Drive device, vehicle

Abstract

A drive device, a vehicle are provided. The drive device includes a first bearing lubricated by a fluid and a second bearing lubricated by a lubricating material having higher electric conductivity than the fluid. The first bearing rotatably supports a shaft extending in an axial direction along a rotational axis. A housing of the drive device has a first bearing seat that holds the first bearing. The second bearing is provided between the shaft and the housing to rotatably support the shaft. The second bearing is disposed in a space that is isolated from the first bearing seat.

Description

Technical Field

[0001] This invention relates to a drive device and a vehicle. Background Technology

[0002] Conventionally, drive devices with a current-removing mechanism on the shaft of the motor are known. For example, the rotating shaft of a rotary electric machine is supported by a main bearing and an auxiliary bearing. Conductive grease is sealed in the auxiliary bearing. As a result, when the shaft voltage of the rotating shaft needs to rise, the charge flows through the conductive grease of the auxiliary bearing to the outer frame, but does not flow to the main bearing (see, for example, Japanese Patent Application Publication No. 2000-316251).

[0003] [Existing Technical Documents]

[0004] [Patent Literature]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2000-316251 Summary of the Invention

[0006] However, when foreign matter adheres to a bearing like the one described above, it may be difficult for electrical charge to flow to the housing, such as the outer frame. For example, in a vehicle motor, lubricating oil and refrigerant used to cool the motor circulate. If these substances adhere to a bearing containing such lubricating materials, they may mix with the lubricating materials, increasing the resistance of the lubricating materials. Therefore, it may be difficult to maintain good electrical conductivity between the shaft and the housing.

[0007] The purpose of this invention is to maintain good electrical conductivity between the shaft and the housing.

[0008] An exemplary drive device of the present invention includes a shaft, a rotor, a stator, a first bearing, a housing, and a second bearing. The shaft extends axially along a rotation axis. The rotor is fixed to the shaft and rotatable about the rotation axis. The stator is radially spaced from the rotor. The first bearing rotatably supports the shaft and is lubricated by a fluid. The housing has a first bearing seat for holding the first bearing and houses the rotor and the stator. The second bearing is disposed between the shaft and the housing and rotatably supports the shaft, and is lubricated by a lubricating material with a conductivity higher than that of the fluid. The second bearing is disposed in a space isolated from the first bearing seat.

[0009] An exemplary vehicle of the present invention includes the above-described drive unit.

[0010] According to the exemplary drive device and vehicle of the present invention, the electrical conductivity between the shaft and the housing can be well maintained. Attached Figure Description

[0011] Figure 1This is a conceptual diagram showing an example of the structure of a drive device.

[0012] Figure 2 This is a conceptual diagram illustrating an example of the shaft de-energization structure of the drive device according to an embodiment.

[0013] Figure 3 This is a schematic diagram showing an example of a vehicle equipped with a drive unit.

[0014] Figure 4 This is a conceptual diagram illustrating an example of the shaft de-energization structure of the drive device in the first modified example.

[0015] Figure 5 This is a conceptual diagram illustrating another example of the shaft de-energizing structure of the drive device in the first modified example.

[0016] Figure 6 This is a conceptual diagram illustrating an example of the shaft de-energization structure of the drive device in the second modified example.

[0017] [Symbol Explanation]

[0018] 100…Drive unit, 200…Battery, 300…Vehicle, 1…Axle, 101…First axle through hole, 102…Second axle through hole, 11…Axle cylinder, 111…Inlet, 12…Hollow section, 13…Axle wall section, 14…Axle recess, 15…Second columnar section, 2…Motor section, 21…Rotor, 211…Rotor core, 2111…Rotor through hole, 212…Magnet, 22…Stator, 221…Stator core, 222…Coil section, 2221…Coil edge, 3…Gear section, 31…Reduction gear, 311…Main drive gear, 312…Intermediate… Drive gear, 313…end drive gear, 314…intermediate shaft, 32…differential device, 321…gear ring, 4…housing, 401…motor storage space, 402…gear storage space, 403…space, 41…first housing cylindrical part, 42…side plate part, 4201…side plate through hole, 4202…first drive shaft through hole, 421…first motor bearing housing, 4211…first motor bearing, 422…second motor bearing housing, 4221…second motor bearing, 423…first intermediate bearing housing, 4231…first intermediate bearing, 424…first output bearing housing. 4241…First output bearing, 43…Housing cover, 431…Third motor bearing housing, 4311…Third motor bearing, 4312…Opening, 432…Detector housing, 443…Conducting bearing housing, 4331…Conducting bearing, 4332…Lubricating material, 44…Cover component, 441…Plate, 442…First columnar part, 443…Conducting bearing housing, 4431…Conducting bearing, 4432…Lubricating material, 45…Second housing cylindrical part, 46…Gear cover, 460…Second drive shaft through hole, 461…Fourth motor bearing housing, 4611…Fourth motor Bearing, 462…Second intermediate bearing housing, 4621…Second intermediate bearing, 463…Second output bearing housing, 4631…Second output bearing, 464…Packet section, 465…Flow path, 5…Liquid circulation section, 51…Piping section, 52…Pump, 53…Cooler unit, 54…Fluid storage tank, 6…Conducting bearing, 61…Lubricating material, 7…Rotation detector, 81…First sealing component, 82…Second sealing component, F…Fluid, P…Liquid storage section, Ds, Ds1, Ds2…Drive shaft, J1…Rotation axis, J2…Intermediate axis, J3…Drive axis. Detailed Implementation

[0019] Exemplary embodiments will now be described with reference to the accompanying drawings.

[0020] In this specification, the direction parallel to the rotation axis J1 of the motor unit 2 is referred to as the "axial direction" of the drive device 100. Regarding the axial direction, as follows... Figure 1As shown, the motor part 2 side is designated as the axial side D1 side, and the gear part 3 side is designated as the axial side D2 side. In addition, the radial direction orthogonal to the rotation axis J1 and other specified axes is called "radial direction", and the circumferential direction centered on the rotation axis J1 and other specified axes is called "circumferential direction".

[0021] Furthermore, in this specification, in the positional relationship between any of the orientations, lines, and planes and any other, "parallel" includes not only a state where the two never intersect regardless of their extension, but also a state where they are substantially parallel. Similarly, "perpendicular" includes not only a state where the two intersect at 90 degrees, but also a state where they are substantially perpendicular. That is, "parallel" and "perpendicular" respectively include states where the positional relationship between the two exhibits an angular deviation to a degree that does not depart from the spirit of the invention.

[0022] Furthermore, in this specification, "extending in a specified direction" includes not only structures whose extension direction strictly follows the specified direction, but also structures that substantially extend in the specified direction. That is, "extending in a specified direction" includes structures that deviate directionally from the specified direction to a degree that does not depart from the spirit of the invention. The same applies to "extending in a specified direction."

[0023] <1. Implementation Method>

[0024] Figure 1 This is a conceptual diagram showing a structural example of the drive device 100. Figure 2 This is a conceptual diagram illustrating an example of the shaft de-energizing structure of the drive device 100 according to an embodiment. Figure 3 This is a schematic diagram showing an example of a vehicle 300 equipped with a drive unit 100. Additionally, Figure 1 and Figure 2 This is just a concept drawing; the configuration and dimensions of each part are not necessarily identical to the actual drive unit 100. Furthermore, Figure 2 It is Figure 1 The enlarged image shows part A enclosed by the dashed line. Figure 3 The concept also shows vehicle 300.

