Brush unit and connecting device
The brush unit with a holder, brush, sleeve, and electrode configuration provides a stable conductive path and oil passage, addressing electric corrosion and improving electrical connectivity between a rotating shaft and conductor.
Patent Information
- Application Number
- JP2023220971
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-12-27
- Publication Date
- 2025-07-09
AI Technical Summary
Existing brush units do not provide a stable and conductive path for electrically connecting a rotating shaft to a conductor, leading to potential electric corrosion in bearings.
A brush unit comprising a holder with a brush that abuts against a shaft conductive part, a biasing part to maintain contact, a sleeve to hold the brush slidably, an electrode, and wiring to connect the brush and electrode, with protruding portions ensuring stable electrical connection and oil passage functionality.
Secures a stable conductive path with higher conductivity and facilitates oil passage between the conductor and rotating shaft, preventing electric corrosion and enhancing electrical connectivity.
Smart Images
Figure 2025103526000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a brush unit for electrically connecting a rotating shaft and a conductor, and a connecting device.
Background Art
[0002] A rotating shaft driven by an electric motor may be charged. When the charge charged on this rotating shaft flows as an electric current to the bearing that supports the rotating shaft, electric corrosion may occur in the bearing. In order to prevent an electric current from flowing through the bearing, for example, Patent Document 1 describes that a brush unit is brought into contact with an end portion of a rotating shaft, and the charge charged on the rotating shaft is caused to flow to a conductor such as a housing through the brush unit.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] Patent Document 1 does not describe the details of the configuration of the brush unit that allows an electric current to flow from the rotating shaft to the conductor. For this reason, in this technical field, there is a need for a brush unit capable of ensuring a stable conductive path having higher conductivity, and a connecting device including this brush unit.
Means for Solving the Problems
[0005] The brush unit according to the present invention is "[1] a brush unit that is attached to a conductor and abuts against a shaft conductive part provided on a rotating shaft to electrically connect the conductor and the shaft conductive part, and is attached to the conductor and has conductivity, and a holder provided with a housing space inside, a brush having conductivity, which is housed in the housing space and abuts against the shaft conductive part through a first opening provided in the holder, a biasing part that biases the brush toward the first opening side, a cylindrical sleeve that is housed in the housing space, has the brush disposed inside, and holds the brush slidably in the biasing direction of the brush by the biasing part, an electrode having conductivity, and a wiring that connects the brush and the electrode, wherein the holder is provided so as to surround the sleeve and has a cylindrical shape extending in the biasing direction of the brush by the biasing part, and includes a holder main body part having one end opening of the cylinder as the first opening, and a second protruding part that protrudes inward from a second opening on the opposite side of the first opening in the holder main body part, the second protruding part faces an end surface on the second opening side of the sleeve in the biasing direction of the brush by the biasing part, and the electrode is sandwiched between the second protruding part and the sleeve."
[0006] In this brush unit, a holder attached to a conductor and a brush that abuts against a shaft conductive part attached to a rotating shaft are electrically connected to each other via wiring and an electrode. Further, the electrode is sandwiched between a second protruding part of the holder and the sleeve. Thereby, the electrode and the holder are stably electrically connected to each other. Thus, the brush unit can secure a stable conductive path having higher conductivity.
[0007] The brush unit according to the present invention may be "[2] The holder further has a first protruding portion that protrudes inward from the first opening in the holder main body portion, and the first protruding portion faces the end surface on the first opening side of the sleeve in the biasing direction of the brush by the biasing portion, and the sleeve and the electrode are sandwiched between the first protruding portion and the second protruding portion, the brush unit according to [1] above." In this case, the electrode is more securely electrically connected to the holder by being sandwiched between the first protruding portion and the second protruding portion together with the sleeve.
[0008] The brush unit according to the present invention may be "[3] The first protruding portion is provided with a first oil passage hole, the second protruding portion is provided with a second oil passage hole, and a sleeve oil passage hole extending in the biasing direction of the brush by the biasing portion is provided in a portion between the inner peripheral surface and the outer peripheral surface of the sleeve, the brush unit according to [2] above." In this case, in the brush unit, an oil passage connecting the conductor and the rotating shaft side is formed by 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 flowing oil such as lubricating oil between the conductor and the rotating shaft.
[0009] The brush unit according to the present invention may be "[4] The holder main body portion is provided with a holder oil passage hole connecting the outer peripheral surface and the inner peripheral surface of the holder main body portion, and an outer oil passage groove extending in the biasing direction of the brush by the biasing portion is provided on the outer peripheral surface of the sleeve, the brush unit according to [1] above." In this case, in the brush unit, an oil passage connecting the conductor and the rotating shaft side is formed by the holder oil passage hole and the outer oil passage groove. Note that at the end portion on the first opening side of the holder, oil passes through the gap portion between the outer peripheral surface of the brush and the holder. Thus, the brush unit can also be used as an oil passage for flowing oil such as lubricating oil between the conductor and the rotating shaft.
