Connecting structure of valve body and valve shaft

Abstract

The invention provides a connecting structure of a valve body and a valve shaft, which can be used for retaining a threaded part by using a simple structure and can be used for loosening the threaded part according to needs. This connection structure for a valve body and a valve shaft is provided with: a threaded part (4) for connecting a plug (2) (valve body) and a valve rod (3) (valve shaft); and a pin (5) that traverses the plug (2) and the valve rod (3). A plug (2) on which a female thread (7) is formed has an annular groove (12). A stem (3) on which a male thread (8) is formed has a pin hole (24) extending in a direction orthogonal to the axial direction of a female thread (7) and into which a pin (5) is fitted. The pin hole (24) passes through the annular groove (12) and extends in the tangential direction of the annular groove (12) in a state where the male thread (8) is screwed to the female thread (7). The groove wall surface (12a) of the annular groove (12) has a semicircular cross-section and a shape into which the outer peripheral surface of the pin (5) is fitted.

Description

TECHNICAL FIELD

[0001] The present application relates to a structure for connecting a valve body and a valve shaft, and has a stopper structure for fixing a threaded portion of the valve body and the valve shaft. BACKGROUND

[0002] Conventionally, as a control valve, there is a control valve in which a valve stem as a valve shaft is screwed and fastened to a plug as a valve body, and the valve stem is connected to an actuator to drive the plug. In the case where the valve stem and the plug are fastened by a thread, in order to prevent the threaded portion from loosening due to the influence of vibration or heat at the time of use, a stopper is implemented. As a method of implementing the stopper, there is a method in which a taper pin is inserted after the valve stem is screwed to the plug to restrict the rotation of both, or a method in which both are welded after the plug is screwed to the valve stem.

[0003] [Related Art Literature] [Patent Literature] Patent Literature 1: Japanese Patent No. 6762165 SUMMARY [Problems to be Solved by the Invention] When the fastening portion of the valve stem and the plug is implemented with the stopper, if either the valve stem or the plug is damaged, it is not possible to replace only one of them, and both must be newly manufactured. In the case of a bellows valve in which a bellows is welded to the valve stem, since the bellows is an expensive part, it is not possible to replace only the plug, which is a problem. In addition, by using a spring pin instead of the taper pin, although it is possible to detach the plug from the valve stem, the spring pin can possibly fall off due to vibration at the time of use.

[0004] As a control valve which adopts the stopper structure and enables replacement of only the plug, there is a control valve described in Patent Literature 1. In the control valve, a pin is inserted through a notch formed in the outer peripheral portion of the plug so as to extend in the axial direction and a through hole which penetrates the valve stem in the radial direction, and the rotation is restricted, thereby preventing the threaded portion from loosening. The notch and the through hole are formed at a plurality of positions arranged at a predetermined interval in the circumferential direction of the plug.

[0005] In the control valve described in Patent Literature 1, the replacement of the plug can be implemented by the following operation, that is, the pin is removed and the valve stem is rotated with respect to the plug to loosen the threaded portion.

[0006] However, in the control valve, when the valve stem is assembled to the plug, the alignment of the notch and the through hole must be performed, and the notch and the through hole must be provided at a plurality of positions in the circumferential direction in such a manner that the alignment becomes easy.

[0007] An object of the present application is to provide a structure for connecting a valve body and a valve shaft, which enables the stopper of the threaded portion to be implemented with a simple structure, and enables the threaded portion to be loosened as needed.

[0008] [Technical Means for Solving the Problem] To achieve the aforementioned objective, the valve body and valve shaft connection structure of the present invention includes: a threaded portion provided in the valve body and valve shaft to connect the valve body and valve shaft; and a cylindrical pin transversely cutting the valve body and valve shaft, wherein the male threaded component of the valve body and valve shaft having the threaded portion has an annular groove. The female threaded component of the valve body and valve shaft having the threaded portion has a pin hole extending in a direction orthogonal to the axial direction of the female thread and for the pin to engage. The pin hole is formed such that, when the male thread is screwed into the female thread, it passes through the annular groove and extends in the tangential direction of the annular groove. The groove wall of the annular groove is formed such that, when viewed from a direction orthogonal to the circumferential direction, the annular groove has a semi-circular cross-section and is a shape for the outer circumferential surface of the pin to engage.

