Vehicle wheel drive device

Abstract

In this vehicle wheel drive device, a rotary electric machine (12) is accommodated radially inward of a cylindrical vehicle wheel (11) and rotates the vehicle wheel. The rotary electric machine has a rotor (30) and a stator (40) that face each other in the radial direction. The stator has a stator winding (41) and cylindrical holding members (42, 43) that hold the stator winding. A holding member has a flange section (46) that radially extends from an axial end section toward the rotor and faces the rotor in the axial direction, and a terminal part (71) inputs / outputs power to / from the stator winding and is attached to the flange section.

Description

Wheel drive unit CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2022-151562, filed on September 22, 2022, the contents of which are incorporated herein by reference.

[0002] The disclosure herein relates to wheel drives.

[0003] Conventionally, wheel drive devices have been known that have a so-called in-wheel motor structure, in which a rotating electric machine is housed radially inside a wheel. Various technologies have been proposed for in-wheel motors that assume mounting a rotating electric machine on a wheel. For example, Patent Document 1 (JP-A-2005-102626) describes a wiring structure for an in-wheel motor in which a terminal board to which wires extending from each phase winding of a stator winding are connected and a wire holder that holds the wires are provided radially outside the stator in an inner rotor rotating electric machine.

[0004] Japanese Patent Application Laid-Open No. 2004-120910

[0005] However, in the technology described in Patent Document 1, since the terminal board and the wiring holder are provided radially outward from the stator, if the rotating electric machine is placed inside the wheel, there are concerns that the terminal board and the like may interfere with the wheel or that space must be secured inside the wheel for the terminal board and the like. Furthermore, in the case of an outer rotor rotating electric machine, it is conceivable that a brake device or the like may be installed using the space radially inward from the stator (inner stator). In such a case, there is a concern that the terminal board and the like may interfere with the installation of the brake device and the like.

[0006] The present disclosure has been made in consideration of the above circumstances, and has an object to provide a wheel drive device in which a rotating electric machine can be suitably disposed radially inward of a wheel.

[0007] The present disclosure relates to a wheel drive device including a rotating electric machine housed radially inside a cylindrical wheel and rotating the wheel, the rotating electric machine having a rotor and a stator that face each other radially, the stator having a stator winding and a cylindrical holding member that holds the stator winding, the holding member having a flange portion that extends radially toward the rotor at its axial end and faces the rotor in the axial direction, and a terminal portion that inputs and outputs power to and from the stator winding is attached to the flange portion.

[0008] In the rotating electric machine having the above configuration, the axial end of the cylindrical holding member that holds the stator winding extends radially toward the rotor, forming a flange portion that faces the rotor in the axial direction. Terminal portions that input and output power to the stator winding are attached to the flange portion. In this case, since the terminal portions are located near the axial end of the rotor, radial expansion of the rotating electric machine is suppressed. This suppresses interference between components within the wheel and enables effective use of the hollow space in the magnetic circuit consisting of the stator and rotor. As a result, the rotating electric machine can be optimally positioned radially inward of the wheel.

[0009] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which Fig. 1 is a perspective view showing an entire wheel unit, Fig. 2 is a longitudinal sectional view of the wheel unit, Fig. 3 is a front view of a rotating electric machine equipped with a brake device, Fig. 4 is a longitudinal sectional view of the rotating electric machine, Fig. 5 is a perspective view of a stator, Fig. 6 is a perspective view of a stator holder, Fig. 7 is a structural diagram of a rotor carrier, Fig. 8 is a diagram showing the positional relationship between a sensor main body and a refrigerant passage, Fig. 9 is a front view of a rotating electric machine equipped with a brake device in another embodiment, Fig. 10 is a longitudinal sectional view of a rotating electric machine in another embodiment, Fig. 11 is a longitudinal sectional view of a rotating electric machine in another embodiment, Fig. 12 is a longitudinal sectional view of a rotating electric machine in another embodiment, Fig. 13 is a front view of a rotor carrier in another embodiment, and Fig. 14 is a diagram showing the configuration of a refrigerant passage in another embodiment.

[0010] Hereinafter, an embodiment of a wheel drive device according to the present disclosure embodied as a wheel unit will be described with reference to the drawings. The wheel unit is used as a drive wheel of a vehicle such as a four-wheeled vehicle or a two-wheeled vehicle, and includes a wheel on which a tire is mounted and a rotating electric machine (in-wheel motor) housed in a space inside the wheel.

[0011] Fig. 1 is a perspective view showing the entire wheel unit 10, and Fig. 2 is a longitudinal cross-sectional view of the wheel unit 10. Fig. 1 shows the configuration of the wheel unit 10 arranged on the side of the vehicle as seen from the inside of the vehicle. Note that Fig. 1 omits configuration related to the suspension mechanism, such as knuckle arms.

[0012] As shown in FIGS. 1 and 2 , the wheel unit 10 broadly includes a cylindrical wheel 11, a rotating electric machine 12 that rotates the wheel 11, and a brake device 13 that brakes the wheel 11. The rotating electric machine 12 is fixed to the inner periphery of the wheel 11. The rotating electric machine 12 has a fixed portion including a stator 40 and a rotating portion including a rotor 30. The fixed portion is fixed to a vehicle body (not shown), and the rotating portion is fixed to the wheel 11. Rotation of the rotating portion rotates the wheel 11. In the following description, the direction in which the rotation axis of the rotating electric machine 12 (wheel 11) extends is referred to as the axial direction, the direction extending radially from the center of the rotation axis is referred to as the radial direction, and the direction extending circumferentially around the rotation axis is referred to as the circumferential direction. Note that the detailed configuration of the rotating electric machine 12, including the fixed portion and the rotating portion, will be described later. In this embodiment, the rotating electric machine 12 and the brake device 13 correspond to a "wheel drive device."

