JP2020051503A - Pre-load application structure of motor support bearing, electric motor, and in-wheel motor drive device - Google Patents

Abstract

To provide a pre-load application structure of a motor support bearing which enables improvement of assemblability of a component.SOLUTION: A protection member 72 includes: a ring part 72a disposed between an elastic member 71 and a bearing 41; a cylinder part 72b which protrudes from the ring part 72a in an axial direction and in which the elastic member 71 is disposed at an outer periphery or an inner periphery; and a restriction part 72e which protrudes from the ring part 72a to the opposite side of the cylinder part 72b and contacts with an inner peripheral surface or an outer peripheral surface of an outer ring 37 of the bearing 41 to restrict radial movement of the protection member 72 relative to the bearing 41.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a preload applying structure for a motor support bearing, an electric motor including the structure, and an in-wheel motor driving device.

  2. Description of the Related Art Conventionally, there has been known a technology of reducing vibration and noise by applying an axial preload to a bearing supporting a rotating shaft of an electric motor using an elastic member such as a wave washer or a spring (for example, , Patent Documents 1 and 2).

  However, in such a preload applying structure, when the state in which the elastic member is completely compressed in the axial direction is repeated, there is a problem that the elastic member is fatigued and deteriorated. The term “deterioration” means that the elastic member is damaged such as a crack or a crack, or that the elastic member is plastically deformed and the free length is shortened. On the other hand, Patent Document 3 proposes a preload applying structure provided with a backing ring as a protection member for protecting the elastic member from being completely compressed.

  Specifically, as shown in FIG. 12, the backing ring 100 has a shoulder portion 100a disposed between the bearing 300 and the spring 200, and the spring 200 is disposed on the outer periphery of the shoulder portion 100a so as to protrude in the axial direction. The spring 200 urges the bearing 300 in the axial direction via the shoulder 100a. When the bearing 300 is displaced to the right in FIG. 12 together with the motor rotation shaft 400, the protrusion 100b of the backing ring 100 is provided on the motor housing 600 before the spring 200 is completely compressed with this displacement. The spring 200 is configured to be prevented from being further compressed by abutting the stopper 500 that has been set.

JP 2009-201255 A JP 2016-32422 A Japanese Patent No. 3133014

  The backing ring 100 and the spring 200 shown in FIG. 12 are housed in a recess 600 a provided in the motor housing 600. Here, the backing ring 100 and the spring 200 need to be accommodated with a certain margin (gap) with respect to the inner surface of the concave portion 600a so that axial displacement is allowed. For this reason, if the opening of the concave portion 600a turns sideways or downwards when assembling the components, the backing ring 100 and the spring 200 may fall off or fall down from the concave portion 600a. As described above, in the conventional configuration, there is a problem in the assemblability of the backing ring 100 and the spring 200 to the concave portion 600a of the motor housing 600, and a countermeasure is required.

  Therefore, an object of the present invention is to provide a preload applying structure of a motor support bearing, an electric motor, and an in-wheel motor drive device, which can improve the assemblability of parts.

  In order to solve the above-described problems, the present invention provides an elastic member that urges a bearing that supports a motor rotation shaft of an electric motor to apply a preload in an axial direction, and that an elastic member is completely compressed in an axial direction. A preload applying structure for a motor support bearing, comprising: a protection member to be prevented; and a casing provided with a recess in which the elastic member and the protection member are housed, wherein the protection member is disposed between the elastic member and the bearing. A ring portion, a cylindrical portion protruding in the axial direction from the ring portion and having an elastic member disposed on the outer periphery or the inner periphery, and an inner peripheral surface or outer periphery of the outer ring of the bearing projecting from the ring portion on a side opposite to the cylindrical portion. A restricting portion that contacts the surface and restricts radial movement of the protection member with respect to the bearing.

  As described above, in the preload applying structure of the motor support bearing according to the present invention, when the protective member has the restricting portion that restricts the radial movement of the protective member with respect to the bearing, it is possible to assemble parts. In addition, by attaching the protective member to the bearing, it is possible to regulate the radial movement of the protective member with respect to the bearing by the restricting portion. This makes it possible to prevent the protective member from being displaced in the radial direction, thereby facilitating assembly work. Further, since the displacement of the protection member is prevented, the displacement of the elastic member mounted on the outer periphery or the inner periphery of the protection member (cylindrical portion) can also be indirectly prevented. Also improve.

