Conductive ring

Abstract

This invention provides a conductive ring that can suppress the reduction in tension on the shaft. [Solution] The conductive ring 1 comprises an annular conductive holding member 10, a conductive member 20 extending around an axis x, and a spring member 30 extending around an axis x. The conductive member 20 has a plurality of conductive pieces 21 arranged in the circumferential direction at its inner circumferential end 20a. The spring member 30 has a plurality of spring pieces 31 arranged in the circumferential direction at its inner circumferential end 30a. Each of the spring pieces 31 of the spring member 30 is elastically deformable along the axis x and contacts the plurality of conductive pieces 21 of the conductive member 20. The holding member 10 holds the conductive member 20 and the spring member 30 side by side in the axial direction x.

Description

Technical Field

[0004] , , , , , , ,

[0001] The present invention relates to a conductive ring, and more particularly to a conductive ring that forms a conductive path on a rotating shaft.

Background Art

[0002] For example, in a vehicle equipped with an electric motor such as an electric vehicle (EV: Electric Vehicle), the rotating shaft may be charged by an induced current or the like generated during inverter operation, and electromagnetic wave noise may be generated. Such electromagnetic wave noise may cause communication interference to AM radios and other wireless communication devices. In addition, due to such charging of the rotating shaft, electrolytic corrosion may occur in metal parts such as bearings. Therefore, conventionally, devices have been devised for removing the voltage charged on such a rotating shaft, and a conductive ring that forms a conductive path on the rotating shaft has been proposed. For example, a technique is disclosed in which a conductive ring is attached to a motor housing, and a disk-shaped conductive member made of a conductive material is brought into contact with the rotating shaft of the motor to form a conductive path between the rotating shaft and the housing, and the charged voltage is released from the rotating shaft to the housing (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Since the conductive member of a conductive ring slides against the rotating shaft, there has been a conventional need for a conductive member that is both conductive and resistant to wear. For example, Patent Document 1 proposes using conductive PTFE for the conductive member. Due to the properties of PTFE, the tension force of a conductive PTFE member against the rotating shaft is strong at the beginning of use and decreases significantly over time. As a result, the tension force of a conventional conductive PTFE member against the rotating shaft decreases significantly after the desired period of use, and in many cases, it almost disappears. Consequently, the conductivity of a conventional conductive PTFE member decreases significantly after the desired period of use. Thus, there is a need for a configuration in conventional conductive rings that can prevent a decrease in the tension force against the rotating shaft.

[0005] The present invention has been made in view of the above-mentioned problems, and its objective is to provide a conductive ring that can suppress a decrease in tension force on the shaft. [Means for solving the problem]

[0006] To achieve the above objective, the conductive ring according to the present invention comprises a holding member which is an annular conductive member about an axis, a conductive member which is a conductive member extending about the axis, and a spring member which extends about the axis, wherein the conductive member has a plurality of end pieces arranged in the circumferential direction at its inner end and a plurality of through holes extending along the axis, the spring member has a plurality of end pieces arranged in the circumferential direction at its inner end and a plurality of through holes extending along the axis, and each of the plurality of end pieces of the spring member is about the axis The holding member is designed to elastically deform along the conductive member and to contact the plurality of end pieces of the conductive member, and the holding member holds the conductive member and the spring member side by side in the axial direction, and the plurality of through holes of the conductive member and the plurality of through holes of the spring member each overlap each other when viewed in the axial direction, and when the plurality of through holes of the conductive member and the plurality of through holes of the spring member each overlap each other when viewed in the axial direction, the plurality of end pieces of the spring member each contact the plurality of end pieces of the conductive member.

[0007] In a conductive ring according to one aspect of the present invention, the plurality of through holes in the conductive member are provided at positions corresponding to the positions of the plurality of end pieces, and in the spring member, the plurality of through holes are provided at positions corresponding to the positions of the plurality of end pieces.

[0008] In a conductive ring according to one aspect of the present invention, the number of through holes in the conductive member corresponds to the number of end pieces, and the number of through holes in the spring member corresponds to the number of end pieces.

[0009] In a conductive ring according to one aspect of the present invention, the plurality of through holes in the conductive member are provided at intervals from each other around the axis, and the plurality of through holes in the spring member are provided at intervals from each other around the axis.

[0010] In a conductive ring according to one aspect of the present invention, the retaining member has a plurality of through holes extending along the axis, and the plurality of through holes of the retaining member are arranged to overlap with the plurality of through holes of the conductive member and the plurality of through holes of the spring member when viewed in the axial direction.

[0011] In a conductive ring according to one aspect of the present invention, the plurality of end pieces of the spring member are arranged with a gap between them in the circumferential direction.

[0012] In a conductive ring according to one aspect of the present invention, the circumferential width of the end piece of the spring member is less than or equal to the circumferential width of the end piece of the conductive member.

[0013] In a conductive ring according to one aspect of the present invention, the outer peripheral ends of the plurality of end pieces of the spring member are located further outward than the outer peripheral ends of the plurality of end pieces of the conductive member, and when the plurality of through holes of the conductive member and the plurality of through holes of the spring member overlap each other in the axial direction, the outer peripheral ends of the plurality of end pieces of the spring member are located further outward than the outer peripheral ends of the plurality of end pieces of the conductive member.

[0014] In a conductive ring according to one aspect of the present invention, the spring member has a base which is an annular portion, the plurality of end pieces of the spring member extend inward from the inner circumference end of the base of the spring member, and the plurality of through holes of the spring member are provided in the base.

[0015] In a conductive ring according to one aspect of the present invention, the plurality of end pieces of the conductive member are arranged with a gap between them in the circumferential direction.

[0016] In a conductive ring according to one aspect of the present invention, the conductive member has a base which is an annular portion, the plurality of end pieces of the conductive member extend inward from the inner circumference end of the base of the conductive member, and the plurality of through holes of the conductive member are provided in the base.

[0017] In the conductive ring according to one aspect of the present invention, the number of the plurality of end pieces of the spring member is the same as the number of the plurality of end pieces of the conductive member.

[0018] In the conductive ring according to one aspect of the present invention, the holding member is configured to hold the conductive member and the spring member on the outer peripheral side.

[0019] In the conductive ring according to one aspect of the present invention, the conductive member is formed of conductive PTFE having conductivity.

Advantages of the Invention

[0020] According to the conductive ring of the present invention, it is possible to suppress a decrease in the pressing force against the shaft.

Brief Description of the Drawings

[0021] [Figure 1] It is a perspective view showing a schematic configuration of a conductive ring according to an embodiment of the present invention. [Figure 2] It is a perspective view showing a schematic configuration of a conductive ring according to an embodiment of the present invention. [Figure 3] It is an exploded perspective view of the conductive ring. [Figure 4] It is a front view of the conductive ring. [Figure 5] It is a rear view of the conductive ring. [Figure 6] It is a cross-sectional view showing a cross-section along line A-A in FIG. 5. [Figure 7] It is a cross-sectional view showing one side with respect to the axis of the conductive ring shown in FIG. 6. [Figure 8] It is a partially enlarged front view showing a part of the conductive member enlarged. [Figure 9] It is a view showing a cross-section of the conductive ring in a cross-section along line B-B in FIG. 5. [Figure 10] It is a partially enlarged front view showing a part of the spring member enlarged. [Figure 11] It is a conceptual diagram for showing an example of an application target of the conductive ring. [Figure 12] Figure 11 is a cross-sectional view showing an example of the usage state of a conductive ring in the application shown. [Figure 13] This is a front view of an example of a modified conductive material. [Figure 14] This is a front view of another example of a modified conductive member. [Figure 15] This is a front view of an example of a modified spring member. [Figure 16] This is a front view of another example of a modified spring member. [Modes for carrying out the invention]

[0022] Embodiments of the present invention will be described below with reference to the drawings. In the drawings, not all of the components are assigned reference numerals, and some of the reference numerals for components may be omitted.

[0023] The conductive ring according to an embodiment of the present invention forms a conductive passage on a rotating shaft, for example, between the shaft and the hole through which the shaft is inserted. The applications to which the conductive ring according to an embodiment of the present invention can be applied are not limited to this. Figures 1 and 2 are perspective views showing a schematic configuration of the conductive ring 1 according to an embodiment of the present invention, and Figure 3 is an exploded perspective view of the conductive ring 1. Figure 4 is a front view of the conductive ring 1, and Figure 5 is a rear view of the conductive ring 1. Figure 6 is a cross-sectional view showing a plane containing the axis x of the conductive ring 1, and is a cross-sectional view showing the cross-section along line AA in Figure 5. Figure 7 is a cross-sectional view showing one side of the conductive ring 1 with respect to the axis x shown in Figure 6. Figure 1 is a perspective view of the conductive ring 1 seen from the front, and Figure 2 is a perspective view of the conductive ring 1 seen from the rear.

[0024] As shown in Figures 1-7, the conductive ring 1 comprises a holding member 10 which is an annular conductive member around axis x, a conductive member 20 which is a conductive member extending around axis x, and a spring member 30 which extends around axis x. The conductive member 20 has a plurality of conductive pieces 21 which are end pieces arranged in the circumferential direction at its inner circumference end 20a, and also has a plurality of through holes 29 which extend along axis x. The spring member 30 has a plurality of spring pieces 31 which are end pieces arranged in the circumferential direction at its inner circumference end 30a, and also has a plurality of through holes 36 which extend along axis x. Each of the plurality of spring pieces 31 of the spring member 30 is elastically deformable along axis x and is in contact with the plurality of conductive pieces 21 of the conductive member 20. The holding member 10 holds the conductive member 20 and the spring member 30 side by side in the axial direction x. The multiple through holes 29 of the conductive member 20 and the multiple through holes 36 of the spring member 30 are arranged to overlap each other when viewed in the direction of the axis x. When the multiple through holes 29 of the conductive member 20 and the multiple through holes 36 of the spring member 30 overlap each other when viewed in the direction of the axis x, the multiple spring pieces 31 of the spring member 30 each come into contact with the multiple conductive pieces 21 of the conductive member 20. The configuration of the conductive ring 1 will be described in detail below. The inner circumference is the side that approaches the axis x in the direction perpendicular to the axis x (hereinafter also referred to as the radial direction), and the outer circumference is the side that moves away from the axis x in the radial direction.

[0025] The conductive member 20 is, for example, an annular plate-shaped member about an axis x, as shown in Figures 1 to 7, and has a pair of annular surfaces facing away from each other in the direction of the axis x, namely a contact surface 24 and a pressed surface 25. As shown in Figures 6 and 7, the contact surface 24 faces one side (front side) in the direction of the axis x, and the pressed surface 25 faces the other side (back side) in the direction of the axis x. As described above, the conductive member 20 has a plurality of conductive pieces 21 at the inner circumference end 20a, which is the inner circumference end, and also has an annular base portion 22. As shown in Figures 6 and 7, the base portion 22 is the part of the conductive member 20 that is on the outer circumference side of the conductive pieces 21. From the inner circumference end 22a, which is the inner circumference end of the base portion 22, the plurality of conductive pieces 21 extend toward the inner circumference. The base portion 22 is an annular plate-shaped portion around an axis x, as shown in Figures 3, 6, and 7, for example, and the inner circumferential end 22a extends along a cylindrical surface with axis x as its central axis, for example. Specifically, for example, the inner circumferential end 22a extends on a cylindrical surface or a substantially cylindrical surface with axis x as its central axis. The outer circumferential end 22b also extends along a cylindrical surface with axis x as its central axis, for example, and specifically, for example, the outer circumferential end 22b extends on a cylindrical surface or a substantially cylindrical surface with axis x as its central axis. The outer circumferential end 22b is the outer-circumferential end of the base portion 22, and specifically, it is the end face facing the outer circumference of the base portion 22.

[0026] Figure 8 is a partially enlarged front view showing an enlarged portion of the conductive member 20. As shown in Figures 4, 5, and 8, the multiple conductive pieces 21 are arranged at intervals from each other in the circumferential direction. As shown in Figure 8, the conductive pieces 21 have, for example, a rectangular or substantially rectangular plate shape and have an inner circumferential end 21a, which is the inner circumferential end, a pair of circumferential ends 21b and 21c, and an outer circumferential end 21d, which is the outer circumferential end. Specifically, the inner circumferential end 21a is an end face facing the inner circumferential side, and the circumferential ends 21b and 21c are specifically end faces facing the circumferential direction. The side faces 21b and 21c are facing away from each other in the circumferential direction. The outer circumferential end 21d is specifically the boundary between the conductive piece 21 and the base 22, and the conductive piece 21 is connected to the inner circumferential end 22a of the base 22 at the outer circumferential end 21d. The outer peripheral end 21d of the conductive piece 21 and the inner peripheral end 22a of the base portion 22 are located at a predetermined distance R1 in the radial direction from the axis x.

