JP2017003026A - 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: An 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. The second-fourth gears 31-33 constituting the parallel axis gear reducer 39 and the bearings 42, 44, 45 are unified by a carrier 59, and the carrier 59 is attached to the casing 22.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, the work of individually assembling a plurality of gears is very complicated, and there are problems that the total sum of tolerances increases due to the large number of parts, and the design of the apparatus becomes complicated.

  Therefore, the present invention has been proposed in view of the above-described problems, and the object of the present invention is to reduce the number of parts and to easily and easily assemble gears and bearings constituting a parallel shaft gear reducer. The object is to provide a vehicle 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. A motor drive unit for a vehicle in which each gear of the parallel shaft gear reducer is rotatably supported by a bearing with respect to the casing, and the gears and the bearing constituting the parallel shaft gear reducer are unitized by a carrier, The carrier is attached to the casing.

  In the vehicle motor drive device of the present invention, since the gears and bearings constituting the parallel shaft gear reducer are unitized by the carrier and the carrier is attached to the casing, the plurality of gears and bearings can be assembled as one unit. As a result, the assembly work can be simplified. In addition, since the number of parts can be reduced, the total sum of tolerances can be reduced, and the design of the apparatus is simplified. Furthermore, since it is not necessary to measure and select shims until the bearing is assembled, the cost of the apparatus can be reduced.

  The bearing according to the present invention 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 cylindrical portion of the carrier, the inner raceway surface of the gear shaft portion, and the carrier. It is desirable that the main part is composed of a rolling element interposed between the outer raceway surface of the cylindrical part. In this way, an integral structure of the gear and the bearing can be easily realized.

  The bearing according to the present invention preferably has a double row angular ball bearing structure in which preload is applied by caulking the shaft end of the gear or by nut tightening at the shaft end of the gear. 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.

  It is desirable that the bearing in the present invention is housed and assembled in an annular recess formed on the side of the gear. Thus, by housing the bearing in the annular recess of the 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 the gears and bearings constituting the parallel shaft gear reducer are unitized by the carrier and the carrier is attached to the casing, a plurality of gears and bearings can be assembled as one unit. Work can be simplified. In addition, since the number of parts can be reduced, the total sum of tolerances can be reduced, and the design of the apparatus is simplified. Furthermore, since it is not necessary to measure and select shims until the bearing is assembled, the cost of the apparatus can be reduced. 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 a side view which shows the unit of the parallel shaft gear reducer of FIG. It is an expanded sectional view which follows the PP line of FIG. FIG. 2 is an assembled perspective view showing a unit of the parallel shaft gear reducer of FIG. 1. FIG. 6 is an exploded perspective view showing a unit of the parallel shaft gear reducer of FIG. 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. 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. 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. 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 41 of the second gear 31 is supported by a rolling bearing 42 so as to be rotatable with respect to a carrier 59 described later. 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 carrier 59 by a rolling bearing 44. The fourth gear 33 to which the reduction gear output shaft 37 is attached and fixed is supported by the rolling bearing 45 so as to be rotatable with respect to the carrier 59. 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 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 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.

  In the in-wheel motor drive device 21, as shown in FIG. 1, the first gear 30 among the first to fourth gears 30 to 33 configuring the parallel shaft gear reducer 39 is connected to the motor rotation shaft 25. Because of the high speed rotation, it is difficult to unitize the first gear 30 and the rolling bearing 40. Therefore, in this embodiment, the second to fourth gears excluding the first gear 30 among the first to fourth gears 30 to 33 and the rolling bearings 40, 42, 44, 45 constituting the parallel shaft gear reducer 39. 31 to 33 and rolling bearings 42, 44, 45 are unitized by a carrier 59, and the carrier 59 is attached to the casing 22.

  3 is a side view of a reduction gear unit 60 in which the second to fourth gears 31 to 33 and the rolling bearings 42, 44, and 45 are unitized by a carrier 59, and FIG. 4 is a cross-sectional view taken along the line P-P in FIG. 5 is an assembled perspective view of the speed reducer unit 60. FIG. 6 is an exploded perspective view of the speed reducer unit 60. FIG.

  As shown in FIGS. 3 to 6, in the speed reducer unit 60, the carrier 59 for unitizing the second to fourth gears 31 to 33 and the rolling bearings 42, 44, and 45 is a first located on the input side. The carrier member 61 and the second carrier member 62 located on the output side are divided into two parts. Carbon steel (S45C, S55C, etc.), general structural steel (SS400, etc.), stainless steel (SUS430, SUS304, etc.), pressed steel plate (SPCC material), STKM steel, etc. are effective as the carrier material.