  Further, since the restricting portion is configured to be press-fittable to the inner or outer periphery of the outer ring of the bearing, it is possible to prevent the protection member from being separated from the bearing in the axial direction. As a result, the protection member and the bearing can be handled as an integrated unit, so that the assembling work is further facilitated.

  Further, in order to prevent the protection member from being separated from the bearing in the axial direction, the regulating portion may be provided with a convex or concave engaging portion that engages with the outer ring of the bearing.

  It is desirable that the outer diameter of the elastic member be larger than the inner diameter of the outer ring of the bearing. By making the outer diameter of the elastic member larger than the inner diameter of the outer ring of the bearing, an axial preload can be effectively applied to the outer ring, and the protective member is less likely to be deformed.

  As the elastic member, for example, an annular or spiral spring member can be used.

  Further, the preload applying structure according to the present invention supports a casing, a stator fixed to the casing, a motor rotation shaft, a rotor that rotates integrally with the motor rotation shaft, and a motor rotation shaft that is rotatable with respect to the casing. By applying the present invention to an electric motor including a bearing to be applied and a preload applying structure for applying an axial preload to the bearing, the assembling workability is improved.

  Further, the preload applying structure according to the present invention may be provided on both ends of the motor rotation shaft, and individually apply a preload to a pair of bearings supporting the motor rotation shaft.

  Also, an in-wheel including an electric motor having a preload applying structure according to the present invention, an electric motor unit, a wheel bearing unit, and a reduction gear unit that reduces the speed of the rotation of the electric motor unit and transmits the rotation to the wheel bearing unit. It is also possible to apply to a motor drive device.

  According to the present invention, the assemblability of the protective member and the elastic member is improved, so that the assembling work is easily performed.

It is a sectional view of an in-wheel motor drive provided with a precompression giving structure concerning one embodiment of the present invention. It is sectional drawing which expands and shows the preload provision structure and its periphery. It is sectional drawing which shows a mode that a motor rotating shaft is inserted vertically and assembled. It is sectional drawing which shows a mode that an inner cover is assembled from an upper part. It is sectional drawing which shows the state which the cylindrical part of the protection member contacted the recess bottom surface. It is sectional drawing which shows the embodiment in which the cylinder part was arrange | positioned at the inner periphery of the wave spring. It is a sectional view showing an embodiment in which a regulation part is arranged at the perimeter of an outer ring. It is sectional drawing which shows embodiment with the cylinder part arrange | positioned at the inner periphery of a wave spring, and the restricting part arranged at the outer periphery of the outer ring. It is sectional drawing which shows embodiment which provided the engagement part in the restriction | limiting part. It is a top view showing the schematic structure of the electric vehicle carrying the in-wheel motor drive. FIG. 11 is a rear sectional view showing the electric vehicle of FIG. 10. It is sectional drawing which shows the conventional preload provision structure.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings, taking an in-wheel motor drive device arranged in an inner space area of a wheel as an example. The present invention is not limited to the in-wheel motor drive device, but is also applicable to a so-called on-board type electric vehicle drive device in which the drive device is provided on a vehicle body. Further, the on-board type may be either a one-motor type in which one electric motor drives left and right wheels and a two-motor type in which two electric motors drive left and right wheels.

  FIG. 10 is a schematic plan view of the electric vehicle 11 on which the in-wheel motor drive device 21 is mounted, and FIG. 11 is a schematic sectional view of the electric vehicle 11 as viewed from the rear.

  As shown in FIG. 10, the electric vehicle 11 includes a chassis 12, a front wheel 13 as a steering wheel, a rear wheel 14 as a driving wheel, and an in-wheel motor driving device 21 that transmits driving force to the rear wheel 14. To equip. As shown in FIG. 11, the rear wheel 14 is housed inside a wheel casing 15 of the chassis 12 and is fixed to a lower portion of the chassis 12 via a suspension 16.

  The suspension device 16 supports the rear wheel 14 with a suspension arm extending left and right, and absorbs vibration received by the rear wheel 14 from the ground by a strut including a coil spring and a shock absorber to suppress the vibration of the chassis 12. A stabilizer is provided at a connection portion between the left and right suspension arms to suppress a tilt of the vehicle body during turning or the like. The suspension device 16 is of an independent suspension type in which the left and right wheels are moved up and down independently in order to improve the ability to follow the unevenness of the road surface and efficiently transmit the driving force of the rear wheel 14 to the road surface.

