JP2017003048A - Motor drive device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of components, and simply and easily assemble a gear constituting a parallel axis gear reducer.SOLUTION: A in-wheel motor drive device includes a motor A, a speed reduction B formed by a parallel axis gear reducer 39 comprising first-fourth gears 30-33, and a casing 22 housing the motor A and the speed reducer B, and in the in-wheel motor drive device, the first-fourth gears 30-33 of the parallel axis gear reducer 39 are rotatably supported to the casing 22 by rolling bearings 40, 42-46. Among the first-fourth gears 30-33 constituting the parallel axis gear reducer 39, the fourth gear 33 as an output gear is integrated with the rolling bearings 45, 46.SELECTED DRAWING: Figure 1

Description

  The present invention relates to, for example, a vehicle motor drive device that inputs a rotational driving force of an electric motor to a reduction gear unit, decelerates the number of rotations, and transmits it to a wheel side.

  As a conventional vehicle motor drive device, for example, there is an in-wheel motor drive device disclosed in Patent Document 1. The in-wheel motor drive device disclosed in Patent Document 1 includes an electric motor that generates a driving force, a parallel shaft gear reducer that decelerates and outputs the rotation of the electric motor, and outputs from the parallel shaft gear reducer. It consists of a wheel hub that transmits to.

  This in-wheel motor drive device is provided with an intermediate plate between the electric motor and the parallel shaft gear reducer, a motor housing for accommodating the electric motor is provided on the inboard side of the intermediate plate, and an outboard of the intermediate plate The structure which provided the gear housing which accommodates a parallel shaft gear reducer in the side is comprised.

  The electric motor includes a stator fixed to the motor housing and a rotor shaft that is rotatably supported by the motor housing inside the stator. The parallel shaft gear reducer includes a motor input gear coaxially connected to the rotor shaft of the electric motor, a first counter gear that is rotatably supported by the intermediate plate and the gear housing, and meshes with the motor input gear; The second counter gear is supported coaxially with the first counter gear, and the output gear is provided on the axle of the wheel hub and meshes with the second counter gear.

  The gears constituting the parallel shaft gear reducer of the in-wheel motor drive device, for example, the first counter gear and the second counter gear are rotatably supported by the rolling bearings with respect to the intermediate plate and the gear housing. Depending on the structure of the parallel shaft gear reducer, motor input gears and output gears other than the first counter gear and the second counter gear may also be rotatably supported by the rolling bearings with respect to the intermediate plate and the gear housing. There is something.

JP 2014-46742 A

  By the way, as described above, the in-wheel motor drive device disclosed in Patent Document 1 is a parallel shaft gear reduction composed of a plurality of gears including a motor input gear, a first counter gear, a second counter gear, and an output gear. Equipped with a machine. These gears are assembled so as to be rotatably supported by bearings with respect to the intermediate plate and the gear housing.

  In such a parallel shaft gear reducer, when the gear is assembled to the intermediate plate and the gear housing, the inner ring of the bearing is press-fitted into the shaft portion of the gear, and the outer ring of the bearing is attached to the intermediate plate and the gear housing. At this time, in bearings such as deep groove ball bearings where a clearance is provided between the raceway surface of the inner ring or outer ring and the rolling element, the dimensions of each fitting portion are measured during assembly, For the purpose of applying preload or eliminating backlash, axial adjustment by shims is performed.

  However, when the gear is assembled to the intermediate plate and the gear housing, the measurement man-hours until the bearing is assembled and various shims for matching various bearing parts are required, resulting in an increase in the cost of the product. In addition, since the number of parts is large, the sum of tolerances becomes large, and there is a problem that the design of the apparatus becomes complicated.

  Therefore, the present invention has been proposed in view of the above-mentioned problems, and the object of the present invention is to reduce the number of parts for a vehicle that can easily and easily assemble gears constituting a parallel shaft gear reducer. The object is to provide a motor drive device.

  As technical means for achieving the above-mentioned object, the present invention provides a motor part, a reduction gear part constituted by a parallel shaft gear reduction gear comprising a plurality of gears, and a casing containing the motor part and the reduction gear part. And a motor drive device for a vehicle in which each gear of a parallel shaft gear reducer is rotatably supported by a bearing with respect to a casing, and at least one of a plurality of gears constituting the parallel shaft gear reducer The gear is characterized by having an integral structure with the bearing.

