Brush unit and connection device

Abstract

A brush unit is brought into contact with a shaft conductive portion provided to a rotating shaft, and the frame and the shaft conductive portion are electrically connected. The brush unit includes a holder, a brush brought into contact with the shaft conductive portion via a first opening portion provided to the holder, a spring, a sleeve that is a cylindrical member that holds the brush, an electrode, and a wiring that connects the brush and the electrode. The electrode is sandwiched by a second protruding portion of the holder and the sleeve.

Description

Technical Field

[0001] This disclosure relates to a brush unit and a connecting device for electrically connecting a rotating shaft and a conductor. Background Technology

[0002] A rotating shaft driven by an electric motor may sometimes become electrified. The charge carried by the rotating shaft becomes current and flows in the bearing that supports the rotating shaft, which may sometimes cause electrolytic corrosion in the bearing. In order to prevent current from flowing in the bearing, for example, in Patent Document 1, a brush unit is brought into contact with the end of the rotating shaft. Moreover, it is described that the charge carried by the rotating shaft flows to a conductive material such as a housing via the brush unit.

[0003] Prior art literature Patent documents Patent Document 1: Japanese Patent No. 6242566 Summary of the Invention The problem that the invention aims to solve Patent Document 1 does not describe in detail the structure of the brush unit that allows current to flow from a conductor along the rotation axis. Therefore, in this technical field, there is a need for a brush unit that can ensure a stable conductive path with higher conductivity, and a connection device having such a brush unit.

[0004] Solution for solving the problem The brush unit disclosed herein is [1] "A brush unit is mounted on a conductor and abuts against a shaft conductive portion disposed on a rotating shaft to electrically connect the conductor and the shaft conductive portion. The brush unit comprises: a retainer, mounted on the conductor and having conductivity, having a receiving space on its inner side; a brush, disposed in the receiving space, abutting against the shaft conductive portion via a first opening provided in the retainer, having conductivity; a force-applying portion, applying force to the brush toward the side where the first opening is located; and a cylindrical sleeve, disposed in the receiving space, having the brush disposed inside, and holding the brush so that it can apply force to the brush on the force-applying portion." The device slides in a certain direction; has an electrode that is conductive; and wiring that connects the brush and the electrode. The retainer has: a retainer body portion disposed to surround the sleeve and having a cylindrical structure extending along the direction of force application of the force application portion to the brush, with one end opening of the cylindrical structure serving as a first opening; and a second extension portion extending inward from a second opening portion on the retainer body portion, the second extension portion facing the end face of the sleeve on the side where the second opening portion is located in the direction of force application of the force application portion to the brush, the electrode being held by the second extension portion and the sleeve.

[0005] In this brush unit, a cage mounted on a conductor and abutting against a shaft conductive portion mounted on a rotating shaft are electrically connected to each other via wiring and electrodes. Furthermore, the electrodes are held by a second extension of the cage and a sleeve. Thus, the electrodes and the cage are stably electrically connected to each other. In this way, the brush unit ensures a stable conductive path with higher conductivity.

[0006] The brush unit disclosed herein can also be [2] "According to the brush unit described in [1] above, the retainer further has a first protrusion extending inward from the first opening in the retainer body portion, the first protrusion facing the end face of the sleeve on the side where the first opening is located in the direction of force application of the force application portion to the brush, the sleeve and the electrode being held by the first protrusion and the second protrusion." In this case, the electrode and the sleeve are held together by the first protrusion and the second protrusion, thereby achieving a more reliable electrical connection with the retainer.

[0007] The brush unit disclosed herein can also be [3] "According to the brush unit described in [2] above, a first oil passage hole is provided in the first protrusion, a second oil passage hole is provided in the second protrusion, and a sleeve oil passage hole extending along the force-applying direction of the force-applying part to the brush is provided in the portion between the inner and outer circumferential surfaces of the sleeve." In this case, in the brush unit, an oil passage connecting the conductor and the rotating shaft is formed through the first oil passage hole, the sleeve oil passage hole, and the second oil passage hole. Thus, the brush unit can also be used as an oil passage for supplying lubricating oil or other oil to flow between the conductor and the rotating shaft.

[0008] The brush unit disclosed herein can also be [4] "According to the brush unit described in [1] above, the retainer body portion is provided with a retainer oil passage hole that connects the outer peripheral surface and the inner peripheral surface of the retainer body portion, and the outer peripheral surface of the sleeve is provided with an outer oil passage groove that extends along the force application direction of the force application portion on the brush." ​​In this case, in the brush unit, an oil passage connecting the conductor and the rotating shaft side is formed through the retainer oil passage hole and the outer oil passage groove. In addition, at the end of the retainer on the first opening side, oil passes through the gap between the outer peripheral surface of the brush and the retainer. In this way, the brush unit can also be used as an oil passage for supplying lubricating oil and other oils to flow between the conductor and the rotating shaft.

