Connection device and method for producing connection device

Abstract

To reduce loss of transmission of relative rotation between two shafts to a joint.SOLUTION: A connection device 10 for connecting a drive shaft 80 to a valve shaft 90 includes a joint 40, the joint 40 having: a recess 41A in which a lower part of a fixing member 20 fixed to the drive shaft 80 is inserted from above; a recess 41B in which an upper part of the fixing member 30 fixed to the valve shaft 90 is inserted from below; and a through hole 41C in communication with the recess 41A and the recess 41B. Further, a first member 51 and a second part 52 of a cramp member 50 hold the fixing member 20 and the fixing member 30 therebetween from a vertical direction to press the fixing member 20 and the fixing member 30 against the joint 40, and cause the joint 40 to twist when relative rotation occurs between the drive shaft 80 and the valve shaft 90. Further, a strain gauge 70 is fixed to the joint 40 and is configured to detect twisting of the joint 40.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a coupling device for two shafts and to a method for manufacturing the coupling device. [Background technology]

[0002] Patent Document 1 discloses a coupling device that includes a joint (coupling) that connects two shafts, such as a rotating shaft of an actuator and a valve shaft to which a valve body or the like is connected, and a strain gauge provided in the joint to detect the relative rotation of the two shafts. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-96285 Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 does not disclose details of the connection manner of the connection device, and depending on the connection manner, rattle may occur between the shaft and the joint, causing a loss in the transmission of relative rotation between the two shafts to the joint.

[0005] An object of the present invention is to reduce the transmission loss of the relative rotation between two shafts to a joint. [Means for solving the problem]

[0006] The connecting device of the present invention comprises a first fixing member fixed to the lower end of a first shaft when the rotation axis direction is the up-down direction, a second fixing member fixed to the upper end of a second shaft arranged below the first shaft and coaxial with the first shaft, a joint having a first recess into which the lower part of the first fixing member is inserted from above and a second recess into which the upper part of the second fixing member is inserted from below, a clamping member that sandwiches the first fixing member and the second fixing member from above and above, pressing the first fixing member and the second fixing member against the joint, and twisting the joint when relative rotation occurs between the first shaft and the second shaft, and a strain gauge fixed to the joint and detecting the twisting of the joint.

[0007] A method for manufacturing the connecting device includes a first step of selecting, from a plurality of types of fixing members having different shapes depending on the shapes of the ends of the shafts, a fixing member having a shape corresponding to the shape of the lower end of the first shaft as the first fixing member, and selecting a fixing member having a shape corresponding to the shape of the upper end of the second shaft as the second fixing member; a second step of selecting, from a plurality of types of joints prepared in advance, a joint having a shape matching the first fixing member and the second fixing member selected in the first step; and a third step of assembling the connecting device using the first fixing member, the second fixing member, and the joint selected in the second step. [Effects of the Invention]

[0008] According to the present invention, the transmission loss of the relative rotation between the two shafts to the joint is reduced. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of a coupling device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view of the coupling device of FIG. [Figure 3] FIG. 3 is an exploded perspective view of the coupling device of FIG. [Figure 4] 4 is an exploded perspective view of the coupling device of FIG. 1. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A coupling device according to an embodiment of the present invention will now be described with reference to the drawings.

[0011] 1 to 4, a coupling device 10 according to one embodiment of the present invention is configured to coaxially couple a drive shaft 80, which is rotationally driven by an actuator (not shown), to a valve shaft 90, which is connected to a valve body (not shown). The coupling device 10 transmits the rotation of the drive shaft 80 to the valve shaft 90, causing the drive shaft 80 and the valve shaft 90 to rotate integrally.

[0012] In this specification, the direction of the central axes of the drive shaft 80 and the valve shaft 90, i.e., the direction of the rotation axis C, is defined as the up-down direction, with the drive shaft 80 side defined as the top and the valve shaft 90 side defined as the bottom. In other words, the valve shaft 90 is located below the drive shaft 80. The up-down direction is set for convenience and does not limit the arrangement direction of the coupling device 10. In other words, the up-down direction may differ from the actual top-to-bottom direction.