[0013] The wheel 11 has a tire 21 and a wheel 22 fixed to the inner periphery of the tire 21. The wheel 22 has a hub 23 which is the center of rotation of the wheel 11, a cylindrical rim 24 which surrounds the hub 23, and spokes 25 which connect the hub 23 and the rim 24. The tire 21 is attached to the outer periphery of the rim 24. The hub 23 and the spokes 25 are provided on one axial end of the rim 24, and a rotating electric machine 12 is housed in the inner space of the rim 24 (the inner space of the wheel 22). The rotating electric machine 12 is provided in a fixed state to the hub 23 of the wheel 22.

[0014] The following describes the configuration of the rotating electric machine 12 and the brake device 13. Fig. 3 is a front view of the rotating electric machine 12 equipped with the brake device 13, Fig. 4(a) is a cross-sectional view taken along line 4A-4A in Fig. 3, and Fig. 4(b) is a cross-sectional view taken along line 4B-4B in Fig. 3.

[0015] The rotating electric machine 12 is an outer rotor surface permanent magnet motor, and includes a rotor 30 and a stator 40 disposed radially inside the rotor 30. The rotor 30 and the stator 40 are each cylindrical and disposed opposite each other with an air gap extending in an annular shape therebetween.

[0016] The rotor 30 has a substantially cylindrical rotor carrier 31 and an annular magnet unit 32 fixed to the rotor carrier 31. The rotor carrier 31 is made of a metal material such as iron or aluminum, and has a cylindrical portion 33 and an end plate portion 34 provided on one axial end of the cylindrical portion 33. The rotor carrier 31 is preferably made of a non-magnetic material. The magnet unit 32 is fixed to the inner circumferential surface of the cylindrical portion 33. The rotor carrier 31 functions as a magnet holding member. The other axial end of the rotor carrier 31 is open. The cylindrical portion 33 has an expanded diameter at the tip end on the open side, and an expanded diameter portion 33b is located further forward than the magnet holding portion 33a, which holds the magnet unit 32.

[0017] The magnet unit 32 has a plurality of magnets fixed to the inner circumferential surface of the cylindrical portion 33 of the rotor carrier 31. In the magnet unit 32, the magnets are arranged so that their polarity alternates along the circumferential direction of the rotor 30. As a result, the rotor 30 has a plurality of magnetic poles in the circumferential direction, and each magnetic pole generates magnetic flux. The magnets are, for example, polar-anisotropic permanent magnets, such as sintered neodymium magnets, with an intrinsic coercivity of 400 kA / m or more and a residual magnetic flux density Br of 1.0 T or more. Incidentally, the rotating electric machine 12 may be an interior permanent magnet synchronous machine (IPMSM). The magnet unit 32 corresponds to the "magnetic flux generating unit."

[0018] In the rotor carrier 31, a hub bearing 35 is fixed to the inner surface of the end plate portion 34, which is on the cylindrical portion 33 side, at the radial center of the rotor 30, and a rotating shaft 36 extending in the axial direction is fixed to the hub bearing 35. The hub bearing 35 includes an outer ring 35a, which is a stationary portion, an inner ring 35b, which is a rotating portion, and a plurality of rolling elements 35c (e.g., balls) provided between the outer ring 35a and the inner ring 35b. The inner ring 35b of the hub bearing 35 is fixed to the end plate portion 34. The rotating shaft 36 is fixed to the inner ring 35b so as to be rotatable integrally therewith. The rotating shaft 36 is provided coaxially with the hub 23 at the radial center of the rotating electric machine 12.

[0019] The rotor 30 is assembled to the wheel 11 by fastening the end plate portion 34 of the rotor carrier 31 to the hub 23 of the wheel 22 with fasteners such as bolts.

[0020] Next, the configuration of the stator 40 will be described with reference to Figures 4 to 6. Figure 5 is a perspective view showing the configuration of the stator 40, with Figure 5(a) being a perspective view of the stator 40 seen from one axial side, and Figure 5(b) being a perspective view of the stator 40 seen from the other axial side. Figure 6 is a perspective view of the stator holder 43.

[0021] As shown in Fig. 4, the stator 40 has a stator winding 41, a stator core 42, and a stator holder 43. The stator core 42 and the stator holder 43 are integrated with the stator core 42 on the radially outer side, and the stator winding 41 is assembled to the radially outer side of the stator core 42. The stator core 42 and the stator holder 43 correspond to "holding members."

[0022] The stator winding 41 has a plurality of phase windings, and is formed into a cylindrical shape by arranging the phase windings of each phase in a predetermined order in the circumferential direction. In this embodiment, the stator winding 41 is composed of three phase windings of U, V, and W phases. The stator core 42 is cylindrical and is provided as a back yoke.

[0023] In this embodiment, the stator 40 has a teethless structure that does not have teeth for forming slots. This structure may be any of the following (A) to (C): (A) A structure in which inter-conductor members are provided between each conductor portion (intermediate conductor portion 52 described later) in the circumferential direction in the stator 40, and the inter-conductor members are made of a magnetic material that satisfies the relationship Wt×Bs≦Wm×Br, where Wt is the circumferential width of the inter-conductor member per magnetic pole, Bs is the saturation magnetic flux density of the inter-conductor member, Wm is the circumferential width of the magnet per magnetic pole, and Br is the residual magnetic flux density of the magnet that constitutes the magnet unit 32. (B) A structure in which inter-conductor members are provided between each conductor portion in the circumferential direction in the stator 40, and a non-magnetic material is used as the inter-conductor members. (C) A structure in which no inter-conductor members are provided between each conductor portion in the circumferential direction in the stator 40.

[0024] As shown in Fig. 5, the stator winding 41 has a plurality of partial windings 51, which are unit coils, arranged in a line in the circumferential direction. In the stator winding 41, a phase winding is formed by the plurality of partial windings 51 for each phase. The partial windings 51 are formed by winding a conductor material in multiple layers, and each partial winding has a pair of intermediate conductor portions 52 that are parallel to each other and extend in the axial direction, and a pair of connecting portions 53, 54 that connect the pair of intermediate conductor portions 52 at both axial ends. The pair of intermediate conductor portions 52 and the pair of connecting portions 53, 54 form a ring shape.

