of the spindle 111 in the direction of the axial line L. The male-threaded portion 115 is screwed to the first female-threaded portion 103.In the second modification, there is no limitation on the displacement of the spindle 111 in the direction of the axial line L. When the spindle 111 is rotated by the drive section 60, the screw feeding is performed at the screwing section of the external thread section 115 and the first internal thread section 103, whereby the spindle 111 moves in the direction of the axial line L while the spindle 111 rotates around the axis of the axial line L.

[0042] The second screw feed member 112 includes a lower cylindrical portion 116 forming the portion located in the lower surface L2, bearings 117 that suppress the transmission of the rotational force of the spindle 111 to the lower cylindrical portion 116, and a cover 118 that houses the bearings 117. The lower cylindrical portion 116 corresponds to the second internally threaded member 92 of the first modification described above. A second internally threaded portion 119 is formed on the inner peripheral surface of the lower cylindrical portion 116 and is threadably engaged with the valve rod externally threaded portion 46 formed on the outer peripheral surface of the valve rod screw 44. A flange portion 120 projecting diametrically outward is formed on the upper end portion of the lower cylindrical portion 116.One of the bearings 117 is arranged between the flange portion 120 of the lower cylindrical portion 116 and the large-diameter portion 114 of the spindle 111. The other bearing 117 is arranged between the large-diameter portion 114 of the spindle 111 and the cover 118. Accordingly, the large-diameter portion 114 of the spindle 111 is clamped in the direction of the axial line L by the two bearings 117. The rolling element of the bearing 117 located in the upper surface L1 abuts against the upper surface of the large-diameter portion 114, and the rolling element of the bearing 117 located in the lower surface L2 abuts against the lower surface of the large-diameter portion 114. Thus, the rotational force of the spindle 111 is transmitted to the bearings 117, but not to the second screw feed member 112.The cover 118 covers the upper surface of the bearing 117 located in the top 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.

[0043] In the second modification, the valve device 1 is Fig. 7 by driving the drive section 60 in the position shown in Fig. 8. At this time, the rotational force of the drive section 60 is transmitted to the spindle 111, the spindle 111 rotates around the axis of the axial line L as described above, and the externally threaded section 115 displaces toward the top surface L1 by screw feeding. This displacement is transmitted to the second screw feeding member 112 via the large-diameter section 114, the bearings 117, and the cover 118, causing the second screw feeding member 112 to displace toward the top surface L1. Although the rotational force of the spindle 111 is transmitted to the bearings 117, it is not transmitted to the second screw feeding member 112; therefore, the second screw feeding member 112 displaces toward the top surface L1 while limiting rotation around the axis of the axial line L.Then, as in the first embodiment and the first modification, according to the displacement of the second screw feed member 112 toward the top surface L1, the first diaphragm 20 and the second diaphragm 39 shift toward the top surface L1, causing the valve member 50 to shift toward the top surface L1. According to this configuration, the present invention can be implemented using the valve device 1 having a structure for shifting the spindle 111 in the direction of the axial line L.

[0044] Next, a second embodiment of the present invention will be explained. Fig. 9 is a cross-sectional view showing a valve closing state of a valve device 200 according to the second embodiment. Fig. 10 is a cross-sectional view showing a valve opening state of the Fig. 9 shows the valve device 200. Fig. 11 is a cross-sectional view along the line CC of Fig. 9. The valve device 200 comprises, as in Fig. 9, a valve body 210 including a valve port 217 through which a fluid flows, a valve element 280 located inside the valve body 210 near or away from the valve port 217 in the direction of the axial line L (a displacement direction), a drive portion 260 for driving the valve element 280, a screw feed unit 270 for transmitting a driving force of the drive portion 260 to the valve element 280, and a bellows 290 (a sealing member). The valve body 210 includes a tubular body 211 extending in the cross direction X. At the end portion of the body 211 located on the left side X1, a first port 212 is formed, which opens in the cross direction X. At the end portion of the body 211 located on the right side X2, a second port 213 is formed, which opens in the crossing direction X.