[0013] The lower end 81 of the drive shaft 80 (the end on the valve shaft 90 side) is formed in a cylindrical shape with a circular cross section and threaded. The upper end 91 of the valve shaft 90 (the end on the drive shaft 80 side) which faces the lower end 81 in the vertical direction is formed in a rectangular shape with a square cross section, in particular in the shape of a square pillar boss protruding from a cylindrical shaft body 92.

[0014] The coupling device 10 includes a fixed member 20, a fixed member 30, a joint 40, a clamp member 50, a strain gauge support plate 60, and a strain gauge 70. The fixed member 20, the fixed member 30, the joint 40, and the clamp member 50 are arranged so that their respective central axes coincide with the rotation axis C of the drive shaft 80 and the valve shaft 90.

[0015] The fixing member 20 is made of metal and ring-shaped, and is fixed to the lower end 81 of the drive shaft 80 so as not to rotate relative to the lower end 81. The fixing member 20 includes ring-shaped nuts 21 and 22 that are threadedly fixed to the lower end 81. The nuts 21 and 22 are threaded onto the lower end 81 of the drive shaft 80 as a double nut. The double nut prevents the nuts 21 and 22 from rotating, making the nuts 21 and 22 non-rotatable relative to the lower end 81. The lower end of the nut 22, located below the nut 21, has a tapered portion 22A that is shaped like a truncated cone that tapers downward with the rotation axis C as its central axis. In Figures 3 and 4, the female threads that are provided on the inner surfaces of the nuts 21 and 22 and that thread onto the lower end 81 of the drive shaft 80 are not shown. The fixing member 20 may be fixed by welding or the like.

[0016] The fixing member 30 is fixed to the upper end 91 of the valve stem 90 so as not to rotate. When viewed from the direction of the rotation axis C, the fixing member 30 includes four blocks 31 to 34 arranged radially at 90-degree intervals from the position of the rotation axis C. As described below, the blocks 31 to 34 are positioned by a joint 40. The positioned blocks 31 to 34 sandwich the angular upper end 91 of the valve stem 90 from two mutually perpendicular directions (radial directions D1 and D2 described below). As a result, the upper end 91 is clamped from four directions by the blocks 31 to 34. This clamping secures the fixing member 30 to the upper end 91. As described in detail below, each of the blocks 31 to 34 has a notch K, which improves the elastic force of the blocks 31 to 34 and thereby improves the clamping force of the upper end 91.

[0017] The fixed member 30 has a tapered portion 30A that tapers upward from the rotation axis C as the central axis. The tapered portion 30A is made up of portions including flat surfaces 31A to 34A of four blocks 31 to 34. The flat surfaces 31A to 34A are inclined downward as they move away from the central axis.

[0018] The joint 40 is formed in a cylindrical shape and configured to connect the drive shaft 80 and the valve shaft 90 via the fixing members 20 and 30. The joint 40 includes a cylindrical joint body 41, reinforcing portions 42 and 43, and protrusions 44 to 47.

[0019] The joint body 41 has a recess 41A at its upper opening and a recess 41B at its lower opening. The joint body 41 further has a through-hole 41C that connects the recess 41A and the recess 41B in the vertical direction.

[0020] The joint body 41 has a tapered surface 41D formed therein that forms a recess 41A. The tapered surface 41D tapers downward with the rotation axis C as its central axis. The tapered portion 22A, which is the lower part of the fixing member 20, is inserted from above into the recess 41A. When the tapered portion 22A is inserted, the side surface of the tapered portion 22A (the surface shaped like a truncated cone) fits into the tapered surface 41D (the tapered portion 22A engages with the tapered surface 41D). As a result, the fixing member 20 and the drive shaft 80 are positioned and supported by the recess 41A (tapered surface 41D).

[0021] The joint body 41 also has a tapered surface 41E therein that forms a recess 41B. The tapered surface 41E is made up of multiple (four in this example) flat surfaces 41EA-41ED that are arranged radially around the rotation axis C (central axis). The tapered surface 41E as a whole tapers upward with the rotation axis C as the central axis. The flat surfaces 41EA-41ED are inclined surfaces that slope downward as they move away from the rotation axis C. When viewed from below in the direction of the rotation axis C, the flat surfaces 41EA-41ED form a cross shape in the recess 41B. The upper portions of the blocks 31-34 of the fixing member 30 are inserted into the recess 41B from below, thereby positioning the blocks 31-34. At this time, the flat surfaces 41EA-41ED mate with the flat surfaces 31A-34A of the blocks 31-34, respectively.

