Drive device

Abstract

This drive device comprises: a motor (12) having a rotor (30) and a stator (40); a brake disk (50, 150); and an intermediate attachment part (60). The rotor has a carrier section (31) and a magnet section (32). The intermediate attachment part is provided at an end of the carrier section in the axial direction. The brake disk has a disk mounting part (52) and a sliding part (51). The intermediate attachment part has a base part (61) and an annular part (62, 90) extending from the base part to the brake disk side in the axial direction. The annular part has an annular part peripheral surface (62a, 90a) facing an attachment part peripheral surface (53a, 53b) of the disk attachment part in the radial direction. The drive device includes an axial-direction projection part (63, 163, 263) provided between the base part and the disk attachment part in the axial direction. The annular part peripheral surface contacts the attachment part peripheral surface, and the axial-direction protruding part is sandwiched between the disk attachment part and the base part.

Description

Drive unit CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2023-147144, filed on September 11, 2023, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a drive device including a motor having a rotor that rotates about a central axis of rotation extending in a predetermined axial direction and a stator that is arranged radially inside the rotor, and a brake disc.

[0003] Conventionally, a known drive device has an in-wheel motor structure in which at least a portion of the drive device is housed inside the wheel in the radial direction. In the in-wheel motor structure, a brake disc against which brake pads are pressed may be connected to the rotor of the motor. An example of such a technology is disclosed in Patent Document 1.

[0004] GB Patent Application Publication No. 2479898

[0005] The rotor has a cylindrical carrier and a magnet attached to the inner circumferential surface of the carrier. In a configuration in which a brake disc is connected to the rotor, there is a concern that heat generated by the brake disc may be transferred to the magnet of the rotor, which may result in a decrease in the magnetic flux density of the magnet.

[0006] The present disclosure has been made in consideration of the above circumstances, and its main object is to provide a drive device that can suppress heat transfer from the brake disc to the magnet portion of the rotor.

[0007] The present disclosure relates to a drive device comprising: a motor having a rotor that rotates around a central axis of rotation extending in a predetermined axial direction, and a stator that is arranged inside the rotor in a radial direction perpendicular to the axial direction; a brake disc; and an intermediate mounting portion connected to the rotor and the brake disc, wherein the rotor has a cylindrical carrier portion and a magnet portion provided on an inner peripheral surface of the carrier portion, the intermediate mounting portion having an annular shape in a circumferential direction extending circumferentially around the central axis of rotation, and is provided at an end of the carrier portion in the axial direction, the brake disc has: a disc mounting portion that is attached to the intermediate mounting portion and has an annular shape in the circumferential direction, and a sliding portion against which a brake pad is pressed, the disc mounting portion has a mounting portion peripheral surface along the circumferential direction, and the intermediate mounting portion has: a base portion that has an annular shape in the circumferential direction, and an annular portion that extends in the circumferential direction and from the base portion towards the brake disc in the axial direction, The annular portion has a peripheral surface of the annular portion that faces the peripheral surface of the mounting portion in the radial direction, and is provided with a plurality of axial protrusions that are arranged side by side in the circumferential direction between the base portion and the disk mounting portion in the axial direction, with the peripheral surface of the annular portion abutting the peripheral surface of the mounting portion, and each of the axial protrusions being sandwiched between the disk mounting portion and the base portion.

[0008] The brake disc is attached to the rotor via an intermediate mounting portion. The intermediate mounting portion is annular in the circumferential direction and is provided at the axial end of the carrier portion of the rotor. A magnet portion is provided on the inner circumferential surface of the carrier portion. In this case, there is a concern that heat generated in the sliding portion of the brake disc will be transferred to the magnet portion via the disc mounting portion, intermediate mounting portion, and carrier portion of the brake disc.

[0009] Therefore, in this disclosure, a structure for attaching a disc mounting portion to an intermediate mounting portion is provided with a plurality of axial protrusions arranged in a circumferential direction between the base portion and the disc mounting portion in the axial direction. Each axial protrusion is sandwiched between the disc mounting portion and the base portion in the axial direction. In this case, the contact area between the disc mounting portion and the intermediate mounting portion is reduced compared to when the disc mounting portion and the base portion are in direct surface contact. As a result, heat transfer from the brake disc to the rotor can be suppressed.

[0010] The disc mounting portion has a mounting portion circumferential surface along the circumferential direction. The intermediate mounting portion extends in the circumferential direction and has an annular portion that extends axially from the base portion toward the brake disc. The annular portion has an annular portion circumferential surface that faces the mounting portion circumferential surface in the radial direction. The annular portion circumferential surface abuts against the mounting portion circumferential surface. This makes it possible to ensure concentricity between the brake disc and the rotor.

[0011] According to the present disclosure described above, it is possible to ensure the concentricity of the brake disc and the rotor while suppressing heat transfer from the brake disc to the rotor.

