Conductive ring

Abstract

Provided is a conductive ring capable of suppressing a decrease in the tightening force with respect to the shaft. 【Solution means】 The conductive ring 1 includes an annular conductive holding member 10, a conductive member 20 having conductivity extending around the axis x, and a spring member 30 having conductivity extending around the axis x. The conductive member 20 has a plurality of conductive pieces 21 arranged in the circumferential direction at the inner peripheral end portion 20a. The spring member 30 has a plurality of spring pieces 31 arranged in the circumferential direction at the inner peripheral end portion 30a. Each of the plurality of 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 axis x direction.

Description

Technical Field

[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 the operation of the inverter, 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, such charging of the rotating shaft may cause electrolytic corrosion of metal parts such as bearings. For this reason, conventionally, measures have been taken to remove 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 the housing of a motor, 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 the conductive ring slides with respect to the rotating shaft, conventionally, a configuration that has conductivity and is wear-resistant has been required for the conductive member. For example, in Patent Document 1, it has been proposed to make the conductive member of conductive PTFE. Due to the characteristics of PTFE, the pressing force of the conductive member made of conductive PTFE against the rotating shaft is strong at the initial stage of use and greatly decreases over time. For this reason, the pressing force of the conventional conductive member made of conductive PTFE against the rotating shaft greatly decreases after use for a desired period of time, and in many cases, it almost disappears. For this reason, the conductivity of the conventional conductive member made of conductive PTFE has greatly decreased after use for a desired period of time. Thus, a configuration that can prevent a decrease in the pressing force against the rotating shaft has been required for the conventional conductive ring.

[0005] The present invention has been made in view of the above problems, and an object thereof is to provide a conductive ring capable of suppressing a decrease in the pressing force against the shaft.

Means for Solving the Problems

[0006] To achieve the above object, the conductive ring according to the present invention includes a holding member that is a member having annular conductivity around an axis, a conductive member that is a member having conductivity extending around the axis, and a spring member extending around the axis. The conductive member has a plurality of end pieces arranged in the circumferential direction at an end portion on the inner peripheral side. The spring member has a plurality of end pieces arranged in the circumferential direction at an end portion on the inner peripheral side. The plurality of end pieces of the spring member are each configured to elastically deform along the axis and also to contact the plurality of end pieces of the conductive member. The holding member holds the conductive member and the spring member side by side in the axial direction.

[0007] In the conductive ring according to one aspect of the present invention, the plurality of end pieces of the spring member are arranged at intervals in the circumferential direction.

[0008] In the conductive ring according to one aspect of the present invention, the circumferential width of the end piece of the spring member is equal to or less than the circumferential width of the end piece of the conductive member.

[0009] In the conductive ring according to one aspect of the present invention, the outer peripheral side ends of the plurality of end pieces of the spring member are positioned more on the outer peripheral side than the outer peripheral side ends of the plurality of end pieces of the conductive member.

[0010] In the conductive ring according to one aspect of the present invention, the spring member has a base portion which is an annular portion, and the plurality of end pieces of the spring member extend inward from the inner peripheral side end of the base portion of the spring member.

[0011] In the conductive ring according to one aspect of the present invention, the plurality of end pieces of the conductive member are arranged at intervals in the circumferential direction.

[0012] In the conductive ring according to one aspect of the present invention, the conductive member has a base portion which is an annular portion, and the plurality of end pieces of the conductive member extend inward from the inner peripheral side end of the base portion of the conductive member.

[0013] 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.

[0014] In the conductive ring according to one aspect of the present invention, the holding member holds the conductive member and the spring member on the outer peripheral side.

[0015] 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

[0016] 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

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

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Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

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Figure 15

Embodiments for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, not all of the plurality of components are labeled, and the labels of some of the plurality of components may be omitted.

[0019] The conductive ring according to an embodiment of the present invention forms a conductive path on a rotating shaft. For example, a conductive path is formed between the shaft and a hole through which the shaft is inserted. Note that the application target to which the conductive ring according to the embodiment of the present invention is applied is not limited to this. FIGS. 1 and 2 are perspective views showing a schematic configuration of the conductive ring 1 according to the embodiment of the present invention, and FIG. 3 is an exploded perspective view of the conductive ring 1. Further, FIG. 4 is a front view of the conductive ring 1, and FIG. 5 is a rear view of the conductive ring 1. Also, FIG. 6 is a cross-sectional view showing a cross-section by a plane including the axis x of the conductive ring 1, and FIG. 7 is a cross-sectional view showing one side with respect to the axis x of the conductive ring 1 shown in FIG. 6. Note that FIG. 1 is a perspective view of the conductive ring 1 viewed from the front side, and FIG. 2 is a perspective view of the conductive ring 1 viewed from the rear side.

[0020] As shown in FIGS. 1 to 7, the conductive ring 1 includes a holding member 10 which is a member having annular conductivity around the axis x, a conductive member 20 which is a member having conductivity extending around the axis x, and a spring member 30 which extends around the axis x. The conductive member 20 has conductive pieces 21 which are a plurality of end pieces arranged in the circumferential direction at an inner circumferential end 20a which is an end on the inner circumferential side. The spring member 30 has spring pieces 31 which are a plurality of end pieces arranged in the circumferential direction at an inner circumferential end 30a which is an end on the inner circumferential side. The plurality of spring pieces 31 of the spring member 30 are each adapted to elastically deform along the axis x and also to contact the plurality of conductive pieces 21 of the conductive member 20. The holding member 10 is adapted to hold the conductive member 20 and the spring member 30 side by side in the direction of the axis x. Hereinafter, the configuration of the conductive ring 1 will be specifically described. Note that the inner circumferential side is the side closer to the axis x in the direction orthogonal to the axis x (hereinafter also referred to as the radial direction), and the outer circumferential side is the side away from the axis x in the radial direction.

[0021] The conductive member 20 is, for example, an annular plate-like member around the axis x as shown in FIGS. 1 to 7, and has a contact side surface 24 and a pressed side surface 25 which are a pair of annular surfaces facing away from each other in the axis x direction. As shown in FIGS. 6 and 7, the contact side surface 24 faces one side (front side) in the axis x direction, and the pressed side surface 25 faces the other side (rear side) in the axis x direction. As described above, the conductive member 20 has a plurality of conductive pieces 21 at an inner peripheral end portion 20a which is an end portion on the inner peripheral side, and also has a base portion 22 which is an annular portion. The base portion 22 is a portion on the outer peripheral side of the conductive pieces 21 in the conductive member 20 as shown in FIGS. 6 and 7. A plurality of conductive pieces 21 extend from an inner peripheral end 22a which is an inner peripheral side end of the base portion 22 toward the inner peripheral side. The base portion 22 is, for example, an annular plate-like portion around the axis x as shown in FIGS. 3, 6, and 7, and the inner peripheral end 22a extends, for example, along a cylindrical surface centered on the axis x. Specifically, for example, the inner peripheral end 22a extends on a cylindrical surface or a substantially cylindrical surface centered on the axis x. Also, the outer peripheral end 22b extends, for example, along a cylindrical surface centered on the axis x, and specifically, for example, the outer peripheral end 22b extends on a cylindrical surface or a substantially cylindrical surface centered on the axis x. Note that the outer peripheral end 22b is an outer peripheral side end of the base portion 22, and specifically, is an end surface facing the outer peripheral side of the base portion 22.

[0022] FIG. 8 is a partial enlarged front view showing a part of the conductive member 20 enlarged. As shown in FIGS. 4, 5, and 8, the plurality of conductive pieces 21 are arranged at intervals in the circumferential direction. As shown in FIG. 8, the conductive piece 21 has, for example, a rectangular or substantially rectangular plate-like shape, and has an inner circumferential end 21a which is the inner circumferential side end, side ends 21b and 21c which are a pair of circumferential ends, and an outer circumferential end 21d which is the outer circumferential side end. Specifically, the inner circumferential end 21a is an end face facing the inner circumferential side, and the side ends 21b and 21c are specifically end faces facing the circumferential direction. The side face 21b and the side face 21c face away from each other in the circumferential direction. Further, 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 circumferential end 21d of the conductive piece 21 and the inner circumferential end 22a of the base 22 are located at a position separated by a distance R1 which is a predetermined distance in the radial direction from the axis x.