[0022] The reinforcing portions 42 and 43 protrude in the first radial direction D1 from the outer peripheral surface of the joint body 41 and are formed like plates extending in the vertical direction. The reinforcing portions 42 and 43 reinforce the joint 40 and prevent deformation of the joint 40 due to one of the axes 80 and 90 being inclined in the radial direction D1 relative to the other. The reinforcing portions 42 and 43 protrude in opposite directions 180 degrees apart from the rotation axis C.

[0023] The protrusions 44 to 47 protrude in the second radial direction D2 from the outer peripheral surface of the joint body 41. The second radial direction D2 is perpendicular to the first radial direction D1. The protrusions 44 and 45 are spaced apart in the vertical direction, and one of the two strain gauge support plates 60 is attached to each of them. The protrusions 44 and 45 each support both ends of the strain gauge support plate 60, which is long in the vertical direction. The protrusions 46 and 47 protrude on the opposite side of the protrusions 44 and 45 across the rotation axis C, and are spaced apart in the vertical direction, and the remaining one of the two strain gauge support plates 60 is attached to each of them. The protrusions 46 and 47 each support both ends of the strain gauge support plate 60, which is long in the vertical direction.

[0024] Each of the two strain gauge support plates 60 supports a plate-shaped strain gauge 70 (the internal structure is omitted in the cross-sectional view of FIG. 2). The strain gauge support plate 60 is formed of, for example, a metal material. The strain gauge 70 is composed of, for example, any element with an insulating base. The strain gauge 70 may be composed of any element. The strain gauge support plate 60 or the strain gauge 70 is disposed at a position obtained by shifting the reinforcing portion 42 or 43 by 90 degrees around the rotation axis C. Twisting and deformation of the joint 40 (particularly the joint body 41) deforms (distorts) each strain gauge 70 via the strain gauge support plate 60 (and the protrusions 44 to 47). The strain gauge support plate 60 or the strain gauge 70 is oriented such that the in-plane directions are the up-down direction and a direction parallel to a first radial direction D1 that is perpendicular to the protrusion direction of the protrusions 44 to 47. The strain gauge 70 oriented in this manner detects, as strain, the torsion of the joint 40 due to the relative rotation between the drive shaft 80 and the second shaft, and the deformation of the joint 40 when one of the shafts 80 and 90 tilts in the radial direction D1 relative to the other. However, the latter deformation of the joint 40 is suppressed by the reinforcement portions 42 and 43. This allows the strain gauge 70 to accurately detect the torsion of the joint 40 due to the relative rotation between the drive shaft 80 and the second shaft. The strain gauge 70 is insensitive to the deformation of the joint 40 when one of the shafts 80 and 90 tilts in the radial direction D2 relative to the other (deformation of the joint 40 along the second radial direction D2 perpendicular to the first radial direction D1 and along the in-plane direction extending up and down). In other words, the strain gauge 70 does not detect this deformation. For this reason, in this embodiment, a reinforcement portion for suppressing this deformation is unnecessary and not provided. "No deformation is detected" means that the detected value is 0, and also includes the case where the detected value is smaller than a predetermined value and can be ignored. In this embodiment, the strain gauge 70 is provided on the surface of the strain gauge support plate 60 on the rotation axis C side, but it may also be provided on the opposite surface (see the member designated by the symbol 70 in the dashed dotted line in Figure 2).

[0025] The strain detected by the strain gauge 70 is sent to a processing circuit (not shown), which calculates the torque of the shaft 80 or 90 .

[0026] The clamp member 50 sandwiches the fixed member 20 and the fixed member 30 from above and below, and presses the fixed member 20 and the fixed member 30 against the joint 40. This increases the frictional force between the joint 40 and the fixed member 20 and the fixed member 30 fixed to the drive shaft 80 and the valve shaft 90, respectively, and allows the joint 40 to twist without loss when relative rotation occurs between the drive shaft 80 and the valve shaft 90.

[0027] The clamp member 50 comprises a first member 51 positioned above the fixing member 20, a second member 52 positioned below the fixing member 20, and bolts 53 and 54 that fasten the first member 51 and the second member 52 together.