[0009] The brush unit disclosed herein can also be [5] "According to the brush unit described in [1] above, the retainer body is provided with a retainer oil passage hole that connects the outer peripheral surface and the inner peripheral surface of the retainer body, the inner peripheral surface of the sleeve is provided with an inner oil passage groove that extends along the force application direction of the force application part on the brush, and the sleeve is also provided with an inlet oil passage hole that connects the outer peripheral surface of the sleeve and the inner oil passage groove." In this case, in the brush unit, an oil passage connecting the conductor and the rotating shaft side is formed through the retainer oil passage hole, the inlet oil passage hole and the inner oil passage groove. In addition, at the end of the retainer on the first opening side, oil passes through the gap between the outer peripheral surface of the brush and the retainer. In this way, the brush unit can also be used as an oil passage for supplying lubricating oil and other oils to flow between the conductor and the rotating shaft.

[0010] The brush unit disclosed herein may be [6] "The brush unit according to any one of [1] to [5] above, wherein the electrode is elastically deformable in the clamping direction of the second extension and the sleeve, and is clamped by the second extension and the sleeve in a compressed state. In this case, the electrode applies force to the second extension of the cage by means of the force required for the electrode to return to its original shape. As a result, in the brush unit, the contact between the electrode and the cage is improved, and the electrode can be electrically connected to the second extension of the cage more stably."

[0011] The brush unit disclosed herein can also be [7] "the brush unit according to any one of [1] to [6] above, wherein the outer edge of the electrode is clamped by the retainer body and the second protrusion at the corner where the retainer body and the second protrusion intersect." Thus, in the brush unit, by clamping the outer edge of the electrode, the electrode can be more securely fixed. Therefore, in the brush unit, the electrode and the retainer can be electrically connected more stably.

[0012] The connection device disclosed herein is [8] "a connection device for electrically connecting a rotating shaft and a conductor, the connection device comprising: a shaft conductive portion installed at the end of the rotating shaft and having conductivity; and a brush unit as described in any one of [1] to [7] above, one end of the brush unit abutting against the shaft conductive portion, and the other end being installed on the conductor, thereby electrically connecting the shaft conductive portion and the conductor."

[0013] The connecting device includes the aforementioned brush unit. Therefore, as described above, the connecting device ensures a stable conductive path with higher conductivity.

[0014] The effects of the invention According to this disclosure, a stable conductive path with higher conductivity can be ensured. Attached Figure Description

[0015] Figure 1 It is a cross-sectional view around the rotating shaft with the connecting device installed.

[0016] Figure 2 (a) is Figure 1 An enlarged cross-sectional view of the brush unit. Figure 2 (b) is an enlarged cross-sectional view showing the state of the brush unit's cage before machining.

[0017] Figure 3 yes Figure 1 An exploded perspective view of the brush unit.

[0018] Figure 4 This is a cross-sectional view of the brush unit in the first modified example.

[0019] Figure 5 This is an exploded perspective view of the brush unit in the first modified example.

[0020] Figure 6 This is a cross-sectional view of the brush unit in the second variation.

[0021] Figure 7 This is an exploded perspective view of the brush unit in the second variation.

[0022] Figure 8 This is a cross-sectional view of the brush unit in the third variation.

[0023] Figure 9 This is an exploded perspective view of the brush unit in the third variation.

[0024] Figure 10 This is a cross-sectional view of the brush unit in the fourth variation.

[0025] Figure 11 This is a cross-sectional view of the brush unit in the fifth variation. Detailed Implementation

[0026] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Furthermore, in the drawings, the same or equivalent elements are given the same reference numerals, and repeated descriptions are omitted.

[0027] like Figure 1 As shown, the connecting device 1 electrically connects the rotating shaft 2, supported by the bearing 3 and capable of rotation, to the frame (conductor) 4. The rotating shaft 2 can be the shaft of an electric motor, or it can be a shaft connected to the shaft of an electric motor via gears. In this embodiment, the portion of the rotating shaft 2 at end 2a is a hollow shaft (hollow structure). Alternatively, the rotating shaft 2 can be entirely hollow, not just at end 2a. The bearing 3 supports the rotating shaft 2 so that it can rotate about the rotation axis L. The type of bearing 3 is not particularly limited as long as it can support the rotating shaft 2 to allow rotation.

