CN111788764A - In-wheel motor driving device - Google Patents

Abstract

A motor housing (25) of an in-wheel motor drive device (10) is provided with: a first support section (29b) which is disposed above an axis (M) extending in the vehicle width direction and supports the stator (24) by surface contact with the outer peripheral surface of the stator in an axial region from the center to the end in the axial direction of the stator; a second support portion (29c) which is arranged below an axis (M) extending along the vehicle width direction and supports the stator by surface contact with the outer peripheral surface of the stator in an axial direction region from the center to the end of the stator in the axial direction; and third support portions (29d) which are disposed in the vehicle front or rear direction across the axis (M) when viewed from the first or second support portions, and which support the stator by surface contact with the outer peripheral surface of the stator in the axial direction region from the axial direction center portion to the end portion of the stator, wherein the first to third support portions (29) are provided at intervals in the circumferential direction.

Description

In-wheel motor driving device

Technical Field

The present invention relates to a motor drive device for driving a wheel, and to a structure for fixing a stator of a motor unit to a housing of the motor unit.

Background

A motor that drives a wheel as in patent document 1 is known. Patent document 1 relates to a cylindrical stator coaxially housed in a cylindrical housing, and an annular positioning plate is fixed to one end surface of a stator core. The positioning plate has an abutting portion protruding radially outward than the stator core at a circumferential position of three points around the center. The contact portion is in line contact with an inner peripheral surface of the housing. The other end surface of the stator core is fixed to the end surface of the housing by a bolt.

According to the description of patent document 1, the abutting portion of the positioning plate directly abuts against the inner peripheral surface of the housing, thereby suppressing misalignment between the rotor and the stator of the motor. Further, noise and vibration of the motor are suppressed.

[ Prior Art document ]

[ patent document ]

[ patent document 1 ] Japanese patent No. 4811114

Disclosure of Invention

[ SUMMARY OF THE INVENTION ]

[ problem to be solved by the invention ]

In-wheel motors in which a motor for driving a wheel is disposed inside the wheel are known. Since the irregularities of the road surface are input to the in-wheel motor as an external force in the vertical direction, the in-wheel motor is used in an environment where it is more likely to receive an external force and vibration than the in-vehicle motor mounted on the vehicle body. When the motor of patent document 1 is used as an in-wheel motor, the contact portion is in line contact, and therefore the weight of the stator cannot be sufficiently supported, and an external force in the vertical direction may act on the housing to cause elastic deformation or vertical displacement of the stator, which is not preferable.

That is, since the stator is a heavy object, if only one end of the stator in the axial direction is bolted to the other housing and the contact portion at the three circumferential points is supported at the other end of the stator in the axial direction as in patent document 1, a gap is formed between the intermediate region of the stator excluding both ends and the housing, and the stator may vibrate in the vertical direction.

The present invention has been made in view of the above circumstances, and an object thereof is to avoid causing undesirable vibration of a stator, which is a heavy object, in the vertical direction in a structure for supporting the stator of the in-wheel motor.

[ MEANS FOR solving PROBLEMS ] A method for solving the problems

In order to achieve the object, an in-wheel motor drive device according to the present invention includes: a hub bearing unit for rotatably supporting a hub ring coupled to a wheel; and a motor unit that drives the hub ring, the motor unit including: a motor rotating shaft extending in the vehicle width direction; a rotor coupled to a motor rotation shaft; a cylindrical stator facing the rotor with a gap therebetween; and a motor housing that surrounds an outer periphery of the stator, the motor housing including: a first support portion which is arranged above an axis of a motor rotating shaft extending along a vehicle width direction and supports the stator by surface contact with an outer peripheral surface of the stator; a second support portion that is disposed below an axis of the motor rotating shaft extending in the vehicle width direction, and that supports the stator by being in surface contact with an outer peripheral surface of the stator; and a third support portion that is disposed in front of or behind the vehicle across an axis of the motor rotation shaft extending in the vehicle width direction when viewed from the first support portion or the second support portion, and that supports the stator by surface contact with an outer peripheral surface of the stator, wherein the first support portion, the second support portion, and the third support portion are disposed at intervals in the circumferential direction.

According to the present invention, the motor case is supported by the region continuously facing the center portion to the end portion in the axial direction of the stator, and therefore vibration of the heavy stator can be prevented. In particular, when the external force input from the road surface is mainly in the vertical direction, the stator as the weight is supported by the upper first support portion and the lower first support portion as in the present invention, and thus the vertical vibration of the stator can be prevented. The upper side of the axis of the motor rotation shaft means the upper side of the electric vehicle when the in-wheel motor drive device is mounted on the electric vehicle. The lower side than the axis of the motor rotation shaft means the lower side of the electric vehicle when the in-wheel motor drive device is mounted on the electric vehicle. The outer peripheral surface of the stator is, for example, the outer peripheral surface of the stator core. According to the present invention, since the first to third support portions support the stator from three sides in the circumferential direction, the center of the stator is positioned, and the center of the stator can be prevented from being displaced away from the center. Between the one support portion and the other support portion, the inner peripheral surface of the motor case is separated from the outer peripheral surface of the stator.

The first to third support portions of the present invention may be wall-shaped or block-shaped. As an aspect of the present invention, the motor case further includes a wall portion that branches from any one of the first to third support portions and extends. According to the above aspect, since the wall portion is provided upright on the support portion of the motor case, the rigidity of the support portion of the motor case is increased by the wall portion, and the stator is supported by the motor case so as not to be relatively displaceable. The orientation of the wall portion is not particularly limited. The wall portion provided upright on the support portion may be curved or may be flat. Also, the wall portion may be substantially parallel to the axis of the motor rotation shaft, or may be substantially perpendicular. Alternatively, the wall portion may not be provided upright on the support portion of the motor case.

As a preferred aspect of the present invention, the motor housing further includes: an outer wall formed at a position outside the inner wall with any one of the first to third support portions as the inner wall; and a connecting wall connecting the inner wall and the outer wall, wherein the connecting wall is arranged at two positions with a space, and forms a box body together with the inner wall and the outer wall. According to the above aspect, the rigidity of the support portion is increased by the case, and the heavy stator is supported by the support portion of the motor case so as not to be relatively displaced. The inner wall is, for example, a cylindrical wall and the outer wall is, for example, a flat wall.

In a more preferred aspect of the present invention, the internal space of the motor case is an oil atmosphere, the case including the motor case support portion is disposed below the motor rotation shaft, the outer wall of the case is disposed below the inner wall and protrudes in the axial direction of the motor portion from the inner wall, a lubricant oil receiving port is formed between the outer wall and an end edge in the axial direction of the inner wall, and the lubricant oil flows into the lubricant oil receiving port from the internal space. According to the above aspect, the lubricant oil for lubricating or cooling the inside of the motor portion can be recovered from the lubricant oil receiving port and guided to the oil reservoir portion or the like.