[0028] The first member 51 and the second member 52 extend in the radial direction D2. The bolt 53 passes through a through hole 52A at a first end of the second member 52 and is inserted into a threaded hole 51A at the first end of the first member 51, and is threadedly engaged with the threaded hole 51A (inner threads are not shown in FIGS. 1, 3, and 4). The bolt 54 passes through a through hole 52B at a second end of the second member 52 and is inserted into a threaded hole 51B at the second end of the first member 51, and is threadedly engaged with the threaded hole 51B (inner threads are not shown in FIGS. 1, 3, and 4). The drive shaft 80 passes through a central through hole 51C of the first member 51, and the valve shaft 90 passes through a central through hole 52C of the second member 52.

[0029] The bolts 53 and 54 extend in the vertical direction, and can be rotated to change the distance between the first member 51 and the second member. The worker adjusts the rotation (tightness) of the bolts 53 and 54 to sandwich the fixing members 20 and 30 between the first member 51 and the second member 52.

[0030] By sandwiching the fixing member 20 between the first member 51 and the second member 52, the tapered portion 22A of the fixing member 20 is pressed into the tapered surface 41D of the joint 40. As a result, the tapered surface 41D presses the fixing member 20 (tapered portion 22A) in a direction that reduces the diameter (see arrow R1 in FIG. 2). By reducing the diameter of the fixing member 20, the fixing member 20 tightens the drive shaft 80, and the fixing force of the fixing member 20 to the drive shaft 80 can be increased.

[0031] By sandwiching the first member 51 and the second member 52, the blocks 31-34 (particularly, the tapered portion 30A) of the fixing member 30 are pressed against the flat surfaces 41EA-41ED of the joint 40, respectively. As a result, the flat surfaces 41EA-41ED press the fixing member 30 (the tapered portion 30A) in a direction that reduces the diameter (see arrow R2 in FIG. 2). As a result, the flat surfaces 31A-34A of the blocks 31-34 of the tapered portion 30A are pressed, respectively, narrowing the width of the notch K. Due to an elastic force that tries to return this width to its original state, the blocks 31-34 press the upper end 91 of the valve stem 90 (see arrow R3 in FIG. 2). With the above-mentioned configuration, the amount by which the fixing member 30 clamps the upper end 91 of the valve stem 90 can be increased.

[0032] It is preferable that the degree of engagement of bolt 53 with first member 51 and the degree of engagement of bolt 54 with first member 51 are the same, and that first member 51 and second member 52 are parallel to each other. However, even if they are not parallel, the deformation of joint 40 due to this non-parallelism will be oriented in the same direction as the deformation of joint 40 when one of axes 80 and 90 is tilted in radial direction D2 relative to the other. Since strain gauge 70 is insensitive to such deformation, some difference between the degree of engagement of bolt 53 with first member 51 and the degree of engagement of bolt 54 with first member 51 is permissible.

[0033] In this embodiment, joint 40 includes recess 41A into which the lower portion (tapered portion 22A) of fixed member 20 fixed to drive shaft 80 is inserted from above, recess 41B into which the upper portion (tapered portion 30A) of fixed member 30 is inserted from below, and through-hole 41C communicating with recess 41A and recess 41B. Furthermore, clamp member 50 sandwiches fixed member 20 and fixed member 30 from above and below, pressing fixed member 20 and fixed member 30 against joint 40 (tapered surface 41D, flat surfaces 41EA-41ED), causing joint 40 to twist when relative rotation occurs between drive shaft 80 and valve stem 90. Furthermore, strain gauge 70 is fixed to joint 40 and configured to detect torsion of joint 40. With this configuration, the frictional force between the joint 40 and the fixed member 20 and the fixed member 30 fixed to the drive shaft 80 and the valve shaft 90, respectively, is improved, and when relative rotation occurs between the drive shaft 80 and the valve shaft 90, this rotational force is transmitted to the joint 40 with little transmission loss. As a result, the transmission loss of the relative rotation between the two shafts to the joint is reduced. In this embodiment, the joint 40 is formed in a cylindrical shape by including the recess 41A, the recess 41B, and the through hole 41C, but it may also be formed in a non-cylindrical shape without the through hole 41C.

