Drive device

Abstract

The invention relates to a driving device. The present invention suppresses an increase in size of a drive device and suppresses diffusion of wear powder in a housing, said wear powder being generated by an electrical connection member. A drive device (1) is provided with: a target bearing (B2) that rotatably supports a target rotating shaft (15) with respect to a housing (2); and an electrical connection member (3) that electrically connects the target rotating shaft (15) and the housing. A housing (2) is provided with a contact part (31) of an electrical connection member in a target space (E), which is a space between an opposing wall part (22) and the axial direction (L) of a target bearing (B2), the opposing wall part (22) being disposed closer to a first side (L1) in the axial direction than a bearing support part (21) for supporting the target bearing (B2) and facing the target bearing. A recess (5) formed so as to be partially recessed from an inner surface (23a) of a surrounding wall section (23) that surrounds a space to be treated from a radially outer side (R2) is provided to a lower portion of the surrounding wall section (23). The recess (5) is formed so as to be partially recessed toward the radially outer side (R2) from the inner surface (23a) of the surrounding wall section (23).

Description

TECHNICAL FIELD

[0001] The present application relates to a driving device. BACKGROUND

[0002] In Japanese Patent Application Publication No. 2016-119760, as one example of a driving device, a rotary electric machine (1) (in the background art, the reference numeral in parentheses is the reference numeral of the drawing of the reference literature) in which a rotor (3) and a stator (4) are housed in a housing (2) is disclosed. The rotor (3) is supported by a rotor shaft (31) that rotates integrally with the rotor (3), and the rotor shaft (31) is supported by the housing (2) so as to be rotatable via a bearing. In such a driving device, eddy current generated in the rotor (3) by a change in the magnetic field generated by the stator (4) sometimes becomes electromagnetic noise and is emitted from the driving device. Therefore, the rotary electric machine (1) has a grounding mechanism (7) that contacts the rotor shaft (31) and is used to discharge the eddy current to the housing (2) as an electrical connection member provided at an end portion (311) of the rotor shaft (31). The grounding mechanism (7) has an electrical brush (70) that contacts an end surface (311A) of the rotor shaft (31).

[0003] Here, if the electrical brush (70) contacts the end surface (311A) of the rotor shaft (31), abrasive powder having electrical conductivity is generated. If the abrasive powder spreads inside the housing (2), there is a concern that an electrical influence such as short circuit is caused to the stator (4), resolver (5), or the like, or a mechanical influence such as damage or wear is caused to the bearing. Therefore, in the rotary electric machine (1), the electrical brush (70) is housed in a housing portion (71) surrounded by a first member (72) and a second member (73) that are cylindrical with a bottom. The housing portion (71) is formed by a labyrinth structure in which the cylindrical wall (721) of the first member (72) and the cylindrical wall (731) of the second member (73) have a gap in the radial direction and overlap each other, and release of the abrasive powder outside the housing portion (71) can be suppressed.

[0004] Patent Literature 1: Japanese Patent Application Publication No. 2016-119760

[0005] In the above-described configuration, a space in which the cylindrical wall of the first member and the cylindrical wall of the second member are arranged in the radial direction of the rotor shaft is required, and from the end portion of the rotor shaft, a space in which the cylindrical wall is extended from both the one side and the other side in the axial direction is also required on the one side in the axial direction. Therefore, miniaturization of the driving device is easily hindered. SUMMARY

[0006] In view of the above-described background, it is desirable to be able to suppress the increase in size of the driving device and suppress the spread of abrasive powder generated by the electrical connection member inside the housing.

[0007] The drive device according to the above conditions includes: a rotor; a stator having coils; an object rotation shaft that transmits the rotation of the rotor; a housing that houses the rotor, the stator, and the object rotation shaft; an object bearing that supports the object rotation shaft so that it can rotate relative to the housing; and an electrical connection member that electrically connects the object rotation shaft and the housing, wherein the direction along the rotation axis of the object rotation shaft is defined as axial, the direction orthogonal to the rotation axis is defined as radial, and one side of the axial direction is defined as a first axial side, and the housing includes: a bearing support portion that supports... The device includes: a bearing support; a counter wall portion disposed on the first axial side of the bearing support portion and opposite to the bearing support portion on the first axial side; and a surrounding wall portion that surrounds the space between the counter wall portion and the bearing support portion on the axial side, i.e., the object space, on the radially outer side. The electrical connection member includes a contact portion that allows relatively rotating components to be electrically connected to each other by sliding contact. The contact portion is disposed in the object space. A recess is provided at the lower part of the surrounding wall portion in a manner that partially recesses from the inner surface of the surrounding wall portion towards the radially outer side.

