JP2021075201A - In-wheel motor driving device - Google Patents

Abstract

To accurately position and fix a resolver and maintain the position accuracy to enable the resolver to continuously achieve excellent detection performance while avoiding interference between an in-wheel motor driving device and peripheral components.SOLUTION: An in-wheel motor driving device 21 includes: a motor part A which drives a wheel; a wheel bearing part C which rotationally supports the wheel; a resolver D which detects a rotation angle of the motor part A; and a casing 22 which houses at least the motor part A. The resolver D includes: a rotor 55 which is attached to a rotary shaft 26 of the motor part A; a stator 56 attached to the casing 22; and a pressing plate 58 which presses the stator 56 in an axial direction between itself and the casing 22. The pressing plate 58 integrally has: claw parts 60 which press the stator 56 in the axial direction at circumferential positions; and bolt fixing parts 61, each of which is provided at a position different from the claw part 60 in a circumferential direction and fixed to the casing 22 by a bolt 59.SELECTED DRAWING: Figure 3

Description

The present invention relates to an in-wheel motor drive device.

As the in-wheel motor, there are known a direct method in which the rotational driving force of the motor is directly transmitted to the wheels and a reduction gear combined method in which the rotational driving force of the motor is decelerated by the reduction gear and transmitted to the wheels.

Further, in this type of in-wheel motor, in addition to a motor, a speed reducer, a bearing for wheels, and a casing for accommodating the motor, an angle sensor for detecting the rotation angle of the motor is further provided. Are known. In this case, as the angle sensor applied to the above-mentioned motor, a resolver having excellent resistance to changes in the environment as compared with other sensors is preferably used because of its simple structure.

Here, as a structure for attaching the resolver to the motor, for example, as described in Patent Document 1, the stator of the resolver is fitted to a bracket constituting the housing case of the motor and fastened and fixed in the axial direction with bolts. Things are known. Alternatively, as described in Patent Document 2, the resolver stator portion is axially sandwiched between the motor housing (resolver stator portion side mounting portion) and the cover member, and an elastic ring is interposed between the housing and the resolver. It is known that the resolver stator portion is fixed to the housing by tightening and fixing the cover member to the housing with bolts in this state.

Japanese Unexamined Patent Publication No. 2001-78393 Japanese Unexamined Patent Publication No. 2006-280117

By the way, since this type of in-wheel motor is mounted on the undercarriage of a vehicle, it may be necessary to strictly set its outer shape and size in consideration of the positional relationship with the suspension parts and body side parts. is there. For example, when considering assembling a resolver to the rotating shaft of a motor from the inboard side of the in-wheel motor (the inboard side here means the side closer to the center of the vehicle in the axial direction of the target vehicle). As described in Patent Document 1, when the stator of the resolver is to be fixed to the casing by fitting, the fitting surface (inner peripheral surface for fitting and fixing) for fitting with the outer peripheral surface of the stator is attached to the casing. It is necessary to provide it, and it is necessary to increase the outer diameter of the casing by the amount of the fitting surface. This leads to an increase in the diameter of the casing and eventually an increase in the diameter of the in-wheel motor, which may cause interference with the above-mentioned peripheral parts.

On the other hand, as described in Patent Document 2, if the cover member is fixed to the casing with bolts while the resolver stator is sandwiched between the casing and the cover member in the axial direction, the cover member is fitted into the casing as in Patent Document 1. Since it is not necessary to provide a surface for joint fixing, it is possible to prevent the casing and thus the in-wheel motor from being increased in diameter. On the other hand, when an elastic ring is interposed between the casing and the stator as in the mounting structure described in Patent Document 2, the elastic ring deteriorates due to vibration and the position accuracy of the stator deteriorates due to the deterioration. Is a problem. That is, this type of in-wheel motor is usually applied in an environment where unsprung vibration acts. Therefore, the elastic ring deteriorates under the action of continuous vibration, and the axial pressing function of the stator is lowered, so that the positioning accuracy of the stator is lowered and the detection accuracy of the resolver may be lowered.

In view of the above circumstances, in the present specification, the resolver is accurately positioned and fixed while avoiding interference between the in-wheel motor drive device and peripheral parts, and excellent detection by the resolver is performed by maintaining this position accuracy. Making it possible to continuously demonstrate performance is a technical issue to be solved.