[0023] The inner circumferential end 21a of the conductive piece 21 extends, for example, along a plane orthogonal to the radial direction. Specifically, the inner circumferential end 21a of the conductive piece 21 extends, for example, on a plane or a substantially plane orthogonal to the radial direction. The inner circumferential end 21a is located at a position separated by a distance R2 which is a predetermined distance in the radial direction from the axis x. The side faces 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, on a plane or a substantially plane including the axis x. The width W1 which is the circumferential width of the conductive piece 21 has a predetermined size. Note that the width W1 of the conductive piece 21 is the distance between the side face 21b and the side face 21c. Also, the length L1 which is the length of the conductive piece 21 has a predetermined length. Note that the length L1 of the conductive piece 21 is the length in the radial direction and is the distance in the radial direction between the inner circumferential end 21a and the outer circumferential end 21d.

[0024] As described above, the plurality of conductive pieces 21 are arranged side by side in the circumferential direction. As shown in FIGS. 4, 5, and 8, a gap 23 is formed between two adjacent conductive pieces 21 in the circumferential direction. The gap 23 extends to the inner circumferential end 22a of the base portion 22. That is, between two adjacent conductive pieces 21 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 with the gap 23 therebetween. The width W2 in the circumferential direction of the gap 23 is of 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.

[0025] As an example, as shown in FIG. 8, the side ends 21b and 21c of the conductive piece 21 each extend on a plane including the axis x, and the width W1 of the conductive piece 21 widens from the inner circumferential end 21a toward the outer circumferential end 21d in the radial direction. Also, in this case, the width W2 of the gap 23 is constant in the radial direction. Note that this form of the conductive piece 21 is an example, and the width W1 of the conductive piece 21 does not have to widen from the inner circumferential end 21a toward the outer circumferential end 21d in the radial direction, and the width W2 of the gap 23 does not have to be constant in the radial direction. For example, the conductive piece 21 may have a form in which the width W1 of the conductive piece 21 is of a constant width in the radial direction. Correspondingly, the width W2 of the gap 23 may narrow from the inner circumferential side toward the outer circumferential side in the radial direction. Also, for example, the conductive piece 21 may have a form in which it narrows from the inner circumferential end 21a toward the outer circumferential end 21d in the radial direction. Correspondingly, the width W2 of the gap 23 may widen from the inner circumferential side toward the outer circumferential side in the radial direction.

[0026] The widths W1 of the plurality of conductive pieces 21 are the same or substantially the same, respectively, and the widths W2 of the plurality of gaps 23 are the same or substantially the same, respectively. Therefore, in the conductive member 20, the plurality of conductive pieces 21 are arranged at equal angular intervals or substantially equal angular intervals around the axis x, and the plurality of gaps 23 are arranged at equal angular intervals or substantially equal angular intervals around the axis x. Note that the widths W1 of the plurality of conductive pieces 21 do not have to be the same as each other, and the widths W2 of the plurality of gaps 23 do not have to be the same as each other. Also, in the conductive member 20, the plurality of conductive pieces 21 do not have to be arranged at equal angular intervals around the axis x, and the plurality of gaps 23 do not have to be arranged at equal angular intervals around the axis x.

[0027] Also, as shown in FIGS. 4 and 5, the inner peripheral ends 21a of the plurality of conductive pieces 21 are arranged, for example, along a circle centered on the axis x when viewed in the direction of the axis x. Specifically, for example, the inner peripheral ends 21a of the plurality of conductive pieces 21 are located on a circle or a substantially circular shape centered on the axis x when viewed in the direction of the axis x, and the distances R2 from the axis x to the inner peripheral ends 21a of the plurality of conductive pieces 21 are the same or substantially the same as each other. That is, the inner peripheral ends 21a of the plurality of conductive pieces 21 are located on a circle with a radius R2 centered on the axis x or a substantially circular shape with a radius R2 when viewed in the direction of the axis x. The inner peripheral ends 21a of the plurality of conductive pieces 21 form the inner peripheral side end of the conductive member 20, and define a space (through hole) 20b that is circular or substantially circular in the direction of the axis x and penetrates the conductive member 20 in the direction of the axis x.

[0028] A shaft for forming a conductive path 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 plurality of conductive pieces 21 comes into contact with the outer peripheral surface of the shaft. In this way, each conductive piece 21 is configured to have a tightening margin δ with respect to the shaft in the usage state. Specifically, the distance R2 from the axis x to the inner peripheral end 21a of each conductive piece 21 is larger than the radius R0 of the shaft by the tightening margin δ.

[0029] As shown in FIGS. 6 and 7, the contact side surface 24 of the conductive member 20 extends, for example, along a plane orthogonal to the axis x. Specifically, the contact side surface 24 extends, for example, on a plane or a substantially plane orthogonal to the axis x. Also, as shown in FIGS. 6 and 7, the pressed side surface 25 of the conductive member 20 extends, for example, along a plane orthogonal to the axis x. Specifically, the pressed side surface 25 extends, for example, on a plane or a substantially plane orthogonal to the axis x. The plurality of conductive pieces 21 and the base 22 each have a part of the contact side surface 23 and the pressed side surface 25, and the plurality of conductive pieces 21 and the base 22 are flush. The thickness T1, which is the thickness of the conductive member 20, has a predetermined size. The thickness T1 of the conductive member 20 is, for example, constant or substantially constant over the entire conductive member 20. Note that the thickness T1 of the conductive member 20 is the distance between the contact side surface 23 and the pressed side surface 25.

[0030] As described above, the conductive member 20 has a plurality of conductive pieces 21 arranged in the circumferential direction at the inner peripheral end portion 20a, and a gap 23 is formed between two adjacent conductive pieces 21. Thus, the inner peripheral end portion 20a of the conductive member 20 is divided into a plurality of parts along the circumferential direction. Thereby, in the usage state described later, even when the shaft is passed through the inside of the conductive member 20 and the conductive member 20 is deformed, the pressing force of the conductive member 20 itself against the shaft can be reduced. Note that the pressing force is the force for tightening the shaft 110. The magnitude of the pressing force of the conductive member 20 itself against the shaft corresponds to the number of the conductive pieces 21. For this reason, the number of the conductive pieces 21 is, for example, a number corresponding to the magnitude of the pressing force of the conductive member 20 itself against the shaft.

[0031] Also, the magnitude of the pressing force of the conductive member 20 itself against the shaft can be adjusted by adjusting the width W1, the length L1, and the thickness T2 of each conductive piece 21. For this reason, the width W1, the length L1, and the thickness T2 of each conductive piece 21 are set to values such that the magnitude of the pressing force of the conductive member 20 itself against the shaft becomes a predetermined magnitude, for example, in the usage state of the conductive ring 1.

[0032] The conductive member 20 has the configuration as described above and is integrally formed from a conductive material. That is, the plurality of conductive pieces 21 and the base portion 22 are part of the integrally formed conductive member 20, and the plurality of conductive pieces 21 and the base portion 22 are integrated. The conductive material forming the conductive member 20 is, for example, a material in which a conductive material is added to the base material forming the conductive member 20. Specifically, for example, it is conductive PTFE (polytetrafluoroethylene). Conductive PTFE is obtained by adding a conductive material to PTFE (polytetrafluoroethylene) as a 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, rubbers, or fibers such as non-woven fabrics, etc., and the material of the conductive member 20 may be a material in which a conductive material is added to these base materials. Examples of the conductive material added to the base material include conductive particles such as carbon and metal powder.