[0008] According to this structure, when wear powder is generated due to sliding contact of the electrical connection components, the wear powder can be accumulated in the recess. This reduces the possibility of wear powder moving from the contact portion and affecting the bearing or other components. The recess for accumulating wear powder has a simple structure formed by recessing into the lower part of the inner surface surrounding the wall, thus easily preventing the drive unit from becoming too large. In other words, according to this structure, the large size of the drive unit can be suppressed, and the diffusion of wear powder generated by the electrical connection components within the housing can be suppressed.

[0009] Further features and advantages of the drive device will become apparent from the following description of illustrative and non-limiting embodiments illustrated with reference to the accompanying drawings. Attached Figure Description

[0010] Figure 1 It is a schematic diagram of a vehicle drive system.

[0011] Figure 2 This is a partially enlarged sectional view of a vehicle drive unit.

[0012] Figure 3 It is an enlarged portion of the axial view of a vehicle drive unit.

[0013] Figure 4 It is a partially enlarged 3D view of a vehicle drive unit.

[0014] Figure 5 This is a partially enlarged cross-sectional view of the vehicle drive unit of the first comparative example.

[0015] Figure 6 This is a partially enlarged cross-sectional view of the vehicle drive unit of the second comparative example.

[0016] Figure 7 This is a partially enlarged cross-sectional view of the vehicle drive unit of the third comparative example.

[0017] Figure 8 This is a partially enlarged cross-sectional view of the vehicle drive unit of the fourth comparative example.

[0018] Figure 9 This is a partially enlarged cross-sectional view of the vehicle drive unit of the fifth comparative example.

[0019] Explanation of reference numerals in the attached figures

[0020] 1: Vehicle drive unit (drive unit), 2: Housing, 3: Electrical connection component, 5: Recess, 10: Rotary motor (drive unit), 11: Rotor, 12: Stator, 13: Coil, 14: Rotor shaft (object rotation shaft), 15: Input shaft (object rotation shaft), 21: Bearing support, 22: Opposing wall, 23: Enclosing wall, 23a: Inner surface, 26: Guide path, 27: First support surface, 28: Second support surface, 31: Brush (contact part), 40: Sub-shaft (object rotation shaft), 51: Groove, 52: Hole, 53: Bottom, A1: First shaft (rotation axis of object rotation shaft), B1: Rotor bearing (object bearing), B2: Input bearing (object bearing), B4: Sub-bearing (object bearing), E: Object space, L: Axial, L1: First side of axial direction, R: Radial, R2: Outer side of radial direction, V2: Lower side (below). Detailed Implementation

[0021] Hereinafter, embodiments of the drive device will be described with reference to the accompanying drawings. In this embodiment, as... Figure 1 As shown, an example of a drive unit is a vehicle drive unit 1, which includes a rotary motor 10 that serves as the driving force source for the wheels W of a vehicle, a reverse gear mechanism 4 that serves as a reducer, and a differential gear mechanism 6 that distributes power to the two wheels W. While details will be described later, the vehicle drive unit 1 includes: a rotor 11; a stator 12 with coils 13; a rotating shaft (rotor shaft 14, input shaft 15, and auxiliary shaft 40) that transmits the rotation of the rotor 11; a housing 2 that houses the rotor 11, stator 12, and rotating shaft; a rotating bearing (rotor bearing B1, input bearing B2, and auxiliary bearing B4) that supports the rotating shaft relative to the housing 2 for rotation; and an electrical connection member 3 (see reference) that electrically connects the rotating shaft and the housing 2. Figure 2Furthermore, the drive device only needs to include at least a rotary motor 10. That is, the drive device may also include: a rotor 11; a stator 12 with coils 13; an object rotation shaft (rotor shaft 14 or input shaft 15) that transmits the rotation of the rotor 11; a housing 2 that houses the rotor 11, stator 12, and object rotation shaft; an object bearing (rotor bearing B1 or input bearing B2) that supports the object rotation shaft relative to the housing 2 so that it can rotate; and an electrical connection component 3 that electrically connects the object rotation shaft and the housing 2 (see reference). Figure 2 ) Rotary motor 10.

[0022] In this embodiment, a vehicle drive unit 1 with a three-axis structure is illustrated, in which rotating components are arranged on different parallel axes, namely, the first axis A1, the second axis A2, and the third axis A3, each serving as a rotation axis. A rotary motor 10 is mounted on the first axis A1. A reversing gear mechanism 4, which serves as a speed reducer to reduce the rotation of the rotor 11 of the rotary motor 10, is mounted on the second axis A2. A differential gear mechanism 6, which distributes the power transmitted from the rotor 11 via the speed reducer to a pair of wheels W, is mounted on the third axis A3. In the illustrated example, the differential gear mechanism 6 is a bevel gear type differential mechanism. A plurality of differential pinions 63 and a pair of differential side gears 62 are housed in a differential housing 60, which is connected to and rotates integrally with the differential input gear 61. The differential side gears 62 are connected to a pair of wheels W, for example, via a drive shaft 69.

