JP2017024613A - In-wheel motor driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain meshing of gears constituting a parallel shaft reduction gear in a good condition even if bending moment caused by lateral force is applied to the gears.SOLUTION: An in-wheel motor driving device 21 is provided which comprises: a motor part A; a reduction gear part B constituted of a parallel shaft reduction gear 39 comprised of a plurality of gears 30-33; a bearing part C for a wheel; and a casing 22 storing the motor part A and the reduction gear part B, and in which the first-fourth gears 30-33 of the parallel shaft reduction gear 39 are rotatably supported by rolling bearings 40 and 42-46 relative to the casing 22. The parallel shaft reduction gear 39 comprises the fourth gear 33 that transmits driving power to the bearing part C for a wheel and the third gear 32 that meshes with the fourth gear 33. The fourth gear 33 and the rolling bearings 45 and 46 therefor and the third gear 32 and the rolling bearings 43 and 44 therefor are integrated using joining members 59 and 60, and the joining members 59 and 60 are attached to the casing 22.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.

  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. The output gear of the parallel shaft gear reducer meshes with the second counter gear and transmits the driving force to the axle of the wheel hub.

  In an in-wheel motor drive device equipped with such a parallel shaft gear reducer, when turning during vehicle travel, not only the longitudinal direction of the wheel but also the bending moment due to the lateral force is applied to the axle of the wheel hub and the parallel connected to the axle. It will be added to the output gear of the shaft gear reducer. When a bending moment due to such a lateral force is applied, a twisting force acts on the output gear of the parallel shaft gear reducer, and the output gear tilts with respect to the second counter gear.

  As described above, when the output gear is inclined with respect to the second counter gear, the meshing between the second counter gear and the output gear is deteriorated, and the tooth surface is partially contacted between the second counter gear and the output gear. Abnormal noise and wear occur. Such abnormal noise and wear due to the contact of the tooth surface causes noise and vibration, and becomes a noise and vibration phenomenon uncomfortable for the passenger in the passenger compartment.

  As a measure to solve such problems, a magnetic coupling is provided between the output gear of the parallel shaft gear reducer and the axle of the wheel hub, and this magnetic coupling blocks the shaft inclination of the output gear due to the wheel hub twisting. There is also a means to do. However, the installation of such a magnetic coupling increases the cost of the apparatus, and the assemblability may be reduced. In addition, the use of magnetic force may cause contamination due to the suction of foreign matter and reduce the life of the apparatus.

  Therefore, the present invention has been proposed in view of the above-described problems, and the object of the present invention is to achieve good meshing of the gears constituting the parallel shaft gear reducer even when a bending moment due to lateral force is applied. An object of the present invention is to provide an in-wheel motor drive device that can be maintained.

  As technical means for achieving the above-mentioned object, the present invention provides a motor unit, a speed reducer unit composed of a parallel shaft gear reducer composed of a plurality of gears, a wheel bearing unit, a motor unit and a speed reducer. And an in-wheel motor drive device in which each gear of the parallel shaft gear reducer is rotatably supported by a bearing with respect to the casing. The parallel shaft gear reducer includes a wheel bearing portion. An output gear that transmits a driving force to the motor, and an intermediate gear that meshes with the output gear. The output gear and its bearing are integrated with the intermediate gear and the bearing by a coupling member, and the coupling member is attached to the casing. Features.

  In the in-wheel motor drive device of the present invention, the output gear and the bearing thereof, and the intermediate gear and the bearing meshing with the output gear are integrated by the coupling member, so that the inter-shaft distance and the shaft of the output gear and the intermediate gear are integrated. The inclination can always be kept constant. Therefore, even if a bending moment due to lateral force is applied from the wheel bearings to the output gear of the parallel shaft gear reducer during turning, the output gear and the intermediate gear By keeping the inter-shaft distance and the shaft inclination constant at all times, the meshing between the output gear and the intermediate gear can be maintained in a good state.

  The coupling member in the present invention includes a large-diameter cylindrical portion that accommodates a bearing attached to the shaft portion of the output gear, a small-diameter tubular portion that accommodates a bearing attached to the shaft portion of the intermediate gear, and a large-diameter cylindrical shape. It is desirable to be comprised by the connection part which connects a part and a small diameter cylindrical part integrally. In this way, an integrated structure of the output gear and the intermediate gear can be easily realized.

