In-wheel motor

Abstract

An in-wheel motor (30, 300) comprises: a bracket unit (70, 370); a stator (50, 350) connected to the bracket unit; a rotor (40, 340) which includes a shaft (31, 331) and field poles, and which is connected to a wheel (10); a bearing (60, 360) rotatably supporting the shaft; and a rotation angle sensor (80, 380). The shaft extends to a position facing an inner circumferential surface of the bracket unit in a radial direction of the shaft. The rotation angle sensor includes: a rotor-side sensor unit (81, 381) attached to a position on the shaft facing the inner circumferential surface of the bracket unit in the radial direction; and a bracket-side sensor unit (82, 382) which outputs a signal corresponding to a rotation angle of the rotor-side sensor unit. The in-wheel motor is provided with a sealing cover (110, 410) closing a gap between the rotor-side sensor unit and the bracket-side sensor unit.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2022-133177, filed on August 24, 2022, the contents of which are incorporated herein by reference. [Technical Field]

[0002] The present disclosure relates to an in-wheel motor that is at least partially housed in an inner space of a wheel having a rim portion to which a tire can be attached and a disc portion provided on a side surface of the rim portion. [Background technology]

[0003] A known example of this type of in-wheel motor is one in which a hub bearing that rotatably supports a rotor shaft is attached to a bracket fixed to the vehicle body, as described in Patent Document 1. A resolver is disposed radially outward of the hub bearing as a rotation angle sensor that detects the rotation angle of the rotor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6194750 Summary of the Invention

[0005] In the in-wheel motor described in Patent Document 1, an oil seal is provided between the outer yoke of the rotor and the bracket to prevent water and dust from entering the motor. External forces may act on the bracket due to vibrations or impacts from the road surface, causing the bracket to deform. In this case, a gap may form between the bracket and the oil seal, allowing water and dust to enter the motor through the gap and potentially adhere to the rotation angle sensor.

[0006] A primary object of the present disclosure is to provide an in-wheel motor that can prevent water and dust from adhering to a rotation angle sensor.

[0007] The present disclosure is applicable to a mobile body equipped with a wheel having a rim portion to which a tire can be attached and a disc portion provided on a side surface of the rim portion, and an in-wheel motor that is at least partially housed in a wheel inner space surrounded by the disc portion and the rim portion and rotates the wheel, a tubular bracket portion extending in a vehicle width direction of the moving body; a stator connected to the bracket portion; a rotor having a shaft extending in the vehicle width direction and a field pole, the rotor being connected to the wheel; a bearing that is provided axially of the shaft and is located outward in the vehicle width direction from the bracket portion and that rotatably supports the shaft; A rotation angle sensor; Equipped with the shaft extends inward in the axial direction in the vehicle width direction to a position facing an inner circumferential surface of the bracket portion in the radial direction of the shaft, The rotation angle sensor a rotor-side sensor portion attached to the shaft at a position facing an inner circumferential surface of the bracket portion in the radial direction; a bracket-side sensor portion attached to an inner circumferential surface of the bracket portion at a position facing the rotor-side sensor portion in the radial direction of the shaft, the bracket-side sensor portion outputting a signal corresponding to the rotation angle of the rotor-side sensor portion; and the bracket portion is fixed to the cover portion in a state where an opening on an inner side in the vehicle width direction of the bracket portion is closed by a cover portion fixed to a chassis portion of the moving body or a cover portion constituting the chassis portion, A seal cover is provided on the inner periphery of the bracket portion, and seals the gap between an opening of the bracket portion on the inner side in the vehicle width direction and the rotor-side sensor portion and the bracket-side sensor portion.

[0008] The bracket portion of the present disclosure extends in the vehicle width direction and is tubular. Therefore, a shaft can be inserted from an opening on the outer side of the bracket portion in the vehicle width direction into the inner space of the bracket portion. Specifically, the shaft extends axially inward in the vehicle width direction to a position facing the inner circumferential surface of the bracket portion in the radial direction.

[0009] In addition, in the present disclosure, a rotor-side sensor portion extending radially outward is attached to the shaft at a position shifted inward in the vehicle width direction from the bearing and facing the inner circumferential surface of the bracket portion in the radial direction. A bracket-side sensor portion is attached to the bracket portion at a position facing the rotor-side sensor portion in the radial direction.

[0010] The bracket is fixed to the cover with the opening on the inner side of the bracket in the vehicle width direction being blocked by the cover fixed to the chassis or the cover constituting the chassis. An external force acting on the cover can create a gap between the bracket and the cover. In this case, water or dust can get in through the gap, potentially adhering to the rotor-side sensor or the bracket-side sensor.

[0011] Therefore, the present disclosure provides a seal cover that is provided on the inner periphery of the bracket portion and that seals the gap between the rotor-side sensor portion and the bracket-side sensor portion and the opening on the inner side of the bracket portion in the vehicle width direction. Therefore, even if a gap occurs between the bracket portion and the cover portion and water or dust enters through the gap, the seal cover can prevent the water or dust from adhering to the rotor-side sensor portion and the bracket-side sensor portion. [Brief explanation of the drawings]

[0012] 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: [Figure 1] FIG. 1 is a cross-sectional view of a wheel unit according to a first embodiment; [Figure 2] FIG. 2 is an enlarged view of the hub bearing and bracket portion of the configuration of FIG. 1; [Figure 3] FIG. 3 is a view of the bracket portion with the resolver, cover, seal cover, etc. removed, as seen from the inside in the vehicle width direction. [Figure 4] FIG. 4 is a view of the bracket portion with the cover removed, seen from the inside in the vehicle width direction. [Figure 5] FIG. 5 is an enlarged view of a bracket portion and its surrounding area according to a second embodiment; [Figure 6] FIG. 6 is an enlarged view of a bracket portion and its surrounding area according to a third embodiment; [Figure 7] FIG. 7 is a cross-sectional view of a wheel unit according to a fourth embodiment; [Figure 8] FIG. 8 is an enlarged view of the bracket portion and its surrounding area in the configuration of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] Several embodiments will be described with reference to the drawings. In several embodiments, functionally and / or structurally corresponding and / or associated parts may be assigned the same reference numerals or reference numerals that differ in the hundredth or more digit. For corresponding and / or associated parts, reference may be made to the descriptions of other embodiments.