[0027] The inner circumferential end 21a of the conductive piece 21 extends, for example, along a plane perpendicular to the radial direction. Specifically, the inner circumferential end 21a of the conductive piece 21 extends, for example, along a plane perpendicular to the radial direction or a substantially plane. The inner circumferential end 21a is located at a predetermined distance R2 in the radial direction from the axis x. The sides 21b and 21c of the conductive piece 21 each extend, for example, along the radial direction. Specifically, the side ends 21b and 21c of the conductive piece 21 each extend, for example, along a plane containing the axis x or a substantially plane. The width W1 of the conductive piece 21, which is the circumferential width, is a predetermined size. Note that the width W1 of the conductive piece 21 is the distance between the side 21b and the side 21c. Also, the length L1 of the conductive piece 21 is a predetermined length. Note that the length L1 of the conductive piece 21 is the length in the radial direction, and is the radial distance between the inner circumferential end 21a and the outer circumferential end 21d.

[0028] As described above, the multiple conductive pieces 21 are arranged in the circumferential direction, and as shown in Figures 4, 5, and 8, a gap 23 is formed between two conductive pieces 21 that are adjacent to each other in the circumferential direction. The gap 23 extends to the inner circumferential end 22a of the base 22. In other words, between two conductive pieces 21 that are adjacent to each other in the circumferential direction, the side end 21b of one conductive piece 21 and the side end 21c of the other conductive piece 21 face each other through the gap 23. The width W2 of the gap 23 is a predetermined size. Note that the width W2 of the gap 23 is the distance between the side end 21b of one conductive piece 21 and the side end 21c of the other conductive piece 21 between two adjacent conductive pieces 21. The width W2 of the gap 23 is, for example, narrow.

[0029] As an example, as shown in Figure 8, the side ends 21b and 21c of the conductive piece 21 each extend along a plane containing the axis x, and the width W1 of the conductive piece 21 widens radially from the inner end 21a to the outer end 21d. In this case, the width W2 of the gap 23 is constant radially. Note that this configuration of the conductive piece 21 is just an example, and the width W1 of the conductive piece 21 does not have to widen radially from the inner end 21a to the outer end 21d, nor does the width W2 of the gap 23 have to be constant radially. For example, the conductive piece 21 may have a configuration in which the width W1 of the conductive piece 21 is constant radially, and correspondingly, the width W2 of the gap 23 may narrow radially from the inner side to the outer side. Furthermore, for example, the conductive piece 21 may have a shape that narrows in the radial direction from the inner circumferential end 21a to the outer circumferential end 21d, and correspondingly, the width W2 of the gap 23 may widen in the radial direction from the inner side to the outer side.

[0030] The widths W1 of the multiple conductive pieces 21 are all the same or approximately the same, and the widths W2 of the multiple gaps 23 are all the same or approximately the same. Therefore, in the conductive member 20, the multiple conductive pieces 21 are arranged at equal or approximately equal angular intervals around the axis x, and the multiple gaps 23 are arranged at equal or approximately equal angular intervals around the axis x. Note that the widths W1 of the multiple conductive pieces 21 do not have to be the same, and the widths W2 of the multiple gaps 23 do not have to be the same. Also, in the conductive member 20, the multiple conductive pieces 21 do not have to be arranged at equal angular intervals around the axis x, and the multiple gaps 23 do not have to be arranged at equal angular intervals around the axis x.

[0031] Furthermore, as shown in Figures 4 and 5, the inner circumferential ends 21a of the multiple conductive pieces 21 are aligned along a circle centered on axis x, for example, when viewed in the direction of axis x. Specifically, for example, the inner circumferential ends 21a of the multiple conductive pieces 21 are located on a circle or approximately a circle centered on axis x when viewed in the direction of axis x, and the distance R2 from axis x to each of the inner circumferential ends 21a of the multiple conductive pieces 21 is the same or approximately the same. In other words, the inner circumferential ends 21a of the multiple conductive pieces 21 are located on a circle with radius R2 or approximately a circle with radius R2 centered on axis x when viewed in the direction of axis x. The inner circumferential ends 21a of the multiple conductive pieces 21 form the inner circumferential ends of the conductive member 20, defining a circular or approximately circular space (through hole) 20b that penetrates the conductive member 20 in the direction of axis x.

[0032] A shaft for forming a conductive passage is inserted into the through-hole 20b. In the usage state described later, the shaft is passed through the through-hole 20b, and each of the conductive pieces 21 contacts the outer surface of the shaft. In this way, each conductive piece 21 has an overlap δ between itself and the shaft in the usage state. Specifically, the distance R2 from the axis x to the inner circumferential end 21a of each conductive piece 21 is larger than the radius R0 of the shaft by the overlap δ.

[0033] As shown in Figures 6 and 7, the contact surface 24 of the conductive member 20 extends, for example, along a plane perpendicular to the axis x. Specifically, the contact surface 24 extends, for example, along a plane perpendicular to the axis x or a substantially plane. Also, as shown in Figures 6 and 7, the pressed surface 25 of the conductive member 20 extends, for example, along a plane perpendicular to the axis x. Specifically, the pressed surface 25 extends, for example, along a plane perpendicular to the axis x or a substantially plane. Each of the multiple conductive pieces 21 and base 22 has a part of the contact surface 24 and the pressed surface 25, and the multiple conductive pieces 21 and base 22 are connected flush. The thickness T1 of the conductive member 20 is a predetermined size. The thickness T1 of the conductive member 20 is, for example, constant or substantially constant throughout the entire conductive member 20. Note that the thickness T1 of the conductive member 20 is the distance between the contact surface 24 and the pressed surface 25.

[0034] As described above, the conductive member 20 has a plurality of conductive pieces 21 arranged in the circumferential direction at its inner circumferential end 20a, with a gap 23 formed between two adjacent conductive pieces 21. In this way, the inner circumferential end 20a of the conductive member 20 is divided into multiple parts along the circumferential direction. This reduces the tensioning force that the conductive member 20 exerts on the shaft, even when the conductive member 20 deforms as the shaft passes through it during use, as described later. The tensioning force is the force that tightens the shaft 110. The magnitude of the tensioning force that the conductive member 20 exerts on the shaft corresponds to the number of conductive pieces 21. Therefore, the number of conductive pieces 21 corresponds, for example, to the magnitude of the tensioning force that the conductive member 20 exerts on the shaft.

[0035] Furthermore, the magnitude of the tension force that the conductive member 20 itself exerts on the shaft can be adjusted by adjusting the width W1, length L1, and thickness T2 of each conductive piece 21. For this reason, the width W1, length L1, and thickness T2 of each conductive piece 21 are set to values ​​such that, for example, the magnitude of the tension force that the conductive member 20 itself exerts on the shaft becomes a predetermined magnitude when the conductive ring 1 is in use.

[0036] As described above, the conductive member 20 has a plurality of through holes 29, and the through holes 29 penetrate the conductive member 20 in the axial x direction. Furthermore, the plurality of through holes 29 of the conductive member 20 are arranged to overlap each other in the axial x direction with respect to the plurality of through holes 36 of the spring member 30. The plurality of through holes 29 are provided so that the conductive member 20 and the spring member 30 can overlap each other at predetermined relative positions. Specifically, the plurality of through holes 29 are provided so that the plurality of conductive pieces 21 can each contact the plurality of spring pieces 31 at predetermined relative positions.

[0037] Specifically, as shown in Figures 3, 8, and 9, multiple through holes 29 are provided in the base 22, and each through hole 29 extends between the contact surface 24 and the pressed surface 25 along an axis x1 parallel to axis x, penetrating the base 22. Figure 9 is a diagram showing a cross-section of the conductive ring 1 along line BB in Figure 5. For example, as shown in Figures 8 and 9, the through holes 29 are through holes with axis x1 as the central axis. As an example, the through holes 29 are cylindrical or substantially cylindrical through holes with axis x1 as the central axis, and the cross-section of the through hole 29 perpendicular to axis x1 is circular or substantially circular. However, the through holes 29 are not limited to cylindrical through holes. For example, the shape of the cross-section of the through hole 29 perpendicular to axis x1 may be a polygon such as a triangle or rectangle, or other shapes.

[0038] Furthermore, as shown in Figures 3, 8, and 9, in the conductive member 20, the multiple through holes 29 are provided, for example, spaced apart from each other around the axis x. Specifically, for example, the multiple through holes 29 are provided at equal or approximately equal angular intervals around the axis x. Also, for example, as shown in Figures 8 and 9, the multiple through holes 29 are provided at the same or approximately the same radial distance from the axis x. Specifically, as shown in Figure 9, the axis x1 of each through hole 29 is provided at a radial distance R7 from the axis x, and in a plane perpendicular to the axis x, the axis x1 of each through hole 29 is located on a circle with radius R7 centered on the axis x. Thus, as an example, the multiple through holes 29 in the conductive member 20 are rotationally symmetric or approximately rotationally symmetric with respect to the axis x.

[0039] Furthermore, in the conductive member 20, the multiple through holes 29 are provided at positions corresponding to the positions of the multiple conductive pieces 21, for example. Specifically, as will be described later, when the multiple through holes 29 of the conductive member 20 and the multiple through holes 36 of the spring member 30 are superimposed, the multiple conductive pieces 21 are provided at positions corresponding to the positions of the multiple conductive pieces 21 so that each of the multiple conductive pieces 21 contacts the multiple spring pieces 31 at a predetermined relative position. As an example, as shown in Figure 8, the axis x1 of each through hole 29 is located on the radial line y1 that passes through the gap 23 between adjacent conductive pieces 21.

[0040] Furthermore, in the conductive member 20, the number of through holes 29 corresponds to the number of conductive pieces 21. Specifically, as will be described later, when the multiple through holes 29 of the conductive member 20 and the multiple through holes 36 of the spring member 30 are superimposed, the number of conductive pieces 21 is set to correspond to the number of conductive pieces 21 so that each of the multiple conductive pieces 21 contacts each of the multiple spring pieces 31 at a predetermined relative position. For example, the number of through holes 29 is set to a common divisor of the number of conductive pieces 21.

[0041] Furthermore, the multiple through holes 29 are not limited to those having the specific form described above. The multiple through holes 29 are sufficient as long as each of the multiple through holes 29 is superimposed on the multiple through holes 36 of the spring member 30 when viewed in the axial x direction. Also, when each of the multiple through holes 29 is superimposed on the multiple through holes 36 of the spring member 30 when viewed in the axial x direction, the multiple conductive pieces 21 are sufficient as long as each of the multiple spring pieces 31 is in contact with the multiple spring pieces 31 at a predetermined relative position.

[0042] The conductive member 20 has the above-described structure and is integrally formed from a conductive material. That is, the plurality of conductive pieces 21 and the base 22 are part of the integrally formed conductive member 20, and the plurality of conductive pieces 21 and the base 22 are integral. The conductive material forming the conductive member 20 is, for example, a base material to which a conductive material has been added, specifically, conductive PTFE (polytetrafluoroethylene). Conductive PTFE is obtained by adding a conductive material to PTFE (polytetrafluoroethylene) as the base material. Note that the base material of the conductive member 20 is not limited to PTFE. The base material of the conductive member 20 may be, for example, other resins, rubber, or fibers such as nonwoven fabrics, and the material of the conductive member 20 may be one of these base materials to which a conductive material has been added. Examples of conductive materials to be added to the base material include conductive particles such as carbon or metal powder.

[0043] The spring member 30 is provided in the conductive ring 1 alongside the conductive member 20 in the axial x direction. The spring pieces 31 of the spring member 30 are elastically deformed along the axial x, generating an elastic force in the direction toward the axial x. Note that the direction toward the axial x is not limited to the direction toward the inner circumference in the radial direction, but can be any direction having a component toward the inner circumference in the radial direction. The spring member 30 is, for example, annular around the axial x. Specifically, the spring member 30 is an annular leaf spring, and in the operating state of the conductive ring 1 described later, when the multiple spring pieces 31 are elastically deformed, the multiple conductive pieces 21 of the conductive member 20 are pressed against the outer circumferential surface 110a of the shaft 110 (see Figure 12), generating an elastic force such that the multiple conductive pieces 21 exert a predetermined tension force on the shaft 110. In this way, multiple spring pieces 31 cooperate with multiple conductive pieces 21 so that the multiple conductive pieces 21 generate a predetermined tension force on the shaft 110.

