CN111480284A - Motor unit and in-wheel motor - Google Patents

Abstract

One embodiment of the present invention is a motor unit including: a motor unit having a rotor and a stator; a speed reducer section; a housing having a housing section for housing the motor section and the reducer section; an oil; and a wheel. The rotor has an input shaft, a rotor magnet, and a rotor holder. The rotor holder has a cylindrical portion and a circular plate portion located at one opening of the cylindrical portion. The speed reducer portion has a sun gear, a plurality of planetary gears, and a ring gear. The housing is provided with an oil path for oil circulation. The oil passage includes an input shaft inner radial oil passage. The circular plate portion has: a bottom surface axially opposed to the planetary gear; and a guide portion that protrudes from the bottom surface toward the planetary gear side and guides the oil flowing out of the input shaft to the oil passage toward the planetary gear side.

Description

Motor unit and in-wheel motor

Technical Field

The invention relates to a motor unit and an in-wheel motor. The present application claims priority based on U.S. provisional patent application No. 62/599,870, filed on 12/18/2017, U.S. provisional patent application No. 62/627,287, filed on 2/7/2018, and japanese application No. 2018-070052, filed on 3/30/2018, the contents of which are incorporated herein by reference.

Background

Japanese laid-open patent publication No. 2017-159883 discloses an in-wheel motor as follows: a motor unit for directly driving the wheel is arranged in the wheel.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2017-159883

Disclosure of Invention

Problems to be solved by the invention

The motor unit of the in-wheel motor has a motor portion and a reduction gear portion. Each gear of the speed reducer unit is supported by a bearing member. If the lubricity of the bearing member is reduced, the rotational efficiency of the reduction gear unit may be reduced.

In view of the above-described problems, an object of one embodiment of the present invention is to provide a motor unit and an in-wheel motor that can suppress a reduction in rotational efficiency of a reduction gear unit.

Means for solving the problems

One embodiment of the present invention is a motor unit including: a motor unit having a rotor that rotates around a central axis and an annular stator that is located radially outside the rotor; a speed reducer unit connected to the rotor to reduce rotation of the rotor; a housing having a housing portion that houses the motor portion and the reducer portion; oil stored in the housing; and a wheel connected to the speed reducer unit and transmitting rotation of the rotor through the speed reducer unit. The rotor has: an input shaft extending along the central axis; a rotor magnet radially opposed to the stator; and a rotor holder that holds the input shaft and the rotor magnet. The rotor holder has: a cylindrical portion having a cylindrical shape with the center axis as a center, the rotor magnet being fixed to an outer peripheral surface thereof; and a disc portion located at one opening of the cylindrical portion, the disc portion having the input shaft fixed thereto. The speed reducer unit includes: a sun gear provided on an outer peripheral surface of the input shaft; a plurality of planetary gears disposed radially outward of the sun gear and meshing with the sun gear; a ring gear disposed radially outward of the plurality of pinion gears and meshing with the plurality of pinion gears; a plurality of carrier pins inserted into a gear center hole provided in the planetary gear, and supporting the plurality of planetary gears, respectively; and a wheel carrier that holds the plurality of wheel carrier pins. The housing portion is provided with an oil passage through which the oil circulates. The oil passage includes: an input shaft inner oil passage extending in an axial direction inside the input shaft; and an input shaft inner radial oil passage extending radially outward from the 2 nd oil passage and communicating the 2 nd oil passage with an outside of the input shaft. The circular plate portion has: a bottom surface axially opposed to the planetary gear; and a guide portion that protrudes from the bottom surface toward the planetary gear side and guides the oil flowing out of the input shaft inner diameter direction oil passage toward the planetary gear side.

Effects of the invention

According to one aspect of the present invention, a motor unit and an in-wheel motor are provided that can suppress a reduction in rotational efficiency of a reduction gear unit.

Drawings

FIG. 1 is a cross-sectional view along the X-Z plane of an in-wheel motor of one embodiment.

Fig. 2 is a sectional view of the motor unit of one embodiment along the center axis J.

Fig. 3 is a cross-sectional view perpendicular to the central axis J of the motor unit of one embodiment.

Fig. 4 is a cross-sectional view of an embodiment pump section.

Detailed Description

Hereinafter, an in-wheel motor and a motor unit included in the in-wheel motor according to an embodiment of the present invention will be described with reference to the drawings. In the drawings used in the following description, for the sake of easy understanding of the features, the features may be enlarged for convenience, and the dimensional ratios of the components are not necessarily the same as the actual ones.

An XYZ coordinate system is appropriately shown in each figure. The X-axis direction in each drawing is a direction parallel to the axial direction of the central axis J shown in fig. 1. In the following description, the positive side (+ Z side, one side) in the Z-axis direction is referred to as "upper side", and the negative side (-Z side, the other side) in the Z-axis direction is referred to as "lower side". The upper side and the lower side are directions for explanation only, and do not limit actual positional relationship and directions. Unless otherwise specified, a direction parallel to the central axis J (X-axis direction) is simply referred to as "axial direction" or "vertical direction", a radial direction about the central axis J is simply referred to as "radial direction", and a circumferential direction about the central axis J, that is, a direction around the central axis J is simply referred to as "circumferential direction". In the following description, the term "plan view" refers to a state viewed from the axial direction.

In the following description, the direction in which the central axis J extends is referred to as the axial direction. The center axis J coincides with the width direction of the vehicle. In the following description, the + X side (left side in the drawing) may be referred to as "one axial side", "one side", or "outside in the vehicle width direction", and the-X side (right side in the drawing) may be referred to as "the other axial side", "the other side", or "inside in the vehicle width direction".

In addition, in the present specification, "extend in the axial direction" includes a case of extending in a direction inclined in a range of less than 45 ° with respect to the axial direction, in addition to a case of strictly extending in the axial direction (i.e., a direction parallel to the X axis). In the present specification, "extending along the central axis J" means extending in the axial direction around the central axis J. In addition, in the present specification, "extend in the radial direction" includes a case of extending in a direction inclined in a range of less than 45 ° with respect to the radial direction, in addition to a case of extending strictly in the radial direction, that is, a direction perpendicular to the axial direction.

< in-wheel motor >

Fig. 1 is a cross-sectional view of the in-wheel motor 1 of the present embodiment taken along the central axis J. Fig. 2 is a sectional view of the motor unit 2 of the in-wheel motor 1 along the center axis J. Fig. 3 is a sectional view of the motor unit 2 perpendicular to the central axis J. In addition, FIG. 1 is a sectional view taken along the X-Z plane, and FIG. 2 is a sectional view taken along the X-Y plane. In fig. 1, the motor unit 2 is not shown.

The in-wheel motor 1 of the present embodiment is mounted on a vehicle 9 of a general automobile, for example. However, the in-wheel motor 1 may be mounted on a vehicle such as a motorcycle, a bicycle, and a wheelchair.

As shown in fig. 1, the in-wheel motor 1 of the present embodiment includes a motor unit 2, a hub carrier 50, a hub bearing 60, a brake unit 70, and a wheel 3.

As shown in fig. 2, the motor unit 2 includes a motor unit 10, a reducer unit 20, a bearing member (1 st bearing member) 4, a resolver 5, a pump unit 30, oil O, and a casing 40. That is, the in-wheel motor 1 includes a motor portion 10, a reduction gear portion 20, a bearing member 4, a pump portion 30, oil O, and a casing 40.

The motor unit 10 is an electric motor as a power source of the in-wheel motor 1. The reducer unit 20 has an output shaft 29 that rotates about a central axis J extending in a direction perpendicular to the vertical direction. The speed reducer unit 20 reduces the rotation speed of the motor unit 10 and outputs the rotation speed from the output shaft 29. The output shaft 29 transmits the power of the motor unit 2 to the wheel 3. The case 40 houses the motor section 10, the reducer section 20, the pump section 30, and the oil O.

< hub frame >

As shown in fig. 1, the hub carrier 50 extends along a plane perpendicular to the central axis J. The hub carrier 50 is a disk-shaped member centered on the central axis J. A center hole 50a is provided in the center of the hub carrier 50 in a plan view. The output shaft 29 is inserted through the center hole 50 a. In addition, a hub bearing 60 is located in the central bore 50 a. The hub carrier 50 rotatably supports the output shaft 29 via a hub bearing 60.

