Conduction structure and conduction assembly

Abstract

A conduction structure (2) comprises: a housing (3) that has a through hole (4) that is formed along an axis (x); a rotary shaft (5) that is supported inside the through hole (4) so as to be capable of rotating around the axis (x); and a conduction assembly (1) that is at least partially inside the through hole (4) and electrically connects the housing (3) and the rotary shaft (5). The conduction assembly (1) comprises: a conductive member (10) that is on one side (FS) in the direction of the axis (x) and contacts the rotary shaft (5); a conduction member (20) that is fitted into the through hole (4), holds the conductive member (10), and establishes conduction between the conductive member (10) and the housing (3); and a ventilation path (A) that establishes fluid communication between a first space (S1) of the through hole (4) that is further to another side (SS) that is opposite the one side (FS) than the conduction assembly (1) and a second space (S3) that is outside the through hole (4).

Description

Conductive structure and conductive assembly

[0001] The present invention relates to a conductive structure and a conductive assembly.

[0002] For example, in the drive motor of an electric vehicle, the presence of shaft voltage creates a potential difference between the outer and inner rings of the bearing that supports the shaft. The resulting shaft current causes electromagnetic noise on AM radio and electrolytic corrosion in the bearing. One known solution to this problem is a carbon brush that slides on the outer surface of the shaft adjacent to a sealing device such as an oil seal in the axial direction. By establishing electrical continuity between the shaft and the housing using the carbon brush, the shaft current can be released into the housing.

[0003] Japanese Patent Application Laid-Open No. 2015-147512

[0004] In this structure, the carbon brush extends radially, perpendicular to the axis of the rotating shaft, and contacts the outer circumferential surface of the rotating shaft. Therefore, space is required around the outer circumferential surface of the rotating shaft to accommodate the carbon brush and the components for attaching the carbon brush. This space increases the size of the drive motor, for example. On the other hand, if a sealing device such as an oil seal is placed inside the through-hole, negative pressure generated inside the through-hole can degrade the performance of the sealing device.

[0005] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a conductive structure and a conductive assembly that can secure an air passage while saving space.

[0006] A first aspect of the present invention provides a conductive structure comprising: a housing having a through hole formed along an axis; a rotating shaft supported within the through hole so as to be rotatable around the axis; and a conductive assembly arranged at least partially within the through hole and providing electrical conductivity between the housing and the rotating shaft, wherein the conductive assembly comprises: a conductive member arranged on one axial side along the axis and in contact with the rotating shaft; a conductive member fitted into the through hole to hold the conductive member and establish electrical conductivity between the conductive member and the housing; and an air passage providing fluid communication between a first space in the through hole on the other side opposite the one side of the conductive assembly and a second space outside the through hole.

[0007] The conductive assembly includes a conductive biasing member disposed within the conductive member and biasing the conductive member toward the end face on the one side of the rotating shaft.

[0008] The air passage has a gap formed between the outer peripheral surface of the conductive member and the inner peripheral surface of the conductive member, and an opening formed at the end of the one side of the conductive member.

[0009] The conduit assembly includes a porous vent member disposed in the opening to allow ventilation of the opening.

[0010] The conductive assembly includes an elastic member attached to the conductive member, and the elastic member is sandwiched between the outer surface of the conductive member and the inner surface of the through hole to seal the first space and the second space.

[0011] The conductive assembly includes a cover attached to the elastic member on one side of the elastic member, the elastic member having a plurality of protrusions that protrude from the one side and receive the cover, and the air passage includes a through hole in the elastic member that extends in the axial direction and is connected to the opening, and a flow path that extends radially between adjacent protrusions of the elastic member and is connected to the through hole.

[0012] The conductive member, the elastic member, and the cover are formed in an annular shape around the axis.

[0013] The cover has a cylindrical portion that forms an opening facing the flow path in the radial direction.

[0014] A gap is formed between the outer peripheral surface of the cylindrical portion and the inner peripheral surface of the through hole.

[0015] An end face of the cover on the one side is set flush with an end face of the housing on the one side.

[0016] The conductive assembly includes a conductor that electrically connects the conductive member and the conducting member to each other.

[0017] The conductive assembly has a rotation prevention mechanism that restricts relative rotation between the conductive member and the conductive member about the axis.

[0018] An annular sealing device is provided to seal the gap between the outer peripheral surface of the rotary shaft and the inner peripheral surface of the through hole.

[0019] A conductive assembly according to a second aspect of the present invention comprises a conductive member, a conductive conducting member that holds the conductive member, a cover that is arranged on one axial side of the conductive member and at least partially covers the through hole, and an air passage that fluidly connects the one side with the other side opposite the one side.

[0020] The conductive assembly includes a conductive biasing member disposed within the conductive member and biasing the conductive member toward the other side.

[0021] The air passage has a gap formed between the outer peripheral surface of the conductive member and the inner peripheral surface of the conductive member, and an opening formed at the end of the one side of the conductive member.

[0022] The conduit assembly includes a porous vent member disposed in the opening to allow ventilation of the opening.

[0023] The conductive assembly includes an elastic member arranged between the conductive member and the cover, the elastic member having a plurality of protrusions that protrude from one side and receive the cover, and the air passage has a through hole in the elastic member that extends in the axial direction and is connected to the opening, and a flow path that extends radially between adjacent protrusions of the elastic member and is connected to the through hole.

[0024] The conductive member, the elastic member, and the cover are formed in an annular shape around the axis.

[0025] The cover has a cylindrical portion that forms an opening facing the flow path in the radial direction.

[0026] The conductive assembly includes a conductor that electrically connects the conductive member and the conducting member to each other.

[0027] The conductive assembly includes a rotation prevention mechanism that restricts relative rotation between the conductive member and the conductive member about the axis.

[0028] A third aspect of the present invention provides a conductive structure comprising: a housing having a through hole formed along an axis; a rotating shaft supported within the through hole so as to be rotatable around the axis; and a conductive assembly at least partially disposed within the through hole to electrically connect the housing and the rotating shaft, wherein the conductive assembly comprises: a conductive member disposed on one axial side along the axis and in contact with the rotating shaft; a conductive member fitted into the through hole to hold the conductive member and establish electrical connection between the conductive member and the housing; a cover disposed on the one side of the conductive member and at least partially covering the through hole; and an air passage fluidically connecting a first space in the through hole on the other side opposite the one side of the conductive assembly to a second space outside the through hole.

[0029] The conductive assembly includes a conductive biasing member disposed within the conductive member and biasing the conductive member toward the end face on the one side of the rotating shaft.

[0030] The air passage has a gap formed between the outer peripheral surface of the conductive member and the inner peripheral surface of the conductive member, and an opening formed at the end of the one side of the conductive member.

[0031] The conduit assembly includes a porous vent member disposed in the opening to allow ventilation of the opening.

[0032] The conductive assembly includes an elastic member disposed between the conductive member and the cover, and the elastic member is partially sandwiched between the outer peripheral surface of the conductive member and the inner peripheral surface of the through hole to seal the first space and the second space.

