Rotary electric machine

Abstract

A rotary electrical machine (12) comprises: a rotor (30) that rotates integrally with a rotating shaft (36); a stator (40) that is disposed oppositely to and radially inward of the rotor; and a rotation detection device (80) that comprises an induction-type proximity sensor which detects rotation of the rotating shaft. The rotor is provided with a cylindrical rotor carrier (31) and a magnetic flux generating part (32) that is fixed to the rotor carrier. The rotor carrier has an end plate part (34) that is opposite from an axial-direction end part of the stator. A detected part (82), which is subject to rotation detection in the rotation detection device, is formed in an integral annular shape surrounding the center of rotation of the rotor on a surface of the end plate part which is opposite from the stator. A detection part (81), which detects rotation of the detected part in the rotation detection device, is provided to the axial-direction end part of the stator.

Description

rotating electrical machines CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2022-151563, filed on September 22, 2022, the contents of which are incorporated herein by reference.

[0002] The disclosure in this specification relates to rotating electrical machines.

[0003] Conventionally, in a rotating electric machine, a rotation detector detects the rotation of a rotating shaft (see, for example, Patent Document 1). A configuration using an induction-type proximity sensor as the rotation detector is also known. Specifically, a configuration is known in which a target, such as a circular disk-shaped target for detecting rotation, is attached to a rotor carrier on the rotor side of the rotating electric machine, and a sensor main body is attached to the stator side.

[0004] Japanese Patent Application Laid-Open No. 2019-75976

[0005] However, with existing technology, the target is assembled to the rotor carrier, and if there are dimensional errors in the components or assembly errors between them, there is a concern that the detection accuracy will decrease.

[0006] The present disclosure has been made in consideration of the above circumstances, and has an object to provide a rotating electric machine that can perform appropriate rotation detection using a rotation detection device made up of an induction type proximity sensor.

[0007] The present disclosure relates to an outer rotor type rotating electric machine comprising: a rotor that rotates integrally with a rotating shaft; a stator that is arranged facing the radially outside of the rotor; and a rotation detection device consisting of an induction type proximity sensor that detects the rotation of the rotating shaft, wherein the rotor comprises a cylindrical rotor carrier and a magnetic flux generating unit fixed to the rotor carrier, and the rotor carrier has an end plate portion facing the axial end of the stator, and on the opposing surface of the end plate portion facing the stator, a detectable portion that is the object of rotation detection in the rotation detection device is integrally molded in a circular ring shape surrounding the center of rotation of the rotor, while a detection portion that detects the rotation of the detectable portion in the rotation detection device is provided at the axial end of the stator.

[0008] In the rotating electric machine having the above configuration, the rotation detection device including an inductive proximity sensor includes a detection target, whose rotation is to be detected, and a detection unit that detects the rotation of the detection target, and these are arranged in close proximity to each other. In this case, the closer the distance between the detection target and the detection unit, the more likely it is that the detection accuracy will improve, but the greater the risk of contact between them. In this regard, according to the above configuration, the detection target and the detection unit are integrally molded on the surface of the end plate of the rotor carrier that faces the stator, thereby maintaining an appropriate distance between them. In other words, unlike conventional configurations in which the end plate of the rotor carrier and the detection target are formed separately and then assembled together, assembly errors and the like are eliminated, allowing the detection target and the detection unit to be arranged appropriately close to each other. As a result, the rotation detection device including the inductive proximity sensor can perform appropriate rotation detection.

[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 rotation sensor 80, which is an inductive proximity sensor, includes a detection target 82, whose rotation is to be detected, and a sensor body 81, which detects the rotation of the detection target 82. These components are positioned close to each other and face each other. In this case, the closer the distance between the detection target 82 and the sensor body 81, the more likely it is that the detection accuracy will improve, but the greater the risk of contact between them. In this regard, the above-described configuration, in which the detection target 82 is integrally molded on the surface of the end plate 34 of the rotor carrier 31 that faces the stator 40, allows the detection target 82 and the sensor body 81 to be maintained at an appropriate distance. In other words, unlike conventional configurations in which the end plate 34 of the rotor carrier 31 and the detection target 82 are formed separately and then assembled together, assembly errors are eliminated, allowing the detection target 82 and the sensor body 81 to be positioned appropriately close to each other. As a result, the rotation sensor 80, which is an inductive proximity sensor, can perform appropriate rotation detection.

