JP2017032006A - In-wheel motor drive unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the assembling performance of a wheel bearing with respect to a parallel-shaft gear reduction gear, and to manage a preload at the wheel bearing.SOLUTION: An in-wheel motor drive unit 21 has a motor part A, a reduction gear part B which is constituted of a parallel shaft gear reduction gear 38, and a wheel bearing part C which is constituted of a wheel bearing 43. The parallel shaft gear reduction gear 38 comprises a fourth gear 33 which transmits a drive force to the wheel bearing 43. The wheel bearing 43 comprises an outer ring 46 in which a double-row outside raceway surface is formed at an internal peripheral face; a hub ring 48 and an inner ring 50 in which inside raceway surfaces opposing the outside raceway surface are formed at external peripheral faces; and double-row rolling bodies 51 which are interposed between the outside raceway surface of the outer ring 46 and the inside raceway surfaces of the hub ring 48 and the inner ring 50. The inner ring 50 of the wheel bearing 43 is integrally formed with an inboard-side shaft part 55 which supports the fourth gear 33 of the parallel shaft gear reduction gear 38.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an in-wheel motor drive device in which, for example, an output shaft of an electric motor and a wheel bearing are connected via a reduction gear.

  A conventional in-wheel motor drive device has a structure disclosed in Patent Document 1, for example. 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.

JP 2014-46742 A

  By the way, in the in-wheel motor drive device disclosed by patent document 1, the output from a parallel shaft gear reducer is made into a wheel hub by connecting a wheel hub and the output gear of a parallel shaft gear reducer so that torque transmission is possible. I try to communicate.

  Thus, in order to couple the wheel hub and the output gear of the parallel shaft gear reducer so that torque can be transmitted, the following structure is required. For example, there is a structure in which a shaft member for connecting the wheel hub and the output gear of the parallel shaft gear reducer is provided separately from the wheel hub and the output gear of the parallel shaft gear reducer.

  In this structure, the wheel hub is coupled to one end portion of the shaft member by spline fitting, and the output gear of the parallel shaft gear reducer is coupled to the other end portion of the shaft member by spline fitting. . Moreover, it can also be set as the structure fitted with a wheel hub by integrating a reduction gear output gear and a shaft member, and giving the spline shape to the edge part.

  As described above, in a structure using a shaft member separate from the output gear of the wheel hub or parallel shaft gear reducer, or a structure in which the output gear and the shaft member are integrated, the wheel hub is assembled to the shaft member. The work is complicated, and it is difficult to improve the assembly of the wheel hub to the parallel shaft gear reducer.

  In order to eliminate rattling in the wheel hub and to improve the rigidity against the wheel hub's shaft inclination, when applying preload to the wheel hub bearing, after fitting the shaft member and the wheel hub described above, nuts etc. There is also a problem that it is necessary to apply an axial force and manage an appropriate preload, and a complicated management man-hour is required.

  Therefore, the present invention has been proposed in view of the above-mentioned problems, and the object of the present invention is to improve the assemblability of the wheel hub with respect to the parallel shaft gear reducer and to enable preload management at the wheel hub. An in-wheel motor drive device is provided.

  As technical means for achieving the above-mentioned object, the present invention includes a motor unit, a speed reducer unit configured by a parallel shaft gear reducer, and a wheel bearing unit configured by a wheel bearing. The in-wheel motor drive device, the parallel shaft gear reducer has an output gear that transmits driving force to the wheel bearing, and the wheel bearing has a double row outer raceway formed on the inner peripheral surface A double row interposed between the outer race, the hub race and the inner race having an outer race surface formed with an inner race surface facing the outer race track surface, and the outer race surface of the outer race and the inner race track surface of the hub race and the inner race. And an inner ring of the wheel bearing has a configuration in which a shaft portion that supports the output gear of the parallel shaft gear reducer is integrally formed.

  In the in-wheel motor drive device of the present invention, the inner ring of the wheel bearing has a configuration in which the shaft portion that supports the output gear of the parallel shaft gear reducer is integrally formed. There is no need to provide a shaft member separate from the output gear of the reduction gear.