  In the electric vehicle 11, the in-wheel motor drive device 21 for driving the left and right rear wheels 14 is provided inside the wheel casing 15, thereby eliminating the need to provide a motor, a drive shaft, a differential gear mechanism, and the like on the chassis 12. Therefore, there is an advantage that a large cabin space can be secured and the rotation of the left and right rear wheels 14 can be controlled.

  Subsequently, before describing the characteristic configuration of the present embodiment, the overall configuration of the in-wheel motor drive device 21 will be described based on FIG. In the following description, when the in-wheel motor drive device 21 is mounted on the vehicle, the side (left side in FIG. 1) that is closer to the outside in the vehicle width direction is called the outboard side, and the side closer to the center (see FIG. 1). 1 is called the inboard side.

  As shown in FIG. 1, the in-wheel motor drive device 21 includes an electric motor unit A that generates a driving force, a speed reducer unit B that reduces the speed of rotation of the electric motor unit A, and outputs a signal. The main components are a wheel bearing C that transmits output to a rear wheel 14 as a driving wheel.

  The electric motor section A is constituted by an electric motor including a casing 22, a stator 23, a rotor 24, a motor rotation shaft 25, two rolling bearings 40 and 41, and a preload applying structure 70.

  The stator 23 is configured by winding a coil around a magnetic core, and is fixed to the casing 22. In the present embodiment, for convenience of assembly, the casing 22 is divided into three parts in the axial direction, and a casing body 80 having openings at both ends in the axial direction, and an inboard side of the casing body 80 (FIG. 1). An inner cover 81 that closes an opening on the right side) and an outer cover 82 that closes an opening on the outboard side (the left side in FIG. 1) of the casing body 80. The stator 23 is fixed to the inner surface of the casing body 80.

  The rotor 24 is formed of a permanent magnet or the like, and is arranged radially inside the stator 23 with a gap. In the present embodiment, a radial gap type electric motor in which the stator 23 and the rotor 24 face each other with a radial gap therebetween is adopted, but the stator 23 and the rotor 24 face each other with a gap in the axial direction. An axial gap type electric motor may be used.

  A motor rotation shaft 25 is inserted into the inner periphery of the rotor 24. The rotor 24 and the motor rotation shaft 25 are fixed to each other and are configured to rotate integrally. Rolling bearings 40 and 41 are provided at both ends of the motor rotating shaft 25, respectively, and the motor rotating shaft 25 is rotatably supported by the casing 22 by the rolling bearings 40 and 41. In the present embodiment, of the two rolling bearings 40, 41, the rolling bearing 40 on the outboard side (left side in FIG. 1) is provided in the casing body 80, and the rolling bearing 41 on the inboard side (right side in FIG. 1). Are provided on the inner cover 81.

  The preload applying structure 70 includes a wave spring 71 as an elastic member, a protection member 72 that suppresses deterioration of the wave spring 71 due to compression, and an inner cover 81 that houses these. The inner cover 81 is provided with a protection member 72, a wave spring 71, and a cylindrical recess 81 a in which the inboard-side rolling bearing 41 is accommodated. The protection member 72 has an annular ring portion 72a and a cylindrical tube portion 72b that projects in the axial direction from the inner diameter side of the ring portion 72a. The wave spring 71 is a spring member formed by spirally winding a wave-like plate material, and is arranged on the inner periphery of the cylindrical portion 72 b of the protection member 72.

  The ring portion 72a of the protection member 72 is interposed between the wave spring 71 and the outer ring 37 (see FIG. 2) of the inboard-side rolling bearing 41. Since the wave spring 71 is held in the inner cover 81 in a state of being compressed in the axial direction, the wave spring 71 moves the inboard-side rolling bearing 41 in the axial direction via the ring portion 72a (the left side in FIG. 1). To). The ring portion 72a is arranged so as not to come into contact with the inner ring 38, the rolling element 39, and the retainer (not shown) which rotate with the rotation of the motor rotation shaft 25 (so as not to generate sliding resistance). It contacts only the outer ring 37. The axial biasing force (preload) applied to the inboard-side rolling bearing 41 is also applied to the outboard-side rolling bearing 40 via the motor rotation shaft 25. As a result, a preload in the axial direction is applied to the pair of rolling bearings 40 and 41 that support the motor rotation shaft 25, and the vibration of the motor rotation shaft 25 is reduced.