[0025] In this embodiment, such as Figure 3 As shown, the drive unit 100 is installed in a vehicle 300, such as a hybrid electric vehicle (HV), a plug-in hybrid electric vehicle (PHV), or an electric vehicle (EV), which uses at least a motor as its power source. The drive unit 100 serves as the power source for the aforementioned vehicle 300. The vehicle 300 has the drive unit 100. By installing the drive unit 100, the drive unit 100 of the vehicle 300, including the electrostatic discharge mechanism between the shaft 1 and the housing 4, can be miniaturized. Figure 3In this vehicle, drive unit 100 drives the front wheels of vehicle 300. Furthermore, drive unit 100 only needs to drive at least one wheel. Additionally, vehicle 300 also has a battery 200. Battery 200 stores electricity for supplying to drive unit 100.

[0026] like Figure 1 As shown, the drive device 100 includes: a shaft 1, a motor part 2, a gear part 3, a housing 4, a liquid circulation part 5, a conductive bearing 6, a rotation detector 7, a first sealing component 81, and a second sealing component 82.

[0027] <1-1. Axis 1>

[0028] Shaft 1 extends axially along the rotation axis J1. As described above, the drive device 100 includes shaft 1. Shaft 1 is rotatable about the rotation axis J1. Figure 1 As shown, shaft 1 is supported by housing 4 and is rotatable via a first motor bearing 4211, a second motor bearing 4221, a third motor bearing 4311, and a fourth motor bearing 4611 (described later). That is, drive unit 100 includes these bearings 4211, 4221, 4311, and 4611. These bearings 4211, 4221, 4311, and 4611 rotatably support shaft 1.

[0029] Shaft 1 is a cylindrical shape extending axially. Fluid F flows inside shaft 1. The drive unit 100 also includes the aforementioned fluid F. In this embodiment, fluid F is a lubricant used to lubricate the gear unit 3 and the bearings of the drive unit 100, such as ATF (automatic transmission fluid). Fluid F is also used as a refrigerant to cool the motor unit 2, etc. Depending on the rotation of shaft 1, fluid F flowing inside shaft 1 can be supplied to the motor unit 2, the first motor bearing 4211, and the third motor bearing 4311, etc., through the first shaft through hole 101 described later. Therefore, fluid F can cool the stator 22 (especially the coil edge 2221 described later) and the aforementioned bearings 4211, 4311, etc.

[0030] Alternatively, shaft 1 can be split at the middle of its axial direction. When shaft 1 can be split, the split shafts can be connected, for example, by spline engagement. Alternatively, they can be connected using a threaded coupling with male and female threads, or by pressing or welding. When using pressing or welding, a combination of serrated recesses and protrusions extending axially can be employed. This structure allows for reliable transmission of rotation.

[0031] <1-1-1. Shaft cylindrical section 11 and hollow section 12>

[0032] Shaft 1 has a cylindrical shaft section 11 surrounding a rotation axis J1. The shaft section 11 is cylindrical and extends axially along the rotation axis J1. The shaft section 11 is rotatably supported by a third motor bearing 4311. Additionally, the shaft section 11 is also rotatably supported by a first motor bearing 4211, a second motor bearing 4221, a fourth motor bearing 4611, and a conductive bearing 6. The shaft section 11 is conductive and, in this embodiment, is made of metal. Furthermore, shaft 1 has a hollow section 12 and an inlet 111. The hollow section 12 is a space surrounded by the inner circumferential surface of the shaft section 11 and is disposed inside the shaft section 11. The inlet 111 is the other axial end of the cylindrical shaft section 11 and is connected to the flow path 465 of the gear cover section 46 (described later). Fluid F flows into the hollow section 12 from the flow path 465 via the inlet 111.

[0033] <1-1-2. Shaft Wall Part 13>

[0034] Shaft 1 also includes a shaft wall portion 13. The shaft wall portion 13 is disposed inside the shaft cylinder portion 11 and extends radially. The shaft wall portion 13 is disposed on one axial side (D1) of the shaft cylinder portion 11. Furthermore, in this embodiment, the other axial end of the shaft wall portion 13 is disposed at a position D2 further axially than the rotation detector 7. The radially outer end of the shaft wall portion 13 is connected to the inner surface of the shaft cylinder portion 11. Preferably, the shaft wall portion 13 and the shaft cylinder portion 11 are integral. For example, in this embodiment, the shaft wall portion 13 is a different part from the same component as the shaft cylinder portion 11. By forming the shaft wall portion 13 integrally with the shaft cylinder portion 11, shaft 1 can be easily manufactured. Furthermore, the number of components in shaft 1 can be reduced, thus facilitating the assembly of the drive device 100. However, this is not limited to this example; the shaft wall portion 13 may also be a different part from the shaft cylinder portion 11.

[0035] At one axial end of shaft 1, shaft wall portion 13 and shaft sleeve portion 11 together form shaft recess 14. That is, shaft 1 has shaft recess 14. Shaft recess 14 is recessed from one axial end of shaft 1 toward the other axial end D2. In this embodiment, shaft recess 14 receives at least the other axial side D2 of the first columnar portion 442. Furthermore, shaft recess 14 receives conductive bearing 6 and first seal 81.

[0036] <1-1-3. First shaft through hole 101>

[0037] A first shaft through hole 101 is provided on the shaft sleeve portion 11. That is, the shaft 1 also has a first shaft through hole 101 that penetrates the shaft sleeve portion 11 radially. The number of first shaft through holes 101 can be one or more. When the shaft 1 rotates, the fluid F inside the shaft sleeve portion 11 flows out from the hollow portion 12 to the outside of the shaft sleeve portion 11 through the first shaft through hole 101 due to centrifugal force. In this embodiment, as... Figure 1As shown, the first shaft through hole 101 is positioned at a position D1 further axially than one end of the rotor 21 and D2 further axially than one end of the rotor 21, and is connected to the rotor through hole 2111 described later. However, it is not limited to... Figure 1 For example, the first shaft through hole 101 can also be positioned at a location axially opposite to the other end of the rotor 21 (D2 axially) and axially opposite to the first motor bearing 4211 (D1 axially), or at a location axially opposite to the other end of the rotor 21 (D1 axially) and axially opposite to the third motor bearing 4311 (D2 axially). That is, at least a portion of the first shaft through hole 101 can be positioned at at least one of these locations. Furthermore, the above examples do not preclude the possibility of omitting the structure of the first shaft through hole 101 and the rotor through hole 2111.

[0038] <1-1-4. Second shaft through hole 102>

[0039] A second shaft through hole 102 is provided on the shaft sleeve portion 11. The shaft 1 also has a second shaft through hole 102. The second shaft through hole 102 penetrates the shaft sleeve portion 11 radially. Alternatively, the second shaft through hole 102 may also penetrate the shaft sleeve portion 11 in a direction intersecting the radial and axial directions. In addition, the second shaft through hole 102 is an example of the "shaft through hole" of the present invention.