[0033] The elastic member has a plurality of protrusions that protrude from one side and receive the cover, and the air passage has a through hole in the elastic member that extends in the axial direction and is connected to the opening, and a flow path that extends radially between adjacent protrusions of the elastic member and is connected to the through hole.

[0034] The conductive member, the elastic member, and the cover are formed in an annular shape around the axis.

[0035] The cover has a cylindrical portion that forms an opening facing the flow path in the radial direction.

[0036] A gap is formed between the outer peripheral surface of the cylindrical portion of the cover and the inner peripheral surface of the through hole.

[0037] An end face of the cover on the one side is set flush with an end face of the housing on the one side.

[0038] The conductive assembly includes a conductor that electrically connects the conductive member and the conducting member to each other.

[0039] The conductive assembly includes a rotation prevention mechanism that restricts relative rotation between the conductive member and the conductive member about the axis.

[0040] The conductive structure includes an annular sealing device that seals the gap between the outer circumferential surface of the rotary shaft and the inner circumferential surface of the through hole.

[0041] A fourth aspect of the present invention provides a conductive assembly comprising a conductive member, a conductive member that holds the conductive member, and a porous ventilation member that is disposed in an opening formed at an end of the conductive member on one axial side and allows ventilation through the opening, wherein the conductive member has a flange portion that can be engaged with an engaging portion of a jig that breaks through the ventilation member toward the other side opposite the one side and enters the conductive member.

[0042] The conductive assembly includes a conductive biasing member disposed within the conductive member and biasing the conductive member toward the other side.

[0043] The conductive assembly includes an elastic member attached to the conductive member on the one side, the elastic member having a through hole facing the opening in the axial direction.

[0044] The conductive assembly includes a cover that is removably attached to the elastic member on the one side, the elastic member having a plurality of protrusions that protrude from the one side and receive the cover, and the opening is connected to the through hole of the elastic member and a flow path of the elastic member that extends radially between adjacent protrusions and is connected to the through hole.

[0045] The conductive member, the elastic member, and the cover are formed in an annular shape around the axis.

[0046] The cover has a cylindrical portion that forms an opening facing the flow path in the radial direction.

[0047] The conductive assembly includes a conductor that electrically connects the conductive member and the conducting member to each other.

[0048] The conductive assembly includes a rotation prevention mechanism that restricts relative rotation between the conductive member and the conductive member about the axis.

[0049] A fifth aspect of the present invention provides a method for removing a conduction assembly in a conduction structure including a housing having a through hole formed along an axis, a rotating shaft supported within the through hole so as to be rotatable about the axis, and a conduction assembly at least partially disposed within the through hole to establish electrical continuity between the housing and the rotating shaft, the method comprising removing the conduction assembly from the through hole, the conduction assembly including a conductive member and a conductive member fitted in the through hole to hold the conductive member and establish electrical continuity between the conductive member and the housing. an air passage that fluidly connects a first space of the through hole in which the rotating shaft is disposed and a second space outside the through hole; and a porous ventilation member that is disposed in an opening that is formed at an end of the conductive member on the one side and forms the air passage, and allows ventilation of the opening, and the removal method includes the steps of: breaking through the ventilation member toward the other side opposite the one side, inserting a jig into the conductive member, and engaging a locking portion of the jig with a flange portion of the conductive member, thereby removing the conductive assembly from inside the through hole to the one side.

[0050] The conductive assembly includes an annular elastic member attached to the end of the conductive member, and in the step of removing the conductive assembly, the jig enters the conductive member from one side through the through hole and the opening of the elastic member.

[0051] The conductive assembly includes a cover removably attached to the elastic member on the one side of the elastic member, and the step of removing the conductive assembly includes the step of removing the cover from the elastic member.

[0052] The conductive member, the elastic member, and the cover are formed in an annular shape around the axis.

[0053] According to the present invention, it is possible to provide a conductive structure and a conductive assembly that can secure an air passage while saving space.

[0054] 8 is a perspective view schematically illustrating the structure of a conduction assembly 1 according to one embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line 2-2 of FIG. 1. FIG. 3 is a partially exploded perspective view schematically illustrating the structure of the conduction assembly 1 with the cover 50 removed. FIG. 4 is a partially enlarged cross-sectional view schematically illustrating the structure of a conduction structure 2 according to one embodiment of the present invention. FIG. 5 is a partially enlarged cross-sectional view corresponding to FIG. 4 and schematically illustrating an air passage A and a conduction route C. FIG. 6 is a partially enlarged cross-sectional view illustrating a mounting method for mounting the conduction assembly 1 in the through-hole 4 of the housing 3. FIG. 7 is a partially enlarged cross-sectional view illustrating a removal method for removing the conduction assembly 1 from the through-hole 4 of the housing 3. FIG. 8 is a partially enlarged cross-sectional view schematically illustrating the structure of a conduction structure 2A according to another embodiment of the present invention. FIG. 9 is a cross-sectional view taken along line 9-9 of FIG. 9. FIG. 10 is a cross-sectional view corresponding to FIG. 10 and schematically illustrating the structure of a conduction assembly 1B according to a modified example. FIG. 11 is a cross-sectional view schematically illustrating the structure of an example of a drive system as an example of an application target. FIG. 12 is a cross-sectional view schematically illustrating the structure of an example of a reducer as an example of an application target.

[0055] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view schematically illustrating the structure of a conduction assembly 1 according to one embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. 1. In one example, the conduction assembly 1 is incorporated into a machine such as a powertrain for transmitting rotational energy generated by a power source of an electric vehicle or electric motorcycle to a drive wheel. Alternatively, the conduction assembly may be incorporated into a drive motor or a reducer of a four-wheel or two-wheel vehicle, or into a motor used outdoors in a ship, construction machine, agricultural machine, or the like. Examples of applications of the conduction assembly 1 according to the present invention will be described later.

[0056] 1 and 2 , a conductive assembly 1 according to one embodiment is formed in an overall cylindrical shape with an axis x as its central axis. Hereinafter, one side in the direction along the axis x (hereinafter referred to as the “axial direction”) will be defined as a first side FS, and the other side in the axial direction opposite the first side FS will be defined as a second side SS. The conductive assembly 1 includes a conductive brush 10, a conductive member 20 that holds the conductive brush 10, a biasing member 30 that biases the conductive brush 10 toward the second side SS, an elastic member 40 coupled to the conductive member 20, and a cover 50 detachably attached to the elastic member 40. In this example, the conductive brush 10, the conductive member 20, the biasing member 30, the elastic member 40, and the cover 50 are coaxially arranged with the axis x as the center.

[0057] As shown in FIG. 2 , the conductive brush 10 includes a base 11 disposed on the first side FS, a main body 12 extending axially from the base 11 toward the second side SS, and a tip 13 extending axially from the main body 12 toward the second side SS. The base 11 is formed, for example, in a flat cylindrical shape about the axis x. The circular front surface on the first side FS and the annular back surface on the second side SS, which face each other, of the base 11, both extend along an imaginary plane perpendicular to the axis x. The main body 12 is formed in a cylindrical shape with a smaller diameter than the base 11. The tip 13 is formed in a truncated cone shape tapering from the main body 12 toward the second side SS. In this example, the tip surface 13a of the tip 13 on the second side SS is a flat surface extending along an imaginary plane perpendicular to the axis x. The tip surface 13a is defined as a circle. The base portion 11, the main body portion 12 and the tip portion 13 are integrally formed from a sintered material of a metallic material such as carbon, molybdenum dioxide, silver, etc. The conductive brush 10 is electrically conductive and self-lubricating.

