Valve Drive Unit

Abstract

A valve drive device capable of suppressing cracking of components due to ultrasonic welding is provided. [Solution] The valve drive device (1) includes a case (10) that houses a motor (2) and an output shaft (5), a holder (20), and a fastening member (30) attached to the outer periphery of the holder (20) and connected to a valve body via the fastening member (30) having a threaded portion (31) formed on its inner circumferential surface. The holder (20) includes a holder-side cylindrical portion (21) into which a case-side cylindrical portion (16) that protrudes from a flat portion of the case (10) fits. The fastening member (30) includes a small-diameter portion (32) that protrudes inward from the threaded portion (31), and the small-diameter portion (32) is disposed between a flange (22) of the holder (20) and the flat portion of the case (10). The holder-side cylindrical portion (21) and the case-side cylindrical portion (16) are welded via a weld portion extending circumferentially. The case-side cylindrical portion (16) includes a rotation-stopping protrusion (18) that fits into a notch (24) that is a cutout formed by cutting out a portion of the circumferential surface of the holder-side cylindrical portion (21). The notch 24 has an arcuate portion connecting a pair of side surfaces that face each other in the circumferential direction.

Description

[Technical Field]

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

[0002] Conventionally, a valve device that controls the presence or absence and flow rate of a fluid such as water has been used, in which a valve body with a valve element inside is connected to a valve drive device that has an actuator such as a motor that drives the valve element.The connection structure between the valve drive device and the valve body generally employs a structure in which a flange on the valve body is abutted against a flange on a case of the valve drive device, and the flanges are fastened together with bolts.

[0003] Patent Document 1 describes a motor-operated valve as a valve device. The motor-operated valve of Patent Document 1 includes a valve body provided with a valve chamber connected to a flow path pipe, a valve element disposed in the valve chamber, and a motor assembly as a valve drive device that drives the valve element. Patent Document 1 describes a structure that uses a cap nut as a connection structure between the valve body and the motor assembly, rather than a structure in which flanges are fastened together with bolts.

[0004] A cylindrical female-threaded member with a female thread on its outer periphery is fixed to the motor assembly in Patent Document 1. The female-threaded member is connected to the valve body via a cap nut. The motor assembly includes a stepping motor and a reduction gear train arranged inside a case, and an output shaft positioned opposite the female-threaded member and extending toward the valve chamber. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-270853 Summary of the Invention [Problem to be solved by the invention]

[0006] When the valve drive unit and the valve body are connected by bolting flanges together, water can seep in from the point where the flanges on the valve body and the flanges on the valve drive unit meet, potentially causing the valve drive unit to malfunction. Conventionally, a rubber sheet or similar material has been inserted between the abutting flanges to seal the gap between the flanges and improve waterproofing.

[0007] However, in a fastening structure using a cap nut, the part that fits inside the cap nut (the internally threaded member in Patent Document 1) must be a separate part from the case of the valve drive device. As a result, there is a risk of water seeping in through the joint surface between the case of the valve drive device and the part that fits inside the cap nut, so it is necessary to improve the waterproofing performance of this area. For example, waterproofing can be improved by providing a welding structure using ultrasonic welding on the joint surface.

[0008] However, parts joined by ultrasonic welding may be subject to cracks due to vibrations during welding. In particular, if a part has a recess formed therein, cracks are likely to occur starting from the corners if the recess has a shape with corners.

[0009] In a fastening structure using a cap nut, the part that fits inside the cap nut needs to be provided with a circumferential positioning structure to prevent rotation relative to the case. For example, a recess is provided in the part that fits inside the cap nut, and the part is positioned in the circumferential direction by fitting into a protrusion provided on the case. Therefore, if the shape of the recess for positioning is rectangular, the part will be split starting from the corner. There is a risk of leakage.

