Power supply unit and bearing unit

Abstract

The energizing unit (1) is configured to have: an annular outer shell body (2) having a circumferential groove with an opening toward the inner diameter side and having conductivity; an energizing member (3) disposed in the circumferential groove and protruding radially inward from the outer shell body (2) and having conductivity; and a radial elastic member (4) disposed in the circumferential groove and applying force radially inward to the energizing member (3).

Description

Technical Field

[0001] The present invention relates to an energizing unit arranged in parallel with a bearing supporting a rotating shaft such as a motor shaft, and a bearing unit employing the energizing unit. Background Technology

[0002] Bearings that support rotating shafts such as motor shafts are typically rolling bearings, especially ball bearings. In recent years, inverter control has been commonly used to enable efficient motor operation. Especially in the case of motors used in vehicles, miniaturization has been achieved from the perspective of vehicle integration, and more precise control has been implemented to make the use of these miniaturized motors more efficient.

[0003] It is known that the motor shaft generates shaft current and shaft voltage. If this current passes through the inside of the bearing, it can sometimes cause electrolytic corrosion in the metal raceways and rolling elements. Therefore, for example, in Patent Document 1 below, a filament 30 (grounding brush) is brought into contact with the shaft 16 of the motor 12, and the charge generated on the shaft 16 is released to the housing via the filament 30, thereby preventing current from passing through the inside of the bearing (see Patent Document 1). Figure 2 (etc.). In addition, in Patent Document 2 below, the release body 8 (region 10) is brought into contact with the shaft 68, and the charge generated on the shaft 68 is released to the housing 69 via the release body 8 to prevent current from passing through the bearing (see Figure 24 of Patent Document 2, etc.).

[0004] In addition, for example, in Patent Document 3 below, the brush 32 is housed in the bearing 1 that supports the motor shaft, and the brush 32 is subjected to force by the spring 31, so that the specified power supply performance is ensured even if the brush 32 is worn.

[0005] Patent Document 1: US Patent No. 8,199,453

[0006] Patent Document 2: Japanese Patent No. 7033538

[0007] Patent Document 3: Japanese Patent No. 6777178

[0008] The structures shown in Patent Documents 1 and 2 release charge by making the sliding contact components (filament 30, release body 8) slide into contact with the motor shafts (shaft 16, shaft 68). Therefore, there is a concern that the electrical conductivity of the sliding contact components will decrease due to wear and deformation over time, and the anti-electro-erosion effect will become insufficient.

[0009] Furthermore, the structure shown in Patent Document 3 is based on use in a dry environment, and includes a sealing element 7 and a labyrinth gap S in the bearing 1 and the brush 32 for sealing. Therefore, when used in an oil bath, the axial flow of lubricating oil is hindered, and ample space is required for installing the bearing unit (bearing 1), resulting in limitations on usage and installation conditions. Summary of the Invention

[0010] The problems to be solved by the present invention are as follows: the first problem is to provide an electric current unit and a bearing unit that can maintain the anti-electro-erosion effect for a long time; the second problem is to provide an electric current unit that is suitable for use in an oil bath and is compact, and a bearing unit that has the function of preventing electro-erosion.

[0011] To solve the first problem mentioned above, the present invention provides an energized unit (first structure) comprising:

[0012] The annular outer shell body has a circumferential groove that opens toward the inner diameter side and is conductive;

[0013] An electrically conductive component, disposed within the aforementioned peripheral groove, protrudes radially inward from the main body of the outer casing and is conductive; and

[0014] A radial elastic member is disposed within the aforementioned circumferential groove, which applies a radial inward force to the aforementioned energized member.

[0015] This creates a new bypass path for current to pass through the motor shaft and housing, preventing electrolytic corrosion of the bearing located between the motor shaft and housing. Furthermore, by applying force to the energized components toward the motor shaft through the radial elastic member, the contact between the motor shaft and the energized components can be maintained even as the energized components wear over time, thus sustaining the anti-electrolytic corrosion effect over a long period.

[0016] The preferred configuration is (second structure), which, in the first structure, has a pressing mechanism that presses the energized component from one side to the other in the axial direction within the aforementioned circumferential groove.

[0017] In this way, by pressing the energized component from one side of the axial direction to the other through the pressing mechanism, the contact state between the energized component and the main body of the housing can be maintained, thus enabling stable energization performance.

[0018] Preferably, in the second structure, the pressing mechanism is a curved portion formed on at least one of the pair of walls constituting the peripheral groove and bent toward the inner side of the peripheral groove on the inner diameter side relative to the outer diameter side. Alternatively, in the second structure, the pressing mechanism is an axially elastic member sandwiched in the axial gap between the inner surface of the peripheral groove and the energized component. According to these structures, the energized component can be pressed from one side of the axial direction to the other, and the contact state between the energized component and the main body of the housing can be reliably maintained.

[0019] Furthermore, to address the second issue mentioned above, a preferred configuration (fifth structure) is provided, in which an oil hole is formed in the main body of the outer casing to allow axial flow of lubricating oil. This improves the axial flow of lubricating oil inside the bearing when used in an oil bath in conjunction with the energized unit, and prevents electrolytic corrosion of the bearing.

[0020] A preferred configuration (sixth structure) is provided, in which the main body of the outer casing has a bearing fitting portion extending axially. This allows for easy integration of the power supply unit and the bearing used in conjunction with the power supply unit.

[0021] A preferred configuration (seventh structure) is provided, in which, in the sixth structure, an insulating portion is provided on at least one of the radially inner surface of the bearing mating portion or the surface of the housing body facing the extending direction of the bearing mating portion. This prevents current from flowing between the housing body and the bearing used in conjunction with the energizing unit, and more reliably prevents electrical erosion of the bearing.

[0022] The aforementioned insulating portion is preferably made of a material with high insulation properties. Examples of such materials include various ceramics and various resins. From the viewpoints of insulation resistance, insulation breakdown voltage, mechanical strength, and processability, a sintered film containing at least one of various ceramics, polyphenylene sulfide resin, polyamide-imide resin, and epoxy resin is preferred.

[0023] The preferred configuration (eighth structure) includes multiple energized components in the first to seventh structures. This ensures that even if the energizing performance of some energized components is compromised, it can be covered by other energized components, thus guaranteeing stable energizing performance.

