Vehicular power unit

Abstract

To provide a vehicular power unit which can prevent degradation in seal life while obtaining a desired motor output.SOLUTION: A wheel bearing 30 of a vehicular power unit PU has: a fixed ring 2; and a rotary ring 1 which is supported via a rolling element 5 in a manner rotatable with respect to the fixed ring 2. A power generator GE of the vehicular power unit PU has: a stator 9 fitted to the fixed ring 2; and a rotor 12 fitted to the rotary ring 1. The stator 9 is fitted to an inboard-side outer peripheral surface of an inner ring shaft 3, which is the fixed ring, via a stator holding member 17. A communication hole 25 which leads wiring 20 of a coil of the stator 9 to the outside is provided at a location radially inner side than the stator 9 on an end surface on the inboard side of the stator holding member 17. A seal member 16 which prevents a foreign object from entering an inner space is provided on an outer diameter surface at an end on the inboard side of the stator holding member 17.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a vehicle power plant that has a motor generator that performs driving and regenerative braking mounted on driving wheels that are mechanically connected to a main drive source of the vehicle or on non-driven wheels (driven wheels) that are not connected to the main drive source. [Background technology]

[0002] A vehicle power unit with a motor built into the wheel is a unit that integrates a wheel bearing that supports the wheel with a motor that drives the wheel and regenerates electricity. Such a vehicle power unit has many advantages, such as assisting the vehicle's drive, regenerating electricity during deceleration, and stabilizing posture by controlling the torque of each wheel, and is expected to become increasingly popular in the future as automobiles become more electrified (for example, Patent Documents 1 to 4). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-052482 A [Patent Document 2] JP 2019-202570 A [Patent Document 3] Patent No. 7025176 [Patent Document 4] Patent Publication No. 2021-192998 Summary of the Invention [Problem to be solved by the invention]

[0004] The vehicle power unit of Patent Document 1 is small and can be positioned on the inner diameter side of the outer periphery of the brake rotor, making it easy to replace the current wheel bearing. However, with the structure of Patent Document 1, if an abnormality or deterioration occurs in the wheel bearing, the entire vehicle power unit including the motor must be replaced. This makes the replacement work difficult and the cost of the replacement parts high. Therefore, the device of Patent Document 2 makes it possible to separate the wheel bearing unit and the motor unit. This makes it easier to replace the wheel bearing unit when replacing one of the parts, and reduces the replacement cost.

[0005] In the structure of Patent Document 2, there is a fastening portion between the outer ring and the outer ring peripheral body on the outer diameter part of the rolling surface, and fixing with a bolt is appropriate to ensure ease of replacement. However, since the bolt strength is required to withstand the load from the road surface, the fastening portion between the outer ring and the outer ring peripheral body becomes thick on the outer diameter side. As a result, the space occupied by the motor portion located on the outer diameter side becomes smaller, and as a result, it is difficult to obtain the desired motor output.

[0006] In the device of Patent Document 3, in order to increase the space occupied by the motor unit, a plurality of communication holes are provided in the stator holding member that holds the stator of the motor, and the wiring connected to the stator is passed through the communication holes from the outer diameter side to the inner diameter side of the stator holding member. However, since the stator holding member is attached to the outer ring, which is a fixed ring, the radial mounting position (PCD) of the bolt that fixes the wheel bearing to the knuckle is arranged radially outward from the PCD of the rolling element of the wheel bearing. For this reason, the seal member arranged radially outward from the PCD of the bolt becomes larger in diameter. As a result, the seal peripheral speed during wheel rotation increases, and there is a risk of the seal life being reduced.

[0007] In the device of Patent Document 4, the wheel bearing is an outer ring rotating type, and a bracket is fastened to the shaft part protruding from the inner ring to the inboard side with a nut, and the bracket and the knuckle are fastened to each other with a bolt. This makes it possible to separate the wheel bearing, the motor rotor, and the motor stator without disassembling the wheel bearing, and also ensures the radial occupation space of the motor. However, Patent Document 4 does not provide a detailed description of the wiring for supplying power to the motor stator. In addition, the PCD of the bolt is arranged radially outward from the PCD of the rolling element of the wheel bearing, and the seal member arranged radially outward from the PCD of the bolt has a large diameter. As a result, the seal peripheral speed during wheel rotation increases, and there is a risk that the seal life will be reduced.

[0008] The object of the present invention is to provide a power unit for a vehicle that can secure the space occupied by the motor section to obtain the desired motor output, while reducing the diameter of the seal to prevent a decrease in seal life due to an increase in the seal peripheral speed during wheel rotation. [Means for solving the problem]

[0009] The vehicle power unit of the present invention comprises: a wheel bearing including a fixed ring and a rotating ring rotatably supported by the fixed ring via rolling elements, the rotating ring being provided with a hub flange to which a wheel of a vehicle is attached; A vehicle power unit including a generator having a stator attached to a fixed ring of the wheel bearing and a rotor attached to a rotating ring of the wheel bearing, The stator is attached to an inboard outer peripheral surface of an inner ring shaft of the wheel bearing which is the fixed ring via a stator holding member, a communication hole for leading out wiring of the coil of the stator to the outside is provided at a portion radially inward from the stator in an inboard end face of the stator holding member, A seal member for preventing intrusion of foreign matter into the internal space is provided on the outer diameter surface of the inboard end of the stator holding member.

[0010] Here, "radial direction" refers to the radial direction of the wheel bearing. Furthermore, when the vehicle power unit is mounted on the vehicle body, the direction toward the vehicle body centerline extending in the front-rear direction of the vehicle is referred to as the "inboard side," and the direction away from the vehicle body centerline is referred to as the "outboard side."

[0011] With this configuration, the wiring coming out of the coil on the inboard side of the generator is led out from a communication hole radially inward of the stator. In other words, the wiring extends radially inward from the stator and then led out to the inboard side. This ensures space on the inboard side of the stator, and this space can be effectively used for the motor winding coil. As a result, the desired motor output can be obtained.

[0012] In addition, the wheel bearing is an outer ring rotating type, and the inner ring shaft, which is a fixed ring, is connected to the vehicle body by a fastening member. In other words, the fastening member is located radially inward and close to the axis of the wheel bearing. This allows the diameter of the seal member to be made small. Furthermore, the communication hole that leads the generator wiring to the outside is located radially inward from the stator. In other words, the communication hole is arranged on the inner diameter side that is close to the axis of the wheel bearing. This allows the diameter of the seal member that is installed radially outward from the communication hole to be made small. This makes it possible to suppress an increase in the seal peripheral speed when the wheel rotates, and to suppress deterioration of the seal member due to heat generation during high-speed rotation, etc.

[0013] In the present invention, the inner ring shaft may be attached to the vehicle suspension by a bolt, and the radial position of the axis of the bolt may be the same as the radial position of the center of the rolling element or may be located on the inner diameter side. With this configuration, the bolt is located radially inside and close to the axis of the wheel bearing. Therefore, the diameter of the seal member can be made small, so that an increase in the seal peripheral speed during wheel rotation can be suppressed, and deterioration of the seal member due to heat generation during high-speed rotation can be suppressed.

[0014] In the present invention, the present invention may further include a rotation detector that detects a rotation angle or rotation speed of the rotating wheel relative to the fixed wheel, a brake rotor is attached to the hub flange, a part or all of the stator and the rotor have a smaller diameter than a portion of the brake rotor against which a brake caliper is pressed, the entire generator except for the portion where it is attached to the hub flange is located in the axial range between the hub flange and an outboard side surface of an undercarriage frame component of the vehicle, and the rotation detector is located radially inward of the rotor. With this configuration, the vehicle power unit including the rotation detector and the stator and rotor of the generator can be arranged compactly.

