Coupling for position detector

Abstract

Position detector coupling for connecting mounting sections of an object to be detected and mounting sections of a position detector, comprising: a shaped, ring-shaped thin plate; a first and a second thick plate; and a third and a fourth thick plate machined by tapping, wherein the thin plate is provided with a first bent portion and a second bent portion arranged as a pair in positions opposite to each other with respect to a center of the ring shape, and a third bent portion and a fourth bent portion arranged as a pair in positions opposite to each other with respect to the center the first bent portion and the second bent portion are provided with forked support members spaced apart in respective tangential circumferential directions, and the third bent portion and the fourth bent portion are provided with forked support members spaced apart in respective tangential circumferential directions, respective forked support parts of the first bent portion and the second bent portion are fixed to the fixing portions of the position detector, the first thick plate and the second thick plate are provided with forked support members spaced apart in respective tangential circumferential directions, the third thick plate machined by tapping is screwed to the forked support parts of the third bent section to insert the forked support parts of the first thick plate, and the fourth thick plate machined by tapping is screwed to the forked support parts of the fourth bent section to insert the forked support parts of the second thick plate, and the first thick plate and the second thick plate have mounting holes arranged for connection to the ring screwed to the object to be detected.

Description

[0001] This application claims priority to Japanese Patent Application No. 2019-110849, filed on June 14, 2019. TECHNICAL FIELD

[0002] The present disclosure relates to a coupling incorporated in a position detector used for a machine tool or the like. BACKGROUND

[0003] A coupling for a position detector (hereinafter referred to as a "position detector coupling") is used to connect the mounting portions of a motor or the like to be detected and the mounting portions of the position detector. Functions of the position detector coupling include absorbing the runout of a rotating shaft to reduce errors that may occur, and absorbing vibration, shock, and the like transmitted from the rotating shaft to protect the bearings of the position detector and a processing circuit board or the like. To absorb the above-described vibration and shock, elasticity is required. Meanwhile, to eliminate detection errors and also increase the reference frequency, high rigidity in the rotation direction is required.

[0004] Fig. 3 is a perspective view of a conventional coupling.

[0005] The illustrated conventional coupling is configured by a single molded plate and two blocks, with two support members 120 and 130 and two opposing support members 320 and 330 being screwed to mounting portions of a position detector, and two support members 220 and 230 and two opposing support members 420 and 430 being screwed to two blocks 900 and 100, respectively. The two blocks 900 and 100 are screwed to ring holes 600 and 800 on one mounting side of an object to be detected. Holes 500 and 700 are screwed to mounting portions of the object to be detected.

[0006] The conventional coupling includes bent portions 110 and 310 arranged in positions opposite to each other with a coupling center therebetween, and also includes bent portions 210 and 410 arranged similarly. The two support members 120 and 130 are arranged in positions spaced from the corresponding bent portion in the tangential circumferential direction. The support members 220 and 230, the support members 320 and 330, and the support members 420 and 430 are arranged similarly. Therefore, when a rotational force acts about the z-axis, respective pairs of the support members 120, 130, 220, 230, 320, 330, 420, and 430 support the bent portions 110, 210, 310, and 410 primarily by the force of the plate in the compressive or tensile direction. Therefore, high rigidity can be achieved.Furthermore, respective pairs of support members 120, 130, 220, 230, 320, 330, 420, and 430 are arranged at intervals with respect to the bent portions 110, 210, 310, and 410. Consequently, when displacement occurs in the x-direction, the bent portions 110 and 310 are displaced relative to the support members 120, 130, 320, and 330 in the plate thickness direction. When displacement occurs in the y-direction, the bent portions 210 and 410 are displaced relative to the support members 220, 230, 420, and 430 in the plate thickness direction. Therefore, the respective bent portions are elastically supported.

[0007] In addition, since the two blocks 900 and 100 are thick in the z-direction in the circumference of the screw fastening portions, respective support parts 220, 230, 420 and 430 are firmly supported, so that high rigidity against the rotational force around the z-axis can be obtained.

[0008] JP2016-226090 A discloses a motor with a built-in encoder, comprising an encoder rotating shaft on which a part to be detected is mounted, a receiving case on which a detection unit is mounted, a circuit board that obtains encoder rotating information by processing a signal detected by the detection unit, an encoder bearing that rotatably supports the encoder rotating shaft such that the part to be detected and the detection unit are arranged to face each other across a gap, and a leaf spring-shaped coupling for connecting the receiving case and a stator.