[0024] A preferred configuration (ninth structure) is found in the eighth structure, where the main body of the housing has an annular outer ring and a retaining ring fitted into the outer ring. Multiple bends are formed on the retaining ring, and these bends arrange multiple energized components at equal intervals along the circumference. This allows for a self-aligning function based on radially elastic members applying inward force to the energized components housed between the multiple bends, thereby stabilizing the contact between the motor shaft and the energized components.

[0025] Furthermore, in this invention, a bearing unit (tenth structure) is constructed, wherein:

[0026] The first to ninth structures involve an electrified unit and a bearing, which have an outer ring, an inner ring disposed on the inner diameter side of the outer ring, a rolling element disposed between the outer ring and the inner ring, and a retainer that holds the rolling element at predetermined intervals along the circumferential direction, and are integrated into the bearing by means of the electrified unit.

[0027] In particular, in structures five through seven, when used in an oil bath, the axial flow of lubricating oil inside the bearing unit can be improved, and the bearing seals and labyrinth structure are not required, thereby enabling the miniaturization of the bearing unit while preventing bearing electrolytic corrosion.

[0028] A preferred configuration is (eleventh structure), in which the outer ring is configured to abut against the energizing unit. Alternatively, a preferred configuration is (twelfth structure), in which the end face of the outer ring is configured to abut against the energizing unit.

[0029] Alternatively, a preferred configuration (the thirteenth structure) is provided, in which the outer periphery of the main body of the outer casing is fitted into the inner diameter surface of the outer ring, and the energized component is subjected to force to make sliding contact with the motor shaft inserted into the center of the inner ring.

[0030] Alternatively, it can be configured as (the fourteenth structure), having: the energizing unit involved in the sixth or seventh structure; and a bearing having an outer ring, an inner ring disposed on the inner diameter side of the outer ring, rolling elements disposed between the outer ring and the inner ring, and a retainer holding the rolling elements at predetermined intervals along the circumference. The bearing fitting portion is fitted into the outer diameter surface of the outer ring, and the energizing component is forceped to make sliding contact with a motor shaft inserted into the center of the inner ring, or with the outer diameter surface of the inner ring. In this way, the energizing unit and the bearing can be easily integrated. Furthermore, if the energizing component makes sliding contact with the outer diameter surface of the inner ring instead of directly sliding contact with the motor shaft, special machining or processing methods for achieving a specified surface roughness and hardness of the motor shaft are not required, potentially leading to cost reduction.

[0031] Alternatively, it can be configured as (the fifteenth structure), having: the energizing unit involved in the seventh structure; and a bearing having an outer ring, an inner ring disposed on the inner diameter side of the outer ring, rolling elements disposed between the outer ring and the inner ring, and a retainer that holds the rolling elements at predetermined intervals along the circumference, wherein the insulating portion is in contact with at least one of the outer diameter surface or end face of the outer ring. This prevents current from flowing between the housing body and the outer ring, and more reliably prevents electrolytic corrosion of the bearing.

[0032] According to the energizing unit of the present invention, a new bypass path is formed to allow current to pass through the motor shaft and housing, thus preventing electrolytic corrosion of the bearing located between the motor shaft and the housing. Furthermore, by applying force to the energizing component toward the motor shaft through the elastic member, even if the energizing component wears over time, the contact state between the motor shaft and the energizing component can be maintained, thus sustaining the anti-electrolytic corrosion effect of the bearing unit for a long time. In addition, by forming oil holes in the housing body that allow lubricating oil to flow axially, the axial fluidity of the lubricating oil inside the bearing unit can be improved when used in an oil bath, and the bearing seals and labyrinth structure are not required, thereby preventing bearing electrolytic corrosion while miniaturizing the bearing unit. Attached Figure Description

[0033] Figure 1 This is a cross-sectional view showing a first embodiment of a bearing unit employing the energizing unit involved in this invention.

[0034] Figure 2 It is along Figure 1 A sectional view along line II-II in the diagram.

[0035] Figure 3 yes Figure 1 An exploded perspective view of the energized unit shown.

[0036] Figure 4 This is a cross-sectional view showing a second embodiment of a bearing unit employing the energizing unit involved in this invention.

[0037] Figure 5 It is along Figure 4 A cross-sectional view of the VV line.

[0038] Figure 6 yes Figure 4 A cross-sectional view of the main part of the energized unit shown.

[0039] Figure 7 yes Figure 4 An exploded perspective view of the energized unit shown.

[0040] Figure 8 yes Figure 4 A cross-sectional view of the main part of the first modified example of the energized unit shown.

[0041] Figure 9 yes Figure 4 A cross-sectional view of the main part of the second modified example of the energized unit shown.

[0042] Figure 10 yes Figure 4 A cross-sectional view of the main part of the third variant of the energized unit shown.

[0043] Figure 11 yes Figure 4 A cross-sectional view of a modified example of the bearing unit shown.

[0044] Figure 12 This is a cross-sectional view showing a third embodiment of the bearing unit (energized unit) according to the present invention.

[0045] Figure 13 It is along Figure 12 A cross-sectional view of line XIII-XIII in the diagram.

[0046] Figure 14 yes Figure 12 An enlarged sectional view of the bearing unit (energized unit) shown.

[0047] Figure 15 yes Figure 12 An exploded perspective view of the energized unit shown.

[0048] Figure 16 It means Figure 12 A cross-sectional view of a modified example of the bearing unit (energized unit) shown.

[0049] Figure 17 It means Figure 12 A cross-sectional view of another variation of the bearing unit (energized unit) shown.

[0050] Figure 18 This is a cross-sectional view showing the fourth embodiment of the bearing unit (electric unit) according to the present invention.

[0051] Figure 19 This is a cross-sectional view showing the fifth embodiment of the bearing unit (energized unit) according to the present invention. Detailed Implementation

[0052] The accompanying drawings show bearing unit A employing the energizing unit 1 involved in this invention. For example... Figures 1-3 As shown, the energizing unit 1 mainly consists of a housing body 2, an energizing component 3, and a radial elastic component 4. The energizing unit 1 is sandwiched between the motor shaft 5 and the housing 6, adjacent to a bearing 7 (a ball bearing in this embodiment). The bearing 7 is sandwiched between the motor shaft 5 (e.g., axle) and the housing 6 and supports the motor shaft 5. The housing 6 is electrically grounded.

