CN111758205A

CN111758205A - Motor drive device for vehicle

Info

Publication number: CN111758205A
Application number: CN201980012064.4A
Authority: CN
Inventors: 竹内直哉; 田村四郎; 太向真也
Original assignee: NTN Corp
Current assignee: NTN Corp
Priority date: 2018-02-08
Filing date: 2019-02-06
Publication date: 2020-10-09
Also published as: JP2019140770A; WO2019156119A1; JP7207852B2

Abstract

A motor drive device (10) for a vehicle is provided with a cylindrical stator (24), a motor housing (25) surrounding the outer periphery of the stator (24), a housing base supporting one end of the stator (24), a motor housing cover covering the other end of the stator (24), and a fixing mechanism (51) arranged at a predetermined circumferential position around an axis (M) and fixing the stator (24) to the housing base, wherein the motor housing (25) and the motor housing cover respectively have abutting surfaces (24d) abutting against each other in the direction of the axis (M), the abutting surfaces (25d) of the motor housing (25) are in a shape surrounding the outer periphery of the stator (24) and include an approaching portion (25g) extending along the outer periphery of the stator (24) and a bulging portion (25f) protruding radially outward so as to be separated from the outer periphery of the stator (24), the circumferential position of the fixing mechanism (51) is arranged to overlap the circumferential position of the bulging portion (25 f).

Description

Motor drive device for vehicle

Technical Field

The present invention relates to a motor drive device for driving a wheel, and more particularly to a structure in which a stator of a motor unit is fixed 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 stator housed in a case, and the stator core is made to protrude radially outward as an abutment portion at circumferential positions of three points around the center of a stator core. The stator core abutment portion abuts against the inner peripheral surface of the housing. The fastening member that penetrates the stator core and fastens the stator core to the housing is a long-necked bolt, and is disposed so as to be included in a circumferential position of the stator core contact portion.

According to the disclosure of patent document 1, the stator core abutting portion 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 ]

However, noise and vibration of the motor (rotating electrical machine) are caused by various factors in addition to the misalignment between the rotor and the stator as described above. In other words, even if the rotor and the stator are held coaxially, the minute vibration of the stator itself may be transmitted to another component of the motor, and unpleasant noise may be generated from the component.

The present inventors have found the following: when the motor is driven, the circular cover covering the axial end face of the motor vibrates as a film and becomes a noise source.

According to the motor described in patent document 1, the stator core protrudes outward in the outer diameter direction and comes into contact with the housing at a portion close to the head of the fastening member (bolt), that is, in the vicinity of the circular cover. A fixed circular cover is attached to the vicinity of the contact portion. Therefore, when the stator itself vibrates slightly, the slight vibration is transmitted to the circular cover without being attenuated, and the circular cover is excited, which becomes an unpleasant noise source.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a technique for avoiding a cover covering an end face of a stator from becoming a noise source in a motor drive device that drives a wheel.

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

In order to achieve the object, a motor drive device for a vehicle according to the present invention includes a motor unit for driving a wheel, the motor unit including a motor rotating shaft, a rotor coupled to the motor rotating shaft, a cylindrical stator facing the rotor with a gap therebetween, a motor housing surrounding an outer periphery of the stator, a housing base supporting one end of the stator, a motor housing cover covering the other end of the stator, and a fixing mechanism disposed at a predetermined circumferential position around the motor rotating shaft and fixing the stator to the housing base, the motor housing and the housing cover each having an abutting surface abutting against each other in an axial direction, the abutting surface of the motor housing being formed in a shape surrounding an outer periphery of the stator and including a proximal portion extending along the outer periphery of the stator and a bulging portion protruding radially outward so as to be separated from the outer periphery of the stator, the predetermined circumferential position at which the fixing mechanism is disposed overlaps the circumferential position of the bulging portion.

According to the present invention described above, the motor case is separated from the fixing mechanism. The motor case is also separated from the portion of the stator coupled to the fixing mechanism. In particular, the abutting surface between the motor case and the motor case cover is separated from the fixing mechanism and also separated from the portion of the stator coupled to the fixing mechanism. Therefore, even if the stator itself vibrates slightly while the motor portion drives the wheel, the motor housing cover abutting the motor housing at the abutting surface is hardly excited. Therefore, according to the present invention, it is possible to reduce the film vibration of the motor case cover covering the end face of the stator, thereby suppressing unpleasant noise.