[0009] According to the Fig. In the conventional coupling shown in Figure 3, the two blocks 900 and 100 with higher rigidity must firmly support respective support parts 120, 130, 220, 230, 320, 330, 420, and 430 of the bent portions when a rotational force acts around the z-axis. Therefore, in order to increase the rigidity, the peripheral portions to be screwed to the holes 600 and 800 must be thick. Therefore, there has been a problem that assembly is impracticable in a case where a mounting portion to which an object to be detected, such as a motor, is mounted is narrow and there is interference in the circumference of screw fastening portions.

[0010] In addition, when the support parts 220, 230, 420 and 430 are fastened by screws, the workability is poor because the tightening direction of a tool is from the inside to the outside.

[0011] Furthermore, since it is necessary to arrange the bent portions 210 and 410 on the inside of the thick portions in the circumference of the screw fastening portions, the length of an arm that supports the rotational force around the z-axis is limited and the rigidity cannot be sufficiently increased.

[0012] The position detector coupling requires higher positioning accuracy in the rotational direction around the z-axis during assembly. Therefore, the two rigid blocks 900 and 100, when formed by molding, are insufficient in hole accuracy, and therefore, the formation of screw holes is required. Therefore, removal machining such as milling and tapping is required, which increases the cost of components. SUMMARY

[0013] In view of the problems described above, the present disclosure intends to provide a position detector coupling that can elastically connect attachment portions of an object to be detected and attachment portions of a position detector in both axial and radial directions and that has high torsional rigidity, low cost, and excellent operability.

[0014] The present disclosure discloses a position detector coupling for connecting attachment portions of an object to be detected and attachment portions of a position detector, comprising a shaped, annular thin plate, first and second thick plates, and third and fourth thick plates machined by tapping, wherein the thin plate is provided with a first bent portion and a second bent portion arranged as a pair in positions opposite to each other with respect to a center of the annular shape, and a third bent portion and a fourth bent portion arranged as a pair in positions opposite to each other with respect to the center, wherein the first bent portion and the second bent portion are provided with forked support parts spaced apart in respective tangential circumferential directions,and the third bent portion and the fourth bent portion are provided with forked support parts that are spaced apart in respective tangential circumferential directions, wherein respective forked support parts of the first bent portion and the second bent portion are fixed to the fixing portions of the position detector, wherein the first thick plate and the second thick plate are provided with forked support parts that are spaced apart in respective tangential circumferential directions, the tapping-machined thick plate is screwed to the forked support parts of the third bent portion to insert the forked support parts of the first thick plate, and the tapping-machined fourth thick plate is screwed to the forked support parts of the fourth bent portion to insert the forked support parts of the second thick plate,and the first thick plate and the second thick plate have mounting holes arranged for connection to the ring screwed to the object to be detected.,

[0015] In one embodiment of the present disclosure, the third thick plate and the fourth thick plate are set to be thicker than the thin plate, the first thick plate, and the second thick plate.

[0016] In another embodiment of the present disclosure, the first thick plate and the second thick plate are set to be thicker than the thin plate.

[0017] In yet another embodiment of the present disclosure, the forked support parts of each of the third bent portion and the fourth bent portion are arranged outside the forked support parts of each of the first thick plate and the second thick plate.

[0018] According to the present disclosure, it is possible to reduce the outer dimensions of screw peripheral portions, so that interference can be avoided even in a narrow space. Furthermore, conventional constituent components requiring high-cost machining, particularly the components corresponding to the blocks 900 and 100 of the Fig. 3 can be replaced with the first to fourth thick plates, and cost reduction can be achieved. When the third bent portion is screwed together with the first thick plate and the second thick plate, and the fourth bent portion is screwed together with the first thick plate and the second thick plate, a tightening tool can be used from the outside. Therefore, workability can be improved. Moreover, the third bent portion and the fourth bent portion can be arranged further radially outward under constraints of dimensional limitations. When two axes orthogonal to each other in a plane of the thin plate are defined as the x-axis and the y-axis, and an axis orthogonal to these axes is defined as the z-axis, higher rigidity can be obtained because the length of an arm that supports the rotational force about the z-axis can be extended.Furthermore, since the length of an arm supporting the displacement in the z-axis direction can be extended, improved elastic support can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] (An) embodiment(s) of the present disclosure is (are) described based on the following figures; in which: Fig. 1 is a perspective view illustrating the entire position detector coupling according to an embodiment of the present disclosure; Fig. 2 shows a part of the structure of the position detector coupling according to the embodiment of the present disclosure; and Fig. 3 is a perspective view illustrating an entire conventional position detector coupling. DESCRIPTION OF EMBODIMENTS

[0020] An overall view of a position detector coupling according to the present embodiment is shown in Fig. 1 and a partially detailed view of it is shown in Fig. 2 shown.