  In the connecting portion in the present invention, a plate-like portion connecting the large-diameter cylindrical portion and the small-diameter cylindrical portion, and a rib portion connecting the outer peripheral surface of the large-diameter cylindrical portion and the outer peripheral surface of the small-diameter cylindrical portion are integrated. It is desirable to make the structure formed in this. In this way, the rigidity of the coupling member can be improved, and a highly rigid integrated structure of the output gear and the intermediate gear can be easily realized.

  In the present invention, a structure in which a shim for applying a preload to the bearing is interposed between the coupling member and the outer ring of the bearing is desirable. In this way, since the preload can be applied to the deep groove ball bearing and the angular ball bearing that support the output gear and the intermediate gear, the bearing support rigidity can be increased, and the generation of noise and vibration can be suppressed. .

  According to the present invention, since the distance between the output gear and the intermediate gear and the shaft inclination of the intermediate gear can always be kept constant, the bending moment due to the lateral force is caused from the wheel bearing portion to the output gear of the parallel shaft gear during turning. In addition, even if a twisting force based on a bending moment due to a lateral force is applied, the distance between the output gear and the intermediate gear and the shaft inclination are always kept constant, so that the output gear and the intermediate gear have good meshing. It can be maintained in a state.

  As a result, it is possible to prevent abnormal noise and wear due to the contact of the tooth surface, improve the assembly of the parallel shaft gear reducer, and easily realize a reliable and long-life in-wheel motor drive device. be able to.

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 assembly exploded perspective view which shows the integral structure by the coupling member of FIG. FIG. 2 is an assembled perspective view showing an integrated structure of the coupling member of FIG. 1. It is a partial expanded sectional view which shows the X section of FIG. It is a perspective view which shows the modification of a pair of coupling member. It is a top view which shows schematic structure of the electric vehicle carrying an in-wheel motor drive device. FIG. 8 is a rear sectional view showing the electric vehicle of FIG. 7.

  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. 7 is a schematic plan view of the electric vehicle 11 on which the in-wheel motor drive device 21 is mounted, and FIG. 8 is a schematic cross-sectional view of the electric vehicle 11 as viewed from the rear.

  As shown in FIG. 7, 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. Equip. As shown in FIG. 8, 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. 7 and 8) as a drive wheel. The motor part A and the speed reducer part B are accommodated in the casing 22 and attached to the wheel housing 15 (see FIG. 8) 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 described above. 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 means of rolling bearings 43, 44 via coupling members 59, 60 described later. Has been. 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 via the coupling members 59, 60 by rolling bearings 45, 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. 7 and 8). 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. 8) 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 of the wheel bearing 48 in the axial direction to prevent intrusion of muddy water or lubricating oil and leakage of grease sealed in the bearing.

  The wheel bearing 48 is fastened and fixed to the parallel shaft gear reducer 39 by screwing a nut 56 into a male screw portion 55 formed at the end of the outboard side shaft portion 47 of the reducer output shaft 37. Yes. 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 57 of the reduction gear output shaft 37. The rear wheel 14 (see FIGS. 7 and 8) is connected to the hub wheel 49 of the wheel bearing 48 by a hub bolt 58.

  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.

  As shown in FIG. 1, the in-wheel motor drive device 21 includes a third gear 32 that is a second-stage reduction unit in the parallel shaft gear reducer 39, rolling bearings 43 and 44 thereof, a fourth gear 33, and The rolling bearings 45 and 46 are integrated by the coupling members 59 and 60, and the coupling members 59 and 60 are attached to the casing 22.

  FIG. 3 is an exploded perspective view of the gear unit 61 in which the third gear 32 and the rolling bearings 43 and 44, the fourth gear 33 and the rolling bearings 45 and 46 are integrated by the coupling members 59 and 60, and FIG. FIG. 6 is a perspective view of the completed assembly of the gear unit 61 of FIG.

  As shown in FIGS. 3 and 4, in the gear unit 61, the third gear 32 and the rolling bearings 43 and 44, the coupling members 59 and 60 for integrating the fourth gear 33 and the rolling bearings 45 and 46 are the same. It consists of a pair of metal members having the same material and shape.

  The coupling members 59 and 60 are manufactured, for example, by pressing. High rigidity such as carbon steel (S45C, S55C, etc.), general structural steel (SS400, etc.), stainless steel (SUS430, SUS304, etc.), pressed steel plate (SPCC material), STKM steel, etc. The material is effective.