[0015] In the present invention, a plurality of female threads may be provided on a flange portion at an inboard end portion of the inner shaft, and the inner shaft may be attached to a suspension device of a vehicle by fastening bolts to the female threads. Also, a female thread may be provided on an inboard end surface of the inner shaft, and the inner shaft may be attached to a suspension device of a vehicle by fastening a bolt to the female thread. Alternatively, the inner shaft may be provided with a male thread protruding from an inboard end face, and the inner shaft may be attached to a suspension device of a vehicle by tightening a nut onto the male thread.

[0016] In either mounting structure, the bolts or nuts are located radially inward and close to the axis of the wheel bearing, so that the diameter of the seal member can be made small, which prevents the seal member from deteriorating due to heat generation during high-speed rotation.

[0017] In the present invention, when a rotation detector is provided for detecting at least one of the rotation angle and rotation speed of the rotating wheel relative to the fixed wheel, a target for the rotation detector may be provided on an outer wheel cap that closes the outboard end of the outer wheel, which is the rotating wheel, a sensing part of the rotation detector may be provided on the outboard end face of the inner wheel shaft, and a through hole may be provided in the inner wheel shaft for extracting a signal line of the rotation detector.

[0018] Furthermore, when the rotation detector is provided, a target of the rotation detector may be provided on the outer periphery of the outer ring, which is the rotating ring, and a sensing portion of the rotation detector may be provided on the outboard end face of the stator holding member. Alternatively, the target of the rotation detector may be provided on a seal holder that is attached to the outer ring, which is the rotating ring, and closes the inboard end of the vehicle power unit, and the sensing portion of the rotation detector may be provided on the stator holding member. Alternatively, the target of the rotation detector may be provided on the outer periphery of the inboard portion of the outer ring, which is the rotating ring, and the sensing portion of the rotation detector may be provided on the inner periphery of the inboard portion of the stator holding member.

[0019] With any of the above-mentioned arrangements of the target and sensing portion, the rotation detector can be arranged compactly on the wheel bearing.

[0020] In the present invention, the wheel bearing may have an outboard side inner ring arranged on an outer periphery on the outboard side of the inner shaft, the inner shaft being fitted into the outboard inner ring from the inboard side, and the outboard side shaft end of the inner shaft being crimped radially outward. In this case, the wheel bearing may further have an inboard side inner ring arranged on the inboard side of the inner shaft, the inner shaft being fitted into the outboard and inboard side inner rings from the inboard side, and the outboard side shaft end of the inner shaft being crimped radially outward.

[0021] Conventionally, in wheel bearings of the outer ring rotating type used for automobile wheels, a shaft is inserted into the inner ring, and a preload is applied to the bearing by tightening with a fastening member such as a nut. In this configuration, the axial fastening force to the inner ring is controlled by controlling the fastening torque of the fastening member, but the fastening torque and the axial fastening force are influenced by the contact state of the threaded portion, particularly the static friction coefficient of the contact portion. In other words, even if the fastening torque is controlled, if the contact state (static friction coefficient) of the threaded portion is not controlled, the relationship between the fastening torque and the fastening force will not satisfy the design concept, and the desired fastening force will not be applied, which may make it impossible to control the preload.

[0022] Even if the desired fastening force is applied during assembly, it may be difficult to maintain the desired fastening force if the condition of the contact area changes. If the desired fastening force is not applied, the nut may loosen due to vibrations during driving, causing the wheel to become unstable.

[0023] According to the above configuration, the inner ring shaft is fitted into the outboard and inboard inner rings from the inboard side, and the outboard side shaft end of the inner ring shaft is crimped radially outward to apply a preload. This allows the preload on the wheel bearing to be appropriately controlled in a wheel bearing with a power generation function. By appropriately controlling the preload, a desired fastening force is maintained, and loosening of the nut due to vibration during driving can be prevented. Furthermore, since the preload control of the wheel bearing is completed within the vehicle power unit, the process of tightening with a fastening member when assembling the bearing to the vehicle can be omitted, improving the ease of mounting the bearing to the vehicle.

[0024] In this case, the fit of the mating portion between the inner shaft and the outboard inner ring may be an interference fit, and a relief portion having a smaller diameter than the mating portion between the outboard inner ring and the inner shaft may be provided at the outboard end of the inner shaft.

[0025] In a conventional configuration in which a shaft is inserted into an inner ring and preloaded by fastening with a fastening member, the fit when the shaft is inserted into the inner ring is managed by a loose fit. In this configuration, creep may occur if relative movement such as sliding occurs at the contact area. If creep occurs at the contact area between the inner ring and the shaft, galling may occur, which may lead to a shortened bearing life.

[0026] According to the above configuration, the fit between the outboard side inner ring and the inner ring shaft is an interference fit, thereby preventing the occurrence of creep and preventing deterioration of the wheel support bearing. Also, by providing a relief portion with a smaller diameter than the fit between the outboard side inner ring and the inner ring shaft at the outboard side end of the inner ring shaft, it is possible to prevent interference between the outer diameter portion of the inner ring shaft and the inner diameter portion of the outboard side inner ring during crimping, and the preload of the wheel support bearing can be reliably managed.

[0027] Another aspect of the present invention is a vehicle power unit. a wheel bearing including a fixed ring and a rotating ring rotatably supported by the fixed ring via rolling elements, the rotating ring being provided with a hub flange to which a wheel of a vehicle is attached; A vehicle power unit including a generator having a stator attached to a fixed ring of the wheel bearing and a rotor attached to a rotating ring of the wheel bearing, The stator is attached to an inboard outer peripheral surface of an inner ring shaft of the wheel bearing which is the fixed ring via a stator holding member, a communication hole for leading wiring of the stator coil to the outside is provided on an inboard end surface of the inner ring shaft, A seal member for preventing intrusion of foreign matter into the internal space is provided on the outer diameter surface of the inboard end of the stator holding member.

[0028] Even with this configuration, the wiring coming out of the inboard coil of the generator is led out from the communication hole radially inside the stator, so that space is secured on the inboard side of the stator, and this space can be effectively used for the motor winding coil. As a result, a desired motor output can be obtained. Also, because the communication hole is located radially inside the stator, the diameter of the seal member installed radially outside the communication hole can be made small. This makes it possible to suppress an increase in the seal peripheral speed during wheel rotation, and suppress deterioration of the seal member due to heat generation during high-speed rotation, etc. Effect of the Invention

[0029] According to the vehicle power unit of the present invention, the space occupied by the motor section can be secured to obtain the desired motor output, and the seal can be made smaller in diameter to prevent a decrease in seal life that would otherwise be caused by an increase in the seal peripheral speed during wheel rotation. [Brief description of the drawings]