  As a result, the work of assembling the wheel bearing to the output gear of the parallel shaft gear reducer is simplified, and the ease of assembling the wheel bearing to the parallel shaft gear reducer is facilitated. In addition, when applying a preload to the wheel bearing, it is possible to manage an appropriate preload prior to assembly, thereby reducing the number of management steps.

  In the present invention, it is desirable that the shaft portion of the inner ring and the output gear of the parallel shaft gear reducer are integrally formed. Thus, if the shaft portion of the inner ring and the output gear of the parallel shaft gear reducer are integrally formed, the work of assembling the wheel bearing to the parallel shaft gear reducer is further simplified, and the parallel shaft gear reducer Assembling performance of the wheel bearing can be further improved.

  The inner ring in the present invention is preferably configured to be fitted to the hub ring so as to be able to transmit torque. As described above, the configuration in which the inner ring is fitted to the hub wheel so as to be able to transmit torque enables the output from the output gear of the parallel shaft gear reducer to be transmitted to the wheel via the wheel bearing.

  In the present invention, it is desirable to fix the inner ring and the hub ring by caulking or nut tightening. Thus, if the inner ring and the hub ring are fixed by caulking or nut tightening, the assembly can be simplified as a wheel bearing to which a preload is applied by caulking or nut tightening.

  According to the present invention, it is not necessary to provide a shaft member separate from the wheel bearing or the output gear of the parallel shaft gear reducer. Therefore, the work of assembling the wheel bearing to the output gear of the parallel shaft gear reducer is simplified, and the ease of assembling the wheel bearing to the parallel shaft gear reducer is facilitated. In addition, when applying a preload to the wheel bearing, it is possible to manage an appropriate preload prior to assembly, thereby reducing the number of management steps.

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 a principal part expanded sectional view which shows the wheel bearing and axial part of FIG. In other embodiment of this invention, it is sectional drawing which shows the whole structure of an in-wheel motor drive device. It is a principal part expanded sectional view which shows the wheel bearing and output gear of FIG. In other embodiment of this invention, it is sectional drawing which shows the whole structure of an in-wheel motor drive device. It is a principal part expanded sectional view which shows the wheel bearing and output gear of FIG. In other embodiment of this invention, it is sectional drawing which shows the whole structure of an in-wheel motor drive device. It is a principal part expanded sectional view which shows the wheel bearing and output gear of FIG. It is a top view which shows schematic structure of the electric vehicle carrying an in-wheel motor drive device. It is back sectional drawing which shows the electric vehicle of FIG.

  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. 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 cross-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 drive wheel, and an in-wheel motor drive device 21 that transmits driving force to the rear wheel 14. Equip. As shown in FIG. 11, the rear wheel 14 is accommodated in a wheel housing 15 of the chassis 12 and fixed to the 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. A wheel bearing portion C that transmits to a rear wheel 14 (see FIGS. 10 and 11) as a drive wheel is provided. 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. 11) 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 coaxially attached and fixed to the intermediate shaft 36 by connecting the shaft portion 35 to the intermediate shaft 36 by spline fitting. The third gear 32 is formed integrally with the aforementioned intermediate shaft 36. The fourth gear 33 has a shaft portion 37 connected to an inboard side shaft portion 55 integrally extending from an inner ring 50 of a wheel bearing 43 described later by spline fitting, whereby the inboard side shaft portion 55 of the inner ring 50 is connected. It is fixed coaxially.

  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 38 is used.

  The shaft portion 34 of the first gear 30 is rotatably supported with respect to the casing 22 by a rolling bearing 39. The shaft portion 35 of the second gear 31 is supported by the rolling bearing 40 so as to be rotatable with respect to the casing 22. The intermediate shaft 36 on 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 41 and 42.

  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 38 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 36 (see FIG. 1), and the third gear 32 is formed integrally with the intermediate shaft 36 and rotates about its axis C2. The fourth gear 33 is attached and fixed to the inboard side shaft portion 55 (see FIG. 1) of the inner ring 50, and rotates about its axis C3. Since the shaft portion 34 of the first gear 30 and the shaft portion 37 of the fourth gear 33 are arranged on the same axis, the respective shaft centers C1 and C3 coincide with each other.