[0058] The conductive member 20 includes an inner peripheral portion 21 disposed radially inward in a direction perpendicular to the axis x, and an outer peripheral portion 22 surrounding the inner peripheral portion 21 from the outer peripheral side. The inner peripheral portion 21 includes a cylindrical main body 23, an annular first flange portion 24, and an annular second flange portion 25. The main body 23 is formed in a cylindrical shape with the axis x as its central axis. The first flange portion 24 extends annularly from an end of the second side SS of the main body 23 toward the inner peripheral side. The second flange portion 25 extends annularly from an end of the first side FS of the main body 23 toward the inner peripheral side. In this example, the first flange portion 24 and the second flange portion 25 are formed by folding back both axial ends of a cylindrical member toward the inner peripheral side. The inner peripheral portion 21 is integrally formed from a conductive metal material, such as aluminum.

[0059] The inner peripheral portion 21 is configured to hold the conductive brush 10. The diameter defined by the outer peripheral surface of the base 11 of the conductive brush 10 is smaller than the diameter defined by the inner peripheral surface of the main body 23 of the inner peripheral portion 21. That is, a predetermined gap is formed between the outer peripheral surface of the base 11 of the conductive brush 10 and the inner peripheral surface of the main body 23 of the inner peripheral portion 21. Furthermore, the diameter defined by the outer peripheral surface of the main body 12 is smaller than the diameter defined by the opening 24a formed by the inner peripheral edge of the first flange portion 24. That is, a predetermined gap is formed between the outer peripheral surface of the main body 12 of the conductive brush 10 and the opening 24a of the first flange portion 24. Meanwhile, the diameter of the outer peripheral surface of the base 11 is larger than the diameter of the opening 24a. As a result, the annular back surface of the second side SS of the base 11 is received on the surface of the first side FS of the first flange portion 24. In this manner, the first flange portion 24 supports the base 11. The conductive brush 10 is prevented from falling off from the inner circumferential portion 21 to the second side SS.

[0060] A biasing member 30 is housed within the inner circumferential portion 21 between the base 11 and the second flange 25 of the conductive brush 10. The biasing member 30 is an elastic body, such as a coil spring, that has electrical conductivity. The vicinity of the end of the biasing member 30 on the first side FS contacts the back surface of the second side SS of the second flange 25. Meanwhile, the vicinity of the end of the biasing member 30 on the second side SS contacts the surface of the base 11. In this example, the inner diameter of the biasing member 30 is larger than the diameter of the opening 25a formed by the inner circumferential edge of the second flange 25. The biasing member 30 biases the conductive brush 10 toward the second side SS by its elastic restoring force. The base 11 of the conductive brush 10 is received by the first flange 24 of the inner circumferential portion 21. Meanwhile, when the conductive brush 10 is displaced axially toward the first side FS against the elastic restoring force of the biasing member 30, a larger elastic restoring force accumulates in the biasing member 30. In this way, the conductive brush 10 is held by the conductive member 20 in a state where it is always biased toward the second side SS.

[0061] The outer peripheral portion 22 is coupled to the inner peripheral portion 21. The outer peripheral portion 22 includes a large-diameter cylindrical portion 26, a small-diameter cylindrical portion 27 having a diameter smaller than that of the large-diameter cylindrical portion 26, and an annular third flange portion 28. The large-diameter cylindrical portion 26 and the small-diameter cylindrical portion 27 are connected by an annular step 29. The small-diameter cylindrical portion 27 is located closer to the first side FS than the large-diameter cylindrical portion 26. The inner circumferential surface of the small-diameter cylindrical portion 27 is fitted to the outer circumferential surface of the main body 23 of the inner peripheral portion 21, for example, by press fitting. The third flange portion 28 extends annularly from the end of the small-diameter cylindrical portion 27 on the first side FS toward the inner circumferential side. A predetermined gap is formed axially between the second flange portion 25 and the third flange portion 28. An opening 28a formed by the inner circumferential edge of the third flange portion 28 faces the opening 25a of the second flange portion 25 in the axial direction. The outer peripheral portion 22 is integrally formed from a conductive metal material, for example, aluminum.

[0062] An elastic member 40 is coupled to the outer peripheral portion 22. The elastic member 40 has an annular first portion 41 around the axis x, an annular second portion 42 extending from the outer peripheral end of the first portion 41 toward the second side SS, and a plurality of protrusions 43 protruding from the annular surface of the first portion 41 toward the first side FS. The elastic member 40 is attached, for example, using an adhesive to the surface of the first side FS of the third flange portion 28 of the outer peripheral portion 22 and the outer peripheral surface of the small-diameter cylindrical portion 27. In this example, the first portion 41 also covers a portion of the back surface of the second side SS around the opening 28a of the third flange portion 28. The elastic member 40 is integrally formed from synthetic rubber, for example, nitrile rubber (NBR), hydrogenated nitrile rubber (H-NBR), acrylic rubber (ACM), fluorocarbon rubber (FKM), or other such rubber.

[0063] The first portion 41 has a through hole 44 formed along the axis x. As described below, the through hole 44 forms a flow path that allows fluid to flow. In this example, the through hole 44 is formed coaxially with the opening 25 a of the inner peripheral portion 21 and the opening 28 a of the outer peripheral portion 22 of the conductive member 20. Meanwhile, the second portion 42 covers the outer peripheral surface of the small-diameter cylindrical portion 27 of the outer peripheral portion 22. In this example, the diameter of the outer peripheral surface of the second portion 42 is set to be equal to or larger than the diameter of the outer peripheral surface of the large-diameter cylindrical portion 26 of the outer peripheral portion 22. Note that the radial thickness defined between the outer peripheral surface and the inner peripheral surface of the second portion 42 is preferably set to be such that, when the conductive assembly 1 is placed in a through hole of a housing described below, the second portion 42 is radially compressed between the inner peripheral surface of the through hole and the outer peripheral surface of the small-diameter cylindrical portion 27.

[0064] FIG. 3 is a partially exploded perspective view schematically illustrating the structure of the conduction assembly 1 with the cover 50 removed. Referring to FIGS. 1 to 3 , in this example, multiple protrusions 43 are arranged on the surface of the first portion 41 of the elastic member 40 in a circumferential direction defined around the axis x. Each protrusion 43 is formed, for example, in an oval shape when viewed from the first side FS. The upper surface of the first side FS of each protrusion 43 is defined, for example, as a flat surface extending along an imaginary plane perpendicular to the axis x. The height of the upper surface from the surface of the first portion 41 is set equal for all protrusions 43. Radial flow paths 45 are formed between adjacent protrusions 43 in the circumferential direction. The flow paths 45 extend radially from the axis x. The flow paths 45 connect a space on the inner circumferential side of the first portion 41 to a space on the outer circumferential side. The flow paths 45 are connected to the through-holes 44 in the first portion 41. As long as the flow passages 45 are formed between the protrusions 43, 43 adjacent to each other in the circumferential direction, the protrusions 43 may have other shapes and may have other numbers.