[0030] [Figure 1] 1 is a vertical cross-sectional view showing a vehicle power unit according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] 2 is a perspective view showing a stator of a generator of the vehicle power plant. FIG. [Figure 4] FIG. [Diagram 5] 4A to 4C are diagrams showing an assembly process for the stator unit of the generator. [Figure 6] FIG. 4 is a vertical sectional view showing a modified example of the vehicle power unit. [Figure 7] FIG. 4 is a vertical sectional view showing another modified example of the vehicle power unit. [Figure 8] 4 is a vertical cross-sectional view showing an example in which a rotation detector is attached to the vehicle power unit. FIG. [Figure 9] 13 is a vertical sectional view showing a modified example in which the rotation detector is attached to the vehicle power unit. FIG. [Figure 10]13 is a vertical sectional view showing another modified example in which the rotation detector is attached to the vehicle power unit. FIG. [Figure 11] 13 is a vertical sectional view showing still another modified example in which the rotation detector is attached to the vehicle power unit. FIG. [Figure 12] FIG. 4 is a vertical sectional view showing a modified example of the vehicle power unit. [Figure 13] 13 is a cross-sectional view taken along line XIII-XIII in FIG. 12. [Figure 14] FIG. 13 is a perspective view showing a stator of the generator of the modified example. [Figure 15] 13 is a cross-sectional view showing a modified example of the stator unit of the generator. FIG. [Figure 16A] FIG. 4 is a vertical sectional view showing another modified example of the vehicle power unit. [Figure 16B] FIG. 16B is an enlarged cross-sectional view showing a portion XVIB of FIG. 16A. [Figure 17] FIG. 5 is a vertical cross-sectional view showing a vehicle power unit according to a second embodiment of the present invention. [Figure 18] 18 is a cross-sectional view taken along line XVIII-XVIII in FIG. 17. [Figure 19] 2 is a perspective view showing a stator of a generator of the vehicle power plant. FIG. [Figure 20] FIG. 4 is a partial cross-sectional view showing a modified example of the vehicle power unit. [Figure 21] FIG. 21 is a cross-sectional view taken along line XXI-XXI in FIG. 20. [Figure 22] FIG. 2 is a vertical cross-sectional view showing a seal member for a vehicle power unit according to each embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] A preferred embodiment of the present invention will be described below with reference to the drawings. In the following description, the terms "axial direction", "radial direction" and "circumferential direction" refer to the "axial direction", "radial direction" and "circumferential direction" of the wheel bearing, respectively. In addition, in the axial direction, when the bearing is attached to the vehicle body, the direction toward the vehicle body centerline extending in the longitudinal direction of the vehicle, i.e., the vehicle body side, is called the "inboard side", and the direction away from the vehicle body centerline, i.e., the wheel side, is called the "outboard side". Furthermore, the radially inner side is called the inner diameter side, and the radially outer side is called the outer diameter side.

[0032] 1 shows a vehicle power unit PU according to a first embodiment of the present invention. The vehicle power unit PU of this embodiment includes a wheel bearing 30 and a generator GE. The wheel bearing 30 includes fixed rings 2, 3 and a rotating ring 1 rotatably supported by the fixed rings 2, 3 via rolling elements 5. In this embodiment, steel balls are used as the rolling elements 5, but the rolling elements 5 are not limited thereto.

[0033] The wheel support bearing 30 of this embodiment is an outer ring rotating type, and has an outer ring 1 which is a rotating ring, and an inner member IM which is a fixed ring. The inner member IM of this embodiment has an inner ring 2 and an inner ring shaft 3 inserted into the hollow part of the inner ring 2. In this embodiment, the inner ring 2 is disposed on the outer periphery of the outboard side of the inner ring shaft 3, and the inner ring shaft 3 is fitted into the inner ring 2 from the inboard side. In this embodiment, the outboard side shaft end of the inner ring shaft 3 is crimped radially outward, thereby applying a preload to the wheel support bearing 30. In other words, the crimped portion 44 of the outboard side end of the inner ring shaft 3 abuts against the outboard side end face of the inner ring 2, suppressing the axial movement of the inner ring 2 and applying a preload to the wheel support bearing 30.

[0034] The fit of the fitting portion between the inner shaft 3 and the outboard inner ring 2 is, for example, an interference fit. In this case, as shown in Fig. 16A and Fig. 16B, a relief portion 50 having a smaller diameter than the fitting portion 49 between the outboard inner ring 2 and the inner shaft 3 may be provided at the outboard end of the inner shaft 3. In other words, the outer diameter dimension D3 of the fitting portion 49 is formed larger than the outer diameter dimension D4 of the relief portion 50 (D3>D4). The relief portion 50 is an annular groove recessed radially inward, and is formed on the outboard side of the fitting portion 49. This makes it easy to crimp the crimp portion 44 in the direction of the arrow Ar. Fig. 16A and Fig. 16B show the state before crimping.

[0035] As shown in FIG. 1, two outer ring rolling surfaces 1a are formed side by side in the axial direction on the inner peripheral surface of the outer ring 1. An outboard side inner ring rolling surface 2a is formed on the outer peripheral surface of the inner ring 2. The outboard side inner ring rolling surface 2a faces the outboard side outer ring rolling surface 1a in the radial direction. An inboard side inner ring rolling surface 3a is formed on the outer peripheral surface of the inner ring shaft 3. The inboard side inner ring rolling surface 3a faces the inboard side outer ring rolling surface 1a in the radial direction. Rolling elements 5 are interposed between the outboard side outer ring rolling surface 1a and the inner ring rolling surface 2a, and between the inboard side outer ring rolling surface 1a and the inner ring rolling surface 3a.

[0036] A flange-shaped hub flange 1b extending radially is provided on the outboard side portion of the outer ring 1. A plurality of bolt insertion holes 1ba are formed in the hub flange 1b at intervals in the circumferential direction. The wheel Wh and the brake rotor 22 are attached to the hub flange 1b of the outer ring 1 by inserting hub bolts 4 into the bolt insertion holes 1ba and tightening them with nuts (not shown). An outer ring cap 6 is fitted to the inner peripheral surface of the outboard end of the outer ring 1, closing the outboard side of the wheel bearing 30.

[0037] A large-diameter flange portion 3c is formed at the inboard end of the inner shaft 3, and a plurality of female threads 21 are provided on the flange portion 3c. In this embodiment, as shown in Fig. 2, six female threads 21 are provided, but the number of female threads 21 is not limited to this. The inner shaft 3 is attached to a suspension part of the vehicle, i.e., a suspension device 19, by fastening a bolt 18 shown in Fig. 1 to the female threads 21. In other words, the wheel bearing 30 is attached to the suspension device 19 of the vehicle by the bolt 18.

[0038] The radial position of the axis X1 of the bolt 18 is substantially the same as the radial position of the center O1 of the rolling element 5. Here, "the radial position of the axis X1 of the bolt 18" refers to the radial distance D1 between the axis AX of the wheel support bearing 30 and the axis X1 of the bolt 18. Meanwhile, "the radial position of the center O1 of the rolling element 5" refers to the radial distance D2 between the axis AX of the wheel support bearing 30 and the center O1 of the rolling element 5. In this embodiment, the radial positions of the axis X1 of the bolt 18 and the center O1 of the rolling element 5 are substantially the same (D1=D2), but the radial position of the axis X1 of the bolt 18 may be located radially inward relative to the radial position of the center O1 of the rolling element 5 (D1 <D2)。

[0039] The generator GE is supported by the wheel bearing 30, and generates a driving force and a regenerative braking force. The generator GE has a stator 9 attached to the fixed wheel 3 of the wheel bearing 30, and a rotor 12 attached to the rotating wheel 1 of the wheel bearing 30. The generator GE is installed in the brake rotor 22 while being supported by the wheel bearing 30.

[0040] In detail, the brake rotor 22 has an annular supported portion 22a, a cylindrical portion 22b extending axially from the radial outer end of the supported portion 22a toward the inboard side, and a gripped portion 22c extending radially outward from the inboard end of the cylindrical portion 22b. The supported portion 22a is flat and is clamped and bolted between the flange portion 1a of the outer ring 1 and the wheel Wh. The gripped portion 22c constitutes the brake sliding portion 22c, which is a portion of the brake rotor 22 against which a brake caliper (not shown) is pressed. The generator GE is disposed radially inside the cylindrical portion 22b and the brake sliding portion 22c of the brake rotor 22.

[0041] A stator bracket 17 is attached to the outer periphery of the inner shaft 3. The stator bracket 17 has an annular portion 17a at the inboard end and a cylindrical portion 17b extending axially from the annular portion 17a to the outboard side. The inner peripheral surface of the annular portion 17a is fitted into the outer peripheral surface of the flange portion 3c of the inner shaft 3.