[0044] The spring member 30 is, for example, an annular plate-shaped member about an axis x, as shown in Figures 1 to 7, and has a pair of annular surfaces, a pressing side 34 and a back surface 35, which are opposite to each other in the direction of the axis x, as shown in Figures 3, 6, and 7. The pressing side 34 faces the front side, and the back surface 35 faces the back side. As described above, the spring member 30 has a plurality of spring pieces 31 at the inner circumference end 30a, which is the inner circumference end, and also has an annular base portion 32. The base portion 32 is the part of the spring member 30 that is on the outer circumference side of the spring pieces 31, as shown in Figures 3, 6, and 7. The plurality of spring pieces 31 extend inward from the inner circumference end 32a, which is the inner circumference end of the base portion 32. The base portion 32 is an annular plate-shaped portion around an axis x, as shown in Figures 3, 6, and 7, for example, and the inner circumferential end 32a extends along a cylindrical surface with axis x as its central axis, for example. Specifically, for example, the inner circumferential end 32a extends on a cylindrical surface or a substantially cylindrical surface with axis x as its central axis. Similarly, the outer circumferential end 32b extends along a cylindrical surface with axis x as its central axis, for example, and specifically, for example, the outer circumferential end 32b extends on a cylindrical surface or a substantially cylindrical surface with axis x as its central axis. The outer circumferential end 32b is the outer-circumferential end of the base portion 32, and specifically, it is the end face facing the outer circumference of the base portion 32.

[0045] Figure 10 is a partially enlarged front view showing an enlarged portion of the spring member 30. As shown in Figures 2, 5, and 10, the multiple spring pieces 31 are arranged at intervals from each other in the circumferential direction. As shown in Figure 10, the spring piece 31 has, for example, a rectangular or substantially rectangular plate shape and has an inner circumferential end 31a, which is the inner circumferential end, a pair of circumferential ends 31b and 31c, and an outer circumferential end 31d, which is the outer circumferential end. Specifically, the inner circumferential end 31a is an end face facing the inner circumferential side, and specifically, the circumferential ends 31b and 31c are end faces facing the circumferential direction. The circumferential ends 31b and 31c face away from each other in the circumferential direction. The outer circumferential end 31d is specifically the boundary between the spring piece 31 and the base 32, and the spring piece 31 is connected to the inner circumferential end 32a of the base 32 at the outer circumferential end 31d. The outer peripheral end 31d of the spring piece 31 and the inner peripheral end 32a of the base portion 32 are located at a predetermined distance R3 in the radial direction from the axis x.

[0046] The inner circumferential end 31a of the spring piece 31 extends, for example, along a plane perpendicular to the radial direction, and the inner circumferential end 31a is located at a predetermined distance R4 radially from the axis x. The side ends 31b and 31c of the spring piece 31 extend, for example, along the radial direction. Specifically, the side ends 31b and 31c of the spring piece 31 extend, for example, along a plane containing the axis x or a substantially plane. The width W3, which is the circumferential width of the spring piece 31, is of a predetermined size. Note that the width W3 of the spring piece 31 is the distance between the side 31b and the side 31c. The width W3 of the spring piece 31 is less than or equal to the width W1 of the conductive piece 21 (W3 ≤ W1). As an example, as shown in Figure 5, the width W3 of the spring piece 31 is smaller than the width W1 of the conductive piece 21. Specifically, for example, the width W3 of the spring piece 31 is smaller than the overall width W1 of the conductive piece 21. Furthermore, as shown in Figure 10, the length L2 of the spring piece 31 is a predetermined length. The length L2 of the spring piece 31 is the radial distance between the inner circumference end 31a and the outer circumference end 31d. The thickness T2 of the spring piece 31 (see Figure 3) is also a predetermined size. The thickness T2 of the spring piece is, for example, constant or approximately constant throughout the entire spring piece 31. The thickness T2 of the spring piece 31 is the distance between the pressing surface 34 and the back surface 35 of the spring piece 31.

[0047] As described above, the spring piece 31 is designed to elastically deform along the axis x, and specifically, as will be described later, it is designed to press the deformed conductive piece 21 toward the axis x when the conductive ring 1 is in use. The width W3, length L2, and thickness T2 of the spring piece 31 are set to values ​​such that, for example, when the conductive ring 1 is in use, it presses the deformed conductive piece 21 toward the axis x with a predetermined force.

[0048] As described above, the multiple spring pieces 31 are arranged in the circumferential direction, and as shown in Figures 5 and 9, a space 33 is formed between two adjacent spring pieces 31 in the circumferential direction. The space 33 is defined between two adjacent spring pieces 31 in the circumferential direction by the side end 31b of one spring piece 31, the side end 31c of the other spring piece 31, and the inner circumferential end 32a of the base portion 32 extending between these two spring pieces 31. As shown in Figure 10, the width W4 of the space 33 in the circumferential direction is a predetermined size. The width W4 of the space 33 is the distance between the side end 31b of one spring piece 31 and the side end 31c of the other spring piece 31 between two adjacent spring pieces 31. The width W4 of the space 33 is wider than the width W2 of the gap 23 of the conductive member 20.

[0049] The widths W3 of the multiple spring pieces 31 are all the same or approximately the same, and the widths W4 of the multiple spaces 33 are all the same or approximately the same. Therefore, in the spring member 30, the multiple spring pieces 31 are arranged at equal or approximately equal angular intervals around the axis x, and the multiple spaces 33 are arranged at equal or approximately equal angular intervals around the axis x. Note that the widths W3 of the multiple spring pieces 31 do not have to be the same, and the widths W4 of the multiple spaces 33 do not have to be the same. Also, in the spring member 30, the multiple spring pieces 31 do not have to be arranged at equal angular intervals around the axis x, and the multiple spaces 33 do not have to be arranged at equal angular intervals around the axis x.

[0050] Furthermore, as shown in Figure 7, in the conductive ring 1, the outer peripheral ends 31d of the multiple spring pieces 31 are located further outward than the outer peripheral ends 21d of the multiple conductive pieces 21. In other words, the radius R3 of the inner peripheral end 32a of the base 32 of the spring member 30 is larger than the radius R1 of the inner peripheral end 22a of the base 22 of the conductive member 20.

[0051] As shown in Figure 5, the inner ends 31a of the multiple spring pieces 31 are aligned along a circle centered on axis x, for example, when viewed in the direction of axis x. Specifically, for example, the inner ends 31a of the multiple spring pieces 31 are located on a circle or approximately a circle centered on axis x, and the distance R4 from axis x to each of the inner ends 31a of the multiple spring pieces 31 is the same or approximately the same. In other words, the inner ends 31a of the multiple spring pieces 31 are located on a circle with radius R4 or approximately a circle with radius R4 centered on axis x, when viewed in the direction of axis x.

[0052] As shown in Figures 6 and 7, the pressing surface 34 of the spring member 30 is, for example, aligned with a plane perpendicular to the axis x. Specifically, the pressing surface 34 extends on a plane perpendicular to the axis x or a substantially flat plane. Also, as shown in Figures 6 and 7, the back surface 35 of the spring member 30 is, for example, aligned with a plane perpendicular to the axis x. Specifically, the back surface 35 extends on a plane perpendicular to the axis x or a substantially flat plane. Each of the multiple spring pieces 31 and the base 32 has a portion of the pressing surface 34 and the back surface 35, and the multiple spring pieces 31 and the base 32 are connected flush with each other.

[0053] As shown in Figures 6 and 7, the spring member 30 is shaped to overlap the conductive member 20 in the axial x direction. For example, the base 32 of the spring member 30 has the same or approximately the same shape and size as the portion of the base 22 of the conductive member 20 from the outer peripheral end 22b to the vicinity of the inner peripheral end 22a, so that the outer peripheral end 32b of the base 32 of the spring member 30 and the outer peripheral end 22b of the base 22 of the conductive member 20 coincide or approximately coincide with each other, causing the spring member 30 and the conductive member 20 to overlap.

[0054] Furthermore, as shown in Figures 5-7, in the conductive ring 1, each of the multiple spring pieces 31 is in contact with each of the multiple conductive pieces 21. Specifically, the number of multiple spring pieces 31 is equal to the number of multiple conductive pieces 21, and one of the multiple spring pieces 31 corresponds to one of the multiple conductive pieces 21. Each spring piece 31 is in contact with the corresponding conductive piece 21, and specifically, the pressing surface 34 of each spring piece 31 is in contact with the pressed surface 25 of the corresponding conductive piece 21. The distance R4 from the axis x of the inner circumferential end 31a of the spring piece 31, the length L2 of the spring piece 31, and the width W4 of the space 33, which is the width between two adjacent spring pieces 31 in the circumferential direction, are set so that each spring piece 31 is in contact with the corresponding conductive piece 21.

[0055] As described above, in the conductive ring 1, the outer peripheral end 31d of the spring piece 31 is located further outward than the outer peripheral end 21d of the conductive piece 21, and the spring piece 31 extends from the vicinity of the inner peripheral end 22a of the base 22 of the conductive member 20, beyond the inner peripheral end 22a, to the conductive piece 21. For example, the spring piece 31 extends to a position on the outer peripheral end 22d side of the radial center of the conductive piece 21, and the inner peripheral end 31a of the spring piece 31 is located on the outer peripheral end 22d side of the radial center of the conductive piece 21. However, the spring piece 31 is not limited to extending to a position on the outer peripheral end 22d side of the radial center of the conductive piece 21. For example, the spring piece 31 may extend to the radial center or near the center of the conductive piece 21, or it may extend to a position on the inner peripheral end 21a side of the radial center of the conductive piece 21. Thus, the radius R4 of the inner circumference end 31a of the spring piece 31 is larger than the radius R2 of the inner circumference end 21a of the conductive piece 21, and smaller than the radius R1 of the outer circumference end 21d of the conductive piece 21. However, the radius R4 of the inner circumference end 31a of the spring piece 31 may be the same as, or smaller than, the radius R2 of the inner circumference end 21a of the conductive piece 21. For example, in the usage state of the conductive ring 1 described later, the radius R4 of the inner circumference end 31a of the spring piece 31 may be smaller than the radius R2 of the inner circumference end 21a of the conductive piece 21, as long as the spring piece 31 does not come into contact with the shaft.

[0056] Also, as shown in FIG. 5, for example, the spring piece 31 is configured to contact the center or substantially the center in the circumferential direction of the conductive piece 21. Further, the spring piece 31 is configured to contact the conductive piece 21 inside the side ends 21b and 21c in the circumferential direction. That is, the width W2 of the spring piece 31 is smaller than the width W1 of the conductive piece 21 (W2 < W1). Note that the position in the circumferential direction where the spring piece 31 contacts the conductive piece 21 is not limited to the above-described position. Also, the width W2 of the spring piece 31 is not limited to being smaller than the width W1 of the conductive piece 21.

[0057] As described above, the spring member 30 has a plurality of through holes 36, and the through holes 36 penetrate the spring member 30 in the axial direction of the axis x. The plurality of through holes 36 of the spring member 30 are respectively arranged to overlap with the plurality of through holes 29 of the conductive member 20 when viewed in the axial direction of the axis x. The plurality of through holes 36 are provided to enable the spring member 30 and the conductive member 20 to be overlapped with each other at a predetermined relative position. Specifically, the plurality of through holes 36 are provided to enable the plurality of spring pieces 31 to contact the plurality of conductive pieces 21 at a predetermined relative position.