[0065] A cover 50 is detachably attached to the elastic member 40. In this example, the cover 50 has a disk portion 51 and a cylindrical portion 52 that cylindrically protrudes from the outer peripheral end of the disk portion 51 toward the second side SS. The disk portion 51 is formed, for example, in a flat disk shape around the axis x. In this example, the front surface of the first side FS and the back surface of the second side SS of the disk portion 51, which face each other, extend along an imaginary plane perpendicular to the axis x. The cover 50 is detachably coupled to the elastic member 40 by fitting the cylindrical portion 52 into the first portion 41 of the elastic member 40. When the cover 50 is coupled to the elastic member 40, as shown in FIG. 2 , the back surface of the second side SS of the disk portion 51 is received by the upper surfaces of the multiple protrusions 43 of the elastic member 40. In this way, each flow path 45 is surrounded by the circumferentially adjacent protrusions 43, 43, the first portion 41, and the disk portion 51 of the cover 50.

[0066] The cylindrical portion 52 of the cover 50 is formed with a plurality of recesses (openings) 53 recessed from the end of the second side SS of the cylindrical portion 52 toward the first side FS. In this example, the recesses 53 are arranged circumferentially. Specifically, the circumferential position of each recess 53 corresponds to the circumferential position of each flow path 45 formed by the protrusions 43, 43 of the elastic member 40. That is, each recess 53 faces each flow path 45 in the radial direction. In this manner, the through hole 44 and the flow path 45 of the elastic member 40 can fluidly communicate the space within the conductive member 20 with the space outside the conductive assembly 1 through the openings 25 a and 28 a of the conductive member 20 and the recesses 53. The cover 50 is integrally formed, for example, from a metal material or a resin material. Note that, instead of the recesses 53, the cylindrical portion 52 may be formed with an opening having a continuously extending edge, for example.

[0067] Returning to FIG. 2 , the conductive member 20, the elastic member 40, and the cover 50 are all formed in an annular shape around the axis x. The opening 25a of the second flange 25 of the inner circumferential portion 21 of the conductive member 20 is covered by the ventilation member 60. In this example, the ventilation member 60 is formed in a circular shape with a diameter larger than the opening 25a. The ventilation member 60 is attached to the surface of the first side FS of the second flange portion 25 and is sandwiched between the second flange portion 25 and the third flange portion 28 of the outer circumferential portion 22. In this example, a part of the first portion 41 of the elastic member 40 is sandwiched between the ventilation member 60 and the third flange portion 28. The first portion 41 is compressed in the axial direction between the ventilation member 60 and the third flange portion 28, thereby pressing the ventilation member 60 against the surface of the second flange portion 25. In this way, the ventilation member 60 can block the opening 25a.

[0068] The ventilation member 60 is a breathable member that allows air to flow between the space formed within the conductive member 20 and the space formed by the elastic member 40 and the cover 50. The ventilation member 60 is formed, for example, from a hydrophobic, water-repellent, or oil-repellent porous body. The porous body may be formed, for example, from a fluororesin. The porous body is a porous body having fine pores that are gas permeable. For example, the ventilation member 60 may be a nonwoven fabric formed from expanded PTFE (polytetrafluoroethylene) or the like. However, other materials may also be used for the ventilation member 60. The ventilation member 60 may be bonded to the surface of the second flange portion 25 of the inner circumferential portion 21 using an adhesive, or may be sandwiched between the second flange portion 25 and the first portion 41 of the elastic member 40 without using an adhesive.

[0069] Next, a conduction structure 2 according to one embodiment of the present invention will be described below. FIG. 4 is a partially enlarged cross-sectional view schematically illustrating the structure of the conduction structure 2 according to one embodiment of the present invention. As shown in FIG. 4 , the conduction structure 2 includes a housing 3, a rotating shaft 5 disposed in a through hole 4 of the housing 3, an annular sealing device 7 that seals a gap G formed between an inner circumferential surface 4 a of the through hole 4 and an outer circumferential surface 5 a of the rotating shaft 5, and a conduction assembly 1 disposed in the through hole 4 adjacent to a first side FS of the rotating shaft 5 in the axial direction. In this example, the rotating shaft 5 is a shaft of an electric motor or the like. The axis x of the conduction assembly 1 coincides with the rotation axis of the rotating shaft 5. The housing 3 and the rotating shaft 5 are formed from a conductive metallic material.

[0070] The through hole 4 of the housing 3 is, for example, a cylindrical space extending along the axis x. That is, the inner circumferential surface 4 a of the through hole 4 is a cylindrical surface with the axis x as its central axis. On the other hand, the rotation shaft 5 is, for example, a cylindrical rotation shaft extending along the axis x. The outer circumferential surface 5 a of the rotation shaft 5 is a cylindrical surface with the axis x as its central axis. The through hole 4 and the rotation shaft 5 are coaxial. A gap G extends annularly between the inner circumferential surface 4 a of the through hole 4 and the outer circumferential surface 5 a of the rotation shaft 5. In this example, the axis x of the conduction assembly 1 coincides with the rotation axis of the rotation shaft 5, so the conduction assembly 1 and the rotation shaft 5 are coaxial. As will be described later, the conduction assembly 1 is attached by being press-fitted into the through hole 4.

[0071] The sealing device 7 is, for example, an oil seal. The sealing device 7 has an annular reinforcing ring 70 centered on the axis x and an annular elastic body portion 71 centered on the axis x. The elastic body portion 71 is integrally attached to the reinforcing ring 70. The reinforcing ring 70 is formed, for example, from a metal material. The elastic body portion 71 is formed, for example, from an elastic body such as synthetic rubber. The reinforcing ring 70 has a cylindrical portion 72 centered on the axis x and a disk-shaped flange portion 73 extending from the end of the first side FS of the cylindrical portion 72 toward the inner periphery. The elastic body portion 71 has a side cover 74, an axial cover 75, and a lip portion 76. The side cover 74, the axial cover 75, and the lip portion 76 are integrally formed.

[0072] The side cover 74 covers the outer peripheral surface of the cylindrical portion 72 of the reinforcing ring 70. The side cover 74 is compressed radially between the inner peripheral surface 4a of the through hole 4 of the housing 3 and the cylindrical portion 72. Meanwhile, the axial cover 75 covers the surface of the first side FS of the flange portion 73 of the reinforcing ring 70. The lip portion 76 also has a seal lip 77 and a dust lip 78. The seal lip 77 has a wedge shape that is convex toward the inner peripheral side. The seal lip 77 is formed to slide in close contact with the outer peripheral surface 5a of the rotating shaft 5. A spring 79 is attached to the outer peripheral side of the seal lip 77. The spring 79 applies a predetermined amount of tension to the seal lip 77 against the outer peripheral surface 5a of the rotating shaft 5.