[0034] The tapered surface 41D forming the recess 41A of the joint 40 has a shape that tapers downward with the rotation axis C as the central axis, and is formed so that when the fixed member 20 is pressed against the joint 40 by the clamp member 50, the fixed member 20 is pressed in the direction of the central axis, thereby reducing the diameter of the fixed member 20. This strengthens the fixation of the fixed member 20 to the drive shaft 80, and prevents the drive shaft 80 from coming off the fixed member 20.

[0035] The tapered surface 41E forming the recess 41B of the joint 40 has a shape that tapers upward with the rotation axis C as the central axis, and is formed so as to press the fixing member 30 in the direction of the central axis when the fixing member 30 is pressed against the joint 40 by the clamp member 50, thereby reducing the diameter of the fixing member 30. This strengthens the fixation of the fixing member 30 to the valve stem 90, and prevents the valve stem 90 from coming off the fixing member 30.

[0036] The fixed member 20 is ring-shaped with the drive shaft 80 passing through its center, and has a tapered portion 22A at its lower end that tapers downward with the rotation axis as its central axis and engages with the tapered surface 41D, and the tapered surface 41D presses against the tapered portion 22A, thereby ensuring smooth transmission of the pressing force.

[0037] The fixing member 30 has a tapered portion 30A at its upper end that tapers upward with the rotation axis as its central axis, the tapered portion 30A has a plurality of flat surfaces 31A to 34A, and the tapered surface 41E has a plurality of flat surfaces 41EA to 41ED that press against the plurality of flat surfaces 31A to 34A, respectively.

[0038] The joint 40 includes a cylindrical joint body 41 and plate-like reinforcing portions 42 and 43 that protrude from the joint body 41 along the first radial direction D1 and extend in the up-down direction to reinforce the joint 40. The strain gauge 70 is disposed at a rotation angle of 90 degrees from the reinforcing portion 43 of the joint body 41 when viewed from the up-down direction, and is configured in a plate shape with an in-plane direction parallel to the first radial direction and the up-down direction. This suppresses deformation of the joint 40 in the direction in which the strain gauge 70 is sensitive (deformation of the joint 40 caused by inclination of one of the drive shaft 80 and the valve stem 90 along the first radial direction), thereby suppressing detection of the deformation by the strain gauge 70 as noise, etc.

[0039] The clamp member 50 includes a first member 51 and a second member 52 that sandwich the fixing members 20 and 30 from above and below, and two bolts 53 and 54 that penetrate the second member 52 and screw into the first member 51 to adjust the distance between the first member 51 and the second member 52. The two bolts 53 and 54 screw into the first member 51 at both ends in a second radial direction D2 that is perpendicular to the first radial direction D1. The bolts may also penetrate the first member 51 and screw into the second member 52. With this structure, deformation of the joint 40 when the first member 51 and the second member 52 are not parallel is in a direction that is insensitive to the strain gauge 70 (the same deformation as the deformation of the joint 40 caused by inclination of one of the drive shaft 80 and the valve stem 90 along the second radial direction). This eliminates the need to precisely adjust the degree of screwing of the bolts 53 and 54, improving convenience for the operator.

[0040] The two shafts to be connected by the connecting device 10 may be any shafts. The shape of the shafts is not limited to the above. Other examples of the shaft ends include polygonal prisms other than square prisms, and D-cut ends. The shapes of the fixing members 20 and 30 are changed depending on the shapes of the shafts to be connected.

[0041] The coupling device 10 may be used in place of an existing coupling device that already connects two shafts, such as a drive shaft and a valve shaft. In such cases, the following manufacturing method is used. This allows for the retrofitting of a torque detection function using a strain gauge to an existing field device, for example, even when the shape of the shaft varies depending on the site. (1st step) From multiple types of fixing members (prepared in advance by the manufacturer of the connecting device) having different shapes depending on the shape of the end (upper or lower end) of the shaft, a fixing member having a shape corresponding to the shape of the lower end of the first shaft of the shafts to be connected is selected as fixing member 20, and a fixing member having a shape corresponding to the shape of the upper end of the second shaft is selected as fixing member 30. (Second step) From a plurality of types of joints 40 prepared in advance, joints 40 having shapes that match the fixing members 20 and 30 selected in the first step are selected. (Third Step) The above-mentioned connecting device is assembled using the fixing member 20, fixing member 30, and joint 40 selected in the second step.