[0010] In view of the above problems, an object of the present invention is to suppress cracking of parts due to ultrasonic welding when the connection point between a valve drive device and a valve body is made more waterproof by using a connection structure with a fastening member such as a cap nut with a threaded portion on its inner surface in combination with ultrasonic welding. [Means for solving the problem]

[0011] In order to solve the above problems, one aspect of the valve drive device according to the present invention is a valve drive device connected to a connection part of a valve body via a fastening member having a threaded portion formed on an inner peripheral surface thereof, the valve drive device comprising: a motor; an output shaft to which rotation of the motor is transmitted; a case accommodating the motor and the output shaft; a holder fixed to the case; and the fastening member attached to an outer periphery of the holder, wherein the case comprises a flat portion having an opening at a position overlapping with the output shaft as viewed in an axial direction along the rotation axis of the output shaft; and a case-side cylindrical portion protruding from the flat portion to one side in the axial direction and surrounding the opening, and the holder comprises a holder-side cylindrical portion into which the case-side cylindrical portion fits. the fastening member has a small diameter portion that protrudes more inward than the threaded portion, the holder side cylindrical portion is passed inside the small diameter portion, and the small diameter portion is disposed between the flat portion and the flange portion, the holder side cylindrical portion and the case side cylindrical portion are welded via a welding portion that extends circumferentially of the holder side cylindrical portion and the case side cylindrical portion, the holder side cylindrical portion has a notch portion cut out in part of the circumferential direction, the case side cylindrical portion has a rotation prevention protrusion that fits into the notch portion, and the notch portion has a pair of side portions facing each other in the circumferential direction and an arc portion connecting the pair of side portions. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view of the exterior of the valve drive device. [Figure 2] FIG. 2 is a cross-sectional view of the valve drive device (a cross-sectional view taken along the line AA in FIG. 1). [Figure 3] FIG. 3 is an exploded perspective view of the valve drive device. [Figure 4] FIG. 4 is a plan view of the valve drive device as seen from one side in the axial direction. [Figure 5] FIG. 5 is a side view showing a state in which the holder is attached to the case-side cylindrical portion. [Figure 6]FIG. 6 is an exploded cross-sectional view showing the welding recess of the holder and the welding protrusion of the case-side cylindrical portion. [Figure 7] FIG. 7 is an enlarged cross-sectional view of the welded portion. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of the valve drive device 1 will be described with reference to the drawings.

[0014] FIG. 1 is an external perspective view of the valve drive device 1. FIG. 2 is a cross-sectional view of the valve drive device 1 taken along the line AA in FIG. 1. FIG. 3 is an exploded perspective view of the valve drive device 1. FIG. 4 is a plan view of the valve drive device 1 as viewed from one side L1 in the axial direction. As shown in FIGS. 1 and 2, the valve drive device 1 is fixed to a connection portion 101 of a valve body 100. As shown in FIG. 2, a driven member 102 extending toward the valve drive device 1 is disposed inside the connection portion 101. The driven member 102 is a member for driving a valve body (not shown) provided in the valve body 100. A threaded portion 103 is formed on the outer circumferential surface of the connection portion 101.

[0015] As shown in FIGS. 2 and 3, the valve drive device 1 includes a motor 2, an output member 3, a gear train 4 that transmits the rotation of the motor 2 to the output member 3, a case 10 that houses the motor 2, the gear train 4, and the output member 3, a holder 20 fixed to the case 10, and a gear attached to the outer periphery of the holder 20. 2 and 3, the output member 3 includes an output shaft 5 and a gear unit 6 formed integrally with the output shaft 5. The gear unit 6 meshes with the final gear of the gear train 4. The output shaft 5 is connected to a driven member 102 of the valve body 100.

[0016] In the following description, the direction along the rotation axis L of the output shaft 5 is referred to as the axial direction. One side of the axial direction is referred to as L1, and the other side of the axial direction is referred to as L2. One side of the axial direction, L1, is the direction toward the tip of the output shaft 5.

[0017] As shown in Figures 1 and 3, case 10 comprises first case 11 and second case 12 that face each other in the axial direction. First case 11 and second case 12 are joined by four screws 13. As shown in Figures 2 and 3, an O-ring 14 is disposed around the entire periphery where the outer edges of first case 11 and second case 12 abut. Therefore, the gap between first case 11 and second case 12 is sealed by O-ring 14, preventing water from entering through the joint between first case 11 and second case 12.