[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 Fig. 1 is a longitudinal sectional view of a motor according to a first embodiment, Fig. 2 is a longitudinal sectional view of a brake disc and an intermediate mounting portion, Fig. 3 is a cross sectional view of the intermediate mounting portion, Fig. 4 is a cross sectional view of an intermediate mounting portion according to a second embodiment, Fig. 5 is a longitudinal sectional view of a brake disc and an intermediate mounting portion, Fig. 6 is a longitudinal sectional view of a brake disc and an intermediate mounting portion, Fig. 7 is a longitudinal sectional view of a brake disc and an intermediate mounting portion according to a third embodiment, Fig. 8 is a cross sectional view of a sub-base portion, Fig. 9 is a longitudinal sectional view of an intermediate mounting portion according to another embodiment, Fig. 10 is a longitudinal sectional view of an intermediate mounting portion according to another embodiment, Fig. 11 is a longitudinal sectional view of an intermediate mounting portion according to another embodiment, Fig. 12 is a longitudinal sectional view of an intermediate mounting portion according to another embodiment, Fig. 13 is a longitudinal sectional view of an intermediate mounting portion according to another embodiment, and Fig. 14 is a longitudinal sectional view of an intermediate mounting portion according to another embodiment.

[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 designated by 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 in which a drive device according to the present disclosure is embodied as a wheel unit will be described below with reference to Figures 1, 2, and 3. The wheel unit is used as a drive wheel in a vehicle such as a four-wheeled vehicle or a two-wheeled vehicle, and includes a wheel to which a tire is attached and a motor (in-wheel motor) housed in a space inside the wheel. The wheel unit of this embodiment is applied to an electrically powered vehicle such as an electric vehicle or a hybrid vehicle.

[0015] 1, the wheel unit 10 includes a cylindrical wheel 11 and a motor 12 that rotates the wheel 11. In the following description, the direction in which the rotational center axis LC of the motor 12 (wheel 11) extends is referred to as the axial direction, the direction extending radially from the center of the rotational center axis LC is referred to as the radial direction, and the direction extending circumferentially around the rotational axis is referred to as the circumferential direction.

[0016] The wheel 11 includes a tire 21 and a wheel 22 fixed to the inner periphery of the tire 21. The wheel 22 includes a hub 23 that serves as the center of rotation of the wheel 11, a cylindrical rim 24 that surrounds the hub 23, and spokes 25 that 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 motor 12 is housed in the inner space of the rim 24 (the inner space of the wheel 22). The motor 12 is provided in a fixed state to the hub 23 of the wheel 22.

[0017] The motor 12 is fixed to the inner periphery of the wheel 11. The motor 12 is an outer rotor surface permanent magnet motor, and includes a rotor 30 that rotates about a central rotation axis LC, and a stator 40 that is arranged radially inside the rotor 30. The stator 40 is fixed to the vehicle body 14, and the rotor 30 is fixed to the wheel 11. The rotor 30 and the stator 40 are each cylindrical, and are arranged opposite each other with an air gap that extends in an annular shape between them.

[0018] First, the configuration of the rotor 30 of the motor 12 will be described.

[0019] The rotor 30 has a substantially cylindrical carrier portion 31 and an annular magnet portion 32 fixed to the carrier portion 31. The carrier portion 31 functions as a magnet holding member and has a cylindrical portion 33 and an end plate portion 34 provided on one axial end of the cylindrical portion 33. The magnet portion 32 is fixed to the inner circumferential surface of the cylindrical portion 33. The other axial end of the carrier portion 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 portion 32. The carrier portion 31 is formed of a metal material such as iron or aluminum.

[0020] The magnet section 32 has a plurality of magnets fixed to the inner circumferential surface of the cylindrical section 33 of the carrier section 31. In the magnet section 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 polar-anisotropic permanent magnets, and are configured using, for example, 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 motor 12 may be an interior permanent magnet synchronous machine (IPMSM).

[0021] The wheel unit 10 includes a hub bearing 35. The hub bearing 35 includes an outer ring 35a as a stationary portion, an inner ring 35b as a rotating portion, and a plurality of rolling elements 35c (e.g., balls) disposed between the outer ring 35a and the inner ring 35b. The inner ring 35b is fixed to the inner surface of the end plate portion 34, which is one of the two axial faces that faces the cylindrical portion 33. The inner ring 35b, the hub 23, and the end plate portion 34 are fixed to one another with fasteners such as bolts. This allows the rotor 30 to be assembled to the wheel 11, allowing the rotor 30 and the wheel 22 to rotate integrally.

[0022] Next, the configuration of the stator 40 will be described.

[0023] The stator 40 includes 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.

[0024] 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. For example, the stator winding 41 can be configured with three phase windings of U, V, and W phases. The stator core 42 is cylindrical and is provided as a back yoke.

[0025] For example, the stator 40 may have 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 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 portion 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 member. (C) A structure in which no inter-conductor members are provided between each conductor portion in the circumferential direction in the stator 40.

[0026] The stator holder 43 has a cylindrical portion 44 assembled to the radially inner side of the stator core 42, and an end plate portion 45 provided radially inner on one axial end side of the cylindrical portion 44. The stator holder 43 has the end plate portion 45 provided on the same side as the end plate portion 34 of the carrier portion 31, of both axial sides. As a result, the carrier portion 31 and the stator holder 43 are configured such that the end plate portions 34, 45 face each other on one axial side and are open on the other side.

[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 motor 12 as the pump is driven.