The solution to the above problems is achieved by the in-wheel motor drive device according to the present invention. That is, this drive device includes a motor unit that drives the wheels, a wheel bearing unit that rotationally supports the wheels, a resolver that detects the rotation angle of the motor unit, and at least a casing that accommodates the motor unit. An in-wheel motor drive device having a rotor attached to a rotating shaft of a motor unit and a stator attached to a casing, further provided with a holding plate that holds the stator between the casing in the axial direction, and the holding plate is a circle thereof. It is characterized by having a plurality of claws that press the stator axially at multiple positions in the circumferential direction and a bolt fixing portion that is provided at different positions in the circumferential direction from the claw and is fixed to the casing with bolts. Attached.

As described above, the in-wheel motor drive device according to the present invention is provided with a holding plate that presses the stator of the resolver in the axial direction between the resolver and the casing, and the holding plate holds the stator at a plurality of positions in the circumferential direction in the axial direction. A plurality of claws to be pressed down and a bolt fixing portion are integrally provided at different positions in the circumferential direction from the claws. In this way, by providing a plurality of claws and bolt fixing portions, both of which form a part of the holding plate, at different positions in the circumferential direction of the holding plate, a sufficient distance between the claws and the bolt fixing portions is obtained. In this state, the holding plate can be bolted to the casing. As a result, the claw portion (or the portion extending from the bolt fixing portion to the claw portion) can be elastically deformed in the axial direction relatively easily. Therefore, as described in Patent Document 2, an elastic ring is formed between the stator and the casing. The stator can be positioned and fixed in the axial direction by absorbing variations in the axial dimensions of the stator, in other words, elastically adjusting the holding position of the stator end surface by the claws without interposing. Further, if it is a holding plate, it is possible to form a holding plate including a portion that is elastically deformed by a material resistant to vibration such as metal, so that in an environment where vibration peculiar to an in-wheel motor drive device such as unsprung vibration acts. However, excellent positioning accuracy can be maintained. Therefore, it is possible to continuously and stably exhibit the excellent detection performance of the resolver.

Further, as in the present invention, by providing the claw portion of the holding plate and the bolt fixing portion at different positions in the circumferential direction, the bolt fixing portion can be arranged in the radial direction without interfering with the claw portion. it can. This makes it possible to prevent the outer diameter of the holding plate from increasing, and to prevent the casing and thus the in-wheel motor drive device from becoming larger. Therefore, the resolver can be positioned with high accuracy while avoiding interference between the in-wheel motor drive device and peripheral parts. Of course, according to the present invention, since the stator can be sandwiched and fixed by bolts, it is not necessary to extend the casing to the outer diameter side in order to provide the fitting and fixing surface as in Patent Document 1. Therefore, this also makes it possible to prevent the casing and thus the in-wheel motor drive device from becoming large in size, and to avoid interference with peripheral parts.

Further, in the in-wheel motor drive device according to the present invention, the bolt fixing portion may be provided between the claw portions adjacent to each other in the circumferential direction of the holding plate.

In this way, by providing the bolt fixing portions between the claws adjacent to each other in the circumferential direction of the holding plate, the elastic restoring force can be effectively applied to a plurality of claws with a minimum number of bolt fixing portions. Can be granted. Therefore, according to the above configuration, it is possible to exhibit good positioning performance while further reducing the size of the entire holding plate.

Further, in this case, in the in-wheel motor drive device according to the present invention, the claws may be provided at three or more positions in the circumferential direction of the holding plate.

By providing the claws at least at three positions in the circumferential direction of the pressing plate in this way, the stator can be reliably pressed in the axial direction without tilting. Therefore, it is possible to stably obtain excellent positioning accuracy.

Further, in the in-wheel motor drive device according to the present invention, the claw portion and the bolt fixing portion are connected to each other in the circumferential direction of the holding plate via the arm portion, and the arm portion bulges outward in the radial direction of the holding plate. It may have a curved shape as described above.

In this way, the claw portion and the bolt fixing portion are connected via the arm portion, and the arm portion is curved so as to bulge outward in the radial direction of the holding plate, thereby preventing unnecessary interference with the stator. While avoiding it, it is possible to secure a substantially required distance (distance required for the required elastic deformation) between the claw portion and the bolt fixing portion. Therefore, according to the above configuration, a large elastic deformation can be generated in the arm portion without applying an excessive tightening force, so that it is possible to avoid an increase in the size of the holding plate and easily vary the axial dimensions of the stator. It becomes possible to correspond. In addition, it is possible to obtain sufficient elastic deformation while ensuring the required strength of the holding plate.