[0014] First Embodiment A first embodiment of an in-wheel motor according to the present disclosure will be described below with reference to Figs. 1 and 2. The in-wheel motor, together with a wheel on which a tire is mounted, constitutes a wheel unit that serves as a driving wheel. The wheel unit of this embodiment is applied to vehicles such as electric vehicles or hybrid vehicles.

[0015] The wheel unit includes a wheel 10. The wheel 10 includes a cylindrical rim portion 11 and a disk-shaped disc portion 12 provided at the outer end of the rim portion 11 in the vehicle width direction. A tire 13 is attached to the outer periphery of the wheel 10.

[0016] The wheel unit includes an in-wheel motor 30 that rotates the wheel 10. The in-wheel motor 30 is attached to a chassis portion of the vehicle. More specifically, the in-wheel motor 30 is attached to a knuckle 20 of a suspension device that constitutes the chassis portion. The knuckle 20 includes a mounting portion 21 that extends in the vertical direction, a lower arm 22 that extends inward in the vehicle width direction from the lower end of the mounting portion 21, and an upper arm 23 that extends inward in the vehicle width direction from the upper end of the mounting portion 21. The in-wheel motor 30 is attached to the mounting portion 21. Note that, although this embodiment shows an example in which the wheel unit is not a steered wheel, the wheel unit may also be a steered wheel.

[0017] At least a portion of the in-wheel motor 30 is housed in the inner space of the wheel 10, which is the space radially inward from the rim portion 11, and applies rotational power to the wheel 10. The in-wheel motor 30 is an outer rotor type motor including a shaft 31 extending in the vehicle width direction, a rotor 40, and a stator 50 arranged radially inward of the rotor 40.

[0018] The rotor 40 includes a cylindrical magnet holder 41 and a magnet unit 42 provided on the inner peripheral surface of the magnet holder 41. The magnet holder 41 faces the inner peripheral surface of the rim portion 11 from its outer end to its inner end in the vehicle width direction. The magnet unit 42 is cylindrical and concentric with the central axis of rotation of the rotor 40, and includes multiple magnets fixed to the inner peripheral surface of the magnet holder 41. In other words, the in-wheel motor 30 of this embodiment is a surface permanent magnet synchronous machine (SPMSM). The magnets in the magnet unit 42 are arranged with alternating polarities along the circumferential direction of the rotor 40. This results in multiple magnetic poles being formed in the magnet unit 42 along the circumferential direction. 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. The in-wheel motor 30 may also be an interior permanent magnet synchronous machine (IPMSM).

[0019] The inner end of the magnet holding portion 41 in the vehicle width direction is a bent portion that is bent radially inward of the rotor 40. The rotor 40 has a disk-shaped flat plate portion 43 that serves as a connecting portion that connects the outer end of the magnet holding portion 41 in the vehicle width direction to the shaft 31. The disk portion 12 is fixed to the flat plate portion 43 with bolts and nuts. This allows the rotor 40 and the wheel 10 to rotate integrally. The magnet holding portion 41 and the flat plate portion 43 may be made of a non-magnetic material (e.g., aluminum or synthetic resin) or a magnetic material (e.g., iron).

[0020] The stator 50 includes a cylindrical stator winding 51 disposed radially opposite the magnet unit 42, a cylindrical stator core 52 provided radially inside the stator winding 51, and a base portion 53 provided radially inside the stator core 52. The stator core 52 is made of a magnetic material (more specifically, a soft magnetic material), for example, an electromagnetic steel plate.

[0021] The stator winding 51 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 51 is composed of three-phase windings of U, V, and W phases. Each phase winding is formed by multiple turns of conductor material, and has a pair of intermediate conductor parts that are parallel to each other and extend in the axial direction of the shaft 31 (vehicle width direction), and a pair of crossover parts that connect the pair of intermediate conductor parts at both axial ends, and is formed into an annular shape by the pair of intermediate conductor parts and the pair of crossover parts.

[0022] In this embodiment, the stator core 52 has a slotless structure that does not have teeth for forming slots. This structure may be any of the following structures (A) to (C).

[0023] (A) In the stator 50, inter-wire members are provided between each intermediate conductor portion in the circumferential direction, and the inter-wire members are made of a magnetic material that satisfies the relationship Wt×Bs≦Wm×Br, where Wt is the circumferential width of the inter-wire member at one magnetic pole, Bs is the saturation magnetic flux density of the inter-wire member, Wm is the circumferential width of the magnet at one magnetic pole, and Br is the residual magnetic flux density of the magnet that constitutes the magnet unit 42.

[0024] (B) In the stator 50, a wire-to-wire member is provided between each intermediate wire portion in the circumferential direction, and a non-magnetic material is used as the wire-to-wire member.

[0025] (C) A structure in which no inter-conductor members are provided between the respective intermediate conductor portions in the circumferential direction in the stator 50.

[0026] The base portion 53 is a component for connecting the configuration of the stator 50 side of the in-wheel motor 30 with the mounting portion 21 of the knuckle 20. The base portion 53 is also a component for rotatably supporting the shaft 31.

[0027] The base portion 53 functions as a housing for the stator 50 and includes a cylindrical core mounting portion 54 extending in the vehicle width direction, and an annular portion 55 extending radially inward from the outer end of the core mounting portion 54 in the vehicle width direction. A through hole 56 through which the shaft 31 is inserted is formed in the center of the annular portion 55. The stator core 52 is attached to the outer end of the core mounting portion 54 in the radial direction. A hollow portion is formed radially inward of the core mounting portion 54. A bracket portion 70 is disposed in this hollow portion.