[0028] The holder end plate portion 45 extends radially inward from the cylindrical portion 44 to the hub bearing 35, and serves as a partition plate portion that axially divides the inner space of the cylindrical portion 44. For example, the holder end plate portion 45 has a plurality of holes into which the outer ring 35a of the hub bearing 35 is assembled.

[0029] The stator 40 includes a support portion 48 that supports the stator holder 43. The support portion 48 is provided on the inner circumferential side of the cylindrical portion 44 of the stator holder 43. The support portion 48 is fixed to the vehicle body 14. As a result, the motor 12 is mounted on the vehicle so that the rotational center axis LC of the rotor 30 extends in the horizontal direction.

[0030] Next, the configuration of the brake device 13 and its surroundings will be described.

[0031] The wheel unit 10 includes a brake disc 50 and an intermediate mounting portion 60 that constitute the brake device 13. The intermediate mounting portion 60 is a member for mounting the brake disc 50 to the expanded diameter portion 33b of the rotor 30. The brake device 13 is a disc-type friction braking device. The brake disc 50 is a solid disc made of a single circular plate, or a ventilated disc having a cavity inside for ventilation.

[0032] Although detailed explanation using drawings will be omitted, the brake device 13 has a brake caliper. The brake caliper is actuated by hydraulic pressure, an electric signal, or the like, and has a pair of brake pads that come into contact with the brake disc 50 to generate a braking force, a piston that presses the brake pads against the brake disc 50, and a caliper body that supports the brake pads and the piston.

[0033] The brake disc 50 has an annular shape in the circumferential direction about the central axis of rotation LC, and includes a sliding portion 51 against which a brake pad is pressed, and a disc mounting portion 52 for mounting the brake disc 50 to the intermediate mounting portion 60. In this embodiment, the sliding portion 51 is provided radially outside the disc mounting portion 52. The motor 12, the brake disc 50, and the intermediate mounting portion 60 correspond to a "drive device."

[0034] An intermediate mounting portion 60 is fixed to one axial end of the magnet holding portion 33a of the rotor 30 by a fastener such as a bolt (not shown). The intermediate mounting portion 60 has an annular shape in the circumferential direction about the central axis of rotation LC. A radially inner portion of the intermediate mounting portion 60 is attached to the support portion 48 via the bearing 36.

[0035] The bearing 36 is a radial ball bearing having an outer ring 36a, an inner ring 36b, and a plurality of balls 36c arranged between them. A radially inner portion of an intermediate mounting part 60 is fixed to the outer ring 36, and a support part 48 is fixed to the inner ring 36b. The rotor 30 is rotatably supported by the hub bearing 35 and the bearing 36 relative to the stator holder 43 and the support part 48.

[0036] Here, in a configuration in which the brake disc 50 is attached to the rotor 30 via the intermediate attachment portion 60, there is a concern that heat generated in the sliding portion 51 will be transferred to the magnet portion 32 via the disc attachment portion 52, the intermediate attachment portion 60, and the carrier portion 31. In this case, there is a concern that the magnetic flux density of the magnet portion 32 will decrease.

[0037] Therefore, the wheel unit 10 according to this embodiment has a characteristic configuration for suppressing heat transfer from the brake disc 50 to the rotor 30. This characteristic configuration will be described below with reference to Figures 2 and 3. Figure 2 is a longitudinal cross-sectional view of the brake disc 50 and the intermediate mounting portion 60, and Figure 3 is a transverse cross-sectional view of the intermediate mounting portion 60. Figure 2 is a cross-sectional view taken along line 2-2 in Figure 3, and Figure 3 is a cross-sectional view taken along line 3-3 in Figure 2.

[0038] As shown in FIGS. 2 and 3, the intermediate mounting portion 60 has a base portion 61 that is annular in shape in the circumferential direction about the central rotation axis LC.

[0039] A plurality of female screw holes 61 a are formed at predetermined intervals in the circumferential direction in the base portion 61 of the intermediate mounting portion 60. In this embodiment, eight female screw holes 61 a are formed at equal intervals.

[0040] A bolt insertion hole 52a is formed in the disc mounting portion 52 of the brake disc 50, penetrating in the axial direction. A bolt 70 is inserted into the bolt insertion hole 52a and the female threaded hole 61a, and the male thread formed on the shank of the bolt 70 is screwed into the female thread formed in the female threaded hole 61a. In this way, the brake disc 50 is mounted to the intermediate mounting portion 60. Note that in Figure 3, a portion of the base portion 61 radially outward from the female threaded hole 61a is not shown.

[0041] The intermediate mounting portion 60 extends circumferentially along the radially inner end of the base portion 61, and has an annular portion 62 that extends axially from the base portion 61 toward the brake disc 50. The annular portion 62 is located radially inward of the disc mounting portion 52.

[0042] The intermediate mounting portion 60 has an axial protruding portion 63 formed integrally with the base portion 61. The axial protruding portion 63 protrudes in the axial direction from a portion of the base portion 61 radially outward from the annular portion 62 to the disc mounting portion 52. A plurality of axial protruding portions 63 are provided and aligned in the circumferential direction. In this embodiment, as shown in FIG. 3 , the axial protruding portion 63 is cylindrical and surrounds each female screw hole 61 a. This allows the fastening point of the bolt 70 to be reused as the axial protruding portion 63.