[0018] As shown in FIG. 3, the motor 2 is housed inside the second case 12 located on the other axial side L2. The first case 11 has a flat portion 15 that overlaps the motor 2, gear train 4, and output member 3 from one axial side L1, and a case-side cylindrical portion 16 that protrudes from the flat portion 15 toward the one axial side L1. The flat portion 15 has a circular opening 17 that penetrates the flat portion 15 at a position that overlaps with the output shaft 5 in the axial direction, and the case-side cylindrical portion 16 surrounds the opening 17. As shown in FIG. 2, the output shaft 5 extends through the opening 17 toward the one axial side L1 of the flat portion 15. The opening 17 functions as a bearing that rotatably supports the output shaft 5. The case-side cylindrical portion 16 is arranged coaxially with the output shaft 5 that protrudes from the opening 17.

[0019] 2, a holder 20 is fixed to the case-side cylindrical portion 16. The holder 20 includes a holder-side cylindrical portion 21 into which the case-side cylindrical portion 16 fits, and an annular flange portion 22 that protrudes outward from the end of one side L1 in the axial direction of the holder-side cylindrical portion 21. The case-side cylindrical portion 16 fits into an annular recess 23 provided on the inner peripheral surface of the holder-side cylindrical portion 21.

[0020] The holder 20 is fixed to the connection portion 101 of the valve body 100 by the fastening member 30. As a result, the case 10 is fixed to the connection portion 101 via the holder 20. The fastening member 30 is a cap nut with a threaded portion 31 provided on its inner circumferential surface. The threaded portion 31 of the fastening member 30 screws into a threaded portion 103 provided on the outer circumferential surface of the connection portion 101. The fastening member 30 has a small diameter portion 32 that protrudes more inward than the threaded portion 31. The small diameter portion 32 is located at the end of the fastening member 30 on the other axial side L2.

[0021] When attaching the holder 20 to the case side cylindrical portion 16, the holder side cylindrical portion 21 is passed through the small diameter portion 32 of the fastening member 30 and then fitted onto the outer periphery of the case side cylindrical portion 16. As a result, as shown in Fig. 2, the holder side cylindrical portion 21 protrudes from the inside of the small diameter portion 32 to the other side L2 in the axial direction, and the assembly can be completed in a state where the small diameter portion 32 of the fastening member 30 is positioned between the flange portion 22 of the holder 20 and the flat portion 15 of the first case 11. The tip of the output shaft 5 protruding from the case side cylindrical portion 16 is positioned inside the holder side cylindrical portion 21.

[0022] (Holder positioning structure) Fig. 5 is a side view showing the holder 20 attached to the case side cylindrical portion 16. In Fig. 5, the fastening member 30 attached to the outer periphery of the holder 20 is not shown. As shown in Figs. 3 and 5, the holder 20 has a notch 24 formed by cutting out a part of the circumferential direction of the holder side cylindrical portion 21 towards one side L1 in the axial direction. A rotation stopper protrusion 18 protruding from the outer periphery of the case side cylindrical portion 16 fits into the notch 24. By fitting the rotation stopper protrusion 18 into the notch 24, the holder 20 is positioned in the circumferential direction relative to the case side cylindrical portion 16. Rotation stopper protrusion The end of the portion 18 on the other side L2 in the axial direction is connected to the flat portion 15 of the first case 11.

[0023] The notch portion 24 includes a pair of side surface portions 241, 242 that face each other in the circumferential direction of the holder-side cylindrical portion 21, and an arc portion 243 that connects the ends of the pair of side surface portions 241, 242 on one side L1 in the axial direction. The pair of side surface portions 241, 242 extend parallel to the axial direction. The arc portion 243 is a semicircle that convex toward one side L1 in the axial direction.

[0024] When the anti-rotation protrusion 18 fits into the cutout 24, each of the pair of side surfaces 241, 242 comes into contact with the anti-rotation protrusion 18 in the circumferential direction. An end portion on one axial side L1 of the anti-rotation protrusion 18 is a flat surface perpendicular to the axial direction. Therefore, a gap S in the axial direction is formed between the anti-rotation protrusion 18 and the arc portion 243 of the cutout 24.

[0025] (Method of connecting the valve drive device to the valve body) When connecting the valve drive device 1 and the valve body 100, the connection part 101 of the valve body 100 is positioned coaxially with respect to the holder 20 attached to the case-side cylindrical part 16, as shown in Fig. 1. In this state, when the valve drive device 1 and the valve body 100 are brought closer to each other in the axial direction, the driven member 102, which is located at the center of the connection part 101, can be connected to the output shaft 5, as shown in Fig. 2.