  The outer diameter φK of the wave spring 71 is set so as to effectively apply an axial preload to the outer ring 37 of the rolling bearing 41 and not to apply a shearing force leading to deformation to the ring portion 72a. Desirably, the outer diameter 37 is set smaller than the outer diameter φH of the outer ring 37 and larger than the inner diameter φG of the outer ring 37 (see FIG. 2).

  As shown in FIG. 1, the reduction gear unit B includes a casing 22, an input shaft 27, an intermediate shaft 28, an output shaft 29, and a plurality of rolling bearings that rotatably support these shafts with respect to the casing 22. 42 to 47. The input shaft 27 is integrally and rotatably connected to the motor rotation shaft 25 by spline fitting (including serration fitting). On the other hand, the output shaft 29 is integrally and rotatably connected to a hub wheel 60 constituting a rotation shaft of the wheel bearing portion C by spline fitting (including serration fitting).

  An input gear 30 is provided integrally with the input shaft 27, and an output gear 35 is provided integrally with the output shaft 29. The intermediate shaft 28 is integrally provided with an input-side intermediate gear 31 that meshes with the input gear 30 and an output-side intermediate gear 32 that meshes with the output gear 35. The input gear 30, the input-side intermediate gear 31, the output-side intermediate gear 32, and the output gear 35 are formed by helical gears (external gears). Helical gears are more effective than spur gears in that the number of meshing teeth increases simultaneously and the tooth contact is dispersed, so that noise is quiet and torque fluctuation is small.

  The input shaft 27, the intermediate shaft 28, and the output shaft 29 are arranged in parallel with each other, and the gears provided on these shafts mesh with each other to form a three-shaft, two-stage parallel shaft gear reduction mechanism. The input shaft 27, the intermediate shaft 28, and the output shaft 29 are connected to the respective rolling bearings 42, 44, 46 on the inboard side (the right side in FIG. 1) provided on the casing body 80, and the outer cover 82 provided on the outer cover 82. It is rotatably supported by each rolling bearing 43, 45, 47 on the board side (left side in FIG. 1). As the rolling bearings 42 to 47 for supporting the shafts of the reduction gear unit B and the pair of rolling bearings 40 and 41 for supporting the motor rotating shaft 25, bearings capable of receiving both a radial load and a thrust load, For example, it is preferable to use a deep groove ball bearing.

  As shown in FIG. 1, the wheel bearing portion C is formed of an inner ring rotating type wheel bearing. The wheel bearing portion C is a double-row angular ball bearing mainly including an inner member 61 including a hub wheel 60 and a pair of inner rings 52, an outer ring 53, a plurality of balls 56, and a retainer (not shown). It is. An inner raceway surface 54 is formed on the outer periphery of each inner ring 52. On the other hand, double rows of outer raceway surfaces 55 are formed on the inner periphery of the outer race 53 in correspondence with the inner raceway surfaces 54 of the respective inner races 52. Balls 56 are arranged to be rollable between the inner raceway surface 54 and the outer raceway surface 55 facing each other. The outer ring 53 is fastened and fixed to a mounting portion of the casing 22 (outer cover 82) by bolts or the like.

  A flange portion 60a for mounting a wheel is formed on the outer periphery of the hub wheel 60 on the outboard side. Although not shown, a brake disc and a wheel are mounted on the wheel mounting flange portion 60a. On the other hand, the inner ring 52 is fitted to the small-diameter stepped portion on the inboard side of the hub wheel 60, and the caulked portion 60 b of the hub wheel 60 is pressed against the inner ring 52. The caulked portion 60b is formed by caulking the inboard end of the hub wheel 60 after the inner ring 52 is fitted to the hub wheel 60. The formation of the caulked portion 60b positions the inner ring 52 in the axial direction and applies a preload to the wheel bearing.

  In the in-wheel motor drive device 21 according to the present embodiment, when the motor rotation shaft 25 rotates, the input shaft 27 rotates integrally therewith, and the rotation movement is caused by the input gear 30 having an input side having more teeth than the input gear 30. The speed is reduced by being transmitted to the intermediate gear 31. Then, the rotational motion is further reduced by being transmitted from the output side intermediate gear 32 to the output gear 35 having more teeth.