  In the vehicle motor drive device of the present invention, since at least one of the plurality of gears constituting the parallel-shaft gear reducer has an integral structure with the bearing, the number of parts can be reduced, so the total sum of tolerances can be reduced. It can be made small, and the design of the apparatus becomes simple. Further, since it is not necessary to measure and select shims until the bearings are assembled, the gears can be assembled easily and easily.

  In the present invention, the bearing integrally formed with the gear includes an inner raceway surface formed on the outer peripheral surface of the shaft portion of the gear, an outer raceway surface formed on the inner peripheral surface of the outer ring fixed to the casing, and the shaft portion. It is desirable that the main part is composed of a rolling element interposed between the inner raceway surface of the outer ring and the outer raceway surface of the outer ring. In this way, an integral structure of the gear and the bearing can be easily realized.

  In the present invention, the bearing integrally formed with the gear includes a double-row angular contact ball bearing structure in which a preload is applied by caulking the shaft end of the gear or by nut tightening at the shaft end of the gear. It is desirable. By adopting such an angular ball bearing structure, it is possible to increase the support rigidity of the bearing and to suppress the generation of abnormal noise and vibration.

  In the present invention, the gear that forms an integral structure with the bearing is an output gear that is coaxially connected to the output shaft of the reduction gear of the parallel shaft gear reducer, and is formed on at least one side of both sides of the output gear. It is desirable to accommodate and assemble the bearing in the formed annular recess. Thus, by housing the bearing in the annular recess of the output gear, the axial width can be reduced in the assembly structure of the gear and the bearing, and the device can be made compact.

  According to the present invention, since at least one of the plurality of gears constituting the parallel shaft gear reducer has an integral structure with the bearing, the number of parts can be reduced, so that the sum of tolerances can be reduced. This simplifies device design. Further, since it is not necessary to measure and select shims until the bearings are assembled, the gears can be assembled easily and easily. As a result, the ease of assembly of the parallel shaft gear reducer can be improved, and a low-cost vehicle motor drive device can be easily realized.

In embodiment of this invention, it is sectional drawing which shows the whole structure of an in-wheel motor drive device. It is the schematic which looked at only the gearwheel which comprises the parallel shaft gear reducer of FIG. 1 from the outboard side. It is an expanded sectional view which shows the 4th gearwheel of the parallel shaft gear reducer of FIG. It is a perspective view which shows the 4th gearwheel of FIG. FIG. 5 is a front view of FIG. 4. In other embodiment of this invention, it is sectional drawing which shows the whole structure of an in-wheel motor drive device. It is an expanded sectional view which shows the 4th gearwheel of the parallel shaft gear reducer of FIG. It is an expanded sectional view showing the modification of the 4th gear of Drawing 7. It is a top view which shows schematic structure of the electric vehicle carrying an in-wheel motor drive device. FIG. 10 is a rear sectional view showing the electric vehicle of FIG. 9. It is sectional drawing which shows the whole structure of the motor drive device for on-board type vehicles.

  An embodiment of an in-wheel motor drive device according to the present invention will be described in detail with reference to the drawings. FIG. 9 is a schematic plan view of the electric vehicle 11 on which the in-wheel motor drive device 21 is mounted, and FIG. 10 is a schematic cross-sectional view of the electric vehicle 11 as viewed from the rear.

  As shown in FIG. 9, 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 drive device 21 that transmits driving force to the rear wheel 14. Equip. As shown in FIG. 10, the rear wheel 14 is accommodated in a wheel housing 15 of the chassis 12 and is fixed to a lower portion of the chassis 12 via a suspension device (suspension) 16.

  The suspension device 16 supports the rear wheel 14 by a suspension arm that extends to the left and right, and suppresses vibration of the chassis 12 by absorbing vibration received by the rear wheel 14 from the ground by a strut including a coil spring and a shock absorber. A stabilizer that suppresses the inclination of the vehicle body during turning or the like is provided at a connecting portion of the left and right suspension arms. The suspension device 16 is an independent suspension type in which the left and right wheels are independently moved up and down in order to improve the followability to the road surface unevenness 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 that drives the left and right rear wheels 14 is provided inside the wheel housing 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 wide cabin space can be secured and the rotation of the left and right rear wheels 14 can be controlled.