  The rolling bearings 43 and 44 of the third gear 32 and the rolling bearings 45 and 46 of the fourth gear 33 are formed with inner rings 62 and 63 having inner raceways formed on the outer circumferential surface and outer raceways formed on the inner circumferential surface. The outer races 64, 65, a plurality of rolling elements 66, 67 interposed between the inner raceway surface of the inner races 62, 63 and the outer raceway surface of the outer rings 64, 65, and the rolling members 66, 67 in the circumferential direction. It is a ball bearing such as a deep groove ball bearing constituted by a cage (not shown) held at equal intervals.

  Each of the coupling members 59 and 60 includes a large-diameter cylindrical portion 68 that accommodates the rolling bearings 45 and 46 attached to the shaft portion 36 of the fourth gear 33 and a rolling bearing attached to the shaft portion 35 of the third gear 32. The small-diameter cylindrical portion 69 that accommodates 43 and 44, and the plate-shaped portion 70 that is a connecting portion that integrally connects the large-diameter cylindrical portion 68 and the small-diameter cylindrical portion 69. By having such a structure, an integrated structure of the fourth gear 33 and the third gear 32 can be easily realized.

  The large-diameter cylindrical portion 68 of the coupling members 59 and 60 has a flange portion 71 that integrally extends radially inward from the outer end portion thereof, and the inside of the flange portion 71 is open. The outer ring 65 of the rolling bearings 45 and 46 press-fitted into the large-diameter cylindrical portion 68 is prevented from coming off by coming into contact with the flange portion 71. Similarly, the small-diameter cylindrical portion 69 of the coupling members 59 and 60 has a flange portion 72 that integrally extends radially inward from the outer end portion thereof, and the inside of the flange portion 72 is open. The outer ring 64 of the rolling bearings 43 and 44 press-fitted into the small-diameter cylindrical portion 69 is prevented from coming off by coming into contact with the flange portion 72.

  By using the coupling members 59 and 60 having the above-described configuration, the fourth gear 33 and the rolling bearings 45 and 46, the third gear 32 and the rolling bearings 43 and 44 are assembled as follows, and the gear unit 61 is assembled. Is configured.

  That is, the inner ring 63 of the rolling bearings 45 and 46 is press-fitted into the shaft portion 36 on the inboard side and the outboard side of the fourth gear 33, and the intermediate shaft 35 of the third gear 32 is rolled on the inboard side and the outboard side. The inner rings 62 of the bearings 43 and 44 are press-fitted.

  Then, the outer ring 65 of the rolling bearings 45 and 46 assembled to the fourth gear 33 is press-fitted into the large-diameter cylindrical portion 68 of the coupling members 59 and 60, and the rolling bearings 43 and 44 assembled to the third gear 32 are inserted. The outer ring 64 is press-fitted into the small diameter cylindrical portion 69 of the coupling members 59 and 60.

  When the outer rings 64 and 65 of the rolling bearings 43 to 46 are press-fitted into the large-diameter cylindrical portion 68 and the small-diameter cylindrical portion 69 of the coupling members 59 and 60, the outer ring 65 and the large-diameter cylindrical portion 68 of the rolling bearings 45 and 46 are inserted. A ring-shaped shim 73 is interposed between the outer ring 64 and the small-diameter cylindrical portion 69 of the rolling bearings 43 and 44 (see FIG. 5).

  By assembling such shims 73 and 74, a preload can be applied to the rolling bearings 43 to 46. Thereby, since the preload can be applied to the deep groove ball bearings and the angular ball bearings constituting the rolling bearings 43 to 46, the support rigidity of the rolling bearings 43 to 46 can be increased, and the generation of abnormal noise and vibration is suppressed. can do.

  The gear unit 61 in which the third gear 32 and the rolling bearings 43 and 44 are integrated with the fourth gear 33 and the rolling bearings 45 and 46 by the pair of coupling members 59 and 60 as described above is as shown in FIG. In addition, one coupling member 59 is fitted and fixed in the opening hole 76 formed in the partition wall surface 75 of the casing 22, and the other coupling member 60 is inserted into the opening hole 78 formed in the partition wall surface 77 of the casing 22. Fit and fix. In this way, the gear unit 61 is incorporated in the speed reducer part B of the in-wheel motor drive device 21.

  In the in-wheel motor drive device 21, the fourth gear 33 and the rolling bearings 45 and 46, and the third gear 32 and the rolling bearings 43 and 44 that mesh with the fourth gear 33 are integrated by the coupling members 59 and 60. By providing the highly rigid gear unit 61, the inter-axis distance and the shaft inclination of the fourth gear 33 and the third gear 32 can always be kept constant.