The shape and size of the outer wall are not particularly limited. As one aspect of the present invention, the outer wall of the housing is an inclined wall disposed so as to be apart from the inner wall on one side in the axial direction and to be close to the inner wall on the other side in the axial direction of the motor rotating shaft. Alternatively, the inner wall and the outer wall may be arranged in parallel or substantially in parallel. The shape of the outer wall is not particularly limited. The outer wall may be smaller than the inner wall, may be the same size, or may be larger than the inner wall.

[ Effect of the invention ]

As described above, according to the present invention, in the structure in which the housing of the in-wheel motor drive device supports the heavy stator, the support rigidity is improved. Thus, even if an external force in the vertical direction due to the unevenness of the road surface acts on the stator, it is possible to prevent the stator from being undesirably displaced.

Drawings

Fig. 1 is a schematic view showing the inside of an in-wheel motor drive device according to an embodiment of the present invention.

Fig. 2 is an expanded sectional view showing this embodiment.

Fig. 3 is a longitudinal sectional view schematically showing the motor portion of the embodiment.

Fig. 4 is a longitudinal sectional view schematically showing a lower portion of the motor housing of this embodiment.

Fig. 5 is a view showing the in-wheel motor drive device and its peripheral structure of the embodiment as viewed from the rear of the vehicle.

Fig. 6 is an expanded sectional view specifically showing the in-wheel motor drive device of the embodiment.

Fig. 7 is a partially exploded perspective view of the in-wheel motor drive device according to this embodiment.

Fig. 8 is a diagram showing the inside of the motor unit according to the embodiment.

Fig. 9 is a longitudinal sectional view showing the motor unit of the embodiment.

Fig. 10 is a longitudinal sectional view showing the motor unit of the embodiment.

Fig. 11 is a view showing the motor rotary shaft and the rotor taken out of the embodiment.

Fig. 12 is a transverse cross-sectional view showing a motor rotation shaft, a rotor, and a stator.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Fig. 1 is a schematic view showing the inside of an in-wheel motor drive device according to an embodiment of the present invention, in which a motor housing cover is removed to show the positions of a stator and the like. In fig. 1, components such as the rotor are not shown for the sake of easy understanding of the present invention. In fig. 1, the right side of the drawing indicates the front of the vehicle, the left side of the drawing indicates the rear of the vehicle, the upper side of the drawing indicates the upper side of the vehicle, and the lower side of the drawing indicates the lower side of the vehicle. In fig. 1, the vehicle width direction outer side (outside side) is viewed from the vehicle width direction inner side (inside side).

Fig. 2 is an expanded cross-sectional view showing the embodiment, and the cross-section shown in fig. 2 is an expanded plane connecting a plane including the axis M and the axis N shown in fig. 1 and a plane including the axis N and the axis O in this order. In fig. 2, the left side of the drawing indicates the outside (outside) in the vehicle width direction, and the right side of the drawing indicates the inside (inside) in the vehicle width direction. Fig. 6 is an expanded sectional view showing the in-wheel motor driving apparatus of fig. 2 in detail.

As shown in fig. 2, the in-wheel motor drive device 10 includes a hub bearing portion 11 provided at the center of a wheel, not shown, a motor portion 21 that drives the wheel, and a speed reduction portion 31 that reduces the speed of rotation of the motor portion and then transmits the rotation to the hub bearing portion 11. The motor unit 21 and the speed reducer unit 31 are disposed offset from the axis O of the hub bearing unit 11. The axis O extends in the vehicle width direction and coincides with the axle. The position in the direction of the axis O is such that the hub bearing portion 11 is disposed on one side (outer side) in the axial direction of the in-wheel motor drive device 10, the motor portion 21 is disposed on the other side (inner side) in the axial direction of the in-wheel motor drive device 10, the speed reduction portion 31 is disposed on one side in the axial direction of the motor portion 21, and the position of the speed reduction portion 31 in the axial direction overlaps with the position of the hub bearing portion in the axial direction.

The in-wheel motor drive device 10 is a vehicle motor drive device that drives a wheel of an electric vehicle. The in-wheel motor drive device 10 is coupled to a vehicle body, not shown. The in-wheel motor driving device 10 can drive the electric vehicle at a speed of 0-180 km/h.

As shown in fig. 2, the hub bearing portion 11 is a rotating inner ring/fixed outer ring, and includes an inner ring 12 serving as a moving ring (hub ring) coupled to a traveling wheel of a wheel (not shown), an outer ring 13 serving as a stationary ring coaxially disposed on the outer diameter side of the inner ring 12, and a plurality of rolling elements 14 disposed in an annular space between the inner ring 12 and the outer ring 13. The rotation center of the inner race 12 coincides with an axis O passing through the center of the hub bearing portion 11.

On the outer peripheral surface of the outer ring 13, a plurality of outer ring protrusions 13f are provided upright at circumferentially different positions. Through holes are formed in the outer ring projecting portions 13f projecting in the outer diameter direction. Each through hole extends parallel to the axis O, and the bolt 15 is inserted through the through hole from one side in the direction of the axis O. The shaft portion of each bolt 15 is screwed into a female screw hole formed in the bracket member 61. Thereby, the outer ring 13 is coupled and fixed to the holder member 61.

The front portion 38f of the main body case 38 is adjacently disposed on the other side of the holder member 61 in the axis O direction. The holder member 61 is also provided with a plurality of female screw holes. A plurality of through holes are provided at circumferentially different positions in the front surface portion 38f of the main body case 38, and these through holes are connected to the female screw holes of the bracket member. The female screw hole of the holder member 61 and the through hole of the outer ring protrusion 13f extend parallel to the axis O, and the bolt 62 is inserted through the other side in the direction of the axis O. The shaft portion of each bolt 62 is screwed into a female screw hole formed in the bracket member 61. Thereby, the main body case 38 is coupled and fixed to the bracket member 61.

The main body case 38 is a case that forms the outer contour of the speed reducer 31. The front portion 38f is a case wall portion of the main body case 38 that covers one end of the deceleration portion 31 in the axis O direction. The outer race 13 passes through the front portion 38 f.

The inner ring 12 is a cylindrical body longer than the outer ring 13, and passes through a center hole of the outer ring 13. A coupling portion 12f is formed at one end portion in the axis O direction of the inner ring 12 protruding from the outer ring 13 to the outside of the in-wheel motor drive device 10. The coupling portion 12f is a flange and constitutes a coupling portion for coupling coaxially with a brake disk and a wheel, not shown. The inner ring 12 is a hub ring, and is coupled to a traveling wheel of the wheel through a coupling portion 12f to rotate integrally with the wheel.