As one aspect of the present invention, the motor case includes a box-shaped terminal box that houses at least one of a coil terminal extending from a coil provided in the stator, an end of a power line drawn from outside of the vehicle motor drive apparatus, a terminal of a lead wire extending from a sensor provided inside of the vehicle motor drive apparatus, and an end of a signal line drawn from outside of the vehicle motor drive apparatus, and the bulging portion of the abutting surface constitutes an outline of the terminal box. According to the above aspect, the bulging portion also serves as the terminal box, and therefore, the space between the bulging portion and the stator can be effectively utilized as the internal space of the terminal box. Alternatively, only a gap may be provided between the bulge portion and the stator.

In a preferred aspect of the present invention, the fixing means is a bolt extending parallel to the motor rotation shaft and penetrating through the stator, a tip of a shaft portion of the bolt is screwed into a female screw hole provided in the housing base, and a head portion of the bolt abuts against the stator. According to the above aspect, the stator is reliably fixed by bolt fastening so as not to be displaced in the axial direction. The length of the bolt is not particularly limited. For example, the bolt is longer than the stator and penetrates from the other end of the stator in the axial direction to one end of the stator in the axial direction. As another example, the bolt may be shorter than the stator, a flange portion may be provided at one end portion of the stator in the axial direction, and a protrusion protruding to the outer diameter side may be provided, a through hole may be provided in the flange portion or the protrusion, and the bolt may be inserted through the through hole and fastened.

In a more preferred aspect of the present invention, the stator has a projection projecting from an outer peripheral surface of the stator, the fixing mechanism fixes the projection of the stator to the housing base, and the motor housing has a projection projecting outward in a radial direction so as to be spaced apart from the projection of the stator. According to the above aspect, the protrusion provided on the stator realizes a structure for attaching the stator to the housing of the motor drive device for a vehicle. Further, since the protruding portion of the motor case protrudes so as to avoid the protrusion of the stator, the inner circumferential surface of the motor case is separated from the outer circumferential surface of the stator, and vibration of the stator is less likely to be transmitted to the motor case cover. The protrusion may be provided at one end portion in the axial direction of the stator as a flange, or may extend from one end portion to the other end portion in the axial direction of the stator as a bar. Preferably, the protrusions are provided at predetermined circumferential positions of the stator so as to correspond to the circumferential arrangement of the fixing means. Alternatively, a cylindrical or polygonal stator may be attached to the housing base without providing a protrusion on the stator.

The motor drive device for a vehicle according to the present invention is provided at any position of an electric vehicle. As one aspect of the present invention, the motor drive device for a vehicle further includes a hub bearing portion rotatably supporting a hub wheel coupled to the wheel, and is disposed in the hollow region of the wheel. According to the above aspect, in the in-wheel motor drive device disposed in the hollow area of the travel wheel, unpleasant noise generated from the motor case cover of the motor unit can be suppressed. Alternatively, the vehicle motor drive device may be an in-vehicle motor drive device mounted on a vehicle body. The in-vehicle motor drive device is connected to the wheel via a constant velocity joint and a drive shaft.

[ Effect of the invention ]

As described above, according to the present invention, in the motor for driving the wheel, it is possible to reduce the occurrence of film vibration in the motor case cover provided at the end of the motor and covering the end face of the stator inside the motor, and it is possible to suppress the occurrence of unpleasant noise from the motor case cover.

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 a motor unit according to the embodiment.

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 case 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 shows the front of the vehicle, the left side of the drawing shows the rear of the vehicle, the upper side of the drawing shows the upper side of the vehicle, and the lower side of the drawing shows 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.

As shown in fig. 2, the in-wheel motor drive device 10 includes a hub bearing portion 11 provided at the center of an unillustrated wheel, 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 reduced speed 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 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. The through holes extend parallel to the axis O, and the bolt 15 is inserted through the through holes 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 these holes from 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 constituting 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 race 12 is coupled to a running wheel of the wheel via a coupling portion 12f, and rotates 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 and spline-fitted into the center hole at the other end of the inner race 12 in the axis O direction.