[0033] The spring member 30 is provided in the conductive ring 1 so as to be arranged side by side with the conductive member 20 in the axial direction of the axis x. Further, the spring pieces 31 of the spring member 30 are elastically deformed along the axis x and generate an elastic force in the direction toward the axis x. Note that the direction toward the axis x is not limited to the direction toward the inner peripheral side in the radial direction, and any direction having a component in the direction toward the inner peripheral side in the radial direction is acceptable. The spring member 30 is, for example, annular around the axis x. Specifically, the spring member 30 is an annular leaf spring, and in the usage state of the conductive ring 1 described later, when the plurality of spring pieces 31 are elastically deformed, the plurality of conductive pieces 21 of the conductive member 30 are pressed against the outer peripheral surface 110a (see FIG. 10) of the shaft 110, and the plurality of conductive pieces 21 can generate an elastic force such that they have a pressing force of a predetermined magnitude with respect to the shaft 110. In this way, the plurality of spring pieces 31 cooperate with the plurality of conductive pieces 21 so that the plurality of conductive pieces 21 generate a pressing force of a predetermined magnitude with respect to the shaft 110.

[0034] The spring member 30 is, for example, an annular plate-like member around the axis x as shown in FIGS. 1 to 7, and has a pair of annular surfaces, a pressing side surface 34 and a back surface 35, which face away from each other in the direction of the axis x as shown in FIGS. 3, 6, and 7. The pressing side surface 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 an inner peripheral end portion 30a which is an end portion on the inner peripheral side, and also has a base portion 32 which is an annular portion. The base portion 32 is a portion on the outer peripheral side of the spring piece 31 in the spring member 30 as shown in FIGS. 3, 6, and 7. A plurality of spring pieces 31 extend from an inner peripheral end 32a which is an end on the inner peripheral side of the base portion 32 toward the inner peripheral side. The base portion 32 is, for example, an annular plate-like portion around the axis x as shown in FIGS. 3, 6, and 7, and the inner peripheral end 32a extends along, for example, a cylindrical surface having the axis x as a central axis. Specifically, for example, the inner peripheral end 32a extends on a cylindrical surface or a substantially cylindrical surface having the axis x as a central axis. Further, the outer peripheral end 32b extends along, for example, a cylindrical surface having the axis x as a central axis. Specifically, for example, the outer peripheral end 32b extends on a cylindrical surface or a substantially cylindrical surface having the axis x as a central axis. Note that the outer peripheral end 32b is an end on the outer peripheral side of the base portion 32, and specifically, is an end surface facing the outer peripheral side of the base portion 32.

[0035] FIG. 9 is a partially enlarged front view showing a part of the spring member 20 enlarged. As shown in FIGS. 2, 5, and 9, the plurality of spring pieces 31 are arranged at intervals in the circumferential direction. As shown in FIG. 9, the spring piece 31 has, for example, a rectangular or substantially rectangular plate-like shape, and has an inner peripheral end 31a which is an end on the inner peripheral side, a pair of circumferential ends 31b and 31c, and an outer peripheral end 31d which is an end on the outer peripheral side. Specifically, the inner peripheral end 31a is an end surface facing the inner peripheral side, and the circumferential ends 31b and 31c are end surfaces facing the circumferential direction. The circumferential end 31b and the circumferential end 31c face away from each other in the circumferential direction. Further, the outer peripheral end 31d is specifically a boundary between the spring piece 31 and the base portion 32, and the spring piece 31 is connected to the inner peripheral end 32a of the base portion 32 at the outer peripheral 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 position separated by a distance R3 which is a predetermined distance in the radial direction from the axis x.

[0036] The inner peripheral end 31a of the spring piece 31 extends, for example, along a plane orthogonal to the radial direction, and the inner peripheral end 31a is located at a position separated from the axis x by a distance R4 which is a predetermined distance in the radial direction. The side ends 31b, 31c of the spring piece 31 extend, for example, along the radial direction. Specifically, for example, the side ends 31b, 31c of the spring piece 31 extend on a plane or a substantially plane including the axis x. The width W3 which is the circumferential width of the spring piece 31 has a predetermined size. Note that the width W3 of the spring piece 31 is the distance between the side surface 31b and the side surface 31c. The width W3 of the spring piece 31 is equal to or less than the width W1 of the conductive piece 21 (W3≦W1). As an example, as shown in FIG. 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 width W1 of the conductive piece 21 in the whole conductive piece 21. Further, as shown in FIG. 9, the length L2 which is the length of the spring piece 31 has a predetermined length. Note that the length L2 of the spring piece 31 is the distance in the radial direction between the inner peripheral end 31a and the outer peripheral end 31d. Also, the thickness T2 which is the thickness of the spring piece 31 (see FIG. 3) has a predetermined size. The thickness T2 of the spring piece is, for example, constant or substantially constant over the whole spring piece 31. Note that the thickness T2 of the spring piece 31 is the distance between the pressing side surface 34 and the back surface 35 in the spring piece 31.

[0037] As described above, the spring piece 31 is adapted to elastically deform along the axis x. Specifically, as will be described later, in the use state of the conductive ring 1, the deformed conductive piece 21 is pressed toward the axis x. The width W3, the length L2, and the thickness T2 of the spring piece 31 are set, for example, to values such that the deformed conductive piece 21 is pressed toward the axis x with a predetermined force in the use state of the conductive ring 1.

[0038] As described above, the plurality of spring pieces 31 are arranged side by side in the circumferential direction. As shown in FIGS. 5 and 9, a space 33 is formed between two spring pieces 31 adjacent to each other in the circumferential direction. The space 33 is a space defined by a side end 31b of one spring piece 31, a side end 31c of the other spring piece 31, and an inner circumferential end 32a of a base portion 32 extending between the two spring pieces 31, between the two spring pieces 31 adjacent to each other in the circumferential direction. As shown in FIG. 9, the width W4 in the circumferential direction of the space 33 has a predetermined size. Note that 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.

[0039] The widths W3 of the plurality of spring pieces 31 are the same or substantially the same, respectively, and the widths W4 of the plurality of spaces 33 are the same or substantially the same, respectively. Therefore, in the spring member 30, the plurality of spring pieces 31 are arranged at equal angular intervals or substantially equal angular intervals around the axis x, and the plurality of spaces 33 are arranged at equal angular intervals or substantially equal angular intervals around the axis x. Note that the widths W3 of the plurality of spring pieces 31 do not have to be the same as each other, and the widths W4 of the plurality of spaces 33 do not have to be the same as each other. Also, in the spring member 30, the plurality of spring pieces 31 do not have to be arranged at equal angular intervals around the axis x, and the plurality of spaces 33 do not have to be arranged at equal angular intervals around the axis x.

[0040] Also, as shown in FIG. 7, in the conductive ring 1, the outer circumferential ends 31d of the plurality of spring pieces 31 are positioned on the outer circumferential side of the outer circumferential ends 21d of the plurality of conductive end pieces 21. That is, the radius R3 of the inner circumferential end 32a of the base portion 32 of the spring member 30 is larger than the radius R1 of the inner circumferential end 22a of the base portion 22 of the conductive member 20.

[0041] As shown in FIG. 5, the inner peripheral ends 31a of the plurality of spring pieces 31 are arranged along a circle centered on the axis x, for example, when viewed in the direction of the axis x. Specifically, for example, the inner peripheral ends 31a of the plurality of spring pieces 31 are located on a circle or a substantially circular shape centered on the axis x, and the distances R4 from the axis x of the respective inner peripheral ends 31a of the plurality of spring pieces 31 are the same or substantially the same as each other. That is, the inner peripheral ends 31a of the plurality of spring pieces 31 are located on a circle with a radius R4 centered on the axis x or a substantially circular shape with a radius R4 when viewed in the direction of the axis x.

[0042] As shown in FIGS. 6 and 7, the pressing side surface 34 of the spring member 30 is along a plane orthogonal to the axis x, for example. Specifically, for example, the pressing side surface 34 extends on a plane or a substantially plane orthogonal to the axis x. Also, as shown in FIGS. 6 and 7, the back surface 35 of the spring member 30 is along a plane orthogonal to the axis x, for example. Specifically, for example, the back surface 35 extends on a plane or a substantially plane orthogonal to the axis x. The plurality of spring pieces 31 and the base 32 each have a part of the pressing side surface 34 and the back surface 35, and the plurality of spring pieces 31 and the base 32 are flush-connected.