[0023] In this embodiment, the direction along the first axis A1 is defined as the axial direction L, one side of the axial direction L is defined as the first axial side L1, and the other side is defined as the second axial side L2. Furthermore, the direction orthogonal to each axis is defined as the radial direction R, with each axis as a reference. The direction on the radial direction R that is close to the axis is defined as the radial inner side R1, and the direction that is away from the axis is defined as the radial outer side R2. Additionally, when the vehicle drive unit 1 is mounted on a vehicle, the direction along the vertical direction is defined as the up-down direction V, the area above the up-down direction V is defined as the upper side V1, and the area below it is defined as the lower side V2.

[0024] The rotary motor 10 is a traction motor that supplies power to the wheels W via a DC power supply (not shown) and generates electricity from the power transmitted from the wheels W, etc., and also functions as a generator to charge the DC power supply. The rotor 11 is supported by a rotor shaft 14 connected to and rotating integrally with the rotor 11. The rotor shaft 14 is supported by a pair of rotor bearings B1 sandwiching the rotor 11 and disposed on both sides along the axial direction L, allowing it to rotate relative to the housing 2. The rotor shaft 14 is connected to an input shaft 15 on the first axial side L1, and the rotor shaft 14 and the input shaft 15 rotate integrally. The input shaft 15 is supported by the housing 2 via input bearings B2 on the first axial side L1 opposite to the second axial side L2 connected to the rotor shaft 14, allowing it to rotate. The secondary shaft 40 of the reversing gear mechanism 4 is supported by the housing 2 via a pair of secondary bearings B4 disposed on both sides along the axial direction L of the reversing gear mechanism 4, allowing it to rotate. The differential housing 60 is supported by the housing 2 via differential bearings B6 that clamp the differential housing 60 and are arranged on both sides of the axial direction L, so that it can rotate.

[0025] Furthermore, the structure of the vehicle drive unit 1 (drive unit) is not limited to the form shown in the figure. For example, the vehicle drive unit 1 may also be a dual-shaft structure (folding dual-shaft structure) with the differential gear mechanism 6 arranged on the first shaft A1. Alternatively, the vehicle drive unit 1 may be a dual-shaft structure consisting of a planetary gear mechanism with the reducer arranged on the same shaft as the rotor 11. Alternatively, the vehicle drive unit 1 may be a single-shaft structure with the rotor 11, the reducer of the planetary gear mechanism, a bevel gear mechanism, or the differential gear mechanism 6 based on the planetary gear mechanism arranged on the same shaft. Alternatively, the vehicle drive unit 1 may be a four-shaft or more structure with the reducer arranged on two or more shafts. Alternatively, the vehicle drive unit 1 may be a device that transmits power from the rotary motor 10 to one wheel W without the differential gear mechanism 6. Furthermore, it does not preclude the vehicle drive unit 1 from having an internal combustion engine (not shown) that applies power to the rotary motor 10 when the rotary motor 10 functions as a generator. Furthermore, regardless of its form, the power transmission mechanism that transmits power between the rotary motor 10 and the wheel W can include various drive shafts and gears. Additionally, the power transmission mechanism can also include engaging components such as clutches and brakes.

[0026] However, sometimes eddy currents are generated on the stator 12 due to the rotating magnetic field generated by the flow of alternating current to the coil 13, for example, on the rotor 11 made of laminated electromagnetic steel plates and the metal rotor shaft 14. As a result, the rotor shaft 14 and the input shaft 15 connected to the rotor shaft 14 become charged. Lubricating oil is supplied to the bearings supporting the rotor shaft 14 and the input shaft 15, so that the rotor shaft 14 and the input shaft 15, the housing 2, and the bearings are insulated by an oil film, creating a potential difference between them. However, since the oil film is thin and not necessarily uniform, there will be places where the insulation is insufficient. Sometimes, at such places where the insulation is insufficient, electric spark discharges occur from the rotor shaft 14 and the input shaft 15 to the housing 2 and the bearings. Moreover, there is a concern that the bearings may deteriorate or electromagnetic noise may be released due to this electric spark discharge. Therefore, in this embodiment, a grounding component, i.e., an electrical connection component 3, is provided that contacts the input shaft 15 and is used to release eddy currents from the rotor shaft 14 and the input shaft 15 to the housing 2.