Double rows of rolling elements 14 are arranged in an annular space between the inner ring 12 and the outer ring 13. The outer peripheral surface of the center portion in the axis O direction of the inner ring 12 constitutes an inner raceway surface of the plurality of rolling elements 14 arranged in the first row. An inner raceway ring 12r is fitted to the outer periphery of the other end portion of the inner ring 12 in the axis O direction. The outer peripheral surface of the inner raceway ring 12r forms an inner raceway surface of the plurality of rolling elements 14 arranged in the second row. The inner circumferential surface of one end portion of the outer ring 13 in the axis O direction constitutes an outer raceway surface of the rolling elements 14 in the first row. The inner circumferential surface of the other end portion of the outer ring 13 in the axis O direction constitutes an outer raceway surface of the rolling elements 14 in the second row. A seal 16 is interposed in an annular space between the inner race 12 and the outer race 13. The seal 16 seals both ends of the annular space, and prevents the entry of dust and foreign matter. The output shaft 37 of the speed reducer 31 is inserted into the center hole at the other end of the inner race 12 in the axis O direction and spline-fitted.

The motor unit 21 includes a motor rotating shaft 22, a rotor 23, a stator 24, and a motor housing 25, which are sequentially arranged from the axis M of the motor unit 21 to the outer diameter side. The motor unit 21 is a radial gap motor of an inner rotor or an outer stator type, but may be of another type. For example, although not shown, the motor unit 21 may be an axial gap motor. The motor case 25 surrounds the outer periphery of the stator 24. One end of the motor case 25 in the direction of the axis M is coupled to the back surface portion 38b of the main body case 38. The other end of the motor housing 25 in the axis M direction is sealed by a plate-shaped motor housing cover 25 v. The back surface portion 38b is a case wall portion of the main body case 38 that covers the other end of the speed reducer 31 in the axis M direction (the axis O direction).

The main body case 38 and the motor case 25 constitute a case that is an outer shell of the in-wheel motor drive device 10. In the following description, a part of the main body case 38 and the motor case 25 is also simply referred to as a case.

The stator 24 includes a cylindrical stator core 24b and a coil 24c wound around the stator core 24 b. The stator core 24b is formed by laminating annular steel plates in the direction of the axis M.

Both ends of the motor rotary shaft 22 are rotatably supported by the rear surface portion 38b of the main body case 38 and the motor case cover 25v of the motor unit 21 via rolling bearings 27, 28. A rotation angle sensor 52 is provided at the other end portion of the motor rotary shaft 22 in the axis M direction. The rotation angle sensor 52 is disposed on the inner side of the rolling bearing 28 in the axis M direction, and is attached to the center portion of the motor housing cover 25 v.

An axis M, which is a rotation center of the motor rotary shaft 22 and the rotor 23, extends in parallel with the axis O of the hub bearing portion 11. That is, the motor unit 21 is offset from the axis O of the hub bearing unit 11. For example, as shown in fig. 1, the axis M of the motor unit is offset from the axis O in the vehicle front-rear direction, and specifically, is disposed in the vehicle front direction with respect to the axis O. The axis O extends in the vehicle width direction, and therefore the axis M and the axis N parallel to the axis O also extend in the vehicle width direction. That is, these axes M, N, O extend generally in a horizontal direction.

As shown in fig. 1, the motor housing 25 is formed in a substantially cylindrical shape with a predetermined circumferential position projecting outward in the radial direction. The motor case 25 of the present embodiment includes: a box-shaped power line terminal box 26b projecting upward; a box-shaped signal line terminal box 26c projecting toward the rear of the vehicle; and a semi-cylindrical projecting portion 26d projecting toward the vehicle front. Specifically, power line terminal box 26b is disposed above axis M. The signal line terminal box 26c is disposed below the axis M and behind the vehicle. The protruding portion 26d is disposed below the axis M and in front of the vehicle.

The portions of the motor case 25 between the three circumferentially separated projections constitute first to third wall-shaped support portions 29. The inner wall surfaces of the first to third support portions 29 are recessed cylindrical surfaces centered on the axis M. When the first to third support portions 29 are distinguished, suffixes b, c, and d are given. The first support portion 29b and the third support portion 29d are provided above the axis M. The second support portion 29c is provided below the axis M. The first to third support portions 29 of the present embodiment are cylindrical walls. Alternatively, the first to third support portions 29 may be flat walls, and the inner wall surfaces thereof may be formed as recessed cylindrical surfaces.

The third support portion 29d is disposed rearward of the vehicle across the axis M when viewed from the first support portion 29 b. The second support portion 29c is disposed directly below the axis M. The first to third support portions 29 are provided at intervals in the circumferential direction. The first to third support portions 29 are preferably arranged so as to include three points spaced at 120 ° intervals in the circumferential direction.

As a modification not shown, the first support portion may be disposed directly above the axis M, the second and third support portions may be disposed below the axis M, and the second and third support portions may be disposed with a space therebetween in the vehicle longitudinal direction.

Referring to fig. 2, power wire terminal box 26b accommodates three coil terminals 41 that are drawn out from an end (coil end) of stator 24 in the direction of axis M. Three power wires (power wires 43 in fig. 7 described later) extending from the outside of the in-wheel motor drive device 10 are drawn into the power wire terminal box 26b, and the end portions of the power wires are connected to the coil terminals 41 via a connector structure (not shown).

Incidentally, the third support portion 29d includes a projecting wall 29 d' projecting into the power line terminal box 26 b. In other words, case side wall 26f of power line terminal box 26b branches from third support portion 29d and extends upward. Case side wall 26f is a wall that extends substantially in the vertical direction, and is integrally connected to projecting wall 29 d' at the lower edge and is integrally connected to case top wall 26e of power line terminal box 26b at the upper edge. The housing top wall 26e is a substantially horizontal wall.

In the signal terminal box 26c, end portions (not shown) of lead wires extending from a plurality of sensors such as a rotation angle sensor 52 (fig. 2), a temperature sensor (not shown), and other sensors provided in the in-wheel motor drive device 10 are collected. A signal wire (not shown) extending from the outside of the in-wheel motor drive device 10 is led into the signal wire terminal box 26c, and an end of the signal wire is connected to an end of the lead wire via a connector structure (not shown).

Fig. 1 shows an end face of the stator 24 that appears by removing the motor housing cover 25v from the motor housing 25. In order to avoid complication of the drawing, in fig. 1, an end face of the stator 24 is simplified by hatching, and a part of a structure for fixing the rotor, the motor rotation shaft, and the stator 24 to the back surface portion 38b is omitted.

The inner circumferential surfaces of the first support portion 29b, the second support portion 29c, and the third support portion 29d are in surface contact with the outer circumferential surface of the stator 24. In this way, the first to third support portions 29 at three locations spaced apart in the circumferential direction support the outer circumferential surface of the stator 24 from the outer diameter side, whereby the stator 24 is positioned coaxially with the axis M. The fitting of the stator 24 and the motor case 25 may be press-fit or may be a fitting not involving press-fitting.