[0040] The number of second through holes 102 can be one or more. In the latter case, the second through holes 102 can be arranged at equal or different intervals in the circumferential direction. In addition, the above example does not exclude the structure in which the second through holes 102 are omitted.

[0041] In this embodiment, the second shaft through hole 102 is positioned axially one D1 away from the first shaft through hole 101 (see reference). Figure 1 The radially outer end of the second shaft through-hole 102 is connected to the third motor bearing housing 431. The radially inner end of the second shaft through-hole 102 is located at a position D2 axially opposite to the shaft wall portion 13 and is connected to the hollow portion 12. Here, fluid F can flow inside the shaft cylinder portion 11. This fluid F is also supplied to the third motor bearing 4311 through the second shaft through-hole 102. For example, when the shaft 1 rotates, the fluid F flowing inside the shaft cylinder portion 11 flows into the second shaft through-hole 102 due to centrifugal force. Therefore, even without an EOP (electric oil pump), for example, fluid F can flow out from the second shaft through-hole 102 to the outside of the shaft 1. At least a portion of the outflowing fluid F can be supplied to the third motor bearing 4311.

[0042] Furthermore, in this embodiment, the other axial end of the shaft wall portion 13 is positioned axially further D2 than the other axial end of the opening 4312 of the third motor bearing housing 431 (described later). Alternatively, the other axial end of the shaft wall portion 13 may be located at the same axial position as the other axial end of the opening 4312. This allows for a narrower axial distance between the radially inner end of the second shaft through hole 102 and the shaft wall portion 13. Therefore, for example, fluid F flowing axially towards D1 within the shaft sleeve portion 11 can easily flow into the second shaft through hole 102, and less fluid F remains between the radially inner end of the second shaft through hole 102 and the shaft wall portion 13. Consequently, fluid F within the shaft sleeve portion 11 can be supplied to the third motor bearing 4311 more smoothly. However, the above example does not preclude a structure in which the other axial end of the shaft wall portion 13 is positioned axially further D1 than the other axial end of the opening 4312.

[0043] The radially outer end of the second shaft through hole 102 is positioned at a position D1 axially closer to the third motor bearing 4311. Preferably, the radially outer end of the second shaft through hole 102 is positioned at a position D2 axially closer to the other end of the opening 4312 of the housing cover 43 (described later). More preferably, the radially outer end of the second shaft through hole 102 is positioned D2 axially away from the second sealing member 82. Here, as described above, the radially outer end of the second shaft through hole 102 is connected to the interior of the third motor bearing housing 431. Therefore, compared to the structure where the radially outer end of the second shaft through hole 102 is positioned D1 axially closer to the other end of the opening 4312 (i.e., the radially outer end of the second shaft through hole 102 is connected to the exterior of the third motor bearing housing 431), fluid F is less likely to intrude into the space 403 (described later) where the shaft sleeve portion 11 is located axially. Therefore, fluid F can be suppressed from acting on the rotation detector 7 and the conductive bearing 6 within the shaft recess 14. Furthermore, the above examples do not exclude the structure in which the radially outer end of the second shaft through hole 102 is positioned on the axial side D1 relative to the axial side end of the opening 4312, nor do they exclude the structure in which it is positioned on the axial side D1 relative to the second sealing member 82.

[0044] <1-2. Motor Section 2>

[0045] Motor 2 is a DC brushless motor. Motor 2 is the drive source for drive unit 100, driven by electricity from an inverter (not shown). Motor 2 is an inner rotor type with a rotor 21 rotatably arranged inside the stator 22. Figure 1 As shown, the motor unit 2 has a rotor 21 and a stator 22.

[0046] <1-2-1. Rotor 21>

[0047] Rotor 21 is supported on shaft 1. The drive unit 100 includes rotor 21. Rotor 21 is fixed to shaft 1 and can rotate about a rotation axis J1. Rotor 21 rotates by supplying power to stator 22 from a power source (not shown) of the drive unit 100. Rotor 21 has a rotor core 211 and magnets 212. Rotor core 211 is formed, for example, by stacking thin sheet-like electromagnetic steel plates. Rotor core 211 is an axially extending cylinder fixed to the radially outer surface of shaft 1. A plurality of magnets 212 are fixed to rotor core 211. The magnetic poles of the plurality of magnets 212 are arranged alternately circumferentially.

[0048] Furthermore, the rotor core 211 has a rotor through-hole 2111. The rotor through-hole 2111 extends axially through the rotor core 211 and is connected to the first shaft through-hole 101. The rotor through-hole 2111 serves as a flow path for the fluid F, which also functions as a refrigerant. When the rotor 21 rotates, the fluid F flowing in the hollow portion 12 of the shaft 1 can flow into the rotor through-hole 2111 via the first shaft through-hole 101. In addition, the fluid F flowing into the rotor through-hole 2111 can flow outward from both axial ends of the rotor through-hole 2111. The outflowing fluid F flies toward the stator 22, for example, cooling the coil portion 222 (especially the coil end 2221). In addition, the outflowing fluid F is dispersed toward the first motor bearing 4211 and the third motor bearing 4311, which rotatably support the shaft 1, lubricating and cooling these bearings 4211 and 4311.

[0049] <1-2-2. Stator 22>

[0050] The stator 22 is radially spaced from the rotor 21. The drive unit 100 includes the stator 22. The stator 22 is positioned radially outward from the rotor 21. The stator 22 has a stator core 221 and a coil portion 222. The stator 22 is held by a first housing cylinder 41, described later. The stator core 221 has a plurality of magnetic pole teeth (not shown) extending radially inward from the inner circumference of the annular magnetic yoke. The coil portion 222 is formed by winding a wire around the magnetic pole teeth through an insulator (not shown). The coil portion 222 has a coil end 2221 protruding from the axial end face of the stator core 221.

[0051] <1-3. Gear Section 3>

[0052] Next, the gear unit 3 is a power transmission device that transmits the power of the motor unit 2 to the drive shaft Ds, which will be described later. The gear unit 3 includes a reduction gear 31 and a differential gear 32.

[0053] <1-3-1. Speed ​​Reduction Device 31>

[0054] The reduction gear 31 is connected to the shaft 1. The reduction gear 31 has the function of reducing the rotational speed of the motor 2, thereby increasing the torque output from the motor 2 and the reduction ratio accordingly. The reduction gear 31 transmits the torque output from the motor 2 to the differential gear 32. That is, the gear 3 is connected to one axial side (D1) of the shaft 1, which rotates around a horizontally extending axis of rotation (J1).

[0055] The reduction gear 31 has a main drive gear 311, an intermediate driven gear 312, a final drive gear 313, and an intermediate shaft 314. The torque output from the motor unit 2 is transmitted to the gear ring 321 of the differential device 32 via the shaft 1, the main drive gear 311, the intermediate driven gear 312, the intermediate shaft 314, and the final drive gear 313.

[0056] The main drive gear 311 is disposed on the outer circumferential surface of the shaft 1. The main drive gear 311 can be the same component as the shaft 1, or it can be a separate component that is securely fixed. The main drive gear 311 rotates together with the shaft 1 around the rotation axis J1.