[0027] like Figure 2 As shown, the electrical connection component 3 is disposed on the first shaft A1 on the first axial side L1 of the input shaft 15. The electrical connection component 3 includes a housing 30, a brush 31, and a force-applying component 32. The brush 31 is formed of a conductive material such as carbon or silver. The housing 30 is fixed to the housing 2. The force-applying component 32 is disposed within the housing 30 and applies force to the brush 31 toward the second axial side L2 by means of a portion of the brush 31 (the end on the second axial side L2) protruding from the housing 30. As a result, the brush 31 contacts the end face 15t of the first axial side L1 of the input shaft 15. Since both the brush 31 and the input shaft 15 are disposed on the first shaft A1, the contact between the brush 31 and the input shaft 15 is maintained by sliding contact even when the input shaft 15 rotates.

[0028] The configuration is not limited to this form. For example, a brush that applies force to the axial first side L1 of the input shaft 15 can be provided at the end of the input shaft 15, and this brush contacts the inner wall of the housing 2 (the inner wall of the opposing wall portion 22 described later). That is, the electrical connection member 3 only needs to have a contact portion (contact, brush 31) that is electrically connected to the relatively rotating components (e.g., housing 2 and input shaft 15) through sliding contact. The brush 31 can be either a non-rotating or a rotating structure. Alternatively, a first component fixed to the housing 2 (and also fixed to the housing 30) and a second component fixed to the input shaft 15 (the object rotation axis) and rotating integrally with the input shaft 15 and rotatable relative to the housing 30 can be housed inside the housing 30, with the first and second components in sliding contact inside the housing 30. In this case, at least one of the first and second components is a contact (brush).

[0029] In this embodiment, the electrical connection member 3 electrically connects the housing 2 and the input shaft 15, which corresponds to the object rotation axis. However, the electrical connection member 3 can also be configured to electrically connect the housing 2 to the rotor shaft 14. In this case, the rotor shaft 14 corresponds to the object rotation axis. Additionally, sometimes eddy currents flow from the rotor shaft 14 to the secondary shaft 40 via the input shaft 15 through the meshing of metal gears. Therefore, this does not preclude the electrical connection member 3 from being configured to electrically connect the housing 2 and the secondary shaft 40. Moreover, in this case, the secondary shaft 40 corresponds to the object rotation axis.

[0030] If the rotating shaft of the object slides into contact with the brush 31, the brush 31 wears, generating wear powder. The brush 31 is made of a conductive material, and the wear powder is conductive. Therefore, there is a concern that the wear powder may cause electrical effects on the coil 13 wound on the stator 12, rotation sensors such as the resolver that detects the rotation of the rotor 11, etc. Furthermore, there is a concern that the bearing supporting the rotating shaft of the object, which is capable of rotating relative to the housing 2, may be damaged, causing mechanical effects. In this embodiment, the drive unit 1 of the vehicle is configured to reduce such effects of wear powder. Furthermore, the bearing that protects the object from the effects of wear powder is the bearing supporting the rotating shaft of the object, and is called the object bearing.

[0031] As in this embodiment, when the input shaft 15 corresponds to the object rotation shaft, the input bearing B2 corresponds to the object bearing. When the rotor shaft 14 corresponds to the object rotation shaft, the rotor bearing B1 located on the side closest to the housing 2 (in...) Figure 1 In the middle, the rotor bearing B1 on the second axial side L2 is equivalent to the object bearing. Additionally, when the secondary shaft 40 is equivalent to the object rotation axis, the secondary bearing B4 located on the side closest to the housing 2 (in...) Figure 1 In the middle, the secondary bearing B4 on the first axial side L1 is equivalent to the object bearing.

[0032] like Figure 2 As shown, the housing 2 includes a bearing support portion 21 that supports an input bearing B2 (the target bearing). The input shaft 15 is supported by the input bearing B2, so the input bearing B2 is arranged radially R between the bearing support portion 21 and the input shaft 15. Furthermore, the housing 2 includes a counter wall portion 22 disposed axially on a first side L1 closer to the bearing support portion 21 and opposite to the input bearing B2 from the first side L1. A target space E is formed between the end of the input shaft 15 on the first side L1, the input bearing B2, and the inner wall of the counter wall portion 22. The input bearing B2 is equivalent to the target bearing, so the target space E is the space between the counter wall portion 22 and the target bearing axially L. Additionally, the housing 2 includes a surrounding wall portion 23 that surrounds the target space E from the outer radial side R2. In other words, the target space E is formed as a space enclosed by the target bearing (here, the input bearing B2), the counter wall portion 22, and the surrounding wall portion 23.