[0045] A partition wall 214 is arranged inside the body 211, extending along the axial line A of the body 211 and separating the interior of the body 211 into the upper part and the lower part. The partition wall 214 is supported by a left vertical wall 215, which extends from the end portion of the partition wall 214 located on the left side X1 to the inner wall of the body 11 located on the bottom side L2, and a right vertical wall 216, which extends from the end portion of the partition wall 214 located on the right side X2 to the inner wall of the body 11 located on the top side L1, such that the partition wall 214 extends inside the body 11 in the crossing direction X. The valve port 217 is formed in the center of the partition wall 214 and extends in the direction of the axial line L. The upper end edge of the valve port 217 forms a valve seat portion 218.On the wall surface of the body 211 located in the upper side L1, a tubular supporting portion 219 is formed, which opens toward the upper side L1. On the inner peripheral surface of the upper end portion of the supporting portion 219, a step portion 220 is formed, which is recessed toward the lower side L2. A guide member 230, described later, engages with the step portion 220. On the upper surface of the supporting portion 219, a first supporting projection 221 is formed, which projects toward the upper side L1. On the outer peripheral surface of the upper end portion of the supporting portion 219, a first external thread portion 222 is formed.

[0046] The guide member 230 is formed in a cylindrical shape with a bottom opening toward the top surface L1, and a through hole 231 is formed on the bottom surface, which through hole 231 passes in the direction of the axial line L. The portion of an internally threaded member 272, which is located in the bottom surface L2 and will be 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 direction of the axial line L, and a guiding surface 232 parallel to the direction of the axial line L is formed in a part of the inner peripheral surface of the through-hole 231. Specifically, the guiding surface 232 is formed by the respective inner surfaces of the four V-grooves formed on the inner surface of the through-hole 231 such that the guiding surface 232 engages with the corner portions of the four corners of the portion located in the bottom surface L2 of the cuboid-shaped female thread member 272. A flange-shaped supported portion 233 is formed on the upper portion of the guide member 230 and projects diametrically outward over the entire circumference.The first support protrusion 221 of the above-described supporting portion 219 is fixed to the lower surface of the supported portion 233 through a gasket P. A method such as welding, soldering, brazing, etc. can be used for the fixing. A first receiving portion 234 is formed on the upper end surface of the guide member 230, projecting toward the upper surface L1 along the edge portion of the through-hole 231. The lower end portion of the bellows 290 (the sealing member) described later is fixed to the upper surface of the first receiving portion 234.

[0047] A cover 240 is mounted on the upper surface L1 of the guide member 230. The cover 240 includes a ceiling wall 241 and a side wall 242 extending from the outer edge portion of the ceiling wall 241 toward the lower surface L2. The ceiling wall 241 corresponds to the ceiling wall 30 of the guide member 29 of the first embodiment described above, and its detailed explanation is omitted or simplified. The ceiling wall 241 supports a spindle 271 described later such that the spindle 271 can rotate about the axis of the axial line L, and limits the displacement of the spindle 271 in the direction of the axial line L. A second support projection 243 is formed on the lower end surface of the side wall 242 and projects toward the lower surface L2. The second support projection 243 is fixed to the upper end surface of the supported portion 233 of the guide member 230 through the gasket P.For fastening, a method such as welding, soldering, brazing, etc. can be used. The supporting portion 219 and the cover 240 formed as above are circumferentially covered and fixed to each other with a nut member 250 that is screwed to the first externally threaded portion 222 of the supporting portion 219. Through this fixing, the supporting portion 219 (the valve body 210), the guide member 230, and the cover 240 are integrated with each other.

[0048] The screw feeding unit 70 includes the spindle 271 (the first screw feeding member) and the internally threaded member 272 (the second screw feeding member). A second externally threaded portion 273 is formed on the outer peripheral surface of the spindle 271. The internally threaded member 272 is columnar and extends in the direction of the axial line L. A guide hole 274 is formed in the center of the internally threaded member 272, opening toward the upper surface L1. A second internally threaded portion 275 is formed on the inner surface of the guide hole 274 and is screwed to the second externally threaded portion 273. A flange-shaped second receiving portion 276 is formed on the upper end portion of the internally threaded member 272 and projects diametrically outward. The upper end portion of the bellows 290 is attached to the lower surface of the second receiving portion 276.The portion of the female thread member 272 located in the bottom surface L2 is formed in a cuboid shape as described above, and with respect to its outer surface, the outer surface forming the corner portions of the four corners, as shown in . Fig. 11, a guided surface 278 which slides on the leading surface 232.