  In order to improve the running stability and NVH characteristics of the electric vehicle 11, it is necessary to suppress the unsprung weight, and further, the in-wheel motor drive device 21 is required to be downsized in order to secure a large cabin space.

  Therefore, the in-wheel motor drive device 21 of the embodiment shown in FIG. 1 has the following structure. Thereby, the compact in-wheel motor drive device 21 is implement | achieved and the electric vehicle 11 excellent in driving | running | working stability and NVH characteristic can be obtained by restraining unsprung weight.

  Before describing the characteristic configuration of this embodiment, the overall configuration of the in-wheel motor drive device 21 will be described. In the following description, with the in-wheel motor drive device 21 mounted on the vehicle, the side closer to the outside of the vehicle is referred to as the outboard side (left side in the drawing), and the side closer to the center is referred to as the inboard side (right side in the drawing). Called.

  As shown in FIG. 1, the in-wheel motor drive device 21 includes a motor part A that generates a driving force, a speed reducer part B that decelerates and outputs the rotation of the motor part A, and an output from the speed reducer part B. And a wheel bearing portion C that transmits to a rear wheel 14 (see FIGS. 9 and 10) as a drive wheel. The motor part A and the speed reducer part B are accommodated in the casing 22 and attached in the wheel housing 15 (see FIG. 10) of the electric vehicle 11. The casing 22 is fastened and integrated with bolts in a separable structure including a motor housing of the motor part A and a gear housing of the speed reducer part B.

  The motor unit A is a stator 23 fixed to the casing 22, a rotor 24 disposed so as to face the inner side in the radial direction of the stator 23 with a gap, and a rotor 24 disposed on the inner side in the radial direction of the rotor 24 so as to rotate integrally with the rotor 24 A radial gap type electric motor 26 having a motor rotating shaft 25 is provided. The motor rotating shaft 25 can rotate at a high speed of about 10,000 to 1000 rotations per minute. The stator 23 is configured by winding a coil around the outer periphery of the magnetic core, and the rotor 24 has a permanent magnet or a magnetic body disposed therein.

  The motor rotating shaft 25 has a rotor 24 held by a holder portion 27 that integrally extends radially outward. The holder portion 27 has a configuration in which a concave groove into which the rotor 24 is fitted and fixed is formed in an annular shape. The motor rotating shaft 25 is rotatable with respect to the casing 22 by one end in the axial direction (right side in FIG. 1) on the rolling bearing 28 and the other end in the axial direction (left side in FIG. 1) by the rolling bearing 29. It is supported by.

  The reduction gear unit B includes a first gear 30 that is an input gear, a second gear 31 and a third gear 32 that are intermediate gears, and a fourth gear 33 that is an output gear. The first gear 30 is coaxially attached and fixed to the motor rotating shaft 25 by connecting the shaft portion 34 extending to the inboard side to the motor rotating shaft 25 by spline fitting (including serration fitting; the same applies hereinafter). Has been. The second gear 31 is attached and fixed to the intermediate shaft 35. The third gear 32 is formed integrally with the intermediate shaft 35. The fourth gear 33 is coaxially attached and fixed to the reduction gear output shaft 37 by connecting the shaft portion 36 to the inboard side shaft portion 38 of the reduction gear output shaft 37 by spline fitting.

  The reduction gear portion B decelerates the rotational movement of the motor rotating shaft 25 in two stages by meshing the first gear 30 and the second gear 31 and meshing the third gear 32 and the fourth gear 33. A parallel shaft gear reducer 39 is used.

  The shaft portion 34 of the first gear 30 is rotatably supported with respect to the casing 22 by a rolling bearing 40. The shaft portion 41 of the second gear 31 is supported by the rolling bearing 42 so as to be rotatable with respect to the casing 22. The intermediate shaft 35 to which the second gear 31 is attached and fixed and the third gear 32 is integrally formed is rotatably supported by the casing 22 by rolling bearings 43 and 44. The fourth gear 33 to which the reduction gear output shaft 37 is attached and fixed is rotatably supported with respect to the casing 22 by rolling bearings 45 and 46. The outboard side shaft portion 47 of the reduction gear output shaft 37 is connected to the hub wheel 49 of the wheel bearing portion C by spline fitting, and the output of the reduction gear portion B is connected to the rear wheel 14 (see FIGS. 9 and 10). introduce.