[0009] Alternatively, in the connection structure between the valve body and the valve shaft, the component with the male thread has a blocking portion. The blocking portion is screwed into the female thread by the male thread and abuts against the component with the female thread to limit further screwing. The state in which the male thread is screwed into the female thread is the state in which the blocking portion abuts against the component with the female thread.

[0010] The present invention can also be described as follows: in the connection structure between the valve body and the valve shaft, the female thread is formed in a threaded hole containing a non-through hole open at one end of the member having the female thread. A female thread portion having the female thread is provided on the opening side of the threaded hole. A circular recess is provided in the threaded hole further inward than the female thread portion. The pin hole is formed to cross the circular recess of the threaded hole. The member having the male thread has: the male thread, and a columnar portion formed on a frontal side further inward than the male thread. The columnar portion is shaped to fit into the circular recess. An annular groove is formed in the columnar portion of the member having the male thread.

[0011] The present invention can also be described as follows: in the connection structure between the valve body and the valve shaft, the female thread is formed in a threaded hole containing a non-through hole open at one end of the member having the female thread. On the opening side of the threaded hole, a portion containing a circular hole with a fixed diameter is provided. Further inside the threaded hole than the portion containing the hole, a portion having the female thread is provided. The pin hole is formed to intersect the portion containing the threaded hole. The member having the male thread has: the male thread located at the front end, and a columnar portion located further down than the male thread. The columnar portion is shaped to fit into the portion containing the hole. The annular groove is formed in the columnar portion of the member having the male thread.

[0012] Alternatively, in the connection structure between the valve body and the valve shaft, the pin may have a knurled outer periphery.

[0013] [The effects of the invention] According to the present invention, a connection structure between a valve body and a valve shaft can be provided, which can use a simple structure to prevent the threaded portion from retracting and can loosen the threaded portion as needed. Attached Figure Description

[0014] Figure 1 This is a front view showing the connection structure between the valve body and the valve shaft in the first embodiment.

[0015] Figure 2 It is a front view of the plug and valve stem, showing the plug with a portion disconnected.

[0016] Figure 3 It is a cross-sectional view that enlarges the main parts.

[0017] Figure 4 yes Figure 1 The cross-sectional view along line IV-IV in the diagram.

[0018] Figure 5A , Figure 5B These are front and side views of the pin.

[0019] Figure 6 This is a cross-sectional view showing the connection structure between the valve body and the valve shaft in the second embodiment.

[0020] Figure 7 This is a cross-sectional view showing the connection structure between the valve body and the valve shaft in the third embodiment.

[0021] Figure 8 This is a cross-sectional view showing the connection structure between the valve body and the valve shaft in the fourth embodiment.

[0022] Explanation of icon numbers 1: Connection structure 2: Plug (valve body) 3: Valve stem (valve shaft) 4: Threaded section 5: Sales 6: Control valve 7: Female thread 8: Male thread 11: Columnar part 12: Annular groove 18: Blocking section 23: Threaded hole 23a: Female thread section 23b: Circular recess 23c: Hole 24: Pin hole 25: Protrusion Detailed Implementation (First Implementation) The following is for reference Figures 1-5B This section will describe in detail one embodiment of the connection structure between the valve body and the valve shaft of the present invention. In this embodiment, an example of applying the connection structure between the valve body and the valve shaft of the present invention to a control valve will be described.

[0023] Figure 1 The connecting structure 1 between the valve body and the valve shaft shown (hereinafter referred to as connecting structure 1) is... Figure 1 The plug 2, which serves as the valve body, is depicted in the lower half of the diagram. Figure 1 The structure depicted in the upper half connects the valve stem 3, which serves as the valve shaft. The connection structure 1 in this embodiment includes: a threaded portion 4, which is provided on the plug 2 and the valve stem 3 to connect the plug 2 and the valve stem 3; and a cylindrical pin 5, which cuts across the plug 2 and the valve stem 3.

[0024] The plug 2 and the valve stem 3 constitute the valve section of the regulating valve 6, and are used in a state where they are connected to each other as an integral unit via the threaded portion 4. The material forming the plug 2 and the valve stem 3 is metal.