[0028] The bracket portion 70 includes a cylindrical main body portion 71 extending in the axial direction of the shaft 31, and an annular bracket-side flange portion 72 extending radially outward from the outer end portion of the main body portion 71 in the vehicle width direction. The bracket portion 70 is made of a non-magnetic material, and more specifically, is made of a non-magnetic metallic material (e.g., aluminum). The bracket portion 70 in this embodiment is configured as a separate member from the base portion 53. A plurality of bolt insertion holes 72a, which penetrate in the axial direction and through which bolts 92 are inserted, are formed in the bracket-side flange portion 72 at predetermined intervals in the circumferential direction.

[0029] The in-wheel motor 30 includes a hub bearing 60 that rotatably supports the shaft 31 relative to an annular portion 55 that constitutes the base portion 53. The hub bearing 60 is a rolling bearing that includes a cylindrical outer ring 61, an inner ring 62, and a plurality of rolling elements 63 (e.g., balls) arranged between the outer ring 61 and the inner ring 62.

[0030] The outer ring 61 includes an outer ring cylinder portion 61a extending in the axial direction of the shaft 31, and an annular outer ring flange portion 61b extending radially outward from an axially intermediate portion of the outer ring cylinder portion 61a.

[0031] The radially inner end of the annular portion 55 is an annular bearing mounting portion 55a that is recessed from the outer side in the vehicle width direction toward the inner side in the vehicle width direction. Bolt insertion holes 55b, 61c that penetrate in the axial direction for inserting bolts 92 are formed in the bearing mounting portion 55a and the outer ring side flange portion 61b at predetermined intervals in the circumferential direction and in the same number as the bolt insertion holes 72a. The bolt insertion holes 61c in the outer ring side flange portion 61b are female-threaded holes with female threads formed therein.

[0032] The bracket-side flange portion 72 abuts against the inner end face of the bearing mounting portion 55a in the vehicle width direction, and the outer-ring-side flange portion 61b abuts against the outer end face of the bearing mounting portion 55a in the vehicle width direction. In this state, bolts 92 are inserted into the bolt insertion holes 72a, 55b, 61c with their heads facing inward in the vehicle width direction, and the male threads of the bolts 92 are screwed into the female threaded holes, which are the bolt insertion holes 61c. In this way, the bracket portion 70 and the hub bearing 60 are fixed to the annular portion 55.

[0033] The inner ring 62 of the hub bearing 60 has an inner ring tubular portion 62a that is cylindrical and has a smaller diameter than the outer ring 61, and an inner ring-side flange portion 62b that extends from one axial end of the inner ring tubular portion 62a in a direction intersecting (perpendicular to) the axial direction. The shaft 31 is fixed to the inner ring tubular portion 62a. The inner ring-side flange portion 62b has a plurality of protrusions 62c formed at predetermined intervals around the circumferential direction and extending outward in the vehicle width direction. Male threads are formed at the tips of the protrusions 62c. A through hole 43a is formed in the flat plate portion 43 of the rotor 40. With the inner ring-side flange portion 62b abutting against the inner end face of the flat plate portion 43 in the vehicle width direction and the protrusions 62c inserted into the through hole 43a, a nut 90 is screwed onto the male threads at the tips of the protrusions 62c. This fixes the flat plate portion 43 to the inner ring 62. Therefore, the inner ring 62, the rotor 40 and the wheel 10 rotate together.

[0034] An annular restricting portion 34 extending radially outward is formed in the axially intermediate portion of the shaft 31. A male thread is formed in a tip end portion 35 on the outer side in the vehicle width direction of the shaft 31. A nut 91 is screwed onto the male thread on the tip end portion 35 with the restricting portion 34 abutting the axial end face of the inner ring cylindrical portion 62a. This fixes the shaft 31 to the inner ring 62.

[0035] Of the main body 71 of the bracket part 70, a portion of the main body 71 that is a first predetermined length in the axial direction from the opening on the outer side in the vehicle width direction is a thick-walled portion 75. Of the main body 71, a portion of the main body 71 that is a second predetermined length in the axial direction from the opening on the inner side in the vehicle width direction is a thin-walled portion 73 (corresponding to the "seal placement portion"). Of the main body 71, a portion between the thick-walled portion 75 and the thin-walled portion 73 is a medium-walled portion 74 (corresponding to the "sensor placement portion"). The inner diameter dimension of the medium-walled portion 74 is larger than the inner diameter dimension of the thick-walled portion 75, and the inner diameter dimension of the thin-walled portion 73 is larger than the inner diameter dimension of the medium-walled portion 74. The outer diameter dimensions of the thick-walled portion 75, the medium-walled portion 74, and the thin-walled portion 73 are the same.

[0036] The boundary between the thin portion 73 and the medium-thickness portion 74 is a first step portion 76, and the boundary between the medium-thickness portion 74 and the thick portion 75 is a second step portion 77. The first step portion 76 and the second step portion 77 are annular in shape, as shown in FIG.

[0037] The in-wheel motor 30 includes a resolver 80 as a rotation angle sensor that detects the rotation angle (electrical angle) of the rotor 40. The resolver 80 includes a resolver rotor 81 (corresponding to a "rotor-side sensor unit") attached to the inner end of the shaft 31 in the vehicle width direction, and a resolver stator 82 (corresponding to a "bracket-side sensor unit") arranged radially outwardly of the resolver rotor 81 so as to face the resolver rotor 81. The resolver rotor 81 is disk-shaped and is inserted through the shaft 31 and is provided coaxially with the shaft 31. The resolver stator 82 includes a circular back yoke and a coil 83 wound around a plurality of teeth extending radially inward from the back yoke. The coil 83 includes an excitation coil and a pair of output coils.

[0038] The excitation coil is excited by a sine wave excitation signal, and the magnetic flux generated in the excitation coil by the excitation signal interlinks the pair of output coils. At this time, the relative positional relationship between the excitation coil and the pair of output coils periodically changes according to the rotation angle of the resolver rotor 81, so the number of magnetic fluxes interlinking the pair of output coils periodically changes. As a result, a signal according to the rotation angle is output from the output coil.