The hub carrier 50 has a bearing holding portion 51, an inclined portion 52, a hub carrier flange portion 53, and a pair of coupling portions (knuckles) 54. The bearing holding portion 51, the inclined portion 52, and the hub carrier flange portion 53 are connected to each other to form a circular plate shape. The bearing holding portion 51, the inclined portion 52, and the hub carrier flange portion 53 are arranged in this order from the radially inner side to the radially outer side.

The center hole 50a is provided at the center of the bearing holding portion 51 in a plan view. The bearing holding portion 51 is provided with a screw hole (not shown) to which a fixing screw 64 for fixing the outer race 61 of the hub bearing 60 is fastened. That is, the hub carrier 50 holds the outer ring 61 of the hub bearing 60 at the bearing holding portion 51.

The inclined portion 52 extends radially outward from the outer end of the bearing holding portion 51. The inclined portion 52 is inclined toward the vehicle width direction inner side (the other axial side) as it goes toward the radial outer side. That is, the inclined portion 52 has a conical shape.

The hub carrier flange portion 53 extends radially outward from the inclined portion 52. The hub carrier flange portion 53 is provided with a plurality of screw holes 53a extending in the axial direction. That is, the hub carrier 50 is provided with a plurality of screw holes 53 a. The plurality of screw holes 53a are arranged in the circumferential direction. The plurality of screw holes 53a are fastened to fixing screws 59 for fixing the housing 40 of the motor unit 2 to the hub carrier 50.

The hub carrier flange portion 53 has a 1 st fitting surface 53j facing radially inward at a connecting portion with the inclined portion 52. The 1 st fitting surface 53j extends in the circumferential direction. As described later, the 1 st fitting surface 53j is fitted to the 2 nd fitting surface 43j of the housing 40.

The pair of coupling portions 54 are provided at the upper and lower ends of the hub carrier flange portion 53. The connection portions 54 are connected to a pair of arms 9a provided on the vehicle 9, respectively. That is, the hub carrier 50 is fixed to the vehicle 9 at the coupling portion 54.

< hub bearing >

The hub bearing 60 is located inside the central hole 50a of the hub carrier 50. The hub bearing 60 supports the output shaft 29 rotatably with respect to the hub carrier 50. The hub bearing 60 has an outer ring 61, an inner ring 62, and a plurality of rolling elements 63 between the outer ring 61 and the inner ring 62.

The hub bearing 60 of the present embodiment is a double-row ball bearing. Therefore, the hub bearing 60 has a plurality of rolling elements 63. The plurality of rolling elements 63 are arranged in two rows in the axial direction along the circumferential direction. However, the hub bearing 60 may be a bearing member having another structure.

The hub bearing 60 is detachably fixed to the hub carrier 50. Specifically, the outer race 61 of the hub bearing 60 is detachably fixed to the bearing holding portion 51 of the hub carrier 50 by a fixing screw 64.

The inner race 62 of the hub bearing 60 holds the output shaft 29. An inner spline is provided on an inner peripheral surface 62c of the inner race 62. On the other hand, an outer spline is provided on an outer peripheral surface 29d of the output shaft 29. The inner race 62 is spline-coupled to the output shaft 29. This restricts the circumferential relative rotation of the inner race 62 and the output shaft 29. That is, the inner race 62 rotates together with the output shaft 29.

The inner race 62 of the hub bearing 60 has a 1 st part 62A and a 2 nd part 62B. The 1 st piece 62A and the 2 nd piece 62B are fixed to each other. The 1 st member 62A and the 2 nd member 62B are disposed radially inward of the different rolling elements 63, respectively, and contact the rolling elements 63.

The 1 st member 62A of the inner race 62 has a hub bearing flange portion (wheel mounting portion) 62A extending radially outward. The hub bearing flange portion 62a extends outward (axially one side) in the vehicle width direction with respect to the outer ring 61 of the hub bearing 60. The hub bearing flange 62a is provided with a plurality of screw holes (not shown) arranged in the circumferential direction. The threaded holes are fastened to fixing screws (not shown) that fix the inner race 62, the wheel 3, and the disc rotor 72 of the brake unit 70 to each other. Namely, the wheel 3 and the disc rotor 72 are fixed to the inner ring 62.

< housing >

As shown in fig. 1, the housing 40 is positioned on the vehicle width direction inner side (the other axial side) with respect to the hub carrier 50. The housing 40 is fixed to the vehicle 9 via a hub carrier 50. The case 40 has a housing portion 49 that houses the motor portion 10, the reducer portion 20, and the pump portion 30.

The oil O is stored in the storage portion 49. The oil O is accumulated in the lower region of the housing 49. In the present specification, the "lower region of the housing portion 49" includes a portion located below the center (i.e., the central axis J) of the housing portion 49 in the vertical direction.

The housing 49 is provided with an oil passage 80 through which the oil O circulates in the housing 49. A pump section 30 is provided in a path of the oil passage 80.

As shown in fig. 3, the case 40 includes a tubular member 41, a 1 st base plate 42, a 2 nd base plate 43, a lid 44, and a sealing member 6. The housing portion 49 is a space surrounded by the tubular member 41, the 1 st base plate 42, and the 2 nd base plate 43.

The cylindrical member 41 has a cylindrical shape centered on the central axis J. The cylindrical member 41 extends in the axial direction. The cylindrical member 41 is open on both sides in the axial direction. The motor portion 10 and the reducer portion 20 are housed radially inside the cylindrical member 41.

As shown in fig. 1, the tubular member 41 has a plurality of fixing plate portions 41b protruding radially outward. The fixing plate portion 41b is plate-shaped extending in a direction perpendicular to the central axis J. The plurality of fixing plate portions 41b are arranged in the circumferential direction. Each fixing plate portion 41b is provided with a through hole 41c penetrating in the axial direction. That is, the housing 40 is provided with a plurality of through holes 41 c. A fixing screw 59 for fixing the housing 40 to the hub carrier 50 is inserted through the through hole 41 c. That is, the housing 40 is fixed to the hub carrier 50 at the fixing plate portion 41 b. In addition, the motor unit 2 is fixed to the hub carrier 50 at the housing 40.

In the present embodiment, a case where the plurality of fixing plate portions 41b are provided in the housing 40 is described. However, 1 flange-like fixing plate portion extending in the circumferential direction may be provided in the housing 40. In this case, a plurality of through holes are provided in the flange-shaped fixing plate portion, and fixing screws are inserted into the plurality of fixing holes, respectively.

As shown in fig. 2, the 1 st floor 42 covers an opening on the inside (the other axial side) in the vehicle width direction of the tubular member 41. The 1 st base plate 42 is a circular plate extending in a direction perpendicular to the axial direction with the center axis J as the center. The 1 st base plate 42 is provided with a base plate through hole 45 penetrating in the axial direction. The 1 st floor 42 has a 1 st surface 42a facing the inside in the vehicle width direction and a 2 nd surface 42b facing the outside in the vehicle width direction. The 2 nd surface 42b constitutes a part of the inner wall surface of the housing portion 49.

The 1 st surface 42a of the 1 st base plate 42 is provided with a pump accommodating recess 46 recessed in the axial direction. The bottom plate through hole 45 opens into the pump housing recess 46.

The 1 st base plate 42 is provided with a bearing holding recess 47 recessed in the axial direction on the 2 nd surface 42 b. The bottom plate through hole 45 opens into the bearing holding recess 47. The bearing holding recess 47 holds the bearing member 4, and the bearing member 4 rotatably supports the input shaft 12 of the motor unit 10.

A resolver stator mount 42c protruding in the axial direction is provided on the 2 nd surface 42b of the 1 st base plate 42. That is, the housing 40 has a resolver stator mount portion 42 c. The resolver stator base portion 42c extends in the circumferential direction. The resolver stator 5a is screwed to the resolver stator mount 42 c.

As shown in fig. 1, the 1 st oil passage 81 is provided through the 1 st base plate 42. That is, the 1 st oil passage 81 is provided in the housing 40. The 1 st oil passage 81 extends upward from a lower region of the housing portion 49 of the casing 40. As described above, the oil O is stored in the storage portion 49. The oil O is accumulated in the lower region of the housing 49. The 1 st oil passage 81 leads the oil O stored in the lower region of the housing portion 49 to the suction port 35 of the pump chamber 31. That is, the 1 st oil passage 81 connects the lower region of the housing portion 49 to the suction port 35.

As shown in fig. 2, the lid 44 is fixed to the 1 st surface 42a of the 1 st base plate 42. The cover 44 covers the opening of the pump housing recess 46 of the 1 st base plate 42. The pump chamber 31 of the pump section 30 is configured in a space surrounded by the inner wall surface of the pump housing recess 46 and the lid 44. The pump chamber 31 is connected to the 1 st oil passage 81.