[0058] Specifically, as shown in Figures 3, 9, and 10, multiple through holes 36 are provided in the base portion 32, and each through hole 36 extends between the pressing side portion 34 and the back portion 35 along an axis x2 parallel to axis x, penetrating the base portion 32. For example, as shown in Figures 9 and 10, the through hole 36 is a through hole with axis x2 as its central axis. Also, for example, the shape of the cross section of the through hole 36 perpendicular to axis x2 is the same as or approximately the same as the shape of the cross section of the through hole 29 of the conductive member 20 perpendicular to axis x1. As an example, the through hole 36 is a cylindrical or approximately cylindrical through hole with axis x2 as its central axis, and the cross section of the through hole 36 perpendicular to axis x2 is circular or approximately circular, of the same size as or approximately the same size as the cross section of the through hole 29 perpendicular to axis x1. Note that the through hole 36 is not limited to a cylindrical through hole. For example, the shape of the cross section perpendicular to the axis x2 of the through hole 36 may be a polygon such as a triangle or rectangle, corresponding to the shape of the through hole 29 of the conductive member 20, or it may be any other shape. Also, the shape of the cross section perpendicular to the axis x2 of the through hole 36 does not have to be the same as the shape of the cross section perpendicular to the axis x1 of the through hole 29 of the conductive member 20.

[0059] Furthermore, as shown in Figures 3, 9, and 10, in the spring member 30, the multiple through holes 36 are provided, for example, spaced apart from each other around the axis x. Specifically, for example, the multiple through holes 36 are provided at equal or approximately equal angular intervals around the axis x. Also, for example, as shown in Figures 9 and 10, the multiple through holes 36 are provided at the same or approximately the same radial distance from the axis x. Specifically, as shown in Figure 10, the axis x2 of each through hole 36 is provided at a radial distance R8 from the axis x, and in a plane perpendicular to the axis x, the axis x2 of each through hole 36 is located on a circle with radius R8 centered on the axis x. Thus, in the spring member 30, the multiple through holes 36 are, as an example, rotationally symmetric or approximately rotationally symmetric with respect to the axis x.

[0060] Furthermore, in the spring member 30, the multiple through holes 36 are provided at positions corresponding to the positions of the multiple spring pieces 31, for example. Specifically, as will be described later, when the multiple through holes 36 of the spring member 30 and the multiple through holes 29 of the conductive member 20 are superimposed, the multiple through holes 36 are provided at positions corresponding to the positions of the multiple spring pieces 31 so that each of the multiple spring pieces 31 contacts the multiple conductive pieces 21 at a predetermined relative position. As an example, as shown in Figure 10, the axis x2 of each through hole 36 is located on the radial line y2 that passes through the space 33 between adjacent spring pieces 31.

[0061] Furthermore, in the spring member 30, the number of through holes 36 corresponds to the number of spring pieces 31. Specifically, as will be described later, when the multiple through holes 36 of the spring member 30 and the multiple through holes 29 of the conductive member 20 are superimposed, the number of through holes 36 is set to correspond to the number of spring pieces 31 so that each of the multiple spring pieces 31 contacts the multiple conductive pieces 21 at a predetermined relative position. For example, the number of through holes 36 is set to a common divisor of the number of spring pieces 31.

[0062] As described above, each of the multiple through holes 36 in the spring member 30 is arranged to overlap with each other in the direction of the axis x of the multiple through holes 29 in the conductive member 20. For example, each of the multiple through holes 36 is arranged to coincide with or approximately coincide with each other in the direction of the axis x of the multiple through holes 29. In this case, as described above, the cross-sectional shape of the through hole 36 perpendicular to the axis x2 is the same as or approximately the same as the cross-sectional shape of the through hole 29 of the conductive member 20 perpendicular to the axis x1, the distance R8 of the axis x2 of the through hole 36 from the axis x is the same as or approximately the same as the distance R7 of the axis x1 of the through hole 29 from the axis x, the circumferential spacing between two adjacent through holes 36 is the same as or approximately the same as the circumferential spacing between two adjacent through holes 29, and the number of through holes 36 is the same as the number of through holes 29.

[0063] As described above, in the spring member 30, the multiple through holes 36 are provided at positions corresponding to the positions of the multiple spring pieces 31, and similarly, in the conductive member 20, the multiple through holes 29 are provided at positions corresponding to the positions of the multiple conductive pieces 21. This allows the multiple spring pieces 31 to contact the multiple conductive pieces 21 at predetermined relative positions when each of the multiple through holes 36 is superimposed on the multiple through holes 29.

[0064] Furthermore, as described above, the multiple through holes 36 in the spring member 30 are rotationally symmetric with respect to axis x, and the multiple through holes 29 in the conductive member 20 are rotationally symmetric with respect to axis x. If the number of through holes 36 in the spring member 30 is set to a common divisor of the number of spring pieces 31, and the number of through holes 29 in the conductive member 20 is set to a common divisor of the number of conductive pieces 21, then regardless of the relative position of the spring member 30 with respect to the conductive member 20 in the direction of axis x, when each of the multiple through holes 36 is superimposed on the multiple through holes 29, each of the multiple spring pieces 31 can be made to contact each of the multiple conductive pieces 21 at a predetermined relative position.

[0065] Furthermore, the multiple through holes 36 are not limited to those having the specific form described above. The multiple through holes 36 are sufficient as long as each of the multiple through holes 36 is superimposed on the multiple through holes 29 of the conductive member 20 when viewed in the axial x direction. Also, when each of the multiple through holes 36 is superimposed on the multiple through holes 29 of the conductive member 20 when viewed in the axial x direction, the multiple spring pieces 31 are sufficient as long as each of the multiple conductive pieces 21 is in contact with the multiple conductive pieces 21 at a predetermined relative position.

[0066] The spring member 30 has the configuration described above, and its inner circumferential end 30a is comb-shaped by a plurality of spring pieces 31. The spring member 30 is integrally formed from an elastic material. That is, the plurality of spring pieces 31 and the base 32 are part of the integrally formed spring member 30, and the plurality of spring pieces 31 and the base 32 are integral. The elastic material forming the spring member 30 is, for example, a metal. The metal forming the spring member 30 is, for example, stainless steel. However, the elastic material forming the spring member 30 is not limited to a metal, and may be, for example, a polymer material.

[0067] As shown in Figures 1-7, the holding member 10 specifically comprises an inner holding member 11 located on the inside and an outer holding member 15 located on the outside. The inner holding member 11 and the outer holding member 15 are annular members around an axis x, and are configured to hold the conductive member 20 and the spring member 30 stacked between them.

[0068] As shown in Figures 1, 3, 4, 6, and 7, the internal retaining member 11 has, for example, a fitting portion 12 which is an annular portion around axis x, and a retaining portion 13 which is an annular portion around axis x. The fitting portion 12 is a cylindrical portion extending along axis x, and the retaining portion 13 is an annular portion extending inward from the front end of the fitting portion 12. The fitting portion 12 is, for example, cylindrical or substantially cylindrical with axis x as its central axis or substantially its central axis.

[0069] As shown in Figures 2, 3, 5-7, the outer retaining member 15 has, for example, a fitting portion 16 which is an annular portion around axis x, and a retaining portion 17 which is an annular portion around axis x. The fitting portion 16 is a cylindrical portion extending along axis x, and the retaining portion 17 is an annular portion extending inward from the front end of the fitting portion 16. The fitting portion 16 is, for example, cylindrical or substantially cylindrical with axis x as its central axis or substantially its central axis.

[0070] As shown in Figures 6 and 7, the inner retaining member 11 and the outer retaining member 15 are designed to be fitted together. Specifically, for example, the diameter of the outer circumferential surface 12a of the fitting portion 12 of the inner retaining member 11 is smaller than the diameter of the inner circumferential surface 16a of the fitting portion 16 of the outer retaining member 15. The fitting portion 12 of the inner retaining member 11 is inserted into the inner circumferential side of the fitting portion 16 of the outer retaining member 15, so that the fitting portion 12 of the inner retaining member 11 and the fitting portion 16 of the outer retaining member 15 are fitted together in a clearance fit. The outer circumferential surface 12a of the fitting portion 12 is an annular surface facing the outer circumferential side of the fitting portion 12, and the inner circumferential surface 16a of the fitting portion 16 is an annular surface facing the inner circumferential side of the fitting portion 16. Furthermore, as shown in Figures 6 and 7, when the fitting portion 12 of the inner retaining member 11 and the fitting portion 16 of the outer retaining member 15 are assembled together, the retaining portion 13 of the inner retaining member 11 and the retaining portion 17 of the outer retaining member 15 have portions that face each other in the axial x direction. The diameter of the outer circumferential surface 12a of the fitting portion 12 of the inner retaining member 11 may be larger than the diameter of the inner circumferential surface 16a of the fitting portion 16 of the outer retaining member 15, and the fitting portion 12 and the fitting portion 16 may be fitted together in an interference fit. Also, the diameter of the outer circumferential surface 12a of the fitting portion 12 and the diameter of the inner circumferential surface 16a of the fitting portion 16 may be the same.

[0071] Also, as shown in FIGS. 6 and 7, in a state where the inner holding member 11 and the outer holding member 15 are combined with each other, the holding portion 13 of the inner holding member 11 and the holding portion 17 of the outer holding member 15 are opposed to the conductive member 20 and the spring member 30 overlapped with each other in the axial direction of the axis x. Specifically, the entire back surface 35 of the base portion 32 of the spring member 30 faces the holding portion 13 of the inner holding member 11, and the entire contact side surface 24 of the base portion 22 of the conductive member 20 faces the holding portion 17 of the outer holding member 15. Further, in the conductive ring 1, as shown in FIGS. 6 and 7, the portion of the conductive piece 21 from the inner peripheral end 21a to a position on the inner peripheral side of the outer peripheral end 21d of each of the plurality of conductive pieces 21 of the conductive member 20 is located on the inner peripheral side of the holding portion 17 of the outer holding member 15, and the portion of the spring piece 31 from the inner peripheral end 31a to a position on the inner peripheral side of the outer peripheral end 31d of each of the plurality of spring pieces 31 of the spring member 30 is located on the inner peripheral side of the holding portion 13 of the inner holding member 11. That is, the inner peripheral end 17a which is the inner peripheral side end of the holding portion 17 is located on the inner peripheral side of the inner peripheral end 22a of the base portion 22 of the conductive member 20 in the radial direction, and the distance R5 which is the distance (radius) from the axis x of the inner peripheral end 17a of the holding portion 17 is smaller than the distance R1 of the inner peripheral end 22a of the base portion 22 of the conductive member 20 (R5 < R1). Also, the inner peripheral end 13a which is the inner peripheral side end of the holding portion 13 is located on the inner peripheral side of the inner peripheral end 32a of the base portion 32 of the spring member 30 in the radial direction, and the distance R6 which is the distance (radius) from the axis x of the inner peripheral end 13a of the holding portion 13 is smaller than the distance R3 of the inner peripheral end 32a of the base portion 32 of the spring member 30 (R6 < R3).

[0072] The position of the inner peripheral end 13a of the holding portion 13 in the radial direction with respect to the conductive piece 21, that is, the relationship between the distance R6 and the distance R2, is related to the magnitude of the pressing force toward the axis x generated by the deformed conductive piece 21 in the usage state of the conductive ring 1. For this reason, the distance R6 of the inner peripheral end 13a of the holding portion 13 is set to a value such that, for example, the pressing force generated by the deformed conductive piece 21 becomes a predetermined magnitude in the usage state of the conductive ring 1.

[0073] Furthermore, the radial position of the inner circumferential end 13a of the retaining portion 13 relative to the spring piece 31, that is, the relationship between distance R6 and distance R4, is related to the magnitude of the pressing force toward axis x generated by the deformed spring piece 31 when the conductive ring 1 is in use. For this reason, the distance R6 of the inner circumferential end 13a of the retaining portion 13 is set to a value such that the pressing force generated by the deformed spring piece 31 is of a predetermined magnitude when the conductive ring 1 is in use.

[0074] The inner circumferential end 17a of the retaining portion 17 may be located at the same position in the radial direction as the inner circumferential end 22a of the base portion 22 of the conductive member 20 (R5=R1). Alternatively, the inner circumferential end 17a of the retaining portion 17 may be located further outward than the inner circumferential end 22a in the radial direction (R5>R1). In this case, a portion of the contact surface 24 of the base portion 22 of the conductive member 20 faces the retaining portion 17. Similarly, the inner circumferential end 13a of the retaining portion 13 may be located at the same position in the radial direction as the inner circumferential end 32a of the base portion 32 of the spring member 30 (R6=R3). Alternatively, the inner circumferential end 13a of the retaining portion 13 may be located further outward than the inner circumferential end 32a in the radial direction (R6>R3). In this case, a portion of the back surface 35 of the base portion 32 of the spring member 30 faces the retaining portion 13.