[0042] The stator 9 is attached to the stator bracket 17. The stator 9 has a cylindrical stator core 7 and a winding coil 8 for generating a magnetic force by passing a current through it. The winding coil 8 is attached to the stator core 7. The inner peripheral surface of the stator core 7 is fitted into the outer peripheral surface of a cylindrical portion 17b of the stator bracket 17. In other words, the stator 9 is attached to the inboard end of the inner ring shaft 3 via the stator bracket 17. The stator bracket 17 constitutes a stator holding member 17 that holds the stator 9 on the inner ring shaft 3.

[0043] A cylindrical rotor case 13 is attached by press fitting to the outer periphery of the hub flange 1a of the outer ring 1. In detail, the inner periphery of a fitting portion 13a at the outboard end of the rotor case 13 is fitted to the outer periphery of the hub flange 1a of the outer ring 1. The rotor 12 is attached to the inner periphery of a cylindrical portion 13b extending axially from the fitting portion 13a toward the inboard side. The rotor 12 has a rotor core 11 and permanent magnets 10, and is disposed radially outward of the stator 9 so as to face the stator 9 in the radial direction.

[0044] In this embodiment, the rotor case 13 has a bottom portion 13c extending radially inward from the fitting portion 13a, and the bottom portion 13c is sandwiched between the hub flange 1a of the outer ring 1 and the supported portion 22a of the brake rotor 22 and fastened together by the hub bolt 4. However, if sufficient support strength can be ensured, the bottom portion 13c may be omitted.

[0045] The generator GE of this embodiment is accommodated radially inward of the brake sliding portion 22c of the brake rotor 22. Since the generator GE is disposed radially inward of the brake rotor 22 in this manner, when the generator GE is mounted on a vehicle, the mechanical structure from the generator GE to the axle AX is minimized, and an increase in weight can be suppressed. In this embodiment, the entire stator 9 and rotor 12 are configured to have a smaller diameter than the brake sliding portion 22c of the brake rotor 22, but it is sufficient that the stator 9 and part of the rotor 12 have a smaller diameter than the brake sliding portion 22c.

[0046] In addition, the entire generator GE, except for the mounting portion (fitting portion 13a and bottom portion 13c) to the hub flange 1a, is located in the axial range between the hub flange 1a and the outboard side of the vehicle suspension device 19 (suspension frame part).

[0047] Further, a seal unit 33 is press-fitted between the inner peripheral surface of the inboard end of the rotor case 13 and the outer peripheral surface of the inboard end of the stator bracket 17. In other words, the inboard end of the wheel bearing 30 is closed by the seal unit 33. The seal unit 33 has a seal holder 15 and a seal member 16.

[0048] The seal holder 15 is press-fitted into the inner circumferential surface of the inboard end of the rotor case 13 to close the inboard end of the wheel bearing 30. In detail, the seal holder 15 has an annular cover portion 15a that closes the inboard end of the wheel bearing 30, and a cylindrical fitting portion 15b that is press-fitted into the inner circumferential surface of the inboard end of the rotor case 13. The fitting portion 15b extends in the axial direction from the radially outer end of the cover portion 15a toward the outboard side.

[0049] A seal member 16 is interposed between the inner diameter surface of the cover portion 15a of the seal holder 15 and the outer diameter surface of the inboard end of the stator holding member 17. The seal member 16 prevents water, oil, etc. from entering the motor installation space inside the bearing from the external environment, and also prevents leakage of lubricant (bearing grease) etc. sealed in the wheel bearing 30.

[0050] As shown enlarged in Fig. 22, the seal member 16 of this embodiment has an annular slinger 60 and an annular seal plate 62 arranged to face each other in the radial direction. The slinger 60 is made of a ferromagnetic steel plate. Specifically, the slinger 60 is, for example, a ferritic stainless steel plate (such as SUS430 of the JIS (Japanese Industrial Standards)) or a rust-proofed cold-rolled steel plate. However, the material of the slinger 60 is not limited to this.

[0051] In this embodiment, the slinger 60 is formed by pressing a steel plate so that its cross section is substantially L-shaped. In detail, the slinger 60 has a slinger cylindrical portion 60a that is press-fitted into the outer diameter surface of the stator holding member 17, and a slinger standing plate portion 60b that extends radially outward from the slinger cylindrical portion 60a. In this embodiment, the slinger 60 is press-fitted into the stator holding member 17 so that the slinger standing plate portion 60b is located on the inboard side.

[0052] The seal plate 62 has a core metal 64 fitted to the inner peripheral surface of the seal holder 15 and an elastic member 66 integrally joined to the core metal 64 by vulcanization adhesion. The core metal 64 is made of, for example, an austenitic stainless steel plate or a rust-proofed cold-rolled steel plate. However, the material of the core metal 64 is not limited to this. The core metal 64 is formed into a substantially L-shaped cross section by pressing a steel plate. In detail, the core metal 64 has a seal plate cylindrical portion 64a press-fitted into the inner diameter surface of the seal holder 15 and a seal plate standing portion 64b extending radially inward from the seal plate cylindrical portion 64a. In this embodiment, the seal plate 62 is press-fitted into the seal holder 15 so that the seal plate standing portion 64b is located on the outboard side.

[0053] The elastic member 66 is made of synthetic rubber such as nitrile rubber (NBR). The material of the elastic member 66 is not limited to NBR, and may be, for example, hydrogenated nitrile rubber (HNBR), ethylene propylene diene rubber (EPDM), acrylic rubber (ACM), fluororubber (FKM), silicone rubber, etc., which have excellent heat resistance. HNBR and EPDM have excellent heat resistance, while ACM and FKM have excellent heat resistance and chemical resistance.

[0054] In this embodiment, the elastic member 66 is mostly bonded to the inboard side of the seal plate upright portion 64b on the inner diameter side of the seal plate cylindrical portion 64a. The elastic member 66 has a side lip 66a, a dust lip 66b, and a grease lip 66c.

[0055] The side lip 66a extends from the vicinity of the tip of the sealing plate standing portion 64b (the vicinity of the radially inner end portion) toward the inboard side, inclining radially outward. The tip of the side lip 66a is in sliding contact with the standing portion 60b of the slinger 60 with a predetermined axial gap therebetween.

[0056] The strip 66b and the grease lip 66c are located on the inner diameter side of the side lip 66a and extend radially inward in a bifurcated manner from near the tip of the seal plate standing portion 64b. In detail, the dust lip 66b and the grease lip 66c are arranged side by side in the axial direction, with the dust lip 66b on the inboard side and the grease lip 66c on the outboard side. The dust lip 66b and the grease lip 66c are in sliding contact with the cylindrical portion 60a of the slinger 60 with a predetermined radial gap therebetween.

[0057] In this manner, in this embodiment, the seal lip slides on the inner diameter side. Since the inner diameter ends of the dust lip 66b and the grease lip 66c are in contact with each other, the circumferential speed of the contact portion can be reduced. In addition, the side lip 66a, the dust lip 66b, and the grease lip 66c are in sliding contact with the slinger 60, and are not in contact with the stator holding member 17. Therefore, there is no need to subject the stator holding member 17 to a treatment such as polishing, and the maintenance requires only replacing the slinger 60. However, the slinger 60 may be omitted, and each lip 66a, 66b, and 66c may be in direct sliding contact with the outer diameter surface of the stator holding member 17.

[0058] Although not shown, the gap between the rotor case 13 and the outer ring 1, and the gap between the rotor case 13 and the seal holder 15 are sealed with O-rings or the like to prevent the intrusion of dirt, oil, etc., and to prevent leakage of the lubricant (bearing grease) sealed in the wheel bearing 30.