[0033] Electrical connection component 3 is disposed between the end face 15t of input shaft 15 and the opposing wall portion 22, and is housed inside the object space E. Brush 31 is also disposed in the object space E. As described above, if the input shaft 15 and brush 31 slide in contact, brush 31 will wear, generating wear powder in the object space E. In this embodiment, as... Figures 2 to 4 As shown, in the vertical direction V under vehicle-mounted conditions, a recess 5 is provided at the lower part of the surrounding wall portion 23 located on the lower side V2, formed by partially recessing radially outward R2 from the inner surface 23a of the surrounding wall portion 23. Preferably, the recess 5 can be formed at the lowest part in the vertical direction V, but it is acceptable as long as it is generally formed at the periphery of the lowest part, within a range of approximately ±20 degrees upward from the lowest part. Wear powder mixed with lubricating oil introduced into the object space E moves downward in the object space E along with the oil and is captured by the recess 5. The captured wear powder is stored in the recess 5.

[0034] like Figure 2 As shown, the housing 2 has an oil inlet passage 26 for introducing oil into the object space E. Oil supplied by the lifting caused by gears such as the differential input gear 61 and by discharge through an oil pump (not shown) is introduced into the object space E through the inlet passage 26. While an example is shown with the inlet passage 26 formed in the bearing support portion 21 and the surrounding wall portion 23, this configuration is not limited to this. The gap between the input bearing B2 and the bearing support portion 21 can also be used as the inlet passage 26, or the inlet passage 26 can be formed in the opposing wall portion 22. The oil introduced into the object space E lubricates the input bearing B2 and flows out of the object space E. Before the oil reaches the input bearing B2, wear powder mixed in with the oil is captured by the recess 5, thus reducing the amount of wear powder mixed in with the oil and supplying oil to the input bearing B2.

[0035] like Figures 2 to 4 As shown, in this embodiment, the recess 5 is configured with a groove 51 extending along the axial direction L. Here, "extending along the axial direction L" means that the extension direction includes a component of the axial direction L. That is, the groove 51 can be formed to extend parallel to the axial direction L, or it can be formed to extend in a direction inclined relative to the axial direction L. Of course, the recess 5 may also be formed without such a groove 51. However, by having the groove 51, wear powder can be captured more efficiently.

[0036] In addition, such as Figures 2 to 4As shown, in this embodiment, the recess 5 further includes a recessed hole 52 extending radially outward from the bottom 53 of the groove 51 to the radially outer side R2. Here, the extending direction (hole extending direction) of the recessed hole 52 is inclined relative to the radial R, such that it advances towards the axial first side L1 as it moves radially outward R2. However, it is not limited to this structure; the extending direction of the recessed hole 52 may be parallel to the radial R or it may be inclined circumferentially relative to the radial R.

[0037] By accumulating the wear powder captured by the groove 51 in the recess 52, it is easy to prevent the captured wear powder from flowing out again, and it is also possible to continuously accumulate wear powder. Preferably, the volume of the recess 52 is the capacity to accumulate the wear powder generated throughout the entire product life of the vehicle drive unit 1, taking into account the usage period of the vehicle drive unit 1. That is, the volume of the recess 52 is larger than the assumed maximum amount of wear powder (the volume when it is accumulated), preferably about 1.5 to 3 times larger. The recess 52 can be formed, for example, by reprocessing the bottom 53 of the groove 51 using a drilling tool or the like. The volume of the recess 52 can be determined by the perforation depth during this reprocessing.

[0038] Furthermore, as described above, the recess 5 may be formed without the groove 51, and therefore, the recess 5 may also be formed without the recessed hole 52. Additionally, even when the groove 51 is present, the groove 51 may be formed without the recessed hole 52. Furthermore, in any case, it is preferable that the recess 5 as a whole can accumulate the amount of wear powder generated throughout the entire product life of the vehicle drive unit 1. For example, even without the groove 51 and the recessed hole 52, the volume of the recess 5 is larger than the assumed maximum amount of wear powder (the volume when accumulated), preferably by about 1.5 to 3 times.

[0039] In addition, in this embodiment, such as Figure 2 As shown, in the bottom 53 of the groove 51, the recess 52 is formed such that the area of ​​the opening portion of the recess 52 is smaller than the cross-sectional area of ​​the recess 52. Here, the cross-sectional area of ​​the recess 52 refers to the area of ​​a cross section orthogonal to the hole extension direction inside the recess 52. When the recess 52 is formed by reprocessing the bottom 53 of the groove 51 using a drilling tool or the like, the area of ​​the opening portion of the recess 52 in the groove 51 is approximately the same as the cross-sectional area of ​​the recess 52. In this embodiment, by blocking a portion of the opening portion by the input bearing B2 (by the outer ring of the input bearing B2), the area of ​​the opening portion of the recess 52 at the bottom 53 is made smaller relative to the opening area of ​​the recess 52 itself.