[0057] The intermediate shaft 314 extends along an intermediate axis J2 parallel to the rotation axis J1. The two ends of the intermediate shaft 314 are supported by a first intermediate bearing 4231 and a second intermediate bearing 4621, enabling it to rotate about the intermediate axis J2. An intermediate driven gear 312 and a final drive gear 313 are disposed on the outer circumferential surface of the intermediate shaft 314. The intermediate driven gear 312 can be the same component as the intermediate shaft 314, or it can be a separate component that is securely fixed.

[0058] The intermediate driven gear 312 and the final drive gear 313 rotate integrally with the intermediate shaft 314 around the intermediate axis J2. The intermediate driven gear 312 meshes with the main drive gear 311. The final drive gear 313 meshes with the gear ring 321 of the differential device 32.

[0059] The torque of shaft 1 is transmitted from the main drive gear 311 to the intermediate driven gear 312. The torque transmitted to the intermediate driven gear 312 is transmitted to the final drive gear 313 via the intermediate shaft 314. In addition, the torque is transmitted from the final drive gear 313 to the gear ring 321.

[0060] <1-3-2. Differential Device 32>

[0061] A differential 32 is mounted on the drive shaft Ds. The differential 32 has a gear ring 321. The gear ring 321 transmits the torque from the reduction gear 31 to the drive shaft Ds. The drive shafts Ds are mounted on the opposite side of the differential 32 (D2) and on one side (D1). The drive shaft Ds1 on the side of axial direction D1 is rotatably supported by a first output bearing 4241 (described later). The drive shaft Ds2 on the opposite side of the differential 32 is rotatably supported by a second output bearing 4631 (described later). For example, when the vehicle is turning, the differential 32 absorbs the speed difference between the drive shafts Ds1 and Ds2 on both sides of the axial direction and transmits torque to them.

[0062] The lower end of the gear ring 321 is disposed inside the liquid storage section P (described later) for the accumulation of fluid F stored in the lower part of the gear section receiving space 402 (see reference). Figure 1 Therefore, when the first gear 331 rotates, the fluid F is agitated by the teeth of the gear ring 321. The fluid F agitated by the gear ring 321 lubricates or cools the gears and bearings of the gear section 3. In addition, a portion of the agitated fluid F is stored in the tray section 464 (described later) and is also used for cooling the motor section 2 via the shaft 1.

[0063] <1-4. Shell 4>

[0064] The housing 4 houses the shaft 1, the motor portion 2, and the gear portion 3. The housing 4 has a first housing cylinder portion 41, a side plate portion 42, a housing cover portion 43, a cover member 44, a second housing cylinder portion 45, and a gear cover portion 46. Furthermore, the first housing cylinder portion 41, the side plate portion 42, the housing cover portion 43, the cover member 44, the second housing cylinder portion 45, and the gear cover portion 46 are formed, for example, using a conductive material; in this embodiment, they are formed using metallic materials such as iron, aluminum, or their alloys. Additionally, to suppress dissimilar metal contact corrosion at the contact portions, they are preferably formed using the same material. However, this is not a limitation; they may also be formed using materials other than metallic materials, and at least some of them may be formed using different materials.

[0065] The housing 4 houses the rotor 21 and the stator 22. The housing 4 has a third motor bearing housing 431 for holding the third motor bearing 4311. Furthermore, the third motor bearing housing 431 is an example of the "first bearing housing" of the present invention. As described above, the drive unit 100 includes the housing 4. Specifically, the housing 4 has a motor housing space 401. The motor housing space 401 is a space enclosed by the first housing cylindrical portion 41, the side plate portion 42, and the housing cover portion 43, which houses the rotor 21, the stator 22, the first motor bearing 4211, and the third motor bearing 4311, etc.

[0066] Furthermore, as described above, the housing 4 houses the gear section 3. In detail, the housing 4 has a gear section housing space 402. The gear section housing space 402 is a space enclosed by the side plate section 42, the second housing cylinder section 45, and the gear cover section 46, and houses the reduction gear 31 and the differential gear 32, etc.

[0067] A reservoir P for accumulating fluid F is disposed in the lower part of the gear housing space 402. A portion of the differential 32 is immersed in the reservoir P. The fluid F accumulated in the reservoir P is agitated by the operation of the differential 32 and supplied to the interior of the gear housing space 402. For example, when the gear ring 321 of the differential 32 rotates, the fluid F is agitated by the tooth surfaces of the gear ring 321. A portion of the agitated fluid F is supplied within the gear housing space 402 to each gear and bearing of the reduction gear 31 and the differential 32 for lubrication. In addition, another portion of the agitated fluid F is supplied to the interior of the shaft 1 and to the rotor 21 and stator 22 of the motor 2, as well as to each bearing within the gear housing space 402, for cooling and lubrication.

[0068] <1-4-1. First shell cylindrical section 41>

[0069] The first housing cylindrical portion 41 is cylindrical in shape, extending axially, and surrounds the rotation axis J1. The first housing cylindrical portion 41 is an example of the "housing cylindrical portion" of the present invention. As described above, the housing 4 has the first housing cylindrical portion 41. The motor portion 2, the fluid reservoir 54 (described later), etc., are disposed inside the first housing cylindrical portion 41. In addition, the stator core portion 221 is fixed to the inner surface of the first housing cylindrical portion 41.

[0070] <1-4-2. Side panel 42>

[0071] The side plate portion 42 covers the other axial end of the first housing cylinder portion 41 and one axial end of the second housing cylinder portion 45. The side plate portion 42 extends in a direction intersecting the rotation axis J1, dividing the first housing cylinder portion 41 and the second housing cylinder portion 45. In this embodiment, the first housing cylinder portion 41 and the side plate portion 42 are distinct parts of a single component. By integrally forming them, their rigidity can be improved. However, this is not limited to this example; they can also be different components.

[0072] The side plate portion 42 has a side plate through hole 4201 for inserting shaft 1 and a first drive shaft through hole 4202. The side plate through hole 4201 and the first drive shaft through hole 4202 extend axially through the side plate portion 42. The center of the side plate through hole 4201 coincides with the rotation axis J1. Shaft 1 is inserted into the side plate through hole 4201. The center of the first drive shaft through hole 4202 coincides with the drive axis J3. A drive shaft Ds1 on one axial side (D1) is inserted into the first drive shaft through hole 4202. An oil seal (not shown) is disposed in the gap between the drive shaft Ds1 and the first drive shaft through hole 4202 to seal the space between them.

[0073] Additionally, the side plate portion 42 also includes a first motor bearing housing 421, a second motor bearing housing 422, a first intermediate bearing housing 423, and a first output bearing housing 424. The first motor bearing housing 421 is disposed in the side plate portion 42 on one axial side (D1) of the side plate through hole 4201, holding the first motor bearing 4211. The second motor bearing housing 422 is disposed along the outer edge of the other axial end of the side plate through hole 4201, holding the second motor bearing 4221. The first intermediate bearing housing 423 is disposed on the other axial end face of the side plate portion 42, holding the first intermediate bearing 4231. The first output bearing housing 424 is disposed in the side plate portion 42 along the outer edge of the other axial end of the first drive shaft through hole 4202, holding the first output bearing 4241. In this embodiment, the first motor bearing 4211, the second motor bearing 4221, the first intermediate bearing 4231, and the first output bearing 4241 are ball bearings.