[0010] The brush unit according to the present invention may be "[5] In the holder main body portion, a holder oil passage hole connecting the outer peripheral surface and the inner peripheral surface of the holder main body portion is provided, and on the inner peripheral surface of the sleeve, an inner oil passage groove extending in the biasing direction of the brush by the biasing portion is provided. Further, in the sleeve, an introduction oil passage hole connecting the outer peripheral surface of the sleeve and the inner oil passage groove is provided, the brush unit according to [1] above." In this case, in the brush unit, an oil passage connecting the conductor and the rotating shaft side is formed by the holder oil passage hole, the introduction oil passage hole, and the inner oil passage groove. Note that at the end portion on the side of the first opening in the holder, oil passes through the gap between the outer peripheral surface of the brush and the holder. Thus, the brush unit can also be used as an oil passage for flowing oil such as lubricating oil between the conductor and the rotating shaft.
[0011] The brush unit according to the present invention may be "[6] The electrode is elastically deformable in the sandwiching direction between the second protruding portion and the sleeve, and is sandwiched in a compressed state by the second protruding portion and the sleeve, the brush unit according to any one of [1] to [5] above." In this case, the electrode biases the second protruding portion of the holder by the force with which the electrode tries to return to its original shape. Thereby, in the brush unit, the contact property between the electrode and the holder is improved, and the electrode and the second protruding portion of the holder can be more stably electrically connected.
[0012] The brush unit according to the present invention may be "[7] The outer edge portion of the electrode is sandwiched between the holder main body portion and the second protruding portion at the corner where the holder main body portion and the second protruding portion are connected to each other, the brush unit according to any one of [1] to [6] above." Thereby, in the brush unit, the electrode can be fixed more firmly by sandwiching the outer edge portion of the electrode. Therefore, in the brush unit, the electrode and the holder can be more stably electrically connected.
[0013] The connecting device according to the present invention is "[8] A connecting device for electrically connecting a rotating shaft and a conductor, comprising a shaft conductive part that is attached to the end of the rotating shaft and has conductivity, and one end of which abuts against the shaft conductive part, and the other end of which is attached to the conductor, and the brush unit according to any one of the above [1] to [7], which electrically connects the shaft conductive part and the conductor."
[0014] This connecting device is provided with the above-described brush unit. Therefore, the connecting device can secure a stable conductive path having higher conductivity as described above.
Effects of the Invention
[0015] According to the present invention, a stable conductive path having higher conductivity can be secured.
Brief Description of the Drawings
[0016]
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Figure 11
[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each figure, the same or corresponding elements are denoted by the same reference numerals, and redundant descriptions are omitted.
[0018] As shown in FIG. 1, a connecting device 1 electrically connects a rotating shaft 2 rotatably supported by a bearing 3 and a housing (conductor) 4. The rotating shaft 2 may be the shaft of an electric motor, or may be a shaft connected to the shaft of an electric motor via a gear. In the present embodiment, the portion on the end 2a side of the rotating shaft 2 has a hollow shaft (hollow structure). Note that the rotating shaft 2 may be a hollow shaft not only at the portion of the end 2a but also as a whole. The bearing 3 supports the rotating shaft 2 rotatably about the rotation axis L. The type of the bearing 3 is not particularly limited as long as it can support the rotating shaft 2 rotatably.
[0019] The housing 4 houses the connecting device 1, the rotating shaft 2, the bearing 3, and the like. The housing 4 has conductivity. In the present embodiment, the connecting device 1 forms a conductive path having a lower resistance value than the conductive path from the rotating shaft 2 to the housing 4 via the bearing 3 by electrically connecting the rotating shaft 2 and the housing 4.
[0020] As shown in FIG. 1, the connecting device 1 includes a shaft conductive portion 10 and a brush unit 20. The shaft conductive portion 10 has conductivity. Further, the shaft conductive portion 10 has a shape having a recess 10a. The shaft conductive portion 10 is attached to the end 2a of the rotating shaft 2 such that the opening 10b of the recess 10a faces outward.
[0021] More specifically, the shaft conductive part 10 includes a ball holder 11 and steel balls 12. The ball holder 11 and the steel balls 12 each have conductivity. The ball holder 11 has a shape with a recess 10a. The ball holder 11 is formed, for example, by pressing a steel plate.