[0040] Of course, the recess 52 can also be formed by methods other than reprocessing using a drilling tool. For example, the recess 52 can be formed when the housing 2 is formed by casting or the like. Moreover, if the area of ​​the opening at the bottom 53 is larger than the internal cross-sectional area when the recess 52 is formed, the opening does not need to be blocked by the outer ring of the bearing or the like.

[0041] In addition, in this embodiment, such as Figure 2 As shown, the bearing support portion 21 includes a first support surface 27 that supports the input bearing B2 from the radially outer side R2, and a second support surface 28 that supports the input bearing B2 from the axially first side L1. The object space E is the space between the opposing wall portion 22 and the input bearing B2 along the axial direction L, so it can be referred to as the space between the opposing wall portion 22 and the second support surface 28 along the axial direction L1. Therefore, the end face of the surrounding wall portion 23, which surrounds the object space E from the radially outer side R2, can function as the second support surface 28. Therefore, it can be said that the surrounding wall portion 23 is formed by the portion of the housing 2 located on the axially first side L1 relative to the second support surface 28 and forming the second support surface 28.

[0042] In this embodiment, the aforementioned recess 52 is formed as an opening at the corner where the first support surface 27 and the second support surface 28 intersect, and at least a portion of the opening in the inner surface 23a of the surrounding wall portion 23, which is continuous with the second support surface 28 and extends axially to the first side L1. By supporting the input bearing B2 with the first support surface 27 and the second support surface 28, at least a portion of the opening in the first support surface 27 and the opening in the second support surface 28 is blocked, thereby reducing the area of ​​the opening in the bottom 53 of the recess 52 relative to the opening area of ​​the recess 52 itself. Furthermore, even if the opening in the first support surface 27 and the opening in the second support surface 28 are completely blocked by supporting the input bearing B2 with the first support surface 27 and the second support surface 28, the opening in the inner surface 23a of the surrounding wall portion 23 is not blocked, so there is no problem. In addition, as Figure 2 As shown, the opening of the first support surface 27 is highly likely to be completely blocked, so the recess 52 may not need to open on the first support surface 27. That is, preferably, the recess 5 has a recess 52 that opens on both the inner surface 23a surrounding the wall portion 23 and the second support surface 28, and extends radially outward R2 from the bottom 53 of the groove 51, and extends in a direction inclined relative to the second support surface 28. In addition, since the first support surface 27 and the second support surface 28 are orthogonal, the recess 52 extends in a direction that is also inclined relative to the first support surface 27.

[0043] Furthermore, in this embodiment, as described above, the recess 52 is formed as a corner opening where the first support surface 27 and the second support surface 28 intersect. When the recess 52 is formed by re-processing the bottom 53 of the groove 51 using a drill or the like, the tool is unlikely to come into contact with the first support surface 27 and the second support surface 28 during processing, so the processing of the recess 52 can be performed easily.

[0044] In addition, such as Figure 2 As shown, in this embodiment, the axial L-shaped arrangement area of ​​the recess 5 (groove 51, recess 52) overlaps with the axial L-shaped arrangement area of ​​the electrical connection member 3 (in particular, the portion where the brush 31 contacts the input shaft 15). That is, the recess 5 and the electrical connection member 3 overlap when viewed radially. Therefore, the diffusion of wear powder into the housing 2 can be suppressed without increasing the axial L-shaped dimension of the vehicle drive unit 1.

[0045] As explained above, according to this embodiment, wear powder can be accumulated in the recess 5, reducing the possibility of wear powder movement affecting the bearing or other components. The recess 5 for accumulating wear powder has a simple structure, thus easily preventing the vehicle drive unit 1 and the rotary motor 10 from becoming too large. In other words, according to this embodiment, the large size of the drive unit can be suppressed, and the diffusion of wear powder generated by the electrical connection member 3 into the housing 2 can be suppressed.

[0046] The following is for reference Figures 5 to 9 The vehicle drive device 1 of the comparative example to the vehicle drive device 1 of this embodiment will be described. Figures 5 to 9 Is with Figure 2 Enlarged sectional view of the corresponding section.

[0047] Figure 5 An example of a vehicle drive unit 1 from the first comparative example is shown. For example... Figure 5 As shown, in the first comparative example of the vehicle drive unit 1, the path of oil flowing from the object space E to the input bearing B2 is restricted by the shim member 7. The oil flowing from the object space E to the input bearing B2 is supplied through a gap G located radially inward relative to the shim member 7 on the inner side R1. This gap G is located on the lower side V2 of the first shaft A1, above the object space E and the input bearing B2 on the upper side V1. Since most of the wear powder deposited in the oil is located on the lower side V2, it is possible to suppress wear powder reaching the input bearing B2 through the gap G. However, in this case, it is important to note the increased component cost due to the addition of the shim member 7, and the increased axial length L of the vehicle drive unit 1 due to the placement of the shim member 7.