[0021] First, an exemplary configuration of the position detector coupling is described with reference to Fig. 1 described in detail.

[0022] The position detector coupling according to the present embodiment is configured to include a shaped thin plate 10, thick plates 50 and 60, and thick plates 70 and 80, each machined at two locations by tapping. The thin plate 10 is an annular member. When two mutually orthogonal axes in a plane thereof are an x-axis and a y-axis, and an axis orthogonal to the x and y axes is a z-axis, the thin plate 10 has bent portions 11, 31, 21, and 41 extending in the z-axis direction. The bent portions 11 and 31 are formed as a pair in positions facing the center of the annular shape interposed therebetween, and function as the first bent portion and the second bent portion, respectively.Likewise, the bent portions 21 and 41 are formed as a pair in positions facing the center of the annular shape interposed therebetween, and function as the third bent portion and the fourth bent portion, respectively. The bent portions 11 and 31 and the bent portions 21 and 41 are angularly spaced in their arrangement positions to form a substantially 90-degree angle therebetween.

[0023] The bent portion 11 has a pair of forked support members 12 and 13 formed at intervals in the tangential circumferential direction, and the bent portion 31 has a pair of forked support members 32 and 33 formed at intervals in the tangential circumferential direction. The forked support members 12 and 13 of the bent portion 11 and the forked support members 32 and 33 of the bent portion 31 are respectively screwed to mounting portions of a position detector.

[0024] The bent portion 21 has a pair of forked support parts 22 and 23 formed at intervals in the tangential circumferential direction, and the bent portion 41 has a pair of forked support parts 42 and 43 formed at intervals in the tangential circumferential direction.

[0025] The thick plate 50 has a curved shape partially bent in the z-axis direction, on which a pair of forked support parts 52 and 53 are formed at intervals. The thick plate 60 has a curved shape partially bent in the z-axis direction, on which a pair of forked support parts 62 and 63 are formed at intervals. The thick plate 50 functions as the first thick plate, and the thick plate 60 functions as the second thick plate.

[0026] Furthermore, the thick plates 70 and 80 are machined by tapping in two places as described above. Thick plate 70 functions as the third thick plate, and thick plate 80 functions as the fourth thick plate.

[0027] The forked support parts 22 and 23 of the bent portion 21 are screwed to the thick plate 70 to insert the forked support parts 52 and 53 of the thick plate 50, using the tapping process of the thick plate 70. Further, the forked support parts 42 and 43 of the bent portion 41 are screwed to the thick plate 80 to insert the forked support parts 62 and 63 of the thick plate 60, using the tapping process of the thick plate 80. That is, the thick plate 70, the thick plate 50, and the bent portion 21 are sequentially arranged in a radial direction from the ring center side to the outside. Likewise, the thick plate 80, the thick plate 60, and the bent portion 41 are sequentially arranged in a radial direction from the ring center side to the outside.

[0028] The curved thick plate 50 has a mounting hole 51 opened in an xy plane thereof. Likewise, the thick plate 60 has a mounting hole 61 opened in an xy plane thereof. The thick plate 50 is screwed, via the mounting hole 51, to a ring 90 on a side on which an object to be detected by the position detector is mounted. Likewise, the thick plate 60 is screwed to the ring 90 via the mounting hole 61. That is, by screwing the thick plates 50 and 60 of the coupling to the ring 90 at mounting portions of the object to be detected and by screwing the curved portions 11 and 31 of the coupling to the mounting portions of the position detector, the mounting portions of the object to be detected and the mounting portions of the position detector are connected to each other.

[0029] In the coupling of the present embodiment, when a rotational force acts around the z-axis, respective forked support parts 12, 13, 32, 33, 22, 23, 42, and 43 of the bent portions 11 and 31 and the bent portions 21 and 41 support the bent portions 11 and 31 and the bent portions 21 and 41 mainly with a compressive or tensile force of the plate. Therefore, high rigidity can be obtained.