A groove-shaped notch 25g is formed in the inner wall surface of the motor case 25 so as to be adjacent to the first support portion 29 b. Also, a groove-shaped notch 24g is similarly formed in the outer peripheral surface of the stator 24. The notches 24g and 25g extend parallel to the axis M and have circular-arc cross sections. The notches 24g and 25g are set at the same circumferential position, and a round bar-shaped rotation preventing pin is inserted between the notches 24g and 25 g. In the present embodiment, similarly, a groove-like cutout is formed in the third support portion 29d, and a corresponding groove-like cutout is provided in the outer peripheral surface of the stator 24, and the rotation prevention pin 30 is similarly inserted. That is, the anti-rotation pins 30 are provided at a plurality of positions in the circumferential direction of the stator 24. By using the rotation preventing pin 30 as an elastic member such as rubber or a spring, transmission of vibration of the stator 24 to the motor housing 25 can be reduced.

A projection 24d projecting outward in the outer diameter direction is formed on the outer peripheral surface of the stator 24. The rib 24d is a part of the stator core 24b (fig. 2), and extends from one end to the other end of the stator 24 in the direction of the axis M. In the present embodiment, the ribs 24d are provided at a plurality of positions with intervals in the circumferential direction. Each of the ribs 24d is formed with a through hole 24h extending parallel to the axis M. The stator 24 is attached to and fixed to a housing of the in-wheel motor drive device by inserting a fixing mechanism described later into the through hole 24 h. The respective protrusions 24d are accommodated in the power line terminal box 26b, the signal line terminal box 26c, and the protruding portion 26d, respectively. A gap G exists between the inner wall surface of the protruding portion 26d and the ridge 24 d. Since the other ribs 24d are disposed in the internal spaces of the power line terminal box 26b and the signal line terminal box 26c, the ribs 24d are spaced from the inner wall surfaces of these terminal boxes. The rib 24d, particularly, one end portion of the rib 24d in the axis M direction corresponds to a portion of the stator 24 that is fixed to the rear surface portion 38b side.

The plurality of through holes 24h are provided at intervals in the circumferential direction. Specifically, the through holes 24h are disposed above and below the axis M, respectively. The through-holes 24h are disposed at positions in front of and behind the vehicle, respectively, at a position below the axis M. Alternatively, as a modification not shown, the through holes 24h may be disposed at positions in front of and behind the vehicle, among positions above the axis M. The same applies to the ridge 24 d. In the present embodiment, the ridges 24d and the through holes 24h are arranged at three positions at equal intervals in the circumferential direction.

The holder member 61 is extended upward and downward from the box-shaped signal line terminal box 26c, and has a plurality of through holes 63 in the extended portion. The bracket member 61 is coupled to a suspension device (not shown) by inserting a coupling tool such as a bolt 62 (fig. 2) into the through hole 63. Thus, the in-wheel motor drive device 10 is connected to the vehicle body of the electric vehicle via the suspension device, and can bounce/rebound in the vertical direction by the suspension device. The in-wheel motor drive apparatus 10 can also perform steering in the left-right direction by the suspension device.

As shown in fig. 2, the decelerating section 31 includes: an input shaft 32s coaxially coupled to the motor rotating shaft 22 of the motor unit 21; an input gear 32 coaxially provided on an outer peripheral surface of the input shaft 32 s; a plurality of intermediate gears 33, 35; an intermediate shaft 34 coupled to the center of the intermediate gears 33 and 35; an output shaft 37 coaxially coupled to the inner ring 12 of the hub bearing portion 11; an output gear 36 coaxially provided on an outer peripheral surface of the output shaft 37; and a main body case 38 accommodating the plurality of gears and the rotating shaft. The main body case 38 is also called a speed reduction unit case because it is an outer shell of the speed reduction unit 31.

The input gear 32 is an externally toothed helical gear. The input shaft 32s has a hollow structure, and one end portion in the axial direction of the motor rotary shaft 22 is inserted into the hollow input shaft 32s and spline-fitted (including serration fitting, the same applies hereinafter) so as not to be relatively rotatable. The input shaft 32s is rotatably supported at both ends of the input gear 32 by a front portion 38f and a rear portion 38b of the main body case 38 via rolling bearings 32m and 32 n.

An axis N which is a rotation center of the intermediate shaft 34 of the speed reducer 31 extends parallel to the axis O. Both ends of the intermediate shaft 34 are rotatably supported by the front portion 38f and the rear portion 38b of the main body case 38 via bearings 34m and 34 n. The first intermediate gear 33 and the second intermediate gear 35 are provided in the central portion of the intermediate shaft 34 coaxially with the axis N of the intermediate shaft 34. The first intermediate gear 33 and the second intermediate gear 35 are externally toothed helical gears, and the diameter of the first intermediate gear 33 is larger than that of the second intermediate gear 35. The first intermediate gear 33 having a large diameter is disposed on the other side in the axis N direction than the second intermediate gear 35, and meshes with the input gear 32 having a small diameter. The second intermediate gear 35 having a small diameter is disposed on one side of the first intermediate gear 33 in the axis N direction, and meshes with the output gear 36 having a large diameter.

As shown in fig. 1, the axis N of the intermediate shaft 34 is disposed above the axes O and M. The axis N of the intermediate shaft 34 is disposed further to the vehicle front side than the axis O and further to the vehicle rear side than the axis M. The speed reducer 31 is a three-axis parallel-shaft gear reducer having axes O, N, M arranged at intervals in the vehicle front-rear direction and extending parallel to each other.

Returning to fig. 2, the output gear 36 is a helical gear with external teeth, and is coaxially provided at the center of the output shaft 37. The output shaft 37 extends along an axis O. One end of the output shaft 37 in the axis O direction is inserted into the center hole of the inner race 12 and fitted so as not to rotate relatively. The fitting is spline fitting or serration fitting. The other end portion of the output shaft 37 in the axis O direction is rotatably supported by a rear surface portion 38b of the main body case 38 via a rolling bearing 37 n.

An annular projection 36c is formed on one end surface of the output gear 36 in the axis O direction. The annular projection 36c is a wall extending in the circumferential direction around the axis O. An annular step 38g is formed in the front portion 38f of the main body case 38 on the outer diameter side of the annular projection 36 c. The annular step 38g surrounds the entire circumference of the annular projection 36 c. A rolling bearing 37m is provided between the inner diameter side annular projection 36c and the outer diameter side annular step 38 g. Thereby, the central portion of the output shaft 37 in the axis O direction is rotatably supported by the front surface portion 38f of the main body case 38 via the rolling bearing 37 m.

The reduction unit 31 reduces the rotation of the input shaft 32s and transmits the reduced rotation to the output shaft 37 by the engagement of the small-diameter drive gear and the large-diameter driven gear, that is, the engagement of the input gear 32 and the first intermediate gear 33 and the engagement of the second intermediate gear 35 and the output gear 36. The rotation elements of the speed reduction unit 31 from the input shaft 32s to the output shaft 37 constitute a drive transmission path for transmitting the rotation of the motor unit 21 to the inner race 12.