  The 1st gearwheel 30-the 4th gearwheel 33, and the rotating shaft of each gearwheel are demonstrated based on FIG. FIG. 2 is a schematic view of only the first gear 30 to the fourth gear 33 constituting the parallel shaft gear reducer 39 of FIG. 1 as viewed from the outboard side.

  The first gear 30 is attached and fixed to the motor rotation shaft 25 (see FIG. 1), and rotates about its axis C1. The second gear 31 is attached and fixed to the intermediate shaft 35 (see FIG. 1), and the third gear 32 is formed integrally with the intermediate shaft 35 and rotates about its axis C2. The fourth gear 33 is fixedly attached to the speed reducer output shaft 37 (see FIG. 1), and rotates around its axis C3. In addition, since the motor rotating shaft 25 and the reduction gear output shaft 37 are arrange | positioned coaxially, each axial center C1 and axial center C3 correspond.

  In this embodiment, the shaft centers C1, C2, and C3 of the motor rotating shaft 25, the intermediate shaft 35, and the speed reducer output shaft 37 are arranged on a straight line EE, so that the speed reducer portion B is made compact in the radial direction. ing. However, the arrangement of the shaft centers C1, C2, and C3 is not limited to the arrangement as in this embodiment, and is appropriately shifted in consideration of the space of the casing 22 while maintaining the meshing of the gears 30 to 33. May be.

  Here, helical gears are used for the first gear 30 to the fourth gear 33 constituting the parallel shaft gear reducer 39. Helical gears are effective in that the number of teeth engaged simultaneously increases and the tooth contact is dispersed, so that the sound is quiet and torque fluctuation is small. In consideration of the meshing ratio of gears and the limit number of rotations, the number of modules is preferably about 1 to 3.

  Since the in-wheel motor drive device 21 is housed in the wheel housing 15 (see FIG. 10) and becomes an unsprung load, it is essential to reduce the size and weight. The electric motor 26 can be miniaturized by combining the parallel shaft gear reducer 39 with the electric motor 26. For example, when the parallel shaft gear reducer 39 having a reduction ratio of 11 is used, the electric motor 26 can be reduced in size by using the electric motor 26 that rotates at a high speed of about ten thousand rotations per minute. In this case, considering the space of the casing 22 and the like, the reduction ratio of the first stage consisting of the first gear 30 and the second gear 31 is about 2 to 4, and the second stage consisting of the third gear 32 and the fourth gear 33. The reduction ratio is preferably about 3 to 5.

  As shown in FIG. 1, the wheel bearing portion C includes a wheel bearing 48 having the following structure. The wheel bearing 48 is disposed on the outer side of the hub wheel 49 and the inner ring 50, the hub wheel 49 connected to the reducer output shaft 37 so as to transmit torque, the inner ring 50 fitted to the outer periphery of the hub wheel 49, and the outer ring 50. This is a double-row angular contact ball bearing including an outer ring 51, a plurality of balls 52 disposed between the hub ring 49 and the inner ring 50 and the outer ring 51, and a cage 53 that holds the plurality of balls 52. Seal members 54 are provided at both ends in the axial direction of the wheel bearing 48 to prevent intrusion of muddy water and the like and leakage of grease.

  The wheel bearing 48 is fastened and fixed to the parallel shaft gear reducer 39 by screwing a nut 55 into a male screw portion formed at an end of the outboard side shaft portion 47 of the reducer output shaft 37. . The outer ring 51 of the wheel bearing 48 is attached and fixed to the casing 22. The inner ring 50 of the wheel bearing 48 is prevented from coming off by coming into contact with the flange portion 56 of the reduction gear output shaft 37. The rear wheel 14 (see FIGS. 9 and 10) is connected to the hub wheel 49 of the wheel bearing 48 by a hub bolt 57.

  The overall configuration of the in-wheel motor drive device 21 in this embodiment is as described above, and the characteristic configuration will be described in detail below.

  In the in-wheel motor drive device 21, at least one of the plurality of gears constituting the parallel shaft gear reducer 39 has an integral structure with the bearing. In this embodiment, as shown in FIGS. 1 and 3, among the first to fourth gears 30 to 33 constituting the parallel shaft gear reducer 39, the fourth gear 33 has an integral structure with the rolling bearings 45 and 46. Eggplant. In the following embodiment, the fourth gear 33 and the rolling bearings 45 and 46 will be described. However, the present invention is not limited to this, and the other first to third gears 30 to 32 and the rolling bearing 40, It is applicable also to 42-44.