[0053] From the perspective of anti-electrolytic corrosion effect, such as Figure 1 As shown, it is preferable to arrange the energizing unit 1 and the bearing 7 in axial contact, but a structure with a gap between them is also permissible. Hereinafter, the direction along the rotation axis of the motor shaft 5 will be referred to as the axial direction, the direction perpendicular to the rotation axis will be referred to as the radial direction, and the direction along the circumference of the rotation axis will be referred to as the circumferential direction.

[0054] The outer casing body 2 is a conductive annular component embedded in the inner diameter surface of the casing 6. The outer casing body 2 consists of an annular outer ring 8 and a retaining ring 9. The outer ring 8 has a flange extending in one axial direction on its outer periphery, and the retaining ring 9 has a flange extending in the opposite axial direction on its outer periphery. Figure 1 As shown, the flange formed on the outer ring portion 8 and the flange formed on the retaining ring 9 are integrated by press-fitting. Alternatively, after inserting the flange formed on the retaining ring 9 into the flange formed on the outer ring portion 8, a retaining ring can be provided on the web to fix the outer ring portion 8 and the retaining ring 9, thereby improving maintainability.

[0055] Both the outer ring 8 and the retaining ring 9 are made of steel. An axial gap is formed between the outer ring 8 and the retaining ring 9 after they are fitted together, which is capable of accommodating the energized component 3 and the radial elastic component 4. A plurality of bends 10 are formed at predetermined angular intervals on the retaining ring 9, and the plurality of bends 10 extend from the inner edge of the retaining ring 9 in the aforementioned other axial direction (the same direction as the flange formed on the retaining ring 9).

[0056] The energizing component 3 is an arc-shaped component that protrudes radially inward from the outer casing body 2, slides in contact with the motor shaft 5 supported by the bearing 7, and is conductive. One energizing component 3 is housed between each of the circumferentially adjacent bends 10 formed on the retaining ring 9. In this embodiment, four energizing components 3 are arranged at equal intervals circumferentially. The number of energizing components 3 can be appropriately varied, but is preferably multiple. The number of bends 10 formed on the retaining ring 9 is determined corresponding to the number of energizing components 3. In this embodiment, polytetrafluoroethylene (PTFE) with added carbon is used as the raw material for the energizing component 3. The inner diameter surface of the energizing component 3 is formed by a portion of a cylindrical surface and is in surface contact with the outer peripheral surface of the motor shaft 5. An outer peripheral groove 11 is formed on the outer peripheral edge of the energizing component 3.

[0057] As the raw material for the electrically conductive component 3, in addition to PTFE with added carbon, other materials that impart conductivity, such as metals, carbon, or polyether ether ketone (PEEK) with added carbon, resins, rubbers, ceramics, or composites thereof, can be used. Furthermore, surface treatments such as coatings that improve conductivity and wear resistance (e.g., conductive diamond-like carbon (DLC) coatings, metal coatings (platings, etc.)) can be applied to the surface of the electrically conductive component 3 (especially the inner diameter surface that slides in contact with the motor shaft 5).

[0058] The radial elastic member 4 is used to apply a radial inward force to the energized member 3 toward the motor shaft 5 (see reference). Figure 2 The component with the arrow in it. For example... Figure 2As shown, the radial elastic member 4 is mounted across the peripheral groove 11 formed on the outer periphery of each energized member 3. In this embodiment, a clamping spring made by machining a spiral steel wire into a ring is used as the radial elastic member 4, but for example, a spring ring (C-shaped retaining ring) with a slit in a part of the ring, or a ring-shaped rubber can also be used. Furthermore, in this embodiment, all energized members 3 are subjected to force by one radial elastic member 4, but it is also possible to configure each energized member 3 to have a separate radial elastic member 4.

[0059] The function of the energizing unit 1 will be explained. The motor shaft 5 is inserted into the axis of the energizing unit 1. As the motor shaft 5 rotates, if the motor shaft 5 slides into contact with the inner diameter surface of the energizing component 3, which is subjected to force by the radial elastic member 4, this inner diameter surface gradually wears down. Even with this wear, the energizing component 3 is always subjected to force by the radial elastic member 4 towards the motor shaft 5, thus maintaining the contact state (energized state) between the motor shaft 5 and the energizing component 3.

[0060] The energized component 3 contacts the housing body 2 (at least one of the outer ring 8 or the retaining ring 9), forming an energized circuit as a bypass between the motor shaft 5, the energized component 3, the housing body 2, and the housing 6. By forming an energized circuit in this way, the current through the bearing 7 sandwiched between the motor shaft 5 and the housing 6 is reduced, preventing electrolytic corrosion of the components of the bearing 7.

[0061] The aforementioned energizing unit 1 releases the charge generated on the motor shaft 5 to the housing 6 via the energizing component 3 and the housing body 2, thus preventing electrolytic corrosion of the bearing 7 located between the motor shaft 5 and the housing 6. Furthermore, by applying a radially elastic member 4 to the energizing component 3 radially inward, i.e., toward the motor shaft 5, even if the energizing component 3 wears over time, the contact between the motor shaft 5 and the energizing component 3 can be maintained, thus sustaining the anti-electrolytic corrosion effect for a long time. In addition, the energizing component 3 uses an initial radial width that can withstand long-term use even if wear occurs over time.

[0062] In addition, the aforementioned energizing unit 1 ensures a large energizing area by making the inner diameter surface of the energizing component 3 contact the outer peripheral surface of the motor shaft 5. Therefore, it can increase the amount of current released from the motor shaft 5 to the housing 6 through the energizing unit 1, and can more effectively prevent the bearing 7 from electrolytic corrosion.

[0063] Furthermore, since the aforementioned energizing unit 1 is equipped with multiple energizing components 3, even if a fault occurs in which the energizing function of some energizing components 3 is impaired, the energizing function of the other energizing components 3 can still be ensured, thus reliably achieving the anti-electro-erosion effect. In addition, by utilizing the self-aligning function of the multiple energizing components 3, the contact state between the motor shaft 5 and each energizing component 3 can be stabilized, thereby further improving the anti-electro-erosion effect.