[0059] [Removing the generator power line] 1, a bus bar 14 is provided on the inboard end face of the stator core 8. The bus bar 14 is a conductor rod that connects a power source to the coil 8. A plurality of bus bars 14 are provided at the radially outer end of the inboard end face of the stator core 8, spaced apart in the circumferential direction, and protrude to the inboard side.

[0060] A power line 20 is connected to the bus bar 14. The power line 20 supplies power to the coil 8 of the stator 9 via the bus bar 14. In other words, the power line 20 constitutes the wiring 20 of the coil 8 of the stator 9. The power line 20 extends radially inward from the bus bar 14 to a position inside the inner diameter surface of the stator 9, and then extends in the axial direction toward the inboard side and is led out to the outside.

[0061] In detail, a communication hole 25 facing the axial direction is provided in a portion of the inboard end face of the stator holding member 17 that is radially inward from the stator 9. The wiring (power line) 20 of the coil 8 of the stator 9 is led out to the outside through this communication hole 25. As shown in Fig. 3, the communication hole 25 in this embodiment is a groove-shaped through hole that is formed in the inboard end face of the stator holding member 17 and extends in the circumferential direction.

[0062] In this way, by taking the power line 20 out from the communication hole 25 radially inside the stator 9, the space on the inboard side of the busbar 14 is increased, and the winding coil 8 can be wound more, thereby increasing the output of the generator (motor).

[0063] Also, by providing the communication hole 25 radially inward from the stator 9, the diameter of the seal member 16 attached to the outer diameter surface of the inboard end of the stator holding member 17 shown in Fig. 1 can be reduced. Furthermore, since the radial position of the axis X1 of the bolt 18 for mounting to the vehicle body is approximately the same as the radial position of the center O1 of the rolling element 5, the diameter of the seal member 16 can be further reduced. As a result, the seal peripheral speed during wheel rotation is reduced, and the seal member 16 is expected to have a longer life.

[0064] In the above structure, the bus bar 14 is provided on the winding coil 8, and the power line 20 is taken out via the bus bar 14, but the power line 20 may be taken out directly from the winding coil 8 to the inner diameter side. In this case, the same effect can be obtained.

[0065] [Assembly of vehicle power unit] An exploded structural view of the vehicle power unit PU of this embodiment is shown in Fig. 4. As shown in the figure, the vehicle power unit PU of this embodiment is composed of a wheel bearing 30, a rotor unit 31, a stator unit 32, and a seal unit 33.

[0066] The rotor unit 31 has a rotor case 13 and a rotor 12 housed therein. The stator unit 32 has a stator holding member 17 and a stator 9 held therein. The seal unit 33 has a seal holder 15 and a seal member 16 fitted to the inner diameter surface thereof.

[0067] 5 shows the assembly process of stator unit 32. As described above, stator unit 32 has stator holding member 17 and stator 9 (step (A)). Stator 9, busbar 14, and power line 20 have an integral structure. Notches 45 are formed in the outer circumferential surface of stator holding member 17 at circumferential positions corresponding to communication holes 25.

[0068] As shown in step (B), the stator 9 is attached to the stator holding member 17. More specifically, the outer peripheral surface of the stator holding member 17 is fitted to the inner peripheral surface of the stator 9. At this time, the power lines 20 protrude toward the inner diameter side and extend in the axial direction, but pass radially through the notches 45 of the stator holding member 17 and are taken out axially from the communication holes 25 of the stator holding member 17. Therefore, the stator 9 can be attached to the stator holding member 17 without any problems. With the above, the stator unit 32 is completed (step (C)).

[0069] As shown in a modified example of FIG. 15, a resin member 38 having good thermal conductivity may be filled in gaps between the stator core 7 and the winding coil 8, and between the stator core 7 and the busbar 14, etc. The resin member 38 is shown by cross-hatching in FIG. 15. In order to improve heat dissipation, it is preferable to mold the stator 9 with a thermosetting resin having a thermal conductivity of 1 (W / mK) or more. Examples of thermosetting resins having a thermal conductivity of 1 (W / mK) or more include epoxy resin and phenolic resin. In addition, by mixing boron nitride (BN), aluminum oxide (AL2O3), etc. as a filler (additive) into the resin member 38, the thermal conductivity can be further increased and the heat dissipation can be improved.

[0070] Filling with such resin member 38 allows heat generated in the winding coil 8 to be efficiently released to the outside, contributing to improved motor performance and preventing damage to the winding coil 8 during assembly. Filling with such resin member 38 may be performed on the integrated structure of stator 9 and busbar 14 (step (A)), or may be performed on the completed state of stator unit 32 in which the integrated structure of stator 9 and busbar 14 is assembled into stator bracket 17 (step (C)).

[0071] As shown in Fig. 4, the inner peripheral surface of the stator holding member 17 of the stator unit 32 is fitted onto the outer peripheral surface of the inner ring shaft 3 of the wheel support bearing 30. This completes the assembly of the wheel support bearing 30 and the stator unit 32. Also, the inner peripheral surface of the rotor case 13 of the rotor unit 31 is fitted onto the outer peripheral surface of the hub flange 1b of the outer ring 1 of the wheel support bearing 30, and the hub flange 1b and the rotor unit 31 are connected by the hub bolts 4. This completes the assembly of the wheel support bearing 30 and the rotor unit 31.

[0072] Next, the outer peripheral surface of the seal holder 15 of the seal unit 33 is attached to the inner peripheral surface of the rotor case 13 of the rotor unit 31. At this time, the seal member 16 is held between the outer peripheral surface of the stator holding member 17 of the stator unit 32 and the inner peripheral surface of the seal holder 15 of the seal unit 33. In this way, the vehicle power unit PU is assembled.

[0073] Finally, the vehicle power unit PU is fixed to the vehicle suspension 19 by bolts 18. The vehicle power unit PU can be removed from the suspension 19 and disassembled by reversing the above steps. In this manner, the vehicle power unit PU in this embodiment has a structure that allows easy disassembly and assembly.

[0074] FIG. 6 shows a modified example of the vehicle power unit of this embodiment. In the example of FIG. 6, the mounting structure of the vehicle power unit PU to the suspension 19 is different from that of the example of FIG. 1. Specifically, the suspension 19 is provided with a protrusion 36 that protrudes to the inboard side via a step portion 36a, and a protrusion 3b that fits into the step portion 36a is formed at the inboard end of the inner shaft 3. A bolt fixing screw hole (female thread) 21 is formed on the outboard end face of the protrusion 3b. In this embodiment, the central axis of the protrusion 36 and the protrusion 3b coincides with the central axis AX of the wheel bearing 30.

[0075] The inner shaft is fastened to the suspension 19 by pressing the convex portion 3b of the inner shaft 3 against the step portion 36a of the protrusion 36 of the suspension 19 and tightening the bolt 37 into the bolt fixing threaded hole 21 of the inner shaft 3. According to this example, the axis of the inner shaft 3 can be fastened with a large diameter bolt 37, so the suspension 19 and the inner shaft 3 can be fixed with a large axial force. Also, there is no need to fix with multiple bolts 18 as in the example of Figure 1, making installation easier.

[0076] Fig. 7 shows another modified example of the vehicle power unit of this embodiment. The example of Fig. 7 also differs from the examples of Figs. 1 and 6 in the mounting structure of the vehicle power unit PU to the suspension device 19. Specifically, a through hole 41 facing the axial direction is provided in the suspension device 19, and a male thread portion 29 protruding to the inboard side is provided on the inboard side surface of the inner shaft 3. In this embodiment, the central axes of the through hole 41 and the male thread portion 29 coincide with the central axis AX of the wheel bearing 30.