The main body case 38 includes a cylindrical portion, and a plate-like front portion 38f and a back portion 38b that cover both ends of the cylindrical portion. The cylindrical portion covers the internal components of the speed reducer portion 31 so as to surround the axes O, N, M extending parallel to each other. The plate-shaped front portion 38f covers the internal components of the speed reducer section 31 from one side in the axial direction. The plate-like back surface portion 38b covers the internal components of the speed reducer section 31 from the other side in the axial direction. The rear surface portion 38b of the main body case 38 is also a partition wall that is coupled to the motor case 25 and partitions an internal space of the speed reducer section 31 and an internal space of the motor section 21. The motor case 25 is supported by the main body case 38, and protrudes from the main body case 38 to the other side in the axial direction.

The main body case 38 divides the internal space of the speed reducer 31, and accommodates all the rotating elements (the rotating shaft and the gears) of the speed reducer 31 in the internal space. As shown in fig. 1, an oil reservoir 39 is provided at the lower portion of the main body case 38. The oil reservoir 39 is disposed at a position lower than the motor unit 21. The oil reservoir 39 of the main body case 38, which occupies the lower portion of the internal space, stores lubricating oil for lubricating and cooling the inside of the motor unit 21 and the inside of the speed reduction unit 31.

The input shaft 32s, the intermediate shaft 34, and the output shaft 37 are supported by the rolling bearing described above. The rolling bearings 32m, 34m, 37m, 32n, 34n, and 37n are radial bearings.

The annular convex portion 36c, the output shaft 37, and one end surface of the output gear 36 in the axis O direction constitute an annular concave portion that is concave in the axis O direction. The annular recess portion accommodates the other end portion of the inner ring 12 in the axis O direction and the other end portion of the inner raceway ring 12r in the axis O direction. In this way, the inner ring 12 and the rolling bearing 37m are arranged so as to overlap with each other at the position in the direction of the axis O, whereby the dimension in the direction of the axis of the in-wheel motor drive device 10 can be reduced.

When electric power is supplied to the coil terminal 41 from the outside of the in-wheel motor drive device 10, the rotor 23 of the motor unit 21 rotates, and the rotation is output from the motor rotation shaft 22 to the speed reduction unit 31. The speed reduction unit 31 reduces the speed of rotation input from the motor unit 21 to the input shaft 32s, and outputs the rotation from the output shaft 37 to the hub bearing unit 11. The inner ring 12 of the hub bearing portion 11 rotates at the same rotational speed as the output shaft 37, and drives a wheel, not shown, attached and fixed to the inner ring 12.

Next, the above-described structure for fixing the stator of the motor unit to the housing of the in-wheel motor drive device will be described in addition.

Fig. 3 is a longitudinal sectional view schematically showing a state where the motor portion is cut by a plane shown in III-III of fig. 1 and the section is viewed in the direction of an arrow, and shows a section different from the section of the motor portion shown in fig. 2. In fig. 3, a motor housing cover 25v covering the other end of the stator 24 is indicated by a two-dot chain line. The abutting surface 25d of the motor housing cover 25v and the abutting surface 25d of the motor housing 25 abutting each other are flat surfaces. The abutting surface 25d is disposed at the other end of the motor unit 21 in the axis M direction. In the present embodiment, the position of the abutting surface 25d in the direction of the axis M overlaps the position of the stator 24 in the direction of the axis M, but the abutting surface 25d may be disposed on the other side of the stator 24 in the direction of the axis M. The motor housing cover 25v is fixed to the motor housing 25 by a fixing mechanism such as a bolt not shown. The motor housing cover 25v is separated from the stator 24 toward the other side in the direction of the axis M.

The inner space of the motor case 25 and the inner space of the main body case 38 are divided by a circular plate portion 38 e. The circular plate portion 38e is a part of the rear surface portion 38b, and has a center hole through which the motor rotation shaft 22 passes. A bearing 27 is mounted in the center hole.

A housing base 38c is formed at an outer diameter portion of the circular plate portion 38 e. The case base 38c protrudes from the circular plate portion 38e toward the other side in the axis M direction. The projecting end of the case base 38c is provided as a flat surface perpendicular to the axis M. A female screw hole 38d is formed in the housing base 38c to point to the other side in the direction of the axis M. Case base 38c is disposed at the same circumferential position as power line terminal box 26b (fig. 1). The other case base 38c is disposed at the same circumferential position as the signal line terminal box 26c (fig. 1) and the protruding portion 26d (fig. 1). The case bases 38c of the present embodiment are arranged at equal intervals in the circumferential direction at 120 °. As shown in fig. 3, the housing base 38c is formed integrally with one end of the motor housing 25 in the direction of the axis M. One end of the coil 24c in the axis M direction is arranged on the inner diameter side of the case base 38 c. Thereby, the position of the one end portion of the coil 24c in the axis M direction overlaps the position of the case base 38c in the axis M direction.

The bolt 51 as the fixing means passes through the through hole 24h of the stator 24 from the other side in the direction of the axis M. When the tip end portion of the bolt 51 is screwed into the female screw hole 38d of the housing base 38c and screwed into the head portion of the bolt 51, the head portion of the bolt 51 abuts on the other end of the ridge 24d in the axis M direction and presses the stator 24 against the housing base 38 c. Thereby, the stator 24 is fixed to the housing base 38c and immovable in the axis M direction.

Incidentally, the motor housing 25 is partially formed as a double wall. For example, the lower portion of the motor housing 25 includes an inner wall and an outer wall. The inner wall is the second support portion 29 c. The outer wall 25j is flat and is provided with a space outward from the second support portion 29c (inner wall). The outer wall 25j is an inclined wall in which one side in the direction of the axis M is lowered and the other side in the direction of the axis M is raised. Therefore, one end of the outer wall 25j in the direction of the axis M is disposed away from the second support portion 29c (inner wall), and the other end of the outer wall 25j in the direction of the axis M is disposed close to the second support portion 29c (inner wall).

Further, the second support portion 29c (inner wall) and one circumferential edge of the outer wall 25j are coupled to each other via the connecting wall 25c around the axis M. The second support portion 29c (inner wall) and the other circumferential edge of the outer wall 25j are also coupled to each other via the connecting wall 25 c. Thereby, the lower portion of the motor case 25 is formed in a box shape.

As shown in fig. 3, the second support portion 29c is continuous from one end of the stator core 24b in the axis M direction to the center, and supports the stator 24 over the above-described region. The second support portion 29c is in surface contact with the stator 24 in the circumferential direction (fig. 2). Similarly, the first support portion 29b (fig. 1) and the third support portion 29d (fig. 1) are in surface contact with the stator 24 via a surface extending in the axis M direction and the circumferential direction. Thus, the stator 24 is reliably supported by the motor case 25. Therefore, even if an external force acts on the heavy stator 24, the stator 24 is not easily displaced relative to the motor case 25.

The space between the lower outer wall 25j and the upper second support portion 29c (inner wall) is connected to the oil reservoir 39 on one side in the direction of the axis M. The outer wall 25j protrudes further toward the other side in the direction of the axis M than the wall-shaped second support portion 29 c. Therefore, the lubricant oil receiving port 53 is formed between the axial end edge of the second support portion 29c and the outer wall 25 j. The lubricant oil receiving port 53 communicates the internal space of the motor case 25 under the oil atmosphere with the oil reservoir 39. The lubricant oil around the stator 24 flows down, passes through the lubricant oil receiving port 53 from the internal space of the motor case 25, and then passes through the space between the outer wall 25j and the second support portion 29c (inner wall) to flow toward the oil reservoir 39.