[0025] like Figure 2 As shown, the threaded portion 4 in this embodiment includes a female thread 7 formed on the plug 2 and a male thread 8 formed on the valve stem 3.

[0026] The valve stem 3, which has a male thread 8, is integrally cylindrical in shape and has a cylindrical columnar portion 11 formed on a side closer to the front end of the male thread 8, an annular groove 12 formed in the columnar portion 11 near the male thread 8, and a shaft portion 13 formed on a side opposite to the annular groove 12, which is closer to the male thread 8. The shaft portion 13 is formed with an outer diameter larger than that of the male thread 8, such as... Figure 1 As shown, the actuator 16 of the regulating valve 6 extends through the connecting rod 14 and through the interior of the bellows 15 toward the opposite side of the male thread 8.

[0027] The connecting rod 14 is formed into an annular shape for fitting into the shaft portion 13 and is welded to the shaft portion 13, and one end of the bellows 15 is welded thereto. The other end of the bellows 15 is detachably fixed to the shaft seal portion (not shown) of the regulating valve 6 via a sealing member.

[0028] The annular groove 12 is a groove that extends uninterruptedly along the circumference of the valve stem 3. For example... Figure 3As shown, the groove wall surface 12a of the annular groove 12 is formed such that the annular groove 12 has a semi-circular cross-section when viewed from a direction orthogonal to the circumference. The radius of curvature of the arc forming the semi-circular cross-section of the groove wall surface 12a is formed to be consistent with the radius of curvature of the outer peripheral surface of the pin 5. In this embodiment, the groove wall surface 12a of the annular groove 12 is formed to allow the outer peripheral surface of the pin 5 to fit in the pressed-in state.

[0029] like Figure 3 As shown, the shaft portion 13 of the valve stem 3 is formed such that it abuts against the end face 2a of the plug 2 when the male thread 8 is screwed into the female thread 7 of the plug 2 by a predetermined amount. Therefore, the shaft portion 13 constitutes a blocking portion 18, which abuts against the plug 2 when the male thread 8 is screwed into the female thread 7, thereby restricting its further screwing. In this embodiment, the shaft portion 13 abuts against the end face 2a of the plug 2, thus achieving the state where the male thread 8 is screwed into the female thread 7.

[0030] Embolist 2 has: Figure 2 The image depicts a disc-shaped body portion 21 at the bottom and a cylindrical connecting portion 22 protruding from the body portion 21. The body portion 21 reciprocates along the axial direction, thereby contacting / moving away from a valve seat (not shown).

[0031] At the end of the connecting portion 22 of the plug 2 opposite to the body portion 21, a threaded hole 23 with the female thread 7 is formed. The threaded hole 23 is a non-through hole that opens at one end of the plug 2, i.e., the end face 2a, and extends along the axial direction of the plug 2.

[0032] On the opening side of the threaded hole, a female thread portion 23a with a female thread 7 is provided. In the threaded hole, a circular recess 23b is provided further inside than the female thread portion 23a.

[0033] The columnar portion 11 located at the front end of the valve stem 3 is shaped to fit into the circular recess 23b.

[0034] A pin hole 24, including a through hole, is provided at the boundary between the circular recess 23b and the female threaded portion 23a. The opening shape of the pin hole 24 is circular. The diameter of the pin hole 24 is the diameter at which the pin 5 is engaged in the pressed-in state. That is, the radius of curvature of the circle forming the cross-sectional shape of the pin hole 24 is the same as the radius of curvature of the arc forming the cross-sectional shape of the annular groove 12.

[0035] The pin hole 24 is formed as a transversely tangential circular recess 23b, and as shown in the figure. Figure 4 As shown, it extends in a direction orthogonal to the axial direction of the female thread 7 (the axial direction of the plug 2). In this embodiment, the pin hole 24 penetrates the plug 2 in a direction orthogonal to the axial direction of the female thread 7.