[0064] Furthermore, in the above embodiment, the motor shaft 5 is inserted through the axis of the energizing unit 1, and the energizing member 3 is subjected to radial inward force by the radial elastic member 4 to make it slide in contact with the motor shaft 5. However, it is also possible to reverse this configuration, in which the motor shaft 5 is provided on the outer diameter side of the energizing unit 1 and the housing 6 is provided on the inner diameter side of the energizing unit 1, and the energizing member 3 is subjected to radial outward force by the radial elastic member 4.

[0065] In the first embodiment, such as Figure 1 As shown, the energizing unit 1 and the bearing 7 constituting the bearing unit A are separate components, but for example, they can also be configured such that the flange of the outer ring portion 8 of the energizing unit 1 extends axially toward the outer ring of the bearing 7, so that the energizing unit 1 and the bearing 7 are integrated.

[0066] Figure 4 This describes a second embodiment of a bearing unit A employing the energizing unit 1 according to the present invention. The bearing unit A comprises an energizing unit 1 and a bearing 7 (a ball bearing in this embodiment). The bearing 7 has an outer ring 12, an inner ring 13 disposed on the inner diameter side of the outer ring 12, rolling elements 14 disposed between the outer ring 12 and the inner ring 13, and a retainer 15 that holds the rolling elements 14 at predetermined intervals along the circumferential direction. The energizing unit 1 abuts against the outer ring 12 of the bearing 7.

[0067] like Figures 4-7 As shown, the energizing unit 1 mainly consists of a housing body 2, an energizing component 3, a radial elastic component 4, and a pressing mechanism 16. The energizing unit 1 is sandwiched between the motor shaft 5 and the housing 6, adjacent to a bearing 7. The bearing 7 is sandwiched between the motor shaft 5 (e.g., axle) and the housing 6 and supports the motor shaft 5. The housing 6 is electrically grounded. Hereinafter, the direction along the rotation axis of the motor shaft 5 will be referred to as the axial direction, the direction perpendicular to the rotation axis will be referred to as the radial direction, and the direction along the circumference of the rotation axis will be referred to as the circumferential direction.

[0068] The outer casing body 2 is a conductive annular component embedded in the casing 6. The outer casing body 2 has: an annular outer ring 8 having a flange 17 extending axially in one direction along its outer periphery and an extension piece 18 extending radially inward from its outer periphery; and an annular retaining ring 9 having a flange 19 extending axially in the opposite direction to the aforementioned direction along its outer periphery and an extension piece 20 extending radially inward from its outer periphery. Figure 4 As shown, the flange 17 formed on the outer ring portion 8 and the flange 19 formed on the retaining ring 9 are integrated by press-fitting. Along with this integration, circumferential grooves opening towards the inner diameter are formed by the flanges 17 and 19 formed on the outer ring portion 8 and the retaining ring 9, respectively, and the extension pieces 18 and 20. Furthermore, after inserting the flange 19 formed on the retaining ring 9 into the flange 17 formed on the outer ring portion 8, a retaining ring can be provided on the web surface to fix the outer ring portion 8 and the retaining ring 9, thereby improving maintainability.

[0069] Both the outer ring 8 and the retaining ring 9 are made of steel. The axial clearance of the circumferential groove formed by the integration of the outer ring 8 and the retaining ring 9 is set to be slightly larger than the axial width of the energized component 3, so that the energized component 3 can move freely in the radial direction. A plurality of bends 10 are formed at predetermined angular intervals on the retaining ring 9, and the plurality of bends 10 extend from the inner edge of the extension piece 20 in the aforementioned other axial direction (the same direction as the flange 19 formed on the retaining ring 9).

[0070] The energizing component 3 is an arc-shaped component that is disposed within a circumferential groove, protrudes radially inward from the main body 2 of the outer casing, slides in contact with the motor shaft 5, and is conductive. One energizing component 3 is housed between each of the circumferentially adjacent bends 10 formed on the retaining ring 9. In this embodiment, four energizing components 3 are arranged at equal intervals circumferentially. The number of energizing components 3 can be appropriately varied, but is preferably multiple. The number of bends 10 formed on the retaining ring 9 is determined corresponding to the number of energizing components 3. In this embodiment, polytetrafluoroethylene (PTFE) with added carbon is used as the raw material for the energizing component 3. The inner diameter surface of the energizing component 3 is formed by a portion of a cylindrical surface and is in surface contact with the outer circumferential surface of the motor shaft 5. An outer circumferential groove 11 is formed on the outer periphery of the energizing component 3.

[0071] As the raw material for the electrically conductive component 3, in addition to PTFE with added carbon, conductive materials such as metals, carbon, or carbon-added polyether ether ketone (PEEK) resins, rubbers, ceramics, or composites thereof that impart conductivity can also be used. In addition, surface processing such as coatings (e.g., conductive diamond-like carbon (DLC) coatings, metal coatings (platings, etc.) that improve conductivity and wear resistance can be applied to the surface of the electrically conductive component 3 (especially the inner diameter surface that slides in contact with the motor shaft 5).

[0072] The radial elastic component 4 is disposed within the circumferential groove and is used to apply radial inward force to the energized component 3 (see reference). Figure 5 The component with the arrow in it. For example... Figure 5 As shown, the radial elastic member 4 is mounted across the outer peripheral groove 11 formed in each energized member 3. In this embodiment, a clamping spring made by machining a spiral steel wire into a ring is used as the radial elastic member 4, but for example, a spring ring (C-shaped retaining ring) with a slit in a part of the ring, or a ring-shaped rubber can also be used. Furthermore, in this embodiment, all energized members 3 are subjected to force by one radial elastic member 4, but it is also possible to configure each energized member 3 to have a separate radial elastic member 4.

[0073] The pressing mechanism 16 is a mechanism for pressing the energized component 3 from one side of the axial direction to the other. In this embodiment, the pressing mechanism 16 is a bent portion 16a formed in at least one of the pair of wall portions (outer ring portion 8 and extension pieces 18, 20 of retaining ring 9) constituting the circumferential groove, which bends towards the inner side of the circumferential groove relative to the outer diameter side. More specifically, the bent portion 16a is formed by tilting the extension piece 18 of the outer ring portion 8 entirely at a predetermined angle relative to the radial direction towards the inner side of the circumferential groove, starting from the connection portion with the flange 17. Alternatively, the bent portion 16a may be formed only in the retaining ring 9, or it may be formed in both the outer ring portion 8 and the retaining ring 9.