[0028] The frame 4 houses the connecting device 1, the rotating shaft 2, and the bearing 3, etc. The frame 4 is conductive. In this embodiment, the connecting device 1 electrically connects the rotating shaft 2 to the frame 4. As a result, the connecting device 1 forms a conductive path with a lower resistance value than the conductive path from the rotating shaft 2 through the bearing 3 to the frame 4.

[0029] like Figure 1 As shown, the connecting device 1 includes a shaft conductive portion 10 and a brush unit 20. The shaft conductive portion 10 is conductive. In addition, the shaft conductive portion 10 is shaped with a recess 10a. The shaft conductive portion 10 is mounted on the end 2a of the rotating shaft 2 with the opening 10b of the recess 10a facing outward.

[0030] More specifically, the axial conductive portion 10 includes a ball retainer 11 and a steel ball 12. Both the ball retainer 11 and the steel ball 12 are conductive. The ball retainer 11 has a shape with a recess 10a. As an example, the ball retainer 11 is formed by stamping a steel plate.

[0031] The steel ball 12 can be, for example, a ball bearing. The steel ball 12 is mounted on the bottom 10c of the recess 10a of the ball cage 11. Here, as an example, the steel ball 12 is embedded in a hole in the bottom 10c of the recess 10a of the ball cage 11 and fixed by tightening. Thus, the steel ball 12, located on the bottom 10c of the recess 10a of the shaft conductive portion 10, forms a convex abutment portion that abuts against the brush unit 20 (the end face S of the brush 22). The steel ball 12 is mounted on the ball cage 11 with its center located on the rotation axis L, which serves as the rotation center of the rotation shaft 2.

[0032] On the outer peripheral surface of the ball retainer 11, there is an insertion portion 11a that is embedded and fixed to the inner peripheral surface 2b of the end 2a of the rotating shaft 2. The ball retainer 11 is embedded and fixed to the inner peripheral surface 2b of the end 2a of the rotating shaft 2 with the opening 10b of the recess 10a facing outward. The insertion portion 11a of the ball retainer 11 and the inner peripheral surface 2b of the rotating shaft 2 engage with each other. Therefore, the ball retainer 11 rotates integrally with the rotating shaft 2. The steel ball 12 abuts against one end of the brush unit 20 (end face S of the brush 22) within the recess 10a of the ball retainer 11.

[0033] One end of the brush unit 20 is inserted into the recess 10a of the shaft conductive portion 10, abutting against the steel ball 12 disposed at the bottom 10c of the recess 10a. The other end of the brush unit 20 is mounted on the frame 4. The brush unit 20 is electrically connected to the shaft conductive portion 10 mounted on the rotating shaft 2 and the frame 4. More specifically, as... Figure 2 (a) and Figure 3As shown, the brush unit 20 includes a retainer 21, a brush 22, a spring (force application part) 23, a sleeve 24, an electrode 25, and wiring 26.

[0034] The retainer 21 is conductive. As an example, a conductive metal (steel) can be used as the material for the retainer 21. A receiving space R is provided inside the retainer 21. A first opening H21a is provided in the retainer 21. The end of the retainer 21 with the first opening H21a is inserted into the recess 10a of the shaft conductive part 10. The other end of the retainer 21 is mounted on the frame 4. In this embodiment, the frame 4 has a recess 4a on the rotation axis L, which is the rotation center of the rotation shaft 2 (see reference). Figure 1 The retainer 21 is mounted on the frame 4 by inserting into the recess 4a at the other end. Thus, the frame 4 and the retainer 21 are electrically connected to each other.

[0035] The brush 22 is housed within the housing space R of the retainer 21. The brush 22 is conductive. The brush 22 is capable of sliding along the rotation axis L within the retainer 21. As an example, a carbon brush can be used as the brush 22. In this embodiment, the brush 22 is cylindrical about the rotation axis L. However, the brush 22 is not limited to a cylindrical shape and can also be prismatic, such as a quadrilateral. By making the brush 22 cylindrical, it is easy to form the brush 22.

[0036] The brush 22 abuts against the shaft conductive portion 10 via a first opening H21a provided in the retainer 21. More specifically, in the brush 22, the end face S of the bottom 10c side (steel ball 12 side) of the recess 10a of the shaft conductive portion 10 abuts against the steel ball 12. That is, the end face S becomes the contact surface that abuts against the steel ball 12. The shape of the end face S can be flat, concave (for example, a concave arc shape), or convex (for example, a convex arc shape). In this embodiment, the end face S only needs to be able to make point contact with the steel ball 12.

[0037] Furthermore, as described above, the steel ball 12 is positioned such that its center is located on the rotation axis L. Therefore, the end face S of the brush 22 and the steel ball 12 are in point contact with each other on the rotation axis L. Consequently, even if the shaft conductive portion 10 rotates together with the rotating shaft 2, the position of the contact point between the end face S of the brush 22 and the steel ball 12 will not shift. That is, at the connection point between the end face S and the steel ball 12, the difference in their circumferential velocities is zero.