[0039] A through-hole 57 is formed in the annular portion 55 of the base portion 53, penetrating in the axial direction. A power line 58 is inserted through the through-hole 57, electrically connecting the stator winding 51 to the inverter and carrying three-phase AC current. A power storage unit is electrically connected to the inverter. The power storage unit is, for example, a storage battery such as a lithium-ion storage battery. The switching control of the upper and lower arm switches that make up the inverter is performed by a control device. This causes the rotor 40 to rotate, and the wheel unit to rotate. In this embodiment, the inverter, the power storage unit, and the control device are provided in a portion of the vehicle other than the wheel unit (for example, a chassis portion or a body portion).

[0040] Next, the mounting positions of the resolver rotor 81 and the resolver stator 82 will be described.

[0041] First, the mounting position of the resolver rotor 81 will be described. The inner end of the shaft 31 in the vehicle width direction is the small diameter portion 36. Furthermore, the portion of the shaft 31 adjacent to the small diameter portion 36 in the axial direction is the large diameter portion 37, which has a radial dimension larger than that of the small diameter portion 36. Between the small diameter portion 36 and the large diameter portion 37 is a stepped portion 38 with which the axial end face of the resolver rotor 81 abuts. The stepped portion 38 faces the inner circumferential surface of the thin-walled portion 73 in the radial direction. The portion of the shaft 31 adjacent to the large diameter portion 37 in the axial direction is the restricting portion 34. A male thread is formed at the tip end 39 of the small diameter portion 36.

[0042] The small diameter portion 36 faces the inner circumferential surface of the medium thickness portion 74 of the bracket portion 70 in the radial direction. With the resolver rotor 81 inserted into the small diameter portion 36 and the end of the resolver rotor 81 abutting against the stepped portion 38, a nut 93 is screwed onto the male threads on the tip portion 39 of the small diameter portion 36. As a result, the resolver rotor 81 is sandwiched between the stepped portion 38 and the nut 93, and the resolver rotor 81 is attached to the shaft 31.

[0043] The configuration in which the step portion 38 is provided on the shaft 31 makes it easy to position the resolver rotor 81 in the axial direction. Also, it is possible to improve the concentricity of the resolver rotor 81 with respect to the central axis of rotation of the shaft 31. This improves the accuracy of calculating the electrical angle.

[0044] The shaft 31 extends inward in the vehicle width direction relative to the hub bearing 60. Therefore, the resolver rotor 81 can be attached to the inner end portion in the vehicle width direction of the shaft 31. As a result, the outer diameter dimension of the resolver rotor 81 can be made smaller than the outer diameter dimension of the outer ring cylinder portion 61a, and in this embodiment, can be made smaller than the outer diameter dimension of the inner ring cylinder portion 62a.

[0045] Next, a description will be given of the mounting position of the resolver stator 82. The resolver stator 82 is mounted to the bracket portion 70 with the end of the resolver stator 82 abutting against the second step portion 77 of the bracket portion 70.

[0046] A through hole 74a is formed in a portion of the intermediate portion 74 that faces the resolver stator 82 in the radial direction, and through which a wiring 84 (specifically, a harness) electrically connected to the coil 83 is inserted. The wiring 84 passes through the through hole 74a and is drawn from the inside to the outside of the bracket portion 70. The wiring 84 drawn to the outside passes through a space surrounded by the bracket portion 70 and the base portion 53, and is arranged along the direction in which the upper arm 23 extends.

[0047] A tubular sealing member 85 is provided between the through-hole 74a and the wiring 84. The sealing member 85 is made of, for example, a synthetic resin. The sealing member 85 prevents foreign matter from entering the inside of the bracket portion 70 through the gap between the through-hole 74a and the wiring 84.

[0048] The control device mounted on the vehicle is equipped with a resolver digital converter. The resolver digital converter supplies an excitation signal to an excitation coil included in the coil 83 via a wiring 84. The resolver digital converter also calculates an electrical angle by detecting signals from a pair of output coils included in the coil 83 and the excitation signal.

[0049] In this embodiment, the bracket portion 70 is made of a non-magnetic metal material, rather than a magnetic material such as iron, which prevents magnetic flux from leaking from the resolver stator 82 to the bracket portion 70, thereby improving the accuracy of calculating the electrical angle.

[0050] An opening of the main body 71 of the bracket part 70 on the inner side in the vehicle width direction is covered with a cover 100 (corresponding to "cover part"). The cover 100 is disk-shaped, and a plurality of bolt insertion holes 100a are formed at predetermined intervals on the periphery of the cover 100. Female threaded holes 73a, the same number as the bolt insertion holes 100a, are formed at predetermined intervals in the circumferential direction on the inner end part in the vehicle width direction of the thin-walled part 73. With the flat surface of the periphery of the cover 100 abutting the end face of the thin-walled part 73, a bolt 101 is inserted through the bolt insertion holes 100a and the female threaded hole 73a, and the male thread of the bolt 101 is screwed into the female threaded hole 73a. In this manner, the cover 100 is fixed to the bracket part 70.

[0051] A bolt insertion hole 21a is formed in the mounting portion 21 of the knuckle 20. A female threaded hole 100b is formed in the cover 100. With the mounting portion 21 abutting against the cover 100, a bolt 94 is inserted through the bolt insertion hole 21a and the female threaded hole 100b, and the male thread of the bolt 94 is screwed into the female threaded hole 100b. In this way, the cover 100 is fixed to the knuckle 20.

[0052] In this embodiment, the resolver 80 is covered by the bracket portion 70, thereby preventing foreign matter such as water and dust from entering the space surrounded by the bracket portion 70 from the outside. Here, an external force may act on the cover 100 due to vibrations or impacts from the road surface on which the vehicle is traveling, causing the cover 100 to deform. In this case, a gap may be generated between the cover 100 and the thin portion 73 of the bracket portion 70, and water or dust may enter the bracket portion 70 through the gap and adhere to the resolver 80. In this case, corrosion or deterioration of the resolver 80 may occur.

[0053] Therefore, in this embodiment, a structure is adopted that makes it difficult for water and dust to adhere to the resolver 80 even if a gap occurs between the cover 100 and the thin-walled portion 73 of the bracket portion 70. This structure will be described below with reference to Figs. 2 to 4. Fig. 3 is a view of the bracket portion 70 when the resolver 80, cover 100, seal cover 110, etc. are not attached, as viewed from the inside in the vehicle width direction. Fig. 4 is a view of the bracket portion 70 when the seal cover 110 is attached but the cover 100 is not attached, as viewed from the inside in the vehicle width direction.