[0026] A shaft hole 7 into which the tip of the driven member 102 fits is opened in the tip surface of the output shaft 5. As shown in FIGS. 2 and 4 , the shaft hole 7 has a serration portion 71 with serrations formed on the inner circumferential surface, and a D-cut portion 72 provided on the other axial side L2 of the serration portion 71. The D-cut portion 72 has a D-cut cross section when cut along a plane perpendicular to the axial direction. When connecting the driven member 102 and the output shaft 5, the tip of the driven member 102 is fitted into the serration portion 71 and the D-cut portion 72.

[0027] As shown in FIG. 3, the tip surface of one axial side L1 of the holder 20 is a mounting surface 25 perpendicular to the axial direction. The holder 20 has two mating protrusions 26 protruding from the mounting surface 25. These two mating protrusions 26 are fitted into mating holes 105 (see FIG. 2) that open on an end surface 104 of the connecting portion 101. The mating protrusions 26 and the mating holes 105 fit together to position the connecting portion 101 circumferentially relative to the holder 20. As described above, the holder 20 is positioned circumferentially relative to the case-side cylindrical portion 16 by fitting the notch 24 into the anti-rotation protrusion 18. Therefore, when the mating protrusions 26 are fitted into the mating hole 105, the connecting portion 101 and the case 10 of the valve drive device 1 are positioned circumferentially around the rotation axis L via the holder 20.

[0028] The output shaft 5 is positioned at the origin position in the rotational direction by utilizing an origin alignment positioning feature (not shown) provided inside the second case 12. When connecting the valve drive device 1 to the valve body 100, the output shaft 5 is aligned with the origin position, and the driven member 102 is connected to the output shaft 5 aligned with the origin position. Thereafter, the fitting protrusion 26 of the holder 20 is fitted into the fitting hole 105 of the connection part 101, thereby positioning the holder 20 and the connection part 101 in the circumferential direction.

[0029] A sheet-like sealing material 8, such as a rubber sheet, is arranged on mounting surface 25 of holder 20. When fitting protrusion 26 is fitted into fitting hole 105, end surface 104 of connection portion 101 abuts against sealing material 8 arranged on mounting surface 25. After that, threaded portion 31 of fastening member 30 is screwed into threaded portion 103 provided on the outer peripheral surface of connection portion 101. Small diameter portion 32 of fastening member 30 abuts against flange 22 of holder 20, and fastening member 30 is tightened and fixed until sealing material 8 is crushed. As a result, the gap between mounting surface 25 and end surface 104 is sealed by sealing material 8, preventing water from entering through the connection point between holder 20 and connection portion 101.

[0030] (welded structure) 6 is an exploded cross-sectional view showing a welding recess 91 of the holder 20 and a welding protrusion 92 of the case side cylindrical portion 16. The valve drive device 1 has a welding portion 9 formed by welding the case side cylindrical portion 16 and the holder 20 together over the entire circumference. As shown in FIG. 2, the welding portion 9 is provided between the inner surface of an annular recess 23 provided in the holder 20 and the surface of the case side cylindrical portion 16 facing the inner surface of the annular recess 23. The welding portion 9 is formed by ultrasonically welding a welding protrusion 92 provided on the surface of the case side cylindrical portion 16 to a welding recess 91 provided on the inner surface of the annular recess 23.

[0031] As shown in FIG. 6 , the annular recess 23 includes an annular surface 231 facing the other axial side L2 and a cylindrical surface 232 extending from the outer circumferential edge of the annular surface 231 toward the other axial side L2. The annular surface 231 faces the tip surface 19 of the case-side cylindrical portion 16. The cylindrical surface 232 surrounds the outer periphery of the case-side cylindrical portion 16. The welding recess 91 is a welding groove extending circumferentially along the outer circumferential edge of the annular surface 231. The welding recess 91 is a groove with a rectangular cross section recessed toward one axial side L1. As shown in FIG. 6 , a side surface 93 on the outer periphery of the welding recess 91 includes a protrusion 94 that protrudes inward from the cylindrical surface 232. In this embodiment, the entire outer periphery of the side surface 93 on the outer periphery of the welding recess 91 forms the protrusion 94, which is located more inward than the cylindrical surface 232.