The 2 nd floor 43 covers an opening on the vehicle width direction outer side (one axial side) of the tubular member 41. The 2 nd bottom plate 43 is a circular plate extending in a direction perpendicular to the axial direction with the center axis J as a center. The 2 nd base plate 43 is provided with a through insertion hole 48 penetrating in the axial direction. That is, the housing 40 is provided with a through-insertion hole 48 connecting the inside and outside of the housing portion 49. The output shaft 29 is inserted through the insertion hole 48.

The 2 nd floor panel 43 has a 1 st surface 43a facing the inside in the vehicle width direction and a 2 nd surface 43b facing the outside in the vehicle width direction. The 1 st surface 43a of the 2 nd bottom plate 43 constitutes an inner wall surface of the housing portion 49.

As shown in fig. 1, the 2 nd surface 43b of the 2 nd base plate 43 is axially opposed to the hub carrier 50. The 2 nd surface 43b is provided with a ridge portion 43c projecting in the axial direction. The ridge portion 43c protrudes toward the hub carrier 50. The ridge portion 43c is annular and extends in the circumferential direction around the center axis J.

The raised strip portion 43c has a 2 nd fitting surface 43j facing radially outward. That is, the housing 40 has the 2 nd fitting surface 43 j. The 2 nd fitting surface 43j extends in the circumferential direction. The 2 nd fitting surface 43j is fitted to the 1 st fitting surface 53j provided on the hub carrier 50. Thereby, the housing 40 is positioned in the radial direction with respect to the hub carrier 50.

According to the present embodiment, the motor unit 2 is held from the radially outer side by the hub carrier 50 by fitting the 1 st fitting surface 53j to the 2 nd fitting surface 43 j. Therefore, the strength of fixing the motor unit 2 to the hub carrier 50 can be increased. Further, according to the present embodiment, the motor unit 2 can be easily aligned with respect to the hub carrier 50 by fitting the 1 st fitting surface 53j and the 2 nd fitting surface 43j, and the assembly process can be simplified.

As shown in fig. 2, the seal member 6 is located between the inner peripheral surface of the through insertion hole 48 and the outer peripheral surface of the output shaft 29. The seal member 6 has a circular ring shape in plan view. The seal member 6 is fixed to the inner peripheral surface of the insertion hole 48 of the 2 nd base plate 43. The inner end of the seal member 6 contacts the outer peripheral surface of the output shaft 29. The sealing member 6 is made of an elastic material such as rubber or elastomer resin. The seal member 6 prevents the oil O in the housing portion 49 from leaking to the outside through the insertion hole 48. Further, the seal member 6 suppresses entry of foreign matter into the housing portion 49 from the outside.

< Motor part >

The motor unit 10 includes a rotor 11 and an annular stator 17. The rotor 11 rotates about the center axis J. The stator 17 is located radially outside the rotor 11.

The stator 17 is held on the inner peripheral surface of the cylindrical member 41 of the housing 40. The stator 17 is radially opposed to the rotor magnet 13a of the rotor 11.

The stator 17 includes an annular stator core 19, a coil 18, and an insulating member not shown.

As shown in fig. 3, the stator core 19 includes an annular core back 19a and a plurality of teeth 19b extending radially inward from the core back 19 a. The stator core 19 is formed by laminating laminated steel plates in the axial direction.

The plurality of teeth 19b are arranged in the circumferential direction. The stator 17 of the present embodiment has 72 teeth 19 b. That is, the stator 17 of the present embodiment is 72-slot. The number of slots of the stator 17 is set according to the number of poles of the rotor magnet 13 a.

The coil 18 is wound around the tooth portion 19b via an insulating member. The insulating member (not shown) is made of resin and covers at least a part of the tooth portion 19b of the stator core 19. The insulating member insulates the teeth from the coil. By flowing a current through the coil, a rotating magnetic field is generated in the stator 17. In the present embodiment, the winding method of the coil 18 is not particularly limited, and concentrated winding, distributed winding, or another winding method may be employed.

As shown in fig. 2, the coil 18 has a pair of coil ends 18a and 18b that protrude toward both axial sides with respect to the stator core 19. In the present embodiment, of the pair of coil ends 18a, 18b, the coil end located on the inside in the vehicle width direction (the other side in the axial direction) is referred to as the 1 st coil end 18a, and the coil end located on the outside in the vehicle width direction (the one side in the axial direction) is referred to as the 2 nd coil end 18 b.

The rotor 11 rotates about the center axis J. The rotor 11 includes an input shaft 12, a rotor holder 13, a rotor magnet 13a, and a rotor core 13 b.

The input shaft 12 extends along a central axis J. The input shaft 12 is provided with a sun gear 21 of a reduction gear unit 20 on its outer circumferential surface at a halfway point in the axial direction. The input shaft 12 has a 1 st end portion 12a and a 2 nd end portion 12b located on both sides of the sun gear 21 in the axial direction.

The 1 st end portion 12a of the input shaft 12 is located on the vehicle width direction outer side (one axial side) with respect to the sun gear 21. The 1 st end 12a is housed in a recess (recessed portion) 29a, and the recess (recessed portion) 29a is provided in the output shaft 29.

The 2 nd end portion 12b of the input shaft 12 is located on the inner side (the other side in the axial direction) in the vehicle width direction with respect to the sun gear 21. The 2 nd end portion 12b is rotatably supported by a bearing member 4, and the bearing member 4 is held by the housing 40. The 2 nd end portion 12b is supported by the housing 40 via the bearing member 4.

The input shaft 12 is a hollow shaft centered on the central axis J. In other words, the input shaft 12 is provided with a hollow portion 12c extending in the axial direction and opened at both ends. As described later, the hollow portion 12c functions as a 2 nd oil passage (input shaft inner oil passage) 82, and the 2 nd oil passage is a part of the oil passage 80. That is, the 2 nd oil passage 82 extends in the axial direction inside the input shaft 12.

The input shaft 12 has a shaft flange portion 12d extending radially outward. The input shaft 12 is provided with a 3 rd oil passage (input shaft inner radial oil passage) 83 extending radially outward from the hollow portion 12c (i.e., the 2 nd oil passage 82).

The 3 rd oil passage 83 communicates the 2 nd oil passage 82 with the outside of the input shaft 12. A part of the oil O flowing through the 2 nd oil passage 82 flows into the 3 rd oil passage 83 by a centrifugal force accompanying rotation of the rotor 11. The oil O flowing into the 3 rd oil passage 83 spreads radially outward from the radially outer opening of the 3 rd oil passage 83.

The input shaft 12 is provided with a plurality of (8 in the present embodiment) 3 rd oil passages 83. The 83 rd oil passages 83 are classified into 41 st flow passages 83A and 42 nd flow passages 83B. The axial positions of the 41 st flow paths 83A are uniform. The 41 st flow paths 83A are arranged at equal intervals in the circumferential direction. Similarly, the axial positions of the 42 nd flow paths 83B are uniform. The 42 nd flow paths 83B are arranged at equal intervals in the circumferential direction.

The 1 st flow path 83A is located inward (axially on the other side) in the vehicle width direction from the shaft flange portion 12 d. On the other hand, the 2 nd flow path 83B is located on the vehicle width direction outer side (one axial side) of the shaft flange portion 12 d. That is, the 1 st flow passage 83A is located inward (axially on the other side) in the vehicle width direction with respect to the 2 nd flow passage 83B.

The radially outer opening of the 1 st flow path 83A is radially opposed to a resolver support portion 14c described later. The radially outer opening of the 2 nd flow path 83B is radially opposed to a guide portion 14e described later. The axial position of the radially outer opening of the 2 nd flow passage 83B overlaps with the axial position of the cylindrical portion 15 of the rotor holder 13, which will be described later.

The rotor holder 13 holds the input shaft 12, the rotor core 13b, and the rotor magnet 13a of the input shaft 12. The rotor holder 13 is in the shape of a bottomed cylinder, and is open on the outside in the vehicle width direction (one axial side). The axial position of the opening of the rotor holder 13 overlaps with the axial position of the 2 nd coil end 18 b. That is, the axial position of the opening of the rotor holder 13 overlaps the axial position of one coil end 18b of the pair of coil ends 18a, 18 b.