[0043] A through-hole 53 that penetrates the disc mounting portion 52 in the axial direction is formed in the radial center of the disc mounting portion 52. The annular portion 62 of the intermediate mounting portion 60 is fitted into the through-hole 53, with each axial protrusion 63 abutting against the disc mounting portion 52. In this case, each axial protrusion 63 is sandwiched between the disc mounting portion 52 and the base portion 61. This reduces the contact area between the disc mounting portion 52 and the intermediate mounting portion 60 compared to when the disc mounting portion 52 and the base portion 61 are in direct surface contact. This makes it possible to suppress heat transfer from the brake disc 50 to the rotor 30.

[0044] The disc mounting portion 52 has a mounting portion peripheral surface 53a along the circumferential direction. The mounting portion peripheral surface 53a is the inner peripheral surface of the through hole 53. The annular portion 62 has an annular portion peripheral surface 62a, which is an outer peripheral surface facing the mounting portion peripheral surface 53a in the radial direction. The intermediate mounting portion 60 is fitted into the through hole 53 with the annular portion peripheral surface 62a abutting against the mounting portion peripheral surface 53a. This makes it possible to ensure coaxiality between the brake disc 50 and the rotor 30. As a result, according to this embodiment, it is possible to ensure coaxiality between the brake disc 50 and the rotor 30 while suppressing heat transfer from the brake disc 50 to the magnet portion 32 of the rotor 30.

[0045] In this embodiment, each axial protrusion 63 is integrally formed with the base portion 61. This makes it possible to reduce the number of steps required to process the disc mounting portion 52 while also realizing a configuration that suppresses heat transfer from the brake disc 50 to the rotor 30. As a result, even when a general-purpose brake disc 50 is used, heat transfer can be suppressed.

[0046] The annular portion 62 has radial protrusions 64 that protrude radially outward. A plurality of radial protrusions 64 are provided and aligned in the circumferential direction. The annular portion circumferential surface 62a is the outer circumferential surface of each radial protrusion 64. The annular portion circumferential surface 62a is located on a concentric circle centered on the central rotation axis LC. In this embodiment, each radial protrusion 64 is provided at the same circumferential position as the axial protrusion 63. Each radial protrusion 64 is separated from the axial protrusion 63 in the radial direction.

[0047] In Figure 3, the mounting portion circumferential surface 53a is indicated by a dashed line. That is, the through-hole 53 is formed radially inward from the dashed line in Figure 3. The annular portion circumferential surface 62a abuts against the mounting portion circumferential surface 53a. Meanwhile, at locations on the outer circumferential surface of the annular portion 62 where the radial protrusions 64 are not provided, a gap is provided between the outer circumferential surface of the annular portion 62 and the mounting portion circumferential surface 53a. In this case, the contact area between the disc mounting portion 52 and the intermediate mounting portion 60 can be reduced in the radial direction compared to when the entire outer circumferential surface of the annular portion 62 abuts against the mounting portion circumferential surface 53a. Therefore, heat transfer from the brake disc 50 to the magnet portion 32 of the rotor 30 can be effectively suppressed.

[0048] To allow the annular portion circumferential surface 62a to abut against the mounting portion circumferential surface 53a, the axial dimension L1 of the annular portion 62 relative to the base portion 61 is greater than the axial dimension L2 of each axial protruding portion 63 relative to the base portion 61. In this configuration, the radial protruding portions 64 and the axial protruding portions 63 are radially spaced apart. Furthermore, an inner portion 54 of the disc mounting portion 52, which is radially inward of the axial protruding portions 63, is axially spaced apart from a narrow portion 65 of the base portion 61 between the axial protruding portions 63 and the radial protruding portions 64. In this case, a gap is formed between the inner portion 54 of the disc mounting portion 52 and the narrow portion 65 of the base portion 61. This allows air to be sent into the gap between the inner portion 54 and the narrow portion 65 as the rotor 30 rotates. As a result, heat generated in the brake disc 50 can be efficiently dissipated to the outside.

[0049] Second Embodiment A second embodiment will now be described with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, the configuration of the intermediate mounting portion 60 is changed.

[0050] The intermediate mounting portion 60 will be described below with reference to Figures 4, 5, and 6. Figure 4 is a cross-sectional view taken along line 6-6 in Figures 5 and 6. Figure 5 is a cross-sectional view taken along line 5-5 in Figure 4, and Figure 6 is a cross-sectional view taken along line 6-6 in Figure 4. For convenience, the same reference numerals are used in Figures 4 to 6 to designate the same components as those shown in Figures 2 and 3.

[0051] As shown in Fig. 4, each axial protruding portion 63 is provided at a position offset in the circumferential direction relative to each radial protruding portion 64. In this embodiment, the axial protruding portion 63 and the female screw hole 61a are provided at the center position of two radial protruding portions 64 adjacent to each other in the circumferential direction. Note that the axial protruding portion 63 and the female screw hole 61a may be provided closer to one of the two radial protruding portions 64 adjacent to each other in the circumferential direction. In this case, it is preferable that the axial protruding portions 63 and the radial protruding portions 64 do not overlap in the radial direction.