  In this embodiment, the shaft centers C1, C2, and C3 of the inboard side shaft portion 55 of the motor rotation shaft 25, the intermediate shaft 36, and the inner ring 50 are arranged on a straight line EE, and the radial direction of the reduction gear portion B is set. We are trying to make it compact. 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 38. 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 inside the wheel housing 15 (see FIG. 11) and becomes an unsprung load, a reduction in size and weight is essential. The electric motor 26 can be downsized by combining the parallel shaft gear reducer 38 with the electric motor 26.

  For example, when the parallel shaft gear reducer 38 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 is composed of a wheel bearing 43 having the following structure.

  The wheel bearing 43 has an outer ring 46 in which double-row outer raceways 44 and 45 (see FIG. 3) are formed on the inner circumferential surface, and one inner raceway 47 (see FIG. 3) in the outer circumferential surface. The hub wheel 48, the inner ring 50 having the other inner raceway surface 49 (see FIG. 3) formed on the outer peripheral surface, the inner raceway surfaces 47, 49 of the hub wheel 48 and the inner ring 50, and the outer raceway surfaces 44, 45 of the outer ring 46. Are provided with a plurality of rolling elements 51 and a retainer 52 for holding the plurality of rolling elements 51. The inner raceway surface 47 of the hub ring 48 and the inner raceway surface 49 of the inner ring 50 constitute a double row inner raceway surface facing the outer raceway surfaces 44 and 45 of the outer ring 46.

  Seal members 53 are provided at both ends of the wheel bearing 43 in the axial direction in order to prevent intrusion of muddy water or lubricating oil and leakage of grease sealed in the bearing. Further, the outer ring 46 of the wheel bearing 43 is fixedly attached to the casing 22. Further, the rear wheel 14 (see FIGS. 10 and 11) is connected to the hub wheel 48 of the wheel bearing 43 by the hub bolt 54.

  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 of the embodiment shown in FIG. 1, as shown in FIG. 3, the inner ring 50 of the wheel bearing 43 is an inboard side shaft portion that supports the fourth gear 33 of the parallel shaft gear reducer 38. 55 is integrally formed. Further, the inner ring 50 is integrally formed with an outboard side shaft portion 56 that is fitted to the hub wheel 48 so as to be able to transmit torque.

  By connecting the inboard side shaft portion 55 of the inner ring 50 and the shaft portion 37 of the fourth gear 33 by spline fitting, the inboard side shaft portion 55 of the inner ring 50 is coaxially connected to the shaft portion 37 of the fourth gear 33. Installation is fixed. Further, the outboard side shaft portion 56 of the inner ring 50 is press-fitted into the shaft hole 57 of the hub wheel 48 and is spline-fitted, thereby connecting the outboard side shaft portion 56 of the inner ring 50 to the hub wheel 48 so that torque can be transmitted. ing. Thus, the output of the parallel shaft gear reducer 38 is transmitted to the rear wheel 14 (see FIGS. 10 and 11) via the wheel bearing 43.

  The end of the outboard side shaft portion 56 of the inner ring 50 is caulked outward in the radial direction, and a preload is applied to the wheel bearing 43 by the caulking portion 58. By applying this preload, the wheel bearing 43 has a double-row angular ball bearing structure. Moreover, the assembly of the wheel bearing 43 can be simplified by applying the preload. Since the inner ring 50 of the wheel bearing 43 has the above-described structure, the wheel bearing 43 and the fourth gear 33 of the parallel shaft gear reducer 38 are connected.

  In the in-wheel motor drive device 21, the inner ring 50 of the wheel bearing 43 has a configuration in which an inboard side shaft portion 55 that supports the fourth gear 33 of the parallel shaft gear reducer 38 is integrally formed. There is no need to provide a separate shaft member from the wheel bearing 43 or the fourth gear 33 of the parallel shaft gear reducer 38.