The rotor holder 13 includes: a disc portion 14 that expands in the radial direction; and a cylindrical portion 15 located at the radially outer end of the circular plate portion 14.

The cylindrical portion 15 is cylindrical with the center axis J as the center. The cylindrical portion 15 extends in the axial direction. A rotor core 13b and a rotor magnet 13a are fixed to the outer peripheral surface of the cylindrical portion 15, and the rotor magnet 13a is fixed via the rotor core 13 b.

A stopper 15d protruding radially inward is provided on the inner peripheral surface of the cylindrical portion 15. The dam portion 15d extends in the circumferential direction. The dam portion 15d is located in the vicinity of the opening on the vehicle width direction outer side (one axial side) of the tubular portion 15.

The circular plate portion 14 is located at an opening on the inside (the other axial side) in the vehicle width direction of the cylindrical portion 15. The disc portion 14 closes the opening on the inside (the other axial side) in the vehicle width direction of the tubular portion 15. The disc portion 14 has a disc shape centered on the central axis J. The disc portion 14 is located between the 1 st flow passage 83A and the 2 nd flow passage 83B in the axial direction. The circular plate portion 14 has a 1 st surface 14a facing the inside in the vehicle width direction and a 2 nd surface (bottom surface) 14b facing the outside in the vehicle width direction. The 2 nd surface 14b is axially opposed to the planetary gear 22.

A fixing hole 14h is provided in the center of the disk portion 14 in a plan view. The fixing hole 14h is fitted to the outer peripheral surface of the input shaft 12. That is, the rotor holder 13 is fixed to the input shaft 12 at the disc portion 14. Further, the shaft flange portion 12d of the input shaft 12 contacts the 2 nd surface 14 b. Thereby, the input shaft 12 and the disc portion 14 are axially aligned.

The rotor holder 13 and the input shaft 12 may be indirectly fixed via another member.

The 1 st surface 14a of the disk portion 14 is provided with a resolver support portion 14c projecting in the axial direction. That is, the disc portion 14 has the resolver support portion 14 c. The resolver support portion 14c protrudes inward in the vehicle width direction (the other side in the axial direction). The resolver support portion 14c extends in the circumferential direction. That is, the resolver support portion 14c is cylindrical with the center axis J as the center. A resolver rotor 5b is fixed to the tip end of the resolver support portion 14 c. The resolver rotor 5b is radially opposed to the resolver stator 5 a. The resolver rotor 5b and the resolver stator 5a constitute a resolver 5. The resolver 5 detects a rotation angle of the rotor 11 with respect to the housing 40.

According to the present embodiment, the resolver support portion 14c protruding in the axial direction and extending in the circumferential direction is provided in the circular plate portion 14, whereby the rigidity of the circular plate portion 14 can be improved. When the disk portion 14 is deformed, the cylindrical portion 15 is displaced, and a gap between the rotor magnet 13a and the stator 17 may be varied. According to the present embodiment, by suppressing the deformation of the disc portion 14, the displacement of the cylindrical portion 15 can be suppressed, and the rotation efficiency of the motor portion 10 can be sufficiently ensured.

A disk portion through hole 14f penetrating in the axial direction is provided at the radially outer end of the disk portion 14. When viewed axially, the radially inner end of the blocking portion 15d overlaps the disk portion through hole 14 f.

The resolver support portion 14c is provided with a through hole 14d extending in the radial direction. The through hole 14d extends so as to be inclined inward in the vehicle width direction (toward the other axial side) as it goes toward the radially outer side. The radially inner opening of the through hole 14d is smoothly continuous with the 1 st surface 14a of the disk portion 14. The radially outer opening of the through hole 14d is radially opposed to the 2 nd coil end 18 b.

The 2 nd surface 14b of the disk portion 14 is provided with a guide portion 14e projecting in the axial direction. That is, the disk portion 14 has a guide portion 14 e. The guide portion 14e protrudes from the 2 nd surface 14b toward the planetary gear 22 side. The guide portion 14e extends annularly in the circumferential direction.

The guide portion 14e is radially opposed to the 2 nd flow path 83B of the 3 rd oil path 83. The surface of the guide portion 14e facing the inside in the radial direction is inclined while being curved toward the outside in the radial direction as facing the front end side of the guide portion 14 e. Therefore, the oil O that has passed along the surface of the guide portion 14e facing the radially inner side reaches the tip of the guide portion 14e, and is scattered toward the planetary gear 22. The guide portion 14e guides the oil O flowing out of the 2 nd flow path 83B of the 3 rd oil path 83 to the planetary gear 22 side.

The rotor core 13b is fixed by pressure contact to the cylindrical portion 15 of the rotor holder 13. The rotor core 13b is formed by laminating laminated steel plates in the axial direction. The rotor core 13b is provided with a plurality of holding holes 13c for holding the rotor magnets 13 a.

As shown in fig. 3, the rotor magnet 13a is radially opposed to the stator 17. The rotor magnet 13a is held by the rotor core 13 b. The rotor magnet 13a is fixed to the outer peripheral surface of the cylindrical portion 15 via the rotor core 13 b.

In the present embodiment, the rotor magnet 13a is constituted by 12 sector magnets 13 aa. That is, the rotor magnet 13a has 12 sector magnets 13 aa. In the present embodiment, the rotor magnet 13a has 12 poles. The rotor magnet 13a may be an annular ring magnet.

The number of poles of the rotor magnet 13a is preferably 10 or more. By setting the number of poles of the rotor magnet 13a to 10 or more, the circumferential dimension of each sector magnet 13aa corresponding to each pole is reduced, and the magnetic force of each sector magnet 13aa is reduced. As a result, the radial dimension of the rotor core 13b can be reduced. This can reduce the weight of the in-wheel motor 1. Further, by making the radial dimension of the rotor core 13b small, the inner diameter of the cylindrical portion 15 can be enlarged. The rotor holder 13 of the present embodiment houses the reducer unit 20 inside the cylindrical portion 15. Therefore, the degree of freedom in the number of teeth of the gears (the sun gear 21, the planet gears 22, and the ring gear 23) constituting the reduction gear unit 20 is increased, and a more preferable reduction gear ratio can be realized. More specifically, the diameter of the planetary gear 22 can be increased to increase the number of teeth of the planetary gear 22, and the reduction ratio of the reduction gear unit 20 can be increased.

In addition, according to the present embodiment, the number of poles of the rotor magnet 13a is set to 10 or more, thereby reducing the magnetic flux density passing through the stator core 19. Therefore, the radial dimension of the stator core 19 can be reduced. Therefore, the motor unit 2 can be downsized and lightened in radial dimension.

< bearing component >

As shown in fig. 2, the bearing member 4 rotatably supports the input shaft 12. In the present embodiment, the bearing member 4 is a ball bearing. The inner race of the bearing member 4 is fixed to the input shaft 12. Further, the outer ring of the bearing member 4 is fixed to a bearing holding recess 47 provided in the housing 40. The bearing member 4 supports the input shaft 12 at a position on the vehicle width direction inner side (the other side in the axial direction) than a connecting portion of the input shaft 12 and the rotor holder 13.

The kind of the bearing member 4 is not limited. For example, a sliding bearing made of a sintered material may be used as the bearing member 4. In this case, the bearing is fixed to either one of the input shaft 12 and the housing 40. In addition, when a material having high wear resistance is used as the housing 40 (more specifically, the 1 st base plate 42), the housing 40 itself may be used as a bearing for the housing 40.

< speed reducer part >

The speed reducer unit 20 is connected to the rotor 11 of the motor unit 10 to reduce the rotation speed of the rotor 11. The speed reducer portion 20 includes a sun gear 21, a plurality of pinion gears 22, a plurality of carrier pins 24, a ring gear 23, and an output shaft 29. The sun gear 21, the planetary gears 22, the ring gear 23, the carrier pins 24, and the output shaft 29 constitute a planetary gear mechanism.

According to the present embodiment, the speed reducer section 20 constitutes a planetary gear mechanism, and therefore the input shaft 12 to which power is input and the output shaft 29 from which power is output can be arranged coaxially. This enables the motor unit 2 to be downsized.