[0043] As shown in FIGS. 6 and 7, the spring member 30 has a shape that overlaps the conductive member 20 in the direction of the axis x. For example, the base 32 of the spring member 30 has the same or substantially the same shape and size as the portion from the outer peripheral end 22b to the vicinity of the inner peripheral end 22a of the base 22 of the conductive member 20, and 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 with each other or substantially coincide with each other, respectively, so that the spring member 30 and the conductive member 20 overlap each other.

[0044] Also, as shown in FIGS. 5 to 7, in the conductive member 1, the plurality of spring pieces 31 are each configured to contact the plurality of conductive pieces 21. Specifically, the number of the plurality of spring pieces 31 is equal to the number of the plurality of conductive pieces 21, and one of the plurality of spring pieces 31 corresponds to one of the plurality of conductive pieces 21. Each spring piece 31 is configured to contact the corresponding conductive piece 21. Specifically, the pressing side surface 34 of each spring piece 31 contacts the pressed side surface 25 of the corresponding conductive piece 21. The distance R4 from the axis x of the inner peripheral 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 contacts the corresponding conductive piece 21.

[0045] As described above, in the conductive ring 1, the outer peripheral end 31d of the spring piece 31 is located on the outer peripheral side of 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 portion 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 at a position on the outer peripheral end 22d side of the radial center of the conductive piece 21. Note that 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 radial center of the conductive piece 21, or 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 peripheral end 31a of the spring piece 31 is larger than the radius R2 of the inner peripheral end 21a of the conductive piece 21, and is smaller than the radius R1 of the outer peripheral end 21d of the conductive piece 21. Note that the radius R4 of the inner peripheral end 31a of the spring piece 31 may be the same as the radius R2 of the inner peripheral end 21a of the conductive piece 21, or may be smaller than the radius R2 of the inner peripheral end 21a of the conductive piece 21. For example, in the usage state of the conductive ring 1 described later, within a range where the spring piece 31 does not contact the shaft, the radius R4 of the inner peripheral end 31a of the spring piece 31 may be smaller than the radius R2 of the inner peripheral end 21a of the conductive piece 21.

[0046] Further, as shown in FIG. 5, the spring piece 31 is configured to contact, for example, the center or substantially the center in the circumferential direction of the conductive piece 21. Also, 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.

[0047] The spring member 30 has the above-described configuration, and the inner peripheral end portion 30a has a comb-like shape formed 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 portion 32 are part of the integrally formed spring member 31, and the plurality of spring pieces 31 and the base portion 32 are integrated. The elastic material forming the spring member 30 is, for example, metal. The metal forming the spring member 30 is, for example, stainless steel. Note that the elastic material forming the spring member 30 is not limited to metal, and may be, for example, a polymer material.

[0048] As shown in FIGS. 1 to 7, specifically, the holding member 10 has an inner holding member 11 located inside and an outer holding member 15 located outside. The inner holding member 11 and the outer holding member 15 are annular members around the axis x, and are configured such that the conductive member 20 and the spring member 30 can be stacked and held between them.

[0049] As shown in FIGS. 1, 3, 4, 6, and 7, the inner holding member 11 has, for example, a fitting portion 12 that is an annular portion around the axis x and a holding portion 13 that is an annular portion around the axis x. The fitting portion 12 is a cylindrical portion extending along the axis x, and the holding portion 13 is an annular portion extending from the front end of the fitting portion 12 to the inner peripheral side. The fitting portion 12 is, for example, cylindrical or substantially cylindrical with the axis x as the central axis or substantially the central axis.

[0050] As shown in FIGS. 2, 3, 5 to 7, the outer holding member 15 has, for example, a fitting portion 16 that is an annular portion around the axis x and a holding portion 17 that is an annular portion around the axis x. The fitting portion 16 is a cylindrical portion extending along the axis x, and the holding portion 17 is an annular portion extending from the front end of the fitting portion 16 to the inner peripheral side. The fitting portion 16 is, for example, cylindrical or substantially cylindrical with the axis x as the central axis or substantially central axis.

[0051] As shown in FIGS. 6 and 7, the inner holding member 11 and the outer holding member 15 are configured to be combined with each other. Specifically, for example, the diameter of the outer peripheral surface 12a of the fitting portion 12 of the inner holding member 11 is smaller than the diameter of the inner peripheral surface 16a of the fitting portion 16 of the outer holding member 15, and the fitting portion 12 of the inner holding member 11 is inserted into the inner peripheral side of the fitting portion 16 of the outer holding member 15, so that the fitting portion 12 of the inner holding member 11 and the fitting portion 16 of the outer holding member 15 are fitted to each other in a clearance fit state. The outer peripheral surface 12a of the fitting portion 12 is an annular surface facing the outer peripheral side of the fitting portion 12, and the inner peripheral surface 16a of the fitting portion 16 is an annular surface facing the inner peripheral side of the fitting portion 16. Also, as shown in FIGS. 6 and 7, in a state where the fitting portion 12 of the inner holding member 11 and the fitting portion 16 of 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 configured to have portions facing each other in the axis x direction. Note that the diameter of the outer peripheral surface 12a of the fitting portion 12 of the inner holding member 11 may be larger than the diameter of the inner peripheral surface 16a of the fitting portion 16 of the outer holding member 15, and the fitting portion 12 and the fitting portion 16 may be fitted to each other in an interference fit state. Also, the diameter of the outer peripheral surface 12a of the fitting portion 12 and the diameter of the inner peripheral surface 16a of the fitting portion 16 may be the same as each other.

[0052] 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 21 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 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 to the inner peripheral surface 21a 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 of the spring member 30 from the position on the inner peripheral side of the outer peripheral end 31d of each of the plurality of spring pieces 31 to the inner peripheral end 31a 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).

[0053] 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 directed toward the axis x generated by the deformed conductive piece 21 in the use 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 use state of the conductive ring 1.

[0054] Also, the position in the radial direction of the inner peripheral end 13a of the holding portion 13 with respect to the spring piece 31, that is, the relationship between the distance R6 and the distance R4, is related to the magnitude of the pressing force directed toward the axis x generated by the deformed spring piece 31 in the usage state of the conductive ring 1. Therefore, the distance R6 of the inner peripheral end 13a of the holding portion 13 is set to a value such that, for example, in the usage state of the conductive ring 1, the pressing force generated by the deformed spring piece 31 becomes a predetermined magnitude.

[0055] In addition, the inner peripheral end 17a of the holding portion 17 may be located at the same position in the radial direction as the inner peripheral end 22a of the base portion 22 of the conductive member 20 (R5 = R1). Also, the inner peripheral end 17a of the holding portion 17 may be located on the outer peripheral side of the inner peripheral end 22a in the radial direction (R5 > R1). In this case, a part of the contact surface 21 of the base portion 22 of the conductive member 20 faces the holding portion 17. Similarly, the inner peripheral end 13a of the holding portion 13 may be located at the same position in the radial direction as the inner peripheral end 32a of the base portion 32 of the spring member 30 (R6 = R3). Also, the inner peripheral end 13a of the holding portion 13 may be located on the outer peripheral side of the inner peripheral end 32a in the radial direction (R6 > R3). In this case, a part of the back surface 35 of the base portion 32 of the spring member 30 faces the holding portion 13.

[0056] As shown in FIGS. 6 and 7, the inner holding member 11 and the outer holding member 15 are combined, and the conductive member 20 and the spring member 30 that are overlapped with each other are respectively sandwiched between the holding portion 13 of the inner holding member 11 and the holding portion 17 of the outer holding member 15 at the base portions 22 and 32 and are pressed in the direction of the axis x. A pressing portion 18 is formed on the fitting portion 16 of the outer holding member 15, and the inner holding member 11 is fixed to the outer holding member 15. The pressing portion 18 of the outer holding member 15 is a portion that contacts the fitting portion 12 of the inner holding member 11 and fixes the fitting portion 12 in the direction of the axis x with respect to the fitting portion 16. In this way, the conductive member 20 and the spring member 30 that are overlapped with each other are in a state of being fixed between the inner holding member 11 and the outer holding member 15 (hereinafter, also referred to as the "assembled state").