[0049] The bellows 290 is formed, for example, so as to be deformable in the direction of the axial line L by forming a metal plate material into a bellows shape by pressing, etc., and then forming it into a tubular shape so as to extend in the direction of the axial line L. The bellows 290 is arranged in a position where it covers the outer periphery of the female thread member 272 in the circumferential direction. The upper end portion of the bellows 290 is fixed to the lower surface of the second receiving portion 276 (the second screw feeding member), and the lower end portion of the bellows 290 is fixed to the upper surface of the first receiving portion 234 (the guide member 230 integrated with the valve body 210). That is, the bellows 290 is provided over the valve body 210 and the second screw feeding member. A method such as welding, soldering, brazing, etc. can be used to attach the bellows 290.The installation of the bellows 290 results in the separation of a space formed by the interior of the body 211 and the interior of the guide member 230 from a space formed by the interior of the cover 240. With this structure, the airtightness of the interior of the valve body 210 is maintained. According to this structure, the valve device 200 can be formed using the bellows 290 as a sealing element in addition to using the first diaphragm 20 as a sealing element.

[0050] The embodiments and modifications of the present invention have been described in detail above based on the figures; however, the specific structure is not limited thereto, and design changes, etc., are also within the scope of the present invention without departing from the gist of the present invention.

[0051] In the first embodiment, for example, the female threaded member 72 is guided in the direction of the axial line L, while the rotation of the female threaded member 72 around the axial line L is restricted by the sliding of the guide surfaces 37 provided on the guide member 29 on the respective guided surfaces 78a of the female threaded member 72. However, the rotation restriction of the female threaded member 72 and the guide configuration are not limited to this, and the following structure can also be used. That is, a pin is inserted into the female threaded member 72 in a direction orthogonal to the axial line L, and both end portions of the pin protrude in the direction orthogonal to the axial line L to form a projection portion. On the inner peripheral surface of the guide member 29, a groove portion into which the projection portion of the pin is engaged is formed such that the groove portion extends in the direction of the axial line L.The protrusion portion of the pin then slides on the inner wall surface of the groove portion, thereby guiding the female thread member 72 in the direction of the axial line L while limiting the rotation of the female thread member 72 about the axial line L. Also with this structure, the transmission of the rotational force of the drive portion 60 to the first diaphragm 20 can be suppressed. The above-described protrusion portion does not necessarily have to be made of a pin, but the protrusion portion can be formed with any structure. Alternatively, the protrusion portion may be provided on the guide member 29 side, and the groove portion may be provided on the female thread member 72 side. [List of reference symbols] L Axial line 1 valve device 17 Valve connection 10 valve bodies 20 first membrane (sealing element) 50 valve element 60 drive section 70 screw feeding unit 71 Spindle (first screw feeding element) 72 Internal thread element (second screw feed element) QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2006-266403

[0003]

Claims

[1] A valve device (1) comprising a valve body (10) comprising a valve port (17), a valve element (50) located in an interior of the valve body (10) approaching or spaced from the valve port (17), a drive portion (60) for driving the valve element (50), a screw feed unit (70) for transmitting a driving force of the drive portion (60) to the valve element (50), and a sealing element (20) for maintaining airtightness of the interior of the valve body (10), characterized by , that the screw feed unit (70) comprises a first screw feed element (71) which rotates about the axis by the driving force, and a second screw feed element (72) which is connected to the first screw feed element (71) and is connected to the valve element (50), that the second screw feed element (72) is displaced by the rotation of the first screw feed element (71) in a displacement direction of the valve element (50), while rotation about the axis is limited, and that the sealing element (20) is provided over the valve body (10) and the second screw feed element (72) and deforms in accordance with the displacement of the second screw feed element (72) in the displacement direction. [2] Valve device (1) according to claim 1, characterized by that a guide element is provided on the valve body (10) which causes the second screw feed element (72) to slide in the direction of displacement. [3] Valve device (1) according to claim 2, characterized by , that at least one guiding surface (37) is provided on the guide element, which is oriented parallel to the direction of displacement and that at least one guided surface (78a) is provided on the second screw feed element (72), on which the at least one guiding surface (37) slides. [4] Valve device according to claim 3, characterized by that at least two or more guiding surfaces (37) and at least two or more guided surfaces (78a) are provided. [5] Valve device according to claim 1, characterized by that the sealing element (20) is a membrane. [6] Valve device according to claim 1, characterized by that the sealing element (20) is a bellows (290).

Images