[0025] The crossover portions 53, 54 on both axial sides are provided as portions corresponding to the coil ends, and of the crossover portions 53, 54, one crossover portion 53 is bent radially, while the other crossover portion 54 is not bent radially. Each partial winding 51 includes a partial winding 51 in which the crossover portion 53 is bent radially inward, and a partial winding 51 in which the crossover portion 53 is bent radially outward. In the stator 40, at the coil end CE1 on one axial end side, the crossover portion 53 of the partial winding 51 is bent radially inward, and at the coil end CE2 on the other axial end side, the crossover portion 53 of the partial winding 51 is bent radially outward.

[0026] Returning to the explanation of Figure 4, the stator holder 43 has a cylindrical portion 44 assembled to the radially inner side of the stator core 42, an end plate portion 45 provided radially inner of the cylindrical portion 44 at one axial end side of the cylindrical portion 44, and a flange portion 46 provided radially outward from the cylindrical portion 44 at the other axial end side. The stator holder 43 has the end plate portion 45 provided on the same side as the end plate portion 34 of the rotor carrier 31, of both axial sides. The end plate portion 45 corresponds to an inner plate portion extending radially inward in the stator holder 43. As a result, the rotor carrier 31 and the stator holder 43 are configured so that the end plates 34, 45 face each other on one of both axial sides and are open on the other side. In the following description, in order to clearly distinguish between the end plate portions 34 and 45, the end plate portion 34 of the rotor carrier 31 will also be referred to as the "carrier end plate portion 34" and the end plate portion 45 of the stator holder 43 will also be referred to as the "holder end plate portion 45".

[0027] A refrigerant passage 47 through which a refrigerant such as cooling water flows is formed in the cylindrical portion 44. The refrigerant passage 47 extends axially in a flat shape and is provided in an annular shape along the cylindrical portion 44, allowing the refrigerant to flow circumferentially between an inlet and an outlet (not shown). Although not shown, a circulation path for circulating the refrigerant is connected to the inlet and outlet of the refrigerant passage 47. The circulation path is provided with, for example, an electric pump and a heat dissipation device such as a radiator, and the refrigerant circulates through the circulation path and the refrigerant passage 47 of the rotating electric machine 12 as the pump is driven.

[0028] The holder end plate 45 extends radially inward from the cylindrical portion 44 to the hub bearing 35 and serves as a partition plate that axially divides the interior space of the cylindrical portion 44. The holder end plate 45 is formed in two axial stages. The first stage, a base end plate 45a, extends radially inward from the axial end of the cylindrical portion 44, and the second stage, a tip plate 45b, extends radially inward to the hub bearing 35 via an axially extending intermediate cylindrical portion 45c (see FIG. 6). A plurality of holes 45d are formed in the center of the tip plate 45b, and the hub bearing 35 (more specifically, the outer ring 35a of the hub bearing 35) is assembled into the holes 45d. This rotatably supports the rotor carrier 31 (rotor 30) and the rotating shaft 36 relative to the stator holder 43 (stator 40).

[0029] The flange portion 46 is provided axially outside the stator winding 41, i.e., outside the transition portions 53, 54 at one axial end. The flange portion 46 is provided to protrude radially outward beyond the tip of the transition portion 53 (a transition portion formed by bending in the radial direction) of the partial winding 51, and furthermore, is provided to protrude radially outward beyond the magnet holding portion 33a of the cylindrical portion 33 of the rotor carrier 31. In other words, the flange portion 46 has a larger diameter than the outer diameter of the magnet holding portion 33a of the rotor carrier 31, and when the outer diameter of the magnet holding portion 33a of the rotor carrier 31 is D1 and the outer diameter of the flange portion 46 is D2, the relationship D1<D2 is satisfied (see FIG. 4A).

[0030] As shown in FIG. 4 , a wiring module 55 is provided at an axial end of the stator 40 as a winding connecting member electrically connected to each partial winding 51 of the stator winding 41. The wiring module 55 is formed in an annular shape and includes a wiring member such as a bus bar for each phase. The partial windings 51 of each phase are connected in parallel or in series by the wiring module 55, and the phase windings of each phase are also connected to each other by the wiring module 55. The wiring module 55 is provided on the coil end CE2 side, which is the open side of the stator holder 43, of the coil ends CE1 and CE2 on both axial sides of the stator 40. The coil end CE2 is the coil end on the side where the crossover portion 53 of the partial winding 51 is bent radially outward, and the wiring module 55 is provided between each crossover portion 53 and the flange portion 46 of the stator holder 43.

[0031] A power connector 71 serving as a terminal is provided on the flange portion 46 of the stator holder 43, and the wiring module 55 is electrically connected to the power connector 71. The power connector 71 is connected to each of the three-phase power lines in the wiring module 55, allowing connection to an external connector. In this embodiment, the wiring module 55 is provided on the open side of the stator holder 43, i.e., on one of the axial sides closer to the flange portion 46, which simplifies connection of the wiring module 55 to the power connector 71. Note that current sensors that detect phase currents of each phase may be provided integrally with the wiring module 55.

[0032] The power connector 71 is preferably provided at a position that is vertically upper when the rotating electric machine 12 is mounted to the wheel 11. This makes it possible to prevent damage to the power cable connected to the power connector 71 when the rotating electric machine 12 is mounted to the vehicle as an in-wheel motor. For example, if the wheel 11 gets into a ditch or the like while the vehicle is traveling, the power cable connected to the power connector 71 is less likely to be damaged.