Further, in the in-wheel motor drive device according to the present invention, the portion of the outer peripheral edge of the pressing plate located on the outer periphery of the claw portion may be retracted inward in the radial direction of the pressing plate.

When incorporating a resolver into an in-wheel motor, normally, the inboard side of the motor portion of the casing accommodating the motor portion is opened, and the rotor of the resolver is attached to the rotating shaft of the motor portion from this opening to attach the stator. Attach to the casing. Then, after the assembly of the resolver is completed, the opening of the casing is closed with a predetermined cover member, and the cover member is fixed to the casing with a bolt or the like. When the cover member is fixed to the casing with bolts in this way, the insertion space for the bolts is more radial outside than the outer peripheral edge of the resolver stator (diameter than the outer peripheral edge of the holding plate) in order to avoid interference with the holding plate. There is no choice but to use the outer side), and as a result, there is a problem that the diameter of the casing is increased. On the other hand, in the present invention, the portion of the outer peripheral edge of the pressing plate located on the outer periphery of the claw portion has a shape retracted inward in the radial direction of the pressing plate, so that the retracted portion, that is, the outermost diameter of the pressing plate A bolt insertion space can be provided at a position radially inside the portion. Therefore, while both the holding plate and the cover member can be fixed to the casing by bolting, it is possible to prevent the diameter of the cover member and the casing from increasing.

Further, in the in-wheel motor drive device according to the present invention, the holding plate may be made of spring steel.

As described above, any material can be applied to the holding plate as long as it causes the required elastic deformation when it is fixed to the casing with bolts. For example, a steel material is preferable, and among them, a spring steel is preferable. .. Since spring steel has a feature that the elastic range is wider than that of other steel materials, it is possible to relatively easily exert the elastic deformation required for the holding plate while maintaining the strength as the holding plate.

As described above, according to the present invention, the resolver is accurately positioned and fixed while avoiding interference between the in-wheel motor drive device and peripheral parts, and excellent detection by the resolver is achieved by maintaining this position accuracy. It is possible to continuously demonstrate the performance.

It is sectional drawing of the in-wheel motor drive device which concerns on 1st Embodiment of this invention, and is sectional drawing along the QQ line of FIG. It is a partial cross-sectional view of the in-wheel motor drive device along the RR line of FIG. It is a figure which looked at the holding structure (without a cover member) of a resolver in FIG. 1 from the direction of arrow S. It is sectional drawing of the holding structure of the resolver along the TT line of FIG. It is a figure which looked at the holding structure (with a cover member) of a resolver in FIG. 1 from the direction of arrow S.

Hereinafter, the first embodiment of the present invention will be described with reference to FIGS. 1 to 5. In the following description, with the in-wheel motor drive device 21 mounted on the vehicle, the side far from the center of the vehicle in the axle direction of the vehicle is referred to as the outboard side, and the side close to the center of the vehicle is referred to as the inboard side.

FIG. 1 is a vertical cross-sectional view of the in-wheel motor drive device 21 as seen by the QQ line of FIG. 2, and FIG. 2 is one of the in-wheel motor drive devices 21 as seen by the RR line of FIG. It is a front view including a partial cross section. The in-wheel motor drive device 21 is arranged inside, for example, a wheel housing 11 (see FIG. 2) that constitutes a drive wheel (wheel) of an electric vehicle, and has a role of transmitting a driving force to the drive wheel. Is responsible for.

Here, as shown in FIGS. 1 and 2, the in-wheel motor driving device 21 has a motor unit A that generates a rotational driving force and a speed reducer unit that decelerates and outputs the rotational driving force input by the motor unit A. B, a bearing portion C for wheels that transmits the output from the speed reducer portion B to the drive wheels, a resolver D that detects the rotation angle of the motor portion A, and a casing 22 that houses at least the motor portion A and the resolver D. I have.