[0052] In the circumferential direction, no radial protrusions 64 are provided at locations where the axial protrusions 63 are provided. In this case, as shown in Figure 5, the axial protrusions 63 abut against the disk mounting portion 52, and the mounting portion peripheral surface 53a and the outer peripheral surface of the annular portion 62 are spaced apart.

[0053] Meanwhile, in the circumferential direction, radial protrusions 64 are provided in locations where no axial protrusions 63 are provided. In this case, as shown in Figure 6, the disk mounting portion 52 and the base portion 61 are spaced apart in the axial direction, and the mounting portion peripheral surface 53a and the annular portion peripheral surface 62a abut against each other in the radial direction.

[0054] According to this embodiment, the axial protruding portions 63 are provided at positions offset in the circumferential direction relative to the radial protruding portions 64, so that the contact points between the disc mounting portion 52 and the intermediate mounting portion 60 are distributed circumferentially. This allows heat generated at the sliding portion 51 of the brake disc 50 to be distributed circumferentially between the disc mounting portion 52 and the intermediate mounting portion 60. Therefore, heat generated at the sliding portion 51 of the brake disc 50 can be suitably dissipated to the outside from the disc mounting portion 52 to the intermediate mounting portion 60, and heat transfer from the brake disc 50 to the rotor 30 can be appropriately suppressed.

[0055] Third Embodiment A third embodiment will be described below with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, the intermediate mounting portion 60 has a sub-base portion that is a separate member from the base portion 61. Note that, here, the base portion 61 having the axial protrusion 63 is referred to as the “main base portion 61.”

[0056] The main base portion 61 and the sub-base portion 80 will be described below with reference to Figures 7 and 8. Figure 7 is a cross-sectional view taken along line 7-7 in Figure 8, and Figure 8 is a cross-sectional view taken along line 8-8 in Figure 7. For convenience, the same components as those shown in Figure 2 are denoted by the same reference numerals in Figure 7.

[0057] The sub-base portion 80 has an annular shape in the circumferential direction, and is laminated in only one layer on the rotor 30 side of the main base portion 61 in the axial direction. In this case, the sub-base portion 80 is fixed to the expanded diameter portion 33b of the carrier portion 31 with a fastener such as a bolt. The number of laminated layers of the sub-base portion 80 is not limited to one, and may be multiple.

[0058] A plurality of sub-female threaded holes 81 are formed in the sub-base portion 80 at predetermined intervals in the circumferential direction. Each sub-female threaded hole 81 is formed at the same position in the radial and circumferential directions as the female threaded hole 61a of the main base portion 61. A bolt 70 is inserted into the bolt insertion hole 52a, the female threaded hole 61a, and the sub-female threaded hole 81, and the male threads formed on the bolt 70 are screwed into the female threads formed in the female threaded hole 61a and the sub-female threaded hole 81. In this case, the bolt 70 attaches the brake disc 50 to the intermediate mounting portion 60, and also connects the main base portion 61 and the sub-base portion 80 to each other.

[0059] The intermediate mounting portion 60 has a sub-protrusion 82 formed integrally with the sub-base portion 80. The sub-protrusion 82 protrudes in the axial direction from the sub-base portion 80 to the main base portion 61. This causes the sub-protrusion 82 to abut against the main base portion 61 in the axial direction. In this case, the contact area between the base portion 61 and the sub-base portion 80 is reduced compared to when the base portion 61 and the sub-base portion 80 are in direct surface contact. Therefore, the intermediate mounting portion 60 can be more effectively prevented from transmitting heat from the brake disc 50 side to the rotor 30 side.

[0060] In this embodiment, a plurality of sub-projections 82 are provided lined up in the circumferential direction. The sub-projections 82 are provided for each sub-female screw hole 81 so as to surround the sub-female screw hole 81.

[0061] The main base portion 61 and the sub-base portion 80 may be configured to abut against each other in the radial direction. Specifically, a circular recess 66 recessed in the axial direction may be formed in the radial center of one of the axially opposite surfaces of the main base portion 61 facing the sub-base portion 80. Furthermore, a sub-annular portion 83 having an axial dimension larger than that of the sub-projection portion 82 may be formed in the radial center of the sub-base portion 80. In this case, the sub-annular portion 83 is fitted into the recess 66 with the inner circumferential surface 66a of the recess 66 and the outer circumferential surface 83a of the sub-annular portion 83 abutting against each other in the radial direction. This makes it possible to ensure coaxiality between the brake disc 50 and the rotor 30 even in a structure in which the intermediate mounting portion 60 is divided into the base portion 61 and the sub-base portion 80.

[0062] 8, the radial end of the main base portion 61 is indicated by a dashed line. That is, the recessed portion 66 is formed radially inward of the dashed line in FIG.

[0063] The sub-base portion 80 may be formed with a protrusion 84 that protrudes radially outward from the sub-annular portion 83. In this case, the inner peripheral surface 66a of the recessed portion 66 abuts against the outer peripheral surface 83a of the sub-annular portion 83 at a location where the protrusion 84 is provided. This makes it possible to reduce the contact area between the base portion 61 and the sub-base portion 80 in the radial direction compared to when the entire outer peripheral surface of the sub-annular portion 83 abuts against the inner peripheral surface 66a of the recessed portion 66.