[0033] The configuration for installing the power connector 71 will be described below. As shown in FIG. 5B , the flange portion 46 of the stator holder 43 is provided with a base portion 46a serving as a terminal mounting portion for mounting the power connector 71. The base portion 46a is a portion of the flange portion 46 that is locally thicker than other portions. The base portion 46a is provided with a through-hole 46b that penetrates the flange portion 46a in the axial direction, and the power connector 71 is attached by inserting it through the through-hole 46b. This configuration increases the strength of the connector mounting portion. As described above, the flange portion 46 is provided so as to protrude radially outward beyond the tips of the bridge portions 53 of the partial windings 51 and the magnet holding portions 33a of the rotor carrier 31, thereby expanding the axial end surface of the flange portion 46. This ensures an appropriate area for mounting the power connector 71 on the flange portion 46.

[0034] 4, when the rotor 30 is assembled to the stator 40, the flange portion 46 of the stator holder 43 fits into the radially inner side of the expanded diameter portion 33b of the rotor carrier 31, and an annular seal 72 is attached as a sealing member between the radially outer peripheral surface of the flange portion 46 and the expanded diameter portion 33b. This ensures airtightness of the parts that make up the magnetic circuit.

[0035] As shown in Fig. 4, in the stator 40, the inner circumferential side of the cylindrical portion 44 of the stator holder 43 forms a hollow portion 49. This hollow portion 49 is a hollow space inside the magnetic circuit portion consisting of the rotor 30 and the stator 40. In this embodiment, the stator 40 has a teethless structure, which allows the radial thickness of the stator 40 to be thin, and enables the hollow portion 49 to be expanded in the radial direction. The brake device 13 is housed in the hollow portion 49.

[0036] Next, the brake device 13 will be described with reference to FIG.

[0037] The brake device 13 is a disc-type friction braking device and includes a disk-shaped brake disc 61 and a brake caliper 62. Because the brake device 13 may have any configuration for operation, detailed explanation using drawings will be omitted, but the brake disc 61 may be a solid disc made of a single circular plate, a ventilated disc with an internal cavity for ventilation, or the like. The brake caliper 62 is actuated by hydraulic pressure, an electric signal, or the like, and includes a pair of brake pads that come into contact with the brake disc 61 to generate braking force, a piston that presses the brake pads against the brake disc 61, and a caliper body that supports the brake pads and piston.

[0038] The brake disc 61 is fixed by fasteners 63 such as bolts to the tip of the rotating shaft 36, which rotates integrally with the rotor 30. In this case, the brake disc 61 is connected to the rotor carrier 31 via the rotating shaft 36 and the hub bearing 35. Therefore, compared to a configuration in which the brake disc 61 is directly connected to the rotor carrier 31, the effect of braking torque on the rotor 30 can be reduced. In other words, deformation of the rotor carrier 31 due to braking torque is suppressed. Furthermore, compared to a configuration in which the brake disc 61 is directly connected to the rotor carrier 31, heat generated during operation of the brake device 13 is less likely to be transmitted to the rotor 30.

[0039] The brake disc 61 is entirely housed within the hollow portion 49. In terms of its position relative to the wheel 22, it is preferable that the entire brake disc 61 is housed on the inner circumferential side of the rim 24 (see FIG. 2). However, it is also possible to have only a portion of the brake disc 61 housed within the hollow portion 49, or only a portion of the brake disc 61 housed on the inner circumferential side of the rim 24.

[0040] The brake caliper 62 has an arm portion 64 extending laterally from its main body, and the arm portion 64 is fixed to a boss portion 46c provided on the flange portion 46 of the stator holder 43 by a fastener 65 such as a bolt. The shape of the boss portion 46c is also shown in FIG. 5(b). In other words, the main body of the brake caliper 62, excluding the arm portion 64, is housed within the cylindrical portion 44 of the stator holder 43, i.e., within the hollow portion 49. In this case, the arm portion 64 can be fixed to the axial end face of the stator holder 43 from outside the wheel. Furthermore, the brake caliper 62 can be cooled by heat being transferred to the stator holder 43 side via the arm portion 64.

[0041] The brake device 13 is provided in a state where it is housed in a hollow portion 49 of the rotating electric machine 12, i.e., a hollow portion within the magnetic circuit portion of the rotating electric machine 12. In this case, when the brake device 13 is assembled to the rotating electric machine 12, the radial arrangement, as viewed from the central axis side, is the brake caliper 62, the stator 40, the gap, and the rotor 30. In this configuration, the heat dissipation portion (refrigerant passage 47) of the stator holder 43 and the gap are present between the brake caliper 62, which is a heat generating body, and the rotor 30 (magnet), making it difficult for heat from the brake caliper 62 to be transmitted to the rotor 30 (magnet), thereby suppressing demagnetization of the magnet.

[0042] The rotating electric machine 12 also includes a rotation sensor 80 as a rotation detection device that detects the rotation of the rotating shaft 36. The rotation sensor 80 is an inductive proximity sensor, more specifically, an eddy-current inductive sensor. As shown in FIG. 4A , the rotation sensor 80 includes a sensor body 81 as a detection unit and a detected portion 82 whose rotation is to be detected. In this embodiment, the rotation sensor 80 is provided between the holder end plate 45 and the carrier end plate 34. More specifically, the sensor body 81 is provided on the holder end plate 45, while the detected portion 82 is provided on the carrier end plate 34. The brake device 13 is disposed on one side of the holder end plate 45, and the rotation sensor 80 is disposed on the other side.

[0043] The rotation sensor 80 will now be described in detail. As shown in FIG. 5A , the sensor body 81 is attached to the base end plate 45 a of the holder end plate 45. The sensor body 81 has a planar excitation coil and a receiving coil and is elongated and arc-shaped, extending about the rotation axis. The sensor body 81 is attached to the base end plate 45 a of the holder end plate 45 so as to extend in an arc about the rotation axis. More specifically, the axially outer surface of the tip plate 45 b of the holder end plate 45 is formed in a stepped shape, recessed from the radially outer periphery (see FIG. 6 ). The sensor body 81 is fixed to this stepped recess. In this case, the mounting surface to which the sensor body 81 is attached is offset axially from the axial end face of the stator core 42. In other words, the sensor body 81 is positioned so as to overlap the stator core 42 in the axial direction.