[0074] <1-4-3. Shell Cover 43>

[0075] The housing cover 43 extends in a direction intersecting the rotation axis J1, covering one axial end of the first housing cylinder 41. As described above, the housing 4 has a housing cover 43. The housing cover 43 is disposed and mounted on one axial end of the first housing cylinder 41. The housing cover 43 can be fixed to the first housing cylinder 41, for example, by using screws, but is not limited to this; methods such as screwing or pressing can be widely used to securely fix the housing cover 43 to the first housing cylinder 41. Thus, the housing cover 43 can fit tightly against one axial end of the first housing cylinder 41. Furthermore, tight fit refers to a degree of airtightness where the fluid F inside the component does not leak to the outside, and where external foreign matter such as water, dust, and dirt does not enter. The same applies to tight fit below.

[0076] The housing cover 43 also includes a third motor bearing housing 431. In other words, the drive unit 100 includes a third motor bearing housing 431. The third motor bearing housing 431 is disposed on the opposite axial end face of the housing cover 43. The third motor bearing housing 431 holds the third motor bearing 4311. The drive unit 100 includes the third motor bearing 4311. The third motor bearing 4311 rotatably supports the shaft 1 and is lubricated by fluid F. The third motor bearing 4311 is an example of the "first bearing" of the present invention, which in this embodiment is a ball bearing.

[0077] The third motor bearing housing 431 has an opening 4312 through which the shaft 1 passes. In other words, the housing cover 43 has an opening 4312 through which the shaft 1 is inserted. The opening 4312 extends axially through the housing cover 43 and surrounds the rotation axis J1 when viewed from the axial direction.

[0078] Additionally, the housing cover 43 also has a detector holder 432 for holding the rotating detector 7. In this embodiment, the detector holder 432 is a step disposed on one axial side D1 of the housing cover 43. This step is annular, surrounding the rotation axis J1.

[0079] <1-4-4. Cover Component 44>

[0080] The cover member 44 is disposed on one axial end face of the housing cover portion 43, covering the opening 4321. As described above, the housing 4 has the cover member 44. The cover member 44 can be installed on the housing cover portion 43 by means of threaded fastening, but is not limited to this; methods such as screwing or pressing can be widely used to securely fix the cover member 44 to the housing cover portion 43. In this embodiment, the cover member 44 and the housing cover portion 43 together form a space 403. The space 403 is the space enclosed by the housing cover portion 43 and the cover member 44, accommodating one axial end face of the shaft 1, the rotation detector 7, the second sealing member 82, etc.

[0081] The cover component 44 has a plate portion 441 and a first columnar portion 442. The plate portion 441 is a plate-shaped portion that extends in a direction intersecting the rotation axis J1, and in this embodiment, it extends radially from the rotation axis J1. The plate portion 441 is positioned at a position D1 closer to one axial end of the shaft 1, covering the opening 4312 and one axial end of the shaft 1. The first columnar portion 442 extends axially along the rotation axis J1. The housing 4 has the first columnar portion 442. Specifically, the first columnar portion 442 extends from the plate portion 441 in the other axial direction D2. When viewed axially, the center of the first columnar portion 442 coincides with the rotation axis J1. The other axial direction D2 side of the first columnar portion 442 is housed in the hollow portion 12 at one axial end of the shaft cylinder portion 11.

[0082] <1-4-5. Second shell cylindrical section 45>

[0083] The second housing cylindrical portion 45 is cylindrical, surrounding the rotation axis J1, and extends axially. One axial end of the second housing cylindrical portion 45 is connected to and covered by the side plate portion 42. In this embodiment, the second housing cylindrical portion 45 is detachably mounted to the other axial end of the side plate portion 42. Furthermore, the mounting of the second housing cylindrical portion 45 to the side plate portion 42 can be exemplified by fixing with screws, but is not limited to this; methods such as screwing or pressing can be widely used to securely fix the second housing cylindrical portion 45 to the side plate portion 42. Thus, the second housing cylindrical portion 45 can be tightly fitted to the other axial end of the side plate portion 42.

[0084] <1-4-6. Gear cover 46>

[0085] The gear cover portion 46 extends in a direction intersecting the rotation axis J1. A gear portion 3 is disposed inside the second housing cylinder portion 45 and the gear cover portion 46. In this embodiment, the second housing cylinder portion 45 and the gear cover portion 46 are different parts of a single component. However, this is not a limitation to this example; the second housing cylinder portion 45 and the gear cover portion 46 may also be different components.

[0086] The gear cover portion 46 has a second drive shaft through hole 460. The center of the second drive shaft through hole 460 is aligned with the drive axis J3. A drive shaft Ds is inserted into the second drive shaft through hole 460. An oil seal (not shown) is disposed in the gap between the drive shaft Ds on the other axial side D2 and the second drive shaft through hole 460.

[0087] The gear cover 46 also includes a fourth motor bearing housing 461, a second intermediate bearing housing 462, and a second output bearing housing 463. These bearing housings 461, 462, and 463 are disposed in the gear portion receiving space 402 on one axial end face of the gear cover portion 46. The fourth motor bearing housing 461 and the second intermediate bearing housing 462 are disposed on one axial end face of the gear cover portion 46. The fourth motor bearing housing 461 holds the fourth motor bearing 4611. The second intermediate bearing housing 462 holds the second intermediate bearing 4621. The second output bearing housing 463 is disposed in the gear cover portion 46 along the outer edge of one axial end of the second drive shaft through hole 460, holding the second output bearing 4631. In this embodiment, the fourth motor bearing 4611, the second intermediate bearing 4621, and the second output bearing 4631 are ball bearings.

[0088] Additionally, the gear cover portion 46 has a tray portion 464 and a flow path 465. The tray portion 464 is disposed on one axial end face of the gear cover portion 46 and has a recessed portion that is recessed vertically downward. The tray portion 464 can store the fluid F stirred up by the gear ring 321. The flow path 465 is the passage for the fluid F, connecting the tray portion 464 and the inlet 111 of the shaft 1. The fluid F accumulated in the tray portion 464 is supplied to the flow path 465 and flows into the hollow portion 12 from the inlet 111 at the other axial end of the shaft 1.

[0089] <1-5. Liquid Circulation Section 5>

[0090] Next, the liquid circulation unit 5 will be described. The liquid circulation unit 5 includes a piping unit 51, a pump 52, a cooler unit 53, and a fluid storage tank 54.

[0091] The piping section 51 connects the pump 52 to the fluid reservoir 54 disposed inside the first housing cylindrical section 41, supplying fluid F to the fluid reservoir 54. The pump 52 draws in fluid F accumulated in the lower region of the gear receiving space 402. The pump 52 is an electric pump, but is not limited to it. For example, it may be a structure driven by a portion of the power of the shaft 1 of the drive unit 100.

[0092] The cooler unit 53 is disposed in the piping section 51 between the pump 52 and the fluid reservoir 54. That is, the fluid F drawn by the pump 52 is transported to the fluid reservoir 54 after passing through the cooler unit 53 via the piping section 51. A refrigerant, such as water supplied from an external source, is supplied to the cooling unit 53. The cooler unit 53 performs heat exchange between the refrigerant and the fluid F, thereby reducing the temperature of the fluid F.