[0038] Spring 23 is housed within the housing space R. Spring 23 is conductive. As an example, spring 23 is a helical compression spring. Spring 23 applies force to brush 22 towards the first opening H21a of the holder 21. That is, spring 23 applies force to brush 22 in the direction that brush 22 approaches steel ball 12. As a result, brush 22 makes point contact with steel ball 12 when the connecting device 1 is installed. That is, brush 22 and steel ball 12 are electrically connected.

[0039] The sleeve 24 is housed within the receiving space R. The sleeve 24 can be made of resin or a conductive metal. The sleeve 24 is cylindrical. In this embodiment, the sleeve 24 is cylindrical. A brush 22 and a spring 23 are disposed inside the sleeve 24. The sleeve 24 extends in the direction in which the spring 23 applies force to the brush 22. The sleeve 24 holds the brush 22 so that it can slide in the direction in which the spring 23 applies force to the brush 22.

[0040] Here, the retainer 21 has a first protrusion 21a, a second protrusion 21b, and a retainer body 21c. The retainer body 21c is provided to surround the sleeve 24. The retainer body 21c is cylindrical, extending in the direction of the force applied by the spring 23 to the brush 22. In this embodiment, the retainer body 21c is cylindrical. That is, the sleeve 24 is disposed inside the retainer body 21c. In the retainer body 21c, the end opening on one side of the cylindrical shape is called the first opening H21a. In the retainer body 21c, the end opening on the opposite side to the first opening H21a is called the second opening H21b.

[0041] The first extension 21a extends inward from the first opening H21a of the retainer body 21c. A predetermined gap is provided between the end of the first extension 21a in the extension direction and the outer peripheral surface of the brush 22. The first extension 21a faces the end face of the sleeve 24 on the side of the first opening H21a in the direction in which the spring 23 applies force to the brush 22.

[0042] The second extension 21b extends inward from the second opening H21b of the retainer body 21c. The second extension 21b faces the end face of the sleeve 24 on the side of the second opening H21b in the direction in which the spring 23 applies force to the brush 22.

[0043] Electrode 25 is conductive. Electrode 25 is housed within a housing space R and abuts against the second protrusion 21b. Electrode 25 has a protrusion 25a projecting toward the brush 22. Spring 23 is disposed between electrode 25 and brush 22. The end of spring 23 is embedded in the outer side of protrusion 25a. Protrusion 25a allows for positioning of spring 23.

[0044] Electrode 25 has a larger outer shape than the hole inside sleeve 24. The outer edge of electrode 25 is held by the second extension 21b of retainer 21 and sleeve 24 in the direction of force applied by spring 23 to brush 22. In this embodiment, sleeve 24 and electrode 25 are held by the first extension 21a and the second extension 21b of retainer 21 in the direction of force applied by spring 23 to brush 22.

[0045] One end of wiring 26 is connected to electrode 25. The other end of wiring 26 is connected to brush 22. Wiring 26 electrically connects electrode 25 and brush 22. Wiring 26 is flexible, for example. Wiring 26 maintains the electrical connection between electrode 25 and brush 22 even when the spacing between electrode 25 and brush 22 changes.

[0046] Wiring 26 is inserted into the inside of the coil-shaped spring 23. With both ends of wiring 26 connected to the electrode 25 and the brush 22 respectively, the brush 22, spring 23, electrode 25, and wiring 26 are integrated. Thus, the brush unit 20 can improve the assemblability when assembling the brush 22, spring 23, electrode 25, and wiring 26 relative to the cage 21.

[0047] The brush 22 is connected to the electrode 25 via wiring 26. The electrode 25 is fixed to the holder 21 by being clamped by the second extension 21b and the sleeve 24. Thus, the brush 22 will not fall off the holder 21 when the steel ball 12 is not in contact with the brush 22 (for example, when assembling the brush unit 20 into the frame 4 and before assembling the brush unit 20).

[0048] In addition, such as Figure 2 As shown in (b), the second protrusion 21b can also be formed by bending (e.g., hot rolling) the end 21d of the cage body portion 21c (which becomes the second protrusion 21b) while each component is housed in the housing space R of the cage 21.