[0044] On the other hand, the carrier end plate portion 34 provided with the detection target portion 82 has the following configuration: FIGS.

[0045] 7A, the carrier end plate portion 34 is roughly divided into areas in the radial direction, which are, from the outside in the radial direction, a coil end accommodating area A1, a detection area A2, and a shaft fixing area A3, and these areas A1 to A3 are arranged concentrically in the radial direction. As shown in FIG. 7B, the coil end accommodating area A1 is provided with an annular accommodating portion 34a that protrudes axially toward the side opposite the stator (the back side of the figure) and accommodates the coil end CE1 of the stator winding 41.

[0046] The detection area A2 and the shaft fixing area A3 are recessed axially toward the center of the carrier relative to the coil end housing area A1. The detection area A2 has multiple protrusions 34b spaced at predetermined intervals in the circumferential direction, and the multiple protrusions 34b aligned circumferentially correspond to the detection portion 82. In other words, the detection portion 82, which is made up of multiple protrusions 34b, is integrally molded with the detection area A2 of the carrier end plate 34. Each protrusion 34b has a generally rectangular shape in a front view and protrudes to a certain height. The shaft fixing area A3 also has an insertion hole 34c through which a fastener for fixing the carrier end plate 34 to the hub 23 can be inserted. In this configuration, the detection portion 82 is integrally molded in a portion of the carrier end plate 34 that surrounds the shaft fixing portion. The rotor carrier 31 can be manufactured by casting, forging, cutting, or other methods.

[0047] In this embodiment, a refrigerant passage 48 for cooling the rotation sensor 80 is provided in the base end plate portion 45a of the holder end plate portion 45. This refrigerant passage 48 is a passage that continues to the refrigerant passage 47 provided in the cylindrical portion 44, and when the refrigerant flows through the annular refrigerant passage 47 due to pump operation, the refrigerant flows into the refrigerant passage 48, thereby cooling the sensor main body 81. For ease of explanation, the refrigerant passage 47 provided in the cylindrical portion 44 will also be referred to as the "coil refrigerant passage 47," and the refrigerant passage 48 provided in the holder end plate portion 45 will also be referred to as the "sensor refrigerant passage 48."

[0048] 8A and 8B are diagrams showing the positional relationship between the sensor main body 81 and the refrigerant passage 48, with Fig. 8A being a front view of the stator 40 and Fig. 8B being a cross-sectional view showing the refrigerant passages 47, 48 formed in the stator holder 43. In Figs. 8A and 8B, the up-down direction of the drawings is the vertical direction, and the upper side is the vertically upper side.

[0049] The coil refrigerant passage 47 is annular, and the sensor refrigerant passage 48 extends radially inward from the coil refrigerant passage 47. The coil refrigerant passage 47 has an inlet and an outlet, for example, at the positions shown in the figure, so that refrigerant flowing in through the inlet flows through each of the refrigerant passages 47, 48. The sensor refrigerant passage 48 is preferably arranged so that its upstream portion corresponds to the inlet of the coil refrigerant passage 47 in the circumferential direction. The sensor refrigerant passage 48 is preferably arranged vertically upward, specifically, in an area including the vertically uppermost position of the coil refrigerant passage 47. However, the positions of the inlet and outlet of the coil refrigerant passage 47, the position of the sensor refrigerant passage 48 relative to the inlet and outlet, and the circumferential position of the sensor refrigerant passage 48 can all be changed.

[0050] As can be seen from comparing FIGS. 8( a) and 8(b), the sensor refrigerant passage 48 is provided at a position axially opposite (i.e., overlapping) the sensor main body 81. The circumferential length of the sensor refrigerant passage 48 is preferably equal to or longer than the circumferential length of the sensor main body 81. The radial width of the sensor refrigerant passage 48 is preferably equal to or wider than the radial width of the sensor main body 81. In this case, the axial projected area of ​​the sensor refrigerant passage 48 is preferably equal to or greater than the frontal area of ​​the sensor main body 81 (area when viewed from the front). The sensor refrigerant passage 48 preferably satisfies at least one of the following: the circumferential length is longer than the circumferential length of the sensor main body 81, and the radial width is wider than the radial width of the sensor main body 81.

[0051] The sensor main body 81 may be provided over the entire circumferential direction of the holder end plate portion 45. In such a case, the sensor refrigerant passage 48 may also be provided over the entire circumferential direction.

[0052] Here, the relationship between the brake device 13 and the sensor refrigerant passage 48 will be further explained with reference to FIG.

[0053] On one of the axial sides of the holder end plate 45, the sensor main body 81 is attached to the mounting surface of the base end plate 45a, and the other side faces the brake device 13. In this case, since the brake device 13 is closely opposed to the holder end plate 45 in the hollow portion 49 within the stator holder 43, it is thought that heat generated in the brake device 13 is transferred to the holder end plate 45 by radiation. In particular, it is thought that the greater the area in which the holder end plate 45 and the brake disc 61 face each other in a generally parallel relationship, the more easily the radiant heat is transferred. In this configuration, the sensor refrigerant passage 48 is provided in the holder end plate 45 between the brake device 13 and the sensor main body 81. Therefore, the radiant heat transferred from the brake device 13 is transferred to the refrigerant flowing through the sensor refrigerant passage 48 and moves to the outside of the rotating electric machine 12 along with the movement of the refrigerant. This prevents the radiant heat from the brake device 13 from being transferred to the sensor main body 81 at the holder end plate 45.

[0054] Furthermore, since the holder end plate portion 45 is configured to actively absorb the radiant heat of the brake device 13, radiant cooling of the brake device 13 is promoted, making it possible to suppress a rise in temperature of the brake device 13. Therefore, it is expected that the brake device 13 will be prevented from becoming overheated, resulting in a decrease in braking effectiveness.