[0093] The fluid reservoir 54 is a tray disposed inside the motor housing space 401, vertically above the stator 22. A drip hole (notation omitted) is formed at the bottom of the fluid reservoir 54, through which fluid F is dripped to cool the motor section 2. The drip hole is formed, for example, above the coil end 2221 of the coil section 222 of the stator 22, which is cooled by the fluid F.

[0094] <1-6. Conductor Bearing 6>

[0095] Next, the conductive bearing 6 will be described. The conductive bearing 6 is disposed between the shaft 1 and the housing 4 to rotatably support the shaft 1. As described above, the drive device 100 includes the conductive bearing 6. The conductive bearing 6 is an example of the "second bearing" of the present invention in this embodiment, which is a ball bearing in this embodiment.

[0096] The conductive bearing 6 is lubricated by a lubricating material 61 with a conductivity higher than that of the fluid F. In this embodiment, the lubricating material 61 is a conductive grease. Conductive materials such as copper powder and carbon powder are added to the grease or other lubricating oil. The conductive bearing 6 can electrically connect the shaft sleeve portion 11 to the first columnar portion 442 through the lubricating material 61. For example, the inner and outer rings of the ball bearing are electrically connected through the lubricating material 61, therefore, the shaft sleeve portion 11 is electrically connected to the first columnar portion 442 of the housing 4.

[0097] The conductive bearing 6 is disposed in a space isolated from the third motor bearing housing 431. In this embodiment, this space is the shaft recess 14. By lubricating the third motor bearing 4311 with an electrically insulating fluid F, such as ATF (automatic transmission fluid), the lubricity of the third motor bearing 4311 can be ensured, and electrical insulation between the shaft 1 and the housing 4 can be achieved within the third motor bearing 4311. For example, if the third motor bearing 4311 is a ball bearing, insulation can be achieved between the outer ring fixed to one of the shaft 1 and the housing 4 and the inner ring fixed to the other of the shaft 1 and the housing 4. In addition, the conductive bearing 6 is disposed between the shaft 1 and the housing 4 and is lubricated by a conductive lubricating material 61. Since the conductive bearing 6 is disposed in a space isolated from the third motor bearing housing 431 (shaft recess 14 in this embodiment), the fluid F that lubricates and cools the stator 22 and the third motor bearing 4311 is unlikely to act on the conductive bearing 6. Therefore, fluid F can be prevented from mixing into the lubricating material 61, thus preventing a decrease in the electrical conductivity of the lubricating material 61. Therefore, the conductive bearing 6 can maintain a good electrical connection with the shaft 1 and the first columnar portion 442 of the housing 4. Thus, through the conductive bearing 6, the current generated by the potential fluctuations within the shaft 1 can be sufficiently discharged to the housing 4.

[0098] The through bearing 6 and the third motor bearing 4311 are arranged coaxially. For example, they are arranged in a ring around the same axis (i.e., the rotation axis J1). In this way, the through bearing 6, together with the third motor bearing 4311, can more stably support the shaft 1 for rotation.

[0099] In this embodiment, the through bearing 6 is embedded in the shaft recess 14. For example, the radially outer end of the through bearing 6 (e.g., the outer ring of a ball bearing) engages with the inner circumferential surface of the shaft recess 14. The radially inner end of the through bearing 6 (e.g., the inner ring of a ball bearing) engages with the radially outer side of the first columnar portion 442. Thus, since the through bearing 6 is embedded and held in the shaft recess 14, there is no need to ensure space outside the shaft 1 for arranging the through bearing 6 and for holding the bearing housing. Therefore, the drive device 100 can be miniaturized. However, it is not limited to this example; the through bearing 6 can also be fixed to the shaft recess 14 by methods other than the above-described engagement structure (welding, brazing, etc.).

[0100] The conductor bearing 6 is disposed inside the shaft sleeve portion 11 at a position D1 axially further than the shaft wall portion 13. The second shaft through hole 102 is disposed at a position D2 axially further than the shaft wall portion 13. In this way, the space within the shaft sleeve portion 11 for the flow of fluid F can be isolated from the space for the conductor bearing 6 by means of the shaft wall portion 13. For example, the hollow portion 12 within the shaft sleeve portion 11 can be divided into a space on the side D2 axially further than the shaft wall portion 13 of the hollow portion 12 and a shaft recess 14. The former is for the flow of fluid F, and the latter is for the placement of the conductor bearing 6. Therefore, fluid F can be prevented from being directly applied to the conductor bearing 6.

[0101] <1-7. Rotation Detector 7>

[0102] The rotation detector 7 is installed on the axial side D1 of the housing cover 43. The rotation detector 7 is positioned axially closer to the third motor bearing housing 431 by a distance D1, and detects the rotation angle of the shaft 1. In this embodiment, the rotation detector 7 is a resolver having a resolver rotor and a resolver stator. The rotation detector 7 has a resolver rotor (not shown) fixed to the shaft 1 and a resolver stator (not shown) fixed to the housing cover 43 of the housing 4. The resolver rotor and resolver stator are annular. The inner circumferential surface of the resolver stator is radially opposed to the outer circumferential surface of the resolver rotor. The resolver stator periodically detects the rotation angle position of the resolver rotor as the rotor 21 rotates. Thus, the rotation detector 7 obtains information about the rotation angle position of the rotor 21. However, not limited to the example of this embodiment, the rotation detector 7 may not be a resolver; for example, it may be a rotary encoder.

[0103] <1-8. First sealing component 81>

[0104] The first sealing member 81 is disposed within the shaft sleeve portion 11 at a position D1 axially closer than the conduction bearing 6. In this embodiment, the shaft 1 has the first sealing member 81. The first sealing member 81 is annular in shape surrounding the rotation axis J1. In this embodiment, the first sealing member 81 is fixed to the radially outer side of the first columnar portion 442 and extends radially outward (see reference). Figure 2 However, not limited to this example, the first sealing member 81 may also be fixed to the inner circumferential surface of the shaft sleeve portion 11 and extend radially inward. That is, the first sealing member 81 may be fixed to one of the inner circumferential surface of the shaft sleeve portion 11 and the radially outer surface of the first columnar portion 442, and may extend radially from one of them toward the other.

[0105] Thus, at a position within the shaft sleeve 11 on the axial side D1 relative to the through bearing 6, the gap between the inner circumferential surface of the shaft sleeve 11 and the radially outer surface of the first columnar portion 442 can be covered by the radially extending first sealing member 81. Here, at one axial end of the shaft 1, fluid F used for lubricating and cooling various parts of the drive device 100, such as mist, may sometimes intrude into the shaft sleeve 11. Even if such intrusion of fluid F occurs, the intrusion of fluid F from the axial side D1 to the axial side D2 of the first sealing member 81 can be suppressed or prevented. Therefore, the action of fluid F on the through bearing 6 can be effectively suppressed or prevented.