  As described above, in the in-wheel motor drive device 21 according to the present embodiment, the rotational motion of the motor rotation shaft 25 is reduced in two steps by the reduction mechanism portion B, so that the amplified torque is transmitted to the rear wheel 14. It is possible to use a small electric motor of low torque and high rotation type. For example, when the reduction ratio of the speed reducer unit B is 11, the electric motor can be downsized by using an electric motor that rotates at a high speed of about ten thousand thousands of rotations per minute. As a result, a compact in-wheel motor driving device can be realized, and an electric vehicle having excellent running stability and NVH characteristics while suppressing unsprung weight can be obtained.

  The overall configuration and operation of the in-wheel motor drive device 21 according to the present embodiment are as described above. Next, a point that the present embodiment is excellent in assemblability will be described.

  FIG. 2 is a cross-sectional view showing, on an enlarged scale, a preload applying structure 70 according to the present embodiment and a peripheral portion thereof.

  As shown in FIG. 2, the protection member 72 includes a ring portion 72 a, a cylindrical portion 72 b axially protruding from the outer diameter side of the ring portion 72 a, and an opposite direction to the cylindrical portion 72 b from the inner diameter side of the ring portion 72 a. It has a protruding annular or cylindrical regulating portion 72e. The restricting portion 72e plays a role of restricting the radial movement of the protection member 72 with respect to the rolling bearing 41 by contacting the inner peripheral surface of the outer ring 37 of the rolling bearing 41. The restricting portion 72e is configured to be fixed to the inner peripheral surface of the outer ring 37 by press fitting. Note that the restricting portion 72e may be clearance-fitted to the inner peripheral surface of the outer ring 37.

  Subsequently, a method of assembling the preload applying structure 70 according to the present embodiment will be described.

  In the configuration including the radial gap type electric motor as shown in FIG. 1, there is a situation that it is difficult to perform an assembling operation with the opening of the casing (casing main body 80) turned sideways. In other words, when the casing is turned sideways and the rotor shaft with the rotor is to be inserted horizontally into the inner periphery of the stator, the motor shaft tends to tilt due to gravity. It is difficult to insert the shaft. If the motor rotation shaft is tilted, the stator and the rotor will be attracted by magnetic force, which hinders the assembling work. Therefore, in the configuration including the radial gap type electric motor, as shown in FIG. 3, the rotor 24 and the rolling bearings 40 and 41 are mounted with the opening of the casing main body 80 to which the stator 23 is assembled facing upward. It is desirable to insert the fixed motor rotation shaft 25 vertically. When such an assembling method is adopted, if the protection member 72, the wave spring 71, and the inner cover 81 are to be assembled together on the casing body 80 side, the opening of the inner cover 81 is directed downward. Therefore, there is a problem that the protection member 72 and the wave spring 71 fall off from the concave portion 81a of the inner cover 81.

  Therefore, in the present embodiment, as shown in FIG. 4, the protection member 72 and the wave spring 71 are arranged on the rolling bearing 41 fixed to the motor rotating shaft 25, and the inner cover 81 Is adopted. By employing this method, there is no possibility that the protection member 72 or the wave spring 71 will fall off the inner cover 81.

  Further, according to the configuration according to the present embodiment, when the protection member 72 and the wave spring 71 are arranged on the rolling bearing 41, it is possible to prevent the displacement of the protection member 72 and the wave spring 71. That is, as shown in FIG. 4, by arranging the protection member 72 such that the regulation portion 72 e is inserted into the inner peripheral side of the outer ring 37 of the rolling bearing 41, the outer peripheral surface of the regulation portion 72 e and the outer ring 37 are formed. The radial movement of the protection member 72 with respect to the rolling bearing 41 can be restricted by the interference with the inner peripheral surface. Further, since the wave spring 71 is disposed on the inner periphery of the cylindrical portion 72b of the protection member 72, the radial movement of the wave spring 71 is also restricted by the cylindrical portion 72b.

  As described above, in the present embodiment, since the radial movement of the protection member 72 and the wave spring 71 can be restricted, the protection member 72 and the wave spring 71 are largely displaced on the rolling bearing 41, and It can be prevented from falling from above. For this reason, the work of assembling the inner cover 81 is facilitated, and the workability is improved.