[0055] 2, the stator 40 is assembled with the coil end CE1 on the side closer to the hub 23 and the coil end CE2 on the side farther from the hub 23 in the axial direction. In this state, the rotor 30 is disposed radially outside the stator 40, and the brake device 13 is fixed to the radial inside of the stator 40, inserted from the coil end CE2 side. In this case, the brake device 13 can be assembled to the stator 40 from the coil end CE2 side.

[0056] According to the present embodiment described above in detail, the following excellent effects can be obtained.

[0057] The axial end of the stator holder 43 of the rotating electric machine 12 extends radially outward (i.e., toward the rotor 30) to form a flange portion 46 that faces the rotor 30 in the axial direction. A power connector 71 is attached to the flange portion 46. In this case, the installation location of the power connector 71 is secured on the axial end side of the rotor 30, thereby suppressing radial expansion of components in the rotating electric machine 12. This suppresses interference between components within the wheel and enables effective use of the hollow space in the magnetic circuit section consisting of the stator 40 and the rotor 30. As a result, the rotating electric machine 12 can be suitably positioned radially inward of the wheel 11.

[0058] The terminal mounting portion of the flange portion 46 of the stator holder 43, where the power connector 71 (terminal portion) is mounted, is made thicker in parts than the surrounding area. This allows the power connector 71 to be properly mounted to a limited area on the axial end face of the stator 40. Furthermore, because the flange portion 46 is configured to be thicker in parts, it is possible to suppress an increase in weight while increasing strength.

[0059] The flange portion 46 of the stator holder 43 is configured to be radially expanded beyond the magnet holding portion 33a of the rotor carrier 31 to accommodate the power connector 71. This ensures that the area of ​​the flange portion 46 for attaching the power connector 71 is adequately secured.

[0060] The flange portion 46 of the stator holder 43 is arranged to face the rotor 30 and the wiring module 55 in the axial direction. In this case, the space adjacent to the flange portion 46 in the axial direction can be effectively used to suitably arrange the components.

[0061] The brake caliper 62 is fixed to the flange portion 46 of the stator holder 43 at a position circumferentially spaced from the power connector 71. In this case, the flange portion 46 of the stator holder 43 can be used not only as an installation location for the power connector 71 but also as an installation location for the brake caliper 62. In addition to this, it is also possible to provide the flange portion 46 with an inlet port and an outlet port that serve as the inlet and outlet portions of the refrigerant passage 47. It is also possible to provide the flange portion 46 with signal input / output ports for a rotation sensor 80 and a current sensor.

[0062] The coil refrigerant passage 47 is disposed in a position between the brake device 13 and the power connector 71 in the radial direction and is provided so as to overlap with the power connector 71 in the axial direction. This reduces the effect of heat from the brake device 13 on the power connector 71.

[0063] (Other Embodiments) The above embodiment may be modified as follows, for example.

[0064] In the above embodiment, the flange portion 46 of the stator holder 43 is configured so that its entire circumferential length is expanded radially outward beyond the outer diameter of the magnet holding portion 33a of the rotor carrier 31. However, this configuration may be modified. For example, as shown in FIG. 9 , the flange portion 46 of the stator holder 43 may be configured so that a portion of its circumferential length is provided with an expanded portion 46d that expands radially outward (more specifically, the expanded portion 46d is expanded beyond the outer diameter of the magnet holding portion 33a of the rotor carrier 31). In this case, the flange portion 46 has a smaller outer diameter except for the expanded portion 46d, thereby reducing its weight. A power connector 71 is attached to the expanded portion 46d.

[0065] 10 shows a cross-sectional structure of the rotating electric machine 12 having the configuration shown in Fig. 9. In Fig. 10, the expanded diameter portion 33b of the rotor carrier 31 is a plate portion extending in the radial direction, and the flange portion 46 faces the expanded diameter portion 33b in the axial direction. An annular seal 72 is attached between the expanded diameter portion 33b of the rotor carrier 31 and the flange portion 46, which face each other in the axial direction.

[0066] As shown in FIG. 11 , the power connector 71 may be provided on the flange portion 46 of the stator holder 43, oriented diagonally relative to the axial direction. For example, the power connector 71 may be provided on the side of the rotating electric machine 12, facing diagonally upward. In this case, a through-hole 46 b may be provided in the base portion 46 a of the flange portion 46, oriented diagonally relative to the axial direction, and the power connector 71 may be fixed in the through-hole 46 b. This allows the power cable (external cable) to be connected to the power connector 71 from a direction diagonal to the axial direction, facilitating the wiring connection work. Furthermore, considering that a suspension mechanism or the like is provided on the side of the rotating electric machine 12, connecting the power cable diagonally relative to the axial direction makes it easier to avoid interference with the suspension mechanism or the like, and facilitates the wiring layout on the axially outer side of the rotating electric machine 12.

[0067] 12 , the holder end plate 45 is oriented at an acute angle axially inward from the axial end of the cylindrical portion 44, and the sensor body 81 is attached to the holder end plate 45. That is, the end plate 45 has an inclined portion extending obliquely from the axial end of the cylindrical portion 44 in a direction perpendicular to the axial direction, and the sensor body 81 is attached to the inclined portion. Furthermore, the carrier end plate 34 has a detection target 82 integrally molded on an opposing surface parallel to the inclined portion of the holder end plate 45. In this configuration, the inclination of the holder end plate 45 makes it easier to secure a fixing surface for fixing the sensor body 81, and the rotation sensor 80 can be suitably installed even in a rotating electrical machine with a small diameter.

[0068] 13, the convex portions 34b of the detected portion 82 of the rotor carrier 31 may be configured as ribs of a predetermined height extending radially from the rotation center of the rotor 30. Specifically, each convex portion 34b is configured as a ridge portion with its elongated length in the radial direction. This suppresses in-plane deflection of the end plate portion 34 of the rotor carrier 31, thereby maintaining the detection accuracy of the rotation sensor 80.