In the present embodiment, the motor unit A, the speed reducer unit B, and the resolver D are housed in the casing 22. In the present embodiment, as shown in FIG. 1, the casing 22 has a divided (two-divided or three-divided or more) structure in consideration of the assembling property of the parts. In this case, each divided casing is referred to as a first divided casing 22a, a second divided casing 22b, and a third divided casing 22c in this order from the inboard side to the outboard side. Further, the first divided casing 22a located on the most inboard side has an opening on the inboard side, and the opening 22a1 is closed by the cover member 22d. The cover member 22d is attached to the first divided casing 22a by fixing the cover member 22d to the first divided casing 22a with one or more bolts 23.

As shown in FIG. 1, the motor unit A includes a motor stator 24 fixed to a casing 22, a motor rotor 25 arranged so as to face each other on the inner side in the radial direction of the motor stator 24 with a predetermined gap, and a motor rotor 25. A radial gap type motor 27 having a motor rotating shaft 26 arranged inside in the radial direction of the motor rotor 25 and rotating integrally with the motor rotor 25 is provided. The motor 27 can rotate at high speed at, for example, thousands to tens of thousands of revolutions per minute. The motor stator 24 is configured by winding a coil 24b around a magnetic core 24a, and the motor rotor 25 is composed of a permanent magnet or the like.

The outboard side (left side in FIG. 1) of the motor rotating shaft 26 is rotatably supported by bearings 28, and the inboard side (right side in FIG. 1) is rotatably supported by bearings 29 with respect to the casing 22. The pair of bearings 28 and 29 together with the motor 27 constitute the motor unit A.

As shown in FIG. 1, the speed reducer unit B includes an input gear 30, a large-diameter intermediate gear 31, a small-diameter intermediate gear 32, an output gear 33, an input shaft 34, an intermediate shaft 35, and an output shaft 36. Has. Of these, the input gear 30 is integrally formed with the hollow input shaft 34, and the input shaft 34 is spline-fitted (including serration fitting; the same applies hereinafter) to the outboard side end of the motor rotating shaft 26. It is coaxially connected to 26a. In this case, the motor rotation shaft 26 and the input shaft 34 rotate around a common rotation center O1. The large-diameter intermediate gear 31 and the small-diameter intermediate gear 32 are integrally formed with the intermediate shaft 35. In this case, the large-diameter intermediate gear 31 and the small-diameter intermediate gear 32 rotate around a common center of rotation O2. Further, the output gear 33 is integrally formed with the output shaft 36, and rotates around the rotation center O3 which is the central axis of the output shaft 36.

Further, the input shaft 34, the intermediate shaft 35, and the output shaft 36, which are all gear shafts, are arranged in parallel with each other. Of these, the input shaft 34 is supported by a pair of bearings 37 and 38, the intermediate shaft 35 is supported by a pair of bearings 39 and 40, and the output shaft 36 is rotated by the pair of bearings 41 and 42 with respect to the casing 22, respectively. It is freely supported.

Further, as shown in FIG. 1, in the speed reducer unit B, the input gear 30 and the large-diameter intermediate gear 31 mesh with each other, and the small-diameter intermediate gear 32 coaxial with the large-diameter intermediate gear 31 and the output gear 33 mesh with each other. .. At this time, the number of teeth of the large-diameter intermediate gear 31 is larger than the number of teeth of either the input gear 30 or the small-diameter intermediate gear 32, and the number of teeth of the output gear 33 is larger than the number of teeth of the small-diameter intermediate gear 32. It is set. From the above configuration, the speed reducer unit B has a reduction structure for reducing the rotational kinetic force input from the motor rotation shaft 26 in two stages, and has an input gear 30 and an output gear 33, a large diameter intermediate gear 31 and a small diameter intermediate gear. Reference numeral 32 denotes a power transmission path from the input shaft 34 to the output shaft 36.

Further, as shown in FIG. 2, the rotation center of the intermediate shaft 35 is between the rotation center O1 of the input shaft 34 of the speed reducer unit B and the rotation center O3 of the output shaft 36 forming the axle of the wheel bearing portion C. O2 is arranged so as to form a bent shape. By arranging the input shaft 34, the intermediate shaft 35, and the output shaft 36 so that the rotation centers O1 to O3 are close to each other in this way, the outer contour of the in-wheel motor drive device 21 is miniaturized.