[0042] Although the present invention has been described above with reference to the embodiments and modifications, the present invention is not limited to the above embodiments and modifications. For example, the present invention includes various modifications to the above embodiments and modifications that can be understood by a person skilled in the art within the scope of the technical concept of the present invention. The configurations listed in the above embodiments and modifications can be combined as appropriate within a range that does not cause inconsistencies.

[0043] The configurations disclosed in this specification are described below. (Appendix 1) a first fixed member fixed to a lower end of the first shaft when the rotation axis direction is the up-down direction; a second fixing member fixed to an upper end of a second shaft disposed below the first shaft and coaxial with the first shaft; a joint including a first recess into which a lower portion of the first fixing member is inserted from above, and a second recess into which an upper portion of the second fixing member is inserted from below; a clamp member that sandwiches the first fixing member and the second fixing member from above and below to press the first fixing member and the second fixing member against the joint, and twists the joint when relative rotation occurs between the first shaft and the second shaft; a strain gauge fixed to the joint and detecting a twist of the joint; A coupling device comprising: (Appendix 2) the joint has a first tapered surface that forms the first recess; The first tapered surface is The rotary shaft is a central axis, and the shape tapers downward, When the first fixing member is pressed against the joint by the clamp member, the first fixing member is pressed in the direction of the central axis, thereby reducing the diameter of the first fixing member. 10. The coupling device of claim 1. (Appendix 3) the joint has a second tapered surface that forms the second recess; The second tapered surface is The rotary shaft is a central axis, and the shape tapers upward, When the second fixing member is pressed against the joint by the clamp member, the second fixing member is pressed in the direction of the central axis, thereby reducing the diameter of the first fixing member. 10. A coupling device as described in Appendix 2. (Appendix 4) the first fixing member is ring-shaped with the first axis passing through its center, and includes a first tapered portion at its lower end that tapers downward with the rotation shaft as its central axis and engages with the first tapered surface; the first tapered surface presses the first tapered portion; 4. A coupling device according to claim 2 or 3. (Appendix 5) the second fixing member has a second tapered portion at its upper end, the second tapered portion tapering upward with the rotation shaft as its central axis, the second tapered portion has a plurality of flat surfaces; the second tapered surface includes a plurality of flat surfaces that press against the plurality of flat surfaces, respectively; 4. A coupling device according to claim 2 or 3. (Appendix 6) the joint includes a joint body having the first recess and the second recess, and a plate-shaped reinforcing part that protrudes from the joint body along a first radial direction and extends in an up-down direction to reinforce the joint, The strain gauge is disposed at a position at a rotation angle of 90 degrees from the reinforcing portion of the joint body when viewed from the up-down direction, and is configured in a plate shape with a direction parallel to the first radial direction and the up-down direction as in-plane directions. 6. A coupling device according to any one of appendices 1 to 5. (Appendix 7) the clamp member includes a first member and a second member that sandwich the first fixing member and the second fixing member from above and below, and two bolts that pass through one of the first member and the second member and screw into the other to adjust the distance between the first member and the second member, The two bolts are screwed into the other bolt at both ends in a second radial direction perpendicular to the first radial direction of the first member and the second member. 10. A coupling device as described in Appendix 6. (Appendix 8) One of the first shaft and the second shaft is a drive shaft that is rotationally driven by an actuator, and the other is a valve shaft that is connected to a valve body. A coupling device according to any one of appendices 1 to 7. (Appendix 9) A method for manufacturing a coupling device according to any one of appendices 1 to 8, a first step of selecting, from a plurality of types of fixing members having different shapes according to the shapes of the ends of the shafts, a fixing member having a shape corresponding to the shape of the lower end of the first shaft as the first fixing member, and selecting a fixing member having a shape corresponding to the shape of the upper end of the second shaft as the second fixing member; a second step of selecting a joint having a shape that matches the first fixing member and the second fixing member selected in the first step from a plurality of types of joints prepared in advance; a third step of assembling the connecting device using the first fixing member, the second fixing member, and the joint selected in the second step; A method for manufacturing a coupling device comprising: [Explanation of symbols]