[0074] The function of the energizing unit 1 will be explained. The motor shaft 5 is inserted into the axis of the energizing unit 1. As the motor shaft 5 rotates, if the motor shaft 5 slides into contact with the inner diameter surface of the energizing component 3, which is subjected to force by the radial elastic member 4, this inner diameter surface gradually wears down. Even with this wear, the energizing component 3 is always subjected to force by the radial elastic member 4 towards the motor shaft 5, thus maintaining the contact state (energized state) between the motor shaft 5 and the energizing component 3.

[0075] The energizing component 3 is pressed towards the retaining ring 9 by the pressing mechanism 16 (the curved portion 16a of the extension piece 18 formed in the outer ring portion 8). As a result, the axial clearance between the energizing component 3 and the outer housing body 2 (outer ring portion 8 and retaining ring 9) disappears, forming a bypass energizing circuit between the motor shaft 5, the energizing component 3, the outer housing body 2, and the housing 6. By forming this energizing circuit, the current through the bearing 7 sandwiched between the motor shaft 5 and the housing 6 is reduced, preventing electrolytic corrosion of the components of the bearing 7.

[0076] The aforementioned energizing unit 1 and bearing unit A release the charge generated on the motor shaft 5 to the housing 6 via the energizing component 3 and the housing body 2, thus preventing electrolytic corrosion of the bearing 7 located between the motor shaft 5 and the housing 6. Furthermore, by applying a radially inward force to the energizing component 3, i.e., toward the motor shaft 5, through the radial elastic component 4, even if the energizing component 3 wears over time, the contact between the motor shaft 5 and the energizing component 3 can be maintained, thus sustaining the anti-electrolytic corrosion effect for a long period. Moreover, as the energizing component 3, it is preferable to use an energizing component with an initial radial width that can withstand long-term use even if wear occurs over time.

[0077] In addition, the aforementioned power-conducting unit 1 and bearing unit A press the power-conducting component 3 from one side of the axial direction to the other side through the bending portion 16a, which serves as the pressing mechanism 16. Therefore, the power-conducting component 3 can maintain contact with the housing body 2, and stable power-conducting performance can be achieved.

[0078] In addition, the aforementioned energizing unit 1 and bearing unit A ensure a large energizing area by having the inner diameter surface of the energizing component 3 in contact with the outer peripheral surface of the motor shaft 5. This increases the amount of current released from the motor shaft 5 to the housing 6 via the energizing unit 1, and more effectively prevents electrolytic corrosion of the bearing 7.

[0079] Furthermore, since the aforementioned energizing unit 1 and bearing unit A are equipped with multiple energizing components 3, even if a fault occurs in which the energizing function of some energizing components 3 is impaired, the energizing function of the other energizing components 3 can be ensured, thus reliably achieving the anti-electro-erosion effect. In addition, by utilizing the self-aligning function of multiple energizing components 3, the contact state between the motor shaft 5 and each energizing component 3 can be stabilized, thereby further improving the anti-electro-erosion effect.

[0080] Figure 8 This represents a first modified example of the energizing unit 1. The energizing unit 1 involved in the first modified example is related to... Figure 4 The basic structure of the energizing unit 1 shown is the same, but the difference lies in that the bent portion 16a, which serves as the pressing mechanism 16, is only formed on a portion of the inner diameter front end of the extension piece 18 of the outer ring portion 8. In this structure, the energizing member 3 can also be pressed from one side of the axial direction to the other via the bent portion 16a, thus maintaining the contact state between the energizing member 3 and the housing body 2, and achieving stable energizing performance. Furthermore, compared with… Figure 4 Similarly, the energizing unit 1 shown can also be configured such that only the retaining ring 9 has a bent portion 16a, or it can be configured such that both the outer ring 8 and the retaining ring 9 have bent portions 16a.

[0081] Figure 9 This represents a second variation of the energizing unit 1. The energizing unit 1 involved in the second variation is related to... Figure 4The basic structure of the energizing unit 1 shown is the same, but the difference lies in that the pressing mechanism 16 is an axially elastic member 16b sandwiched in the axial gap between the inner surface of the circumferential groove and the energizing member 3. In this structure, the energizing member 3 can also be pressed from one side of the axial direction to the other by the axially elastic member 16b, thus maintaining the contact state between the energizing member 3 and the outer ring 8 of the outer casing, and achieving stable energizing performance. In the second variation, the axially elastic member 16b is configured to be sandwiched between the retaining ring 9 and the energizing member 3, but it can also be configured to be sandwiched between the outer ring 8 and the energizing member 3.

[0082] In the second variation of the energizing unit 1, the axial elastic member 16b may also be made of a conductive material, such as metal, carbon, or a conductive resin, rubber, ceramic, or a composite material thereof. This ensures multiple energizing paths, including one where current flows directly from the energizing member 3 to the outer casing body 2 (outer ring 8) and another where current flows from the energizing member 3 through the axial elastic member 16b to the outer casing body 2 (clamp ring 9), thus enabling more stable energizing performance.

[0083] Figure 10 This represents a third variation of the energizing unit 1. The energizing unit 1 involved in this third variation is related to... Figure 4 The basic structure of the energizing unit 1 shown is the same, but the difference is that the pressing mechanism 16 is an inclined surface 16c formed on the contact portion of the energizing member 3 that abuts against the radial elastic member 4, having a normal inclined to one side in the axial direction. The inclined surface 16c is inclined in such a way that it gets closer to the motor shaft 5 from the outer ring portion 8 side toward the retaining ring 9 side. When the radial elastic member 4 abuts against the inclined surface 16c, the radial component of the abutment force acts as a force pressing the energizing member 3 against the motor shaft 5, and the axial component acts as a force pressing the energizing member 3 against the extension piece 18 of the outer ring portion 8.

[0084] In this way, by tilting the face 16c, the force of the radial elastic member 4 is branched into radial and axial components, thereby maintaining the contact state between the energized member 3 and the motor shaft 5, and between the energized member 3 and the housing body 2 (outer ring 8), thus achieving stable energizing performance. Furthermore, it can also be used with... Figure 10 The structure shown is the opposite, so that the inclined face 16c is inclined in a way that it is closer to the motor shaft 5 from the side of the retaining ring 9 toward the side of the outer ring 8.