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 portion 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 38f 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 and 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.

As shown in fig. 1, the motor housing 25 is formed in a substantially cylindrical shape as a base body and has 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 protruding upward, a box-shaped signal line terminal box 26c protruding rearward of the vehicle, and a semi-cylindrical protruding portion 26d protruding forward of the vehicle. 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.

Portions between these three circumferentially separated projections in the motor case 25 constitute

cylindrical portions

29, 29. The inner wall surfaces of the

cylindrical portions

29, 29 are cylindrical surfaces centered on the axis M.

Power wire terminal box 26b accommodates three coil terminals 41 drawn from the end (coil end) of stator 24 in the direction of axis M. Three power lines (not shown) extending from the outside of in-wheel motor drive device 10 are drawn into power line terminal box 26b, and the end portions of the respective power lines are connected to respective coil terminals 41 via a connector structure (not shown).

In the signal terminal box 26c, end portions (not shown) of lead wires extending from a plurality of sensors such as the rotation angle sensor 52, the temperature sensor (not shown), and the 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 which is exposed by removing the motor housing cover 25v from the motor housing 25. In order to avoid complication of the drawing, in fig. 1, the end face of the stator 24 is simplified by hatching, and a part of the structure in which the rotor, the motor rotation shaft, and the stator 24 are fixed to the rear surface portion 38b is omitted from illustration.

The inner peripheral surfaces of the

cylindrical portions

29, 29 are in contact with the outer peripheral surface of the stator 24. By supporting the outer peripheral surface of the stator 24 from the outer diameter side by the three

cylindrical portions

29, 29 arranged apart in the circumferential direction in this way, the stator 24 is positioned coaxially with the axis M. The stator 24 and the motor case 25 may be press-fitted to each other.

A groove-like notch 25g is formed in the inner wall surface of the motor case 25 adjacent to the cylindrical portion 29. Also, a groove-like notch 24g is formed in the outer peripheral surface of the stator 24 in the same manner. 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 the round bar-shaped rotation preventing pin 30 is inserted between the

notches

24g and 25 g. In the present embodiment, the rotation preventing pins 30 are provided at a plurality of positions in the circumferential direction. By using the rotation preventing pin 30 as an elastic member, transmission of vibration of the stator 24 to the motor case 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 is interposed 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 38 b.

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, in 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, respectively, out of 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 extends 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) through 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 speed reducer 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 32s, a plurality of

intermediate gears

33, 35, an intermediate shaft 34 coupled to centers of the

intermediate gears

33, 35, an output shaft 37 coaxially coupled to the inner ring 12 of the hub bearing unit 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 constitutes 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 a hollow hole of the 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 center 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 an interval 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 34 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 speed reducer 31 reduces the rotation of the input shaft 32s and transmits the rotation to the output shaft 37 by meshing the small-diameter drive gear with the large-diameter -driven gear, that is, by meshing the input gear 32 with the first intermediate gear 33 and by meshing the second intermediate gear 35 with 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 joined 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, the lower portion of the main body case 38 serves as an oil reservoir 39. The oil reservoir 39 is disposed at a position lower than the motor unit 21. The oil reservoir 39 in the lower portion of the main body case 38 occupying the internal space stores lubricating oil for lubricating the motor unit 21 and 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. These rolling

bearings

32m, 34m, 37m, 32n, 34n, 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 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 is disposed so as to overlap the rolling bearing 37m with respect to the position in the axis O direction, and the dimension in the axis direction 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, a supplementary description will be given of a structure in which the stator of the motor unit is fixed to the housing of the in-wheel motor drive device.

Fig. 3 is a vertical cross-sectional view schematically showing a state where the motor portion is cut by a plane shown in III-III of fig. 1 and the cross-section is viewed from the direction of an arrow, and shows a cross-section different from that 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. These abutting surfaces 25d are disposed at the other end of the motor unit 21 in the direction of the axis M. 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.