Power line terminal box 26b is formed from one end to the other end in the axis M direction of motor case 25, adjacent to case base 38 c. Although not shown, the same applies to the signal line terminal box 26c and the protruding portion 26 d. Therefore, the bead 24d is separated from the power line terminal box 26b over the entire length of the bead 24d as shown in fig. 3. The signal line terminal box 26c and the projection 26d are also separated from the ridge 24d in the same manner.

As shown in fig. 1, the abutting surface 25d extends in a band shape and surrounds the stator 24. Specifically, the abutting surface 25d includes a proximal portion 25g extending in an arc shape along the outer peripheral surface of the stator 24. Abutting surface 25d constitutes the outline of power line terminal box 26b, the outline of signal line terminal box 26c, and the outline of protrusion 26 d. The contour portion of the abutting surface 25d is a bulge portion 25f projecting radially outward so as to be spaced apart from the outer peripheral surface of the stator 24.

As shown in fig. 1, the circumferential position of one through hole 24h is arranged to overlap the circumferential position of the protruding portion 26d with respect to the axis M of the motor portion 21. The circumferential position where the other through hole 24h is disposed overlaps the circumferential position of the power wire terminal box 26 b. The circumferential position where the further through hole 24h is disposed overlaps the circumferential position of the signal line terminal box 26 c. That is, the bolts 51 (fig. 3) as the stator fixing means inserted through the through holes 24h are arranged so as to overlap the circumferential positions of the respective bulging portions 25 f.

Fig. 4 is a longitudinal sectional view schematically showing a lower portion of the motor case of the present embodiment, which is taken along a plane indicated by IV-IV in fig. 1 and viewed in the direction of an arrow. In fig. 4, components other than the housing are not shown. A part of the motor case 25 constitutes a double wall having the wall-shaped support portion 29 as an inner wall and the outer wall 25j as an outer wall. The edge of the support portion 29 serving as a cylindrical wall is integrally coupled to the edge of the outer wall 25 j. The integral joint portion is the other end in the direction of the axis M, and forms an abutting surface 25 d.

The in-wheel motor drive device 10 of the present embodiment includes: a hub bearing unit 11 that rotatably supports an inner ring 12 (hub wheel) coupled to a wheel; and a motor unit 21 for driving the inner race 12. The motor unit 21 includes: a motor rotary shaft 22 extending in the vehicle width direction; a rotor 23 coupled to the motor rotation shaft 22; a cylindrical stator 24 facing the rotor 23 with a gap therebetween; and a motor case 25 surrounding the outer periphery of the stator 24. The motor housing 25 includes: a first support portion 29b that is disposed above the motor rotation shaft 22 and that supports the stator 24 by surface contact with the outer peripheral surface of the stator 24 in an area of the stator 24 in the direction of the axis M from the center portion to the end portion in the direction of the axis M; a second support portion 29c that is disposed below the motor rotation shaft 22 and that supports the stator 24 by surface contact with the outer peripheral surface of the stator 24 in an area of the stator 24 in the direction of the axis M from the center to the end in the direction of the axis M; and a third support portion 29d that is disposed rearward of the vehicle across the motor rotary shaft 22 when viewed from the first and second support portions 29, and that supports the stator 24 by surface contact with the outer peripheral surface of the stator 24 in an area of the stator 24 in the direction of the axis M from the center to the end in the direction of the axis M. The first to third support portions 29 are provided at intervals in the circumferential direction. The stator 24 is reliably supported by the motor case 25 by such surface contact. Therefore, even if an external force acts on the heavy stator 24, the stator 24 is not easily displaced relative to the motor case 25.

The motor housing 25 of the present embodiment further includes a housing side wall 26f branched and extended from the third support portion 29 d. The rigidity of the third support portion 29d is increased by the case side wall 26f, and the stator 24 is supported by the motor case 25 so as not to be relatively displaced.

Further, the motor case 25 of the present embodiment further includes: an outer wall 25j formed at a position outside the inner wall with the wall-shaped second support portion 29c as the inner wall; and a connecting wall 25c connecting the second support portion 29c (inner wall) and the outer wall 25 j. The connecting wall 25c is disposed at two positions with a space in the circumferential direction of the motor unit 21, and constitutes a case together with the second support portion 29c (inner wall) and the outer wall 25 j. The rigidity of the second support portion 29c is increased by the case, and the stator 24 is supported by the motor case 25 so as not to be relatively displaced.

The internal space of the motor case 25 of the present embodiment is an oil atmosphere. The casing formed by the two connecting walls 25c, the second support portion 29c (inner wall), and the outer wall 25j is disposed below the motor rotation shaft 22 and is connected to the oil reservoir 39. The outer wall 25j is disposed below the second support portion 29c (inner wall) and protrudes in the axis M direction of the motor unit 21 from the inner wall, and a lubricant oil receiving opening 53 is formed between the outer wall 25j and an end edge of the inner wall in the axis M direction. The lubricant oil flows into the lubricant oil receiving port 53 from the internal space of the motor case 25, and the lubricant oil is guided to the oil reservoir 39. As a result, the lubricant oil for lubricating or cooling the interior of the motor unit 21 can be recovered from the lubricant oil receiving port 53 and can be made to flow to the oil reservoir 39.

The outer wall 25j of the present embodiment is an inclined wall that is disposed away from the second support portion 29c (inner wall) on one side and closer to the second support portion 29c (inner wall) on the other side in the direction of the axis M of the motor rotary shaft 22.

Fig. 5 is a view showing the in-wheel motor drive device and its peripheral structure of the present embodiment as viewed from the rear of the vehicle. The in-wheel motor drive device 10 disposed in the hollow area of the traveling wheel W is coupled to a vehicle body (not shown) via a suspension device 100. The suspension device 100 is, for example, a strut-type suspension device, and includes a lower arm 101 extending in the vehicle width direction and a damper 102 disposed above the lower arm 101 and extending in the vertical direction.

The lower arm 101 is rotatably connected to the vehicle-body side cross member at vehicle-width-direction inner ends 101b and 101c via a cylindrical rubber sleeve, not shown, and is swingable in the vertical direction with the vehicle-width-direction inner ends 101b and 101c as base ends and the vehicle-width-direction outer end 101d as a free end. The vehicle width direction outer end 101d is connected to a lower portion of the in-wheel motor drive device 10 via a ball joint 103. The in-wheel motor drive device 10 is configured to be freely changeable in orientation with respect to the lower arm 101.

The damper 102 extends in the vertical direction along the axis of a coil spring, not shown, and constitutes a strut of a strut-type suspension device together with the coil spring. The damper 102 and the coil spring are also referred to as a shock absorber. The lower end of the damper 102 is coupled to the upper portion of the in-wheel motor drive unit 10. The upper end of the damper 102, not shown, is connected to a vehicle-body side cross member.