[0073] The through hole 4 defines a space S1 on a first side FS of the sealing device 7 and a space S2 on a second side SS of the sealing device 7. The above-described conductive assembly 1 is disposed in the space S1. As described below, the space S1 is fluidly connected to the external space by an air passage formed in the conductive assembly 1. As a result, air can be drawn into the space S1 from the external space. On the other hand, oil for lubrication and cooling is sealed in the space S2. The seal lip 77 of the sealing device 7 slides on the outer circumferential surface 5a of the rotating shaft 5, thereby sealing the oil in the space S2 from the air in the space S1. On the other hand, the dust lip 78 can prevent foreign matter such as dust from entering from the first space S1 toward the seal lip 77.

[0074] In this example, the conduction assembly 1 is mounted in the through hole 4 of the housing 3 from the first side FS. During mounting, the large-diameter cylindrical portion 26 of the outer circumferential portion 22 of the conductive member 20 is press-fitted into the through hole 4. At the same time, the second portion 42 of the elastic member 40 is press-fitted into the through hole 4. The second portion 42 is radially compressed between the inner circumferential surface 4a of the through hole 4 and the outer circumferential surface of the small-diameter cylindrical portion 27, thereby sealing the gap between the outer circumferential surface of the second portion 42 and the inner circumferential surface 4a of the through hole 4. In other words, no airflow is permitted between the outer circumferential surface of the second portion 42 and the inner circumferential surface 4a of the through hole 4. The conduction assembly 1 is mounted in the through hole 4 so that the end face of the first side FS of the conduction assembly 1 (i.e., the surface of the first side FS of the disk portion 51 of the cover 50) is flush with the end face 3a of the first side FS of the housing 3.

[0075] In the conductive assembly 1 thus installed in the through hole 4, the tip surface 13a of the tip portion 13 of the conductive brush 10 abuts against the end surface 5b on the first side FS of the rotating shaft 5. In this example, the end surface 5b extends along an imaginary plane perpendicular to the axis x. Since the tip surface 13a also extends along an imaginary plane perpendicular to the axis x, the entire tip surface 13a contacts the end surface 5b. As the tip surface 13a abuts against the end surface 5b, the conductive brush 10 is pushed axially into the conductive member 20 on the first side FS. The base 11 of the conductive brush 10 moves away from the first flange portion 24 of the inner periphery 21 toward the first side FS. As a result, an elastic restoring force accumulates in the biasing member 30. This elastic restoring force of the biasing member 30 keeps the conductive brush 10 pressed against the end surface 5b of the rotating shaft 5.

[0076] In the conductive assembly 1 installed in the through hole 4, the space within the inner peripheral portion 21 is connected to the first space S1 through an annular gap formed between the outer peripheral surface of the base 11 of the conductive brush 10 and the inner peripheral surface of the body 23 of the inner peripheral portion 21. Meanwhile, the space within the cover 50 is connected to the space S3 outside the housing 3 through an annular gap formed between the outer peripheral surface of the cylindrical portion 52 of the cover 50 and the inner peripheral surface 4a of the through hole 4. The space within the inner peripheral portion 21 is also connected to the through hole 44 and the flow path 45 of the elastic member 40 through the openings 25a and 28a of the conductive member 20. The ventilation member 60 is permeable. As a result, as shown in FIG. 5 , an air passage A is formed that extends from the first space S1 through the gap between the base 11 and the body 23, then through the openings 25a and 28a, the through hole 44, the flow path 45, and the recess 53 to the third space S3. This air passage A introduces air into the space S1.

[0077] Returning to FIG. 4 , in the electrical conduction structure 2, when the rotating shaft 5 rotates around the axis x, the seal lip 77 and dust lip 78 of the sealing device 7 slide over the outer peripheral surface 5 a of the rotating shaft 5. In this way, the sealing device 7 seals the oil in the space S2 from the atmosphere in the space S1 while simultaneously preventing foreign matter such as dust from entering from the first space S1 toward the seal lip 77. Meanwhile, the tip surface 13 a of the tip end 13 of the conductive brush 10 of the electrical conduction assembly 1 slides over the end surface 5 b of the rotating shaft 5 around the axis x. If an induced current (i.e., an axial current) is generated through the rotating shaft 5 due to the presence of an axial voltage, a conduction route C is established from the rotating shaft 5 through the conductive brush 10, the biasing member 30, the inner and outer peripheral portions 21 and 22 of the conductive member 20, and the housing 3, as shown in FIG. 5 . As a result, electromagnetic noise from AM radios and electrolytic corrosion of bearings in an electric vehicle incorporating the electrical conduction structure 2 can be suppressed.

[0078] In the above-described conduction assembly 1, components including the conductive brush 10, the conductive member 20, the elastic member 40, and the cover 50 are arranged in the axial direction. An air passage A formed through these components fluidly connects the first space S1 in the through hole 4 to the third space S3 outside the housing 3. As a result, atmospheric air is introduced into the first space S1, preventing negative pressure from being generated in the first space S1. This prevents a decrease in the performance of the sealing device 7. However, if negative pressure were to be generated in the first space S1, oil would leak from the seal lip 77 of the sealing device 7 into the first space S1. In this conduction assembly 1, all components are arranged in the axial direction, allowing the conduction assembly 1 to be completely housed within the through hole 4 that accommodates the rotating shaft 5. The conduction structure 2 having the housing 3 achieves space-saving while ensuring the air passage A.

[0079] In the conductive structure 2, the conductive assembly 1 is press-fitted into the through-hole 4 by the large-diameter cylindrical portion 26 of the outer circumferential portion 22 and the second portion 42 of the elastic member 40. By radially compressing the second portion 42 of the elastic member 40, the second portion 42 seals the gap between the outer circumferential surface of the small-diameter cylindrical portion 27 and the inner circumferential surface 4a of the through-hole 4. Meanwhile, in the conductive assembly 1, the air passage A is secured by components including the conductive brush 10, the conductive member 20, the elastic member 40, and the cover 50. In the conductive assembly 1, the components including the conductive brush 10, the conductive member 20, the elastic member 40, and the cover 50 are integrally formed in the axial direction. This allows for a significant reduction in the number of components compared to conventional techniques that require components other than the conductive brush to form the air passage.

[0080] Furthermore, the conduction assembly 1 is completely housed within the through hole 4. In this example, the surface of the cover 50 of the conduction assembly 1 is set flush with the end surface 3a of the housing 3. With this configuration, the cover 50 can prevent muddy water, sand, dust, and the like from entering the conduction assembly 1 from the outside. However, despite the presence of the cover 50, the conduction assembly 1 still has an air vent path A. The air vent path A connects the first space S1 within the through hole 4 with the external third space S3. Therefore, the conduction assembly 1 can ensure both the conduction route C of the axial current and the air vent path A. Furthermore, since a ventilation member 60 is disposed in the ventilation path A, air can circulate, while the ventilation member 60 can prevent muddy water, sand, dust, and the like from entering the conduction member 20 from the recess 53 of the cover 50 through the flow path 45 and the through hole 44.