[0057] The inner holding member 11 and the outer holding member 15 are made of a conductive metal. Note that the inner holding member 11 and the outer holding member 15 may be formed of other conductive materials.

[0058] Each component of the conductive ring 1 has the above-described configuration, is assembled into an assembled state, and becomes the conductive ring 1 as shown in FIGS. 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 pushed toward the front side by the pressing portion 18 of the fitting portion 16 of the outer holding member 15. Further, the conductive member 20 and the spring member 30 that are overlapped with 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 overlapped with each other such that the pressed side surface 25 of the conductive member 20 contacts the pressing side surface 35 of the spring member 30. The conductive member 20 and the spring member 30 are respectively held by the inner holding member 11 and the outer holding member 15 at the base portions 22 and 32. In this way, the inner holding member 11 is fixed to the outer holding member 15, and the conductive member 20 and the spring member 30 are fixed between the inner holding member 11 and the outer holding member 15. Further, the conductive member 20 and the spring member 30 are respectively attached to the inner holding member 11 and the outer holding member 15 such that the contact side surface 21 of the conductive member 20 contacts the shaft in the use state described later. Note that, as shown in FIGS. 1 to 7, the conductive member 20 and the spring member 30 are respectively attached to the inner holding member 11 and the outer holding member 15 such that the contact side surface 21 of the conductive member 20 faces the front side, but the conductive member 20 and the spring member 30 may be respectively attached to the inner holding member 11 and the outer holding member 15 such that the contact side surface 21 of the conductive member 20 faces the back side.

[0059] Also, in the assembled conductive ring 1, as described above, each spring piece 31 contacts the corresponding conductive piece 21. Specifically, the pressing side surface 34 of each spring piece 31 contacts the pressed side surface 25 of the corresponding conductive piece 21. Each spring piece 31 extends from near the inner peripheral end 22a of the base portion 22 of the conductive member 20 beyond the inner peripheral end 22a to the corresponding conductive piece 21. As an example, as shown in FIGS. 1 to 7, the spring piece 31 extends to the vicinity of the center on the outer peripheral end 22d side rather than 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 rather than the radial center of the conductive piece 21 and in the vicinity of this center. Also, the spring piece 31 is located at the center or substantially the center in the circumferential direction of the conductive piece 21 and contacts the center or substantially the center in the circumferential direction of the conductive piece 21.

[0060] Before reaching the assembled state as shown in FIGS. 1, 2, 4 to 7, the fitting portion 16 of the outer holding member 15 may not have the pressing portion 18. For example, the conductive member 20 and the spring member 30 that are overlapped with each other are attached to the outer holding member 15 in which the pressing portion 18 is not formed on the fitting portion 16, and then, after attaching the fitting portion 12 of the inner holding member 11 to the fitting portion 16 of the outer holding member 15, the pressing portion 18 may be formed on the fitting portion 16. That is, by forming the pressing portion 18, the fitting portion 12 and the fitting portion 16 are caulked, and the end of the fitting portion 12 is pressed to the front side by the pressing portion 18, so that the conductive member 20, the spring member 30, the inner holding member 11, and the outer holding member 15 may be brought into the assembled state as shown in FIGS. 1 to 7.

[0061] Incidentally, as shown in Fig. 7, the clamping margin δ of the conductive piece 21 is the radial width of the conductive piece 21 of the conductive member 20 of the conductive ring 1 in the assembled state, that is, in the free state where no external force is applied to the conductive member 20 and the spring member 30, from the inner peripheral end 21a to the position separated from the axis x by a distance of the radius R0 of the shaft 110 in the radial direction. When the conductive piece 21 sags due to use in the usage state described later, the conductive piece 21 is plastically deformed, and in the free state where no external force is applied to the conductive member 20 and the spring member 30, the conductive piece 21 has a curved shape such that the inner peripheral end 21a is displaced in the direction of the axis x, and the position of the inner peripheral end 21a of the conductive piece 21 is displaced to the outer peripheral side in the radial direction. Therefore, when the conductive piece 21 sags and deforms, the clamping margin δ of the conductive piece 21 decreases.

[0062] Next, the operation of the conductive ring 1 will be described. FIG. 10 is a conceptual diagram for showing an example of an application target of the conductive ring 1. FIG. 11 is a cross-sectional view showing an example of the usage state of the conductive ring 1 in the application target shown in FIG. 10. As an example, the conductive ring 1 is applied to a drive device 100 of a battery electric vehicle (BEV) as shown in FIG. 10. The drive device 100 has, for example, as shown in FIG. 10, an electric motor 101, a speed reducer 102, an inverter 103 for controlling the electric motor 101, and a battery 104 as a power source. In the electric motor 101, a shaft 110 is rotatably supported by a bearing 112 supported in a housing 111, and also extends out of the housing 111 through a shaft hole 113 of the housing 111. The shaft 110 of the electric motor 101 enters the housing 120 of the speed reducer 102 through a shaft hole 124 of the housing 120 of the speed reducer 102, and is rotatably supported by a bearing 123 supported in the housing 120. Further, the shaft 110 is connected to a reduction gear stage 121 in the housing 120. The speed reducer 102 is provided with a shaft 122 that outputs a rotational driving force reduced by the reduction gear stage 121. The shaft 122 is rotatably supported by a bearing 123 supported in the housing 120, and is also connected to a wheel 105 so as to be able to transmit a rotational driving force to the wheel 105. An oil seal 125 for sealing a gap between the shaft hole 124 and the shaft 110 of the electric motor 101 is attached to the shaft hole 124 of the housing 120 of the speed reducer 102. An oil seal 127 for sealing a gap between the shaft hole 126 and the shaft 122 is attached to a shaft hole 126 of the housing 120 through which the shaft 122 of the speed reducer 102 passes. Note that the shaft 110 and the housing 111 of the electric motor 101 are made of metal, and the housing 120 and the shaft 122 of the speed reducer 102 are made of metal.

[0063] The conductive ring 1 is provided, as an example, between the housing 111 and the shaft 110 of the electric motor 101 and comes into a use state. Specifically, as shown in FIG. 11, 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, the conductive ring 1 is fixed to the shaft hole 113, and the shaft 110 is inserted into the conductive member 20, whereby the conductive ring 1 comes into a use state. In the use state, the contact side surfaces 24 of the plurality of conductive pieces 21 of the conductive member 20 are in contact with the outer peripheral surface 110a of the shaft 110, and the plurality of conductive pieces 21 of the conductive member 20 are pushed to the outer peripheral side of the shaft 110 and deformed. As shown in FIG. 11, the plurality of conductive pieces 21 of the conductive member 20 have a width in the axial line x direction corresponding to the interference δ of the conductive piece 21 and are in contact with the outer peripheral surface 110a of the shaft 110. Further, the holding member 10 (the inner holding member 11 and the outer holding member 15) to which the conductive member 20 is attached is made of a conductive metal and is in contact with the inner peripheral surface 113a of the shaft hole 113 of the housing 111. Thus, the conductive member 20 and the holding member 10 form an electric conduction path for flowing electricity between the shaft 110 and the housing 111 of the electric motor 101 in the use state.

[0064] As described above, in the use state, the plurality of conductive pieces 21 of the conductive member 20 are pushed to the outer peripheral side of the shaft 110 and deformed. Therefore, a reaction force for pressing the shaft 110 is generated in each of the plurality of conductive pieces 21, and the plurality of conductive pieces 21 generate a tightening force for clamping the shaft 110.