Next, the structure of the details provided in the in-wheel motor drive device of the present embodiment will be described.

Fig. 7 is a perspective view showing a state in which the in-wheel motor drive device of the embodiment is partially disassembled and viewed from above, in which a motor housing cover (a motor housing cover 25v shown in fig. 6) is removed to show the inside of the motor unit, and a cover member (a cover member 50 shown in fig. 9) described later is removed to show the inside of the terminal box. The substantially cylindrical motor case 25 is disposed so as to be parallel to the vehicle width direction. The terminal box 26b is attached to protrude in the outer diameter direction. In particular, in the present embodiment, the terminal box 26b protrudes upward from the motor unit 21. When the cover member covering the upper opening 55 of the terminal box 26b is removed, the inside of the terminal box, particularly the power wire terminal 43b, is exposed from the upper opening 55. A plurality of coil lead wires 42 are arranged at the coil end. A coil terminal 41 is press-fitted to the tip of each coil lead wire 42.

Fig. 8 is a view showing the interior of the motor unit according to the embodiment, in which a motor case cover covering the inside of the motor unit in the vehicle width direction is removed to observe a coil end inside the motor unit. Fig. 9 is a longitudinal sectional view showing the motor unit according to the embodiment, and shows a state in which the motor unit and the terminal box are cut by a-a in fig. 8 and the section is viewed in the direction of the arrow. Fig. 10 is a longitudinal sectional view showing the motor unit according to the embodiment, and shows a state in which the motor unit and the terminal box are cut by B-B of fig. 8 and the section is viewed in the direction of the arrow.

As shown in fig. 9, a partition wall 44 that partitions the internal space of the terminal box 26b into a box space T and a motor space L is provided upright inside the terminal box 26 b. Both the tank space T and the motor space L are closed spaces, but lubricating oil is present in the motor space L, whereas lubricating oil is not present in the tank space T. Partition wall 44 is penetrated by terminal block 45 disposed inside terminal box 26 b. The terminal block 45 is made of resin and extends parallel to the axis M.

A conductive member 46 is provided inside the terminal block 45. The conductive member 46 is, for example, a round bar made of copper. A resin terminal block 45 is molded around the outer periphery of the conductive member 46, and the terminal block 45 is attached to the surface of the conductive member 46. Therefore, the terminal block 45 and the conductive member 46 are handled as a single unit.

The resin terminal block 45 surrounds the conductive member 46 and insulates the conductive member 46 from the surroundings. The conductive member 46 also extends parallel to the axis M. Both ends of the conductive member 46 are exposed without being covered with the terminal block 45, and female screws 46b and 46c are formed. A metal bolt 47 penetrating the coil terminal 41 is screwed into the female screw 46c on the inside in the vehicle width direction. A metal bolt 48, which penetrates the power wire terminal 43b crimped to the tip end of the power wire 43, is screwed into the female screw 46b on the outside in the vehicle width direction. Thus, the power wires 43, which are cables routed outside the in-wheel motor drive device 10, and the coil lead wires 42, which are routed inside the in-wheel motor drive device 10, are electrically connected by the conductive members 46.

A flange 45f is integrally formed at a central portion in the longitudinal direction of the terminal block 45. The flange 45f is formed with a through hole (not shown) through which the bolt 49 passes. The shaft portion of the bolt 49 is screwed into a screw hole (not shown) formed in the partition wall 44 and having a bottom. Thereby, terminal block 45 is fixed inside terminal box 26 b.

According to the present embodiment, the power line terminal 43b and the coil terminal 41 are fixed to both ends of the conductive member 46 in the longitudinal direction, and the terminal block 45 surrounds the outside of both ends of the conductive member 46. Thereby, the creeping distance between the adjacent conductive members 46, 46 among the plurality of conductive members 46 can be ensured. By ensuring the creepage distance, electrical accidents such as short circuits are not likely to occur, and safety is improved.

The terminal box 26b of the present embodiment is disposed above the in-wheel motor drive device 10. Since terminal box 26b is disposed above in-wheel motor drive device 10, terminal box 26b is brought close to the vehicle body, and therefore the length of power line 43 extending from the vehicle body to terminal box 26b can be shortened, and the cost can be reduced.

Further, by disposing the terminal box 26b above the motor portion 21, the possibility that the lubricating oil in the motor space L enters the box space T is reduced.

As shown in fig. 8, the plurality of coil terminals 41 are arranged obliquely as viewed along the axis M of the motor unit 21. Specifically, the coil terminals 41 are arranged at intervals in the vehicle front-rear direction and extend upward, and are arranged in a wild-goose-type manner so that the coil terminals 41 arranged at the forefront of the vehicle are highest and the coil terminals arranged at the rear of the vehicle are sequentially low. The coil terminal 41 disposed at the forefront of the vehicle is disposed directly above the axis M, and the remaining coil terminals 41 are disposed at the vehicle rear side with respect to the axis M.

In this way, since the coil terminals 41 and 41 … of the present embodiment are arranged obliquely, the terminal box 26b is compact so as to be accommodated in a narrow hollow area of the travel wheel W. Further, as shown in fig. 8, since the metal bolts 47 do not overlap each other when viewed in the direction of the axis M, a space for contact and work to the metal bolts 47 can be secured, and the work of attaching and detaching the metal bolts 47 can be facilitated.

Referring to fig. 10, an annular seal 54 is disposed on the outer periphery of the terminal block 45. The seal 54 seals an annular gap formed between the through hole of the partition wall 44 and the terminal block 45. This prevents the lubricating oil present in the motor space L from entering the tank space T.

Referring to fig. 10, a portion of the back portion 38b divides the terminal box 26 b. A bottomed hole 26g is formed in the wall surface of the rear surface portion 38 b. A projection 45b extends from an end of the terminal block 45. The projection 45b is fitted into the bottomed hole 26 g.

The terminal block 45 shown in fig. 10 is supported at two points by the projection 45b and the flange 45 f. This can suppress vibration of the terminal block 45.

As shown in fig. 9 or 10, the upper opening (upper opening 55 in fig. 7) of the terminal box 26b is covered with the cover member 50. Lid member 50 abuts against abutting surface 50s that surrounds the upper opening of terminal box 26 b. The abutting surface 50s is a flat surface formed at the upper edge of the back surface portion 38b, the upper edge of the partition wall 44, and the upper edge of the case side wall 26 f.

A seal is provided on the abutting surface 50s to seal a gap between the abutting surface 50s and the lid member 50. The seal is for example a gasket. The pad is a liquid material applied to the abutting surface 50s, and is cured immediately after application. Alternatively, the gasket is a sheet-like metal gasket. In this way, by interposing a seal in the gap between the abutting surface 50s and the cover member 50, it is possible to prevent rainwater and the like from entering the terminal box 26 b. Therefore, the power line terminals 43b are not short-circuited to each other within the tank space T.