[0022] The steel balls 12 may be, for example, balls used in bearings. The steel balls 12 are attached to the bottom 10c of the recess 10a of the ball holder 11. Here, as an example, the steel balls 12 are fitted into holes provided in the bottom 10c of the recess 10a of the ball holder 11 and fixed by caulking. In this way, the steel balls 12 are provided at the bottom 10c of the recess 10a in the shaft conductive part 10 and constitute a convex contact part that contacts the brush unit 20 (the end face S of the brush 22). The steel balls 12 are attached to the ball holder 11 so that the centers of the steel balls 12 are located on the rotation axis line L whose rotation center is the rotation center of the rotation shaft 2.
[0023] On the outer peripheral surface of the ball holder 11, there is provided a fitting part 11a that is fitted into and fixed to the inner peripheral surface 2b of the end part 2a of the rotation shaft 2. The ball holder 11 is fitted into and fixed to the inner peripheral surface 2b of the end part 2a of the rotation shaft 2 so that the opening 10b of the recess 10a faces outward. The fitting part 11a of the ball holder 11 and the inner peripheral surface 2b of the rotation shaft 2 are engaged with each other. For this reason, the ball holder 11 rotates integrally with the rotation shaft 2. The steel balls 12 contact one end part (the end face S of the brush 22) of the brush unit 20 within the recess 10a of the ball holder 11.
[0024] One end part of the brush unit 20 is inserted into the recess 10a of the shaft conductive part 10 and brought into contact with the steel balls 12 provided at the bottom 10c of the recess 10a. Also, the other end part of the brush unit 20 is attached to the housing 4. The brush unit 20 electrically connects the shaft conductive part 10 attached to the rotation shaft 2 and the housing 4. More specifically, as shown in FIGS. 2(a) and 3, the brush unit 20 includes a holder 21, a brush 22, a spring (biasing part) 23, a sleeve 24, an electrode 25, and a wiring 26.
[0025] The holder 21 has conductivity. As an example of the material of the holder 21, a conductive metal (steel) can be used. An accommodation space R is provided inside the holder 21. The holder 21 is provided with a first opening H21a. The end portion of the holder 21 on the side where the first opening H21a is provided is inserted into the recess 10a of the shaft conductive portion 10. The other end portion of the holder 21 is attached to the housing 4. In the present embodiment, the housing 4 is provided with a recess 4a (see FIG. 1) on the rotation axis line L that is the rotation center of the rotation shaft 2. The holder 21 is attached to the housing 4 by fitting the other end portion into the recess 4a. Thereby, the housing 4 and the holder 21 are electrically connected to each other.
[0026] The brush 22 is accommodated in the accommodation space R of the holder 21. The brush 22 has conductivity. The brush 22 can slide along the rotation axis line L inside the holder 21. As an example of the brush 22, a carbon brush can be used. In the present embodiment, the brush 22 has a columnar shape with the rotation axis line L as the axis. However, the brush 22 is not limited to the columnar shape and may have a prismatic shape such as a quadrangle. By making the shape of the brush 22 columnar, the brush 22 can be easily formed.
[0027] The brush 22 abuts on the shaft conductive portion 10 through the first opening H21a provided in the holder 21. More specifically, the end face S on the bottom 10c side (the steel ball 12 side) of the recess 10a of the shaft conductive portion 10 in the brush 22 abuts on the steel ball 12. That is, the end face S becomes a contact face that abuts on the steel ball 12. The shape of the end face S may be flat, concave (for example, a shape that is recessed in an arc shape), or convex (for example, a shape that protrudes in an arc shape). In the present embodiment, it is sufficient that the end face S can be in point contact with the steel ball 12.
[0028] As described above, the steel ball 12 is provided such that the center of the steel ball 12 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. As a result, even when the shaft conductive part 10 rotates together with the rotation shaft 2, the contact point between the end face S of the brush 22 and the steel ball 12 does not shift in position. That is, at the connection portion between the end face S and the steel ball 12, the difference in peripheral speed between the two becomes zero.
[0029] The spring 23 is accommodated in the accommodation space R. The spring 23 has conductivity. The spring 23 is, as an example, a coil-shaped compression spring. The spring 23 biases the brush 22 toward the first opening H21a side of the holder 21. That is, the spring 23 biases the brush 22 in the direction in which the brush 22 approaches the steel ball 12. As a result, the brush 22 is in point contact with the steel ball 12 in a state where the connection device 1 is attached. That is, the brush 22 and the steel ball 12 are electrically connected.
[0030] The sleeve 24 is accommodated in the accommodation space R. The material of the sleeve 24 may be a resin or a metal having conductivity. The sleeve 24 has a cylindrical shape. In the present embodiment, the sleeve 24 has a cylindrical shape. Inside the sleeve 24, the brush 22 and the spring 23 are arranged. The sleeve 24 extends in the biasing direction of the brush 22 by the spring 23. The sleeve 24 slidably holds the brush 22 in the biasing direction of the brush 22 by the spring 23.