[0085] In the energized unit 1 involved in the third variation, and Figure 4Similarly, the radial elastic member 4 of the energizing unit 1 shown is preferably made of metal. This ensures multiple energizing paths, including one where current flows directly from the energizing member 3 to the outer casing body 2 (outer ring 8) and another where current flows from the energizing member 3 through the radial elastic member 4 to the outer casing body 2 (clamp ring 9), thus enabling more stable energizing performance.

[0086] Figure 11 This illustrates a variation of bearing unit A. This variation involves bearing unit A and... Figure 4 The bearing unit A shown has the same basic structure, but the difference is that in this bearing unit A, the energizing unit 1 and the bearing 7 are separate components, while the bearing unit A involved in the modified example has... Figure 4 The flange 17 of the outer ring portion 8 of the energizing unit 1 shown in the figure extends axially to the outer diameter side of the outer ring 12 of the bearing 7, forming a bearing unit A that integrates the energizing unit 1 and the bearing 7. This allows it to function in conjunction with… Figure 4 The energizing unit 1 and bearing unit A shown have the same effect, and the size of bearing unit A is the same as the main size of the bearing standardized in the Japanese Industrial Standard (JISB1512-1:2011), thereby enabling the bearing unit A with energizing unit 1 to be lightweight and narrow.

[0087] Furthermore, in the second embodiment, the motor shaft 5 is inserted through the axis of the energizing unit 1, and the energizing member 3 is subjected to radial inward force by the radial elastic member 4 to make it slide in contact with the motor shaft 5. However, it is also possible to reverse this configuration, in which the motor shaft 5 is provided on the outer diameter side of the energizing unit 1 and the housing 6 is provided on the inner diameter side of the energizing unit 1, and the energizing member 3 is subjected to radial outward force by the radial elastic member 4.

[0088] The third embodiment of the bearing unit A (energized unit 1) according to the present invention will be described with reference to the accompanying drawings. Figures 12-15 As shown, the bearing unit A according to the third embodiment has an energizing unit 1 and a bearing 7, which are integrated into one unit. The bearing unit A is sandwiched between the motor shaft 5 (such as the e-axle) and the housing 6, supporting the motor shaft 5 so that it can rotate freely. The housing 6 is electrically grounded. Hereinafter, the direction along the rotation axis of the motor shaft 5 will be referred to as the axial direction, the direction perpendicular to the rotation axis will be referred to as the radial direction, and the direction along the circumference of the rotation axis will be referred to as the circumferential direction.

[0089] The energizing unit 1 has: an annular outer shell body 2 that is conductive; an energizing component 3 that protrudes radially inward from the outer shell body 2 and is conductive; and a radially elastic component 4 that applies force radially inward to the energizing component 3.

[0090] The outer casing body 2 includes: an annular outer ring portion 8 having a flange 17 extending axially in one direction along its outer periphery and an extension piece 18 extending radially inward from its outer periphery; and an annular retaining ring 9 having a flange 19 extending axially in the opposite direction to the aforementioned direction along its outer periphery and an extension piece 20 extending radially inward from its outer periphery. Multiple oil holes 21 and 22 are formed at predetermined circumferential angles on the extension pieces 18 and 20 of the outer ring portion 8 and the retaining ring 9 (in this embodiment, four oil holes 21 and 22 are formed at 90-degree intervals). A bearing fitting portion 23 extends from the flange 17 of the outer ring portion 8 toward the aforementioned direction.

[0091] like Figure 14 As shown, the flange 17 formed on the outer ring portion 8 and the flange 19 formed on the retaining ring 9 are integrated by press-fitting. In this integrated state, the circumferential positions of the oil hole 21 formed on the outer ring portion 8 and the oil hole 22 formed on the retaining ring 9 are aligned. Along with this integration, circumferential grooves opening towards the inner diameter are formed by the flanges 17 and 19 formed on the outer ring portion 8 and the retaining ring 9, respectively. Furthermore, after inserting the flange 19 formed on the retaining ring 9 into the flange 17 formed on the outer ring portion 8, a retaining ring can be provided on the web surface to fix the outer ring portion 8 and the retaining ring 9, thereby improving maintainability.

[0092] Both the outer ring 8 and the retaining ring 9 are made of steel. An axial gap is formed between the fitted outer ring 8 and the retaining ring 9 to accommodate the energized component 3 and the radially elastic component 4. Multiple (four in this embodiment) bends 10 are formed at predetermined angular intervals on the retaining ring 9, extending from the inner edge of the retaining ring 9 in the aforementioned axial direction (the same direction as the flange 19 formed on the retaining ring 9). Each bend 10 is formed corresponding to the circumferential center position of the oil hole 22 formed on the retaining ring 9.

[0093] The energizing component 3 has a generally arc-shaped base 24 and an energizing portion 25 that protrudes radially inward from the base 24, configured such that the energizing portion 25 slides in contact with the motor shaft 5. One energizing component 3 is housed between each of the circumferentially adjacent bends 10 formed on the retaining ring 9. In this embodiment, four energizing components 3 are arranged at equal intervals circumferentially. The number of energizing components 3 can be appropriately varied, but is preferably multiple. The number of bends 10 formed on the retaining ring 9 is determined corresponding to the number of energizing components 3. In this embodiment, polytetrafluoroethylene (PTFE) with added carbon is used as the raw material for the energizing portion 25. An outer peripheral groove 11 is formed on the outer periphery of the base 24.

[0094] As raw materials for the electrified section 25, in addition to PTFE with added carbon, other materials such as metals, carbon, or polyether ether ketone (PEEK) with added carbon can be used to impart conductivity, as well as resins, rubbers, ceramics, or composite materials thereof. This allows for ensuring the electrification performance of the electrified unit with a simple structure. Furthermore, surface treatments such as coatings that improve conductivity and wear resistance (e.g., conductive diamond-like carbon (DLC) coatings, metal coatings (platings, etc.)) can be applied to the surface of the electrified section 25 (especially the part that slides in contact with the motor shaft 5).