Incidentally, referring to fig. 8, the stator 24 includes concentrated windings as the coils 24 c. This reduces the coil end height Hc (fig. 10), and shortens the axial dimension. In the present embodiment, the number of grooves is "12".

Incidentally, as for the bearing 28 that rotatably supports the rotor 23, referring to fig. 10, a preload spring 28s is disposed on the other side in the axis M direction than the bearing 28. The preload spring 28s is supported by the motor case cover 25v from the other side in the direction of the axis M, and presses the outer race 28M (or the inner race 28n) of the bearing 28 in the direction of the axis M. This applies a preload to the bearings 27 and 28, and the motor rotary shaft 22 is aligned with the axis M, thereby suppressing vibration of the motor rotary shaft 22.

Fig. 11 is a view showing the motor rotary shaft 22 and the rotor 23 taken out from the motor unit 21. Incidentally, the rotor 23 includes a plurality of rotor core segments (segments) 23b, 23b divided in the direction of the axis M. A plurality of grooves 23d extending parallel to the axis M are formed in the outer peripheral portion of each rotor core segment 23 b. The groove 23d is disposed to correspond to a pair of permanent magnets 23c, 23c described later. The adjacent rotor core segments 23b, 23b are arranged with a shift in the circumferential direction and are different in phase from each other. The rotor core associated with the phase dislocation opening angle Rs is referred to as a rotor core having a mechanical angle or a rotor core in which segment skew is performed. In the present embodiment, the rotor core of the rotor 23 is divided into two parts to subject the rotor core to two-stage skew. By performing the step skew on the rotor core and providing a plurality of pairs of groove portions 23d, 23d on the outer peripheral portion of the rotor core, the cogging torque of the motor portion 21 can be reduced and the driving force can be improved.

Fig. 12 is a transverse sectional view showing the motor rotary shaft 22, the rotor 23, and the stator 24. A key 22k is interposed between the outer peripheral surface of the motor rotary shaft 22 and the inner peripheral surface of the rotor 23 fitted to each other. The key 22k is engaged with a notch formed in the outer peripheral surface of the motor rotary shaft 22 and a notch formed in the inner peripheral surface of the rotor 23, and prevents the motor rotary shaft 22 and the rotor 23 from rotating relative to each other.

Inside the rotor 23, a plurality of pairs of permanent magnets 23c and 23c are arranged at intervals in the circumferential direction. Since the present embodiment has eight pairs of permanent magnets 23c, the number of magnetic poles is 8. The pair of permanent magnets 23c, 23c are arranged so as to face each other in the circumferential direction, and so as to have a so-called V-shape in which the inner diameter side ends closer to the axis M are closer to each other and the outer diameter side ends farther from the axis M are farther from each other, as viewed in the direction of the axis M. With the magnet arrangement described above, reluctance torque can be effectively utilized. The pair of grooves 23d, 23d are arranged at the same circumferential position as the outer diameter side ends of the pair of permanent magnets 23c, 23 c. That is, the pair of permanent magnets 23c, 23c are disposed apart from each other in the circumferential direction from the center of each magnetic pole. The number of the grooves 23d is also eight pairs as many as the number of the permanent magnets 23 c.

A bolt 23e is inserted through a through hole formed in the rotor 23. The bolt 23e extends in the axis M direction through the rotor core segment 23b (fig. 11) on one side in the axis M direction and the rotor core segment 23b (fig. 11) on the other side in the axis M direction. The rotor core segments 23b and 23b are coupled to each other by bolts 23 e.

Although the embodiments of the present invention have been described above with reference to the drawings, the present invention is not limited to the configurations of the illustrated embodiments. Various modifications and variations can be made to the illustrated embodiments within the same scope as or an equivalent scope to the present invention.

[ INDUSTRIAL APPLICABILITY ]

The in-wheel motor drive according to the invention can be used advantageously in electric vehicles and hybrid vehicles.

[ notation ] to show

10 in-wheel motor drive device, 11 in-wheel bearing portion, 12 inner race (hub wheel), 21 motor portion, 22 motor rotation shaft, 23 rotor, 24 stator, 24b stator core, 24c coil, 24d protrusion, 24h through hole, 25 motor case, 25c connecting wall, 25d abutting surface, 25f bulging portion, 25g approaching portion, 25j outer wall, 25v motor case cover, 26b power line terminal box, 26c signal line terminal box, 26d protrusion, 26e case top wall, 26f case side wall, 29 case supporting portion, 29b first supporting portion, 29c second supporting portion, 29d third supporting portion, 29 d' protrusion wall, 30 rotation preventing pin, 31 speed reducing portion, 32s input shaft, 37 output shaft, 38 body case, 38b back surface portion, 38c case base portion, 38d female screw hole, 38f front surface portion, 39 oil portion, 41 coil terminal, angle sensor 52, oil receiving port 53, bracket member 61, G gap, M, N, O axis.

Claims (5)

1. An in-wheel motor drive device is provided with:

a hub bearing unit for rotatably supporting a hub ring coupled to a wheel; and

a motor unit that drives the hub ring,

the motor unit includes: a motor rotating shaft extending in the vehicle width direction; a rotor coupled to the motor rotation shaft; a cylindrical stator facing the rotor with a gap therebetween; and a motor case surrounding an outer circumference of the stator,

the motor housing has: a first support portion that is disposed above an axis of the motor rotating shaft, and that supports the stator by being in surface contact with an outer peripheral surface of the stator; a second support portion that is disposed below the axis of the motor rotating shaft, and that supports the stator by making surface contact with the outer peripheral surface of the stator; and a third support portion that is disposed in front of or behind the vehicle so as to cross an axis of the motor rotary shaft when viewed from the first support portion or the second support portion, and that supports the stator by coming into surface contact with an outer peripheral surface of the stator,

the first support portion, the second support portion, and the third support portion are arranged with a gap in the circumferential direction.

2. The in-wheel motor drive arrangement according to claim 1,

the motor case further includes a wall portion that branches from any one of the first support portion, the second support portion, and the third support portion and extends.

3. The in-wheel motor drive arrangement according to claim 1,

the motor housing further has: an outer wall formed at a position outside the inner wall with any one of the first support portion, the second support portion, and the third support portion as the inner wall; and a connecting wall connecting the inner wall with the outer wall,

the connecting walls are arranged at two positions at intervals and form a box body together with the inner wall and the outer wall.

4. The in-wheel motor drive arrangement according to claim 3,

the inner space of the motor case is set to an oil atmosphere,

the case is disposed below the motor rotation shaft,

the outer wall is disposed below the inner wall and protrudes in the axial direction of the motor unit from the inner wall, and a lubricant oil receiving opening is formed between the outer wall and an end edge of the inner wall in the axial direction,

the lubricant oil flows from the internal space to the lubricant oil receiving port.

5. The in-wheel motor drive arrangement according to claim 3 or 4,

the outer wall is an inclined wall disposed so as to be separated from the inner wall on one side and to be close to the inner wall on the other side in the axial direction of the motor rotating shaft.

Images