  When the assembling work is performed with the motor rotation shaft 25 being set sideways, the protection member 72 can be pressed into the outer ring 37 so as to prevent the protection member 72 from falling off (separation in the axial direction) from the rolling bearing 41. It is preferable that it is a simple structure. In addition, since the protection member 72 is configured to be press-fittable into the outer ring 37, the protection member 72 and the rolling bearing 41 can be handled as an integrated unit, and the assembling work can be further easily performed. Become. For example, it is also possible to assemble the protection member 72 and the rolling bearing 41 in advance and then assemble the assembly unit to the motor rotation shaft 25.

  When the assembly of the inner cover 81 to the casing body 80 is completed, the wave spring 71 is compressed by the inner cover 81 (see FIG. 2), so that the axial constant pressure of the wave bearing 71 is applied to the rolling bearings 40 and 41. Preload is applied. Further, in this state, the motor rotating shaft 25 is held at a predetermined axial position (the position shown in FIG. 2), and the cylindrical portion 72b of the protection member 72 is spaced from the concave bottom surface 81c of the inner cover 81 by a gap δ. In a non-contact state. However, when the motor rotating shaft 25 receives an axial force due to vibration or the like during traveling of the vehicle and the motor rotating shaft 25 is displaced in the axial direction against the urging force of the wave spring 71, as shown in FIG. The protection member 72 is pushed in the axial direction, and the cylindrical portion 72b contacts the concave bottom surface 81c. At this time, since the cylindrical portion 72b contacts the concave bottom surface 81c before the wave spring 71 is completely compressed in the axial direction, the fatigue caused by the compression of the wave spring 71 is suppressed.

  Generally, in order to effectively suppress the fatigue of the spring member, it is preferable to set the amount of expansion and contraction of the spring member to within 80% of a value obtained by subtracting the contact length from the free length of the spring member. Further, since the amount of expansion and contraction of the wave spring 71 is determined by the axial length T (see FIG. 5) of the cylindrical portion 72b, the free length F and the close contact length U of the spring member are used to adjust the cylindrical portion 72b. The axial length T is preferably set to a value that satisfies the following expression (1).

  T> 0.2 * F + 0.8 * U (1)

  Hereinafter, another embodiment of the present invention will be described.

  In the embodiment shown in FIG. 6, the cylindrical portion 72 b of the protection member 72 is arranged not on the outer periphery of the wave spring 71 but on the inner periphery. Otherwise, the configuration is basically the same as that of the embodiment shown in FIGS. 1 to 5 described above.

  As described above, even when the cylindrical portion 72b is disposed on the inner periphery of the wave spring 71, the radial movement of the wave spring 71 can be restricted by the cylindrical portion 72b. Therefore, similarly to the above-described embodiment, it is possible to prevent the wave spring 71 from being displaced or dropped, and to improve the assembling workability.

  Next, in the embodiment shown in FIG. 7, the restricting portion 72 e is arranged not on the inner peripheral side of the outer ring 37 of the rolling bearing 41 but on the outer peripheral side. Otherwise, the configuration is basically the same as that of the embodiment shown in FIGS. 1 to 5 described above. In this case, since the restricting portion 72e comes into contact with the outer peripheral surface of the outer ring 37, the radial movement of the protective member 72 with respect to the rolling bearing 41 is restricted. Dropping can be prevented, and assembling workability can be improved.

  Further, as shown in FIG. 7, a step portion (small diameter portion) is formed on the outer peripheral surface of the outer ring 37, and the regulating portion 72e is arranged on the step portion, so that the size in the radial direction can be reduced. is there.

  The embodiment shown in FIG. 8 is a combination of the embodiment shown in FIG. 6 and the embodiment shown in FIG. That is, in the present embodiment, the cylindrical portion 72b is arranged on the inner periphery of the wave spring 71, and the restricting portion 72e is arranged on the outer periphery of the outer ring 37. As in the above-described embodiment, also in this embodiment, it is possible to improve the assembling workability.