[0064] Other Embodiments The above-described embodiments may be modified as follows.

[0065] The outer dimensions of the tip end of each axial protruding portion 63 may become smaller as it approaches the tip end of each axial protruding portion 63. For example, as shown in Fig. 9, the outer dimensions of the tip end of each axial protruding portion 63 may be reduced by forming the tip end of each axial protruding portion 63 into a tapered shape. Furthermore, for example, as shown in Fig. 10, the outer dimensions of the tip end of each axial protruding portion 63 may be reduced by forming the tip end of each axial protruding portion 63 into a curved shape (i.e., an R-shape).

[0066] According to this embodiment, the outer dimensions of the tip end of each axial protrusion 63 are reduced. This reduces the contact area between the disk mounting portion 52 and the intermediate mounting portion 60, and effectively suppresses heat transfer from the disk mounting portion 52 to each axial protrusion 63 in the axial direction.

[0067] The outer dimensions of the annular portion 62 may become smaller as it moves from the base portion 61 toward the brake disc 50. For example, as shown in Figures 9 and 10, the outer dimensions of the tip of the annular portion 62 may be reduced by tapering the shape of each radial protrusion 64 of the annular portion 62. The tapered shape of the tip of each radial protrusion 64 makes it easier for the annular portion 62 to fit into the through hole 53, improving the ease of assembly of the brake disc 50 and the intermediate mounting portion 60.

[0068] According to this embodiment, the outer dimensions of the tip of the annular portion 62 are reduced. This reduces the contact area between the mounting portion circumferential surface 53a and the annular portion circumferential surface 62a, thereby effectively suppressing heat transfer in the radial direction from the disk mounting portion 52 to each radial protrusion 64. Note that the contact area between the mounting portion circumferential surface 53a and the annular portion circumferential surface 62a can also be reduced by forming each radial protrusion 64 of the annular portion 62 into a curved shape.

[0069] In the first embodiment, as shown in FIG. 11 , the annular portion 90 may extend circumferentially along the radially outer end of the base portion 61, radially outward of the disk mounting portion 52. The disk mounting portion 52 may have a mounting portion circumferential surface 53b, which is the outer peripheral surface on the radially outer side. The annular portion 90 may have a ring-shaped portion circumferential surface 90a, which is the inner peripheral surface facing the mounting portion circumferential surface 53b. In this case, the ring-shaped portion circumferential surface 90a abuts against the mounting portion circumferential surface 53b. Note that the second embodiment, the third embodiment, and the other embodiments described above may employ a configuration in which the ring-shaped portion circumferential surface 90a abuts against the mounting portion circumferential surface 53b according to this embodiment.

[0070] In this embodiment, a plurality of annular portions 90 may be arranged in a circumferential direction and may have radial protrusions that protrude radially inward. In this case, the annular portion circumferential surface 90a is the inner circumferential surface of the radial protrusions. Alternatively, the annular portion 90 may not have a radial protrusion. In this case, the annular portion circumferential surface 90a is the entire circumference of the inner circumferential surface of the annular portion 90.

[0071] In the first embodiment, as shown in Fig. 12, the sliding portion 151 of the brake disc 150 may be provided radially inside the disc mounting portion 52. Note that a similar configuration may also be adopted in the second embodiment, the third embodiment, and the other embodiments described above.

[0072] In the first embodiment, the axial protrusions are not limited to those formed integrally with the base portion 61. For example, as shown in FIG. 13 , the axial protrusions 163 may be formed integrally with the disc mounting portion 52. In this case, it is sufficient that the axial protrusions 163 protrude in the axial direction from the disc mounting portion 52 to a portion of the base portion 61 that is radially outward of the annular portion 62. In the present embodiment, the annular portion 62 of the intermediate mounting portion 60 is fitted into the through hole 53 with the axial protrusions 163 abutting against the base portion 61.

[0073] 14 , for example, the axial protrusions 263 may be provided as separate members from the base portion 61 and the disk mounting portion 52. In this embodiment, the annular portion 62 of the intermediate mounting portion 60 is fitted into the through hole 53 with the axial protrusions 263 abutting against the disk mounting portion 52 and the base portion 61.

[0074] In other words, when one of the portion of the base portion 61 radially outward from the annular portion 62 and the disc mounting portion 52 is defined as a first portion and the other is defined as a second portion, each axial protruding portion may protrude in the axial direction from the first portion to the second portion. Note that in the second embodiment, the third embodiment, and the above-mentioned other embodiments, each axial protruding portion may be formed integrally with the base portion 61 or may be provided as a separate member from the base portion 61 and the disc mounting portion 52.

[0075] Each axial protrusion does not have to be provided for each female screw hole 61a.

[0076] Each axial protrusion does not have to be provided so as to surround the female screw hole 61a.

[0077] The axial protruding portions may be provided at positions other than the female screw holes 61 a. For example, the axial protruding portions may be provided at intermediate positions between two female screw holes 61 a that are adjacent in the circumferential direction. In this case, the axial protruding portions and the radial protruding portions may be provided at the same positions in the circumferential direction as described in the first embodiment, or may be provided at positions offset from each other as described in the second embodiment.