[0077] The male thread portion 29 of the inner shaft 3 is inserted into a through hole 41 of the suspension device 19, and the nut 28 is tightened onto the male thread portion 29, thereby fixing the inner shaft 3 to the suspension device 19. According to this example, there is no need to fix with multiple bolts 18 as in the example of Figure 1, and installation is easier.

[0078] [Rotation detector] 8 shows an example in which a rotation detector RD is attached to a vehicle power unit of this embodiment. The rotation detector RD detects at least one of the rotation angle and rotation speed of the rotating wheel 1 relative to the fixed wheel 3. Specifically, the rotation detector RD has a target 23 fixed to the rotating wheel 1, and a sensing unit 24 fixed to the fixed wheel 3 for detecting the target 23. In this embodiment, the rotation detector RD is located radially inward of the rotor 12.

[0079] In this embodiment, a target 23 of the rotation detector RD is installed on the outer race cap 6 that closes the outboard end of the outer race 1, which is a rotating race, and a sensing unit 24 of the rotation detector RD is installed on the outboard end face of the inner race shaft 3, which is a fixed race. The target 23 and the sensing unit 24 are attached to the outer race cap 6 and the outboard end face of the inner race shaft 3, respectively, by adhesive means, for example. The target 23 and the sensing unit 24 are installed with a predetermined gap secured in the axial direction.

[0080] A hollow hole 40 is formed in the inner shaft 3. The hollow hole 40 is a through hole 40 that passes through the inner shaft 3 in the axial direction. In this embodiment, the axis of the hollow hole 40 coincides with the center axis AX of the wheel bearing 30. The power supply and signal line LN of the rotation detector RD are taken out to the outside through the hollow hole 40 of the inner shaft 3.

[0081] 9 shows another example of mounting the rotation detector RD in the vehicle power plant of this embodiment. In this example, a target 26 of the rotation detector RD is mounted on the outer periphery of the outer ring 1, which is a rotating ring, and a sensing unit 27 of the rotation detector RD is mounted on the outboard end face of the stator holding member 17. The target 26 is mounted on the outer periphery of the outer ring 1 by, for example, press fitting. The sensing unit 27 is mounted on the outboard end face of the stator holding member (stator bracket) 17 by, for example, adhesive means.

[0082] 10 shows yet another example of mounting the rotation detector RD in the vehicle power plant of this embodiment. In this example, a target 34 of the rotation detector RD is mounted on the seal holder 15 attached to the outer ring, and a sensing unit 35 of the rotation detector RD is mounted on the stator holding member 17. The target 34 is mounted on a surface facing the outboard side of the seal holder 15. A radially extending annular portion 46 is formed on the outboard side of the stator holding member (stator bracket) 17, and a sensing unit 35 is mounted on a surface of the annular portion 46 facing outboard. The target 34 and the sensing unit 35 are mounted to the seal holder 15 and the annular portion 46, respectively, by, for example, adhesive means.

[0083] 11 shows yet another mounting example of the rotation detector RD in the vehicle power plant of this embodiment. In this example, a target 34A of the rotation detector RD is mounted on the outer periphery of the inboard side portion of the outer ring 1, which is a rotating ring, and a sensing unit 35A of the rotation detector RD is mounted on the stator holding member 17. The target 34A is mounted on the outer periphery of the inboard side portion of the outer ring 1, for example, by press fitting. Meanwhile, the sensing unit 35A is mounted on the inner periphery of the inboard side of the stator bracket (stator holding member) 17, by press fitting. The target 34A and the sensing unit 35A are disposed opposite each other with a predetermined gap secured in the axial direction.

[0084] Another example of the vehicle power plant of this embodiment is shown in Figures 12 to 14. Figure 12 is a cross-sectional view of the vehicle power plant, Figure 13 is a cross-sectional view taken along line XIII-XIII in Figure 12, and Figure 14 is a perspective view of a stator 9 of the vehicle power plant.

[0085] In this example, the wheel support bearing 30 is attached to the suspension 19 by the bolts 18 via the stator bracket 17. The stator bracket 17 in this example has a flat plate portion 48 that is sandwiched between the inboard end face of the inner shaft 3 and the outboard end face of the suspension 19. A bolt insertion hole 48a is formed in the flat plate portion 48 at a position corresponding to the bolt fixing screw hole 21 of the inner shaft 3. With the flat plate portion 48 of the stator bracket 17 sandwiched between the inboard end face of the inner shaft 3 and the outboard end face of the suspension 19, the bolt 18 is inserted through the bolt insertion hole 48a from the inboard side and tightened into the bolt fixing screw hole 21 of the inner shaft 3, thereby attaching the wheel support bearing 30 to the suspension 19 via the stator bracket 17.

[0086] In this example as well, it is possible to reduce the diameter of the seal member 18, as in the example of Fig. 1. Furthermore, the stator bracket 17 is fixed to the suspension device 19 with bolts (not shown), so that only the wheel support bearing 30 can be easily disassembled from the suspension device 19 during maintenance of the wheel support bearing 30.

[0087] According to the above configuration, the wiring 20 coming out from the coil 8 on the inboard side of the generator GE shown in FIG. 1 is led out from the communication hole 25 located radially inward of the stator 9. In other words, the wiring 20 extends radially inward from the stator 9 and is then led out to the inboard side. This ensures space on the inboard side of the stator 9, and this space can be effectively used for the motor winding coil 8. As a result, the desired motor output can be obtained.

[0088] In addition, the wheel support bearing 30 is of an outer ring rotating type, and the inner ring shaft 3, which is a fixed ring, is connected to the vehicle body by a bolt 18. In other words, the bolt 18 is located radially inward and close to the axis AX of the wheel support bearing 30. Therefore, the diameter of the seal member 16 can be made small.

[0089] Furthermore, the communication hole 25 through which the wiring 20 of the generator GE is led out to the outside is located radially inward of the stator 9. In other words, the communication hole 25 is disposed on the inner diameter side closer to the axis AX of the wheel bearing 30. This makes it possible to reduce the diameter of the seal member 16 that is installed radially outward of the communication hole 25. This makes it possible to suppress an increase in the circumferential speed of the seal member 16 during wheel rotation, and suppresses deterioration of the seal member 16 due to heat generation during high-speed rotation, etc.

[0090] The inner shaft 3 is attached to a vehicle suspension 19 by a bolt 18, and a radial position D1 of the axis of the bolt 18 is the same as a radial position D2 of the center O1 of the rolling element 5 or is located on the inner diameter side. With this configuration, the bolt 18 is located radially inward and close to the axis AX of the wheel bearing 30. Therefore, the diameter of the seal member 16 can be made small, so that an increase in the circumferential speed of the seal member 16 during wheel rotation can be suppressed, and deterioration of the seal member 16 due to heat generation during high-speed rotation can be suppressed.

[0091] The stator 9 and rotor 12 have a smaller diameter than the portion of the brake rotor 22 against which the brake caliper is pressed, and the entire generator GE, except for the portion attached to the hub flange 1b, is located in the axial range between the hub flange 1b and the outboard side surface of the vehicle suspension frame component (suspension device) 19. This configuration allows the vehicle power unit PU, including the stator 9 and rotor 12 of the generator GE, to be arranged compactly. Furthermore, since the rotation detector RD is located radially inward of the rotor 12, the rotation detector RD can also be arranged compactly.

[0092] As shown in Fig. 6, the inner shaft 3 may be provided with a female thread 21 on the inboard end face thereof, and the inner shaft 3 may be attached to the vehicle suspension 19 by fastening a bolt 37 to the female thread 21. Alternatively, as shown in Fig. 7, the inner shaft 3 may be provided with a male thread portion 29 protruding from the inboard end face thereof, and the inner shaft 3 may be attached to the vehicle suspension 19 by fastening a nut 28 to the male thread portion 29.