[0106] In this embodiment, the first sealing member 81 is an oil slinger ring having a fixed portion (reference numerals omitted) and a flange portion (reference numerals omitted). The fixed portion of the oil slinger ring is cylindrical, extending axially. The flange portion is plate-shaped, extending radially from the fixed portion, and covers the gap between the radially extending cylindrical portion 11 and the first columnar portion 442. However, the first sealing member 81 is not limited to this example. The first sealing member 81 may also be an oil seal, a mechanical seal, a gasket, etc.

[0107] <1-9. Second sealing component 82>

[0108] The second sealing member 82 is disposed radially outward from the shaft 1. As described above, the drive device 100 also includes the second sealing member 82. The second sealing member 82 is disposed between the third motor bearing 4311 in the axial direction and one axial end of the shaft 1. Specifically, the second sealing member 82 is annular, surrounding the rotation axis J1, and covers the gap between the shaft 1 and the housing cover 43 (in other words, the inner circumferential surface of the opening 4312). In this way, by dividing the third motor bearing housing 431 with the second sealing member 82, the fluid F lubricating the third motor bearing 4311 can be suppressed or prevented from being applied to the conductive bearing 6. Therefore, the reduction of conductivity of the conductive bearing 6 can be suppressed.

[0109] Preferably, the second sealing member 82 is disposed between the third motor bearing 4311 and the rotary detector 7 in the axial direction. The second sealing member 82 divides the third motor bearing housing 431 and the space 403 for the rotary detector 7 to be disposed. In this way, the fluid F that lubricates the third motor bearing 4311 can be suppressed or prevented from being applied to the rotary detector 7 by the second sealing member 82. In addition, this example does not exclude a structure in which the second sealing member 82 is disposed at a position D1 further axially than the rotary detector 7.

[0110] In this embodiment, the second sealing member 82 is disposed on the exterior of one axial end of the opening 4312. However, the configuration of the second sealing member 82 is not limited to the example of this embodiment. For example, the second sealing member 82 may be disposed inside the opening 4312. Furthermore, it is preferable that the second sealing member 82 is disposed at a position D1 axially closer than the radially outer end of the second axial through hole 102. This can suppress or prevent the fluid F flowing out of the second axial through hole 102 from being applied to the rotation detector 7. However, this example does not preclude a structure in which the second sealing member 82 is disposed at a position D2 axially closer than the radially outer end of the second axial through hole 102.

[0111] In this embodiment, the second sealing member 82 is an oil slinger ring having a fixed portion (omitted) and a flange portion (omitted). The fixed portion of the oil slinger ring is cylindrical, extending axially. The flange portion is plate-shaped, extending radially from the fixed portion, covering the gap between the radially extending cylindrical portion 11 and the housing cover portion 43 (the inner circumferential surface of the opening 4312). However, the second sealing member 82 is not limited to this example. The second sealing member 82 may also be an oil seal, a mechanical seal, a gasket, etc. Alternatively, the second sealing member 82 may be part of the third motor bearing 4311. That is, the third motor bearing 4311 may also be a sealed ball bearing including the second sealing member 82. Or, the second sealing member 82 may also be part of the conductive bearing 6. That is, the conductive bearing 6 may also be a sealed ball bearing including the second sealing member 82 and the lubricating material 61.

[0112] <2. First Variation>

[0113] Next, refer to Figure 4 and Figure 5 The first variation of the implementation method will be described. Figure 4 This is a conceptual diagram illustrating an example of the shaft-discharge structure of the first modified example. Figure 5 This is a conceptual diagram illustrating another example of the shaft-discharge structure involved in the first modified example. Additionally, Figure 4 and Figure 5 This is just a conceptual diagram; the configuration and dimensions of each component are not strictly identical to the actual drive unit 100. Furthermore, Figure 4 and Figure 5Corresponding to Figure 1 The portion A enclosed by the dashed line. Hereinafter, a structure different from the above embodiment will be described. Furthermore, components identical to those in the above embodiment will be labeled with the same symbols, and their descriptions will be omitted.

[0114] In the first modified example, the drive device 100 replaces the first columnar portion 442 and the conductive bearing 6 (see reference). Figure 2 The shaft 1 includes a second columnar portion 15, a conductive bearing housing 443, and a conductive bearing 4431. Specifically, the shaft 1 has a second columnar portion 15. The second columnar portion 15 extends axially to one side (D1) from the shaft wall portion 13 toward the rotation axis J1. When viewed axially, the center of the second columnar portion 15 coincides with the rotation axis J1. The axial side (D1) of the second columnar portion 15 is housed in the conductive bearing housing 443. Additionally, the cover member 44 has a plate portion 441. The cover member 44 also has a conductive bearing housing 443 that holds the conductive bearing 4431. The conductive bearing 4431 rotatably supports the second columnar portion 15. The conductive bearing 4431 is an example of the "second bearing" of the present invention in the first variation, and it is a ball bearing having the same structure as the conductive bearing of the embodiment. For example, the conductive bearing 4431 is lubricated by a lubricating material 4432 of a specific fluid F. The conductive bearing housing 443 is disposed on the other axial end face of the plate portion 441. When viewed from the axial direction, the center of the conductive bearing housing 443 coincides with the rotation axis J1.

[0115] According to the first modification, the space where the fluid F flows within the shaft sleeve portion 11 can be isolated from the space 403 where the conductive bearing 4431 is disposed via the shaft wall portion 13. Furthermore, the former space... Figure 4 The middle part is hollow section 12, in Figure 5 The hollow portion 12 is located on the axial side D2 of the shaft wall portion 13. For example, by using the shaft wall portion 13 to block one axial end of the shaft cylinder portion 11, fluid F can be prevented from flowing out of one axial end of the shaft cylinder portion 11 to the outside of the shaft 1. Therefore, fluid F can be prevented from being applied to the conductive bearing 4431.

[0116] Furthermore, since the conductive bearing 4431 that rotatably supports the second columnar portion 15 is held by the conductive bearing seat 443 of the cover member 44, the current generated by the potential change generated in the shaft 1 can be discharged to the cover member 44 of the housing 4 via the second columnar portion 15, the conductive bearing 4431 and the conductive bearing seat 443.

[0117] In addition, Figure 4 In this configuration, the shaft wall portion 13 is disposed at one axial end of the shaft sleeve portion 11. Therefore, the shaft 1 does not have a shaft recess portion 14 (see reference). Figure 2 However, it is not limited to Figure 4 For example, shaft 1 can also have a shaft recess 14. For example, as... Figure 5As shown, the shaft wall portion 13 can also be positioned on one axial side (D1) of the shaft cylinder portion 11 at a position closer to the other axial side (D2) than one axial end of the shaft cylinder portion 11. Furthermore, at least the other axial side (D2) of the conduction bearing housing 443 can also be housed inside the shaft cylinder portion 11. Figure 5 The shaft is housed in the recess 14. This eliminates the need to ensure space outside the shaft 1 (particularly on the axial side D1 of the shaft sleeve 11) for accommodating the guide bearing 4431 and the guide bearing housing 443. Therefore, the increase in the axial dimension of the drive unit 100 can be suppressed, thus contributing to the miniaturization of the drive unit 100.