[0075] Furthermore, the retaining member 10 has a plurality of through holes 19 extending along the axis x. Each of the plurality of through holes 19 is arranged to overlap with the plurality of through holes 29 in the conductive member 20 and the plurality of through holes 36 in the spring member 30 when viewed in the axial x direction. Specifically, as shown in Figures 1 to 5 and 9, the through holes 19 include through holes 19a formed in the retaining portion 13 of the inner retaining member 11 and through holes 19b formed in the retaining portion 17 of the outer retaining member 15, which overlap with each other when viewed in the axial x direction. The retaining portion 13 of the inner retaining member 11 has a plurality of through holes 19a, and the retaining portion 17 of the outer retaining member 15 has a plurality of through holes 19b. The plurality of through holes 19 are provided so that the conductive member 20 and the spring member 30 are held in predetermined relative positions with respect to the retaining member 10.

[0076] Specifically, as shown in Figures 1-5 and 9, each through-hole 19a extends along an axis x3 parallel to axis x and penetrates the holding portion 13 of the internal holding member 11. For example, as shown in Figures 5 and 9, the through-hole 19a is a through-hole with axis x3 as its central axis. Also, for example, the cross-sectional shape of the through-hole 19a perpendicular to axis x3 is the same as or approximately the same as the cross-sectional shape of the through-hole 29 of the conductive member 20 perpendicular to axis x1 or the cross-sectional shape of the through-hole 36 of the spring member 30 perpendicular to axis x2. As an example, the through-hole 19a is a cylindrical or approximately cylindrical through-hole with axis x3 as its central axis, and the cross-section of the through-hole 19a perpendicular to axis x3 is circular or approximately circular, of the same size as or approximately the same size as the cross-section of the through-hole 29 perpendicular to axis x1 and the cross-section of the through-hole 36 perpendicular to axis x2. Furthermore, the through-hole 19a is not limited to a cylindrical through-hole. For example, the shape of the cross-section perpendicular to the axis x3 of the through-hole 19a may be a polygon such as a triangle or rectangle, corresponding to the shape of the through-hole 29 of the conductive member 20 or the shape of the through-hole 36 of the spring member 30, or it may be any other shape. Also, the shape of the cross-section perpendicular to the axis x3 of the through-hole 19a does not have to be the same as the shape of the cross-section perpendicular to the axis x1 of the through-hole 29 of the conductive member 20 or the shape of the cross-section perpendicular to the axis x2 of the through-hole 36 of the spring member 30.

[0077] Furthermore, as shown in Figures 5 and 9, in the internal holding member 11, the multiple through holes 19a are provided, for example, spaced apart from each other around the axis x. Specifically, for example, the multiple through holes 19 are provided at equal or approximately equal angular intervals around the axis x. Also, for example, as shown in Figures 5 and 9, the multiple through holes 19a are provided at the same or approximately the same radial distance from the axis x. Specifically, as shown in Figure 5, the axis x3 of each through hole 19a is provided at a radial distance R9 from the axis x, and in a plane perpendicular to the axis x, the axis x3 of each through hole 19a is located on a circle with radius R9 centered on the axis x. Thus, in the internal holding member 11, the multiple through holes 19a are, as an example, rotationally symmetric or approximately rotationally symmetric with respect to the axis x.

[0078] As described above, each of the multiple through holes 19a in the internal holding member 11 is arranged to overlap with the multiple through holes 29 in the conductive member 20 and the multiple through holes 36 in the spring member 30 when viewed in the axial x direction. For example, each of the multiple through holes 19a is arranged to coincide with or substantially coincide with the multiple through holes 29 and the multiple through holes 36 when viewed in the axial x direction. In this case, as described above, the cross-sectional shape of the through-hole 19a perpendicular to the axis x3 is the same as or approximately the same as the cross-sectional shape of the through-hole 29 of the conductive member 20 perpendicular to the axis x1 and the cross-sectional shape of the through-hole 36 of the spring member 30 perpendicular to the axis x2; the distance R9 of the axis x3 of the through-hole 19a from the axis x is the same as or approximately the same as the distance R7 of the axis x1 of the through-hole 29 from the axis x and the distance R8 of the axis x2 of the through-hole 36 from the axis x; the circumferential spacing between two adjacent through-holes 19a is the same as or approximately the same as the circumferential spacing between two adjacent through-holes 29 and the circumferential spacing between two adjacent through-holes 36; and the number of through-holes 19a is the same as the number of through-holes 29 and through-holes 36.

[0079] As described above, in the internal holding member 11, the axes x3 of the multiple through holes 19a are located on a circle with radius R9. This allows the inner circumferential end 13a of the holding portion 13 of the internal holding member 11 to be positioned at a predetermined relative position with respect to the multiple spring pieces 31 when each of the multiple through holes 19a is superimposed on the multiple through holes 29 and the multiple through holes 36. Furthermore, as described above, the multiple through holes 19a in the internal holding member 11 are rotationally symmetric with respect to axis x, so that each of the multiple through holes 19a can be superimposed on the multiple through holes 29 and the multiple through holes 36 regardless of their relative position with respect to the spring member 30 in the direction of axis x.

[0080] The multiple through holes 19b are formed in the holding portion 17 of the outer holding member 15, similar to the multiple through holes 19a in the inner holding member 11. In other words, each of the multiple through holes 19b is symmetrical or substantially symmetrical to the multiple through holes 19a in the axial x direction.

[0081] In the outer holding member 15, the axes x3 of the multiple through holes 19b are located on a circle with radius R9. This ensures that when each of the multiple through holes 19b is superimposed on the multiple through holes 29 and the multiple through holes 36, the inner circumferential end 17a of the holding portion 17 of the outer holding member 15 is positioned at a predetermined relative position with respect to the multiple conductive pieces 21. Furthermore, as described above, the multiple through holes 19b in the outer holding member 15 are rotationally symmetric with respect to axis x, so that each of the multiple through holes 19b can be superimposed on the multiple through holes 36 and the multiple through holes 29 regardless of their relative position to the conductive member 20 in the direction of axis x.

[0082] The multiple through holes 19a and 19b are not limited to those having the specific forms described above. The multiple through holes 19a and 19b are sufficient if each of them overlaps with the multiple through holes 29 of the conductive member 20 or the multiple through holes 36 of the spring member 30 when viewed in the axial x direction. Furthermore, when each of the multiple through holes 19a is overlapped with the multiple through holes 36 of the spring member 30 when viewed in the axial x direction, the inner circumferential end 13a of the holding portion 13 of the inner holding member 11 contacts the multiple spring pieces 31 at a predetermined relative position. Similarly, when each of the multiple through holes 19b is overlapped with the multiple through holes 29 of the conductive member 20 when viewed in the axial x direction, the inner circumferential end 17a of the holding portion 17 of the outer holding member 15 contacts the multiple conductive pieces 21 at a predetermined relative position.

[0083] As shown in Figures 6 and 7, the inner retaining member 11 and the outer retaining member 15 are combined, and the conductive member 20 and the spring member 30, which are stacked on top of each other, are sandwiched between the retaining portion 13 of the inner retaining member 11 and the retaining portion 17 of the outer retaining member 15 at their respective base portions 22 and 32, and pressed in the axial x direction. A pressing portion 18 is formed on the fitting portion 16 of the outer retaining member 15, and the inner retaining member 11 is fixed to the outer retaining member 15. The pressing portion 18 of the outer retaining member 15 is the part that contacts the fitting portion 12 of the inner retaining member 11 and fixes the fitting portion 12 to the fitting portion 16 in the axial x direction. In this way, the conductive member 20 and the spring member 30, which are stacked on top of each other, are fixed between the inner retaining member 11 and the outer retaining member 15 (hereinafter also referred to as the "assembled state").

[0084] The inner retaining member 11 and the outer retaining member 15 are made of a conductive metal. However, the inner retaining member 11 and the outer retaining member 15 may be made of other conductive materials.

[0085] Each component of the conductive ring 1 has the configuration described above, and when assembled, it becomes the conductive ring 1 shown in Figures 1, 2, 4 to 7. In the conductive ring 1, the fitting portion 12 of the inner holding member 11 is combined with the fitting portion 16 of the outer holding member 15, and the fitting portion 12 of the inner holding member 11 is pressed toward the front by the pressing portion 18 of the fitting portion 16 of the outer holding member 15. The conductive member 20 and the spring member 30, which are stacked on top of each other, are sandwiched between the holding portion 13 of the inner holding member 11 and the holding portion 17 of the outer holding member 15. The conductive member 20 and the spring member 30 are stacked on top of each other such that the pressed side surface 25 of the conductive member 20 is in contact with the pressing side surface 35 of the spring member 30. The conductive member 20 and the spring member 30 are held by the inner holding member 11 and the outer holding member 15 at the base portion 22 and base portion 32, respectively. As described above, the inner retaining member 11 is fixed to the outer retaining member 15, and the conductive member 20 and the spring member 30 are fixed between the inner retaining member 11 and the outer retaining member 15. Furthermore, the conductive member 20 and the spring member 30 are attached to the inner retaining member 11 and the outer retaining member 15, respectively, so that the contact surface 24 of the conductive member 20 contacts the shaft in the usage state described later. Note that, as shown in Figures 1 to 7, the conductive member 20 and the spring member 30 are attached to the inner retaining member 11 and the outer retaining member 15, respectively, so that the contact surface 24 of the conductive member 20 faces the front side. However, the conductive member 20 and the spring member 30 may also be attached to the inner retaining member 11 and the outer retaining member 15, respectively, so that the contact surface 24 of the conductive member 20 faces the back side.

[0086] For example, when the conductive ring 1 is assembled, the multiple through holes 29 of the conductive member 20 and the multiple through holes 36 of the spring member 30 are superimposed on each other when viewed in the axial x direction, so that the conductive member 20 and the spring member 30 are superimposed in the axial x direction. Also, when the conductive ring 1 is assembled, the multiple through holes 19a of the holding portion 13 of the inner holding member 11 and the multiple through holes 36 of the spring member 30 are superimposed on each other when viewed in the axial x direction, and the multiple through holes 19b of the holding portion 17 of the outer holding member 15 and the multiple through holes 29 of the conductive member 20 are superimposed on each other when viewed in the axial x direction, so that the superimposed conductive member 20 and spring member 30 are sandwiched between the holding portion 13 of the inner holding member 11 and the holding portion 17 of the outer holding member 15. As a result, in the assembled conductive ring 1, the multiple conductive pieces 21 and the multiple spring pieces 31 are fixed to each other in predetermined relative positions, the multiple spring pieces 31 and the holding portion 13 of the inner holding member 11 are fixed to each other in predetermined relative positions, and the multiple conductive pieces 21 and the holding portion 17 of the outer holding member 15 are fixed to each other in predetermined relative positions.

[0087] Furthermore, in the assembled conductive ring 1, as described above, the plurality of conductive pieces 21 and the plurality of spring pieces 31 are positioned at predetermined relative positions to each other, and each spring piece 31 is in contact with the corresponding conductive piece 21. Specifically, the pressing surface 34 of each spring piece 31 is in contact with the pressed surface 25 of the corresponding conductive piece 21. Each spring piece 31 extends from the vicinity of the inner circumferential end 22a of the base portion 22 of the conductive member 20, beyond the inner circumferential end 22a, to the corresponding conductive piece 21. As an example, as shown in Figures 1 to 7, the spring piece 31 extends to the vicinity of the outer circumferential end 21d, which is closer to the radial center of the conductive piece 21, and the inner circumferential end 31a of the spring piece 31 is located to the vicinity of the radial center of the conductive piece 21, which is closer to the outer circumferential end 21d. Furthermore, the spring piece 31 is located in the center or approximately the center of the conductive piece 21 in the circumferential direction and is in contact with the center or approximately the center of the conductive piece 21 in the circumferential direction.

[0088] Furthermore, in the assembled conductive ring 1, as described above, the multiple spring pieces 31 and the holding portion 13 of the inner holding member 11 are positioned at predetermined relative positions to each other. Specifically, the radial position of the inner circumferential end 13a of the holding portion 13 relative to each spring piece 31 is predetermined. For example, as shown in Figure 7, the inner circumferential end 13a of the holding portion 13 is located radially on the inner side of the outer circumferential end 31d of the spring piece 31 (R3>R6). Also, in the assembled conductive ring 1, as described above, the multiple conductive pieces 21 and the holding portion 17 of the outer holding member 15 are positioned at predetermined relative positions to each other. Specifically, the radial position of the inner circumferential end 17a of the holding portion 17 relative to each conductive piece 21 is predetermined. For example, as shown in Figure 7, the inner circumferential end 17a of the holding portion 17 is located radially on the inner side of the outer circumferential end 21d of the conductive piece 21 (R1>R5).