[0049] Furthermore, the electrode 25 is configured to elastically deform in the clamping direction between the second protrusion 21b and the sleeve 24. The electrode 25 is clamped by the second protrusion 21b and the sleeve 24 in a compressed state. For example, Figure 2 (b) shows the state where electrode 25 is not clamped by the second protrusion 21b and sleeve 24. Figure 2 As shown in (b), as an example of a structure capable of elastic deformation in the clamping direction, the portion of electrode 25 clamped by the second protrusion 21b and the sleeve 24 can also be inclined or bent relative to the end face of the sleeve 24. When the second protrusion 21b is formed by bending, it compresses the electrode 25 by pressing the inclined or bent portion of the electrode 25 against the end face of the sleeve 24, and clamps the electrode 25 by the sleeve 24.

[0050] In this embodiment, the second protrusion 21b extends over the entire circumferential region of the end of the cage body portion 21c. That is, the second protrusion 21b is annular. However, it is not limited to this; one or multiple second protrusions 21b may be provided along the circumference of the second opening H21b of the cage body portion 21c. Similarly, the first protrusion 21a is not limited to being annular. One or multiple first protrusions 21a may be provided along the circumference of the first opening H21a of the cage body portion 21c.

[0051] Next, the conductive path between the rotating shaft 2 and the frame 4 when using the connecting device 1 will be explained. In this embodiment, the ball holder 11, steel ball 12, holder 21, brush 22, electrode 25, and wiring 26 are conductive. Therefore, the rotating shaft 2 is electrically connected to the frame 4 via the ball holder 11, steel ball 12, brush 22, wiring 26, electrode 25, and holder 21. That is, the ball holder 11, steel ball 12, brush 22, wiring 26, electrode 25, and holder 21 form the conductive path for electrically connecting the rotating shaft 2 and the frame 4. In addition, in this embodiment, the spring 23 is conductive. Therefore, the spring 23 can also become a conductive path between the brush 22 and the electrode 25. Thus, even when the rotating shaft 2 is rotating, the rotating shaft 2 is electrically connected to the frame 4.

[0052] As described above, in this brush unit 20, the retainer 21 mounted on the frame 4 and the brush 22, which abuts against the shaft conductive portion 10 mounted on the rotating shaft 2, are electrically connected to each other via wiring 26 and electrode 25. Furthermore, the electrode 25 is held by the second extension 21b of the retainer 21 and the sleeve 24. Thus, the electrode 25 and wiring 26 are stably electrically connected to each other. In this way, the brush unit 20 and the connecting device 1 equipped with the brush unit 20 can ensure a stable conductive path with higher conductivity.

[0053] The retainer 21 has a first protrusion 21a extending inward from the first opening H21a in the retainer body portion 21c, and a second protrusion 21b extending inward from the second opening H21b in the retainer body portion 21c. The sleeve 24 and the electrode 25 are held by the first protrusion 21a and the second protrusion 21b. In this case, the electrode 25 is held together with the sleeve 24 by the first protrusion 21a and the second protrusion 21b, thereby achieving a more reliable electrical connection with the sleeve 24.

[0054] The electrode 25 is held in a compressed state by the second extension 21b and the sleeve 24. In this case, the electrode 25 exerts force on the second extension 21b of the holder 21 using the force required for the electrode 25 to return to its original shape. As a result, the contact between the electrode 25 and the second extension 21b of the holder 21 is improved in the brush unit 20, and the electrical connection between the electrode 25 and the second extension 21b can be made more stable.

[0055] (First variation) Next, a first modified example of the brush unit will be described. For example... Figure 4 and Figure 5 As shown, in the first modified example, the brush unit 20A replaces the retainer 21 and sleeve 24 of the above embodiment, and has a retainer 21A and sleeve 24A with different structures. A retainer oil passage hole 21e connecting the outer and inner peripheral surfaces of the retainer body portion 21c of the retainer 21A is provided. Additionally, an oil passage is provided in the frame 4. The oil passage provided in the frame 4 opens into the wall surface of the recess 4a in which the brush unit 20A is embedded. The retainer oil passage hole 21e provided in the retainer 21A communicates with the oil passage provided in the frame 4.

[0056] An inner oil passage groove 24a is provided on the inner circumferential surface of the sleeve 24A. The inner oil passage groove 24a extends along the direction of the force applied by the spring 23 to the brush 22. In this embodiment, multiple inner oil passage grooves 24a are provided on the inner circumferential surface of the sleeve 24A. In addition, an inlet oil passage hole 24b is provided on the sleeve 24A to connect the outer circumferential surface of the sleeve 24A and the inner oil passage groove 24a. The inlet oil passage hole 24b is provided in a direction orthogonal to the direction of the force applied by the spring 23 to the brush 22, and is positioned opposite to the retainer oil passage hole 21e. In addition, an oil passage groove 24c extending circumferentially is provided on the outer circumferential surface of the sleeve 24A at the opening of the inlet oil passage hole 24b. Thus, even if the inlet oil passage hole 24b is not opposite to the retainer oil passage hole 21e provided on the retainer 21, it can communicate with the retainer oil passage hole 21e via the oil passage groove 24c.