[0095] The radial elastic member 4 is used to apply a radial inward force to the energized member 3 toward the motor shaft 5 (see reference). Figure 13 The component with the arrow in it. For example... Figure 13 As shown, the radial elastic member 4 is mounted across the peripheral groove 11 formed on the outer periphery of each energized member 3. In this embodiment, a clamping spring made by machining a spiral steel wire into a ring is used as the radial elastic member 4, but for example, a spring ring (C-shaped retaining ring) with a slit in a part of the ring, or a ring-shaped rubber can also be used. Furthermore, in this embodiment, all energized members 3 are subjected to force by one radial elastic member 4, but it is also possible to configure each energized member 3 to have a separate radial elastic member 4.

[0096] The bearing 7 is a ball bearing having an outer ring 12, an inner ring 13 disposed on the inner diameter side of the outer ring 12, rolling elements 14 disposed between the outer ring 12 and the inner ring 13, and retainers 15 holding the rolling elements 14 at predetermined intervals along the circumference. In this embodiment, the bearing 7 does not have a seal, ensuring the axial flow of lubricating oil inside the bearing unit A. The bearing fitting portion 23 formed on the outer ring portion 8 of the housing body 2 fits into the outer diameter surface of the outer ring 12, thereby integrating the energizing unit 1 with the bearing 7.

[0097] Bearing unit A is designed such that the inner diameter, outer diameter, and axial width of bearing unit A, when the energized unit 1 and bearing 7 are integrated, are consistent with any combination of the main dimensions of bearings (bearing inner diameter d, bearing outer diameter D, bearing width B) standardized in Japanese Industrial Standard JIS B1512-1:2011.

[0098] The function of bearing unit A will be explained. Motor shaft 5 is inserted into the axis of bearing unit A (energized unit 1 and bearing 7). If motor shaft 5 slides into contact with the energized part 25 of energized component 3, which is subjected to force towards motor shaft 5 by the radial elastic member 4, the sliding contact portion of energized part 25 with motor shaft 5 will gradually wear. Even with this wear, energized component 3 (energized part 25) is always subjected to force towards motor shaft 5 by the radial elastic member 4, thus maintaining the contact state (energized state) between motor shaft 5 and energized component 3.

[0099] The energized part 25 contacts the outer housing body 2 (at least one of the outer ring 8 or the retaining ring 9), forming a bypass energizing circuit between the motor shaft 5, the energized part 25, the outer housing body 2, and the housing 6. By forming the energizing circuit in this way, the current passing through the bearing 7 sandwiched between the motor shaft 5 and the housing 6 is reduced.

[0100] The bearing unit A described above has oil holes 21 and 22 formed in the housing body 2 to allow lubricating oil to flow in the axial direction. Therefore, when used in an oil bath, the axial flow of lubricating oil inside the bearing unit A can be improved, and the seals and labyrinth structure of the bearing 7 are not required. This allows the bearing unit A to be miniaturized while preventing electrolytic corrosion of the bearing 7.

[0101] Furthermore, since the aforementioned bearing unit A is equipped with multiple energized components 3, even if a fault occurs in which the energizing function of some energized components 3 is impaired, the energizing function of the other energized components 3 can still be ensured, thus reliably achieving the anti-electro-erosion effect. In addition, by utilizing the self-aligning function of the multiple energized components 3, the contact state between the motor shaft 5 and each energized component 3 can be stabilized, thereby further improving the anti-electro-erosion effect.

[0102] Furthermore, the bearing unit A described above is configured such that its inner diameter, outer diameter, and axial width, when the power supply unit 1 and the bearing 7 are integrated, are consistent with any combination of the main dimensions of the bearings standardized in Japanese Industrial Standard JISB1512-1:2011. Therefore, the bearings (standard bearings, basic bearings) standardized in the aforementioned Japanese Industrial Standard can be directly replaced with the bearing unit A involved in this invention.

[0103] Figure 16 This illustrates a variation of the bearing unit A (energized unit 1) according to the third embodiment. The bearing unit A in this variation differs from the structure described above in that an insulating portion 26 is formed on the inner surface (the surface facing the outer ring 12 of the bearing 7) of the bearing fitting portion 23 formed in the outer ring portion 8. By forming the insulating portion 26 between the bearing fitting portion 23 and the outer diameter surface of the outer ring 12, current flow between the outer ring portion 8 and the outer ring 12 can be prevented, thus more reliably preventing electrolytic corrosion of the bearing 7. In this variation, as... Figure 17 As shown, by further forming an insulating portion 26 between the outer housing body 2 (the extension piece 20 of the retaining ring 9) and the end face of the outer ring 12, the resistance to electrolytic corrosion of the bearing 7 can be further improved. Alternatively, the insulating portion 26 can be provided only between the end face of the outer housing body 2 (the extension piece 20 of the retaining ring 9) and the outer ring 12.

[0104] Figure 18This describes a fourth embodiment of the bearing unit A (energized unit 1) according to the present invention. The bearing unit A in the fourth embodiment shares similarities with the bearing unit A in the third embodiment in that the energized unit 1 and the bearing 7 are integrated by fitting the bearing fitting portion 23 formed on the outer ring portion 8 of the housing body portion 2 with the outer diameter surface of the outer ring 12. On the other hand, the difference lies in that, in a pair of shoulder portions formed on the outer diameter surface of the inner ring 13, one of the shoulder portions has a longer axial length than the other, and the energized component 3 (energized portion 25) slides in contact with this shoulder portion (outer diameter surface of the inner ring 13).

[0105] In the structure according to the fourth embodiment, a bypass power supply circuit is formed between the motor shaft 5, the inner ring 13, the energized part 25, the outer housing body 2, and the housing 6. By forming the power supply circuit in this way, the current transmitted through the bearing 7 sandwiched between the motor shaft 5 and the housing 6 is reduced. According to this structure, the energized part 3 (energized part 25) does not directly slide in contact with the motor shaft 5, so there is no need for special processing or manufacturing methods to make the motor shaft 5 achieve a specified surface roughness and hardness, which can potentially reduce costs.