[0078] Furthermore, for example, the axial protrusion may be substantially C-shaped with a portion of the annular portion surrounding the female screw hole 61a missing.

[0079] In the third embodiment, each sub-projection is not limited to being formed integrally with the sub-base portion 80, and may be formed integrally with the main base portion 61. In this case, it is sufficient that the sub-projection projects in the axial direction from the main base portion 61 to the sub-base portion 80. In other words, it is sufficient that the sub-projection 82 projects in the axial direction from the third portion, which is either the main base portion 61 or the sub-base portion 80, to the fourth portion, which is the other.

[0080] In the third embodiment, like the axial protrusions, each sub-protrusion does not have to be provided for each sub-female screw hole 81, and does not have to be provided so as to surround the sub-female screw hole 81. Furthermore, each sub-protrusion can be provided at a position other than the sub-female screw hole 81. Figure 8 shows an example in which a sub-protrusion 82 is also provided at the radially outer end of the sub-base portion 80.

[0081] A gap is provided between the disk mounting portion 52 and a portion of the base portion 61 that faces the disk mounting portion 52 in the axial direction and that does not have any of the axial protruding portions 63. In this configuration, a heat insulating material made of ceramic or synthetic resin may be sandwiched between the disk mounting portion 52 and the base portion 61.

[0082] The annular portion 62 does not have to be provided with a radial protrusion. In this case, the entire outer circumferential surface of the annular portion 62 is the annular portion circumferential surface.

[0083] The intermediate attachment portion 60 does not necessarily have to be fixed as a separate member to one axial end of the rotor 30 , but may be formed integrally with the rotor 30 .

[0084] The motor may be used for purposes other than a vehicle traction motor, and may be used in a wide range of moving objects including aircraft and ships.

[0085] 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.

[0086] The following describes characteristic configurations extracted from the above-described embodiments. [Configuration 1] A drive device comprising: a motor (12) having a rotor (30) that rotates about a central axis of rotation extending in a predetermined axial direction, and a stator (40) arranged inside the rotor in a radial direction perpendicular to the axial direction; a brake disc (50, 150); and an intermediate mounting portion (60) connected to the rotor and the brake disc, wherein the rotor has a cylindrical carrier portion (31) and a magnet portion (32) provided on an inner peripheral surface of the carrier portion, and the intermediate mounting portion has an annular shape in a circumferential direction extending circumferentially around the central axis of rotation, and is provided at an end of the carrier portion in the axial direction, and the brake disc has: a disc mounting portion (52) that is attached to the intermediate mounting portion and has an annular shape in the circumferential direction, and a sliding portion (51) against which a brake pad is pressed, and the disc mounting portion has mounting portion peripheral surfaces (53a, 53b) along the circumferential direction, and the intermediate mounting portion has a base portion (61) having an annular shape in the circumferential direction, and an annular portion (62, 90) extending in the circumferential direction and from the base portion toward the brake disc in the axial direction, wherein the annular portion has an annular portion circumferential surface (62a, 90a) facing the mounting portion circumferential surface in the radial direction, and a plurality of axial protruding portions (63, 163, 263) provided side by side in the circumferential direction between the base portion and the disc mounting portion in the axial direction, wherein the annular portion circumferential surface abuts on the mounting portion circumferential surface, and each of the axial protruding portions is sandwiched between the disc mounting portion and the base portion. [Configuration 2] The drive device according to Configuration 1, wherein the mounting portion circumferential surface is an inner circumferential surface (53a) on the radially inner side of the disc mounting portion, and the annular portion (62) extends in the circumferential direction along an inner end of the base portion in the radial direction, radially inner than the disc mounting portion. [Configuration 3] The drive device according to Configuration 2, wherein the annular portion has a plurality of radial protruding portions (64) arranged side by side in the circumferential direction and protruding radially outward, and the peripheral surface of the annular portion is the outer peripheral surface (62 a) of the radial protruding portion.[Configuration 4] The drive device according to Configuration 3, wherein the radial protrusions and the axial protrusions are spaced apart in the radial direction, the axial dimension (L1) of the annular portion relative to the base portion is greater than the axial dimension (L2) of each of the axial protrusions relative to the base portion, and a portion (54) of the disk mounting portion that is radially inward from each of the axial protrusions and a portion (65) of the base portion that is radially between each of the axial protrusions are spaced apart in the axial direction to form a gap. [Configuration 5] The drive device according to Configuration 3 or 4, wherein the axial protrusions are provided at positions offset from each of the radial protrusions in the circumferential direction. [Configuration 6] The drive device according to any one of configurations 1 to 5, wherein the intermediate mounting portion has a sub-base portion (80) that is a separate member from the base portion, the sub-base portion having an annular shape in the circumferential direction and being stacked closer to the rotor than the base portion in the axial direction, and the intermediate mounting portion has a sub-projecting portion (82) that projects in the axial direction from a third portion that is one of the base portion and the sub-base portion to a fourth portion that is the other of the base portion and the sub-base portion. [Configuration 7] The drive device according to any one of configurations 1 to 6, wherein a tip end portion of the axial projecting portion has an outer dimension that decreases as it approaches the tip end of the axial projecting portion. [Configuration 8] The drive device according to any one of configurations 1 to 7, wherein the outer dimension of the annular portion decreases as it approaches from the base portion toward the brake disc. [Configuration 9] The drive device of any one of configurations 1 to 8, wherein the disk mounting portion has a bolt insertion hole (52) penetrating in the axial direction, the base portion has a female threaded hole (61a) penetrating in the axial direction, a male thread formed on a shank of a bolt (70) to be inserted into the bolt insertion hole is screwed into the female threaded hole, and the axial protruding portion is provided so as to surround the bolt insertion hole and the female threaded hole. [Configuration 10] The drive device of any one of configurations 1 to 9, wherein the axial protruding portion is integrally formed with the base portion, integrally formed with the disk mounting portion, or provided as a separate member from the base portion and the disk mounting portion.[Configuration 11] The drive device according to any one of configurations 1 to 10, wherein the motor is an in-wheel motor.