Further, known types of gears can be applied as the input gear 30, the intermediate gears 31 and 32, and the output gear 33 constituting the speed reducer unit B. For example, in the present embodiment, a helical gear is used. There is. Helical gears are effective in that the number of teeth that mesh with each other increases at the same time and the tooth contact is dispersed, so that the sound is quiet and the torque fluctuation is small. The module of each gear can be set arbitrarily in consideration of the meshing ratio of the gears and the limit rotation speed, but when considering the meshing ratio of the gears and the limit rotation speed, for example, it is about 1 to 3. It is possible to set.

In the present embodiment, the wheel bearing portion C is composed of an inner ring rotation type wheel bearing 43 (see FIG. 1). The wheel bearing 43 includes a pair of bearing inner rings 44, 45 arranged on the outer periphery of the output shaft 36 as an axle, a bearing outer ring 46 arranged on the outer periphery of the bearing inner rings 44, 45, and a bearing inner ring 44, A double-row inner race 47 formed on the outer peripheral surface of the 45, a double-row outer race 48 formed on the inner peripheral surface of the bearing outer ring 46, and a plurality of rolling elements arranged between the inner race 47 and the outer race 48. This is a double-row angular contact ball bearing including a ball 49 as a bearing and a cage (not shown) for holding each ball 49.

Further, the bearing outer ring 46 is provided with a flange portion 50 extending outward in the radial direction, and the flange portion 50 is connected to the hub attachment 12 of the suspension connecting member by a bolt 51. Further, the hub attachment 12 is connected to the casing 22 (here, the third divided casing 22c on the outboard side) with a bolt 52 at a position different in the circumferential direction or a different position in the radial direction from the connection position with the flange portion 50, for example. Has been done. As a result, the hub attachment 12 is fixed to the in-wheel motor drive device 21.

On the other hand, of the pair of bearing inner rings 44 and 45, the bearing inner ring 44 on the outboard side is fixed to the outer periphery of the output shaft 36 as an axle by spline fitting. The bearing inner ring 44 is provided with a flange portion 53 extending outward in the radial direction. The flange portion 53 is a flange for mounting wheels. For example, as shown in FIG. 1, the brake disc 13 and the wheel 14 of the drive wheel (both are shown by the alternate long and short dash line in FIG. 1) are mounted by the hub bolt 54. .. From the above configuration, the rotational driving force from the motor unit A is transmitted to the drive wheels in a state of being decelerated via the speed reducer unit B.

In the in-wheel motor drive device 21, lubricating oil is supplied to each part by an oil pump (for example, a rotary type) (not shown) for cooling the motor part A and lubricating and cooling the speed reducer part B. The inside of the wheel bearing 43 is lubricated with grease.

The resolver D is for detecting the rotation angle of the motor 27, and is arranged on the inboard side of the motor 27 as shown in FIG. Specifically, the resolver D includes a resolver rotor 55 attached to the inboard side end portion 26b of the motor rotating shaft 26, and a resolver stator 56 attached to the first partition casing 22a. Here, the resolver rotor 55 is fixed to the outer periphery of the inboard side end portion 26b of the motor rotating shaft 26 by a predetermined means (for example, press-fitting), whereby the resolver rotor 55 can rotate integrally with the motor rotating shaft 26.

The resolver stator 56 has an annular shape as a whole, and is formed by laminating, for example, a plurality of disc-shaped steel plates in the thickness direction thereof. One or more coils 57 are wound around the resolver stator 56 (see FIG. 1 for each). In this case, as shown in FIG. 4, the resolver stator 56 is in contact with the stepped portion 22e provided on the inner circumference of the first divided casing 22a. Therefore, in this state, the pressing plate 58 is applied to the resolver stator 56 from the opposite side of the stepped portion 22e, and the bolt 59 is tightened so that the resolver stator 56 is sandwiched between the stepped portion 22e and the pressing plate 58 with axial positioning. Can be fixed. It is preferable to adjust the inner diameter of the inner peripheral surface 22f on the inboard side of the step portion 22e so that the inner peripheral surface 22f has a fitting that allows positioning in the radial direction with respect to the resolver stator 56. In FIG. 4, both the resolver rotor 55 and the motor rotating shaft 26 are omitted.