[0065] Also, as shown in FIG. 10, each of the plurality of spring pieces 31 of the spring member 30 overlaps the plurality of 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 use state, the plurality of conductive pieces 21 are deformed by receiving a reaction force from the outer peripheral side of the shaft 110, and each of the plurality of spring pieces 31 is also deformed by receiving a force from the shaft 110 toward the outer peripheral side through the corresponding conductive piece 21. Since the plurality of spring pieces 31 have elasticity as described above, the plurality of 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 the reaction force of each spring piece 31, each conductive piece 21 is pressed against the outer peripheral surface 110a of the shaft 110 and is pressed toward the shaft 110. In this way, the plurality of spring pieces 31 clamp the shaft 110 via the plurality of conductive pieces 21, and the plurality of spring pieces 31 generate a clamping force for clamping the shaft 110.

[0066] In this way, in the use state, the plurality of conductive pieces 21 generate a clamping force, and the plurality of spring pieces 31 also generate a clamping force. Therefore, the plurality of conductive pieces 21 clamp the shaft 110 by the clamping force generated by the plurality of spring pieces 31 in addition to the clamping force generated by themselves. In this way, each of the plurality of conductive pieces 21, in cooperation with the contacting spring piece 31, generates a clamping force against the shaft 110. As a result, the contact between the plurality of conductive pieces 21 and the shaft 110 becomes strong. Also, the followability of the plurality of conductive pieces 21 with respect to the shaft 110 is improved, and in this respect as well, the contact between the plurality of conductive pieces 21 and the shaft 110 becomes strong. For this reason, in the conductive structure 1, the contact between the conductive member 20 and the shaft 110 is stable. As a result, it is possible to maintain the impedance of the conductive path formed by the conductive ring 1 between the shaft 110 of the electric motor 101 and the housing 111 over time or suppress a change in impedance, and the conductive path between the shaft 110 of the electric motor 101 and the housing 111 can be made into a conductive path through which electricity flows stably.

[0067] Further, the conductive member 20 is made of PTFE resin and is prone to sagging over time. For this reason, when the conductive ring 1 is placed in the use state for a desired usage time, the plurality of conductive pieces 21 plastically deform, and the pressing force generated by the reaction force of the plurality of conductive pieces 21 decreases. Depending on the length of the usage time, the reaction force generated in the plurality of conductive pieces 21 may become small or no reaction force may be generated in the plurality of conductive pieces 21. In this case, the pressing force of the plurality of conductive pieces 21 themselves against the shaft 110 becomes small or the plurality of conductive pieces 21 themselves do not generate a pressing force against the shaft 110.

[0068] On the other hand, the conductive ring 1 has a spring member 30 having a plurality of spring pieces 31 corresponding to each of the plurality of conductive pieces 21. In the use state, each spring piece 31 presses the corresponding conductive piece 21 against the shaft 110, and the plurality of conductive pieces 21 clamp the shaft 110 by the pressing force generated by the plurality of spring pieces 31. For this reason, in the use state, even if the pressing force of the plurality of conductive pieces 21 themselves against the shaft 110 decreases over time or the pressing force of the plurality of conductive pieces 21 themselves against the shaft 110 disappears, the plurality of conductive pieces 21 can continue to clamp the shaft 110 by the pressing force generated by the plurality of spring pieces 31, and the pressing force of the plurality of conductive pieces 21 against the shaft 110 can be maintained or a decrease in the pressing force can be suppressed. Therefore, the impedance of the conductive path formed by the conductive ring 1 over time can be maintained or a change in the impedance can be suppressed, and the conductive path formed by the conductive ring 1 can be made into a conductive path through which electricity flows stably.

[0069] Also, the inner peripheral end portion 20a of the conductive member 20 is formed of a plurality of conductive pieces 21 arranged apart from each other in the circumferential direction. For this reason, in the use state, the plurality of conductive pieces 21 come into contact with the shaft 110, and each of the plurality of conductive pieces 21 deforms. In this way, the circumferential restraint force of each conductive piece 21 is reduced, and the magnitude of the pressing force generated by the plurality of conductive pieces 21 themselves can be made small. Thereby, wear of the plurality of conductive pieces 21 caused by the rotation of the shaft 110 can be suppressed.

[0070] Further, the conductive ring 1 may be provided between the housing 120 and the shaft 122 of the speed reducer 102. Specifically, as shown in FIG. 10, the conductive ring 1 may be provided in the gap between the shaft hole 126 of the housing 120 and the shaft 122 outside the oil seal 127. Also in this case, similar to the conductive ring 1 attached to the electric motor 101, the conductive member 20 and the holding member 10 of the conductive ring 1 form a conductive path for flowing electricity between the shaft 122 and the housing 120 of the speed reducer 102. Note that the conductive ring 1 may be used in oil and may be provided inside the oil seal 127.

[0071] Note that the above-described drive device 100 is an example of the application target of the conductive ring 1, and the application target of the conductive ring 1 is not limited to this. The conductive ring 1 is used, for example, in drive devices of electric vehicles (EVs) such as hybrid vehicles (HV), fuel cell vehicles (FCV), etc., in addition to battery electric vehicles (BEV). In vehicles equipped with an electric motor such as an electric vehicle (EV), the shafts 110 and 120 may be charged due to an induced current or the like generated from the motor, and electromagnetic wave noise may be generated. Also, due to the on / off operation of an inverter for controlling the current supplied to an electric motor such as an electric motor, or the induced voltage or the like of the electric motor itself, the shafts 110 and 120 may be charged and electromagnetic wave noise may be generated. As described above, the conductive ring 1 forms a conductive path and flows the voltage charged on the shafts 110 and 122 to the housings 111 and 120. Thereby, it is possible to prevent communication failures and malfunctions from occurring in electronic devices, and electrolytic corrosion from occurring in metal parts such as bearings.

[0072] As described above, the conductive ring 1 according to the embodiment of the present invention can suppress a decrease in the pressing force on the shaft 110.

[0073] Next, a modified example of the conductive member 20 will be described. FIG. 12 is a front view of a conductive member 20A as an example of a modified example of the conductive member 20. Hereinafter, for the configuration of the conductive member 20A, the same components or components having the same functions as those of the above-described conductive member 20 are denoted by the same reference numerals and their description is omitted, and the configuration different from that of the conductive member 20 will be described.

[0074] As shown in FIG. 12, the conductive member 20A has at least one gap 27 provided so as to extend in the radial direction and at least one conductive member piece 26 extending around an axis x. The conductive member piece 26 has a pair of ends 28a and 28b in the direction around the axis x. The gap 26 is continuous with the ends 28a and 28b of the conductive member piece 26.

[0075] As shown in FIG. 12, the conductive member 20A is, for example, an annular plate-like structure composed of two gaps 27 (gaps 27A and 27B) and two conductive member pieces 26 (conductive member pieces 26A and 26B). As shown in FIG. 12, the conductive member piece 26A has a pair of ends 28Aa and 28Ab as a pair of ends 28a and 28b, and the conductive member piece 26B has a pair of ends 28Ba and 28Bb as a pair of ends 28a and 28b. One of the pair of ends (end 28Aa) of one of the conductive member pieces 26 (conductive member piece 26A) and one of the pair of ends (28Ba) of the other of the conductive member pieces 26 (conductive member piece 26B) face each other in the direction around the axis x (circumferential direction). Also, the other of the pair of ends (end 28Ab) of the conductive member piece 26A and the other of the pair of ends (end 28Bb) of the conductive member piece 26B face each other in the direction around the axis x (circumferential direction). One of the gaps 27 (gap 27A) is formed between the end 28Aa of the conductive member piece 26A and the end 28Ba of the conductive member piece 26B, and the other of the gaps 27 (gap 27B) is formed between the end 28Ab of the conductive member piece 26A and the end 28Bb of the conductive member piece 26B.