[0093] 6 and 7, the bolts 37 or nuts 28 are located radially inward and close to the axis AX of the wheel bearing 30. This allows the diameter of the seal member 16 to be reduced, thereby preventing an increase in the circumferential speed of the seal member 16 during wheel rotation and preventing deterioration of the seal member 16 due to heat generation during high-speed rotation.

[0094] 8, a target 23 of the rotation detector RD may be provided on the outer race cap 6, a sensing portion 24 of the rotation detector RD may be provided on the outboard end face of the inner race shaft 3, and a through hole 40 for leading out a signal line LN of the rotation detector RD may be provided in the inner race shaft 3. Also, as shown in FIG. 9, a target 26 of the rotation detector RD may be provided on the outer periphery of the outer race 1, and a sensing portion 27 of the rotation detector RD may be provided on the outboard end face of the stator holding member 17.

[0095] 10, a target 34 of the rotation detector RD may be provided on the seal holder 15, and a sensing portion 35 of the rotation detector RD may be provided on the stator holding member 17. Alternatively, as shown in Fig. 11, a target 34A of the rotation detector RD may be provided on the outer periphery of the inboard portion of the outer ring 1, and a sensing portion 35A of the rotation detector RD may be provided on the inner periphery of the inboard portion of the stator holding member 17.

[0096] The rotation detector RD can be arranged compactly on the wheel support bearing 30 by any of the arrangements of the targets 23, 26, 34, 34A and the sensing portions 24, 27, 35, 35A in FIGS.

[0097] As shown in FIG. 1, an outboard side inner ring 2 is disposed on the outer periphery of the outboard side of the inner ring shaft 3, the inner ring shaft 3 is fitted into the outboard side inner ring 2 from the inboard side, and the outboard side shaft end 44 of the inner ring shaft 3 is crimped radially outward.

[0098] According to this configuration, the inner ring shaft 3 is fitted from the inboard side to the inner ring 2 on the outboard side, and the outboard side shaft end 44 of the inner ring shaft 3 is crimped radially outward to apply a preload. This allows the preload on the wheel bearing with power generation function to be properly managed without using a nut. By properly managing the preload, the desired fastening force is maintained and it is possible to prevent the nut from loosening due to vibration during driving. Furthermore, since the preload management of the wheel bearing is completed within the vehicle power unit, the process of tightening with a nut when assembling it to the vehicle can be omitted, improving the ease of installation on the vehicle.

[0099] Also, by using an interference fit between the outboard side inner ring 2 and the inner ring shaft 3, it is possible to prevent creep and deterioration of the wheel support bearing 30. Furthermore, as shown in Figures 16A and 16B, by providing a relief portion 50 with a smaller diameter than the fitting portion 48 between the outboard side inner ring 2 and the inner ring shaft 3 at the outboard side end of the inner ring shaft 3, it is possible to prevent interference between the outer diameter portion of the inner ring shaft 3 and the inner diameter portion of the outboard side inner ring 2 during crimping, and it is possible to reliably manage the preload of the wheel support bearing.

[0100] A vehicle power unit PU according to a second embodiment of the present invention is shown in Fig. 17 to Fig. 19. Fig. 17 is a cross-sectional view of the vehicle power unit, Fig. 18 is a cross-sectional view taken along line XVIII-XVIII in Fig. 17, and Fig. 19 is a perspective view of a stator 9 of a generator GE of the vehicle power unit. In the following description, the same components as those in the first embodiment are given the same reference symbols, and detailed description thereof will be omitted.

[0101] In the second embodiment, a communication hole 39 for leading out the wiring 20 of the coil 8 of the stator 9 to the outside is provided in the inner shaft 3, not in the stator holding member 17. That is, the communication hole 39 for leading out the wiring 20 of the coil 8 to the outside is provided in the inboard end face of the inner shaft 3.

[0102] In detail, of the bolt fixing threaded holes 21 for attaching the inner shaft 3 to the suspension device 19, the bolt fixing threaded hole 21 at the portion where the bus bar 14 is taken out has been removed, and instead a communication hole 39 is provided at one location on the circumference on the inboard side of the inner shaft 3. The motor power line 20 is taken out to the outside via this communication hole 39.

[0103] In this embodiment, all but one of the six bolt fixing screw holes 21 arranged at equal intervals in the circumferential direction are provided with a communication hole 39. However, the number and arrangement of the communication holes 39 are not limited to this embodiment, and the size, number, and positions of the bolt fixing screw holes 21 and the positions of the communication hole 39 in the inner shaft 3 are not important as long as the strength is allowed.

[0104] A cutout portion 45 is formed at a position corresponding to the communication hole 39 in the outer diameter portion of the inner ring shaft 3. Also, a through hole 47 is formed at a position corresponding to the cutout portion 45 in the stator holding member 17. Here, "the position corresponding to the communication hole 39" and "the position corresponding to the cutout portion 45" refer to the fact that the circumferential position coincides with the communication hole 39 / the cutout portion 45, respectively. The cutout portion 45 is formed recessed radially inward and communicates with the communication hole 39. The through hole 47 penetrates the stator holding member 17 in the radial direction and communicates with the cutout portion 45. That is, the wiring (motor power line) 20 of the coil 8 of the stator 9 is discharged from the through hole 47 through the cutout portion 45 to the outside from the communication hole 39.

[0105] Also in the second embodiment, the wiring 20 coming out from the coil 8 on the inboard side of the generator GE is led to the outside through the communication hole 39 located radially inside the stator 9, so that space is secured on the inboard side of the stator 9, and this space can be effectively used for the motor winding coil 8. As a result, the desired motor output can be obtained.

[0106] Furthermore, according to the second embodiment, a communication hole 39 is provided on the outer diameter part of the inner shaft 3 to take out the motor power line 20. This makes it possible to reduce the diameter of the seal member 16 that is disposed radially outward of the communication hole 39. As a result, the circumferential speed of the seal member 16 during wheel rotation is reduced, suppressing deterioration of the seal member 16 due to heat generation during high-speed rotation, and is expected to extend the life of the seal member 16.

[0107] Also, similarly to the first embodiment, if the radial distance D1 between the axis AX of the wheel bearing 30 and the axis X1 of the bolt 18 is set to a position that axially overlaps with the radial position D2 of the center O1 of the rolling element 5 or is located radially inward from that position, the diameter of the seal member 16 can be further reduced. As a result, the circumferential speed of the seal member 16 during wheel rotation is reduced, and the seal member 16 can be expected to have a longer life.

[0108] 20 and 21 show a modified example of the vehicle power unit PU according to the second embodiment. The wheel support bearing 30 of this modified example has an outboard side inner ring 2A arranged on the outer diameter surface on the outboard side of the inner ring shaft 3, and an inboard side inner ring 2B arranged on the outer diameter surface on the inboard side of the inner ring shaft 3. Inner ring rolling surfaces 2Aa, 2Ba are formed on the outer diameter surfaces of the outboard side and inboard side inner rings 2A, 2B, and rolling elements 5 are interposed between the outer ring rolling surfaces 1a, 1a of the outer ring 1 and each of the inner ring rolling surfaces 2Aa, 2Ba. In other words, the wheel support bearing 30 of FIGS. 20 and 21 is a so-called "second generation hub bearing."

[0109] The inner ring shaft 3 is fitted from the inboard side to the outboard side and the inboard side inner rings 2A, 2B, and the outboard side shaft end 44 of the inner ring shaft 3 is crimped radially outward. This applies a preload to the wheel bearing 30. The stator bracket (stator holding portion) 17 in Figs. 20 and 21 has a flat plate portion 48 shown in the example in Fig. 12.