  Therefore, even when a bending moment due to a lateral force is applied from the wheel bearing portion C to the fourth gear 33 of the parallel shaft gear reducer 39 when turning, for example, even if a twisting force based on the bending moment due to the lateral force acts, the gear The coupling between the fourth gear 33 and the third gear 32 is maintained in a good state by always maintaining the inter-axis distance and the shaft inclination of the fourth gear 33 and the third gear 32 by the coupling members 59 and 60 of the unit 61. Can be maintained.

  As a result, in the gear unit 61, abnormal noise and wear due to contact between the tooth surfaces of the fourth gear 33 and the tooth surfaces of the third gear 32 can be prevented and boarding in the passenger compartment while suppressing noise and vibration. A comfortable environment for the person. Further, since it is not necessary to position the distance between the shafts of the fourth gear 33 and the third gear 32 on the casing side, the assembly of the fourth gear 33 and the third gear 32 is easy and the assembly cost can be reduced.

  In the above embodiment, the connecting members 59 and 60 in which the connecting portion that connects the large-diameter cylindrical portion 68 and the small-diameter cylindrical portion 69 is the plate-like portion 70 have been described, but the present invention is not limited to this. Further, the connecting members 79 and 80 having the connecting portion shown in FIG. 6 may be used.

  The connecting parts of the coupling members 79 and 80 shown in the figure include a plate-like part 81 that connects the large-diameter cylindrical part 68 and the small-diameter cylindrical part 69, the outer peripheral surface of the large-diameter cylindrical part 68, and the small-diameter cylindrical part 69. The rib part 82 which connects with the outer peripheral surface of this is comprised integrally.

  As described above, the connecting portion between the large-diameter cylindrical portion 68 and the small-diameter cylindrical portion 69 is configured by the plate-like portion 81 and the rib portion 82, whereby the rigidity of the coupling members 79 and 80 can be further improved. In addition, a highly rigid integrated structure of the fourth gear 33 and the third gear 32 can be easily realized.

  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 a necessary torque to the rear wheel 14 (see FIGS. 7 and 8).

  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, as shown in FIGS. 7 and 8, the electric vehicle 11 having the rear wheel 14 as a driving wheel is illustrated, but the front wheel 13 may be a driving wheel or a four-wheel driving 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 22 Casing 32 Intermediate gear (third gear)
33 Output gear (4th gear)
35 Shaft of intermediate gear 36 Shaft of output gear 39 Parallel shaft gear reducer 43 to 46 Bearing (rolling bearing)
59,60 Coupling member 64,65 Outer ring 68 Large-diameter cylindrical portion 69 Small-diameter cylindrical portion 70 Connecting portion (plate-like portion)
73, 74 Shim 79, 80 Coupling member 81 Plate part 82 Rib part A Motor part B Reducer part C Wheel bearing part

Claims (4)

The parallel shaft gear reducer comprising: a motor unit; a reducer unit configured by a parallel shaft gear reducer including a plurality of gears; a wheel bearing unit; and a casing that houses the motor unit and the reducer unit. An in-wheel motor drive device in which each gear is rotatably supported by a bearing with respect to a casing,
The parallel shaft gear reducer includes an output gear that transmits a driving force to the wheel bearing portion, and an intermediate gear that meshes with the output gear, and the output gear and its bearing, and the intermediate gear and its bearing. An in-wheel motor drive device characterized by being integrated by a coupling member and attaching the coupling member to the casing.   The coupling member includes a large-diameter cylindrical portion that accommodates a bearing attached to the shaft portion of the output gear, a small-diameter tubular portion that accommodates a bearing attached to the shaft portion of the intermediate gear, and the large-diameter tube. The in-wheel motor drive device of Claim 1 comprised by the connection part which connects a shape part and the said small diameter cylindrical part integrally.   The connecting portion is integrally formed of a plate-like portion connecting the large-diameter cylindrical portion and the small-diameter cylindrical portion, and a rib portion connecting the outer peripheral surface of the large-diameter cylindrical portion and the outer peripheral surface of the small-diameter cylindrical portion. The in-wheel motor drive device of Claim 2 which makes the structure formed in.   The in-wheel motor drive device according to any one of claims 1 to 3, wherein a shim for applying a preload to the bearing is interposed between the coupling member and an outer ring of the bearing.

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