[0057] In addition, the first extension 21a is provided with an extension length from the cage body 21c so that the oil flowing in the inner oil passage groove 24a can pass between the end of the first extension 21a and the outer peripheral surface of the brush 22.

[0058] In this configuration, the brush unit 20A forms an oil passage connecting the frame 4 and the rotating shaft 2, as indicated by arrow Y1, through the holder oil passage hole 21e, the inlet oil passage hole 24b, and the inner oil passage groove 24a. Furthermore, at the end of the holder 21A on the side of the first opening H21a, oil passes through the gap between the outer peripheral surface of the brush 22 and the holder 21A (the end of the first protrusion 21a). The oil flow direction can also be opposite to that indicated by arrow Y1. In the shaft conductive part 10, oil passage holes are simply provided around the steel ball 12 to allow oil to flow from the brush unit 20A side into the interior of the rotating shaft 2. Thus, the brush unit 20A can also be used as an oil passage for supplying lubricating oil or other oils between the frame 4 and the rotating shaft 2.

[0059] (Second variation) Next, a second variation of the brush unit will be described. For example... Figure 6 and Figure 7 As shown, in the second variation, the brush unit 20B replaces the retainer 21 and sleeve 24 of the above embodiment, and has a retainer 21B and sleeve 24B with different structures. A first oil passage hole 21f is provided in the first protrusion 21a of the retainer 21B. In this embodiment, multiple first oil passage holes 21f are provided in the first protrusion 21a. A second oil passage hole 21g is provided in the second protrusion 21b of the retainer 21B. In this embodiment, multiple second oil passage holes 21g are provided in the second protrusion 21b. Furthermore, an oil passage is provided in the frame 4. The oil passage provided in the frame 4 opens into the wall surface of the recess 4a in which the brush unit 20B is embedded. The second oil passage hole 21g provided in the retainer 21B communicates with the oil passage provided in the frame 4.

[0060] In the sleeve 24B, a sleeve oil passage hole 24e is provided in the portion between the inner and outer peripheral surfaces of the sleeve 24B, extending in the direction of the force applied by the spring 23 to the brush 22. In this embodiment, multiple sleeve oil passage holes 24e are provided around the central hole (the hole for receiving the brush 22, etc.) of the cylindrical sleeve 24. The sleeve oil passage hole 24e penetrates through the sleeve 24B in the direction of the force applied by the spring 23 to the brush 22. In addition, the electrode 25 is sized to not block the sleeve oil passage hole 24e provided in the sleeve 24B.

[0061] The second oil passage 21g provided in the second extension 21b of the retainer 21B and the sleeve oil passage 24e provided in the sleeve 24B are interconnected. The first oil passage 21f provided in the first extension 21a of the retainer 21B and the sleeve oil passage 24e provided in the sleeve 24B are interconnected. The sleeve 24B is housed in the receiving space R such that the second oil passage 21g communicates with the sleeve oil passage 24e, and the first oil passage 21f communicates with the sleeve oil passage 24e. However, the sleeve 24B may also have a circumferentially extending groove on the end face facing the second extension 21b. The second oil passage 21g and the sleeve oil passage 24e may also communicate with each other through this groove. Similarly, the sleeve 24B may also have a circumferentially extending groove on the end face facing the first extension 21a. The first oil passage 21f and the sleeve oil passage 24e may also communicate with each other through this groove.

[0062] In this configuration, the brush unit 20B forms an oil passage, as indicated by arrow Y2, connecting the frame 4 and the rotating shaft 2 via the second oil passage 21g, the sleeve oil passage 24e, and the first oil passage 21f. Alternatively, the oil flow direction can be opposite to that indicated by arrow Y2. In the shaft conductive part 10, oil passage holes can be provided around the steel ball 12 to allow oil to flow from the brush unit 20B side into the interior of the rotating shaft 2. Thus, the brush unit 20B can also be used as an oil passage for supplying lubricating oil or other oils between the frame 4 and the rotating shaft 2.

[0063] (Third variation) Next, a third variation of the brush unit will be described. For example... Figure 8 and Figure 9 As shown, the brush unit 20C in the third modification replaces the retainer 21 and sleeve 24 of the above embodiment, and has a retainer 21C and sleeve 24C with different structures. A retainer oil passage hole 21e connecting the outer and inner peripheral surfaces of the retainer body portion 21c of the retainer 21C is provided. The brush unit 20C of this modification has the same structure as the brush unit 20A of the first modification. Furthermore, an oil passage is provided in the frame 4. The oil passage provided in the frame 4 opens into the wall surface of the recess 4a in which the brush unit 20C is embedded. The retainer oil passage hole 21e provided in the retainer 21C communicates with the oil passage provided in the frame 4.