A housing base 38c is provided at one end of the stator 24 in the axis M direction. The case base 38c is provided on the other side wall surface of the back surface portion 38b in the axis M direction, and protrudes from the other side wall surface on the inner diameter side of the case base 38c toward the other side wall surface in the axis M direction. The projecting end of the case base 38c is provided as a flat surface perpendicular to the axis M. An internal threaded hole 38d is formed at the projecting end of the housing base 38 c. The internally threaded hole 38d is directed to the other side in the direction of the axis M. Case base 38c is arranged at the same circumferential position as power line terminal box 26 b. The other case base 38c is arranged 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. The rear surface portion 38b has a central hole 38e through which the motor rotary shaft 22 passes, and the rolling bearing 27 is coaxially provided adjacent to the central hole 38 e.

The bolt 51 as a fixing means is inserted through the through hole 24h of the stator 24 from the other side in the axis M direction. When the tip end portion of the bolt 51 is screwed into the female screw hole 38d of the housing base 38c and the head portion of the bolt 51 is screwed in, 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 mounted and fixed so as not to be movable in the direction of the axis M.

Incidentally, the motor case 25 is partially formed as a double wall. For example, the lower portion of the motor housing 25 has a cylindrical portion 29 as an inner wall, and an inclined wall 25n having one side in the direction of the axis M low and the other side in the direction of the axis M high as an outer wall.

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

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 that projects outward in the radial direction so as to be spaced apart from the outer peripheral surface of the stator 24.

As shown in fig. 1, the through hole 24h is disposed so that its circumferential position overlaps with the circumferential position of the protruding portion 26d with respect to the axis M of the motor unit 21. The circumferential position of the through hole 24h is arranged to overlap the circumferential position of the power wire terminal box 26 b. The circumferential position of the through hole 24h is arranged to overlap the circumferential position of the signal line terminal box 26 c. That is, the circumferential position of the bolt 51 (fig. 3) as the stator fixing means inserted through each through hole 24h is arranged to overlap the circumferential position of the bulging portion 25 f.

The in-wheel motor drive device 10 of the present embodiment includes a motor unit 21 that drives a wheel. The motor unit 21 includes a motor rotation shaft 22, a rotor 23 coupled to the motor rotation shaft 22, a cylindrical stator 24 facing the rotor 23 with a gap therebetween, a motor housing 25 surrounding an outer periphery of the stator 24, a housing base 38c supporting one end of the stator 24 in the axis M direction, a motor housing cover 25v covering the other end of the stator 24 in the axis M direction, and a bolt 51 (fixing means) disposed at a predetermined circumferential position around the motor rotation shaft 22 and fixing the stator 24 to the housing base 38 c. The motor housing 25 and the motor housing cover 25v each have an abutting surface 25d abutting against each other in the axis M direction. As shown in fig. 1, the abutting surface 25d of the motor case 25 is shaped to surround the outer peripheral surface of the stator 24, and includes an approaching portion 25g extending along the outer peripheral surface of the stator 24 and a bulging portion 25f projecting radially outward so as to be spaced apart from the outer peripheral surface of the stator 24. The predetermined circumferential position where the bolt 51 is disposed overlaps the circumferential position of the bulging portion 15 f.

According to the present embodiment described above, the motor case 25 is separated from the bolt 51. The motor case 25 is also separated from the projection 24d of the stator 24 coupled to the bolt 51. Therefore, even if the stator 24 itself vibrates slightly when the motor unit 21 drives the wheel, the vibration is mainly transmitted to the housing base 38c via the bolt 51, and thus the vibration transmitted to the motor housing 25 can be reduced. Therefore, the motor housing cover 25v abutting the motor housing 25 at the abutting surface 25d is hardly excited. According to the present invention, it is possible to reduce the film vibration of the motor housing cover 25v covering the other end surface of the stator 24 in the axis M direction, thereby suppressing unpleasant noise.

Further, the motor case 25 of the present embodiment includes: a box-shaped power line terminal box 26b for housing an end portion of a power line extending from a coil 24c provided in the stator 24 and the coil terminal 41; and a signal line terminal box 26c extending from a sensor provided inside the vehicle motor drive device. The bulging portion 25f of the abutting surface 25d has the contour of the terminal box. According to the present embodiment described above, since the bulging portion 25f also serves as a terminal box, the space between the bulging portion 25f and the stator 24 can be effectively utilized as the terminal box.