  As a result, the work of assembling the wheel bearing 43 to the fourth gear 33 of the parallel shaft gear reducer 38 is simplified, and the ease of assembling the wheel bearing 43 to the parallel shaft gear reducer 38 can be improved. Become. In addition, when applying a preload to the wheel bearing 43, it is possible to manage an appropriate preload prior to assembly, thereby reducing management man-hours.

  In the embodiment of FIGS. 1 and 3, the structure in which the inboard side shaft portion 55 that supports the fourth gear 33 is integrally formed on the inner ring 50 of the wheel bearing 43 has been described, but the present invention is not limited thereto. Instead, the structure shown in FIGS. 4 and 5 may be used. 4 and 5, the same parts as those in FIGS. 1 and 3 are denoted by the same reference numerals, and redundant description is omitted.

  In the in-wheel motor drive device 21 of the embodiment shown in FIG. 4, as shown in FIG. 5, the shaft portion 37 of the fourth gear 33 of the parallel shaft gear reducer 38 is integrated with the inboard side shaft portion 55 of the inner ring 50. Is formed. As described above, by integrally forming the inboard side shaft portion 55 of the inner ring 50 and the fourth gear 33 of the parallel shaft gear reducer 38, an operation of assembling the wheel bearing 43 to the parallel shaft gear reducer 38 can be performed. This further simplifies the assembly of the wheel bearing 43 with respect to the parallel shaft gear reducer 38.

  In the embodiment shown in FIGS. 1 and 3 and the embodiment shown in FIGS. 4 and 5, the case where the inboard side shaft portion 55 of the inner ring 50 of the wheel bearing 43 has a solid structure has been described. Without being limited to this, as shown in FIGS. 6 and 7, the inboard side shaft portion 55 of the inner ring 50 may have a hollow structure. 6 and 7, the same parts as those in FIGS. 4 and 5 are denoted by the same reference numerals, and the duplicate description is omitted.

  In the in-wheel motor drive device 21 of the embodiment shown in FIG. 6, as shown in FIG. 7, the shaft portion 37 of the fourth gear 33 of the parallel shaft gear reducer 38 is integrated with the inboard side shaft portion 55 of the inner ring 50. Is formed. The inboard side shaft portion 55 of the inner ring 50 and the shaft portion 37 of the fourth gear 33 are hollow. On the other hand, the hub wheel 48 has a hollow shaft-shaped small-diameter step portion 59 extending toward the inboard side. The inboard side shaft portion 55 of the inner ring 50 and the shaft portion 37 of the fourth gear 33 are press-fitted into the small-diameter step portion 59 of the hub wheel 48 and connected so as to transmit torque by spline fitting.

  Further, the end portion of the small diameter step portion 59 of the hub wheel 48 is caulked outward in the radial direction, and the preload is applied to the wheel bearing 43 by the caulking portion 60. By applying this preload, the wheel bearing 43 has a double-row angular ball bearing structure. Moreover, the assembly of the wheel bearing 43 can be simplified by applying the preload. Since the hub wheel 48 of the wheel bearing 43 has the above-described structure, the wheel bearing 43 is fixed to the fourth gear 33 of the parallel shaft gear reducer 38.

  In this caulking structure, a concave portion 61 is formed on the inboard side end surface of the fourth gear 33, and the caulking portion 60 is accommodated in the concave portion 61. Thereby, the caulking portion 60 does not protrude from the end face on the inboard side of the fourth gear 33, and interference with other peripheral parts can be avoided, and the parallel shaft gear reducer 38 can be made compact. .

  In the embodiment shown in FIGS. 6 and 7, the wheel bearing 43 and the fourth gear 33 of the parallel shaft gear reducer 38 are fixed with a structure in which the end of the small diameter step portion 59 of the hub wheel 48 is caulked. Although described, this invention is not limited to this, The structure shown in FIG. 8 and FIG. 9 may be sufficient. 8 and 9, the same parts as those in FIGS. 6 and 7 are denoted by the same reference numerals, and the duplicate description is omitted.