[0064] An outer oil passage groove 24f is provided on the outer peripheral surface of the sleeve 24C. The outer oil passage groove 24f extends along the direction of the force applied by the spring 23 to the brush 22. In this embodiment, multiple outer oil passage grooves 24f are provided on the outer peripheral surface of the sleeve 24C. The retainer oil passage hole 21e faces the outer oil passage groove 24f provided on the sleeve 24C. However, a circumferentially extending groove may also be provided on the outer peripheral surface of the sleeve 24C at a position facing the retainer oil passage hole 21e of the retainer 21C. The retainer oil passage hole 21e and the outer oil passage groove 24f may also communicate with each other through this groove.

[0065] In this configuration, the brush unit 20C forms an oil passage (as indicated by arrow Y3) connecting the frame 4 and the rotating shaft 2 via the holder oil passage hole 21e and the outer oil passage groove 24f. Additionally, a connecting oil passage 24g, connecting the outer circumferential surface of the sleeve 24C and the inner circumferential surface of the sleeve 24C, may be provided on the end face of the first opening H21a side of the holder 21C. The outer oil passage groove 24f may also be connected to the gap between the end portion of the first protrusion 21a and the outer circumferential surface of the brush 22 via the connecting oil passage 24g. Furthermore, the oil flow direction may be opposite to that indicated by arrow Y3. In the shaft conductive part 10, an oil passage hole is provided around the steel ball 12 to allow oil to flow from the brush unit 20C side into the interior of the rotating shaft 2. Thus, the brush unit 20C can also be used as an oil passage for supplying lubricating oil or other oils between the frame 4 and the rotating shaft 2.

[0066] (Fourth variation) Next, the fourth variation of the brush unit will be described. For example... Figure 10 As shown, in the fourth variation, the brush unit 20D replaces the electrode 25 of the above embodiment and has an electrode 25D with a different structure. The electrode 25D has an outer diameter larger than the outer diameter of the sleeve 24. The outer edge 25b of the electrode 25D is held by the retainer body 21c and the second extension 21b on the inner side of the corner K where the retainer body 21c and the second extension 21b are connected. In this embodiment, a conical surface 21h connected to the corner K is provided on the inner circumferential surface of the retainer body 21c. The outer edge 25b of the electrode 25D is held by the conical surface 21h and the second extension 21b of the retainer body 21c.

[0067] For example, electrode 25D can also be used as follows. Figure 2(b) As explained, by bending the end 21d of the retainer body portion 21c, the corner K is clamped by the second protrusion 21b and the retainer body portion 21c. In this case, the electrode 25D may also have a cylindrical portion along the inner circumferential surface of the end 21d of the retainer body portion 21c in the state before the outer edge portion 25b is clamped. This cylindrical portion of the electrode 25D may also be bent together with the end 21d when the second protrusion 21b is formed by bending the end 21d of the retainer body portion 21c. That is, the outer edge portion of the electrode 25D may also be in a state of double overlap of components.

[0068] Thus, in the brush unit 20D, the outer edge 25b of the electrode 25D is clamped by the second protrusion 21b and the holder body 21c, thereby enabling a more secure fixation of the electrode 25D relative to the holder 21. Therefore, in the brush unit 20D, the electrode 25D and the holder 21 can be electrically connected more stably.

[0069] (Fifth variation) Next, the fifth variation of the brush unit will be described. For example... Figure 11 As shown, the brush unit 20E of the fifth modification replaces the retainer 21 of the above embodiment with a retainer 21E having a different structure. The retainer 21E has a first protrusion 21a, a second protrusion 21j, and a retainer body 21c. The second protrusion 21j extends inward from the second opening H21b of the retainer body 21c. The second protrusion 21j extends from the second opening H21b and covers the entire second opening H21b. The electrode 25 is held by the second protrusion 21j and the sleeve 24.

[0070] In this case, the first extension 21a can also be used with Figure 2 (b) Similarly, the second protrusion 21b described herein is formed by bending the end of the cage body portion 21c. In this case, the first protrusion 21a is formed by bending in a manner that presses the sleeve 24 against the second protrusion 21j. Thus, the sleeve 24 and the electrode 25 are clamped by the first protrusion 21a and the second protrusion 21j. Even under these conditions, the brush unit 20E can ensure a stable conductive path with higher conductivity.

[0071] The embodiments of this disclosure have been described above, but this disclosure is not limited to the above embodiments.