[0054] The in-wheel motor 30 includes a seal cover 110 that closes the gap between the opening of the bracket portion 70 on the inner side in the vehicle width direction and the resolver rotor 81 and the resolver stator 82. The seal cover 110 is disk-shaped. The seal cover 110 may be made of a non-magnetic material (e.g., aluminum or synthetic resin) or a magnetic material (e.g., iron).

[0055] A plurality of (six) bolt insertion holes 110a are formed at a predetermined interval in the circumferential direction in the peripheral edge portion of the seal cover 110. As shown in FIG. 3, the first step portion 76 is formed with the same number of female threaded holes 76a as the bolt insertion holes 110a at a predetermined interval in the circumferential direction. In the first step portion 76, an annular groove 76b is formed radially inward of the female threaded holes 76a and extends over the entire circumferential direction. An elastic annular seal member 112 is disposed in the groove 76b as a sealant. In this embodiment, the seal member 112 is an O-ring.

[0056] With the seal member 112 pressed against the peripheral edge of the seal cover 110 and in a compressed state, and with the peripheral edge of the seal cover 110 abutting against the first step portion 76, the bolt 111 (corresponding to the "fixing portion") is inserted into the bolt insertion hole 110a and the female threaded hole 76a, and the male thread of the bolt 111 is screwed into the female threaded hole 76a. This fixes the seal cover 110 to the first step portion 76. This makes it possible to prevent water or dust from adhering to the resolver rotor 81 and the resolver stator 82, even if water or dust gets into the bracket portion 70 from the gap between the bracket portion 70 and the cover 100.

[0057] The radial thickness dimension of the intermediate portion 74 of the bracket portion 70 is larger than the radial thickness dimension of the thin portion 73 of the bracket portion 70. Therefore, the first step portion 76 is less likely to deform, and a gap is less likely to occur between the seal cover 110 and the first step portion 76. This effectively prevents water and dust from adhering to the resolver rotor 81 and the resolver stator 82.

[0058] The radial thickness of the thick portion 75 of the bracket portion 70 is greater than the radial thickness of the medium portion 74 of the bracket portion 70. This makes it difficult for the second step portion 77 to deform, and the coaxiality between the resolver stator 82 and the shaft 31 is unlikely to deteriorate. This improves the accuracy with which the resolver 80 detects the electrical angle.

[0059] <Modification of the first embodiment> A plurality of annular grooves 76b may be formed in the first step portion 76 and aligned in the radial direction. In this case, it is sufficient that a seal member 112 is disposed in each groove 76b.

[0060] The sealing member that seals between the seal cover 110 and the first step portion 76 is not limited to an O-ring, but may be, for example, an annular gasket (e.g., a metal gasket). In this case, the groove 76b does not need to be formed in the first step portion 76.

[0061] The sealing material is not limited to a sealing member, but may be, for example, a liquid gasket or an adhesive.

[0062] A portion of the main body 71 of the bracket part 70 that is inward in the vehicle width direction from the thin-walled part 73 may be a cover fitting part having an outer diameter dimension equal to that of the thin-walled part 73. The inner diameter dimension of the cover fitting part is larger than that of the thin-walled part 73, and the radial thickness dimension of the cover fitting part is smaller than that of the thin-walled part 73. In this case, it is sufficient that a female threaded hole 73a into which the male thread of the bolt 101 is screwed is formed in an annular stepped part between the thin-walled part 73 and the cover fitting part. The cover 100 is fixed to the bracket part 70 by the bolt 101 with the peripheral edge of the cover 100 abutting against the annular stepped part between the thin-walled part 73 and the cover fitting part.

[0063] Second Embodiment The second embodiment will be described below, focusing on the differences from the first embodiment, with reference to Fig. 5. In this embodiment, an elastic, annular outer seal member 102 is provided between the peripheral edge of the cover 100 and the thin-walled portion 73 of the bracket portion 70. The outer seal member 102 in this embodiment is an O-ring.

[0064] An annular groove 73b is formed over the entire circumferential area at the inner end in the vehicle width direction of the thin-walled portion 73, radially inward of the female threaded hole 73a. A seal member 102 is disposed in the groove 73b.

[0065] With the outer seal member 102 pressed against the peripheral edge of the cover 100 and in a compressed state, and with the peripheral edge of the cover 100 abutting against the annular end face on the inside in the vehicle width direction of the thin-walled portion 73, the bolt 101 is inserted through the bolt insertion hole 100 a and the female threaded hole 73 a, and the male thread of the bolt 101 is screwed into the female threaded hole 73 a. This fixes the cover 100 to the bracket portion 70.

[0066] According to the present embodiment described above, the intrusion of water and dust into the bracket portion 70 can be more reliably prevented.

[0067] <Modification of the second embodiment> A plurality of annular grooves 73b may be formed aligned in the radial direction at the inner end in the vehicle width direction of the thin-walled portion 73. In this case, it is sufficient that an outer seal member 102 is disposed in each groove 73b.

[0068] The outer sealing member that seals between the cover 100 and the bracket portion 70 is not limited to an O-ring, but may be, for example, an annular gasket (e.g., a metal gasket). In this case, the groove 73b does not need to be formed at the inner end of the thin-walled portion 73 in the vehicle width direction.

[0069] The outer sealing material is not limited to a sealing member, but may be, for example, a liquid gasket or an adhesive.

[0070] <Third embodiment> The third embodiment will be described below, focusing on differences from the first embodiment, with reference to Fig. 6. In this embodiment, instead of the cover 100, the mounting portion 21 (corresponding to the "cover portion") of the knuckle 20 covers the opening of the bracket portion 70 on the inner side in the vehicle width direction.

[0071] The mounting portion 21 has bolt insertion holes 21b, the same number as the female screw holes 73a, formed at predetermined intervals in the circumferential direction.