[0048] Figure 6 An example of a vehicle drive unit 1 from the second comparative example is shown. For example... Figure 6As shown, in the vehicle drive unit 1 of the second comparative example, a cylindrical flange portion 15f is formed at the end of the input shaft 15 on the first axial side L1, protruding radially outward R2 towards the first axial side L1. A brush 31 is disposed on the radially inner side R1 of the flange portion 15f. A groove 15m is formed on the radially inner side R1 of the flange portion 15f, i.e., the inner surface 15a, recessing radially outward R2 from the inner surface 15a. The brush 31 slides in contact with the end face 15t of the input shaft 15 on the second axial side L2 relative to the groove 15m. Wear particles generated due to the sliding contact are captured by the groove 15m. Figure 2 and Figure 6 The comparison shows that the point to note is that when the groove is set to 15m, the dimension of the input shaft 15 on the first axial side L1 of the input shaft 15 at the end face 15t of the input shaft 15 becomes longer, and the axial length of the vehicle drive device 1 is likely to increase.

[0049] Figure 7 An example of a vehicle drive unit 1 from the third comparative example is shown. For example... Figure 7 As shown, in the third comparative example of the vehicle drive unit 1, in the vehicle-mounted state, an oil discharge passage 29 is provided at the lower V2 position to allow oil to flow out from the target space E. By allowing oil mixed with wear particles to flow out of the target space E quickly through the oil discharge passage 29, the amount of oil containing wear particles flowing into the input bearing B2 is reduced. In the third comparative example, it should be noted that compared with the case where the oil discharge passage 29 is not provided, the amount of oil supplied to the input bearing B2 is reduced, which may increase the amount of oil circulating in the vehicle drive unit 1 per unit time. In addition, it should also be noted that although the wear particles contained in the oil can be removed by passing through an oil filter or the like in the oil circulation path, although the concentration of wear particles is reduced by diffusion in the path from the target space E to the oil filter, there is still a possibility that the wear particles may affect other parts.

[0050] Figure 8 An example of the vehicle drive unit 1 of the fourth comparative example is shown. For example... Figure 8 As shown, in the fourth comparative example of the vehicle drive unit 1, the input bearing B2 is a sealed bearing in which steel balls (rolling parts) are sealed inside the raceway component by a sealing member F. For the lubrication of the bearing itself, lubricating material is also sealed inside the raceway component. Because the input bearing B2 is sealed, the influence of oil containing wear particles can be eliminated. In this case, attention should be paid to the increased component cost due to the use of a sealed bearing, and the durability of the sealed bearing (especially the sealing member F) in oil.

[0051] Figure 9 An example of the fifth comparative example, the vehicle drive unit 1, is shown. For example... Figure 9As shown, in the fifth comparative example of the vehicle drive unit 1, the flow of oil between the object space E and the bearing mounting space E2 where the input bearing B2 is mounted is blocked by the sealing member S. The bearing is not lubricated by oil containing wear particles, thus reducing the impact of wear particles on the bearing. However, in this case, it is important to note the increased component cost due to the addition of the sealing member S, and the increased size of the vehicle drive unit 1 due to the increased axial dimension L required to accommodate the sealing member S and the bearing mounting space E2.

[0052] The following is a brief summary of the embodiments of the drive device 1 described above.

[0053] In one embodiment, the drive device 1 includes: a rotor 11; a stator 12 having coils 13; an object rotation shaft 15 that transmits the rotation of the rotor 11; a housing 2 that houses the rotor 11, the stator 12, and the object rotation shaft 15; an object bearing B2 that supports the object rotation shaft 15 so that it can rotate relative to the housing 2; and an electrical connection member 3 that electrically connects the object rotation shaft 15 and the housing 2. The drive device 1 defines the direction along the rotation axis A1 of the object rotation shaft 15 as axial L, the direction orthogonal to the rotation axis A1 as radial R, and one side of the axial L as the first axial side L1. The housing 2 includes: a bearing support portion 2. 1. It supports the object bearing B2; opposing wall 22, which is disposed on the first axial side L1 of the bearing support 21 and opposite to the object bearing B2 from the first axial side L1; and surrounding wall 23, which surrounds the space between the opposing wall 22 and the object bearing B2 in the axial direction L from the outer side R2 of the radial direction R, i.e., the object space E. The electrical connection member 3 has a contact portion 31 that allows relatively rotating components to be electrically connected to each other by sliding contact. The contact portion 31 is disposed in the object space E. A recess 5 is provided in the lower part V2 of the surrounding wall 23 in a manner that is recessed from the inner surface 23a of the surrounding wall 23 to the outer side R2 of the radial direction R.