[0031] Here, the holder 21 has a first overhanging portion 21a, a second overhanging portion 21b, and a holder main body portion 21c. The holder main body portion 21c is provided so as to surround the sleeve 24. The holder main body portion 21c has a cylindrical shape extending in the biasing direction of the brush 22 by the spring 23. In the present embodiment, the holder main body portion 21c has a cylindrical shape. That is, the sleeve 24 is arranged inside the holder main body portion 21c. One end opening of the cylindrical shape in the holder main body portion 21c becomes the first opening H21a. In the holder main body portion 21c, the end opening on the side opposite to the first opening H21a becomes the second opening H21b.
[0032] The first protruding portion 21a protrudes inward from the first opening H21a of the holder main body portion 21c. A predetermined gap is provided between the tip portion of the first protruding portion 21a in the protruding direction and the outer peripheral surface of the brush 22. The first protruding portion 21a faces the end surface on the first opening H21a side of the sleeve 24 in the biasing direction of the brush 22 by the spring 23.
[0033] The second protruding portion 21b protrudes inward from the second opening H21b of the holder main body portion 21c. The second protruding portion 21b faces the end surface on the second opening H21b side of the sleeve 24 in the biasing direction of the brush 22 by the spring 23.
[0034] The electrode 25 has conductivity. The electrode 25 is housed in the housing space R and is in contact with the second protruding portion 21b. The electrode 25 has a convex portion 25a that protrudes toward the brush 22. The spring 23 is disposed between the electrode 25 and the brush 22. The end portion of the spring 23 is fitted outside the convex portion 25a. The convex portion 25a can position the spring 23.
[0035] The electrode 25 has an outer shape larger than the hole inside the sleeve 24. The outer edge portion of the electrode 25 is sandwiched between the second protruding portion 21b of the holder 21 and the sleeve 24 in the biasing direction of the brush 22 by the spring 23. In the present embodiment, the sleeve 24 and the electrode 25 are sandwiched between the first protruding portion 21a and the second protruding portion 21b of the holder 21 in the biasing direction of the brush 22 by the spring 23.
[0036] One end of the wiring 26 is connected to the electrode 25. The other end of the wiring 26 is connected to the brush 22. The wiring 26 electrically connects the electrode 25 and the brush 22. The wiring 26 has flexibility, for example. The wiring 26 maintains the state in which the electrode 25 and the brush 22 are electrically connected even when the distance between the electrode 25 and the brush 22 changes.
[0037] The wiring 26 is passed through the inside of the coil-shaped spring 23. When both ends of the wiring 26 are connected to the electrode 25 and the brush 22 respectively, the brush 22, the spring 23, the electrode 25, and the wiring 26 are integrated with each other. Thereby, the brush unit 20 can improve the assemblability when assembling the brush 22, the spring 23, the electrode 25, and the wiring 26 to the holder 21.
[0038] The brush 22 is connected to the electrode 25 by the wiring 26. The electrode 25 is fixed to the holder 21 by being sandwiched between the second protruding portion 21b and the sleeve 24. Thereby, in a state where the steel ball 12 is not in contact with the brush 22 (for example, when assembling the brush unit 20 to the housing 4, and the state before assembling the brush unit 20, etc.), the brush 22 does not fall off from the holder 21.
[0039] In addition, as shown in FIG. 2(b), the second protruding portion 21b may be formed by performing a bending process (for example, hot curl process) on the end portion 21d (the portion that becomes the second protruding portion 21b) of the holder main body portion 21c in a state where each component is accommodated in the accommodation space R of the holder 21.
[0040] Also, the electrode 25 is configured to be elastically deformable in the sandwiching direction between the second protruding portion 21b and the sleeve 24. The electrode 25 is sandwiched in a compressed state by the second protruding portion 21b and the sleeve 24. For example, the state shown in FIG. 2(b) is a state where the electrode 25 is not sandwiched by the second protruding portion 21b and the sleeve 24. As an example of a configuration that is elastically deformable in the sandwiching direction, as shown in FIG. 2(b), the portion of the electrode 25 sandwiched by the second protruding portion 21b and the sleeve 24 may be inclined or curved with respect to the end face of the sleeve 24. When the second protruding portion 21b is formed by bending, the electrode 25 is compressed by pressing the inclined or curved portion of the electrode 25 against the end face of the sleeve 24, and the electrode 25 is sandwiched by the sleeve 24.