[0076] The conductive member pieces 26A and 26B are members corresponding to a part of the conductive member 20 of the conductive ring 1 shown in FIGS. 1 to 8, and coincide 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 shown in FIGS. 1 to 8 so as to form gaps 27A and 27B. For this reason, the shape of the cross section by the plane including the axis x of the conductive member pieces 26A and 26B is the same as the cross-sectional shape of the conductive member 20 shown in FIG. 12. The conductive member piece 26A and the conductive member piece 26B are, for example, the same. Note that the conductive member piece 26A and the conductive member piece 26B do not have to be the same. The conductive member pieces 26A and 26B extend, for example, along an arc or a substantially arc centered on the axis x as shown in FIG. 12. Specifically, for example, as shown in FIG. 12, the conductive member pieces 26A and 26B extend in the circumferential direction so as to be shorter than a semi-circle of the circle along which the conductive member pieces 26A and 26B extend.

[0077] In the conductive ring 1, the conductive member 20A is provided in the same manner as the conductive member 20. That is, the conductive member piece 26A is overlapped with the spring member 30 in the same manner as a part of the corresponding conductive member 20 of the conductive member piece 26A. A plurality of corresponding spring pieces 31 of the spring member 30 contact a plurality of conductive pieces 21 of the conductive member piece 26A. Similarly, a plurality of corresponding spring pieces 31 of the spring member 30 contact a plurality of conductive pieces 21 of the conductive member piece 26B. Further, two gaps 27A and 27B are interposed between the conductive member piece 26A and the conductive member piece 26B overlapped with the spring member 30. Specifically, a 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 a 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 continuous with the end 28Aa of the conductive member piece 26A and the end 28Ba of the conductive member piece 26B, and the gap 27B is continuous with the end 28Ab of the conductive member piece 26A and the end 28Bb of the conductive member piece 26B.

[0078] The conductive ring 1 having the conductive member 20A according to the modified example is also used in the same manner as the above-described conductive ring 1 to form a conductive path between the shaft 110 and the housing 111 of the electric motor 101. Further, the conductive member 20A according to the modified example also acts in the same manner as the above-described conductive ring 1 and exhibits the same effects.

[0079] Also, in the conductive ring 1 having the conductive member 20A according to the modified example, the conductive member pieces 26A and 26B are arranged annularly with gaps 27A and 27B therebetween. For this reason, even if an external force is applied to the conductive member pieces 26A and 26B due to the rotation of the shaft 110 in the use state, the conductive member pieces 26A and 26B can escape into the gaps 27A and 27B. Therefore, it is possible to suppress the occurrence of deformation such as stress concentration and contact with the shaft 110 in the conductive member pieces 26A and 26B. Thereby, wear of the conductive member pieces 26A and 26B and sagging of the conductive member pieces 26A and 26B can be suppressed.

[0080] Also, 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. Thereby, it is possible to suppress the occurrence of deformation such as wrinkles in the conductive member pieces 26A and 26B when fixing the conductive member pieces 26A and 26B to the holding member 10.

[0081] Next, another modification example of the conductive member 20 will be described. FIG. 13 is a front view of a conductive member 20B as another example of a modification example of the conductive member 20. As shown in FIG. 10, the conductive member 20B according to another modification example has one conductive member piece 26C as the conductive member piece 26 and one gap 27C as the gap 27. In the conductive member 20B, one of the gaps 27A or 27B is absent, and the conductive member piece 26A or 26B extends also to a part of one of the gaps 27A or 27B, and the conductive member piece 26A and the conductive member piece 26B are connected at a part of one of the gaps 27A or 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 a substantially circular shape centered or substantially centered on the axis x as shown in FIG. 13, and the end 28Ca and the end 28Cb are opposed in the circumferential direction, specifically, for example, opposed in the direction orthogonal to the axis x. The conductive member piece 26C has a conductive member piece 20C which is a member corresponding to a part of the conductive member 20, similarly to the conductive member pieces 26A and 26B. Note that the conductive member 20 may have three or more gaps 27 and three or more conductive member pieces 26. Also in this case, the plurality of gaps 27 and the plurality of conductive member pieces 26 are connected in an annular shape.

[0082] Next, a modification example of the spring member 30 will be described. The spring member 30 may be modified in the same manner as the above-described conductive member 20. FIG. 14 is a front view of a spring member 30A as an example of a modification example of the spring member 30. Hereinafter, for the configuration of the spring member 30A, the same components or components having the same functions as those of the above-described spring member 30 will be denoted by the same reference numerals and their description will be omitted, and the configuration different from that of the spring member 30 will be described.

[0083] As shown in FIG. 14, the spring member 30A has at least one gap 37 provided so as to extend in the radial direction and at least one spring member piece 36 extending around the axis x. The spring member piece 36 has a pair of ends 38a and 38b in the direction around the axis x. The gap 36 is continuous with the ends 38a and 38b of the spring member piece 36.

[0084] As shown in FIG. 14, the spring member 30A is, for example, an annular plate-like structure composed of two gaps 37 (gaps 37A and 37B) and two spring member pieces 36 (spring member pieces 36A and 36B). As shown in FIG. 14, the spring member piece 36A has a pair of ends 38Aa and 38Ab as a pair of ends 38a and 38b, and the spring member piece 36B has a pair of ends 38Ba and 38Bb as a pair of ends 38a and 38b. One of the pair of ends (end 38Aa) of one of the spring member pieces 36 (spring member piece 36A) and one of the pair of ends (38Ba) of the other of the spring member pieces 36 (spring member piece 36B) face each other in the direction around the axis x (circumferential direction). Also, the other of the pair of ends (end 38Ab) of the spring member piece 36A and the other of the pair of ends (end 38Bb) of the spring member piece 36B face each other in the direction around the axis x (circumferential direction). One of the gaps 37 (gap 37A) is formed between the end 38Aa of the spring member piece 36A and the end 38Ba of the spring member piece 36B, and the other of the gaps 37 (gap 37B) is formed between the end 38Ab of the spring member piece 36A and the end 38Bb of the spring member piece 36B. For example, the spring member pieces 36A and 36B extend around the axis x with the same or substantially the same length as the conductive member pieces 26A and 26B. That is, the spring member piece 36A and the conductive member piece 26A can be overlapped with each other by making the end 38Aa and the end 28Aa, and the end 38Ab and the end 28Ab coincide or substantially coincide with each other when viewed in the axis x direction. Similarly, the spring member piece 36B and the conductive member piece 26B can be overlapped with each other by making the end 38Ba and the end 28Ba, and the end 38Bb and the end 28Bb coincide or substantially coincide with each other when viewed in the axis x direction.

[0085] The spring member pieces 36A and 36B correspond to a part of the spring member 30 of the conductive ring 1 shown in FIGS. 1 to 7 and 9, and coincide or substantially coincide with a part of the spring member 30. The spring member pieces 36A and 36B are formed, for example, by dividing the spring member 30 shown in FIGS. 1 to 7 and 9 so as to form gaps 37A and 37B. For this reason, the shape of the cross section by the plane including the axis x of the spring member pieces 36A and 36B is the same as the cross-sectional shape of the spring member 40 shown in FIG. 14. The spring member piece 36A and the spring member piece 36B are, for example, the same. Note that the spring member piece 36A and the spring member piece 36B do not have to be the same. The spring member pieces 36A and 36B extend, for example, along an arc or a substantially arc centered on the axis x as shown in FIG. 14. Specifically, for example, as shown in FIG. 14, the spring member pieces 36A and 36B extend in the circumferential direction so as to be shorter than a semi-circle of the circle along which the spring member pieces 36A and 36B extend.

[0086] In the conductive ring 1, the spring member 30A is provided in the same manner as the spring member 30. That is, the spring member piece 36A is overlapped with the conductive members 20, 20A, and 20B in the same manner as a part of the corresponding spring member 30 of the spring member piece 36A. A plurality of conductive pieces 21 of the conductive members 20, 20A, and 20B come into contact with a plurality of spring pieces 31 of the spring member piece 36A. Similarly, a plurality of conductive pieces 21 of the conductive members 20, 20A, and 20B come into contact with a plurality of spring pieces 31 of the spring member piece 36B. Further, two gaps 37A and 37B are interposed between the spring member piece 36A and the spring member piece 36B overlapped with the conductive members 20, 20A, and 20B. Specifically, a gap 37A is interposed between the end 38Aa of the spring member piece 36A and the end 38Ba of the spring member piece 36B, and a gap 37B is interposed between the end 38Ab of the spring member piece 36A and the end 38Bb of the spring member piece 36B. In this way, the gap 37A is continuous with the end 38Aa of the spring member piece 36A and the end 38Ba of the spring member piece 36B, and the gap 37B is continuous with the end 38Ab of the spring member piece 36A and the end 38Bb of the spring member piece 36B.