[0072] With the mounting portion 21 in contact with the bracket portion 70, the bolt 101 is inserted through the bolt insertion hole 21b and the female threaded hole 73a, and the male thread of the bolt 101 is screwed into the female threaded hole 73a. This fixes the bracket portion 70 to the knuckle 20.

[0073] According to the present embodiment described above, it is possible to reduce the number of components of the in-wheel motor 30 while closing the opening on the inner side of the bracket portion 70 in the vehicle width direction.

[0074] <Fourth embodiment> The fourth embodiment will be described below with reference to Figures 7 and 8, focusing on differences from the first embodiment. In this embodiment, an inner rotor type in-wheel motor 330 is used instead of an outer rotor type. Note that in this embodiment, descriptions of configurations similar to those of the first embodiment will be omitted as appropriate.

[0075] The in-wheel motor 330 includes a shaft 331 extending in the vehicle width direction, a rotor 340, and a stator 350 arranged radially outward of the rotor 340.

[0076] The rotor 340 includes a cylindrical magnet unit 341 and a rotor core 342 provided radially inside the magnet unit 341. Incidentally, the in-wheel motor 330 may be an embedded magnet type synchronous machine.

[0077] The stator 350 includes a cylindrical stator winding 351 disposed radially opposite the magnet unit 341, a cylindrical stator core 352 provided radially outward of the stator winding 351, and a base portion 353. The base portion 353 functions as a housing for the stator 350 and includes a cylindrical core mounting portion 354 extending in the vehicle width direction, and an annular portion 355 extending radially inward from the outer end of the core mounting portion 354 in the vehicle width direction. A through hole 356 through which the shaft 331 is inserted is formed in the center of the annular portion 355. The stator core 352 is attached to the radially outer end of the core mounting portion 354.

[0078] The in-wheel motor 330 includes a hub bearing 360 that rotatably supports the shaft 331 relative to the annular portion 355. The hub bearing 360 is a rolling bearing that includes a cylindrical outer ring 361, an inner ring 362, and a plurality of rolling elements 363 (e.g., balls) arranged between the outer ring 361 and the inner ring 362. An outer ring side flange portion of the outer ring 361 is fixed to the disc portion 12. The shaft 331 is fixed to the inner ring 362.

[0079] The in-wheel motor 330 includes a bracket portion 370. The bracket portion 370 includes a cylindrical main body portion 371 extending in the axial direction of the shaft 331, and an annular bracket-side flange portion 372 extending radially outward from the inner end portion in the vehicle width direction of the main body portion 371. The bracket-side flange portion 372 is fixed to the core mounting portion 354 with bolts 401.

[0080] Of the main body 371 of the bracket part 370, a portion of a first predetermined length in the axial direction from the opening on the outer side in the vehicle width direction is made into a thick-walled portion 375. Of the main body 371, a portion of a second predetermined length in the axial direction from the opening on the inner side in the vehicle width direction is made into a thin-walled portion 373 (corresponding to the "seal arrangement portion"). Of the main body 371, a portion between the thick-walled portion 375 and the thin-walled portion 373 is made into an intermediate-walled portion 374 (corresponding to the "sensor arrangement portion"). The inner diameter dimension of the intermediate-walled portion 374 is larger than the inner diameter dimension of the thick-walled portion 375, and the inner diameter dimension of the thin-walled portion 373 is larger than the inner diameter dimension of the intermediate-walled portion 374.

[0081] The boundary between thin portion 373 and medium-thickness portion 374 is a first step portion 376, and the boundary between medium-thickness portion 374 and thick portion 375 is a second step portion 377. First step portion 376 and second step portion 377 form an annular shape.

[0082] A resolver stator 382 constituting a resolver 380 is attached to the bracket portion 370 in a state where an end of the resolver stator 382 abuts against the second step portion 377 of the bracket portion 370 .

[0083] A resolver rotor 381 constituting a resolver 380 is attached to an inner end portion of a shaft 331 in the vehicle width direction. A small diameter portion 336, a large diameter portion 337, and a stepped portion 338 are formed on the shaft 331, which correspond to the small diameter portion 36, the large diameter portion 37, and the stepped portion 38 of the first embodiment. The resolver rotor 381 is attached to the shaft 331 in a state where the resolver rotor 381 is inserted into the small diameter portion 336 and an end portion of the resolver rotor 381 abuts against the stepped portion 338.

[0084] A through-hole 374a is formed in a portion of the intermediate portion 374 that faces the resolver stator 382 in the radial direction, and through which a wiring 384 (specifically, a harness) electrically connected to the coil 383 of the resolver stator 382 is inserted. The wiring 384 passes through the through-hole 374a and is drawn from the inside to the outside of the bracket portion 370. For convenience, a tubular seal member provided between the through-hole 374a and the wiring 384 is not shown in FIGS. 7 and 8.

[0085] An opening of the main body 371 of the bracket portion 370 on the inner side in the vehicle width direction is covered with a cover 400 (corresponding to "cover portion"). The cover 400 is disk-shaped, and a plurality of bolt insertion holes 400a are formed at predetermined intervals in the circumferential direction on the peripheral edge of the cover 400. Female threaded holes 372a, the same number as the bolt insertion holes 400a, are formed at predetermined intervals in the circumferential direction on the peripheral edge of the opening of the bracket-side flange portion 372. With the flat surface of the peripheral edge of the cover 400 abutting against the end face of the bracket-side flange portion 372, bolts 402 are inserted through the bolt insertion holes 400a and the female threaded holes 372a, and the male threads of the bolts 402 are screwed into the female threaded holes 372a. In this manner, the cover 400 is fixed to the bracket portion 370.

[0086] A female threaded hole 400b is formed in the cover 400. With the mounting portion 21 in contact with the cover 400, the bolt 94 is inserted through the bolt insertion hole 21a and the female threaded hole 400b, and the male thread of the bolt 94 is screwed into the female threaded hole 400b. This fixes the cover 400 to the knuckle 20.