[0054] According to this structure, when wear powder is generated due to the sliding contact of the electrical connection member 3, the wear powder can be accumulated in the recess 5. This reduces the possibility of wear powder moving from the contact portion 31 and affecting the bearing B2 or other components. The recess 5 for accumulating wear powder has a simple structure formed by recessing into the lower portion V2 of the inner surface 23a surrounding the wall portion 23, thus easily preventing the drive unit 1 from becoming too large. In other words, according to this structure, the large size of the drive unit 1 can be suppressed, and the diffusion of wear powder generated by the electrical connection member 3 into the housing 2 can be suppressed.

[0055] In addition, the preferred drive device 1 has an inlet passage 26 that introduces oil into the object space E. The oil introduced into the object space E through the inlet passage 26 flows out of the object space E through the object bearing B2. The recess 5 has a groove 51 extending along the axial direction L.

[0056] According to this structure, when the oil introduced into the object space E flows along the inner surface 23a of the surrounding wall 23 and is guided towards the object bearing B2, wear powder is easily trapped in the groove 51. Therefore, wear powder contained in the oil is easily accumulated in the groove 5.

[0057] In addition, the drive device 1 preferably includes a recess 5 with a recess 52 that extends from the bottom 53 of the groove 51 toward the outer side R2 of the radial R.

[0058] According to this structure, the wear powder entering the groove 51 further enters the recess 52, and the wear powder is not easy to leak out from the recess 5, so that more wear powder can be accumulated in the recess 5.

[0059] Furthermore, the drive device 1 preferably includes a bearing support portion 21 comprising a first support surface 27 supporting the target bearing B2 from the outer side R2 of the radial R, and a second support surface 28 supporting the target bearing B2 from the first axial side L1. The surrounding wall portion 23 is formed by a portion of the housing 2 located on the first axial side L1 relative to the second support surface 28 and forming the second support surface 28. The recess 5 comprises a recess 52 that opens to both the inner surface 23a of the surrounding wall portion 23 and the second support surface 28 and extends in a direction inclined relative to the second support surface 28.

[0060] According to this structure, the object bearing B2, supported by the second support surface 28, can block a portion of the opening in the recess 52 on the second support surface 28. This allows for a simple shape to be formed in the recess 52, and makes the area of ​​the opening of the recess 52 smaller than the cross-sectional area of ​​the interior of the recess 52. By forming the recess 52 into such a shape (bottleneck shape), it becomes difficult for wear powder that has entered the recess 52 to exit.

Claims

1. A drive device comprising: a rotor; a stator including a coil; an object rotating shaft that transmits rotation of the rotor; a housing that accommodates the rotor, the stator, and the object rotating shaft; an object bearing that supports the object rotating shaft so as to be rotatable with respect to the housing; and an electrical connection member that electrically connects the object rotating shaft and the housing, the drive device being characterized in that: a direction along an axis of rotation of the object rotating shaft is defined as an axial direction, a direction orthogonal to the axis of rotation is defined as a radial direction, and one side of the axial direction is defined as an axial direction first side, the housing includes: a bearing support portion that supports the object bearing; an opposing wall portion that is disposed on the axial direction first side of the bearing support portion and opposes the object bearing from the axial direction first side; and a surrounding wall portion that surrounds a space between the opposing wall portion and the object bearing in the axial direction from the outside in the radial direction, the electrical connection member includes a contact portion that electrically connects members that relatively rotate to each other by sliding contact, the contact portion is disposed in the object space, and a recess portion is provided in a lower portion of the surrounding wall portion and is formed so as to be recessed from an inner surface of the surrounding wall portion toward the outside in the radial direction.

2. The drive device according to claim 1, characterized in that: an introduction passage that introduces oil into the object space is provided, oil introduced from the introduction passage into the object space flows out from the object space through the object bearing, and the recess portion includes a groove that extends in the axial direction.

3. The drive device according to claim 2, characterized in that: the recess portion includes a bore that extends from a bottom of the groove toward the outside in the radial direction.

4. The drive device according to any one of claims 1 to 3, characterized in that: the bearing support portion includes a first support surface that supports the object bearing from the outside in the radial direction and a second support surface that supports the object bearing from the axial direction first side, the surrounding wall portion is formed by a portion of the housing that is located on the axial direction first side with respect to the second support surface and forms the second support surface, and the recess portion includes a bore that is open to both the inner surface of the surrounding wall portion and the second support surface and extends in a direction inclined with respect to the second support surface. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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