[0044] 10...connecting device, 20...fixing member, 21, 22...nut, 22A...tapered portion, 30...fixing member, 30A...tapered portion, 31 to 34...block, 31A to 34A...flat surface, 40...joint, 41...joint body, 41A, 41B...recess, 41C...through hole, 41D...tapered surface, 41E...tapered surface, 41EA to 41ED...flat surface, 42, 43...reinforcing portion, 44 47...protrusion, 50...clamping member, 51...first member, 51A, 51B...screw hole, 51C...through hole, 52...second member, 52A, 52B...through hole, 52C...through hole, 53, 54...bolt, 60...gauge support plate, 70...strain gauge, 80...drive shaft, 81...lower end, 90...valve shaft, 91...upper end, 92...shaft body, C...rotating shaft, D1, D2...radial direction, R1 to R3...arrows.

Claims

1. a first fixed member fixed to a lower end of the first shaft when the rotation axis direction is the up-down direction; a second fixing member fixed to an upper end of a second shaft disposed below the first shaft and coaxial with the first shaft; a joint including a first recess into which a lower portion of the first fixing member is inserted from above, and a second recess into which an upper portion of the second fixing member is inserted from below; a clamp member that sandwiches the first fixing member and the second fixing member from above and below to press the first fixing member and the second fixing member against the joint, thereby twisting the joint when relative rotation occurs between the first shaft and the second shaft; a strain gauge fixed to the joint and detecting a twist of the joint; A coupling device comprising:

2. the joint has a first tapered surface that defines the first recess; The first tapered surface is The rotary shaft is a central axis, and the shape tapers downward, When the clamp member presses the first fixing member against the joint, the clamp member presses the first fixing member in the direction of the central axis, thereby reducing the diameter of the first fixing member. The coupling device of claim 1 .

3. the joint has a second tapered surface that forms the second recess; The second tapered surface is The rotary shaft is a central axis, and the shape tapers upward, When the second fixing member is pressed against the joint by the clamp member, the second fixing member is pressed in the direction of the central axis, thereby reducing the diameter of the first fixing member. The coupling device of claim 2 .

4. the first fixing member has a ring shape with the first axis passing through its center, and includes a first tapered portion at its lower end, tapering downward with the rotation axis as its central axis, and engaging with the first tapered surface; the first tapered surface presses the first tapered portion; A coupling device according to claim 2 or 3.

5. the second fixing member has a second tapered portion at its upper end, the second tapered portion being tapered upward with the rotation shaft as its central axis, the second tapered portion includes a plurality of flat surfaces; the second tapered surface includes a plurality of flat surfaces that press against the plurality of flat surfaces, respectively; A coupling device according to claim 2 or 3.

6. the joint includes a joint body having the first recess and the second recess, and a plate-shaped reinforcing part that protrudes from the joint body along a first radial direction and extends in an up-down direction to reinforce the joint, The strain gauge is disposed at a position at a rotation angle of 90 degrees from the reinforcing portion of the joint body when viewed from the up-down direction, and is configured in a plate shape with an in-plane direction parallel to the first radial direction and the up-down direction. The coupling device of claim 1 .

7. the clamp member includes a first member and a second member that sandwich the first fixing member and the second fixing member from above and below, and two bolts that pass through one of the first member and the second member and screw into the other to adjust the distance between the first member and the second member, The two bolts are screwed into the other bolt at both ends in a second radial direction perpendicular to the first radial direction of the first member and the second member.

7. The coupling device of claim 6.

8. One of the first shaft and the second shaft is a drive shaft that is rotationally driven by an actuator, and the other is a valve shaft that is connected to a valve body. The coupling device of claim 1 .

9. A method for manufacturing the coupling device according to claim 1, comprising the steps of: a first step of selecting, from a plurality of types of fixing members having different shapes according to the shapes of the ends of the shafts, a fixing member having a shape corresponding to the shape of the lower end of the first shaft as the first fixing member, and selecting a fixing member having a shape corresponding to the shape of the upper end of the second shaft as the second fixing member; a second step of selecting a joint having a shape that matches the first fixing member and the second fixing member selected in the first step from a plurality of types of joints prepared in advance; a third step of assembling the connecting device using the first fixing member, the second fixing member, and the joint selected in the second step; A method for manufacturing a coupling device comprising:

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