[0036] like Figure 3As shown, the axial direction of plug 2 is ( Figure 3 The pin hole 24 (located in the vertical direction) is positioned as follows: with the male thread 8 of the valve stem 3 screwed into the female thread 7 of the plug 2 (the shaft 13 abutting against the plug 2), the pin hole 24 passes through the annular groove 12 of the valve stem 3 and extends along the tangential direction of the annular groove 12. In detail, the structure is such that when the portion of the pin hole 24 that cuts across the annular groove 12 is viewed from a direction orthogonal to the long side of the pin hole 24, the groove wall surface 12a of the annular groove 12 and the hole wall surface 24a of the pin hole 24 become opposite each other, forming a circular opening. This circular opening is connected to the pin hole 24 without any step difference.

[0037] like Figure 5A , Figure 5B As shown, pin 5 is formed into a cylindrical shape of a specified length. Figure 5A This is a front view of the Selling 5. Figure 5B This is a side view of pin 5. In this embodiment, pin 5 has a knurled outer peripheral surface. The knurling is performed to create unevenness on the outer peripheral surface of pin 5, thereby preventing it from falling out through frictional resistance when pin 5 is inserted into pin hole 24. Figure 5A , Figure 5B As an example of a pin 5 subjected to knurling, the illustration shows a pin 5 with a large number of protrusions 25 formed on its outer peripheral surface. The protrusions 25 extend from one end of the pin 5 along its long side to the other end, and are formed at multiple circumferential positions on the outer peripheral surface of the pin 5 at equal intervals. Furthermore, the irregularities formed by knurling are not limited to... Figure 5A , Figure 5B The numerous protrusions shown in Figure 25 can be modified as appropriate.

[0038] The annular groove 12 and the pin hole 24 are formed such that the pin 5 is engaged in a pressed state in which the protruding end of the protrusion formed by knurling undergoes slight elastic deformation or plastic deformation.

[0039] To connect the valve stem 3 to the plug 2 via the connection structure 1 constructed as described above, the front end portion (cylindrical portion 11) of the valve stem 3 is inserted into the threaded hole 23 of the plug 2, and the male thread 8 is screwed into the female thread 7. With the male thread 8 screwed into the female thread 7, the cylindrical portion 11 of the valve stem 3 fits into the circular recess 23b of the threaded hole 23. Furthermore, with the male thread 8 further screwed into the female thread 7, the shaft portion 13 (blocking portion 18) of the valve stem 3 abuts against the end face 2a of the plug 2, restricting further screwing.

[0040] By screwing the male thread 8 to the female thread 7 as shown, the annular groove 12 of the valve stem 3 and the pin hole 24 of the plug 2 are positioned in the same position along the axial direction of the female thread 7. In this state, the pin 5 is pressed into the pin hole 24 of the plug 2. The pressing operation is performed by aligning one end of the pin 5 with one end of the pin hole 24 and tapping the other end of the pin 5 toward one end with a tool (not shown). Through this pressing operation, the pin 5 enters the plug 2 from one end of the pin hole 24 and cuts through the annular groove 12 to reach the other end of the pin hole 24. That is, the pin 5 is pressed into the pin hole 24 and is thus received in the engaged state.

[0041] With pin 5 inserted into pin hole 24, the relative movement of valve stem 3 and plug 2 toward the axial direction is restricted by pin 5, so threaded part 4 will not loosen.

[0042] When replacing either the plug 2 or the valve stem 3, remove the pin 5 from the plug 2 and loosen the threaded portion 4 to separate the plug 2 from the valve stem 3. Regarding the removal of the pin 5, one end of the pin 5 can be tapped towards the other end to push the pin 5 out of the pin hole 24, or the pin 5 can be cut into the pin hole 24 by drilling a hole in the axial portion of the pin 5. Therefore, the plug 2 can be separated from the valve stem 3 without damaging the pin hole 24 or the annular groove 12, thus allowing the reuse of one of these parts that does not need to be replaced.

[0043] Therefore, according to this embodiment, a connection structure between the valve body and the valve shaft can be provided, which can use a simple structure to prevent the threaded portion from retracting, and can loosen the threaded portion as needed.

[0044] In this embodiment, the component (valve stem 3) having a male thread 8 has a blocking portion 18, which abuts against the component (plug 2) having a female thread 7 by being screwed into the female thread 7 through the male thread 8, thereby limiting further screwing in. The state in which the male thread 8 is screwed into the female thread 7 is the state in which the blocking portion 18 abuts against the valve stem 3.