In the present embodiment, the sun gear 21, the pinion gears 22, and the ring gear 23 are helical gears (helical gears). Therefore, when the reducer unit 20 operates, the sun gear 21, the pinion gears 22, and the ring gear 23 are subjected to stress in the axial direction from the gears that mesh with each other. The axial stress to which the sun gear 21 and the ring gear 23 are subjected is in the opposite direction to the axial stress to which the pinion gears 22 are subjected. In the present embodiment, when the vehicle is moving forward, the sun gear 21 and the ring gear 23 receive stress from the pinion gear 22 toward the inside in the vehicle width direction (the other side in the axial direction), and the pinion gear 22 receives stress from the sun gear 21 and the ring gear 23 toward the outside in the vehicle width direction (the one side in the axial direction). When the vehicle is driven backward, each gear receives stress in a direction opposite to the forward direction.

The sun gear 21 is provided on the outer peripheral surface of the input shaft 12 of the rotor 11. That is, the sun gear 21 is fixed to the rotor 11. The sun gear 21 rotates together with the input shaft 12.

In the present embodiment, the sun gear 21 is formed by machining teeth on the outer peripheral surface of the input shaft 12. That is, in the present embodiment, the sun gear 21 and the input shaft 12 are one member. However, the sun gear 21 may be provided on the outer periphery of the input shaft 12, and may be provided on the outer periphery of the input shaft 12 by press-fitting a pinion gear of a separate member into the input shaft 12.

The plurality of planetary gears 22 are disposed radially outward of the sun gear 21. The planetary gear 22 rotates while meshing with the sun gear 21. The planetary gear 22 rotates about the rotation axis Jp. The planetary gear 22 revolves around the sun gear 21. The reducer unit 20 of the present embodiment is provided with 3 planetary gears 22. The 3 planetary gears 22 are arranged at equal intervals in the circumferential direction. In addition, the number of the planetary gears 22 is not limited as long as the plurality of the planetary gears 22 are provided in the speed reducer unit 20.

A gear center hole 22a extending in the axial direction is provided in the center of the planetary gear 22. A carrier pin 24 is inserted into the gear center hole 22 a. The planetary gear 22 rotates about the carrier pin 24.

Generally, a stepped gear is sometimes used as a planetary gear of the planetary gear mechanism. Such a step gear includes two gears arranged in an axial direction and coaxially arranged. The gears of the two stages are fixed with each other. The stepped gear is engaged with the sun gear at the gear of one of the two stages and is engaged with the ring gear at the gear of the other stage.

In contrast, the planetary gear 22 of the present embodiment is not a step gear. The planetary gears 22 are meshed with the sun gear 21 and the ring gear 23 at 1 gear. Therefore, the sun gear 21, the pinion gears 22, and the ring gear 23 are axially overlapped with each other. By adopting such a structure, the axial dimension of the reducer portion 20 can be reduced.

The carrier pins 24 rotatably support the planetary gears 22. The carrier pins 24 revolve around the sun gear 21 together with the planetary gears 22. A bearing member (3 rd bearing member) 22b is disposed between the outer peripheral surface of the carrier pin 24 and the inner peripheral surface of the gear center hole 22a of the planetary gear 22.

In the present embodiment, the bearing member 22b provided in the gear center hole 22a is a so-called roller holder assembly (cage and roller). However, the type of the bearing member 22b is not limited to this, and the bearing member 22b may be a needle bearing, for example.

The carrier pin 24 is provided with a 1 st pin internal oil passage 85 and a plurality of 2 nd pin internal oil passages 86.

The 1 st pin inner oil passage 85 extends axially inside the carrier pin 24. The 1 st pin inner oil passage 85 is open at an end surface of the carrier pin 24 on the vehicle width direction inner side (the other axial side). The 1 st pin internal oil passage 85 is open on the guide portion 14e side of the rotor holder 13. The radial position of the leading end of the guide portion 14e overlaps with the radial position of the 1 st pin internal oil passage 85. Therefore, the transmission oil O is guided along the guide portion 14e into the 1 st pin internal oil passage 85.

The 2 nd pin inner oil passage 86 extends radially outward of the rotation axis Jp from the 1 st pin inner oil passage 85. The 2 nd inner pin oil passage 86 communicates the 1 st inner pin oil passage 85 with the outside of the carrier pin 24. The 2 nd pin internal oil passage 86 axially overlaps with the planetary gear 22. Therefore, the 2 nd pin internal oil passage 86 opens inside the gear center hole 22 a. In the present embodiment, 42 nd pin internal oil passages 86 are provided in the carrier pin 24. The 4 nd pin inner oil passages 86 are arranged at equal intervals in the circumferential direction of the rotation axis Jp.

The output shaft 29 supports the carrier pin 24. The output shaft 29 rotates about the central axis J with the revolution of the planetary gears 22 and the carrier pins 24. The output shaft 29 is rotatably supported by the hub bearing 60.

The output shaft 29 has: a cylindrical output shaft body portion 29A extending in the axial direction about the center axis J; and a carrier (flange portion) 25. The carrier 25 extends radially outward in a flange shape with respect to the output shaft main body portion 29A. In the present embodiment, the output shaft body portion 29A and the carrier 25 are one member. However, the output shaft body portion 29A and the carrier 25 may be separate members coupled to each other.

The wheel carrier 25 has a disc shape centered on the central axis J. The carrier 25 is located at an inner end (the other axial end) of the output shaft body portion 29A in the vehicle width direction. The carrier 25 is located on the vehicle width direction outer side (one axial side) with respect to the plurality of planetary gears 22. An end surface of the carrier 25 facing the inside in the vehicle width direction axially faces the plurality of planetary gears 22.

The carrier 25 is provided with a plurality of (3 in the present embodiment) 1 st pin holding holes (pin holding holes) 25a penetrating in the axial direction. The 1 st pin holding holes 25a are arranged at equal intervals in the circumferential direction. The wheel carrier pin 24 is inserted into the 1 st pin holding hole 25 a. Thereby, the wheel carrier 25 holds the plurality of wheel carrier pins 24 in the 1 st pin holding hole 25 a. The wheel carrier pin 24 is fitted in the 1 st pin holding hole 25 a. Therefore, the wheel carrier pin 24 is fixed to the wheel carrier 25 and does not rotate relative to the wheel carrier 25.

A wheel frame cover 26 is fixed to the wheel frame 25. The wheel frame cover 26 is located on the vehicle width direction inner side (the other axial side) with respect to the wheel frame 25.

The wheel frame cover portion 26 has a circular plate shape centered on the central axis J. The planetary gears 22 are disposed between the carrier 25 and the carrier cover 26 in the axial direction. When viewed from the axial direction, a part of the teeth of the planetary gear 22 protrude radially outward from the carrier 25 and the carrier cover 26.

The carrier cover portion 26 is provided with a plurality of (3 in the present embodiment) 2 nd pin holding holes 26c that penetrate in the axial direction. The wheel carrier pin 24 is inserted into the 2 nd pin holding hole 26 c. The wheel carrier pin 24 is fitted into the 2 nd pin holding hole 26 c. Therefore, both ends of the wheel frame pin 24 are supported by the wheel frame 25 and the wheel frame cover portion 26.

In the axial direction, the 1 st thrust washer 22c is interposed between the carrier 25 and the planetary gear 22 and between the carrier cover portion 26 and the planetary gear 22, respectively. When the reduction gear unit 20 operates, the planet gears 22 are stressed in any direction in the axial direction from the sun gear 21 and the ring gear 23. By providing the 1 st thrust washer 22c, the rotation of the planetary gear 22 can be made smooth, and the wear of the side surface of the planetary gear 22 can be suppressed.

A concave portion 29a is provided on an end surface of the wheel frame 25 facing the inside in the vehicle width direction (the other side in the axial direction). That is, the wheel frame 25 is provided with a recess 29a that opens in the axial direction.

The recess 29a extends along the central axis J. The recess 29a is circular in plan view about the central axis J. The 1 st end 12a of the input shaft 12 is housed in the recess 29 a.

The 2 nd thrust washer 29c is interposed between the bottom surface of the recess 29a and the 1 st end 12a of the input shaft 12. When the input shaft 12 rotates in a predetermined direction, the sun gear 21 receives stress from the planetary gears 22 in one axial direction. Along with this, the 1 st end portion 12a of the input shaft 12 is pressed against the bottom surface of the recess 29 a. According to the present embodiment, by providing the 2 nd thrust washer 29c, the rotation of the input shaft 12 can be made smooth, and the wear of the end surface of the 1 st end portion 12a of the input shaft 12 can be suppressed.