[0072] A coil-shaped spring 23 is used as the force-applying part for the brush 22, etc., but other force-applying parts with different structures can be used if force can be applied to the brush 22, etc. The shaft conductive part 10 is not limited to having a steel ball 12. The shaft conductive part 10 can be any structure that can abut against the end face S of the brush 22 (for example, a structure with a protrusion). In addition, it is not limited to having a steel ball 12 in the shaft conductive part 10; a steel ball can also be installed at the end of the brush 22, and the steel ball abuts against the bottom surface of the recess of the shaft conductive part 10.

[0073] The connecting device 1 electrically connects the rotating shaft 2 to the frame 4, but it can also electrically connect a conductor other than the frame 4 to the rotating shaft 2. Parts of the structure of the above-described embodiments and variations can also be appropriately rearranged.

[0074] Explanation of reference numerals in the attached figures 1…Connecting device, 2…Rotating shaft, 4…Housing (conductor), 10…Shaft conductive part, 20, 20A~20E…Brush unit, 21, 21A~21C, 21E…Cage, 21a…First extension, 21b, 21j…Second extension, 21c…Cage body part, 21e…Cage oil passage hole, 21f…First oil passage hole, 21g…Second oil passage hole, 22…Brush, 23…Spring (force application part), 24, 24A~24C…Sleeve, 24a…Inner oil passage groove, 24b…Inlet oil passage hole, 24f…Outer oil passage groove, 24e…Sleeve oil passage hole, 25…Electrode, 26…Wiring, H21a…First opening, H21b…Second opening, K…Corner, R…Reception space.

Claims

1. A brush unit, mounted on a conductor, abutting against a shaft conductive portion disposed on a rotating shaft to electrically connect the conductor and the shaft conductive portion. The brush unit includes: A retainer, mounted on the conductor and having conductivity, has a receiving space on its inner side; The brush, housed within the housing space, abuts against the shaft conductive portion via a first opening provided in the holder, and is conductive; The force-applying part applies force to the brush towards the side where the first opening is located; A cylindrical sleeve is housed within the receiving space, and the brush is disposed on its inner side, and the brush is held so as to be able to slide in the direction of the force applied by the force-applying part to the brush; Electrodes are conductive; as well as Wiring connects the brush and the electrode. The cage has: The retainer body is provided in a manner that surrounds the sleeve and has a cylindrical structure that extends along the direction of force application of the force application part to the brush, with one end opening of the cylindrical structure serving as the first opening. as well as The second extension extends inward from the second opening on the side opposite to the first opening in the cage body. The second protrusion faces the end face of the sleeve on the side where the second opening is located in the direction in which the force-applying part applies force to the brush. The electrode is held by the second extension and the sleeve.

2. The brush unit according to claim 1, The cage also has a first extension portion that extends inward from the first opening in the cage body portion. The first protrusion faces the end face of the sleeve on the side where the first opening is located in the direction in which the force-applying part applies force to the brush. The sleeve and the electrode are held by the first extension and the second extension.

3. The brush unit according to claim 2, A first oil passage hole is provided in the first protrusion. A second oil passage hole is provided in the second extension portion. A sleeve oil passage hole is provided in the portion between the inner and outer circumferential surfaces of the sleeve, extending along the direction of the force applied to the brush by the force-applying part.

4. The brush unit according to claim 1, The cage body portion is provided with a cage oil passage hole that connects the outer peripheral surface and the inner peripheral surface of the cage body portion. An outer oil passage groove is provided on the outer peripheral surface of the sleeve, extending along the direction of the force applied to the brush by the force-applying part.

5. The brush unit according to claim 1, The cage body portion is provided with a cage oil passage hole that connects the outer peripheral surface and the inner peripheral surface of the cage body portion. An inner oil passage groove is provided on the inner circumferential surface of the sleeve, extending along the direction of the force applied to the brush by the force-applying part. The sleeve is also provided with an oil inlet hole that connects the outer circumferential surface of the sleeve and the inner oil passage groove.

6. The brush unit according to claim 1, The electrode is elastically deformable in the clamping direction of the second extension and the sleeve, and is clamped by the second extension and the sleeve in a compressed state.

7. The brush unit according to claim 1, The outer edge of the electrode is held by the cage body and the second extension at the corner where the cage body and the second extension meet.

8. A connecting device for electrically connecting a rotating shaft and a conductor, The connecting device includes: A conductive part is mounted on the end of the rotating shaft and has electrical conductivity; and The brush unit according to any one of claims 1 to 7, wherein one end of the brush unit abuts against the shaft conductive portion, and the other end is mounted on the conductor, thereby electrically connecting the shaft conductive portion to the conductor.

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