[0081] FIG. 6 is a partially enlarged cross-sectional view illustrating a method for installing the conductive assembly 1 in the through-hole 4 of the housing 3. As shown in FIG. 6, the conductive assembly 1 is prepared in a state in which all components are pre-assembled. When the conductive assembly 1 is press-fitted into the through-hole 4, an end face 81 of a jig 80 for pressing the conductive assembly 1 into the through-hole 4 is pressed against the surface of the cover 50 of the conductive assembly 1. The end face 81 extends along an imaginary plane perpendicular to the axis x. When the end face 81 of the jig 80 contacts the end face 3a of the housing 3, the surface of the cover 50 of the conductive assembly 1 is set flush with the end face 3a of the housing 3. At this time, the tip face 13a of the tip end 3 of the conductive brush 10 is pressed against the end face 5b of the rotating shaft 5, thereby pressing the conductive brush 10 into the conductive member 20. An elastic restoring force is accumulated in the biasing member 30. Installation of the conductive assembly 1 is thus completed. The conductive assembly 1, which is an integrated assembly, can be easily installed in the through-hole 4.

[0082] FIG. 7 is a partially enlarged cross-sectional view illustrating a method for removing the conductive assembly 1 from the through hole 4 of the housing 3. Removal of the conductive assembly 1 is performed, for example, during maintenance or disassembly of the device. First, the cover 50 is removed from the conductive assembly 1. For example, the cover 50 is removed by inserting the tip of a screwdriver or pliers into the recess 53 of the cover 50 through the gap between the cover 50 and the through hole 4. Then, as shown in FIG. 7 , the tip of a jig 90 is inserted through the through hole 44 of the elastic member 40 so as to break through the ventilation member 60. The jig 90 is, for example, an elongated member having a hook-shaped engaging portion 91 at its tip. Inside the conductive member 20, the engaging portion 91 of the jig 90 engages with the second flange portion 25 of the inner periphery 21. In this state, the jig 90 is pulled out toward the first side FS, whereby the conductive assembly 1 without the cover 50 is removed outward from the through hole 4. In this way, the conductive assembly 1, which is an integral assembly, can be easily removed from the through hole 4.

[0083] FIG. 8 is a partially enlarged cross-sectional view schematically illustrating the structure of a conduction structure 2A according to another embodiment of the present invention. FIG. 9 is a cross-sectional view taken along line 9-9 in FIG. 8. As shown in FIGS. 8 and 9, a conduction assembly 1A according to another embodiment of the present invention is attached to the through hole 4 of the housing 3 of this conduction structure 2A. Note that FIG. 9 shows a cross-section of only the conduction assembly 1A. This conduction structure 2A can establish a conduction route C1 that is different from the conduction route C established in the previously described conduction structure 2. Note that in the conduction structure 2A, the conduction assembly 1A has a different configuration from the conduction assembly 1, while the configuration other than the conduction assembly 1A is the same. In FIGS. 8 and 9, components similar to those in the previously described embodiment are designated by the same reference numerals, and redundant description will be omitted here.

[0084] In the conductive assembly 1A, a notch 23a is formed extending from the opening 24a of the first flange portion 24 of the inner periphery 21 to the main body 23. As shown in FIG. 9 , in this example, the notch 23a is formed at only one location around the axis x. The base 11 of the conductive brush 10 has a protrusion 11a extending radially outward through the notch 23a. The protrusion 11a and the outer periphery 22 are electrically connected by a conductor 8. The conductor 8 is made of a conductive metal material. The conductor 8 is, for example, a copper wire. In this example, the conductor 8 extends from the outer periphery end of the protrusion 11a to the first side FS and is electrically connected to the outer periphery 22 near a step 29 of the outer periphery 22. The length of the conductor 8 is set to be greater than the distance between the protrusion 11a and the step 29 when the conductive brush 10 is displaced axially to the second side SS to its maximum extent. In this way, electrical connection by the conductor 8 is reliably ensured even when the conductive brush 10 is displaced in the axial direction.

[0085] In this conductive structure 2A, a conductive route C1 is established from the rotating shaft 5 through the conductive brush 10, the conductor 8, the outer periphery 22 of the conductive member 20, and the housing 3. Compared to the conductive route C, which passes only through the biasing member 30, the conductor 8 is formed of a copper wire that directly electrically connects the conductive brush 10 and the conductive member 20. This allows for lower electrical resistance along the conductive route C1 than the conductive route C alone. Furthermore, the circumferential edge of the notch 23a in the inner periphery 21 is circumferentially adjacent to the protrusion 11a. When the tip surface 13a of the tip end 13 of the conductive brush 10 slides over the end surface 5b of the rotating shaft 5, the sliding resistance between the tip surface 13a and the end surface 5b causes the conductive brush 10 to rotate together with the rotating shaft 5 around the axis x. In this case, the protrusion 11a of the base 11 of the conductive brush 10 contacts the edge of the notch 23a, restricting rotation of the conductive brush 10 around the axis x. That is, the protrusion 11a and the notch 23a constitute a rotation prevention mechanism that restricts the rotation of the conductive brush 10 around the axis x.

[0086] FIG. 10 corresponds to FIG. 9 and is a cross-sectional view schematically illustrating the structure of a conductive assembly 1B according to a modified example. This conductive assembly 1B improves the anti-rotation function for restricting rotation of the conductive brush 10 in the conductive assembly 1A. Specifically, as shown in FIG. 10 , recesses 11b recessed toward the inner periphery are formed on the outer circumferential surface of the base 11 of the conductive brush 10. In this example, three recesses 11b are provided circumferentially spaced apart on the outer circumferential surface of the base 11. The recesses 11b are formed, for example, to curve toward the inner periphery. Meanwhile, one or more protrusions 23b (three in this example) protruding toward the inner periphery are formed on the main body 23 of the inner periphery 21 at positions corresponding to the recesses 11b. The protrusions 23b are formed to curve toward the recesses 11b. The protrusions 23b engage with the recesses 11b. The recess 11b and the protrusion 23b constitute a rotation prevention mechanism that restricts the rotation of the conductive brush 10 around the axis x.

[0087] Next, an application of the conductive assemblies 1, 1A, and 1B will be described. FIG. 11 is a cross-sectional view schematically illustrating the structure of an example of a drive system as an example of the application. The drive system 100 is, for example, a drive system for an electric vehicle. As shown in FIG. 11 , the example drive system 100 includes a motor 101 as a drive source and a reducer 102 that changes the speed of the driving force transmitted from the motor 101 and outputs it. The motor 101 includes a housing 103 and a rotating shaft 105 rotatably supported by the housing 103 via a pair of bearings 104. A rotor 106 is fixed to the outer circumferential surface of the rotating shaft 105, while a stator 107 is fixed to the inner circumferential surface of the housing 103. A conductive assembly 1 (1A, 1B) press-fitted into a through-hole 103a of the housing 103 is installed on one end of the rotating shaft 105. In this example, a sealing device 7 and a resolver 108 are disposed between the conductive assembly 1 and the bearing 104. Furthermore, a sealing device 7 is disposed adjacent to the bearing 104 on the other end side of the rotating shaft 105. The sealing device 7 disposed in this manner seals in grease, such as a lubricant, filled in the bearing 104.