Further, a bearing member (2 nd bearing member) 7 is provided between the inner peripheral surface of the recess 29a and the outer peripheral surface of the 1 st end portion 12 a. That is, the 1 st end portion 12a of the input shaft 12 is supported by the carrier 25 via the bearing member 7. The 2 nd end portion 12b of the input shaft 12 is supported by the housing 40 via the bearing member 4. Therefore, according to the present embodiment, the input shaft 12 can be rotatably supported so as to be held at both ends. This can suppress eccentric rotation of the input shaft 12, and improve the transmission efficiency of the gears in the reduction gear unit 20.

The ring gear 23 is disposed radially outward of the plurality of pinion gears 22. The ring gear 23 surrounds the plurality of pinion gears 22 from the radially outer side. The ring gear 23 meshes with the plurality of pinion gears 22. That is, the planetary gears 22 are engaged with the sun gear 21 on the radially inner side and with the ring gear 23 on the radially outer side.

The ring gear 23 is fixed to the 2 nd base plate 43 of the housing 40. Therefore, when the sun gear 21 rotates, the planetary gears 22 rotate while revolving around the sun gear 21. The carrier 25 rotates about the central axis J with the revolution of the planetary gears 22. The carrier 25 is fixed to the wheel 3 via the output shaft body portion 29A. Thus, the rotation of the wheel carrier 25 is transmitted to the wheel 3.

As shown in the present embodiment, the ring gear 23 is fixed to the housing 40, whereby the sun gear 21 to which the input shaft 12 is connected and the pinion gears 22 to which the carrier 25 is connected are rotated in the same direction. Therefore, wear of the bearing member 7 positioned between the inner peripheral surface of the recessed portion 29a of the carrier 25 and the outer peripheral surface of the input shaft 12 can be suppressed.

In the present embodiment, the sun gear 21, the pinion gears 22, and the ring gear 23 are all housed radially inside the cylindrical portion 15 of the rotor holder 13. More specifically, the end surfaces of the sun gear 21, the planetary gears 22, and the ring gear 23 on the inner side in the vehicle width direction (the other side in the axial direction) are positioned on the outer side in the vehicle width direction (the one side in the axial direction) than the end portions of the cylindrical portion 15 on the inner side in the vehicle width direction (the other side in the axial direction). The end surfaces of the sun gear 21, the planetary gears 22, and the ring gear 23 on the outer side in the vehicle width direction (one axial side) are positioned on the inner side in the vehicle width direction (the other axial side) than the end portion of the cylindrical portion 15 on the outer side in the vehicle width direction (one axial side). Therefore, the axial dimension of the motor unit 2 can be reduced. Further, the in-wheel motor 1 can be thinned in the axial direction.

< Pump part >

The pump section 30 is provided in the center of the 1 st base plate 42. The pump section 30 is disposed on the vehicle width direction inner side (the other side in the axial direction) of the input shaft 12.

Fig. 4 is a sectional view of the pump section 30 in a section perpendicular to the center axis J.

As shown in fig. 4, the pump section 30 includes a pump chamber 31, a coupling member 34, an external gear (inner rotor) 32, an internal gear (outer rotor) 33, a suction port 35, and a pump outlet 36.

As shown in fig. 2, the pump chamber 31 is configured as a space surrounded by an inner wall surface of the pump housing recess 46 provided on the 1 st surface 42a of the 1 st base plate 42 and the lid 44 covering the opening of the pump housing recess 46. An O-ring 44a is provided between the cover 44 and the 1 st surface 42a of the 1 st base plate 42. Thereby, the pump chamber 31 is sealed from the outside. The pump chamber 31 houses an external gear 32 and an internal gear 33. The central axis J passes through the pump chamber 31. The pump chamber 31 has a circular shape when viewed from the axial direction.

The coupling member 34 has a cylindrical shape extending in the axial direction about the central axis J. That is, the coupling member 34 is provided with a hollow portion 34a extending along the central axis J. The connecting member 34 is disposed in the bottom plate through hole 45 of the housing 40.

The coupling member 34 couples the input shaft 12 and the externally toothed gear 32. One end of the connecting member 34 is fitted to the input shaft 12 on the outer peripheral surface. The other end of the connecting member 34 is fitted into the external gear center hole 32a of the external gear 32 on the outer peripheral surface. The hollow portion 34a of the coupling member 34 communicates with the hollow portion 12c provided in the input shaft 12. The hollow portion 34a of the coupling member 34 constitutes a part of the 2 nd oil passage 82.

The external gear 32 is fixed to the 2 nd end portion 12b of the input shaft 12 via a coupling member 34. The externally toothed gear 32 rotates around the center axis J together with the input shaft 12.

Fig. 4 is a sectional view of the pump section 30 in a section perpendicular to the center axis J.

The external gear 32 is housed in the pump chamber 31. The external gear 32 has a plurality of teeth 32b on the outer peripheral surface. The tooth profile of the tooth portion 32b of the external gear 32 is a trochoid tooth profile.

The internal gear 33 surrounds the radially outer side of the external gear 32. The internal gear 33 is an annular gear rotatable about a rotation axis Jt eccentric to the central axis J. The internal gear 33 is housed in the pump chamber 31. The internal gear 33 meshes with the external gear 32. The internal gear 33 has a plurality of teeth 33b on the inner peripheral surface. The tooth profile of the tooth portion 33b of the internal gear 33 is a trochoid tooth profile.

According to the present embodiment, the tooth profile of the tooth portion 32b of the external gear 32 and the tooth profile of the tooth portion 33b of the internal gear 33 are trochoid tooth profiles, and therefore, a trochoid pump can be configured. Therefore, noise generated from the pump section 30 can be reduced, and the pressure and amount of the oil O discharged from the pump section 30 can be easily stabilized.

A 1 st pump internal oil passage 38 and a 2 nd pump internal oil passage 39 are provided in an inner wall surface of the pump chamber 31. The 1 st pump internal oil passage 38 and the 2 nd pump internal oil passage 39 are provided as groove portions formed on the bottom surface of the pump housing recess 46 and the facing surface of the lid portion facing the bottom surface. The 1 st pump inner oil passage 38 and the 2 nd pump inner oil passage 39 extend in an arc shape in the circumferential direction. The 1 st pump inner oil passage 38 and the 2 nd pump inner oil passage 39 are arranged in a circumferential direction. The 1 st pump internal oil passage 38 and the 2 nd pump internal oil passage 39 overlap with the tooth portion 33b of a part of the internal gear 33 when viewed in the axial direction.

The 1 st pump internal oil passage 38 is connected to the 1 st oil passage 81. The 2 nd pump inner oil passage 39 is connected to the hollow portion 34a of the coupling member 34. That is, the 2 nd pump internal oil passage 39 is connected to the 2 nd oil passage 82.

The suction port 35 is provided at a boundary portion between the 1 st pump internal oil passage 38 and the 1 st oil passage 81. The suction port 35 sucks the oil O into the pump chamber 31 from a lower region of the housing portion 49 via the 1 st oil passage 81.

Pump outlet 36 is provided at a boundary portion between pump-2 internal oil passage 39 and pump-2 oil passage 82. The pump outlet 36 discharges oil O from the pump chamber 31. That is, the 2 nd oil passage 82 is connected to the pump outlet 36.

When the input shaft 12 rotates, the externally toothed gear 32 fixed to the input shaft 12 rotates about the center axis J. Thereby, the internal gear 33 meshing with the external gear 32 rotates about the rotation axis Jt. In addition, the portion where the gap between the external gear 32 and the internal gear 33 is widened moves around the center axis J. The oil O sucked into the pump chamber 31 from the suction port 35 is sent to the pump outlet 36 through the gap between the external gear 32 and the internal gear 33. The oil O discharged from the pump outlet 36 flows into the 2 nd oil passage 82. Thus, the pump section 30 is driven via the input shaft 12.

According to the present embodiment, the pump section 30 is driven by the rotation of the input shaft 12, the oil O is sucked from the lower region of the housing section 49, and the oil O circulates in the oil passage 80. Therefore, an external power supply is not required to drive the pump section 30. The oil O is circulated in the housing portion 49 to improve the lubricity of the gears of the reduction gear unit 20, and the motor unit 10 can be cooled by the oil O.

According to the present embodiment, the pump outlet 36 of the pump section 30 is connected to the 2 nd oil passage 82 in the input shaft 12. Since the input shaft 12 rotates about the center axis J, the oil O discharged from the 2 nd oil passage 82 is scattered radially outward by the centrifugal force of the input shaft 12. Therefore, the inside of the 2 nd oil passage 82 becomes a negative pressure, and as a result, the suction of the oil O by the pump section 30 is promoted. Therefore, even when the pump section 30 is downsized, the pump section 30 can be made to have a sufficient suction force. According to the present embodiment, the pump section 30 can be downsized, and the motor unit 2 can be downsized.