  Since the fourth gear 33 is an output gear that becomes high torque after deceleration in the parallel shaft gear reducer 39, it has a larger diameter than the other first to third gears 30 to 32 in order to ensure the strength of the teeth. The gear has a large axial width. The fourth gear 33 connects the shaft portion 36 that engages with the inboard side shaft portion 38 of the reduction gear output shaft 37, the tooth portion 58 that meshes with the third gear 32, and the shaft portion 36 and the tooth portion 58. It is composed of a neck portion 59. Thus, by connecting the shaft portion 36 and the tooth portion 58 with the neck portion 59 having a small axial width, the annular recess 60 having a space surrounded by the shaft portion 36, the neck portion 59 and the tooth portion 58 becomes the fourth gear. 33 on both sides.

  The rolling bearings 45 and 46 are accommodated and assembled in the annular recess 60 of the fourth gear 33. Thus, by accommodating the rolling bearings 45 and 46 in the annular recess 60 of the fourth gear 33, as shown in FIGS. 4 and 5, in the assembly structure of the fourth gear 33 and the rolling bearings 45 and 46, the shaft The width in the direction can be reduced, the protrusion of the rolling bearings 45 and 46 to the outside in the axial direction can be suppressed, and the in-wheel motor drive device 21 can be made compact.

  The rolling bearings 45 and 46 integrally formed with the fourth gear 33 are configured by a shaft portion 36 of the fourth gear 33, an inner ring 61, an outer ring 62, rolling elements 63 and 64, and a cage (not shown). Since one rolling bearing 45 located on the inboard side of the fourth gear 33 and the other rolling bearing 46 located on the outboard side have the same structure arranged symmetrically, each component Are given the same reference numerals.

  As shown in FIG. 3, the shaft portion 36 of the fourth gear 33 has one inner raceway surface 65 formed on the outer peripheral surface thereof. The inner ring 61 is press-fitted into the small diameter step portion 66 of the shaft portion 36 of the fourth gear 33. A double row raceway surface 65, 67 is configured by one inner raceway surface 65 formed on the outer peripheral surface of the shaft portion 36 of the fourth gear 33 and the other inner raceway surface 67 formed on the outer peripheral surface of the inner ring 61. To do.

  The end portion of the small-diameter step portion 66 of the shaft portion 36 into which the inner ring 61 is press-fitted is swaged outward by swing caulking, and the inner ring 61 is prevented from being detached by the swaged portion 68 and integrated with the shaft portion 36, A preload is applied to the rolling bearings 45 and 46. The outer ring 62 is fixed to the casing 22. Double rows of outer raceway surfaces 69 and 70 facing the inner raceway surfaces 65 and 67 of the shaft portion 36 and the inner race 61 are formed on the inner circumferential surface of the outer race 62.

  The rolling bearings 45 and 46 including the shaft portion 36, the inner ring 61, and the outer ring 62 are formed on the inner raceway surfaces 65 and 67 formed on the outer peripheral surfaces of the shaft portion 36 and the inner ring 61 and the inner peripheral surface of the outer ring 62. Rolling elements 63 and 64 are interposed between the outer raceway surfaces 69 and 70, and the double-row angular balls in which the rolling elements 63 and 64 in each row are supported at equal intervals in the circumferential direction by a cage (not shown). It has a bearing structure.

  As described above, by adopting the angular ball bearing structure to which the preload is applied, the support rigidity of the rolling bearings 45 and 46 can be increased, and the generation of abnormal noise and vibration can be suppressed. In addition, although this embodiment demonstrates the double-row angular contact ball bearing structure, this invention is not limited to this, A single-row angular contact ball bearing structure may be sufficient.

  In this in-wheel motor drive device 21, among the first to fourth gears 30 to 33 constituting the parallel shaft gear reducer 39, the fourth gear 33 forms an integral structure with the rolling bearings 45 and 46, so the number of parts is reduced. Therefore, the sum of tolerances can be reduced, and the design of the in-wheel motor drive device 21 is simplified. In addition, since measurement and shim selection until the rolling bearings 45 and 46 are assembled are not required, the fourth gear 33 can be assembled easily and easily.