[0088] The reducer 102 has a case 110, a first reducer shaft 111, a second reducer shaft 112, and a drive shaft 113. The first reducer shaft 111, the second reducer shaft 111, and the drive shaft 113 are rotatably supported by the case 110 via bearings 114. The first reducer shaft 111 is connected to the other end of the rotating shaft 105 of the motor 101, and the driving force of the motor 101 is transmitted to the reducer 102. The second reducer shaft 111 is connected to the drive shaft 113 via a differential gear 115, a differential pinion shaft 116, a differential side gear 117, and a differential pinion gear 118. In this way, the driving force of the motor 101 is changed in speed and transmitted to the drive shaft 113. In this reducer 102, a sealing device 7 is disposed adjacent to the end of the first reducer shaft 111 on the motor 101 side. Furthermore, a sealing device 7 is disposed adjacent to a bearing 114 that supports the drive shaft 113. The sealing device 7 disposed in this manner seals the oil or grease filled inside the case 110 of the reducer 102.

[0089] Furthermore, the conduction assembly 1 (1A, 1B) may be incorporated into the reducer 102 in addition to or instead of the motor 101. Fig. 12 is a cross-sectional view schematically showing the structure of an example of a reducer as an example of an application target. In this example, the conduction assembly 1 is arranged so as to contact the other end of the first reducer shaft 111. In this reducer 102, a sealing device 7 is arranged adjacent to the other end of the first reducer shaft 111. The sealing device 7 arranged in this manner seals the oil or grease filled inside the case 110 of the reducer 102.

[0090] Although the present invention has been described above through the above embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the claims that such modifications and improvements can also be included within the technical scope of the present invention.

[0091] The above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. Furthermore, the above-described embodiments do not limit the scope of application of the present invention, but may include any object to which the present invention can be applied. The components of the above-described embodiments, as well as their arrangement, materials, conditions, shape, size, etc., are not limited to those exemplified and can be modified as appropriate. For example, the present invention includes differences that arise during implementation due to manufacturing tolerances, etc. Furthermore, components shown in different embodiments can be partially substituted or combined with each other to the extent that they are not technically inconsistent. Furthermore, the various configurations can be selectively combined as appropriate to achieve at least some of the above-described problems and effects.

[0092] 1, 1A, 1B Conductive assembly, 2, 2A Conductive structure, 3 Housing, 3a End face, 4 Through hole, 4a Inner peripheral surface, 5a Outer peripheral surface, 5 Rotating shaft, 5b End face, 7 Sealing device, 8 Conductor, 10 Conductive brush (conductive member), 11 Base, 11a Protrusion, 11b Recess, 12 Main body, 13 Tip portion, 13a Tip face, 20 Conductive member, 21 Inner peripheral portion, 22 Outer peripheral portion, 23 Main body, 23a Notch, 23b Convex portion, 24 First flange portion, 24a Opening, 25 Second flange portion, 26 Large diameter cylindrical portion, 27 Small diameter cylindrical portion, 28 Third flange portion, 28a Opening, 29 Step, 30 Urging member, 40 Elastic member, 41 First portion, 42 Second portion, 43 Protrusion, 44 Through hole, 45 Flow path, 50 Cover, 51 Disk portion, 52 Cylindrical portion, 53 Recess (opening), 60 Ventilation member, 70 Reinforcing ring, 71 Elastic portion, 72 Cylindrical portion, 73 Flange portion, 74 Side cover, 75 Axial cover, 76 Lip portion, 77 Seal lip, 78 Dust lip, 79 Spring, 80 Jig, 81 End face, 90 Jig, 91 Locking portion, 100 Drive system, 101 Motor, 102 Reducer, 103 Housing, 104 Bearing, 105 Rotating shaft, 106 Rotor, 107 Stator, 103a Through hole, 108 Resolver, 110 Case, 111 First reducer shaft, 112 Second reducer shaft, 113 Drive shaft, 114 Bearing, 115 Differential gear, 116 Differential pinion shaft, 117 differential side gear, 118 differential pinion gear, A ventilation path, C, C1 conduction route, FS first side, G gap, S1 space (first space), S2 space, S3 space (second space), SS second side, x axis

Claims

1. A conductive structure comprising: a housing having a through hole formed along an axis; a rotating shaft supported within the through hole so as to be rotatable about the axis; and a conductive assembly at least partially disposed within the through hole and providing electrical continuity between the housing and the rotating shaft, wherein the conductive assembly comprises: a conductive member disposed on one axial side along the axis and in contact with the rotating shaft; a conductive member fitted into the through hole to hold the conductive member and establish electrical continuity between the conductive member and the housing; and an air passage providing fluid communication between a first space in the through hole on the other side opposite the one side of the conductive assembly and a second space outside the through hole.

2. The conductive structure according to claim 1, wherein the conductive assembly includes a conductive biasing member disposed within the conductive member and biasing the conductive member toward the end face on the one side of the rotating shaft.

3. The conductive structure according to claim 1, wherein the air passage has a gap formed between the outer peripheral surface of the conductive member and the inner peripheral surface of the conductive member, and an opening formed at the end of the one side of the conductive member.

4. The conduit structure according to claim 3, wherein said conduit assembly comprises a porous ventilation member disposed in said opening to allow ventilation of said opening.

5. The conduction structure according to claim 3, wherein the conduction assembly comprises an elastic member attached to the conductive member, and the elastic member is sandwiched between the outer peripheral surface of the conductive member and the inner peripheral surface of the through hole to seal the first space and the second space.

6. The conduction structure according to claim 5, wherein the conduction assembly comprises a cover attached to the elastic member on said one side of the elastic member, the elastic member having a plurality of protrusions that protrude from said one side and receive the cover, and the air passage has a through hole in the elastic member that extends in the axial direction and is connected to the opening, and a flow path that extends in the radial direction between adjacent protrusions of the elastic member and is connected to the through hole.

7. The conductive structure according to claim 6, wherein the conductive member, the elastic member, and the cover are formed in a ring shape around the axis.

8. The conduction structure according to claim 6, wherein the cover has a cylindrical portion that forms an opening facing the flow path in the radial direction.

9. The electrical connection structure according to claim 8, wherein a gap is formed between the outer peripheral surface of the cylindrical portion and the inner peripheral surface of the through hole.

10. The conduction structure according to claim 6, wherein an end face of said cover on said one side is defined flush with an end face of said housing on said one side.

11. The conductive structure of claim 1, wherein the conductive assembly comprises a conductor electrically connecting the conductive member and the conducting member to each other.

12. The electrical connection structure according to claim 11, wherein the electrical connection assembly includes a rotation prevention mechanism that restricts relative rotation between the conductive member and the conducting member about the axis.

13. The conduction structure according to claim 1, further comprising an annular sealing device for sealing between the outer peripheral surface of the rotating shaft and the inner peripheral surface of the through hole.

14. A conductive assembly comprising: a conductive member; a conductive conducting member that holds the conductive member; a cover that is arranged on one axial side of the conducting member and at least partially covers the through hole; and an air passage that fluidly connects the one side with another side opposite the one side.