[0030] Furthermore, since the forked support members 12, 13, 32, 33, 22, 23, 42, and 43 are arranged at intervals with respect to the bent portions 11 and 31 and the bent portions 21 and 41, when displacement occurs in the x-direction, the bent portions 11 and 31 are displaced relative to the forked support members 12, 13, 32, and 33 in the plate thickness direction, and when displacement occurs in the y-direction, the bent portions 21 and 41 are displaced relative to the forked support members 22, 23, 42, and 43 in the plate thickness direction. Therefore, these members can be elastically supported.

[0031] Furthermore, since the bent portions 11 and 31 and the bent portions 21 and 41 are arranged at intervals, when a displacement occurs in the z-direction, the bent portions 11 and 31 are displaced relative to the bent portions 21 and 41 in the plate thickness direction. Therefore, these members can be elastically supported.

[0032] According to the adopted structure, as in Fig.2, the forked support members 62 and 63 of the thick plate 60 are inserted and bolted along both sides of the bent portion 41 so as to be sandwiched between the forked support members 42 and 43 of the bent portion 41 and the thick plate 80. The thick plate 50, the bent portion 21, and the thick plate 70 located on the opposite side are similarly structured. Therefore, the bent portions 41 and 21 can be arranged further radially outward within the constraints of dimensional limitations. The length of an arm supporting the rotational force about the z-axis can be extended. Consequently, higher rigidity can be obtained. Furthermore, since the length of an arm supporting the displacement in the z-direction can be extended, improved elastic support can be realized.

[0033] Here, the thick plates 70 and 80, which are machined by tapping in two places, are sufficiently thicker than the thin plate 10 and the thick plates 50 and 60, thereby suppressing tilt displacement of the respective forked support parts 22 and 52, 23 and 53, 42 and 62, 43 and 63 of the thin plate 10 and the thick plates 50 and 60 while being twisted in the +y and -y directions around the bent portions 21 and 41, which serve as pivot points when the rotational force around the z-axis acts on the position detector. Each thick plate is machined by tapping in two places. A single thick plate can fix a set of two pivot points with screws to prevent it from tilting and twisting.

[0034] Further, the thick plates 50 and 60 are set to be sufficiently thicker than the thin plate 10 to thereby suppress rotational displacement of respective forked support parts 22 and 52, 23 and 53, 42 and 62, and 43 and 63 of the thin plate 10 and the thick plates 50 and 60 around the y-axis, with the mounting holes 51 and 61 serving as fulcrums when the rotational force around the z-axis acts on the position detector.

[0035] According to the coupling of the present embodiment, it is possible to obtain an excellent connection that is elastic in both axial and radial directions and has high torsional rigidity between the attachment portions of the object to be detected and the attachment portions of the position detector.

Claims

[1] Position detector coupling for connecting mounting portions of an object to be detected and mounting portions of a position detector, comprising: a shaped, ring-shaped thin plate; a first and a second thick plate; and a third and a fourth thick plate machined by tapping, wherein the thin plate is provided with a first bent portion and a second bent portion arranged as a pair in positions opposite to each other with respect to a center of the ring shape, and a third bent portion and a fourth bent portion arranged as a pair in positions opposite to each other with respect to the center the first bent portion and the second bent portion are provided with forked support members spaced apart in respective tangential circumferential directions, and the third bent portion and the fourth bent portion are provided with forked support members spaced apart in respective tangential circumferential directions, respective forked support parts of the first bent portion and the second bent portion are fixed to the fixing portions of the position detector, the first thick plate and the second thick plate are provided with forked support members spaced apart in respective tangential circumferential directions, the third thick plate machined by tapping is screwed to the forked support parts of the third bent section to insert the forked support parts of the first thick plate, and the fourth thick plate machined by tapping is screwed to the forked support parts of the fourth bent section to insert the forked support parts of the second thick plate, and the first thick plate and the second thick plate have mounting holes arranged for connection to the ring screwed to the object to be detected. [2] The position detector coupling according to claim 1, wherein the third thick plate and the fourth thick plate are set to be thicker than the thin plate, the first thick plate and the second thick plate. [3] A position detector coupling according to claim 1 or claim 2, wherein the first thick plate and the second thick plate are set to be thicker than the thin plate. [4] The position detector coupling according to any one of claims 1 to 3, wherein the forked support parts of each of the third bent portion and the fourth bent portion are arranged outside the forked support parts of each of the first thick plate and the second thick plate.

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