As shown in FIG. 3, the pressing plate 58 integrates a plurality of claw portions 60 extending inward in the radial direction and a bolt fixing portion 61 for fixing the pressing plate 58 to the first divided casing 22a by bolts 59. Have a target. In this case, the bolt fixing portion 61 is formed with an insertion hole 62 through which the bolt 59 can be inserted (see FIG. 4), and the positions of the fastening hole 22g and the insertion hole 62 provided in the first divided casing 22a. By inserting and tightening the bolts 59 in the same state, the resolver stator 56 can be pressed in the axial direction by the claws 60 provided at a plurality of positions in the circumferential direction of the pressing plate 58.

The claw portion 60 and the bolt fixing portion 61 are provided at different positions in the circumferential direction. Further, the claw portion 60 overlaps with the resolver stator 56 in the radial direction and is located radially outside the outer peripheral edge of the coil 57 (separate in the radial direction). On the other hand, the bolt fixing portion 61 is located radially outside the outer peripheral edge of the resolver stator 56. Therefore, in a state where the pressing plate 58 is pressed against the resolver stator 56 by tightening the bolt 59, only the claw portion 60 comes into contact with the resolver stator 56, and the remaining portion of the pressing plate 58 including the bolt fixing portion 61 interferes with the resolver stator 56. Does not occur.

In the present embodiment, both the claw portion 60 and the bolt fixing portion 61 are formed as a part of the pressing plate 58. The claw portion 60 and the bolt fixing portion 61 are connected to each other by an arm portion 63 extending in the circumferential direction of the holding plate 58. Here, as shown in FIG. 4, the position of the seat surface 61a of the bolt fixing portion 61 (the surface on the side that comes into contact with the first divided casing 22a) in the axial direction is P1, and the seat surface 60a of the claw portion 60 (the resolver stator 56). When the axle direction position P2 of the surface on the side that comes into contact with the axial end surface) is set, the axle direction positions P1 and P2 of these seat surfaces 60a and 61a should be set so as to satisfy the following conditions. .. That is, the seat surface 60a of the claw portion 60 and the seat surface 61a of the bolt fixing portion 61 may or may not be on the same plane in a state where the pressing plate 58 is not deformed at all. When fixed to the casing 22a with the bolt 59, the axle direction position P2 of the seat surface 60a of the claw portion 60 with respect to the axle direction position P1 of the seat surface 61a of the bolt fixing portion 61 is inboard as compared with the state before fixing by the bolt 59. It is important to set the axle direction positions P1 and P2 of the seat surfaces 60a and 61a so as to move reliably to the side. As described above, the resolver stator 56 is often formed by laminating a plurality of steel plates in the thickness direction thereof, so that the axial dimensional variation tends to be large (the dimensional tolerance tends to be large). Therefore, for example, even when the actual axial dimension is the lower limit of the tolerance, the pressing plate 58 (arm portion 63) is elastically deformed, and the resolver stator 56 can be reliably pressed in the axial direction by the claw portion 60. As described above, it is desirable to set the axle direction positions P1 and P2 of the seat surfaces 60a and 61a.

In principle, the arrangement and number of the claws 60 and the bolt fixing portions 61 are arbitrary, but in the present embodiment, the bolt fixing portions 61 are arranged between the claws 60 adjacent to each other in the circumferential direction of the holding plate 58. Has been done. Further, the claw portions 60 are provided at three locations in the circumferential direction of the pressing plate 58 (that is, the number of the claw portions 60 is three). In the illustrated example, since the holding plate 58 has a shape (C shape) in which a part of the holding plate 58 is missing in the circumferential direction, the three claw portions 60 and the two bolt fixing portions 61 are different from each other in the circumferential direction. It is arranged at the position.

Further, in the present embodiment, the arm portion 63 connecting the claw portion 60 and the bolt fixing portion 61 has a curved shape so as to bulge outward in the radial direction of the holding plate 58 (see FIG. 3). As a result, the length of the arm portion 63 can be made as large as possible without increasing the width direction dimension of the arm portion 63, so that the arm portion 63 can be further elastically deformed. Further, since the arm portion 63 is curved so as to bulge toward the outer diameter side, there is no concern that it will interfere with the resolver stator 56.

Further, in the present embodiment, the portion of the outer peripheral edge of the pressing plate 58 located on the outer periphery of the claw portion 60 is retracted inward in the radial direction of the pressing plate 58 (see FIG. 3). Here, as shown in FIG. 1, the cover member 22d is fixed to the first partition casing 22a with bolts 23. Therefore, by designing the outer peripheral edge shape of the holding plate 58 as described above, the bolt 23 can be provided at a position that is radially inward from the outermost diameter portion (the portion in contact with the circumscribed circle) of the cover member 22d. it can. Therefore, while both the holding plate 58 and the cover member 22d can be fixed to the first divided casing 22a by bolting, it is possible to prevent the diameter of the cover member 22d and the first divided casing 22a from increasing in diameter.