[0041] In this embodiment, the second protruding portion 21b extends over the entire circumferential direction of the end portion of the holder main body portion 21c. That is, the second protruding portion 21b has an annular shape. However, it is not limited thereto, and one or more second protruding portions 21b may be provided intermittently along the circumferential direction of the second opening H21b of the holder main body portion 21c. Similarly, the first protruding portion 21a is not limited to having an annular shape. One or more first protruding portions 21a may be provided intermittently along the circumferential direction of the first opening H21a of the holder main body portion 21c.
[0042] Next, the conductive path between the rotating shaft 2 and the housing 4 when the connecting device 1 is used will be described. In this embodiment, the ball holder 11, the steel ball 12, the holder 21, the brush 22, the electrode 25, and the wiring 26 have conductivity. Therefore, the rotating shaft 2 is electrically connected to the housing 4 via the ball holder 11, the steel ball 12, the brush 22, the wiring 26, the electrode 25, and the holder 21. That is, the ball holder 11, the steel ball 12, the brush 22, the wiring 26, the electrode 25, and the holder 21 form a conductive path that electrically connects the rotating shaft 2 and the housing 4. Further, in this embodiment, the spring 23 has conductivity. Therefore, the spring 23 can also serve as a conductive path between the brush 22 and the electrode 25. Thereby, even when the rotating shaft 2 is in a rotating state, the rotating shaft 2 and the housing 4 are electrically connected.
[0043] As described above, in this brush unit 20, the holder 21 attached to the housing 4 and the brush 22 that contacts the shaft conductive portion 10 attached to the rotating shaft 2 are electrically connected to each other via the wiring 26 and the electrode 25. Further, the electrode 25 is sandwiched between the second protruding portion 21b of the holder 21 and the sleeve 24. Thereby, the electrode 25 and the wiring 26 are stably electrically connected to each other. In this way, the brush unit 20 and the connecting device 1 including this brush unit 20 can secure a stable conductive path having higher conductivity.
[0044] The holder 21 has a first projecting portion 21a that projects inward from the first opening H21a in the holder main body portion 21c, and a second projecting portion 21b that projects inward from the second opening H21b in the holder main body portion 21c. The sleeve 24 and the electrode 25 are sandwiched between the first projecting portion 21a and the second projecting portion 21b. In this case, the electrode 25 is more reliably electrically connected to the sleeve 24 by being sandwiched together with the sleeve 24 between the first projecting portion 21a and the second projecting portion 21b.
[0045] The electrode 25 is sandwiched in a compressed state between the second projecting portion 21b and the sleeve 24. In this case, the electrode 25 biases the second projecting portion 21b of the holder 21 by the force with which the electrode 25 tries to return to its original shape. As a result, in the brush unit 20, the contact property between the electrode 25 and the second projecting portion 21b of the holder 21 is improved, and the electrode 25 and the second projecting portion 21b can be more stably electrically connected.
[0046] (First Modified Example) Next, a first modified example of the brush unit will be described. As shown in FIGS. 4 and 5, the brush unit 20A according to the first modified example includes a holder 21A and a sleeve 24A having different configurations instead of the holder 21 and the sleeve 24 according to the above embodiment. A holder oil passage hole 21e that connects the outer peripheral surface and the inner peripheral surface of the holder main body portion 21c is provided in the holder main body portion 21c of the holder 21A. An oil passage is provided in the housing 4. The oil passage provided in the housing 4 opens to the wall surface of the recess 4a into which the brush unit 20A is fitted. The holder oil passage hole 21e provided in the holder 21A communicates with the oil passage provided in the housing 4.
[0047] On the inner peripheral surface of the sleeve 24A, an inner oil passage groove 24a is provided. The inner oil passage groove 24a extends in the biasing direction of the brush 22 by the spring 23. In the present embodiment, a plurality of inner oil passage grooves 24a are provided on the inner peripheral surface of the sleeve 24A. Further, the sleeve 24A is provided with an introduction oil passage hole 24b that connects the outer peripheral surface of the sleeve 24 and the inner oil passage groove 24a. The introduction oil passage hole 24b is provided at a position facing the holder oil passage hole 21e in a direction orthogonal to the biasing direction of the brush 22 in the spring 23. Further, on the outer peripheral surface of the sleeve 24, an oil passage groove 24c extending in the circumferential direction is provided at a position where the introduction oil passage hole 24b opens. Thereby, even if the introduction oil passage hole 24b does not face the holder oil passage hole 21e provided in the holder 21, it can communicate with the holder oil passage hole 21e via the oil passage groove 24c.
[0048] Note that the protruding length of the first protruding portion 21a from the holder main body portion 21c is set so that oil flowing through the inner oil passage groove 24a can pass between the tip of the first protruding portion 21a and the outer peripheral surface of the brush 22.