[0087] The conductive ring 1 having the spring member 30A according to the modified example is also used in the same manner as the above-described conductive ring 1 to form a conductive path between the shaft 110 and the housing 111 of the electric motor 101. Further, the spring member 30A according to the modified example also acts in the same manner as the above-described conductive ring 1 and exhibits the same effects.

[0088] Also, in the conductive ring 1 having the spring member 30A according to the modified example, the spring member pieces 36A and 36B are arranged annularly with gaps 37A and 37B therebetween. For this reason, even if an external force is applied to the spring member pieces 36A and 36B due to the rotation of the shaft 110 in the use state, the spring member pieces 36A and 36B can escape into the gaps 37A and 37B. Therefore, it is possible to suppress the occurrence of deformation such as stress concentration and contact with the shaft 110 in the spring member pieces 36A and 36B. Thereby, damage to the spring member pieces 36A and 36B can be suppressed.

[0089] Also, when fixing the spring member pieces 36A and 36B to the holding member 10, the spring member pieces 36A and 36B can escape into the gaps 37A and 37B. Thereby, it is possible to suppress the occurrence of deformation such as wrinkles in the spring member pieces 36A and 36B when fixing the spring member pieces 36A and 36B to the holding member 10.

[0090] Next, another modification example of the spring member 30 will be described. FIG. 15 is a front view of a spring member 30B as another example of a modification example of the spring member 30. As shown in FIG. 15, the spring member 30B according to another modification example has one spring member piece 36C as the spring member piece 36 and one gap 37C as the gap 37. The spring member 30B does not have one of the gaps 37A or 37B, and the spring member piece 36A or 36B also extends to a part of one of the gaps 37A or 37B. The spring member piece 36A and the spring member piece 36B are connected at a part of one of the gaps 37A or 37B to form one spring member piece 36C. The spring member piece 36C of the spring member 30B extends, for example, on a circle or a substantially circular shape centered or substantially centered on the axis x as shown in FIG. 15, and the end 38Ca and the end 38Cb are opposed in the circumferential direction. Specifically, for example, they are opposed in a direction orthogonal to the axis x. The spring member piece 36C has a spring member piece 30C, which is a member corresponding to a part of the spring member 30, similar to the spring member pieces 36A and 36B. For example, the spring member piece 36C extends around the axis x with the same or substantially the same length as the conductive member piece 26C. That is, the spring member piece 36C and the conductive member piece 26C are configured such that the end 38Ca and the end 28Ca coincide or substantially coincide when viewed in the direction of the axis x, and can be overlapped with each other. Note that the spring member 30 may have three or more gaps 37 and three or more spring member pieces 36. Also in this case, the plurality of gaps 37 and the plurality of spring member pieces 36 are connected in a ring shape.

[0091] As described above, the present invention has been described through the above embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments. It is obvious to those skilled in the art that various changes or improvements can be made to the above embodiments. It is clear from the description of the claims that forms with such changes or improvements can also be included in the technical scope of the present invention.

[0092] The embodiments described above are for facilitating the understanding of the present invention and are not for limiting and interpreting the present invention. Also, the above-described embodiments do not limit the objects to which the present invention is applied, and the present invention can include any object as its application target. Each component included in the above embodiments, as well as its arrangement, material, conditions, shape, size, etc. are not necessarily limited to those exemplified, and can be changed as appropriate. For example, the present invention includes differences that occur in the implementation of manufacturing tolerances and the like. Also, components shown in different embodiments can be partially replaced or combined with each other within a range where there is no technical contradiction. Further, each configuration can be selectively combined as appropriate so as to achieve at least a part of the above-described problems and effects.

Description of Reference Numerals

[0093] 1 Conductive ring, 10 Holding member, 11 Inner holding member, 12 Fitting portion, 12a Outer peripheral surface, 13 Holding portion, 13a Inner peripheral end, 15 Outer holding member, 16 Fitting portion, 16a Inner peripheral surface, 17 Holding portion, 17a Inner peripheral end, 18 Pressing portion, 20, 20A, 20B Conductive member, 20a Inner peripheral end portion, 21 Conductive piece (end piece), 21a Inner peripheral end, 21b, 21c Side ends, 21d Outer peripheral end, 22 Base portion, 22a Inner peripheral end, 22b Outer peripheral end, 23 Gap, 24 Contact side surface, 25 Pressed side surface, 26, 26A, 26B, 26C Conductive member pieces, 27, 27A, 27B, 27C Gaps, 28a, 28Aa, 28Ba, 28Ca, 28b, 28Ab, 28Bb, 28Cb Ends, 30, 30A, 30B Spring members, 30a Inner peripheral end portion, 31 Spring piece (end piece), 31a Inner peripheral end, 31b, 31c Side ends, 31d Outer peripheral end, 32 Base portion, 32a Inner peripheral end, 32b Outer peripheral end, 33 Space, 34 Pressing side surface, 35 Rear surface, 36, 36A, 36B, 36C Conductive member pieces, 37, 37A, 37B, 37C Gaps, 38a, 38Aa, 38Ba, 38Ca, 38b, 38Ab, 38Bb, 38Cb Ends, 100, 200 Driving device, 101 Electric motor, 102 Reducer, 103 Inverter, 104 Battery, 105 Wheel, 110, 122 Shafts, 110a, 122a Outer peripheral surfaces, 111, 120 Housing, 121 Reduction gear stage, 112, 123 Bearings, 113, 124, 126 Shaft holes, 113a, 124a, 126a Inner peripheral surfaces, 125, 127 Oil seals, L1, L2 Lengths, R0 Radius, R1, R2, R3, R4, R5, R6 Distances (radii), T1, T2 Thicknesses, W1, W2, W3, W4 Widths, x Axis line, δ Interference fit

Claims

1. A holding member which is a member having annular conductivity around an axis, A conductive member which is a member having conductivity extending around the axis, A spring member extending around the axis, and The conductive member is formed of conductive PTFE having conductivity, and also has a plurality of end pieces arranged in the circumferential direction at the inner peripheral side end, The spring member has a plurality of end pieces arranged in the circumferential direction at the inner peripheral side end, Each of the plurality of end pieces of the spring member is adapted to elastically deform along the axis and also to contact the plurality of end pieces of the conductive member, The holding member holds the conductive member and the spring member side by side in the axial direction, The spring member is in contact with the conductive member and presses the conductive member, A conductive ring.

2. The plurality of end pieces of the spring member are arranged at intervals from each other in the circumferential direction, The conductive ring according to Claim 1.

3. 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, The conductive ring according to Claim 1.

4. The outer peripheral side ends of the plurality of end pieces of the spring member are located on the outer peripheral side of the outer peripheral side ends of the plurality of end pieces of the conductive member, The conductive ring according to Claim 1.

5. The spring member has a base which is an annular part, The plurality of end pieces of the spring member extend inward from the inner peripheral side end of the base of the spring member, The conductive ring according to Claim 1.

6. The plurality of end pieces of the conductive member are arranged at intervals from each other in the circumferential direction, The conductive ring according to Claim 1.

7. The conductive member has a base which is an annular part, The plurality of end pieces of the conductive member extend inward from the inner peripheral side end of the base of the conductive member, The conductive ring according to Claim 1.

8. 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, The conductive ring according to Claim 1.

9. The holding member is adapted to hold the conductive member and the spring member on the outer peripheral side, The conductive ring according to Claim 1.

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