[0089] Before reaching the assembled state shown in Figures 1, 2, 4-7, the fitting portion 16 of the outer retaining member 15 does not necessarily have a pressing portion 18. For example, the conductive member 20 and spring member 30, which are superimposed on each other, may be attached to the outer retaining member 15, which does not have a pressing portion 18 formed on the fitting portion 16. After that, the fitting portion 12 of the inner retaining member 11 may be attached to the fitting portion 16 of the outer retaining member 15, and then the pressing portion 18 may be formed on the fitting portion 16. In other words, by forming the pressing portion 18, the fitting portion 12 and the fitting portion 16 are crimped together, and the end of the fitting portion 12 is pressed to the front by the pressing portion 18, thereby assembling the conductive member 20, spring member 30, inner retaining member 11, and outer retaining member 15 as shown in Figures 1-7.

[0090] The clamping allowance δ of the conductive piece 21 is, as shown in Figure 7, the radial width of the conductive piece 21 of the conductive member 20 of the conductive ring 1 in its assembled state, that is, in a free state where no external force is applied to the conductive member 20 and the spring member 30, from the inner circumferential end 21a to a position radially away from the axis x by a distance of radius R0 of the axis 110. When the conductive piece 21 deteriorates due to use in the usage state described later, the conductive piece 21 undergoes plastic deformation, and in a free state where no external force is applied to the conductive member 20 and the spring member 30, the conductive piece 21 becomes curved so that the inner circumferential end 21a is displaced in the axis x direction, and the position of the inner circumferential end 21a of the conductive piece 21 is displaced radially toward the outer circumference. For this reason, when the conductive piece 21 deteriorates and deforms, the clamping allowance δ of the conductive piece 21 decreases.

[0091] Next, the operation of the conductive ring 1 will be described. Figure 11 is a conceptual diagram showing an example of an application for the conductive ring 1. Figure 12 is a cross-sectional view showing an example of the usage state of the conductive ring 1 in the application shown in Figure 11. The conductive ring 1 is applied, as an example, to the drive unit 100 of a battery electric vehicle (BEV), as shown in Figure 11. The drive unit 100 includes, for example, an electric motor 101, a reduction gear 102, an inverter 103 that controls the electric motor 101, and a battery 104 as a power source, as shown in Figure 11. In the electric motor 101, the shaft 110 is rotatably supported by a bearing 112 supported within the housing 111 and exits the housing 111 through a shaft hole 113 in the housing 111. The shaft 110 of the electric motor 101 enters the housing 120 of the reduction gear 102 through a shaft hole 124 in the housing 120 and is rotatably supported by a bearing 123 supported within the housing 120. Furthermore, shaft 110 is connected to a reduction gear stage 121 inside the housing 120. The reducer 102 is also provided with shaft 122, which outputs the rotational driving force reduced by the reduction gear stage 121. Shaft 122 is rotatably supported by a bearing 123 supported inside the housing 120 and is also connected to a wheel 105 so that it can transmit rotational driving force to the wheel 105. An oil seal 125 is installed in the shaft hole 124 of the housing 120 of the reducer 102 to seal the gap between the shaft hole 124 and the shaft 110 of the electric motor 101. An oil seal 127 is installed in the shaft hole 126 of the housing 120 through which the shaft 122 of the reducer 102 passes to seal the gap between the shaft hole 126 and the shaft 122. Note that the shaft 110 and housing 111 of the electric motor 101 are made of metal, and the housing 120 and shaft 122 of the reducer 102 are made of metal.

[0092] The conductive ring 1 is installed, for example, between the housing 111 and the shaft 110 of an electric motor 101, and is in use. Specifically, as shown in Figure 12, the fitting portion 16 of the outer holding member 15 of the holding member 10 is fitted into the shaft hole 113 of the housing 111, fixing the conductive ring 1 in the shaft hole 113, and the shaft 110 is inserted into the conductive member 20, so that the conductive ring 1 is in use. In use, the contact surfaces 24 of the multiple conductive pieces 21 of the conductive member 20 are in contact with the outer circumferential surface 110a of the shaft 110, and the multiple conductive pieces 21 of the conductive member 20 are deformed by being pushed outward by the shaft 110. As shown in Figure 12, the multiple conductive pieces 21 of the conductive member 20 have a width in the axial x direction corresponding to the overlap δ of the conductive pieces 21 and are in contact with the outer circumferential surface 110a of the shaft 110. Furthermore, the retaining members 10 (inner retaining member 11 and outer retaining member 15) to which the conductive member 20 is attached are made of a conductive metal and are in contact with the inner circumferential surface 113a of the shaft hole 113 of the housing 111. In this way, the conductive member 20 and the retaining members 10 form a conductive passage that allows electricity to flow between the shaft 110 of the electric motor 101 and the housing 111 when in use.

[0093] As described above, in the operating state, the multiple conductive pieces 21 of the conductive member 20 are deformed by being pressed outward by the shaft 110. As a result, a reaction force is generated on each of the multiple conductive pieces 21 that presses against the shaft 110, and the multiple conductive pieces 21 generate a tightening force that grips the shaft 110.

[0094] Furthermore, as shown in Figure 12, each of the multiple spring pieces 31 of the spring member 30 overlaps with the multiple conductive pieces 21 of the conductive member 20 from the back side, and the pressing side surface 34 of each spring piece 31 is in contact with the pressed side surface 25 of the corresponding conductive piece 21. As described above, in the operating state, the multiple conductive pieces 21 are deformed by the reaction force from the shaft 110 toward the outer circumference, and each of the multiple spring pieces 31 is also deformed by the force directed toward the outer circumference from the shaft 110 via the corresponding conductive piece 21. Since the multiple spring pieces 31 have elasticity as described above, the multiple spring pieces 31 are elastically deformed, and each spring piece 31 generates a reaction force against the force received from the shaft 110. Due to this reaction force of each spring piece 31, each conductive piece 21 is pressed against the outer circumferential surface 110a of the shaft 110 and pressed toward the shaft 110. In this way, the multiple spring pieces 31 tighten the shaft 110 via the multiple conductive pieces 21, and the multiple spring pieces 31 generate a tightening force that grips the shaft 110.

[0095] Thus, in the operating state, the multiple conductive pieces 21 generate tension, and the multiple spring pieces 31 also generate tension. Therefore, the multiple conductive pieces 21 tighten the shaft 110 not only with the tension they themselves generate, but also with the tension generated by the multiple spring pieces 31. In this way, each of the multiple conductive pieces 21, in cooperation with the spring piece 31 it contacts, generates tension on the shaft 110. As a result, the contact between the multiple conductive pieces 21 and the shaft 110 becomes strong. Furthermore, the conformability of the multiple conductive pieces 21 to the shaft 110 is improved, which also contributes to the strong contact between the multiple conductive pieces 21 and the shaft 110. Therefore, in the conductive ring 1, the contact between the conductive member 20 and the shaft 110 is stable. This makes it possible to maintain or suppress changes in the impedance of the conductive passage formed by the conductive ring 1 between the shaft 110 of the electric motor 101 and the housing 111 over time, thereby making the conductive passage between the shaft 110 of the electric motor 101 and the housing 111 a conductive passage that allows electricity to flow stably.

[0096] Furthermore, the conductive member 20 is made of PTFE resin and is prone to deterioration over time. Therefore, when the conductive ring 1 is in use for the desired usage time, the multiple conductive pieces 21 undergo plastic deformation, and the tension force generated by the reaction force of the multiple conductive pieces 21 decreases. Depending on the length of usage time, the reaction force generated by the multiple conductive pieces 21 may become small, or no reaction force may be generated by the multiple conductive pieces 21 at all. In this case, the tension force generated by the multiple conductive pieces 21 themselves against the shaft 110 becomes small, or the multiple conductive pieces 21 themselves do not generate any tension force against the shaft 110.

[0097] In contrast, the conductive ring 1 has a spring member 30 having multiple spring pieces 31 corresponding to each of the multiple conductive pieces 21. In use, each spring piece 31 presses the corresponding conductive piece 21 against the shaft 110, and the tension generated by the multiple spring pieces 31 tightens the multiple conductive pieces 21 against the shaft 110. Therefore, even if the tension generated by the multiple conductive pieces 21 themselves against the shaft 110 decreases over time in use, or even if the tension generated by the multiple conductive pieces 21 themselves against the shaft 110 disappears, the tension generated by the multiple spring pieces 31 allows the multiple conductive pieces 21 to continue tightening the shaft 110, thus maintaining or suppressing the decrease in tension of the multiple conductive pieces 21 against the shaft 110. Therefore, the impedance of the conductive passage formed by the conductive ring 1 can be maintained or changes in impedance can be suppressed over time, and the conductive passage formed by the conductive ring 1 can be made into a conductive passage that allows electricity to flow stably.

[0098] Furthermore, the inner circumferential end portion 20a of the conductive member 20 is made up of multiple conductive pieces 21 that are spaced apart from each other in the circumferential direction. Therefore, in the operating state, the multiple conductive pieces 21 come into contact with the shaft 110, and each of the multiple conductive pieces 21 deforms. In this way, the circumferential restraining force of each conductive piece 21 is reduced, and the magnitude of the tension force generated by the multiple conductive pieces 21 themselves can be reduced. As a result, wear of the multiple conductive pieces 21 caused by the rotation of the shaft 110 can be suppressed.

[0099] Furthermore, the conductive ring 1 may be provided between the housing 120 and the shaft 122 of the reduction gear 102. Specifically, as shown in Figure 11, the conductive ring 1 may be provided outside the oil seal 127 in the gap between the shaft hole 126 of the housing 120 and the shaft 122. In this case as well, similar to the conductive ring 1 attached to the electric motor 101, the conductive member 20 and the retaining member 10 of the conductive ring 1 form a conductive passage for electricity to flow between the shaft 122 of the reduction gear 102 and the housing 120. The conductive ring 1 may be used in oil, or it may be provided inside the oil seal 127.

[0100] The above-described drive unit 100 is just one example of an application for the conductive ring 1, and its application is not limited to this. The conductive ring 1 is used, for example, in drive units of electric vehicles (EVs) such as battery electric vehicles (BEVs), hybrid vehicles (HVs), and fuel cell vehicles (FCVs). In vehicles equipped with electric motors such as electric vehicles (EVs), the shafts 110 and 120 may become charged due to induced currents generated from the motor, generating electromagnetic noise. In addition, the shafts 110 and 122 may become charged due to the on / off operation of the inverter for current control supplied to the electric motor, or due to the induced voltage of the electric motor itself, generating electromagnetic noise. As described above, the conductive ring 1 forms a conductive passage and allows the voltage charged on the shafts 110 and 122 to flow to the housings 111 and 122. This prevents communication failures and malfunctions in electronic equipment, and prevents electrolytic corrosion in metal parts such as bearings.

[0101] As described above, the conductive ring 1 according to the embodiment of the present invention can suppress a decrease in tension on the shaft 110.

[0102] Furthermore, as described above, by overlapping the multiple through holes 29 of the conductive member 20 and the multiple through holes 36 of the spring member 30 in the axial x direction, and overlapping the conductive member 20 and the spring member 30 in the axial x direction, the multiple conductive pieces 21 and the multiple spring pieces 31 can be positioned relative to each other at predetermined positions. In this way, the multiple conductive pieces 21 and the multiple spring pieces 31 can be easily positioned relative to each other at predetermined positions.

[0103] Furthermore, as described above, by overlapping the multiple through holes 19a of the holding portion 13 of the inner holding member 11 and the multiple through holes 36 of the spring member 30 when viewed in the axial x direction, and by overlapping the multiple through holes 19b of the holding portion 17 of the outer holding member 15 and the multiple through holes 29 of the conductive member 20 when viewed in the axial x direction, and by sandwiching the overlapping conductive member 20 and spring member 30 between the holding portion 13 of the inner holding member 11 and the holding portion 17 of the outer holding member 15, the multiple spring pieces 31 and the holding portion 13 of the inner holding member 11 can be positioned relative to each other at predetermined positions, and the multiple conductive pieces 21 and the holding portion 17 of the outer holding member 15 can be positioned relative to each other at predetermined positions. In this way, the multiple spring pieces 31 and the holding portion 13 of the inner holding member 11 can be easily positioned relative to each other at predetermined positions, and the multiple conductive pieces 21 and the holding portion 17 of the outer holding member 15 can be easily positioned relative to each other at predetermined positions.