[0069] 13, the rotor carrier 31 may have a detectable portion 82 integrally molded on one of the two surfaces of the end plate 34 (the surface facing the holder end plate 45), and the other surface (the surface facing away from the holder end plate) may serve as a shaft fixing portion to which the rotating shaft 36 is fixed. In other words, the rotating shaft 36 may be fixed axially outward through a central hole in the end plate 34, and the detectable portion 82 may be integrally molded on the rear surface of the shaft fixing portion. Note that the rotating shaft 36 may extend in any direction from the end plate 34 in a direction perpendicular to the end plate 34.

[0070] The refrigerant passages 47, 48 in the stator holder 43 may be configured as follows. In Fig. 14(a), the axial passage opening area of ​​the sensor refrigerant passage 48 is different between the radially outer and radially inner sides, and the passage opening area is larger on the radially outer side, i.e., on the side of the coil refrigerant passage 47. This promotes the flow of refrigerant from the coil refrigerant passage 47 into the sensor refrigerant passage 48, thereby ensuring optimal cooling of the sensor main body 81.

[0071] In particular, in the configuration shown in FIG. 14( a), a sensor refrigerant passage 48 is provided to extend radially inward of the coil refrigerant passage 47, and in this configuration, the flow of refrigerant from the coil refrigerant passage 47 to the sensor refrigerant passage 48 is favorably promoted.

[0072] 14(b) shows a configuration in which refrigerant flows in series through the coil refrigerant passage 47 and the sensor refrigerant passage 48. In FIG. 14(b), the refrigerant passages 47, 48 extending circumferentially in the stator holder 43 are shown developed in a plan view. In this case, the refrigerant flowing in from the inlet first flows circumferentially through the coil refrigerant passage 47, and then flows out from the outlet through the sensor refrigerant passage 48. This ensures that the refrigerant flows through the sensor refrigerant passage 48, improving the cooling performance of the sensor main body 81. In FIG. 14(b), the refrigerant flows in opposite circumferential directions through the coil refrigerant passage 47 and the sensor refrigerant passage 48, but they can also flow in the same circumferential direction.

[0073] It is also possible to provide the coil refrigerant passage 47 and the sensor refrigerant passage 48 separately, with an inlet and an outlet provided for each of these refrigerant passages 47, 48. In this case, the refrigerant for cooling the stator winding 41 and the refrigerant for cooling the sensor main body 81 are supplied separately, and the manner in which the refrigerant is supplied to each of the refrigerant passages 47, 48 can be adjusted individually.

[0074] In the above embodiment, the power connector 71 is provided as a terminal on the flange 46 of the stator holder 43, but this may be modified. For example, a terminal device having a relay board as a terminal may be attached to the flange 46. The relay board may be provided with a connector to which an external power line can be connected.

[0075] The rotor carrier 31 may be configured such that the cylindrical portion 33 and the disk-shaped end plate portion 34 are formed separately, and the cylindrical portion 33 and the end plate portion 34 are joined together by welding, adhesive, or other joining means. In this case, it is preferable that at least the end plate portion 34 is made of a non-magnetic material. It is also possible to form the convex detection target portion 82 (plurality of convex portions 34b) on the end plate portion 34 by press working.

[0076] - In the rotor carrier 31, the end plate portion 34 and the detected portion 82 of the rotation sensor 80 can be formed separately, and the end plate portion 34 and the detected portion 82 can be fixed to each other with fasteners such as bolts.

[0077] A rotation sensor other than an inductive proximity sensor (inductive sensor) can also be used as the rotation detection device. For example, a resolver can also be used as the rotation detection device.

[0078] The braking device 13 may be configured such that a plurality of brake calipers 62 are provided for one brake disc 61. Alternatively, a plurality of brake discs 61 may be provided on the rotating shaft 36. By configuring the braking device 13 to use a plurality of brake discs 61 or brake calipers 62, the braking force of the in-wheel motor can be increased.

[0079] The rotating electric machine 12 may not be integrally provided with the brake device 13. In this case, the hollow portion 49 on the radially inner side of the stator holder 43 may house electrical components that constitute, for example, an inverter.

[0080] The stator winding 41 is not limited to a configuration using multiple partial windings 51, and may be configured by winding a conductor using wave winding. In this case, the stator winding 41 formed into a cylindrical shape using wave winding may be assembled to a cylindrical stator core 42. The stator 40 may have a structure with teeth. In this case, the stator core is provided with multiple teeth, and the stator winding is wound in slots formed between the teeth.

[0081] The stator 40 may not have the stator core 42. In this case, the stator winding 41 may be assembled to the stator holder 43.

[0082] In the above embodiments, a surface magnet rotor is used as the rotor 30. However, instead of this, a built-in magnet rotor or a field coil rotor may be used.

[0083] In the above embodiments, the rotating electric machine has an outer rotor structure. However, this may be modified to an inner rotor structure. In an inner rotor structure rotating electric machine, the stator is disposed radially outward and the rotor is disposed radially inward. In this case, the flange portion 46 of the stator holder 43 extends radially inward, and the power connector 71 and the like may be provided on the flange portion 46.

[0084] The disclosure in this specification is not limited to the exemplified embodiments. The disclosure encompasses the exemplified embodiments and modifications thereto by those skilled in the art. For example, the disclosure is not limited to the combinations of parts and / or elements shown in the embodiments. The disclosure can be implemented in various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure encompasses the omission of parts and / or elements from the embodiments. The disclosure encompasses the substitution or combination of parts and / or elements between one embodiment and another embodiment. The disclosed technical scope is not limited to the description of the embodiments. Some disclosed technical scopes are defined by the claims, and should be interpreted as including all modifications within the meaning and scope equivalent to the claims.