15. The continuity assembly of claim 14, wherein the continuity assembly includes a conductive biasing member disposed within the conductive member to bias the conductive member toward the other side.

16. The conduction assembly according to claim 14, wherein the air passage has: a gap formed between the outer peripheral surface of the conductive member and the inner peripheral surface of the conductive member; and an opening formed at the end of the one side of the conductive member.

17. The conduit assembly of claim 16, wherein the conduit assembly includes a porous vent member disposed in the opening to allow ventilation of the opening.

18. A conduction assembly as described in claim 16, further comprising an elastic member disposed between the conduction member and the cover, the elastic member having a plurality of protrusions that protrude from the one side and receive the cover, and the air passage having a through hole in the elastic member that extends in the axial direction and is connected to the opening, and a flow path that extends in the radial direction between adjacent protrusions of the elastic member and is connected to the through hole.

19. The conduction assembly of claim 18, wherein the conduction member, the elastic member, and the cover are formed in an annular shape around the axis.

20. The conduit assembly according to claim 18, wherein the cover has a cylindrical portion that forms an opening facing the flow path in a radial direction.

21. The conduit assembly of claim 14, wherein the conduit assembly comprises a conductor electrically connecting the conductive member and the conducting member to one another.

22. The conduction assembly according to claim 21, further comprising a rotation prevention mechanism that restricts relative rotation between the conductive member and the conducting member about the axis.

23. A conductive structure comprising: a housing having a through hole formed along an axis; a rotating shaft supported within the through hole so as to be rotatable around the axis; and a conductive assembly at least partially disposed within the through hole and providing electrical continuity between the housing and the rotating shaft, wherein the conductive assembly comprises: a conductive member disposed on one axial side along the axis and in contact with the rotating shaft; a conductive member fitted into the through hole to hold the conductive member and establish electrical continuity between the conductive member and the housing; a cover disposed on the one side of the conductive member and at least partially covering the through hole; and an air passage providing fluid communication between a first space in the through hole on the other side opposite the one side of the conductive assembly and a second space outside the through hole.

24. The conduction structure according to claim 23, wherein the conduction assembly includes a conductive biasing member disposed within the conductive member and biasing the conductive member toward the end face on the one side of the rotating shaft.

25. The conductive structure described in claim 23, wherein the ventilation path has a gap formed between the outer peripheral surface of the conductive member and the inner peripheral surface of the conductive member, and an opening formed at the end of the one side of the conductive member.

26. The conduit structure of claim 25, wherein the conduit assembly includes a porous vent member disposed in the opening to allow ventilation of the opening.

27. The conduction structure described in claim 24, wherein the conduction assembly includes an elastic member disposed between the conductive member and the cover, and the elastic member is partially sandwiched between the outer peripheral surface of the conductive member and the inner peripheral surface of the through hole to seal the first space and the second space.

28. A conductive structure as described in claim 27, wherein the elastic member has a plurality of protrusions that protrude from the one side and receive the cover, and the air passage has a through hole in the elastic member that extends in the axial direction and is connected to the opening, and a flow path that extends radially between adjacent protrusions of the elastic member and is connected to the through hole.

29. The electrical connection structure according to claim 28, wherein the electrical connection member, the elastic member, and the cover are formed in an annular shape around the axis.

30. The conduction structure according to claim 28, wherein the cover has a cylindrical portion that forms an opening facing the flow path in the radial direction.

31. The electrical connection structure according to claim 30, wherein a gap is formed between the outer peripheral surface of the cylindrical portion of the cover and the inner peripheral surface of the through hole.

32. The electrical continuity structure according to claim 23, wherein an end face of the cover on said one side is defined flush with an end face of the housing on said one side.

33. The conductive structure of claim 23, wherein the conductive assembly comprises a conductor electrically connecting the conductive member and the conducting member to each other.

34. The electrical connection structure according to claim 33, wherein the electrical connection assembly includes a rotation prevention mechanism that restricts relative rotation between the conductive member and the conducting member about the axis.

35. The conduction structure according to claim 23, comprising an annular sealing device that seals the gap between the outer circumferential surface of the rotating shaft and the inner circumferential surface of the through hole.

36. A conductive assembly comprising: a conductive member; a conductive member that holds the conductive member; and a porous ventilation member that is disposed in an opening formed in an end of the conductive member on one axial side and allows ventilation through the opening, wherein the conductive member has a flange portion that can be engaged with an engaging portion of a jig that breaks through the ventilation member toward the other side opposite the one side and enters the conductive member.

37. The continuity assembly of claim 36, wherein the continuity assembly includes a conductive biasing member disposed within the conductive member to bias the conductive member toward the other side.

38. The conduction assembly according to claim 36, wherein the conduction assembly comprises an elastic member attached to the conduction member on the one side, the elastic member having a through hole facing the opening in the axial direction.

39. A conduction assembly as described in claim 38, wherein the conduction assembly comprises a cover that is detachably attached to the elastic member on the one side, the elastic member has a plurality of protrusions that protrude from the one side and receive the cover, and the opening is connected to the through hole of the elastic member and a flow path of the elastic member that extends radially between adjacent protrusions and is connected to the through hole.

40. The conduit assembly of claim 39, wherein the conduit member, the elastic member, and the cover are formed in an annular shape around the axis.

41. A conduit assembly as set forth in claim 39, wherein the cover has a cylindrical portion that forms an opening facing the flow path in a radial direction.

42. The continuity assembly of claim 36, wherein the continuity assembly comprises a conductor electrically connecting the conductive member and the conducting member to one another.

43. The conduction assembly according to claim 42, wherein the conduction assembly includes a rotation prevention mechanism that restricts relative rotation between the conductive member and the conducting member about the axis.

44. A method for removing a conductive assembly from a conductive structure comprising: a housing having a through hole formed along an axis; a rotating shaft supported within the through hole so as to be rotatable about the axis; and a conductive assembly disposed at least partially within the through hole and providing electrical continuity between the housing and the rotating shaft, the conductive assembly comprising: a conductive member; a conductive member fitted into the through hole to hold the conductive member and establish electrical continuity between the conductive member and the housing; an air passage providing fluid communication between a first space in the through hole in which the rotating shaft is disposed and a second space outside the through hole; and a porous ventilation member disposed in an opening formed at one end of the conductive member and forming the air passage, allowing ventilation of the opening. The removal method includes the step of inserting a jig into the conductive member by breaking through the ventilation member toward the other side opposite the one side, and engaging a locking portion of the jig with a flange portion of the conductive member, thereby removing the conductive assembly from within the through hole to the one side.

45. A method for removing a conductive assembly as described in claim 44, wherein the conductive assembly comprises an annular elastic member attached to the end of the conductive member, and in the step of removing the conductive assembly, the jig enters the conductive member from the one side through the through-hole and the opening of the elastic member.

46. ​​A method for removing a conduction assembly as described in claim 45, wherein the conduction assembly includes a cover removably attached to the elastic member on the one side of the elastic member, and the method includes the step of removing the cover from the elastic member prior to the step of removing the conduction assembly.

47. The method for removing a conductive assembly according to claim 46, wherein the conductive member, the elastic member, and the cover are formed in an annular shape around the axis.

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