[0104] Thus, with the conductive ring 1, the conductive ring 1 can be easily assembled in a way that suppresses a decrease in tension on the shaft 110 by overlapping the multiple through holes 29 of the conductive member 20, the multiple through holes 36 of the spring member 30, and the multiple through holes 19 (19a, 19b) of the holding member 10 with each other when viewed in the axial x direction, and assembling the conductive member 20, spring member 30, inner holding member 11, and outer holding member 15.

[0105] For example, a jig is prepared having a pin that can be inserted without gaps or with gaps into the through-hole 29 of the conductive member 20, the through-hole 36 of the spring member 30, and the through-hole 19 (19a, 19b) of the retaining member 10. By passing the pin of this jig through the through-hole 19a of the inner retaining member 11, the through-hole 36 of the spring member 30, the through-hole 29 of the conductive member 20, and the through-hole 19b of the outer retaining member 15 in this order, the inner retaining member 11, the spring member 30, the conductive member 20, and the outer retaining member 15 can be positioned relative to each other in predetermined positions. Alternatively, the pin of the jig may be passed through the through-hole 19b of the outer retaining member 15, the through-hole 29 of the conductive member 20, the through-hole 36 of the spring member 30, and the through-hole 19a of the inner retaining member 11. Furthermore, the jig may have one or more of the above-mentioned pins.

[0106] Furthermore, the through-holes 29 in the conductive member 20, 36 in the spring member 30, and 19 (19a, 19b) in the retaining member 10 allow for weight reduction of the conductive member 20, spring member 30, and retaining member 10, respectively. This makes the conductive ring 1 lighter.

[0107] Furthermore, when the conductive ring 1 is used in oil, the multiple through holes 29, 36, and 19 of the conductive ring 1 pass through the conductive ring 1, allowing oil to pass through. Therefore, the flow path of the oil is not blocked by the conductive ring 1. This makes it possible to suppress or prevent a decrease in lubrication performance or cooling performance caused by the installation of the conductive ring 1.

[0108] Next, a modified example of the conductive member 20 will be described. Figure 13 is a front view of conductive member 20A, which is an example of a modified example of the conductive member 20. Hereinafter, regarding the configuration of conductive member 20A, components that are the same as or have the same function as conductive member 20 described above will be denoted by the same reference numerals and their descriptions will be omitted, while components that differ from conductive member 20 will be described.

[0109] As shown in Figure 13, the conductive member 20A has a gap 27 that extends in at least one radial direction and a conductive member piece 26 that extends around at least one axis x. The conductive member piece 26 has a pair of ends 28a, 28b in the direction of axis x. The gap 27 is connected to the ends 28a, 28b of the conductive member piece 26.

[0110] As shown in Figure 13, the conductive member 20A is an annular plate-shaped structure composed of, for example, two gaps 27 (gaps 27A, 27B) and two conductive member pieces 26 (conductive member pieces 26A, 26B). As shown in Figure 13, the conductive member piece 26A has a pair of ends 28Aa, 28Ab, and the conductive member piece 26B has a pair of ends 28Ba, 28Bb. One of the pair of ends (end 28Aa) of one conductive member piece 26 (conductive member piece 26A) and one of the pair of ends (28Ba) of the other conductive member piece 26 (conductive member piece 26B) face each other in the direction around the axis x (circumferential direction). Furthermore, the other end of the pair of conductive member pieces 26A (end 28Ab) and the other end of the pair of conductive member pieces 26B (end 28Bb) face each other in the direction around the axis x (circumferential direction). One side of the gap 27 (gap 27A) is formed between end 28Aa of conductive member piece 26A and end 28Ba of conductive member piece 26B, and the other side of the gap 27 (gap 27B) is formed between end 28Ab of conductive member piece 26A and end 28Bb of conductive member piece 26B.

[0111] The conductive member pieces 26A and 26B are members that correspond to a part of the conductive member 20 of the conductive ring 1 shown in Figures 1 to 9, and coincide with or substantially coincide with a part of the conductive member 20. The conductive member pieces 26A and 26B are formed, for example, by dividing the conductive member 20, as shown in Figures 1 to 9, to form gaps 27A and 27B. Therefore, the cross-sectional shape of the conductive member pieces 26A and 26B in a plane containing axis x is the same as the cross-sectional shape of the conductive member 20 shown in Figure 13. Conductive member pieces 26A and 26B are, for example, the same. However, conductive member pieces 26A and 26B do not have to be the same. The conductive member pieces 26A and 26B extend along a circular arc or substantially circular arc centered on axis x, for example, as shown in Figure 13. Specifically, as shown in Figure 13, for example, the conductive member pieces 26A and 26B extend in the circumferential direction such that their length is shorter than the semicircle of the circle along which they extend.

[0112] In the conductive ring 1, the conductive member 20A is provided in the same way as the conductive member 20. That is, the conductive member piece 26A is superimposed on the spring member 30 in the same way as the corresponding part of the conductive member 20 of the conductive member piece 26A. Multiple conductive pieces 21 of the conductive member piece 26A are in contact with multiple corresponding spring pieces 31 of the spring member 30. Similarly, multiple conductive pieces 21 of the conductive member piece 26B are in contact with multiple corresponding spring pieces 31 of the spring member 30. In addition, there are two gaps 27A and 27B interposed between the conductive member pieces 26A and 26B superimposed on the spring member 30. Specifically, gap 27A is interposed between the end 28Aa of the conductive member piece 26A and the end 28Ba of the conductive member piece 26B, and gap 27B is interposed between the end 28Ab of the conductive member piece 26A and the end 28Bb of the conductive member piece 26B. Thus, the gap 27A is connected to the end 28Aa of the conductive member piece 26A and the end 28Ba of the conductive member piece 26B, and the gap 27B is connected to the end 28Ab of the conductive member piece 26A and the end 28Bb of the conductive member piece 26B.

[0113] The conductive ring 1 having the modified conductive member 20A is used in the same way as the conductive ring 1 described above to form a conductive passage between the shaft 110 of the electric motor 101 and the housing 111. Furthermore, the conductive member 20A in the modified form acts in the same way as the conductive ring 1 described above and produces the same effect.

[0114] Furthermore, in the conductive ring 1 having the conductive member 20A according to the modified example, the conductive member pieces 26A and 26B are arranged in a ring shape with gaps 27A and 27B in between. Therefore, even if an external force is applied to the conductive member pieces 26A and 26B due to the rotation of the shaft 110 during use, the conductive member pieces 26A and 26B can escape into the gaps 27A and 27B. This prevents deformation that would cause stress concentration in the conductive member pieces 26A and 26B, as well as contact with the shaft 110. This makes it possible to suppress wear and deterioration of the conductive member pieces 26A and 26B.

[0115] Furthermore, when fixing the conductive member pieces 26A and 26B to the holding member 10, the conductive member pieces 26A and 26B can escape into the gaps 27A and 27B. This prevents deformation such as wrinkling from occurring in the conductive member pieces 26A and 26B when fixing them to the holding member 10.

[0116] In the conductive ring 1 having the conductive member 20A according to the modified example, similar to the conductive ring 1 described above, the conductive ring 1 can be easily assembled in a way that suppresses a decrease in tension on the shaft 110 by overlapping the multiple through holes 29 of the conductive member pieces 26A and 26B, the multiple through holes 36 of the spring member 30, and the multiple through holes 19 (19a, 19b) of the holding member 10 with each other when viewed in the axial x direction, and assembling the conductive member pieces 26A and 26B, the spring member 30, the inner holding member 11, and the outer holding member 15.

[0117] The above-described jig can also be used in the conductive ring 1 having the conductive member 20A according to the modified example. However, in this case, the jig has the above-described pins for each of the conductive member pieces 26A and 26B. The pins for conductive member piece 26A and conductive member piece 26B are positioned in the jig so that the conductive member pieces 26A and 26B are arranged in a ring shape and are in the positions on the conductive ring 1. The jig may have one or more pins for conductive member piece 26A. Similarly, the jig may have one or more pins for conductive member piece 26B.

[0118] Next, other modifications of the conductive member 20 will be described. Figure 14 is a front view of conductive member 20B as another example of a modification of conductive member 20. As shown in Figure 11, conductive member 20B according to the other modification has one conductive member piece 26C as conductive member piece 26 and one gap 27C as gap 27. In conductive member 20B, one of the gaps 27A or gap 27B is absent, and conductive member piece 26A or conductive member piece 26B extends into one portion of gap 27A or gap 27B, and conductive member piece 26A and conductive member piece 26B are connected in one portion of gap 27A or gap 27B to form one conductive member piece 26C. The conductive member piece 26C of the conductive member 20B extends, for example, on a circle or approximately circle with axis x as its center or approximate center, as shown in Figure 14, and its ends 28Ca and 28Cb face each other in the circumferential direction, specifically, for example, in a direction perpendicular to axis x. The conductive member piece 26C has a conductive member piece 20C that corresponds to a part of the conductive member 20, similar to the conductive member pieces 26A and 26B. The conductive member 20 may have three or more gaps 27 and three or more conductive member pieces 26. In this case as well, the multiple gaps 27 and the multiple conductive member pieces 26 are connected in an annular shape.

[0119] In the conductive ring 1 having a conductive member 20B according to other modifications, the conductive ring 1 can be easily assembled in a manner that suppresses a decrease in tension on the shaft 110 by overlapping the multiple through holes 29 of the conductive member 20B, the multiple through holes 36 of the spring member 30, and the multiple through holes 19 (19a, 19b) of the holding member 10 with each other when viewed in the x-axis direction, and assembling the conductive member 20B, spring member 30, inner holding member 11, and outer holding member 15. The jig described above can also be used in the conductive ring 1 having a conductive member 20B according to other modifications.

[0120] Next, a modified example of the spring member 30 will be described. The spring member 30 may also be modified in the same way as the conductive member 20 described above. Figure 15 is a front view of spring member 30A as an example of a modified example of spring member 30. Hereinafter, regarding the configuration of spring member 30A, the same reference numerals are used for configurations that are the same as or have the same function as spring member 30 described above, and their descriptions are omitted. Configurations that are different from spring member 30 will be described.

[0121] As shown in Figure 15, the spring member 30A has a gap 38 that extends in at least one radial direction and a spring member piece 37 that extends around at least one axis x. The spring member piece 37 has a pair of ends 39a, 39b in the direction of axis x. The gap 38 is connected to the ends 39a, 39b of the spring member piece 37.

[0122] As shown in Figure 15, the spring member 30A is an annular plate-shaped structure composed of, for example, two gaps 38 (gaps 38A, 38B) and two spring member pieces 37 (spring member pieces 37A, 37B). As shown in Figure 15, the spring member piece 37A has a pair of ends 39Aa, 39Ab, and the spring member piece 37B has a pair of ends 39Ba, 39Bb. One of the pair of ends of one of the spring member pieces 37 (spring member piece 37A) (end 39Aa) and one of the pair of ends of the other of the spring member piece 37 (spring member piece 37B) (end 39Ba) are opposite each other in the direction around the axis x (circumferential direction). Furthermore, the other end of the pair of ends of spring member piece 37A (end 39Ab) and the other end of the pair of ends of spring member piece 37B (end 39Bb) face each other in the direction around axis x (circumferential direction). One side of the gap 38 (gap 38A) is formed between end 39Aa of spring member piece 37A and end 39Ba of spring member piece 37B, and the other side of the gap 38 (gap 38B) is formed between end 39Ab of spring member piece 37A and end 39Bb of spring member piece 37B. For example, spring member pieces 37A and 37B extend around axis x to the same or approximately the same length as conductive member pieces 26A and 26B. In other words, spring member piece 37A and conductive member piece 26A can be superimposed on each other by aligning or approximately aligning their ends 38Aa and 28Aa, and their ends 39Ab and 28Ab, respectively, in the direction of axis x. Similarly, the spring member piece 37B and the conductive member piece 26B can be superimposed on each other by aligning their ends 39Ba and 28Ba, and their ends 39Bb and 28Bb, respectively, in the x-axis direction.