< oil passage >

Next, the oil passage 80 through which the oil supply O circulates in the housing portion 49 of the case 40 will be described.

The oil passage 80 includes a 1 st oil passage 81, a 2 nd oil passage 82, a 3 rd oil passage 83, a 1 st pin inner oil passage 85, and a 2 nd pin inner oil passage 86.

When the in-wheel motor 1 is stopped, the oil O is accumulated in the lower region of the housing portion 49. As shown in fig. 1, the upper limit of the liquid level of the oil O in the lower region of the housing portion 49 is preferably lower than the lower end portion of the rotor 11. This can prevent the oil O from acting as resistance to the rotation of the rotor 11. The 1 st oil passage 81 is located below the lower limit of the liquid level of the oil O with respect to the opening of the housing portion 49.

When the in-wheel motor 1 is driven, the pump section 30 is also driven as the input shaft 12 rotates. When the pump section 30 is driven, the oil O accumulated in the lower region of the housing section 49 moves from the suction port 35 into the pump chamber 31 through the 1 st oil passage 81. The oil O in the pump chamber 31 moves from the pump outlet 36 to the 2 nd oil passage 82.

A part of the oil O in the 2 nd oil passage 82 flows into the 3 rd oil passage 83 by a centrifugal force based on the rotation of the input shaft 12. Further, a part of the oil O in the 2 nd oil passage 82 reaches an outer end (one axial side) in the vehicle width direction of the 2 nd oil passage 82.

The oil O flowing into the 3 rd oil passage 83 moves radially outward in the 3 rd oil passage 83 by a centrifugal force. The oil O reaching the radially outer side of the 3 rd oil passage 83 scatters radially outward from the outer peripheral surface of the input shaft 12.

According to the present embodiment, by providing the 3 rd oil passage 83 in the input shaft 12, the oil O can be scattered from the 3 rd oil passage 83 into the housing portion 49 by the centrifugal force of the input shaft 12. This can improve the lubricity of each part in the housing 49, and can cool the motor unit 10 with the oil O.

The axial position of the 1 st flow path 83A of the 3 rd oil passage 83 overlaps with the axial position of the resolver support portion 14 c. The oil O scattered radially outward from the 1 st flow path 83A reaches the resolver support portion 14 c. Then, the first coil end 18a is reached through the through hole 14d of the resolver support portion 14c, and the first coil end 18a is cooled.

Further, a part of the oil O diffused from the opening of the 1 st flow path 83A is supplied to the bearing member 4. The oil O supplied to the bearing member 4 promotes lubrication of the bearing member 4, and suppresses wear of the bearing member 4.

The axial position of the 2 nd flow path 83B of the 3 rd oil path 83 overlaps with the axial position of the guide portion 14 e. The oil O scattered radially outward from the 2 nd flow path 83B reaches the guide portion 14 e. The oil O that has reached the guide portion 14e is transferred along the surface of the guide portion 14e facing the radially inner side and splashes toward the planetary gear 22 side.

Part of the oil O scattered toward the planetary gear 22 by the guide portion 14e is supplied to the tooth surface of the planetary gear 22. This can improve the transmission efficiency among the sun gear 21, the pinion gears 22, and the ring gear 23. Further, wear of the sun gear 21, the pinion gears 22, and the ring gear 23 can be suppressed.

Part of the oil O scattered to the planetary gear 22 side by the guide portion 14e is introduced into the 1 st pin internal oil passage 85 provided in the carrier pin 24. A part of the oil O flowing into the 1 st pin inner oil passage 85 is guided to the outer peripheral surface of the carrier pin 24 through the 2 nd pin inner oil passage 86. A bearing member 22b is disposed between the outer peripheral surface of the carrier pin 24 and the inner peripheral surface of the gear center hole 22 a. According to the present embodiment, the lubricity of the bearing member 22b can be improved by supplying the oil O to the bearing member 22 b. The oil O guided to the outer peripheral surface of the carrier pin 24 flows along the end surface of the planetary gear 22 and is supplied to the 1 st thrust washer 22 c. According to the present embodiment, the lubricity of the 1 st thrust washer 22c can be improved. The oil O flows radially outward and is supplied to the tooth surfaces of the pinion gears 22 and the ring gear 23.

In the present embodiment, the guide portion 14e extends annularly in the circumferential direction. Therefore, the oil O scattered from the 2 nd flow path 83B of the 3 rd oil path 83 can be captured as much as possible and guided to the 1 st in-pin oil path 85.

The guide portion 14e does not need to extend annularly in the circumferential direction. For example, the disk portion 14 may have a plurality of guide portions arranged discretely in the circumferential direction.

Part of the oil O scattered from the guide portion 14e reaches the inner circumferential surface of the cylindrical portion 15 of the rotor holder 13.

The 2 nd oil passage 82 opens at the 1 st end portion 12a of the input shaft 12. Therefore, the oil O of the 2 nd oil passage 82 flows out from the 2 nd oil passage 82 at the 1 st end portion 12a of the input shaft 12. The 1 st end portion 12a of the input shaft 12 is housed in a recess 29a provided in the output shaft 29. Therefore, the 2 nd oil passage 82 opens inside the recess 29 a. The oil O flows into the recess 29a from the 2 nd oil passage 82.

The oil O flowing into the recess 29a is supplied to the 2 nd thrust washer 29c and the bearing member 7 housed in the recess 29 a. This enables smooth rotation of the input shaft 12.

Further, a part of the oil O flowing into the recess 29a moves in the axial direction and flows out from the opening of the recess 29 a. Part of the oil O flowing out from the opening of the recess 29a flows radially outward and flows into the gap between the carrier 25 and the planetary gear 22. The oil O flowing into the gap between the carrier 25 and the planetary gear 22 improves the lubricity of the 2 nd thrust washer 29c interposed between the carrier 25 and the planetary gear 22.

The cylindrical portion 15 of the rotor holder 13 is located radially outward of the planetary gears 22. Therefore, a part of the oil O scattered radially outward of the planetary gear 22 via the 1 st pin oil passage 85 is captured by the inner circumferential surface of the cylindrical portion 15.

A stopper 15d is provided on the inner peripheral surface of the cylindrical portion 15. The dam portion 15d damps the oil O that is to flow out from the opening on the vehicle width direction outer side (one axial side) of the cylindrical portion 15 at the inner peripheral surface of the cylindrical portion 15. The disk portion 14 is provided with a disk portion through hole 14f extending in the axial direction. The disk portion through hole 14f allows the oil O retained on the inner peripheral surface of the cylindrical portion 15 by being retained by the retaining portion 15d to pass therethrough. The oil O having passed through the disk portion through hole 14f scatters radially outward and reaches the 1 st coil end 18a, thereby cooling the 1 st coil end 18 a. The oil O that has passed over the dam portion 15d is scattered radially outward from the opening of the rotor holder 13. The oil O scattered from the opening of the rotor holder 13 cools the 2 nd coil end 18 b. According to the present embodiment, by providing the dam portion 15d and the disk portion through hole 14f in the rotor holder 13, the amount of oil O scattering from the rotor holder 13 to the 1 st coil end 18a can be made close to the amount of oil O scattering to the 2 nd coil end 18 b. This enables the 1 st coil end 18a and the 2 nd coil end 18b to be cooled in a balanced manner.

The oil reaching the 1 st coil end 18a and the 2 nd coil end 18b moves downward by gravity. Thereby, the oil O is collected again by the lower region of the housing portion 49.

< brake part >

As shown in fig. 1, the brake section 70 includes a brake caliper (not shown) and a disc rotor 72. The brake unit 70 brakes the rotation of the wheel 3. A disc rotor 72 is fixed to the wheel 3 and rotates with the wheel. The caliper sandwiches the disc rotor from both sides in the axial direction, and brakes the rotation of the wheel 3 via the disc rotor 72.

< wheel >)

The wheel 3 has a rim portion 3a, a disk portion 3b, and a fixing portion 3 c.

The wheel 3 is connected to an output shaft 29 of the reduction gear unit 20. The rotation of the rotor 11 of the motor unit 10 is transmitted to the wheel 3 via the speed reducer unit 20. The wheel 3 holds a tire, not shown, at the rim portion 3 a. The wheels 3 transmit power to a road surface via tires.