[0045] Therefore, the annular groove 12 and the pin hole 24 can be aligned with good accuracy and with ease, thus providing a connection structure for the valve body and valve shaft that can be easily connected.

[0046] In this embodiment, the female thread 7 is formed as a threaded hole 23 containing a non-through hole open at one end of the member (plug 2) to which the female thread 7 is formed. A female thread portion 23a with the female thread 7 is provided on the opening side of the threaded hole 23. A circular recess 23b is provided in the threaded hole 23 further inward than the female thread portion 23a. The pin hole 24 is formed as a circular recess 23b that crosses the threaded hole 23. The member (valve stem 3) with the male thread 8 has the male thread 8 and a columnar portion 11 formed on the front end side of the male thread 8. The columnar portion 11 is shaped to fit into the circular recess 23b. An annular groove 12 is formed in the columnar portion 11 of the valve stem 3.

[0047] Therefore, pin 5 will not cut across the threaded portion 4. Thus, compared to the case where pin 5 cuts across the threaded portion 4, it can be firmly held between the plug 2 and the valve stem 3, and the reliability of the anti-reverse mechanism of the threaded portion 4 provided by pin 5 is higher.

[0048] Furthermore, in the connection structure 1 of this embodiment, the female thread 7 of the threaded hole 23 is formed on the opening side of the threaded hole 23. Therefore, the female thread 7 can be machined near the end face 2a of the plug 2, thus making thread machining easy.

[0049] By forming the female thread 7 on the opening side of the threaded hole 23, the pin hole 24 is formed at a position at least a distance away from the end face 2a of the plug 2 corresponding to the female thread 7. The insertion or removal of the pin 5 is performed with both ends of the plug 2 supported by a support member (not shown). According to this embodiment, the pin hole 24 is formed away from the end face 2a of the plug 2, so when these operations are performed, a large space for support can be formed between the pin hole 24 and both ends of the plug 2, the support of the plug 2 is stable, and therefore the insertion or removal of the pin hole 24 can be easily performed.

[0050] In this embodiment, the pin 5 has a knurled outer periphery. Therefore, the frictional resistance generated at the contact points between the pin 5 and the groove wall 12a of the annular groove 12 and the hole wall 24a of the pin hole 24 can be used to prevent the pin 5 from falling off.

[0051] (Second Implementation) The position of the pin-cut plug and the valve stem can be like... Figure 6 Change it to the inside of the threaded hole as shown. Figure 6 In the middle, for the passage Figures 1-5B For components that are the same or equivalent as those described, the same reference numerals shall be attached and detailed descriptions shall be omitted where appropriate.

[0052] Figure 6 The annular groove 12 shown is formed on the front end side of the columnar portion 11. Furthermore, Figure 6The pin hole 24 shown is formed near the bottom of the circular recess 23b. The positions where these annular grooves 12 and pin holes 24 are formed are as long as... Figure 6 The range indicated by the two-point chain line A can be appropriately changed.

[0053] Even with a structure like pin 5 that cuts across the bottom side of the threaded hole 23 (the front end side of the valve stem 13), it is possible to provide a connection structure between the valve body and the valve shaft in the same way as in the first embodiment. This allows for locking of the threaded portion using a simple structure, and the threaded portion can be loosened as needed.

[0054] exist Figure 6 In the connection structure 1 shown, the female thread 7 of the threaded hole 23 is also formed on the opening side of the threaded hole 23. Therefore, the female thread 7 can be machined near the end face 2a of the plug 2, thus making thread machining easy.

[0055] By forming the female thread 7 on the opening side of the threaded hole 23, the pin hole 24 is formed at a position at least a distance away from the end face 2a of the plug 2 corresponding to the female thread 7. The insertion or removal of the pin 5 is performed with both ends of the plug 2 supported by a support member (not shown). According to this embodiment, the pin hole 24 is formed away from the end face 2a of the plug 2, so when these operations are performed, a large space for support can be formed between the pin hole 24 and both ends of the plug 2, the support of the plug 2 is stable, and therefore the insertion or removal of the pin hole 24 can be easily performed.