[0058] If the carrier end plate 34 and the detected portion 82 are formed separately, a configuration is conceivable in which a ring-shaped plate material with continuous concave and convex portions in the circumferential direction is assembled to the carrier end plate 34. Comparing the case in which the detected portion 82 is assembled to the carrier end plate 34 with the case in which a plurality of convex portions 34b are integrally formed on the carrier end plate 34 as the detected portion 82, the latter allows the thickness dimension of the carrier end plate 34 at the portion corresponding to the detected portion 82 to be smaller, and ultimately allows the axial length of the rotating electric machine 12 to be reduced.

[0059] The carrier end plate 34 has a double structure in the radial direction, with a shaft fixing portion (shaft fixing area A3) and a detection portion 82 (detection area A2). In this case, the shaft fixing portion of the rotor carrier 31 is a portion of the rotor 30 where rotational fluctuation is unlikely to occur, and the detection portion 82 is integrally molded so as to surround the shaft fixing portion, thereby enabling stable, high-precision detection by the rotation sensor 80.

[0060] The sensor body 81 and the detected portion 82 of the rotation sensor 80 are configured to be disposed radially inside the coil end portion of the stator winding 41. In this case, the rotation sensor 80 can be disposed while effectively utilizing the hollow portion radially inside the coil end portion of the rotating electric machine 12. Furthermore, by overlapping the coil end portion and the rotation sensor 80 in the axial direction, the axial length of the rotating electric machine 12 can be shortened.

[0061] The holder end plate 45 and the carrier end plate 34 are arranged to face each other in the axial direction, and the sensor body 81 and the detected portion 82 of the rotation sensor 80 are provided at the opposing portions. In this case, the rotation sensor 80 can be disposed by making good use of the space inside the stator 40 in the radial direction.

[0062] Since the holder end plate portion 45 (inner plate portion) is provided so as to extend radially inward from the axial end portion of the cylindrical portion 44, the hollow space radially inside the stator holder 43 can be expanded compared to when the holder end plate portion 45 is provided so as to extend from the axial middle portion of the cylindrical portion 44. Therefore, the hollow space can be suitably used as an installation space for the brake device 13.

[0063] The sensor body 81 of the rotation sensor 80 is provided at a position on the holder end plate 45 that overlaps the stator core 42 in the axial direction. In this case, the axial length of the magnetic circuit section consisting of the stator and rotor can be secured to increase output, while the axial dimension of the installation portion of the rotation sensor 80 can be reduced.

[0064] The holder end plate 45 is provided with a sensor coolant passage 48 for cooling the rotation sensor 80. This reduces the effect of heat generated by the brake device 13 on the rotation sensor 80, thereby optimizing rotation detection by the rotation sensor 80.

[0065] (Other Embodiments) The above embodiment may be modified as follows, for example.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] In particular, in the configuration shown in FIG. 14( a), the sensor refrigerant passage 48 is provided so as 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] The technical concepts extracted from the above-described embodiments are described below. [Configuration 1] An outer-rotor rotating electric machine (12) including a rotor (30) that rotates integrally with a rotating shaft (36), a stator (40) that is disposed facing the rotor on the radially outer side, and a rotation detection device (80) consisting of an induction-type proximity sensor that detects rotation of the rotating shaft, wherein the rotor includes a cylindrical rotor carrier (31) and a magnetic flux generating portion (32) fixed to the rotor carrier, the rotor carrier having an end plate portion (34) that faces an axial end of the stator, a detection target portion (82) that is the object of rotation detection in the rotation detection device is integrally formed in an annular shape around the center of rotation of the rotor on a surface of the end plate portion that faces the stator, and a detection portion (81) that detects rotation of the detection target portion in the rotation detection device is provided at an axial end of the stator. [Configuration 2] The rotating electric machine of Configuration 1, wherein the opposing surface of the end plate is provided with a plurality of protrusions (34b) arranged at predetermined intervals in the circumferential direction as the detected portion. [Configuration 3] The rotating electric machine of Configuration 2, wherein the plurality of protrusions as the detected portion are ribs of a predetermined height extending radially from the rotation center side of the rotor. [Configuration 4] The rotating electric machine of any one of Configurations 1 to 3, wherein the rotating shaft is fixed to a radial center of the end plate, and the detected portion is integrally molded in a portion of the end plate that surrounds a shaft fixing portion to which the rotating shaft is fixed or in a portion on the back side of the shaft fixing portion. [Configuration 5] The rotating electric machine according to any one of configurations 1 to 4, wherein the stator has a stator winding (41) and a stator core (42) assembled radially inward of the stator winding, the stator winding has a coil end portion that protrudes axially outward beyond an axial end face of the stator core, and the detected portion and the detecting portion of the rotation detection device are provided radially inward of the coil end portion.[Configuration 6] The rotating electric machine according to any one of Configurations 1 to 4, wherein the stator has a stator winding (41) and a cylindrical holding member (42, 43) that holds the stator winding while being assembled radially inside the stator winding, the holding member having an inner plate portion (45) extending radially inward, a bearing (35) that rotatably supports the rotor fixed to a radially leading end side of the inner plate portion, the inner plate portion axially facing the end plate portion of the rotor carrier, and the detection unit is fixed to an opposing surface of the inner plate portion that faces the end plate portion. [Configuration 7] The rotating electric machine according to Configuration 6, wherein the holding member has a stator core (42) assembled radially inside the stator winding, and a stator holder (43) having a cylindrical portion (44) assembled radially inside the stator core, the inner plate portion being arranged to extend radially inward from an axial end of the cylindrical portion. [Configuration 8] The rotating electric machine of Configuration 7, wherein the detection portion is provided at a position on the inner plate portion that overlaps with the stator core in the axial direction. [Configuration 9] The rotating electric machine of Configuration 7, wherein the inner plate portion has an inclined portion extending obliquely from an axial end of the cylindrical portion in a direction perpendicular to the axial direction, and the detection portion is provided on the inclined portion, while the detected portion is integrally molded on an opposing surface of the end plate portion of the rotor carrier that is parallel to the inclined portion. [Configuration 10] The rotating electric machine of any one of Configurations 1 to 9, wherein the stator has a stator winding (41) and a cylindrical holding member (42, 43) that holds the stator winding in a state where it is assembled radially inward of the stator winding, and the holding member has an inner plate portion (45) extending radially inward, the rotation detection device is attached to a plate surface of the inner plate portion, and a refrigerant passage (48) for circulating a refrigerant is provided in the inner plate portion.