[0032] 3 and 6, the welding protrusion 92 is a welding rib that protrudes from the tip end surface 19 of the case side cylindrical portion 16 to one side L1 in the axial direction. The welding protrusion 92 extends in the circumferential direction along the outer peripheral edge of the tip end surface 19 of the case side cylindrical portion 16. The welding recess 91 and the welding protrusion 92 are both formed in an annular shape over the entire circumference.

[0033] FIG. 7 is an enlarged cross-sectional view of the welded portion 9. The shape indicated by the dashed line D in FIG. 7 is the shape of the welded protrusion 92 before it is crushed by welding. The welded recess 91 and the welded protrusion 92 are welded by ultrasonic welding after the case side cylindrical portion 16 and the holder 20 are assembled. As a result, the tip of the welded protrusion 92 is crushed and welded to the bottom surface of the welded recess 91. In addition, in this embodiment, a side surface 93 on the outer periphery of the welded recess 91 protrudes toward the inner periphery. Therefore, the outer periphery of the welded protrusion 92 is crushed and welded to the side surface 93. By welding the holder 20 and the case side cylindrical portion 16 over the entire circumference, water is prevented from entering through the gap between the holder 20 and the case side cylindrical portion 16.

[0034] (Action and effect) As described above, the valve drive device 1 of this embodiment is connected to the connection portion 101 of the valve body 100 via the fastening member 30 having the threaded portion 31 formed on its inner circumferential surface. The valve drive device 1 includes the motor 2, the output shaft 5 to which rotation of the motor 2 is transmitted, the case 10 that houses the motor 2 and the output shaft 5, the holder 20 fixed to the case 10, and the fastening member 30 attached to the outer periphery of the holder 20. The case 10 includes a flat portion 15 having an opening 17 formed at a position overlapping with the output shaft 5 when viewed in the axial direction along the rotation axis L of the output shaft 5, and a case-side cylindrical portion 16 that protrudes from the flat portion 15 to one side L1 in the axial direction and surrounds the opening 17. The holder 20 includes a holder-side cylindrical portion 21 into which the case-side cylindrical portion 16 fits, and a flange portion 22 that protrudes outer circumferentially from the holder-side cylindrical portion 21. The fastening member 30 has a small diameter portion 32 that protrudes more inward than the threaded portion 31. The fastening member 30 and the holder 20 are assembled such that the holder-side cylindrical portion 21 is passed through the inside of the small diameter portion 32 and the small diameter portion 32 is disposed between the flat portion 15 and the flange portion 22. The holder-side cylindrical portion 21 and the case-side cylindrical portion 16 are welded via a welding portion 9 that extends circumferentially of the holder-side cylindrical portion 21 and the case-side cylindrical portion 16. The holder-side cylindrical portion 21 has a notch portion 24 in which a portion of the holder-side cylindrical portion 21 is cut out in the circumferential direction, and the case-side cylindrical portion 16 has a rotation-preventing protrusion 18 that fits into the notch portion 24. The notch portion 24 has a pair of side portions 241, 242 that face each other in the circumferential direction, and an arc portion 243 that connects the pair of side portions 241, 242.

[0035] In this embodiment, a holder 20, which is a separate component from the case 10 of the valve drive device 1, is required to connect the valve drive device 1 and the valve body 100 using a fastening member 30 having a threaded portion 31 formed on its inner circumferential surface. The holder 20 has a notched portion 24 cut out in a circumferential direction, which prevents rotation of the holder 20 relative to the case-side cylindrical portion 16 when assembled to the case 10. The notched portion 24 has a shape in which a pair of side portions 241 are connected by an arc portion 243, and is shaped without corners that could be the starting point for cracking of components due to vibrations during ultrasonic welding. Therefore, when forming a weld portion 9 at the connection point between the holder 20 and the case 10 to improve waterproofing, cracking of the holder 20 can be suppressed even when the weld portion 9 is formed by ultrasonic welding.