[0085] The technical concepts extracted from the above-described embodiments are described below. [Configuration 1] A wheel drive device including a rotating electric machine (12) accommodated radially inside a cylindrical wheel (11) and rotating the wheel, the rotating electric machine having a rotor (30) and a stator (40) facing each other in the radial direction, the stator having a stator winding (41) and a cylindrical holding member (42, 43) that holds the stator winding, the holding member having a flange portion (46) that extends radially toward the rotor at an axial end and faces the rotor in the axial direction, and a terminal portion (71) that inputs and outputs power to and from the stator winding is attached to the flange portion. [Configuration 2] The wheel drive device according to Configuration 1, wherein a terminal attachment portion (46a) of the flange portion to which the terminal portion is attached is a thick portion that is partially thicker than its surroundings. [Configuration 3] The wheel drive device according to Configuration 2, wherein a through hole (46b) penetrating in the axial direction is provided in the terminal attachment portion of the flange portion, the terminal portion is fixed to the through hole, and the through hole is provided in an orientation inclined with respect to the axial direction. [Configuration 4] The wheel drive device according to any one of Configurations 1 to 3, wherein the rotating electric machine is an outer rotor rotating electric machine, the rotor includes a cylindrical rotor carrier (31) and a magnetic flux generating portion (32) fixed to the rotor carrier, the flange portion is assembled to an axial end of the rotor carrier, and the flange portion has, in at least a part of the circumferential direction, a portion that is radially expanded beyond a holding portion of the rotor carrier that holds the magnetic flux generating portion, and the terminal portion is provided in the expanded portion. [Configuration 5] The wheel drive device according to any one of Configurations 1 to 4, wherein the stator has a wiring module (55) that is annular and electrically connected to the stator winding, and the wiring module is electrically connected to the terminal portion while being disposed axially between an axial end of the stator winding and the flange portion of the holding member.[Configuration 6] The wheel drive device according to any one of Configurations 1 to 5, wherein the rotating electric machine is an outer rotor type rotating electric machine, and a brake device (13) that generates a frictional braking force on the wheel is arranged in a hollow portion (49) formed radially inside the stator, the brake device having a brake disc (61) and a brake caliper (62), and the brake caliper is fixed to the flange portion at a position circumferentially spaced from the terminal portion. [Configuration 7] The wheel drive device according to any one of Configurations 1 to 6, including a brake device (13) that generates a frictional braking force on the wheel, wherein the brake device is arranged radially inside the holding member, and the holding member is provided with a refrigerant passage (47) that extends circumferentially in a cylindrical portion, and the refrigerant passage is arranged at a position between the brake device and the terminal portion in the radial direction and is arranged so as to overlap the terminal portion in the axial direction.

[0086] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and equivalent modifications. In addition, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

Claims

1. A wheel drive device that is housed inside the wheel (11) in the radial direction and includes a rotary electric machine (12) that rotates the wheel. The rotary electric machine has a rotor (30) and a stator (40) that face each other in the radial direction, The stator has a stator winding (41) and a cylindrical holding member (42, 43) that holds the stator winding, The holding member extends radially toward the rotor side at the axial end and has a flange portion (46) that faces the rotor in the axial direction, The flange portion is provided with a terminal attachment portion (46a) to which a terminal portion (71) for inputting and outputting power to the stator winding is attached. The terminal attachment portion is a thick-walled portion that is partially thicker than its surroundings, A through-hole (46b) that penetrates in the axial direction is provided in the terminal attachment portion of the flange portion, and the terminal portion is fixed to the through-hole. The through-hole is provided in an inclined direction with respect to the axial direction. Wheel drive device.

2. A wheel drive device that is housed inside the wheel (11) in the radial direction and includes a rotary electric machine (12) that rotates the wheel, The rotary electric machine is an outer rotor type rotary electric machine having a rotor (30) and a stator (40) that face each other in the radial direction. A brake device (13) that generates a frictional braking force for the wheel is disposed in a hollow portion (49) formed inside the stator in the radial direction. A wheel drive device, The stator has a stator winding (41) and a cylindrical holding member (42, 43) that holds the stator winding, The holding member extends radially toward the rotor side at the axial end and has a flange portion (46) that faces the rotor in the axial direction, The brake device has a brake disk (61) and a brake caliper (62), A terminal portion (71) for inputting and outputting power to the stator winding is attached to the flange portion, and the brake caliper is fixed at a position circumferentially spaced from the terminal portion. Wheel drive device.

3. A wheel drive device that is housed inside the wheel (11) in the radial direction and includes a rotary electric machine (12) that rotates the wheel and a brake device (13) that generates a frictional braking force for the wheel. The rotary electric machine has a rotor (30) and a stator (40) that face each other in the radial direction. The stator has a stator winding (41) and a cylindrical holding member (42, 43) that holds the stator winding. The holding member extends radially toward the rotor side at an axial end and has a flange portion (46) that axially faces the rotor. A terminal portion (71) for inputting and outputting power to and from the stator winding is attached to the flange portion. The braking device is arranged inside the holding member in the radial direction. The holding member is provided with a refrigerant passage (47) that extends circumferentially in the cylindrical portion. The refrigerant passage is arranged at a position that is between the braking device and the terminal portion in the radial direction and is provided so as to overlap the terminal portion in the axial direction. A wheel drive device.

4. The rotating electrical machine is an outer rotor type rotating electrical machine, and the rotor includes a cylindrical rotor carrier (31) and a magnetic flux generating portion (32) fixed to the rotor carrier. The flange portion is assembled to an axial end of the rotor carrier. The flange portion has a portion that extends radially more than a holding portion that holds the magnetic flux generating portion in the rotor carrier in at least a part of the circumferential direction, and the terminal portion is provided in the extended portion. The wheel drive device according to any one of claims 1 to 3.

5. The stator has a wiring module (55) that is annular and electrically connected to the stator winding. The wiring module is electrically connected to the terminal portion while being arranged between an axial end of the stator winding and the flange portion of the holding member in the axial direction. The wheel drive device according to any one of claims 1 to 3.