[0056] (Third implementation method) The position of the pin-cut plug and the valve stem can be like... Figure 7 Change it to the opening side of the threaded hole as shown. Figure 7 In the middle, for the passage Figures 1-5B For components that are the same or equivalent as those described, the same reference numerals shall be attached and detailed descriptions shall be omitted where appropriate.

[0057] exist Figure 7 The threaded hole 23 shown has an opening side with a hole portion 23c containing a circular hole with a fixed diameter. Furthermore, a female thread portion 23a with a female thread 7 is provided in the threaded hole 23 further inside than the hole portion 23c.

[0058] Figure 7 The pin hole 24 shown is formed as a hole portion 23c of a transverse threaded hole 23.

[0059] Figure 7 The valve stem 13 shown has a male thread 8 at the front end and a thread located further down than the male thread 8 (opposite to the front end of the valve stem 13 and in...) Figure 7The columnar portion 11 (located on the upper side) is formed in the shape of a hole portion 23c that fits into the threaded hole 23.

[0060] In this embodiment, the annular groove 12 is also formed on the columnar portion 11 of the valve stem 13.

[0061] The positions where these annular grooves 12 and pin holes 24 are formed are as long as they are in Figure 7 The range indicated by the two-point chain line B can be appropriately changed.

[0062] Even with a structure like pin 5 that cuts across the opening side of the threaded hole 23 (the bottom end side of the valve stem 13), it is possible to provide a connection structure between the valve body and the valve shaft in the same way as in the first embodiment. This allows for locking of the threaded portion using a simple structure, and the threaded portion can be loosened as needed.

[0063] Figure 7 In the connecting structure 1 shown, the female thread 7 of the threaded hole 23 is formed on the inner side of the threaded hole 23. Therefore, a hole portion 23c with a fixed diameter can be formed on the opening side of the threaded hole 23, allowing the columnar portion 11 of the valve stem 3 to fit into the hole portion 23c, thereby aligning the plug 2 with the core of the valve stem 3. To improve the accuracy of the core alignment, the accuracy of the cylindrical surface of the hole wall of the hole portion 23c and the cylindrical surface of the outer peripheral surface of the columnar portion 11 must be improved. By forming the female thread 7 on the inner side of the threaded hole 23, the cylindrical surface (the hole wall of the hole portion 23c) on the plug 2 side is close to the end face 2a of the plug 2, thereby enabling easy and accurate machining of the cylindrical surface.

[0064] Furthermore, by forming the female thread 7 inside the threaded hole 23, the pin hole 24 is positioned close to the end face 2a of the plug 2. Therefore, when the pin hole 24 is machined, it is easy to improve the accuracy of the distance from the end face 2a to the pin hole 24.

[0065] As shown in the first to third embodiments, it is reasonable for the product to form an annular groove 12 on the columnar portion 11 of the valve stem 3, form a pin hole 24 on the circular recess 23b or hole 23c of the threaded hole 23 that does not have a female thread 7, and insert a pin 5 into the annular groove 12 and the pin hole 24. However, in the case of adopting a structure in which the female thread 7 is formed inside the threaded hole 23, although not shown, another hole with a fixed diameter can be formed inside the threaded hole 23, which is closer to the female thread 7, and the pin hole 24 can be formed by transversely cutting through this hole. In this case, a cylindrical portion that fits into the other hole is provided at the front end of the valve stem 3, which is closer to the front end of the male thread 8, and an annular groove 12 is formed in the cylindrical portion.

[0066] (Fourth Implementation) The blocking part that restricts further screwing in when the male thread is screwed into the female thread can be like...Figure 8 It is constructed as shown. Figure 8 In the middle, for the passage Figures 1-5B For components that are the same or equivalent as those described, the same reference numerals shall be attached and detailed descriptions shall be omitted where appropriate.

[0067] Figure 8 The threaded hole 23 of the plug 2 shown has a flat bottom surface 31 at its innermost part. The bottom surface 31 is a circular surface extending in a direction orthogonal to the axis of the female thread 7.

[0068] Moreover, in Figure 8 The valve stem 3 shown has a flat front end face 32 that can be tightly connected to the flat surface 31. Because the front end face 32 is tightly connected to the bottom surface 31 of the threaded hole 23, the male thread 8 cannot be further screwed into the female thread 7. Therefore, in this embodiment, the front end face 32 of the valve stem 3 constitutes the blocking portion 18 of this embodiment.