[0118] <3. Second variation>

[0119] Next, refer to Figure 6 A second variation of the implementation method will be described. Figure 6 This is a conceptual diagram illustrating an example of the shaft-discharge structure in the second modified version. Additionally, Figure 6 This is just a conceptual diagram; the configuration and dimensions of each part are not necessarily identical to the actual drive unit 100. Furthermore, Figure 6 Corresponding to Figure 1 The portion A enclosed by the dashed line. Hereinafter, structures different from the above-described embodiment and the first variation will be described. Furthermore, components identical to those in the above-described embodiment and the first variation are sometimes labeled with the same reference numerals, and their descriptions are omitted.

[0120] In the second variation, based on the first variation, the drive device 100 includes a conductive bearing 4331 and a conductive bearing seat 433 to replace the first columnar portion 442 and the conductive bearing 6 (see reference) of the embodiment. Figure 2 ), the second columnar portion 15 of the first modified example, the conductive bearing housing 443 and the conductive bearing 4431 (see reference) Figure 4 and Figure 5 ), etc. Specifically, the conductive bearing 4331 is disposed together with the third motor bearing 4311 on the radially outer side of the shaft 1. In the second variation, the conductive bearing 4331 is an example of the "second bearing" of the present invention, and is a ball bearing having the same structure as the conductive bearing 6 of the embodiment. For example, the conductive bearing 4331 is lubricated by a lubricating material 4332 with a conductivity higher than that of the fluid F. The conductive bearing 4331 is disposed at a position D1 axially closer than the third motor bearing 4311. Furthermore, the conductive bearing housing 433 holds the conductive bearing 4331. The housing 4 also has a conductive bearing housing 433. In the second variation, the conductive bearing housing 433 is an example of the "second bearing housing" of the present invention. When viewed axially, the center of the conductive bearing housing 443 coincides with the rotation axis J1.

[0121] exist Figure 6In this configuration, the through bearing 4331 is disposed on one axial side (D1) of the opening 4312. The radially inner end (e.g., the inner ring) of the through bearing 4331 is fixed to the outer circumferential surface of the shaft sleeve portion 11. The radially outer end (e.g., the outer ring) of the through bearing 4331 is fixed to the inner circumferential surface of the opening 4312 of the housing cover portion 43. That is, in Figure 6 In this context, the conductor bearing housing 433 is the outer edge of one end of the opening 4312 of the housing cover portion 43 along the axial direction. However, it is not limited to... Figure 6 For example, a through bearing seat 433 may also be provided on one end face of the housing cover 43 in the axial direction outside the opening 4312.

[0122] In the second variation, it is preferred to be as follows: Figure 6 As shown, the second sealing member 82 is axially disposed between the third motor bearing 4311 and the conductive bearing 4331, dividing the third motor bearing housing 431 and the conductive bearing housing 433. In this way, by dividing the third motor bearing housing 431 and the conductive bearing housing 433 with the second sealing member 82, the fluid F lubricating the third motor bearing housing 431 can be suppressed or prevented from being applied to the conductive bearing housing 433. Therefore, the decrease in conductivity of the conductive bearing housing 433 can be suppressed. Furthermore, since the third motor bearing housing 431 and the conductive bearing housing 433 are located on the radially outer side of the shaft 1, the conductive bearing housing 433 can be positioned near the third motor bearing 4311. Therefore, electrical conduction in the third motor bearing housing 431 lubricated by the electrically insulating fluid F can be more effectively suppressed or prevented. For example, discharge between the inner and outer rings of a ball bearing can be effectively suppressed or prevented.

[0123] <4. Other>

[0124] The embodiments of the present invention have been described above. However, the scope of the present invention is not limited to the embodiments described above. The present invention can be implemented by making various modifications to the above embodiments without departing from the spirit of the invention. Furthermore, the items described in the above embodiments can be appropriately combined arbitrarily without causing contradictions.

[0125] Industrial applications

[0126] This invention can be used in devices that enable the grounding of rotating shafts. Furthermore, this invention is useful for motors mounted on vehicles, but it is also useful for motors used for purposes other than vehicle operation.

Claims

1. A driving device, comprising: A shaft that extends axially along the axis of rotation; A rotor, fixed to the shaft, capable of rotating about the axis of rotation; A stator, which is radially spaced apart from the rotor; A first bearing, which rotatably supports the shaft and is lubricated by a fluid; A housing having a first bearing seat for holding the first bearing and for housing the rotor and the stator; as well as A second bearing, disposed between the shaft and the housing, rotatably supports the shaft and is lubricated by a lubricating material with a higher conductivity than the fluid. The second bearing is disposed in a space isolated from the first bearing housing. The shaft has: The shaft sleeve portion surrounds the axis of rotation; and A through-hole, which penetrates the shaft cylinder in a radial direction or in a direction intersecting the radial and axial directions. The fluid can flow inside the shaft sleeve and be supplied to the first bearing through the shaft through hole. The shaft also has a shaft wall portion, which is disposed inside the shaft cylinder portion and extends radially. The radially outer end of the shaft wall portion is connected to the inner circumferential surface of the shaft cylinder portion. The second bearing is disposed inside the shaft sleeve at a position axially closer than the shaft wall portion. The shaft through hole is located on the opposite side of the shaft wall.

2. The driving device according to claim 1, wherein, The second bearing is arranged coaxially with the first bearing.

3. The driving device according to claim 1 or 2, wherein, The housing has a first columnar portion extending axially along the axis of rotation. The shaft has a recessed portion that extends from one axial end of the shaft to the other axial end. The shaft recess receives at least one axial side of the first columnar portion. The second bearing is fitted into the shaft recess. The radial inner end of the second bearing is connected to the radial outer side of the first columnar portion.

4. The driving device according to claim 3, wherein, The shaft also has a first sealing member disposed within the shaft sleeve at a position axially closer than the second bearing. The first sealing member is fixed to one of the inner circumferential surface of the shaft cylinder and the radial outer surface of the first columnar portion, and extends radially from one side toward the other.

5. The driving device according to claim 1 or 2, wherein, The housing includes: A housing cylindrical portion that extends axially and surrounds the axis of rotation; A housing cover having an opening for insertion of the shaft and disposed at one axial end of the housing cylinder; and A cover component, disposed at one axial end of the housing cover portion, covers the opening. The shaft has: The shaft sleeve portion is rotatably supported by the first bearing in a manner that surrounds the axis of rotation; The shaft wall portion is disposed on one axial side of the shaft cylinder portion and extends radially; and The second columnar portion extends axially from the axial wall portion. The cover component has a second bearing housing that holds the second bearing. The second bearing can rotatably support the second columnar portion.

6. The driving device according to claim 5, wherein, At least one axial side of the second bearing housing is housed inside the shaft sleeve portion.

7. The driving device according to claim 1 or 2, wherein, It also includes a second sealing component, which is disposed radially outward of the shaft and axially disposed between the first bearing and one of the axial ends of the shaft.

8. The driving device according to claim 1 or 2, wherein, It also includes a second sealing component, which is positioned radially outward from the shaft. The second bearing, together with the first bearing, is disposed on the radially outer side of the shaft. The housing also has a second bearing housing for holding the second bearing. The second sealing component is disposed between the first bearing and the second bearing in the axial direction, dividing the first bearing housing and the second bearing housing.

9. A type of vehicle, The drive device having any one of claims 1 to 8.

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