The rim portion 3a has a cylindrical shape centered on the central axis J. The motor unit 2, the hub bracket 50, the hub bearing 60, and the brake section 70 are disposed radially inward of the rim section 3 a. More specifically, the entire hub carrier 50 and the entire hub bearing 60 are disposed radially inward of the rim portion 3 a. That is, the entire hub carrier 50 and the entire hub bearing 60 are located inside the wheel 3.

An end portion of the motor unit 2 on the vehicle width direction outer side (one axial side) is positioned on the vehicle width direction outer side (one axial side) with respect to an end portion of the rim portion 3a on the vehicle width direction inner side (the other axial side). Therefore, at least a part of the motor unit 2 is disposed radially inward of the rim portion 3 a. I.e. at least a part of the motor unit 2 is located inside the wheel 3.

According to the present embodiment, by housing at least a part of the motor unit 2, the hub carrier 50, and the hub bearing 60 inside the wheel 3, it is possible to suppress these components from protruding largely inward in the vehicle width direction, and to improve the degree of freedom in designing the vehicle.

An end portion of the motor unit 2 on the inside in the vehicle width direction (the other side in the axial direction) is positioned on the inside in the vehicle width direction (the other side in the axial direction) with respect to an end portion of the rim portion 3a on the inside in the vehicle width direction (the other side in the axial direction). Therefore, at least a part of the motor unit 2 is disposed outside the rim portion 3 a. That is, at least a part of the motor unit 2 is exposed from the wheel 3. When the in-wheel motor 1 is driven, the vehicle with the in-wheel motor travels. According to the present embodiment, the motor unit 2 is exposed from the wheel 3, and therefore, when the vehicle travels, a flow of air (wind) opposing the housing 40 is generated outside the housing 40, and the housing 40 is cooled. Accordingly, the stator core 19 held by the case 40 and the oil O in the case 40 are cooled.

The disk portion 3b is located at an opening on the vehicle width direction outer side (one axial side) of the rim portion 3 a. The disk portion 3b extends radially inward from an outer end (one axial side) of the rim portion 3a in the vehicle width direction. A fixing portion 3c is provided at an end portion of the disk portion 3b on the inner side in the radial direction. That is, the disk portion 3b connects the rim portion 3a and the fixing portion 3 c.

The fixed portion 3c is located at the center of the wheel 3 in plan view. The fixing portion 3c has an annular plate shape centered on the central axis J. The fixed portion 3c is located on the axially opposite side of the motor unit 2 with respect to the hub carrier 50 and the disc rotor 72. The fixing portion 3c is provided with a plurality of through holes (not shown) extending in the axial direction. The plurality of through holes are arranged in the circumferential direction.

A fixing screw (not shown) is inserted through a through hole (not shown) of the fixing portion 3c, and the fixing screw fixes the fixing portion 3c, the disc rotor 72, and the inner ring 62 of the hub bearing 60 to each other. That is, the wheel 3 is fixed to the inner race 62 of the hub bearing 60 and the disc rotor 72 at the fixing portion 3 c. Further, the inner race of the hub bearing is fixed to the output shaft 29 in the circumferential direction. Therefore, the fixing portion 3c is fixed to the output shaft 29. In addition, the wheel 3 is fixed to the output shaft 29.

While the embodiments of the present invention have been described above, the respective configurations and combinations thereof in the embodiments are examples, and additions, omissions, substitutions, and other modifications of the configurations can be made without departing from the scope of the present invention. The present invention is not limited to the embodiments.

For example, a case in which a speed reducer of a gear mechanism is used as the speed reducer portion of the above embodiment is exemplified, but a speed reducer of a roller mechanism may be used.

In the motor unit described above, an example is given in which an output shaft that outputs power of the motor unit is connected to a planetary gear. However, the output shaft may be connected to the ring gear.

For example, the motor unit of the above embodiment is not limited to a vehicle, and can be widely used for various devices having wheels, such as a robot, such as an unmanned carrier, an agricultural implement, or a cleaning robot.

Description of the reference symbols

1: an in-wheel motor; 2: a motor unit; 3: a wheel; 9: a vehicle; 10: a motor section; 11: a rotor; 12: an input shaft; 13: a rotor holder; 13 a: a rotor magnet; 14: a circular plate portion; 14 b: the 2 nd face (bottom face); 14d, 41 c: a through hole; 14 e: a guide section; 14 f: a circular plate part through hole; 15: a cylindrical portion; 17: a stator; 20: a speed reducer section; 21: a sun gear; 22: a planetary gear; 22 a: a gear central bore; 23: a ring gear; 24: a wheel carrier pin; 25: a wheel carrier; 30: a pump section; 31: a pump chamber; 32: an external gear; 33: an internal gear; 35: a suction inlet; 36: an outlet of the pump; 40: a housing; 49: a storage section; 50 a: a central bore; 80: an oil path; 81: the 1 st oil path; 82: a 2 nd oil passage; 82: the 2 nd oil path (the input shaft inner oil path); 83: a 3 rd oil path; 83: a 3 rd oil passage (input shaft inner radial oil passage); 85: the 1 st pin inner oil way; 86: the 2 nd pin internal oil way; j: a central axis; o: and (3) oil.

Claims (8)

1. A motor unit having:

a motor unit having a rotor that rotates around a central axis and an annular stator that is located radially outside the rotor;

a speed reducer unit connected to the rotor to reduce rotation of the rotor;

a housing having a housing portion that houses the motor portion and the reducer portion;

oil stored in the housing; and

a wheel connected to the speed reducer unit and transmitting rotation of the rotor through the speed reducer unit,

the rotor has:

an input shaft extending along the central axis;

a rotor magnet radially opposed to the stator; and

a rotor holder that holds the input shaft and the rotor magnet,

the rotor holder has:

a cylindrical portion having a cylindrical shape with the center axis as a center, the rotor magnet being fixed to an outer peripheral surface thereof; and

a disc portion located at one opening of the cylindrical portion and to which the input shaft is fixed,

the speed reducer unit includes:

a sun gear provided on an outer peripheral surface of the input shaft;

a plurality of planetary gears disposed radially outward of the sun gear and meshing with the sun gear;

a ring gear disposed radially outward of the plurality of pinion gears and meshing with the plurality of pinion gears;

a plurality of carrier pins inserted into a gear center hole provided in the planetary gear, and supporting the plurality of planetary gears, respectively; and

a wheel carrier that holds a plurality of the wheel carrier pins,

the housing portion is provided with an oil passage through which the oil circulates,

the oil passage includes:

an input shaft inner oil passage extending in an axial direction inside the input shaft; and

an input shaft inner radial oil passage extending radially outward from the input shaft inner oil passage to communicate the input shaft inner oil passage with an outside of the input shaft,

the circular plate portion has:

a bottom surface axially opposed to the planetary gear; and

and a guide portion that protrudes from the bottom surface toward the planetary gear side and guides the oil flowing out from the inner diameter of the input shaft to the oil passage toward the planetary gear side.

2. The motor unit according to claim 1,

the oil passage includes:

a 1 st pin internal oil passage that extends in the axial direction inside the carrier pin and opens on the guide portion side; and

a 2 nd pin internal oil passage that communicates the 1 st pin internal oil passage with an outside of the carrier pin,

the radial position of the leading end of the guide portion overlaps with the radial position of the oil passage in the 1 st pin.

3. The motor unit according to claim 1 or 2, wherein,

the guide portion extends annularly in the circumferential direction.

4. The motor unit according to any one of claims 1 to 3,

the disk portion is provided with a disk portion through hole that penetrates in the axial direction.

5. The motor unit according to any one of claims 1 to 4,

at least a part of the planetary gear is housed inside the cylindrical portion in the radial direction.

6. The motor unit according to claim 5,

the entire planetary gear is housed radially inside the cylindrical portion.

7. The motor unit according to any one of claims 1 to 6,

the motor unit includes a pump section located in the housing section and driven via the rotor,

the pump section includes:

an external gear fixed to an end of the input shaft;

an internal gear that surrounds a radially outer side of the external gear and meshes with the external gear;

a pump chamber provided in the housing and housing the internal gear and the external gear;

a suction port that sucks the oil into the pump chamber; and

a pump outlet to discharge the oil from the pump chamber,

the oil passage includes a 1 st oil passage connecting a lower region of the housing portion with the suction port.

8. An in-wheel motor having:

the motor unit of any one of claims 1 to 7; and

and a wheel connected to the speed reducer unit and transmitting rotation of the rotor through the speed reducer unit.

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