  As described above, the rolling bearings 45 and 46 include the shaft portion 36 of the fourth gear 33 and the inner raceway surfaces 65 and 67 of the inner ring 61, the outer raceway surfaces 69 and 70 of the inner peripheral surface of the outer ring 62, the shaft portion 36 and A main part is constituted by the rolling elements 63 and 64 interposed between the inner raceway surfaces 65 and 67 of the inner ring 61 and the outer raceway surfaces 69 and 70 of the outer ring 62. Thereby, the integral structure of the 4th gearwheel 33 and the rolling bearings 45 and 46 is easily realizable. Further, the ease of assembly of the parallel shaft gear reducer 39 can be improved, and the low-cost in-wheel motor drive device 21 can be easily realized.

  In the above embodiment, the dual-support structure in which the fourth gear 33 is supported by both the inboard side rolling bearing 45 and the outboard side rolling bearing 46 has been described, but the structure shown in FIGS. 6 and 7 is used. There may be. 6 and 7, the same parts as those in FIGS. 1 and 3 are denoted by the same reference numerals, and redundant description is omitted.

  That is, when the rigidity in the fitting structure between the shaft portion 36 of the fourth gear 33 and the inboard side shaft portion 38 of the reduction gear output shaft 37 can be ensured, as shown in FIGS. The fourth gear 33 may be a cantilever structure in which the outboard side rolling bearing 46 is omitted and only the inboard side rolling bearing 45 is supported.

  In the embodiment shown in FIG. 7, the inner ring 61 is press-fitted into the small-diameter step portion 66 of the shaft portion 36 of the fourth gear 33, and the end portion of the small-diameter step portion 66 is crimped outward by swing caulking. The rolling bearing 45 having a crimping structure in which the inner ring 61 is prevented from coming off with the crimping portion 68 and integrated with the shaft portion 36 has been described. However, the rolling bearing 45 may have a nut tightening structure as shown in FIG. . In FIG. 8, the same parts as those in FIG.

  That is, as shown in FIG. 8, a male screw portion 71 is formed on the outer peripheral surface of the small diameter step portion 66 of the shaft portion 36 of the fourth gear 33, and a nut 72 is screwed to the male screw portion 71, and tightening by the nut 72 is performed. Therefore, the inner ring 61 may be prevented from coming off and integrated with the shaft portion 36, and a nut tightening structure for applying a preload to the rolling bearing 45 may be employed.

  This nut tightening structure is a case where the fourth gear 33 is applied to a cantilever structure that supports only the rolling bearing 45 on the inboard side. However, the structure shown in FIG. The present invention can also be applied to a double-supported structure that is supported by both the side rolling bearing 45 and the outboard side rolling bearing 46.

  Finally, the overall operation principle of the in-wheel motor drive device 21 in this embodiment will be described.

  As shown in FIG. 1, in the motor part A, for example, the rotor 24 rotates by receiving electromagnetic force generated by supplying an alternating current to the stator 23. Thereby, in the speed reducer part B, the rotation of the motor rotating shaft 25 is decelerated by the first gear 30, the second gear 31, the third gear 32 and the fourth gear 33 that constitute the parallel shaft gear speed reducer 39. It is transmitted to the wheel bearing portion C via the machine output shaft 37. At this time, since the rotation of the motor rotating shaft 25 is decelerated by the reducer part B and transmitted to the reducer output shaft 37, even when the low torque, high speed rotating type electric motor 26 is employed in the motor part A, It is possible to transmit the necessary torque to the rear wheel 14 (see FIGS. 9 and 10).

  The reduction ratio of the reduction gear section B is 1 / 2.5 at the first stage of the first gear 30 and the second gear 31 and 1 / 4.5 at the second stage of the third gear 32 and the fourth gear 33. For example, the reduction ratio can be as large as about 1/11. Thus, by adopting the parallel shaft gear reducer 39 capable of obtaining a large reduction ratio, a compact and high reduction ratio in-wheel motor drive device 21 can be obtained. Further, since the parallel shaft gear reducer 39 uses a helical gear, it is easy to manufacture, the cost can be reduced, and the in-wheel motor drive device 21 that is quiet and efficient in terms of performance is realized. Can do.

  In this embodiment, the radial gap type electric motor 26 is exemplified as the motor portion A, but a motor having an arbitrary configuration is applicable. For example, an axial gap type electric motor including a stator fixed to a casing and a rotor arranged so as to face the inner side in the axial direction of the stator with a gap may be used.