[0123] The spring member pieces 37A and 37B are members that correspond to a part of the spring member 30 of the conductive ring 1 shown in Figures 1-7, 9, and 10, and coincide with or substantially coincide with a part of the spring member 30. The spring member pieces 37A and 37B are formed, for example, by dividing the spring member 30, as shown in Figures 1-7, 9, and 10, to form gaps 38A and 38B. Therefore, the cross-sectional shape of the spring member pieces 37A and 37B in a plane containing the axis x is the same as the cross-sectional shape of the spring member 40 shown in Figure 15. The spring member pieces 37A and 37B are, for example, the same. However, the spring member pieces 37A and 37B do not have to be the same. The spring member pieces 37A and 37B extend along a circular arc or substantially circular arc centered on the axis x, for example, as shown in Figure 15. Specifically, as shown in Figure 15, for example, the spring member pieces 37A and 37B extend in the circumferential direction such that they are shorter than the semicircle of the circle along which they extend.

[0124] In the conductive ring 1, the spring member 30A is provided in the same way as the spring member 30. That is, the spring member piece 37A is superimposed on the conductive members 20, 20A, and 20B in the same way as the corresponding part of the spring member 30 of the spring member piece 37A. Multiple spring pieces 31 of the spring member piece 36A are in contact with multiple corresponding conductive pieces 21 of the conductive members 20, 20A, and 20B. Similarly, multiple spring pieces 31 of the spring member piece 37B are in contact with multiple corresponding conductive pieces 21 of the conductive members 20, 20A, and 20B. In addition, two gaps 38A and 38B are interposed between the spring member piece 37A and the spring member piece 37B that are superimposed on the conductive members 20, 20A, and 20B. Specifically, a gap 38A is interposed between the end 39Aa of spring member piece 37A and the end 39Ba of spring member piece 37B, and a gap 38B is interposed between the end 39Ab of spring member piece 37A and the end 39Bb of spring member piece 37B. Thus, gap 38A is connected to the end 39Aa of spring member piece 37A and the end 39Ba of spring member piece 37B, and gap 38B is connected to the end 39Ab of spring member piece 37A and the end 39Bb of spring member piece 37B.

[0125] The conductive ring 1 having the modified spring member 30A is used in the same way as the conductive ring 1 described above to form a conductive passage between the shaft 110 of the electric motor 101 and the housing 111. Furthermore, the modified spring member 30A also acts in the same way as the conductive ring 1 described above and produces the same effect.

[0126] Furthermore, in the conductive ring 1 having a modified spring member 30A, the spring member pieces 37A and 37B are arranged in an annular shape with gaps 38A and 38B in between. Therefore, even if an external force is applied to the spring member pieces 37A and 37B due to the rotation of the shaft 110 during use, the spring member pieces 37A and 37B can escape into the gaps 38A and 38B. This prevents deformation that would cause stress concentration in the spring member pieces 37A and 37B, as well as contact with the shaft 110. As a result, damage to the spring member pieces 37A and 37B can be suppressed.

[0127] Furthermore, when fixing the spring member pieces 37A and 37B to the retaining member 10, the spring member pieces 37A and 37B can escape into the gaps 38A and 38B. This prevents deformation such as wrinkling from occurring in the spring member pieces 37A and 37B when they are fixed to the retaining member 10.

[0128] Next, other modifications of the spring member 30 will be described. Figure 16 is a front view of spring member 30B as another example of a modification of spring member 30. As shown in Figure 16, the spring member 30B according to the other modification has one spring member piece 37C as a spring member piece 37 and one gap 38C as a gap 38. In spring member 30B, one of the gaps 38A or 38B is absent, and the spring member piece 37A or 37B extends into one portion of the gap 38A or 38B, and the spring member piece 37A and the spring member piece 37B are connected in one portion of the gap 38A or 38B to form one spring member piece 37C. As shown in Figure 16, the spring member piece 37C of the spring member 30B extends on a circle or approximately circle with axis x as its center or approximately center, and the ends 39Ca and 39Cb face each other in the circumferential direction, specifically, for example, in a direction perpendicular to axis x. The spring member piece 37C, like the spring member pieces 37A and 37B, has a spring member piece 37C that corresponds to a part of the spring member 30. For example, the spring member piece 37C extends around axis x for the same or approximately the same length as the conductive member piece 26C. In other words, the spring member piece 37C and the conductive member piece 26C can be superimposed on each other by aligning or approximately aligning the ends 39Ca and 28Ca when viewed in the direction of axis x. The spring member 30 may have three or more gaps 38 and three or more spring member pieces 37. In this case as well, the multiple gaps 38 and the multiple spring member pieces 37 are connected in an annular shape.

[0129] Although the present invention has been described above through the embodiments described above, the technical scope of the present invention is not limited to the scope described in the embodiments above. It will be obvious to those skilled in the art that various modifications or improvements can be made to the embodiments described above. It will be clear from the claims that such modified or improved forms may also be included in the technical scope of the present invention.

[0130] The embodiments described above are for the purpose of facilitating understanding of the present invention and are not intended to limit its interpretation. Furthermore, the embodiments described above do not limit the scope of application of the present invention, and the present invention may encompass anything as its target application. The components of the above embodiments, as well as their arrangement, materials, conditions, shapes, and sizes, are not limited to those exemplified and can be modified as appropriate. For example, the present invention includes differences that arise in the implementation of manufacturing tolerances, etc. Furthermore, components shown in different embodiments can be partially substituted or combined to the extent that they do not contradict each other in a technical sense. In addition, each configuration can be selectively combined as appropriate to achieve at least some of the problems and effects described above. [Explanation of symbols]

[0131] 1 Conductive ring, 10 Retaining member, 11 Inner retaining member, 12 Fitting part, 12a Outer surface, 13 Retaining part, 13a Inner end, 15 Outer retaining member, 16 Fitting part, 16a Inner surface, 17 Retaining part, 17a Inner end, 18 Pressing part, 19, 19a, 19b Through hole, 20, 20A, 20B Conductive member, 20a Inner end, 21 Conductive piece (end piece), 21a Inner end, 21b, 21c Side end, 21d Outer end, 22 Base, 22a Inner end, 22b Outer end, 23 Gap, 24 Contact side, 25 Pressed side, 26, 26A, 26B, 26C Conductive member piece, 27, 27A, 27B, 27C Gap, 28a, 28Aa, 28Ba, 28Ca, 28b, 28Ab, 28Bb, 28Cb End, 29 Through hole, 30 Spring member, 30a Inner circumference end, 31 Spring piece (end piece), 31a Inner circumference end, 31b, 31c Side end, 31d Outer circumference end, 32 Base, 32a Inner circumference end, 32b Outer circumference end, 33 Space, 34 Pressing side, 35 Back, 36 Through hole, 37, 37A, 37B, 37C Conductive member piece, 38, 38A, 38B, 38C Gap, 39a, 39Aa, 39Ba, 39Ca, 39b, 39Ab, 39Bb, 39Cb End, 100, 200 Drive device, 101 Electric motor, 102 Reducer, 103 Inverter, 104 Battery, 105 Wheels, 110,122 Axle, 110a,122a Outer surface, 111,120 Housing, 121 Reduction gear stage, 112,123 Bearing, 113,124,126 Axle hole, 113a,124a,126a Inner surface, 125,127 Oil seal, L1,L2 Length, R0 Radius, R1,R2,R3,R4,R5,R6,R7,R8,R9 Distance (radius), T1,T2 Thickness, W1,W2,W3,W4 Width, x,x1,x2,x3 Axis, y1,y2 Radial line, δ Interlocking allowance

Claims

1. A method for assembling a conductive ring, Using a jig having at least one pin, The aforementioned conductive ring is A retaining member which is an annular conductive member around the axis, A conductive member which is a conductive member extending around the aforementioned axis, It comprises a spring member extending around the aforementioned axis, The conductive member has a plurality of end pieces arranged in the circumferential direction at its inner circumference end, and also has a plurality of through holes extending along the axis. The spring member has a plurality of end pieces arranged in the circumferential direction at its inner end, and also has a plurality of through holes extending along the axis. Each of the multiple end pieces of the spring member is designed to elastically deform along the axis and to contact the multiple end pieces of the conductive member. The holding member is configured to hold the conductive member and the spring member side by side in the axial direction. The plurality of through holes in the conductive member and the plurality of through holes in the spring member are arranged to overlap each other when viewed in the axial direction. When the plurality of through holes in the conductive member and the plurality of through holes in the spring member overlap each other in the axial direction, the plurality of end pieces of the spring member each come into contact with the plurality of end pieces of the conductive member. At least one pin of the jig is insertable into any of the plurality of through holes in the conductive member and any of the plurality of through holes in the spring member. The pin of the jig is inserted into the through hole of the conductive member and the through hole of the spring member, so that the conductive member and the spring member are superimposed in the axial direction, and the spring member is positioned relative to the conductive member. How to assemble a conductive ring.

2. In the conductive member, the plurality of through holes are provided at positions corresponding to the positions of the plurality of end pieces. In the spring member, the plurality of through holes are provided at positions corresponding to the positions of the plurality of end pieces. A method for assembling a conductive ring according to claim 1.

3. In the conductive member, the number of through holes corresponds to the number of end pieces. In the spring member, the number of through holes corresponds to the number of end pieces. A method for assembling a conductive ring according to claim 1.

4. In the conductive member, the plurality of through holes are provided spaced apart from each other around the axis. In the spring member, the plurality of through holes are provided spaced apart from each other around the axis. A method for assembling a conductive ring according to claim 1.

5. The retaining member has a plurality of through holes extending along the axis, The plurality of through holes in the holding member are arranged to overlap with the plurality of through holes in the conductive member and the plurality of through holes in the spring member when viewed in the axial direction. The pin of the jig is inserted into the through hole of the conductive member, the through hole of the spring member, and the through hole of the retaining member, thereby overlapping the conductive member, the spring member, and the retaining member in the axial direction, and positioning the spring member, the conductive member, and the retaining member relative to each other. A method for assembling a conductive ring according to claim 1.

6. The circumferential width of the end piece of the spring member is less than or equal to the circumferential width of the end piece of the conductive member. A method for assembling a conductive ring according to claim 1.

7. The outer peripheral ends of the plurality of end pieces of the spring member are positioned further outward than the outer peripheral ends of the plurality of end pieces of the conductive member. When the plurality of through holes in the conductive member and the plurality of through holes in the spring member overlap each other in the axial direction, the outer peripheral ends of the plurality of end pieces of the spring member are located further outward than the outer peripheral ends of the plurality of end pieces of the conductive member. A method for assembling a conductive ring according to claim 1.

8. The spring member has a base portion which is an annular part, The plurality of end pieces of the spring member extend inward from the inner circumference end of the base of the spring member, The plurality of through holes in the spring member are provided in the base portion. A method for assembling a conductive ring according to claim 1.

9. The conductive member has a base portion which is an annular part, The plurality of end pieces of the conductive member extend inward from the inner circumferential end of the base of the conductive member, The plurality of through holes in the conductive member are provided in the base portion. A method for assembling a conductive ring according to claim 1.

10. The number of the plurality of end pieces of the spring member is the same as the number of the plurality of end pieces of the conductive member. A method for assembling a conductive ring according to claim 1.

11. The holding member is configured to hold the conductive member and the spring member on their outer circumference. A method for assembling a conductive ring according to claim 1.

12. The conductive member is formed from conductive PTFE having electrical conductivity. A method for assembling a conductive ring according to claim 1.

13. The retaining member comprises an inner retaining member which is an annular member around the axis and an outer retaining member which is an annular member around the axis. The internal retaining member has the plurality of through holes in the retaining member, The outer retaining member has the plurality of through holes in the retaining member, The inner holding member and the outer holding member are combined with each other to be able to hold the conductive member and the spring member. The pins of the jig are inserted sequentially into the through holes of the outer retaining member, the conductive member, the spring member, and the inner retaining member, or sequentially into the through holes of the inner retaining member, the spring member, the conductive member, and the outer retaining member, so that the outer retaining member, the conductive member, the spring member, and the inner retaining member are aligned in the axial direction, thereby positioning the outer retaining member, the conductive member, the spring member, and the inner retaining member relative to each other. The method for assembling a conductive ring according to claim 5.

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