[0087] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and equivalent modifications. In addition, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

Claims

1. A drive device comprising: a motor (12) having a rotor (30) rotating about a central axis of rotation extending in a predetermined axial direction, and a stator (40) arranged inside the rotor in a radial direction perpendicular to the axial direction; a brake disc (50, 150); and an intermediate mounting portion (60) connected to the rotor and the brake disc, wherein the rotor has a cylindrical carrier portion (31) and a magnet portion (32) provided on an inner peripheral surface of the carrier portion, and the intermediate mounting portion forms an annular shape in a circumferential direction extending circumferentially around the central axis of rotation, and is provided at an end of the carrier portion in the axial direction, and the brake disc has: a disc mounting portion (52) attached to the intermediate mounting portion and forming an annular shape in the circumferential direction, and a sliding portion (51) against which a brake pad is pressed, and the disc mounting portion has a mounting portion peripheral surface (53a, 53b) along the circumferential direction, and the intermediate mounting portion is a base portion (61) having a circular ring shape in the circumferential direction; and an annular portion (62, 90) extending in the circumferential direction and extending from the base portion toward the brake disc in the axial direction, wherein the annular portion has an annular portion circumferential surface (62a, 90a) that faces the mounting portion circumferential surface in the radial direction, and a plurality of axial protruding portions (63, 163, 263) are provided side by side in the circumferential direction between the base portion and the disc mounting portion in the axial direction, wherein the annular portion circumferential surface abuts against the mounting portion circumferential surface, and each of the axial protruding portions is sandwiched between the disc mounting portion and the base portion.

2. A drive device as described in claim 1, wherein the mounting portion circumferential surface is the radially inner inner surface (53a) of the disk mounting portion, and the annular portion (62) extends in the circumferential direction along the radially inner end portion of the base portion, radially inner than the disk mounting portion.

3. A drive unit as described in claim 2, wherein the annular portion has a plurality of radial protruding portions (64) arranged side by side in the circumferential direction and protruding radially outward, and the peripheral surface of the annular portion is the outer circumferential surface (62a) of the radial protruding portion.

4. A drive device as described in claim 3, wherein each of the radial protrusions and each of the axial protrusions are spaced apart in the radial direction, the axial dimension (L1) of the annular portion relative to the base portion is greater than the axial dimension (L2) of each of the axial protrusions relative to the base portion, and a portion (54) of the disk mounting portion that is radially inward from each of the axial protrusions and a portion (65) of the base portion between each of the axial protrusions in the radial direction are spaced apart in the axial direction with a gap therebetween.

5. A drive device according to claim 3 or 4, wherein each of said axial protruding portions is provided at a position offset from each of said radial protruding portions in the circumferential direction.

6. A drive device as claimed in any one of claims 1 to 4, wherein the intermediate mounting portion has a sub-base portion (80) which is a separate member from the base portion, the sub-base portion having an annular shape in the circumferential direction and being stacked on the rotor side of the base portion in the axial direction, and the intermediate mounting portion has a sub-projection portion (82) which projects in the axial direction from a third portion which is either the base portion or the sub-base portion to a fourth portion which is the other of the base portion and the sub-base portion.

7. A drive unit according to any one of claims 1 to 4, wherein the outer dimensions of the tip of the axial protrusion become smaller the closer to the tip of the axial protrusion.

8. A drive device according to any one of claims 1 to 4, wherein the outer dimensions of the annular portion decrease from the base portion toward the brake disc.

9. A drive device as described in any one of claims 1 to 4, wherein a bolt insertion hole (52) penetrating in the axial direction is formed in the disk mounting portion, a female threaded hole (61a) penetrating in the axial direction is formed in the base portion, a male screw formed on the shank of a bolt (70) inserted into the bolt insertion hole is screwed into the female threaded hole, and the axial protrusion is arranged to surround the bolt insertion hole and the female threaded hole.

10. A drive device as claimed in any one of claims 1 to 4, wherein the axial protrusion is integrally formed with the base portion, integrally formed with the disk mounting portion, or provided as a separate member from the base portion and the disk mounting portion.

11. The drive device according to any one of claims 1 to 4, wherein the motor is an in-wheel motor.

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