  The description of the operation in this embodiment has been made by paying attention to the rotation of each member, but in reality, power including torque is transmitted from the motor part A to the rear wheel 14. Therefore, the power decelerated as described above is converted to high torque. Also, the case where power is supplied to the motor unit A to drive the motor unit and the power from the motor unit A is transmitted to the rear wheels 14 is shown. On the contrary, the vehicle decelerates or goes down the hill. In such a case, the power from the rear wheel 14 side may be converted into high-rotation low-torque rotation by the reduction gear part B and transmitted to the motor part A, and the motor part A may generate power. Furthermore, the electric power generated here may be stored in a battery and used later for driving the motor unit A or for operating other electric devices provided in the vehicle.

  In the above embodiment, the vehicle motor drive device in which the in-wheel motor drive device 21 for driving the left and right rear wheels 14 is provided inside the wheel housing 15 (see FIG. 10) has been described. However, the present invention is not limited to this, and can also be applied to a vehicle motor drive device 81 called an on-board type shown in FIG. In FIG. 11, the same parts as those in FIG.

  As shown in FIG. 11, the on-board type vehicle motor drive device 81 drives the rear wheel 14 via left and right drive shafts 82. The vehicle motor drive device 81 includes a reduction part B having a parallel shaft gear reducer 39 and a motor part A that rotationally drives the reduction part B. The vehicle motor drive device 81 includes two motor units A and two deceleration units B on the left and right.

  The two motor parts A are coaxially arranged adjacent to each other back to back. Further, the speed reduction part B is arranged coaxially with the motor part A. The drive shaft 82 mainly includes a fixed type constant velocity universal joint 83 on the rear wheel 14 side, a sliding type constant velocity universal joint 84 on the speed reducer side, and an intermediate shaft 85 that connects between the two constant velocity universal joints 83, 84. The configuration. The speed reducer output shaft 37 is connected to the sliding type constant velocity universal joint 84 by spline fitting, and transmits the output of the speed reducing portion B to the rear wheel 14.

  In the above embodiment, as illustrated in FIGS. 9 and 10, the electric vehicle 11 having the rear wheel 14 as a drive wheel is illustrated, but the front wheel 13 may be a drive wheel or a four-wheel drive vehicle. . In the present specification, “electric vehicle” is a concept including all vehicles that obtain driving force from electric power, and includes, for example, a hybrid vehicle.

  The present invention is not limited to the above-described embodiments, and can of course be implemented in various forms without departing from the gist of the present invention. It includes the equivalent meanings recited in the claims and the equivalents recited in the claims, and all modifications within the scope.

DESCRIPTION OF SYMBOLS 21 In-wheel motor drive device 22 Casing 30-33 Gear 36 Shaft part 39 Parallel shaft gear reducer 45,46 Bearing 60 Annular recessed part 62 Outer ring 63,64 Rolling element 65,67 Inner raceway surface 68 Clamping part 69,70 Outer raceway Surface 72 Nut A Motor part B Reducer part C Wheel bearing part

Claims (4)

A motor unit, a speed reducer unit composed of a parallel shaft gear reducer composed of a plurality of gears, and a casing that houses the motor unit and the speed reducer unit, wherein each gear of the parallel shaft gear reducer is a casing A vehicle motor drive device that is rotatably supported by a bearing,
The vehicle motor drive device according to claim 1, wherein at least one of the plurality of gears constituting the parallel shaft gear reducer has an integral structure with the bearing.   The bearing integrally formed with the gear includes an inner raceway surface formed on the outer peripheral surface of the shaft portion of the gear, an outer raceway surface formed on the inner peripheral surface of the outer ring fixed to the casing, and the shaft portion. The vehicle motor drive device according to claim 1, wherein a main part is configured by a rolling element interposed between an inner raceway surface and an outer raceway surface of the outer ring.   The bearing having an integral structure with the gear includes a double-row angular ball bearing structure in which preload is applied by caulking the shaft end portion of the gear or nut tightening at the shaft end portion of the gear. Or the motor drive unit for vehicles of 2.   The gear that forms an integral structure with the bearing is an output gear that is coaxially connected to a reduction gear output shaft of a parallel-shaft gear reduction gear, and is formed on at least one side of both sides of the output gear. The vehicle motor drive device according to any one of claims 1 to 3, wherein the bearing is housed and assembled in an annular recess.

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