[0036] In this embodiment, the inner surface of the holder-side cylindrical portion 21 is provided with an annular recess 23 into which the case-side cylindrical portion 16 fits, and the annular recess 23 has an annular surface 231 facing the tip surface 19 of the case-side cylindrical portion 16. A welding recess 91 extending in the circumferential direction is provided on the annular surface 231, and a welding protrusion 92 extending in the circumferential direction is provided on the tip surface 19. The welding protrusion 92 is crushed and welded to the welding recess 91, thereby forming the welding portion 9. In this manner, when the case-side cylindrical portion 16 is fitted to the annular recess 23, the welding protrusion 92 can be fitted to the welding recess 91 at the same time. Furthermore, the welding portion 9 can be provided around the entire circumference between the holder-side cylindrical portion 21 and the case-side cylindrical portion 16.

[0037] In this embodiment, the tip of the welding protrusion 92 is crushed and welded to the bottom surface of the welding recess 91, and the outer periphery of the welding protrusion 92 is crushed and welded to the side surface 93 of the welding recess 91. In this way, by welding not only the bottom surface of the welding recess 91 but also the side surface 93, the welding range is wide, thereby improving waterproofness.

[0038] In this embodiment, the annular recess 23 has a cylindrical surface 232 that surrounds the outer periphery of the case-side cylindrical portion 16. The welding recess 91 is an annular welding groove provided on the outer periphery of the annular surface 231. The welding protrusion 92 is an annular welding rib provided on the outer periphery of the tip surface. A side surface 93 on the outer periphery of the welding groove has a protrusion 94 that protrudes inward from the cylindrical surface 232, and the outer periphery of the welding rib is welded to the protrusion 94. In this manner, the side surface of the welding rib and the protrusion 94 are welded to each other. Therefore, the welding range can be expanded.

[0039] In this embodiment, the anti-rotation protrusion 18 contacts each of the pair of side surface portions 241, 242 in the circumferential direction, and therefore the holder 20 can be positioned in the circumferential direction. On the other hand, a gap is formed between the anti-rotation protrusion 18 and the arc portion 243. The upper end surface of the anti-rotation protrusion 18 is not used for positioning, and does not need to have a shape that contacts the arc portion 243. This makes it possible to avoid the shape of the anti-rotation protrusion 18 becoming complicated.

[0040] In this embodiment, the holder 20 has a mounting surface 25 that abuts against the end face 104 of the connection part 101 via the sealant 8, and a fitting protrusion 26 that protrudes from the mounting surface 25. The fitting protrusion 26 fits into a fitting hole 105 that opens in the end face 104 of the connection part 101. This allows the fastening member 30 to be tightened until the sealant 8 is crushed between the end face 104 of the connection part 101 and the mounting surface 25 of the holder 20, thereby improving waterproofing. Furthermore, because the connection part 101 and the holder 20 are positioned circumferentially, the valve body 100 and the case 10 can be connected while being positioned circumferentially via the holder 20.

[0041] In this embodiment, the output shaft 5 has a shaft hole 7 that opens to the end face on one side L1 in the axial direction, and the shaft hole 7 has a D-cut shape on the inner circumferential surface. Therefore, the tip of the driven member 102 can be fitted into the D-cut shape, so that the rotation of the output shaft 5 can be transmitted to the driven member 102.

[0042] (Other embodiments) (1) The arrangement of the welded portion 9 may be in a different position than that of the above configuration. Also, the arrangement of the welded recess 91 and the welded protrusion 92 may be reversed from that of the above configuration. That is, a welded recess 91 extending in the circumferential direction of the holder-side cylindrical portion 21 and the case-side cylindrical portion 16 may be provided on the inner surface of the holder-side cylindrical portion 21 and on the surface of the case-side cylindrical portion 16 facing the inner surface of the holder-side cylindrical portion 21, while a welded protrusion 92 extending in the circumferential direction may be provided on the other inner surface of the holder-side cylindrical portion 21 and the surface of the case-side cylindrical portion 16.

[0043] For example, a welded recess 91 can be provided on the tip surface 19 of the case-side cylindrical portion 16, and a welded projection 92 can be provided on the inner surface of the annular recess 23 in the holder-side cylindrical portion 21. Alternatively, the welded projection 92 or welded recess 91 may be provided on the inner periphery of the tip surface 19 instead of the outer periphery, and the welded recess 91 or welded projection 92 may be provided on the inner periphery of the annular surface 231 instead of the outer periphery.