[0110] The fit of the fit portion between the inner shaft 3 and the outboard side inner ring 2A is, for example, an interference fit. In this example, too, a relief portion 50 (FIG. 16B) having a smaller diameter than the fit portion 49 between the outboard side inner ring 2A and the inner shaft 3 may be provided at the outboard side end of the inner shaft 3. Also, while FIGS. 20 and 21 show an example in which a second-generation hub bearing is applied to the vehicle power unit PU of the second embodiment in which the communication hole 39 is formed in the inner shaft 3, a second-generation hub bearing may also be applied to the vehicle power unit PU of the first embodiment in which the communication hole 25 is formed in the stator holding member 17.

[0111] In this modified example, the preload on the wheel support bearing with power generation function can be appropriately managed without using a nut, the desired fastening force can be maintained, and loosening of the nut due to vibration during driving can be prevented. Since the preload management of the wheel support bearing is completed within the vehicle power unit, the process of tightening with a nut when assembling it to the vehicle can be omitted, improving the ease of installation on the vehicle.

[0112] The present invention is not limited to the above-described embodiment, and various additions, modifications, and deletions are possible without departing from the scope of the present invention. Therefore, such modifications are also included in the scope of the present invention. [Explanation of symbols]

[0113] 1. Outer ring (rotating ring) of wheel bearing 1b Hub flange 2. Inner ring of wheel bearing (fixed ring) 2A Outboard side inner ring 2B Inboard side inner ring 3. Inner ring shaft of wheel bearing (fixed ring) 3c Flange part 5 Steel ball (rolling element) 6 Outer race cap 9 Stator 12 Rotor 15 Seal holder 16 Sealing material 17 Stator bracket (stator holding member) 18.37 Volts 19 Vehicle suspension system (suspension frame parts) 20 Power line (stator coil wiring) 21 Bolt fixing screw hole (female thread (flange part)) 22 Brake rotor 22c Brake sliding part (part against which the brake caliper is pressed) 23,26,34.34A Rotation Detector Target 24, 27, 35, 35A Sensing part of rotation detector 25,39 Communication hole 28 Nut 29 Male thread (male thread part) 30 Wheel bearings 40 Through hole (hollow hole) 44 Fastening part 50 Relief GE Generators LN Rotation detector signal line PU Vehicle power unit RD Rotation Detector Wh Wheels

Claims

1. a wheel bearing including a fixed ring and a rotating ring rotatably supported by the fixed ring via rolling elements, the rotating ring being provided with a hub flange to which a wheel of a vehicle is attached; A vehicle power unit including a generator having a stator attached to a fixed ring of the wheel bearing and a rotor attached to a rotating ring of the wheel bearing, The stator is attached to an inboard outer peripheral surface of an inner ring shaft of the wheel bearing which is the fixed ring via a stator holding member, a communication hole for leading out wiring of the coil of the stator to the outside is provided at a portion radially inward from the stator in an inboard end face of the stator holding member, A seal member for preventing intrusion of foreign matter into an internal space is provided on an outer diameter surface of the inboard end of the stator holding member.

2. 2. The vehicle power unit according to claim 1, wherein the inner shaft is attached to a suspension of the vehicle by a bolt, A power device for a vehicle, wherein the radial position of the axis of the bolt is the same as the radial position of the center of the rolling element or is located on the inner diameter side.

3. 3. The vehicle power unit according to claim 1, further comprising a rotation detector for detecting a rotation angle or a rotation speed of the rotating wheel relative to the fixed wheel, A brake rotor is attached to the hub flange, a part or whole of the stator and the rotor has a smaller diameter than a portion of the brake rotor against which a brake caliper is pressed; the entire generator, except for a portion attached to the hub flange, is located in an axial range between the hub flange and an outboard side surface of an undercarriage frame component of the vehicle; The vehicle power plant, wherein the rotation detector is located radially inward of the rotor.

4. 3. The vehicle power unit according to claim 1, wherein a plurality of female threads are provided in a flange portion of an inboard end portion of the inner ring shaft, The inner shaft is attached to a suspension system of the vehicle by fastening a bolt to the female thread.

5. 3. The vehicle power unit according to claim 1, wherein a female thread is provided on an inboard end surface of the inner ring shaft, The inner shaft is attached to a suspension system of the vehicle by fastening a bolt to the female thread.

6. 3. The vehicle power unit according to claim 1, wherein a male thread is provided protruding from an inboard end surface of the inner ring shaft, The inner shaft is attached to a suspension system of the vehicle by tightening a nut onto the male thread.

7. 3. The vehicle power unit according to claim 1, further comprising a rotation detector for detecting at least one of a rotation angle and a rotation speed of the rotating wheel relative to the fixed wheel, The target of the rotation detector is installed in an outer ring cap that closes an outboard end of the outer ring, which is the rotating ring; a sensing portion of the rotation detector is provided on an outboard end surface of the inner ring shaft; The vehicle power unit has an inner ring shaft provided with a through hole for leading out a signal line of the rotation detector.

8. 3. The vehicle power unit according to claim 1, further comprising a rotation detector for detecting at least one of a rotation angle and a rotation speed of the rotating wheel relative to the fixed wheel, A target of the rotation detector is installed on the outer periphery of the outer ring, which is the rotating ring; A vehicle power plant, wherein a sensing portion of the rotation detector is disposed on an outboard end face of the stator holding member.

9. 3. The vehicle power unit according to claim 1, further comprising a rotation detector for detecting at least one of a rotation angle and a rotation speed of the rotating wheel relative to the fixed wheel, a target of the rotation detector is installed in a seal holder that is attached to an outer wheel, which is the rotating wheel, and closes an inboard end of a vehicle power plant; A power plant for a vehicle, wherein the sensing portion of the rotation detector is disposed on the stator holding member.

10. 3. The vehicle power unit according to claim 1, further comprising a rotation detector for detecting at least one of a rotation angle and a rotation speed of the rotating wheel relative to the fixed wheel, A target for the rotation detector is installed on an outer periphery of an inboard side portion of the outer ring, which is the rotating ring; A vehicle power plant, wherein a sensing portion of the rotation detector is disposed on an inner periphery of an inboard portion of the stator holding member.

11. 3. The vehicle power unit according to claim 1, wherein the wheel support bearing has an outboard side inner ring arranged on an outer periphery of the outboard side of the inner ring shaft, The vehicle power unit, wherein the inner ring shaft is fitted into the outboard inner ring from the inboard side, and an outboard side shaft end of the inner ring shaft is crimped radially outward.

12. 12. The vehicle power unit according to claim 11, wherein the wheel support bearing further includes an inboard side inner ring disposed on the inboard side of the inner ring shaft, The vehicle power unit, wherein the inner ring shaft is fitted into the outboard and inboard inner rings from the inboard side, and an outboard side shaft end of the inner ring shaft is crimped radially outward.

13. a wheel bearing including a fixed ring and a rotating ring rotatably supported by the fixed ring via rolling elements, the rotating ring being provided with a hub flange to which a wheel of a vehicle is attached; A vehicle power unit including a generator having a stator attached to a fixed ring of the wheel bearing and a rotor attached to a rotating ring of the wheel bearing, The stator is attached to an inboard outer peripheral surface of an inner ring shaft of the wheel bearing which is the fixed ring via a stator holding member, a communication hole for leading wiring of the stator coil to the outside is provided on an inboard end surface of the inner ring shaft, A seal member for preventing intrusion of foreign matter into an internal space is provided on an outer diameter surface of the inboard end of the stator holding member.

Images