[0049] In this case, in the brush unit 20A, an oil passage indicated by an arrow Y1 connecting the housing 4 and the rotating shaft 2 side is formed by the holder oil passage hole 21e, the introduction oil passage hole 24b, and the inner oil passage groove 24a. Note that 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 21 (the tip of the first protruding portion 21a). Further, the flow direction of the oil may be opposite to the direction indicated by the arrow Y1. The shaft conductive portion 10 only needs to be provided with an oil passage hole around the steel ball 12 so that oil can flow from the brush unit 20A side into the inside of the rotating shaft 2. Thus, the brush unit 20A can also be used as an oil passage for flowing oil such as lubricating oil between the housing 4 and the rotating shaft 2.
[0050] (Second Modification Example) Next, a second modified example of the brush unit will be described. As shown in FIGS. 6 and 7, the brush unit 20B according to the second modified example includes a holder 21B and a sleeve 24B having different configurations instead of the holder 21 and the sleeve 24 according to the above embodiment. A first oil passage hole 21f is provided in the first protruding portion 21a of the holder 21B. In the present embodiment, a plurality of first oil passage holes 21f are provided in the first protruding portion 21a. A second oil passage hole 21g is provided in the second protruding portion 21b of the holder 21B. In the present embodiment, a plurality of second oil passage holes 21g are provided in the second protruding portion 21b. Note that an oil passage is provided in the housing 4. The oil passage provided in the housing 4 opens to the wall surface of the recess 4a into which the brush unit 20B is fitted. The second oil passage hole 21g provided in the holder 21B communicates with the oil passage provided in the housing 4.
[0051] In the sleeve 24B, a sleeve oil passage hole 24e extending in the biasing direction of the brush 22 by the spring 23 is provided in a portion between the inner peripheral surface and the outer peripheral surface of the sleeve 24B. In the present embodiment, a plurality of sleeve oil passage holes 24e are provided around the central hole (the hole for accommodating the brush 22 or the like) of the cylindrical sleeve 24. The sleeve oil passage hole 24e penetrates the sleeve 24B in the biasing direction of the brush 22 in the spring 23. Note that the electrode 25 has a size that does not block the sleeve oil passage hole 24e provided in the sleeve 24B.
[0052] The second oil passage hole 21g provided in the second protruding portion 21b of the holder 21B and the sleeve oil passage hole 24e provided in the sleeve 24B communicate with each other. The first oil passage hole 21f provided in the first protruding portion 21a of the holder 21B and the sleeve oil passage hole 24e provided in the sleeve 24B communicate with each other. The sleeve 24B is accommodated in the accommodation space R such that the second oil passage hole 21g and the sleeve oil passage hole 24e communicate with each other, and the first oil passage hole 21f and the sleeve oil passage hole 24e communicate with each other. However, in the sleeve 24B, a groove extending in the circumferential direction may be provided on the end face facing the second protruding portion 21b. Through this groove, the second oil passage hole 21g and the sleeve oil passage hole 24e may communicate with each other. Similarly, in the sleeve 24B, a groove extending in the circumferential direction may be provided on the end face facing the first protruding portion 21a. Through this groove, the first oil passage hole 21f and the sleeve oil passage hole 24e may communicate with each other.
[0053] In this case, the brush unit 20B forms an oil passage indicated by the arrow Y2 that connects the housing 4 and the rotating shaft 2 side through the second oil passage hole 21g, the sleeve oil passage hole 24e, and the first oil passage hole 21f. Also, the flow direction of the oil may be opposite to the direction indicated by the arrow Y2. In the shaft conductive portion 10, oil passage holes may be provided around the steel ball 12 so that oil can flow from the brush unit 20B side into the inside of the rotating shaft 2. Thus, the brush unit 20B can also be used as an oil passage for flowing oil such as lubricating oil between the housing 4 and the rotating shaft 2.
[0054] (Third Modification Example) Next, a third modification example of the brush unit will be described. As shown in FIGS. 8 and 9, the brush unit 20C according to the third modification example includes a holder 21C and a sleeve 24C having different configurations instead of the holder 21 and the sleeve 24 according to the above-described embodiment. A holder oil passage hole 21e that connects the outer peripheral surface and the inner peripheral surface of the holder main body portion 21c is provided in the holder main body portion 21c of the holder 21C. The brush unit 20C according to this modification example has the same configuration as the brush unit 20A according to the first modification example. An oil passage is provided in the housing 4. The oil passage provided in the housing 4 opens to the wall surface of the recess 4a into which the brush unit 20C is fitted. The holder oil passage hole 21e provided in the holder 21C communicates with the oil passage provided in the housing 4.