[0044] Furthermore, in this embodiment, both the tip and outer circumference of the welded projection 92 are crushed and welded to the welded recess 91. However, it is sufficient if at least one of the tip and outer circumference of the welded projection 92 is welded. For example, if no projection 94 is provided on the side surface 93 of the welded recess 91, the outer circumference of the welded projection 92 does not interfere with the side surface of the welded recess 91. Therefore, it does not get crushed during welding, and the welded projection 92 is not welded to the side surface 93.

[0045] (summary) A summary of this disclosure is provided below. (1) A valve drive device connected to the connection part of the valve body via a fastening member having a threaded portion formed on its inner circumferential surface, a motor; an output shaft to which rotation of the motor is transmitted; a case that houses the motor and the output shaft; a holder that is fixed to the case; and the fastening member that is attached to an outer periphery of the holder, the case includes a flat portion having an opening at a position overlapping with the output shaft when viewed in an axial direction along the rotation axis of the output shaft, and a case-side cylindrical portion that protrudes from the flat portion to one side in the axial direction and surrounds the opening, The holder comprises a holder-side cylindrical portion into which the case-side cylindrical portion fits inward, and a flange portion protruding outward from the holder-side cylindrical portion. the fastening member includes a small diameter portion that protrudes radially inward beyond the thread portion, the holder-side cylindrical portion is passed through the inside of the small diameter portion, and the small diameter portion is disposed between the flat portion and the flange portion, The holder-side cylindrical portion and the case-side cylindrical portion are welded together via welding portions extending in the circumferential direction of the holder-side cylindrical portion and the case-side cylindrical portion. The holder-side cylindrical portion is provided with a notch formed by cutting out a part of the circumferential direction, and the case-side cylindrical portion is provided with a rotation-preventing projection that fits into the notch. The valve drive device is characterized in that the notch portion comprises a pair of side portions facing each other in the circumferential direction and an arc portion connecting the pair of side portions.

[0046] (2) an annular recess into which the case-side cylindrical portion is fitted is provided on an inner surface of the holder-side cylindrical portion, the annular recess having an annular surface facing a tip end surface of the case-side cylindrical portion; A welding recess extending in the circumferential direction is provided on one of the tip surface and the annular surface. A welding projection extending in the circumferential direction is provided on the other end surface and the annular surface. The valve drive device according to (1) above, characterized in that the welding protrusion is crushed and welded to the welding recess, thereby forming the welding portion.

[0047] (3) The valve drive device described in (2) above, wherein the tip of the welding protrusion is crushed and welded to the bottom surface of the welding recess, and the outer periphery of the welding protrusion is crushed and welded to the side surface of the welding recess.

[0048] (4) the annular recess has a cylindrical surface surrounding the outer periphery of the case-side cylindrical portion, the welding recess is an annular welding groove provided on an outer peripheral edge of the annular surface, the welding protrusion is an annular welding rib provided on the outer circumferential edge of the tip surface, The valve drive device according to (2) or (3) above, characterized in that the outer peripheral side surface of the welding groove has a protrusion that protrudes inward from the cylindrical surface, and the outer peripheral portion of the welding rib is welded to the protrusion.

[0049] (5) The valve drive device according to any one of (1) to (4) above, wherein the anti-rotation protrusion contacts each of the pair of side surfaces in the circumferential direction and is fitted into a position where a gap is formed between the anti-rotation protrusion and the arc portion.

[0050] (6) the holder includes a mounting surface that abuts against an end surface of the connection portion via a sealant, and a fitting protrusion that protrudes from the mounting surface; The valve drive device according to any one of (1) to (5) above, wherein the fitting protrusion is fitted into a fitting hole opening in the end surface.