[0106] Figure 19 This represents a fifth embodiment of the bearing unit A (energized unit 1) according to the present invention. The bearing unit A in the fifth embodiment shares similarities with the bearing unit A in the third embodiment in that the energized component 3 (energized part 25) is forced by the radial elastic component 4 to slide into contact with the motor shaft 5 inserted into the axis of the inner ring 13. On the other hand, the difference lies in that one of the two shoulder grooves formed on the inner diameter surface of the outer ring 12 has a longer axial length than the other, and the outer periphery of the housing body 2 is fitted into this one shoulder groove (the inner diameter surface of the outer ring 12).

[0107] In the structure according to the fifth embodiment, a bypass power supply circuit is formed between the motor shaft 5, the energizing unit 25, the housing body 2, the outer ring 12, and the housing 6. By forming the power supply circuit in this way, the current transmitted through the bearing 7 sandwiched between the motor shaft 5 and the housing 6 is reduced. According to this structure, no radially inward force is exerted from the energizing unit 1 on the outer ring 12, thus preventing the size of the internal clearance of the bearing from deviating from a predetermined appropriate value due to this force.

[0108] Furthermore, in the third to fifth embodiments, the motor shaft 5 is inserted through the axis of the bearing unit A, and the energized part 25 slides in contact with the outer diameter surface of the motor shaft 5 or the inner ring 13 by applying a radially inward force to the energized part 3 using the radial elastic member 4. However, it is also possible to reverse this configuration, in which the motor shaft 5 is provided on the outer diameter side of the bearing unit A and the housing 6 is provided on the inner diameter side of the bearing unit A, and the energized part 3 is applied a radially outward force using the radial elastic member 4.

[0109] The embodiments disclosed herein should be considered illustrative rather than limiting in all respects. The scope of the invention is indicated by the scope of protection claimed in this application rather than by the foregoing description, and is intended to include all modifications within the scope and meaning equivalent to the scope of protection claimed in this application.

[0110] Explanation of reference numerals in the attached figures

[0111] 1…Electrifying unit; 2…Main housing; 3…Electrifying component; 4…Radial elastic component; 5…Motor shaft; 7…Bearing; 8…Outer ring; 9…Snap ring; 10…Bending part; 12…Outer ring; 13…Inner ring; 14…Rolling element; 15…Retainer; 16…Pressing mechanism; 16a…Bending part; 16b…Axial elastic component; 16c…Inclined part; 21, 22…Oil holes; 23…Bearing fitting part; 26…Insulation part; A…Bearing unit.

Claims

1. A power-conducting unit, characterized in that, have: The annular outer shell body (2) has a circumferential groove that opens toward the inner diameter side and is conductive; An energized component (3) is disposed within the peripheral groove, protruding radially inward from the main body of the outer casing (2), and is conductive; and A radial elastic member (4) is disposed in the peripheral groove and applies a radial inward force to the energized member (3).

2. The energizing unit according to claim 1, characterized in that, It has a pressing mechanism (16) that presses the energized component (3) from one side to the other in the axial direction within the circumferential groove.

3. The energizing unit according to claim 2, characterized in that, The pressing mechanism (16) is a curved portion (16a) formed on at least one of the pair of wall portions constituting the peripheral groove and bent toward the inside of the peripheral groove on the inner diameter side relative to the outer diameter side.

4. The energizing unit according to claim 2, characterized in that, The pressing mechanism (16) is an axially elastic component (16b) sandwiched in the axial gap between the inner surface of the circumferential groove and the energized component (3).

5. The energizing unit according to claim 1, characterized in that, Oil holes (21, 22) are formed in the main body of the outer casing (2) to allow lubricating oil to flow in the axial direction.

6. The energizing unit according to claim 5, characterized in that, The outer shell body (2) has a bearing fitting part (23) that extends axially.

7. The energizing unit according to claim 6, characterized in that, An insulating portion (26) is provided on at least one of the radial inner side of the bearing fitting portion (23) or the surface of the housing body portion (2) facing the bearing fitting portion (23) in the extending direction.

8. The energizing unit according to any one of claims 1 to 7, characterized in that, The energized component (3) is provided in multiple forms.

9. The energizing unit according to claim 8, characterized in that, The outer casing body (2) has an annular outer ring (8) and a retaining ring (9) fitted into the outer ring (8). A plurality of bends (10) are formed in the retaining ring (9), and the plurality of bends (10) arrange the plurality of the power-conducting components (3) at equal intervals along the circumference.

10. A bearing unit, characterized in that, have: The energizing unit (1) according to any one of claims 1 to 9; and The bearing (7) has an outer ring (12), an inner ring (13) disposed on the inner diameter side of the outer ring (12), a rolling element (14) disposed between the outer ring (12) and the inner ring (13), and a retainer (15) holding the rolling element (14) at a predetermined interval in the circumferential direction. The energizing unit (1) is fitted into the bearing (7) so that the two are integrated.

11. The bearing unit according to claim 10, characterized in that, The outer ring (12) is configured to abut against the energized unit (1).

12. The bearing unit according to claim 11, characterized in that, The end face of the outer ring (12) is configured to abut against the energized unit (1).

13. The bearing unit according to claim 10, characterized in that, The outer periphery of the outer shell body (2) fits into the inner diameter surface of the outer ring (12). The energized component (3) is forced into sliding contact with the motor shaft (5) inserted into the center of the inner ring (13).

14. A bearing unit, characterized in that, have: The energizing unit (1) as described in claim 6 or 7; and The bearing (7) has an outer ring (12), an inner ring (13) disposed on the inner diameter side of the outer ring (12), a rolling element (14) disposed between the outer ring (12) and the inner ring (13), and a retainer (15) holding the rolling element (14) at a predetermined interval in the circumferential direction. The bearing fitting part (23) fits into the outer diameter surface of the outer ring (12). The energized component (3) is subjected to force to make sliding contact with the motor shaft (5) inserted into the center of the inner ring (13) or the outer diameter surface of the inner ring (13).

15. A bearing unit, characterized in that, have: The energizing unit (1) according to claim 7; and The bearing (7) has an outer ring (12), an inner ring (13) disposed on the inner diameter side of the outer ring (12), a rolling element (14) disposed between the outer ring (12) and the inner ring (13), and a retainer (15) holding the rolling element (14) at a predetermined interval in the circumferential direction. The insulating part (26) is in contact with at least one of the outer diameter surface or end face of the outer ring (12).

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