[0055] An outer oil passage groove 24f is provided on the outer peripheral surface of the sleeve 24C. The outer oil passage groove 24f extends in the biasing direction of the brush 22 by the spring 23. In the present embodiment, a plurality of outer oil passage grooves 24f are provided on the outer peripheral surface of the sleeve 24A. The holder oil passage hole 21e faces the outer oil passage groove 24f provided in the sleeve 24C. However, a groove extending in the circumferential direction may be provided at a position on the outer peripheral surface of the sleeve 24C that faces the holder oil passage hole 21e of the holder 21C. The holder oil passage hole 21e and the outer oil passage groove 24f may communicate with each other through this groove.
[0056] In this case, in the brush unit 20C, an oil passage indicated by an arrow Y3 that connects the housing 4 and the rotating shaft 2 side is formed by the holder oil passage hole 21e and the outer oil passage groove 24f. Note that a connecting oil passage 24g that connects the outer peripheral surface and the inner peripheral surface of the sleeve 24C may be provided on the end surface on the side of the first opening H21a in the holder 21C. The outer oil passage groove 24f may be connected to the gap between the tip of the first overhanging portion 21a and the outer peripheral surface of the brush 22 via the connecting oil passage 24g. Also, the flow direction of the oil may be opposite to the direction indicated by the arrow Y3. For the shaft conductive portion 10, it is sufficient that an oil passage hole is provided around the steel ball 12 so that oil can flow from the brush unit 20C side into the inside of the rotating shaft 2. Thus, the brush unit 20C can also be used as an oil passage for flowing oil such as lubricating oil between the housing 4 and the rotating shaft 2.
[0057] (Fourth Modified Example) Next, a fourth modified example of the brush unit will be described. As shown in FIG. 10, the brush unit 20D according to the fourth modified example includes an electrode 25D having a different configuration instead of the electrode 25 according to the above embodiment. The electrode 25D has an outer diameter larger than the outer diameter of the sleeve 24. The outer edge portion 25b of the electrode 25D is sandwiched between the holder main body portion 21c and the second overhanging portion 21b inside the corner K where the holder main body portion 21c and the second overhanging portion 21b are connected to each other. In the present embodiment, a tapered surface 21h connected to the corner K is provided on the inner peripheral surface of the holder main body portion 21c. The outer edge portion 25b of the electrode 25D is sandwiched between the tapered surface 21h of the holder main body portion 21c and the second overhanging portion 21b.
[0058] For example, as described with reference to FIG. 2(b), the electrode 25D may be bent at the end 21d of the holder main body 21c so as to be sandwiched between the second protruding portion 21b and the holder main body 21c at the corner K. In this case, before the outer edge portion 25b is sandwiched, the electrode 25D may have a cylindrical portion along the inner peripheral surface of the end 21d of the holder main body 21c at the outer edge portion of the electrode 25D. When the second protruding portion 21b is formed by bending the end 21d of the holder main body 21c, the cylindrical portion of the electrode 25D may be folded together with the end 21d. That is, the outer edge portion of the electrode 25D may be in a state where the members are overlapped doubly.
[0059] As described above, in the brush unit 20D, by sandwiching the outer edge portion 25b of the electrode 25D between the second protruding portion 21b and the holder main body 21c, the electrode 25D can be more firmly fixed to the holder 21. Therefore, in the brush unit 20D, the electrode 25D and the holder 21 can be more stably and electrically connected.
[0060] (Fifth Modification Example) Next, a fifth modification example of the brush unit will be described. As shown in FIG. 11, the brush unit 20E according to the fifth modification example includes a holder 21E having a different configuration instead of the holder 21 according to the above-described embodiment. The holder 21E has a first protruding portion 21a, a second protruding portion 21j, and a holder main body 21c. The second protruding portion 21j protrudes inward from the second opening H21b of the holder main body 21c. The second protruding portion 21j protrudes from the second opening H21b and covers the entire second opening H21b. The electrode 25 is sandwiched between the second protruding portion 21j and the sleeve 24.
[0061] In this case, the first protruding portion 21a may be formed by bending the end portion of the holder main body portion 21c in the same manner as the second protruding portion 21b described with reference to FIG. 2(b). At that time, the first protruding portion 21a is formed by bending so as to press the sleeve 24 against the second protruding portion 21j side. Thereby, the sleeve 24 and the electrode 25 are sandwiched between the first protruding portion 21a and the second protruding portion 21j. Even in this case, the brush unit 20E can secure a stable conductive path having higher conductivity.
[0062] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above embodiments.