[0087] The in-wheel motor 330 includes a seal cover 410 that closes the gap between the opening of the bracket portion 370 on the inner side in the vehicle width direction and the resolver rotor 381 and the resolver stator 382. The seal cover 410 is disk-shaped. The seal cover 410 may be made of a non-magnetic material (for example, aluminum or synthetic resin) or a magnetic material (for example, iron).

[0088] A plurality of bolt insertion holes 410a are formed at a predetermined interval in the circumferential direction on the peripheral edge of the seal cover 410. The first stepped portion 376 is formed with the same number of female threaded holes 376a as the bolt insertion holes 410a, also at a predetermined interval in the circumferential direction. A circular groove 376b is formed over the entire circumferential direction in the first stepped portion 376, radially inward of the female threaded holes 376a. An elastic circular seal member 412 is disposed in the groove 376b as a sealant. The seal member 412 in this embodiment is an O-ring.

[0089] With the seal member 412 pressed against the peripheral edge of the seal cover 410 and in a compressed state, and with the peripheral edge of the seal cover 410 abutting against the first stepped portion 376, the bolt 411 (corresponding to the "fixing portion") is inserted into the bolt insertion hole 410a and the female threaded hole 376a, and the male thread of the bolt 411 is screwed into the female threaded hole 376a. As a result, the seal cover 410 is fixed to the first stepped portion 376. As in the first embodiment, this makes it possible to prevent water or dust from adhering to the resolver rotor 381 and the resolver stator 382, ​​even if water or dust enters the bracket portion 370 through a gap between the bracket portion 370 and the cover 400.

[0090] <Other embodiments> The above-described embodiments may be modified as follows.

[0091] In the fourth embodiment, an outer sealant may be provided between the cover 400 and the bracket portion 370, as in the second embodiment.

[0092] The inner ring and shaft of the hub bearing may be configured as a single member.

[0093] The bracket portion and the base portion of the stator may be configured as a single component.

[0094] The position where the wiring 84 is drawn out is not limited to the position shown in Fig. 2, and for example, the wiring 84 may be drawn from the inside to the outside of the bracket portion 70 through a through-hole provided between the bracket portion 70 and the cover 100. Note that the through-hole is not limited to being at the inner end of the bracket portion 70 in the vehicle width direction, and may also be formed in the cover 100.

[0095] Furthermore, the wiring 84 may be drawn from the inside to the outside of the bracket portion 70 through a through-hole provided between the bracket-side flange portion 72 of the bracket portion 70 and the annular portion 55 of the stator 50 .

[0096] The bracket portion is not limited to a circular tube, but may be a rectangular tube such as a square or rectangular tube. The bracket portion may also be made of a magnetic material (for example, iron).

[0097] In the first to third embodiments, instead of the configuration in which the flat plate portion 43 of the in-wheel motor 30 is fixed to the disc portion 12 of the wheel 10, the magnet holding portion 41 of the in-wheel motor 30 may be fixed to the rim portion 11.

[0098] In the first to third embodiments, the rim portion 11 of the wheel 10 may serve as the magnet holding portion of the in-wheel motor 30, and the disc portion 12 may serve as the flat plate portion. In other words, the rotor 40 of the in-wheel motor 30 may serve as the wheel.

[0099] 1, a bearing that rotatably supports the inner end of the shaft 31 in the vehicle width direction may be attached to the inner peripheral surface of the bracket portion 70. In this case, the bearing may be provided, for example, closer to the cover 100 in the axial direction than the resolver 80.

[0100] The bracket portion may be made of a magnetic metal material (for example, soft magnetic iron).

[0101] The rotation angle sensor is not limited to a resolver, and may be, for example, a magnetic encoder having a magnet unit including a permanent magnet as a rotor-side sensor unit and a magnetic sensor including a Hall element as a bracket-side sensor unit.

[0102] The inverter may be built into the in-wheel motor.

[0103] The rotating electric machine is not limited to the radial gap type rotating electric machine shown in the first to fifth embodiments, but may be an axial gap type rotating electric machine.

[0104] The rotating electric machine may be a wound field type synchronous machine having a field winding on the rotor or stator instead of a permanent magnet synchronous machine.Furthermore, the rotating electric machine is not limited to a synchronous machine and may be, for example, an induction machine.

[0105] The wheeled mobile object equipped with an in-wheel motor may be an automated guided vehicle (AGV) or a forklift. The automated guided vehicle is, for example, an automatic guided vehicle (AGV) or an autonomous mobile robot (AMR) used in factories.

[0106] The wheeled mobile body equipped with an in-wheel motor may also be a small electric vehicle such as an electric wheelchair or a senior cart. A small electric vehicle is, for example, a vehicle with a travel speed of 10 km / h or less.