[0088] 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. An outer rotor type rotating electric machine (12) including a rotor (30) that rotates integrally with a rotating shaft (36), a stator (40) that is disposed radially inwardly opposite the rotor, and a rotation detection device (80) that is an inductive proximity sensor that detects rotation of the rotating shaft, The rotor includes a cylindrical rotor carrier (31) and a magnetic flux generating unit (32) fixed to the rotor carrier, The rotor carrier has an end plate portion (34) facing an axial end of the stator, The stator includes a stator winding (41), a stator core (42) assembled to the stator winding, and a stator holder (43) having a cylindrical portion (44) assembled to the radially inner side of the stator core, The stator holder has an inner plate portion (45) extending radially inward from the cylindrical portion and axially facing the end plate portion of the rotor carrier, a detection target (82) which is an object of rotation detection in the rotation detection device is integrally formed in an annular shape around the center of rotation of the rotor on a facing surface of the end plate portion of the rotor carrier which faces the inner plate portion of the stator holder, while a detection portion (81) which detects rotation of the detection target is provided on a facing surface of the inner plate portion of the stator holder which faces the end plate portion, A rotating electric machine in which the cylindrical portion of the stator holder has an inner plate portion on one axial end side and is open on the other axial end side, and a brake device (13) for braking the rotation of the rotor is provided in the hollow portion radially inside the cylindrical portion, on the opposite side of the detection portion, across the inner plate portion.

2. The rotating electric machine according to claim 1 , wherein the detection portion is provided at a position on the inner plate portion so as to overlap with the stator core in the axial direction.

3. The inner plate portion has an inclined portion extending obliquely from an axial end portion of the cylindrical portion in a direction perpendicular to the axial direction, and the detection portion is provided on the inclined portion. 2 . The rotating electric machine according to claim 1 , wherein the detection target portion is integrally formed on an opposing surface of the end plate portion of the rotor carrier that is parallel to the inclined portion.

4. A rotating electric motor as described in any one of claims 1 to 3, wherein a refrigerant passage (48) for circulating a refrigerant is provided in the inner plate portion.

5. The rotating electric machine according to claim 1 , wherein the opposed surface of the end plate is provided with a plurality of protrusions arranged at predetermined intervals in a circumferential direction as the detection target portion.

6. 6. The rotating electric machine according to claim 5, wherein the plurality of protrusions as the detected portions are ribs having a predetermined height and extending radially from a rotation center side of the rotor.

7. The rotating shaft is fixed to a radial center portion of the end plate portion, 2 . The rotating electric machine according to claim 1 , wherein the detection target portion is integrally formed with the end plate at a portion surrounding a shaft fixing portion to which the rotating shaft is fixed, or at a portion on a rear side of the shaft fixing portion.

8. 2. The rotating electric machine according to claim 1, wherein the stator winding has a coil end portion that protrudes axially outward beyond the axial end face of the stator core, and the detected portion and the detection portion of the rotation detection device are provided radially inside the coil end portion.