In the present embodiment, the fixing means for fixing the stator 24 to the housing base 38c is a bolt 51 extending parallel to the motor rotary shaft 22 and penetrating the stator 24, a tip of a shaft portion of the bolt 51 is screwed into a female screw hole 38d provided in the housing base 38c, and a head portion of the bolt 51 abuts against the other end of the stator 24 in the axis M direction. Thereby, the stator 24 is reliably fixed by bolt fastening so as not to be displaced in the axis M direction.

The stator 24 of the present embodiment has a projection 24d projecting from the outer peripheral surface of the stator 24, and the projection 24d is fixed to the housing base 38c by a bolt 51 serving as a mechanism for fixing the stator 24. The motor housing 25 has a protruding portion 26d protruding outward so as to be separated from the ridge 24 d. The ribs 24d provide a structure for mounting the stator 24 to the housing of the in-wheel motor drive 10.

Although the embodiments of the present invention have been described above with reference to the drawings, the present invention is not limited to 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 motor drive apparatus for a vehicle according to the present invention can be advantageously used in electric vehicles and hybrid vehicles.

[ notation ] to show

10-in-wheel motor drive device, 11-in-wheel bearing portion, 12-inner ring, 21-motor portion, 22-motor rotating shaft, 23-rotor, 24-stator, 24-b-stator core, 24-c coil, 24-d projected strip (projection), 24-h through hole, 25-motor housing, 25-d butt surface, 25-G approach portion, 25-f bulge portion, 25-v-motor housing cover, 26-b power line terminal box (projection), 26-c signal line terminal box (projection), 26-d projection, 29-cylinder portion, 30-rotation preventing pin, 31-speed reduction portion, 38-body housing, 38-b back surface portion, 38-c housing base, 38-d internal thread hole, 51-bolt (fixing mechanism), 61-bracket member, G-gap, M, N, O axis.

Claims

1. An electric motor driving device for a vehicle, wherein,

the motor driving device for a vehicle includes a motor unit for driving a wheel,

the motor unit includes: a motor rotating shaft, a rotor coupled to the motor rotating shaft, a cylindrical stator facing the rotor with a gap therebetween, a motor housing surrounding an outer periphery of the stator, a housing base supporting one end of the stator, a motor housing cover covering the other end of the stator, and a fixing mechanism disposed at a predetermined circumferential position around the motor rotating shaft and fixing the stator to the housing base,

the motor housing and the housing cover each have an abutting surface abutting against each other in the axial direction,

the abutting surface of the motor case is formed in a shape surrounding an outer peripheral surface of the stator, and includes a proximal portion extending along the outer peripheral surface of the stator and a bulging portion projecting to an outer diameter side so as to be separated from the outer peripheral surface of the stator,

the predetermined circumferential position at which the fixing mechanism is disposed overlaps with a circumferential position of the bulging portion.

2. The vehicular electric motor drive apparatus according to claim 1, wherein,

the motor case includes a box-shaped terminal box that houses at least one of a coil terminal extending from a coil provided in the stator, an end of a power line drawn from outside the vehicle motor drive device, a terminal of a lead wire extending from a sensor provided inside the vehicle motor drive device, and an end of a signal line drawn from outside the vehicle motor drive device,

the bulging portion of the mating face constitutes an outline of the terminal box.

3. The vehicular electric motor drive apparatus according to claim 1 or 2, wherein,

the fixing means is a bolt extending parallel to the motor rotation shaft and penetrating the stator,

the tip of the shaft portion of the bolt is screwed into an internal threaded hole provided in the housing base,

the head of the bolt abuts against the stator.

4. The vehicular electric motor drive apparatus according to any one of claims 1 to 3, wherein,

the stator has a protrusion protruding from an outer circumferential surface of the stator,

the securing mechanism secures the protrusion to the housing base,

the motor housing has a protruding portion protruding outward in the radial direction so as to be separated from the protrusion.

5. The vehicular electric motor drive apparatus according to any one of claims 1 to 4, wherein,

the vehicle motor driving device further includes a hub bearing portion rotatably supporting a hub ring coupled to the wheel, and is disposed in the hollow area of the wheel.