[0069] Even in a form where the front end of the valve stem 3 forms the blocking part 18, the blocking part 18 can be used to accurately and easily align the annular groove 12 with the pin hole 24, thus providing a connection structure between the valve body and the valve shaft that can be easily connected.

[0070] The screw-in limiting structure where the front end of the valve stem 3 becomes the blocking part 18 can be applied without relying on the location forming the annular groove 12 and the pin hole 24. That is, the screw-in limiting structure where the front end of the valve stem 3 becomes the blocking part 18 can be applied when using a structure like... Figures 1-3 , Figure 6 , Figure 8 As shown, a female thread 7 is formed on the opening side of the threaded hole 23, in a shape similar to... Figure 7 This applies to any configuration where the female thread 7 is formed on the inside of the threaded hole 23, as shown.

[0071] The embodiments described illustrate an example of applying the invention to a regulating valve 6, which is a bellows valve, in which a bellows 15 is welded to the valve stem 3. However, the invention is not limited to this and can also be used for fastening the plug and valve stem of a general valve.

[0072] In the described embodiment, an example was given where the male thread 8 of the valve stem 3 is screwed into the female thread 7 formed on the plug 2. However, the connection structure between the valve body and the valve shaft of the present invention is applicable even when the plug 2 has a male thread 8 and the valve stem 3 has a female thread 7. Even with this structure, the threaded portion can be locked using a simple structure, and the threaded portion can be loosened as needed.

Claims

1. A valve body and valve shaft coupling structure, characterized by, Comprise: a threaded portion provided to a valve body and a valve shaft of a valve to join the valve body and the valve shaft; and a cylindrical pin intersecting the valve body and the valve shaft, wherein a member of the valve body and the valve shaft in which a male thread of the threaded portion is formed has an annular groove, a member of the valve body and the valve shaft in which a female thread of the threaded portion is formed has a pin hole extending in a direction orthogonal to an axial direction of the female thread and into which the pin is fitted, the pin hole is formed so as to extend through the annular groove in a tangential direction of the annular groove in a state where the male thread is screwed to the female thread, a groove wall surface of the annular groove is formed in a shape in which the annular groove is a semicircular cross section when viewed from a direction orthogonal to a circumferential direction and into which an outer peripheral surface of the pin is fitted.

2. The valve body and valve shaft joining structure according to claim 1, wherein the member in which the male thread is formed has a blocking portion, the blocking portion abuts against the member in which the female thread is formed by screwing the male thread into the female thread to restrict further screwing thereof, the state where the male thread is screwed to the female thread is a state where the blocking portion abuts against the member in which the female thread is formed.

3. The valve body and valve shaft joining structure according to claim 1 or 2, wherein the female thread is formed in a threaded hole including a non-through hole open at one end of the member in which the female thread is formed, a female threaded portion in which the female thread is formed is provided on an open side of the threaded hole, a circular recess is provided in the threaded hole on a side further inside than the female threaded portion, the pin hole is formed so as to intersect the circular recess of the threaded hole, the member in which the male thread is formed has the male thread and a cylindrical portion formed on a side further forward than the male thread, the cylindrical portion is formed in a shape fitted in the circular recess, the annular groove is formed in the cylindrical portion of the member in which the male thread is formed.

4. The valve body and valve shaft joining structure according to claim 1 or 2, wherein the female thread is formed in a threaded hole including a non-through hole open at one end of the member in which the female thread is formed, a hole portion including a circular hole having a fixed hole diameter is provided on an open side of the threaded hole, a female threaded portion in which the female thread is formed is provided in the threaded hole on a side further inside than the hole portion, the pin hole is formed so as to intersect the hole portion of the threaded hole, the member in which the male thread is formed has the male thread on a front end portion and a cylindrical portion on a side further bottomward than the male thread, the cylindrical portion is formed in a shape fitted in the hole portion, the annular groove is formed in the cylindrical portion of the member in which the male thread is formed.

5. The valve body and valve shaft joining structure according to claim 1, wherein the pin is knurled on an outer peripheral portion.

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