  In the in-wheel motor drive device of the embodiment shown in FIG. 8, as shown in FIG. 9, a male screw part 62 is formed on the outer peripheral surface of the end of the small diameter step part 59 of the hub wheel 48, and a nut 63 is provided on the male screw part 62. Screw together. A preload is applied to the wheel bearing 43 by tightening the nut. By applying this preload, the wheel bearing 43 has a double-row angular ball bearing structure. Moreover, the assembly of the wheel bearing 43 can be simplified by applying the preload. By such nut tightening, the wheel bearing 43 is fixed to the fourth gear 33 of the parallel shaft gear reducer 38.

  In this nut tightening structure, a recess 61 is formed on the end face of the fourth gear 33 on the inboard side, and the male screw portion 62 and the nut 63 are accommodated in the recess 61. Thereby, the male screw part 62 and the nut 63 do not protrude from the end face on the inboard side of the fourth gear 33, and interference with other peripheral parts can be avoided, and the parallel shaft gear reducer 38 can be made compact. Can be planned.

  In the embodiment shown in FIGS. 6 to 9, the small diameter step portion 59 of the hub wheel 48 is connected to the inboard side shaft portion 55 of the inner ring 50 and the shaft portion 37 of the fourth gear 33. The male spline is formed on the outer peripheral surface of 59, and the female spline is formed on the inner peripheral surface of the inboard side shaft portion 55 of the inner ring 50 and the shaft portion 37 of the fourth gear 33.

  In addition to this spline fitting structure, since the small diameter step portion 59 of the hub wheel 48 is hollow, the outer peripheral surface of the small diameter step portion 59 of the hub wheel 48 or the inboard side shaft portion 55 of the inner ring 50 and the The inner peripheral surface of the shaft portion 37 of the four gears 33 is knurled, and the small-diameter step portion 59 of the hub wheel 48 is expanded by a jig to perform plastic deformation and elastic deformation such as expansion caulking that connects the two. Other connected structures may be used.

  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 constituting the parallel shaft gear speed reducer 38, and the wheels Is transmitted to the bearing portion C. At this time, since the rotation of the motor rotating shaft 25 is decelerated by the reducer part B and transmitted to the wheel bearing part C, even when the motor part A employs a low torque, high speed rotation type electric motor 26, It is possible to transmit the necessary torque to the rear wheel 14 (see FIGS. 10 and 11).

  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 38 capable of obtaining a large reduction ratio, the in-wheel motor drive device 21 having a compact and high reduction ratio can be obtained. Further, since the parallel shaft gear reducer 38 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, as shown in FIGS. 10 and 11, 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.

21 In-wheel motor drive device 33 Output gear (fourth gear)
38 parallel shaft gear reducer 43 wheel bearings 44, 45 outer raceway 46 outer ring 47, 49 inner raceway 48 hub wheel 50 inner ring 51 rolling element 55 shaft (inboard side shaft)
A Motor part B Reducer part C Wheel bearing part

Claims (4)

An in-wheel motor drive device comprising a motor unit, a speed reducer unit configured with a parallel shaft gear reducer, and a wheel bearing unit configured with a wheel bearing,
The parallel shaft gear reducer has an output gear that transmits a driving force to the wheel bearing, and the wheel bearing includes an outer ring having a double-row outer raceway formed on an inner peripheral surface, and an outer peripheral surface. A hub wheel and an inner ring formed with an inner raceway surface facing the outer raceway surface, and a double row rolling element interposed between the outer raceway surface of the outer ring and the inner raceway surface of the hub ring and the inner ring. Prepared,
The in-wheel motor drive apparatus according to claim 1, wherein the inner ring of the wheel bearing has a structure in which a shaft portion that supports an output gear of the parallel shaft gear reducer is integrally formed.   The in-wheel motor drive device according to claim 1, wherein the shaft portion of the inner ring and the output gear of the parallel shaft gear reducer are integrally formed.   3. The in-wheel motor drive device according to claim 1, wherein the inner ring is configured to be fitted with a hub ring so as to be able to transmit torque. 4.   The in-wheel motor drive device according to any one of claims 1 to 3, wherein the inner ring and the hub ring are fixed by caulking or nut tightening.

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