  In the embodiment shown in FIG. 9, a convex engaging portion 72f not provided in the above-described embodiment is provided on the outer peripheral surface of the regulating portion 72e. When the protection member 72 is disposed on the rolling bearing 41, the engagement member 72 f is engaged with a concave engagement portion provided on the inner peripheral surface of the outer ring 37, so that the protection member 72 for the rolling bearing 41 is formed. In the axial direction can be prevented. In particular, when the assembling operation is performed with the motor rotating shaft 25 being set to the horizontal direction, the presence of the engaging portion 72f is preferable because the protective member 72 can be prevented from falling off the rolling bearing 41. Although the example shown in FIG. 9 has the basic configuration of the protection member 72 shown in FIGS. 1 to 5, each of the other protection members 72 shown in FIGS. 6 to 8 also adopts a configuration in which an engaging portion 72 f is provided. It is possible. Further, the engaging portion 72 may be formed in a concave shape instead of a convex shape.

  The present invention has been described above, but the present invention is not limited to the above embodiment. It goes without saying that the present invention can be embodied in various forms without departing from the gist of the present invention.

  For example, one of the ring portion 72a and the cylindrical portion 72b of the protection member 72 may have a configuration in which it is partially divided in the circumferential direction, such as having an axial slit. Further, instead of the wave spring 71, another spiral or annular spring member such as a coil spring or a wave washer may be used.

  In the above-described embodiment, the preload applying structure 70 is provided only on one of the rolling bearings 41 of the pair of rolling bearings 40 and 41 that support the motor rotating shaft 25. May be provided with a preload applying structure 70 according to the present invention, and an axial preload may be individually applied to both the rolling bearings 40 and 41. Furthermore, the present invention is not limited to the structure for applying a preload to the motor support bearing in the electric motor, but is also applicable to the structure for applying a preload to the support bearing in the speed reducer.

Reference Signs List 21 in-wheel motor drive device 22 casing 23 stator 24 rotor 25 motor rotation shaft 40 rolling bearing 41 rolling bearing 70 preload applying structure 71 wave spring (elastic member)
72 Protective member 72a Ring part 72b Tube part 72e Restriction part 72f Engagement part 81a Recess A Electric motor part B Reduction gear part C Wheel bearing part

Claims (8)

An elastic member that urges a bearing that supports a motor rotation shaft of the electric motor to apply a preload in the axial direction; a protection member that prevents the elastic member from being completely compressed in the axial direction; A casing provided with a recess in which the protection member is accommodated, and a preload applying structure for the motor support bearing,
A ring portion disposed between the elastic member and the bearing; a cylindrical portion protruding in the axial direction from the ring portion and having the elastic member disposed on an outer or inner periphery thereof; And a restricting portion that protrudes from the portion on the opposite side to the cylindrical portion and contacts the inner peripheral surface or the outer peripheral surface of the outer ring of the bearing to restrict the radial movement of the protection member with respect to the bearing. Preloading structure for motor supporting bearings.   2. The preload applying structure for a motor support bearing according to claim 1, wherein the restricting portion is configured to be press fit into an inner circumference or an outer circumference of an outer ring of the bearing. 3.   3. The motor support bearing according to claim 1, wherein the restricting portion is provided with a convex or concave engaging portion that engages with an outer ring of the bearing to prevent the protection member from separating from the bearing in the axial direction. 4. Preload application structure.   4. The preload applying structure for a motor support bearing according to claim 1, wherein an outer diameter of the elastic member is larger than an inner diameter of an outer ring of the bearing. 5.   The preload applying structure for a motor support bearing according to any one of claims 1 to 4, wherein the elastic member is an annular or spiral spring member. A casing, a stator fixed to the casing, a motor rotating shaft, a rotor that rotates integrally with the motor rotating shaft, a bearing that rotatably supports the motor rotating shaft with respect to the casing, and a bearing. An electric motor having a preload applying structure for applying an axial preload to the electric motor,
An electric motor, wherein the preload applying structure according to any one of claims 1 to 5 is used as the preload applying structure.   7. The electric motor according to claim 6, wherein the preload applying structure is provided at both ends of the motor rotation shaft, and individually applies a preload to a pair of bearings supporting the motor rotation shaft. 8. An in-wheel motor drive device including an electric motor unit, a wheel bearing unit, and a speed reducer unit that transmits the rotation of the electric motor unit to the wheel bearing unit by reducing the speed.
An in-wheel motor driving device, wherein the electric motor unit includes the electric motor according to claim 6.