The holding plate 58 having the above configuration can be formed of any material, but the holding plate 58 is made of metal, particularly spring steel, in consideration of the elastic deformability of the holding plate 58 when tightening bolts as described above. Is good. Of course, the elastic deformability of the arm portion 63 can be adjusted as appropriate, for example, the thickness dimension of the holding plate 58, the length of the arm portion 63, etc. Therefore, depending on the conditions, it is more versatile than resin or the like, not limited to metal. It is also possible to select low cost materials.

Since the in-wheel motor drive device 21 having the above configuration is housed inside the wheel housing 11 (see FIG. 2) and affects the unsprung load, it is essential to reduce the size and weight. By combining the parallel shaft gear type speed reducer unit B described above with the motor unit A, it is possible to use a motor 27 having a low torque, a high rotation speed, and a small size. As a result, a compact in-wheel motor drive device 21 can be realized, and an electric vehicle having excellent running stability and NVH characteristics can be obtained by suppressing the unsprung weight.

Further, in the in-wheel motor drive device 21 according to the present invention, as described above, the resolver stator 56 is provided with a pressing plate 58 for axially pressing the resolver stator 56 with the casing 22 (first divided casing 22a), and the pressing plate 58 is provided. The plate 58 is integrally provided with a plurality of claw portions 60 for axially pressing the resolver stator 56 at a plurality of positions in the circumferential direction, and a bolt fixing portion 61 at different positions in the circumferential direction from the claw portion 60. .. In this way, by providing the plurality of claws 60 and the bolt fixing portions 61, both of which form a part of the pressing plate 58, at different positions in the circumferential direction of the pressing plate 58, the claws 60 and the bolt fixing portions 61 can be connected to each other. The holding plate 58 can be fixed to the first divided casing 22a with bolts 59 while keeping a sufficient distance. As a result, the claw portion 60 or the arm portion 63 which is the connecting portion between the claw portion 60 and the bolt fixing portion 61 can be elastically deformed in the axial direction relatively easily. In other words, the holding plate 58 is a kind of plate. Since it can function as a spring, it absorbs variations in the axial dimensions of the resolver stator 56 and absorbs variations in the axial dimensions of the resolver stator 56 without interposing an elastic ring between the resolver stator 56 and the first split casing 22a as in the conventional case. 56 can be positioned and fixed in the axial direction. Further, if the holding plate 58 is used, the holding plate 58 including a portion elastically deformed by a material resistant to vibration (mainly the arm portion 63 in this case) can be formed, so that the in-wheel motor driving device 21 such as unsprung vibration can be formed. Excellent positioning accuracy can be maintained even in an environment where peculiar vibration acts. Therefore, it is possible to continuously and stably exhibit the excellent detection performance of the resolver D.

Further, as in the present invention, by providing the claw portion 60 of the holding plate 58 and the bolt fixing portion 61 at different positions in the circumferential direction, the bolt fixing portion 61 is radially inside without interfering with the claw portion 60. Can be placed in. As a result, it is possible to prevent the outer diameter of the holding plate 58 from increasing, and to prevent the first divided casing 22a and thus the in-wheel motor drive device 21 from becoming larger. Therefore, the resolver D can be positioned with high accuracy while avoiding interference between the in-wheel motor drive device 21 (particularly, the radial outside of the resolver D mounting portion) and peripheral parts. Of course, according to the present invention, the resolver stator 56 can be fixed to the first divided casing 22a with the bolt 59, so that the first divided casing 22a is extended to the outer diameter side in order to provide the fitting fixing surface as in the conventional case. You don't even have to. Therefore, this also makes it possible to prevent the first division casing 22a and thus the in-wheel motor drive device 21 from becoming large in size, and to avoid interference with peripheral parts.

Hereinafter, an embodiment of the present invention has been described, but the in-wheel motor drive device 21 is not limited to the above embodiment, and can take any form within the scope of the present invention.