[0051] (7) the output shaft has a shaft hole that opens to one end surface in the axial direction, The valve drive device according to any one of (1) to (6) above, wherein the shaft hole has an inner peripheral surface formed in a D-cut shape. [Explanation of symbols]

[0052] 1... valve drive device, 2... motor, 3... output member, 4... gear train, 5... output shaft, 6... gear portion, 7... shaft hole, 8... seal material, 9... welded portion, 10... case, 11... first case, 12... second case, 13... screw, 14... O-ring, 15... flat portion, 16... case side cylindrical portion, 17... opening, 18... rotation stopper protrusion, 19... tip surface, 20... holder, 21... holder side cylindrical portion, 22... flange portion, 23... annular recess, 24... notch portion, 25... mounting surface, 26... fitting Convex portion, 30...fastening member, 31...threaded portion, 32...small diameter portion, 71...serration portion, 72...D-cut portion, 91...welding recess, 92...welding protrusion, 93...side surface, 94...protrusion, 100...valve body, 101...connection portion, 102...driven member, 103...threaded portion, 104...end face, 105...fitting hole, 231...annular surface, 232...cylindrical surface, 241...side surface portion, 243...arc portion, L...rotation axis, L1...one side in the axial direction, L2...other side in the axial direction, S...gap

Claims

1. A valve drive device connected to a connection portion of a valve body via a fastening member having a threaded portion formed on an inner circumferential surface, a motor, an output shaft to which rotation of the motor is transmitted, a case that houses the motor and the output shaft, a holder that is fixed to the case, and the fastening member that is attached to an outer periphery of the holder, the case includes a flat portion having an opening at a position overlapping with the output shaft when viewed in an axial direction along the rotation axis of the output shaft, and a case-side cylindrical portion that protrudes from the flat portion to one side in the axial direction and surrounds the opening, the holder includes a holder-side cylindrical portion into which the case-side cylindrical portion fits, and a flange portion that protrudes from the holder-side cylindrical portion toward an outer periphery thereof, the fastening member includes a small diameter portion that protrudes radially inward beyond the thread portion, the holder-side cylindrical portion is passed through the inside of the small diameter portion, and the small diameter portion is disposed between the flat portion and the flange portion, the holder-side cylindrical portion and the case-side cylindrical portion are welded to each other via a welding portion extending in a circumferential direction of the holder-side cylindrical portion and the case-side cylindrical portion, the holder-side cylindrical portion has a notched portion formed by cutting out a part of the holder-side cylindrical portion in the circumferential direction, and the case-side cylindrical portion has a rotation-preventing protrusion that fits into the notched portion, The valve drive device, wherein the notch portion includes a pair of side surfaces facing each other in the circumferential direction and an arc portion connecting the pair of side surfaces.

2. an annular recess into which the case-side cylindrical portion is fitted is provided on an inner surface of the holder-side cylindrical portion, the annular recess having an annular surface facing a tip end surface of the case-side cylindrical portion; a welding recess extending in the circumferential direction is provided on one of the tip surface and the annular surface, a welding protrusion extending in the circumferential direction is provided on the other of the tip surface and the annular surface, 2. The valve drive device according to claim 1, wherein the welding protrusion is crushed and welded to the welding recess, thereby forming the welding portion.

3. 3. The valve drive device according to claim 2, wherein a tip of the welding protrusion is crushed and welded to the bottom surface of the welding recess, and an outer periphery of the welding protrusion is crushed and welded to the side surface of the welding recess.

4. the annular recess has a cylindrical surface surrounding the outer periphery of the case-side cylindrical portion, the welding recess is an annular welding groove provided on an outer peripheral edge of the annular surface, the welding protrusion is an annular welding rib provided on the outer circumferential edge of the tip surface, 4. The valve drive device according to claim 3, wherein an outer peripheral side surface of the welding groove has a protrusion that protrudes inward from the cylindrical surface, and an outer peripheral portion of the welding rib is welded to the protrusion.

5. 2. The valve drive device according to claim 1, wherein the anti-rotation protrusion contacts each of the pair of side surfaces in the circumferential direction, and a gap is formed between the anti-rotation protrusion and the arc portion in the axial direction.

6. the holder includes a mounting surface that abuts against an end surface of the connection portion via a sealant, and a fitting protrusion that protrudes from the mounting surface; 2. The valve drive device according to claim 1, wherein the fitting protrusion is fitted into a fitting hole that opens in the end surface.

7. the output shaft has a shaft hole that opens to one end surface in the axial direction, 2. The shaft hole according to claim 1, wherein the inner peripheral surface of the shaft hole is provided with a D-cut shape. Valve drive mechanism.

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