[0107] The following describes characteristic configurations extracted from the above-described embodiments. [Configuration 1] The present invention relates to an in-wheel motor (30, 330) that is applied to a vehicle equipped with a wheel (10) having a rim portion (11) to which a tire (13) can be attached and a disk portion (12) provided on a side surface of the rim portion, and that is at least partially housed in a wheel inner space surrounded by the disk portion and the rim portion and rotates the wheel, a tubular bracket portion (70, 370) extending in the vehicle width direction of the moving body; a stator (50, 350) connected to the bracket portion; a rotor (40, 340) having a shaft (31, 331) extending in the vehicle width direction and a field pole and connected to the wheel; a bearing (60, 360) that is provided on the outer side of the bracket portion in the vehicle width direction in the axial direction of the shaft and rotatably supports the shaft; Rotation angle sensor (80,380) Equipped with the shaft extends inward in the axial direction in the vehicle width direction to a position facing an inner circumferential surface of the bracket portion in the radial direction of the shaft, The rotation angle sensor a rotor-side sensor portion (81, 381) attached to the shaft at a position facing the inner circumferential surface of the bracket portion in the radial direction; a bracket-side sensor unit (82, 382) attached to an inner circumferential surface of the bracket unit at a position facing the rotor-side sensor unit in the radial direction of the shaft, the bracket-side sensor unit outputting a signal corresponding to the rotation angle of the rotor-side sensor unit; and the bracket portion is fixed to a cover portion (100, 400) fixed to a chassis portion (20) of the moving body, or a cover portion (21) constituting the chassis portion, in a state in which an opening portion on an inner side in the vehicle width direction of the bracket portion is closed by the cover portion (100, 400) fixed to the chassis portion (20) of the moving body, An in-wheel motor comprising a seal cover (110, 410) provided on the inner periphery of the bracket portion and sealing an opening on the inner side of the bracket portion in the vehicle width direction and a gap between the rotor-side sensor portion and the bracket-side sensor portion. [Configuration 2] The bracket portion is formed with a sensor arrangement portion (74, 374) in which the bracket-side sensor portion is arranged, and a seal arrangement portion (73, 373) that is adjacent to the sensor arrangement portion on the inner side in the vehicle width direction and has an inner diameter dimension larger than that of the sensor arrangement portion, 2. The in-wheel motor according to claim 1, wherein the seal cover is fixed to the bracket portion with the peripheral edge of the seal cover abutting against an annular step portion (76, 376) between the sensor arrangement portion and the seal arrangement portion in the bracket portion. [Configuration 3] 3. The in-wheel motor according to configuration 2, wherein a radial thickness dimension of the sensor arrangement portion of the bracket portion is greater than a radial thickness dimension of the seal arrangement portion of the bracket portion. [Configuration 4] The in-wheel motor according to configuration 2 or 3, wherein a seal (112, 412) is provided between the seal cover and the bracket. [Configuration 5] The step portion has an annular groove (76b, 376b) extending in the circumferential direction, The sealing material is an annular sealing member (112, 412), 5. The in-wheel motor according to claim 4, wherein the sealing member is disposed in the groove. [Configuration 6] 6. The in-wheel motor according to configuration 5, further comprising a fixing portion (111) that fixes a portion of the step portion radially outward from the groove to a peripheral edge portion of the seal cover. [Configuration 7] The in-wheel motor according to any one of configurations 1 to 6, wherein an outer seal (102) is provided between the inner end of the bracket in the vehicle width direction and the cover portion. [Configuration 8] The in-wheel motor according to any one of configurations 1 to 7, wherein the rotation angle sensor is a resolver having a resolver rotor as the rotor-side sensor portion, and an excitation winding and a resolver stator (82, 382) around which the excitation winding is wound as the bracket-side sensor portion. [Configuration 9] 9. The in-wheel motor according to configuration 8, wherein the bracket portion is made of a non-magnetic material.

[0108] 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. The in-wheel motor (30, 330) is applied to a moving body equipped with a wheel (10) having a rim portion (11) to which a tire (13) can be attached and a disk portion (12) provided on a side surface of the rim portion, and is at least partially housed in a wheel inner space surrounded by the disk portion and the rim portion and rotates the wheel, a tubular bracket portion (70, 370) extending in the vehicle width direction of the moving body; a stator (50, 350) connected to the bracket portion; a rotor (40, 340) having a shaft (31, 331) extending in the vehicle width direction and a field pole and connected to the wheel; a bearing (60, 360) that is provided on the outer side of the bracket portion in the vehicle width direction in the axial direction of the shaft and rotatably supports the shaft; A rotation angle sensor (80, 380); Equipped with the shaft extends inward in the axial direction in the vehicle width direction to a position facing an inner circumferential surface of the bracket portion in the radial direction of the shaft, The rotation angle sensor a rotor-side sensor portion (81, 381) attached to the shaft at a position facing the inner circumferential surface of the bracket portion in the radial direction; a bracket-side sensor unit (82, 382) attached to an inner circumferential surface of the bracket unit at a position facing the rotor-side sensor unit in the radial direction of the shaft, the bracket-side sensor unit outputting a signal corresponding to the rotation angle of the rotor-side sensor unit; and the bracket portion is fixed to a cover portion (100, 400) fixed to a chassis portion (20) of the moving body, or a cover portion (21) constituting the chassis portion, in a state in which an opening portion on an inner side in the vehicle width direction of the bracket portion is closed by the cover portion (100, 400) fixed to the chassis portion (20) of the moving body, An in-wheel motor comprising a seal cover (110, 410) provided on the inner periphery of the bracket portion and sealing the gap between an opening on the inner side of the bracket portion in the vehicle width direction and the rotor-side sensor portion and the bracket-side sensor portion.

2. The bracket portion is formed with a sensor arrangement portion (74, 374) in which the bracket-side sensor portion is arranged, and a seal arrangement portion (73, 373) that is adjacent to the sensor arrangement portion on the inner side in the vehicle width direction and has an inner diameter dimension larger than that of the sensor arrangement portion, 2. The in-wheel motor according to claim 1, wherein the seal cover is fixed to the bracket portion with the peripheral edge of the seal cover abutting against an annular step portion (76, 376) between the sensor arrangement portion and the seal arrangement portion in the bracket portion.

3. The in-wheel motor according to claim 2 , wherein a radial thickness dimension of the sensor arrangement portion of the bracket portion is greater than a radial thickness dimension of the seal arrangement portion of the bracket portion.

4. The in-wheel motor according to claim 2 or 3, wherein a seal (112, 412) is provided between the seal cover and the bracket.

5. The step portion has an annular groove (76b, 376b) formed therein and extending in the circumferential direction, The sealing material is an annular sealing member (112, 412), The in-wheel motor according to claim 4 , wherein the seal member is disposed in the groove.

6. The in-wheel motor according to claim 5, further comprising a fixing portion (111, 411) that fixes a portion of the step portion radially outward from the groove to a peripheral edge portion of the seal cover.

7. The in-wheel motor according to any one of claims 1 to 3, wherein an outer sealant (102) is provided between the inner end of the bracket in the vehicle width direction and the cover portion.

8. The rotation angle sensor a resolver rotor is provided as the rotor-side sensor unit, 4. The in-wheel motor according to claim 1, wherein the bracket-side sensor portion is a resolver including an excitation winding and a resolver stator (82, 382) around which the excitation winding is wound.

9. The in-wheel motor according to claim 8 , wherein the bracket portion is made of a non-magnetic material.

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