For example, in the above embodiment, the case where the claw portions 60 are provided at three locations in the circumferential direction of the pressing plate 58 has been illustrated, but of course, this is not limited to this. The claw portion 60 may be provided at two locations in the circumferential direction, or may be provided at four or more locations. Further, in the above embodiment, the case where the bolt fixing portion 61 is arranged between the claw portions 60 adjacent to each other in the circumferential direction is illustrated, but of course, other arrangement modes can be adopted.

Further, in the above embodiment, the case where the thickness dimension of the claw portion 60 is equal to the thickness dimension of the bolt fixing portion 61 and the arm portion 63 is illustrated, but of course, this is not limited to this. For example, the thickness dimension of the claw portion 60 can be made larger than that of the arm portion 63 (in other words, the thickness dimension of the arm portion 63 can be made smaller than the thickness dimension of the claw portion 60 or the bolt fixing portion 61. It is possible). Alternatively, the thickness of the claw portion 60 may be reduced toward the inside of the pressing plate 58 in the radial direction. Further, the planar shape of the claw portion 60 is not particularly limited, and the claw portion 60 having an arbitrary shape can be adopted as long as a part of the resolver stator 56 in the circumferential direction can be pressed in the axial direction.

Further, in the above embodiment, the case where the arm portion 63 connecting the claw portion 60 and the bolt fixing portion 61 has a curved shape so as to bulge outward in the radial direction of the holding plate 58 has been illustrated (see FIG. 3). Of course, it is also possible to take other shapes. For example, although not shown, the arm portion 63 may have a shape that extends linearly, and the claw portion 60 and the bolt fixing portion 61 may be connected to both ends of the arm portion 63.

Further, in the above embodiment, the case where the claw portion 60, the bolt fixing portion 61, and the arm portion 63 are all integrally formed of the same material has been illustrated, but of course, the present invention is not limited to this. For example, it is possible to form the claw portion 60 separately from the main body of the holding plate 58, and to adopt a structure in which the claw portion 60 is attached to the end portion of the arm portion 63.

11 Wheel housing 12 Hub attachment 13 Brake disc 14 Wheel 21 In-wheel motor drive 22 Casing 22a, 22b, 22c Divided casing 22d Cover member 23 Bolt 24 Motor stator 25 Motor rotor 26 Motor rotating shaft 27 Motor 30 Input gear 31, 32 Intermediate gear 33 Output gear 34 Input shaft 35 Intermediate shaft 36 Output shaft 28, 29, 37, 38, 39, 40, 41, 42 Bearing 43 Wheel bearing 44, 45 Bearing inner ring 46 Bearing outer ring 50, 53 Flange 55 Resolver rotor 56 Resolver Stator 57 Coil 58 Holding plate 59 Bolt 60 Claw part 61 Bolt fixing part 62 Insertion hole 63 Arm part A Motor part B Reducer part C Wheel bearing part D Resolver P1, P2 Axle position

Claims (6)

A motor unit that drives the wheels, a wheel bearing unit that rotationally supports the wheels, a resolver that detects the rotation angle of the motor unit, and a casing that houses at least the motor unit are provided.
The resolver is an in-wheel motor drive device having a rotor attached to a rotating shaft of the motor unit and a stator attached to the casing.
Further provided with a holding plate for axially pressing the stator with the casing
The holding plate has a plurality of claws that press the stator in the axial direction at a plurality of positions in the circumferential direction, and a bolt fixing portion that is provided at different positions in the circumferential direction from the claws and is fixed to the casing with bolts. An in-wheel motor drive device that integrally has. The in-wheel motor drive device according to claim 1, wherein the bolt fixing portion is provided between the claw portions adjacent to each other in the circumferential direction of the holding plate. The in-wheel motor drive device according to claim 1 or 2, wherein the claws are provided at three or more locations in the circumferential direction of the holding plate. The claw portion and the bolt fixing portion are connected to each other in the circumferential direction of the holding plate via the arm portion.
The in-wheel motor drive device according to any one of claims 1 to 3, wherein the arm portion has a shape curved so as to bulge outward in the radial direction of the holding plate. The in-wheel motor drive device according to any one of claims 1 to 4, wherein a portion of the outer peripheral edge of the holding plate located on the outer periphery of the claw portion is retracted inward in the radial direction of the holding plate. The in-wheel motor drive device according to any one of claims 1 to 5, wherein the holding plate is made of spring steel.

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