[0063] Although the coil-shaped spring 23 is used as the biasing portion for biasing the brush 22 and the like, other configurations of the biasing portion may be used as long as the brush 22 and the like can be biased. The shaft conductive portion 10 is not limited to including the steel balls 12. The shaft conductive portion 10 may have a configuration (for example, a configuration having a convex portion) that can contact the end surface S of the brush 22. Further, the shaft conductive portion 10 is not limited to being provided with the steel balls 12, and the steel balls may be attached to the tip of the brush 22, and these steel balls may be in contact with the bottom surface of the concave portion of the shaft conductive portion 10.
[0064] The connecting device 1 electrically connects the rotating shaft 2 and the housing 4, but the rotating shaft 2 may be electrically connected to a conductor other than the housing 4. A part of the configurations of the above-described embodiments and each modification may be appropriately recombined.
Explanation of Reference Numerals
[0065] 1... Connecting device, 2... Rotating shaft, 4... Housing (conductor), 10... Shaft conductive part, 20, 20A to 20E... Brush unit, 21, 21A to 21C, 21E... Holder, 21a... First protruding part, 21b, 21j... Second protruding part, 21c... Holder main body part, 21e... Holder oil passage hole, 21f... First oil passage hole, 21g... Second oil passage hole, 22... Brush, 23... Spring (biasing part), 24, 24A to 24C... Sleeve, 24a... Inner oil passage groove, 24b... Introduction 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 part, R... Accommodation space.
Claims
1. A brush unit that is attached to a conductor and abuts against a shaft conductive portion provided on a rotating shaft to electrically connect the conductor and the shaft conductive portion, a holder that is attached to the conductor and has conductivity, and has an accommodation space provided inside; a brush having conductivity, which is accommodated in the accommodation space and abuts against the shaft conductive portion through a first opening provided in the holder; a biasing portion that biases the brush toward the first opening side; a cylindrical sleeve that is accommodated in the accommodation space, has the brush disposed inside, and slidably holds the brush in the biasing direction of the brush by the biasing portion; an electrode having conductivity; a wiring that connects the brush and the electrode; comprising: The holder: a holder main body portion that is provided so as to surround the sleeve and has a cylindrical shape extending in the biasing direction of the brush by the biasing portion, and has one end opening of the cylindrical shape as the first opening; a second protruding portion that protrudes inward from a second opening on the opposite side of the first opening in the holder main body portion; having: The second protruding portion faces the end face on the second opening side of the sleeve in the biasing direction of the brush by the biasing portion. The electrode is sandwiched between the second protruding portion and the sleeve. A brush unit.
2. The holder further has a first protruding portion that protrudes inward from the first opening in the holder main body portion, The first protruding portion faces the end face on the first opening side of the sleeve in the biasing direction of the brush by the biasing portion, The sleeve and the electrode are sandwiched between the first protruding portion and the second protruding portion. The brush unit according to Claim 1.
3. A first oil passage hole is provided in the first protruding portion, A second oil passage hole is provided in the second protruding portion, An oil passage hole of the sleeve extending in the biasing direction of the brush by the biasing portion is provided in a portion between the inner peripheral surface and the outer peripheral surface of the sleeve. The brush unit according to Claim 2.
4. A holder oil passage hole connecting the outer peripheral surface and the inner peripheral surface of the holder main body portion is provided in the holder main body portion, An outer oil groove extending in the biasing direction of the brush by the biasing portion is provided on the outer peripheral surface of the sleeve. The brush unit according to Claim 1.
5. The holder main body portion is provided with a holder oil passage hole that connects the outer peripheral surface and the inner peripheral surface of the holder main body portion. The inner peripheral surface of the sleeve is provided with an inner oil passage groove that extends in the biasing direction of the brush by the biasing portion. Furthermore, the sleeve is provided with an introduction oil passage hole that connects the outer peripheral surface of the sleeve and the inner oil passage groove. The brush unit according to claim 1.
6. The electrode is elastically deformable in the clamping direction between the second protruding portion and the sleeve, and is clamped in a compressed state by the second protruding portion and the sleeve. The brush unit according to claim 1.
7. The outer edge portion of the electrode is clamped by the holder main body portion and the second protruding portion at the corner where the holder main body portion and the second protruding portion are connected to each other. The brush unit according to claim 1.
8. A connecting device that electrically connects a rotating shaft and a conductor, A shaft conductive portion that is attached to the end of the rotating shaft and has conductivity, One end abuts against the shaft conductive portion, and the other end is attached to the conductor. The brush unit according to any one of claims 1 to 7 that electrically connects the shaft conductive portion and the conductor. A connecting device comprising.
Citation Information
Patent Citations
Thin film transistor
JP1987042566A
Cited By
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Brush unit
WO2026121262A1