  The first carrier member 61 is a substantially elliptical stepped cylindrical member constituted by an upper cylindrical portion 63 and a lower cylindrical portion 64. The upper cylindrical portion 63 is accommodated in the annular recess 75 of the fourth gear 33, and an outer ring 87 of the rolling bearing 45 that supports the fourth gear 33 is integrally formed on the inner periphery. The lower cylindrical portion 64 is accommodated in the annular recess 74 of the second gear 31, and an outer ring 77 of the rolling bearing 42 that supports the second gear 31 is integrally formed on the inner periphery. Since the first gear 30 is disposed on the side of the upper tubular portion 63 and above the lower tubular portion 64 (see FIG. 1), the first gear 30 and the first gear 30 are disposed on the upper portion of the lower tubular portion 64. An opening 65 is provided so that the two gears 31 can be engaged with each other (see FIGS. 5 and 6).

  The second carrier member 62 is a substantially elliptical plate-like member composed of an opening 66 formed in the upper portion and a recessed portion 67 formed in the lower portion. The outboard side end of the shaft portion 36 of the fourth gear 33 is inserted into the opening 66 of the second carrier member 62. A rolling bearing 44 that rotatably supports the end portion on the outboard side of the intermediate shaft 35 is fitted in the recessed portion 67 of the second carrier member 62.

  The 1st carrier member 61 and the 2nd carrier member 62 which consist of the above structure comprise the following connection structures.

  That is, two rods 68 project from the second carrier member 62, and two holes 69 are provided in the first carrier member 61 correspondingly (see FIG. 6). The rod 68 of the second carrier member 62 is inserted into the hole 69 of the first carrier member 61 and fixed by an appropriate means such as welding, so that the first carrier member 61 and the second carrier member 62 are integrated (FIG. 5). The rod 68 of the second carrier member 62 has a substantially triangular cross-sectional shape in order to avoid interference with the second gear 31 and the fourth gear 33.

  As described above, the speed reducer unit 60 in which the second to fourth gears 31 to 33 and the rolling bearings 42, 44, and 45 are unitized by the carrier 59 that connects the first carrier member 61 and the second carrier member 62. As shown in FIG. 1, the first carrier member 61 is fixed to the wall surface 70 positioned on the speed reducer input side of the casing 22, and the second carrier member 62 is positioned on the speed reducer output side of the casing 22. Is fixed to the in-wheel motor drive device 21 so as to be incorporated into the speed reducer part B.

  In this in-wheel motor drive device 21, the second to fourth gears 31 to 33 and the rolling bearings 42, 44, 45 constituting the parallel shaft gear reducer 39 are unitized by a carrier 59, and the carrier 59 is attached to the casing 22. As a result, the second to fourth gears 31 to 33 and the rolling bearings 42, 44, and 45 can be assembled as one unit, so that the assembling work can be simplified. In addition, since the number of parts can be reduced, the total sum of tolerances can be reduced, and the design of the apparatus is simplified. Furthermore, since it is not necessary to measure and select shims until the rolling bearing is assembled, the cost of the apparatus can be reduced.

  As shown in FIGS. 1 and 4, in the reduction gear unit 60, the second gear 31 forms an integral structure with the rolling bearing 42, and the fourth gear 33 forms an integral structure with the rolling bearing 45.

  The second gear 31 includes a shaft portion 41 fitted to the intermediate shaft 35 and a tooth portion 72 that meshes with the first gear 30. An annular recess 74 is formed between the shaft portion 41 and the tooth portion 72 on the inboard side portion of the second gear 31, and the rolling bearing 42 is accommodated and assembled in the annular recess 74. The fourth gear 33 includes a shaft portion 36 fitted to the inboard side shaft portion 38 of the reduction gear output shaft 37 and a tooth portion 73 that meshes with the third gear 32. An annular recess 75 is formed between the shaft portion 36 and the tooth portion 73 on the inboard side of the fourth gear 33, and the rolling bearing 45 is accommodated and assembled in the annular recess 75.

  As described above, the rolling bearing 42 is accommodated in the annular recess 74 of the second gear 31 and the rolling bearing 45 is accommodated in the annular recess 75 of the fourth gear 33, so that the second gear 31, the rolling bearing 42, and the fourth gear are provided. In the assembly structure of the gear 33 and the rolling bearing 45, the axial width can be reduced, and the protruding of the rolling bearings 42 and 45 to the outside in the axial direction can be suppressed, and the in-wheel motor drive device 21 can be made compact. be able to.

  Here, since the fourth gear 33 is an output gear that becomes high torque after deceleration in the parallel shaft gear reducer 39, the fourth gear 33 is a gear having a larger axial width than the second gear 31 in order to ensure the strength of the teeth. It has become. Accordingly, the annular recess 75 of the fourth gear 33 can be formed deeper in the axial direction than the annular recess 74 of the second gear 31. As a result, in the second gear 31, approximately half of the rolling bearing 42 is accommodated in the annular recess 74, whereas in the fourth gear 33, substantially the entire rolling bearing 45 is accommodated in the annular recess 75. Can do.

  In this embodiment, the fourth gear 33 having a large axial width secures rigidity in a 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. Therefore, the fourth gear 33 is supported by the inboard side rolling bearing 45 alone, but a rolling bearing is also provided on the outboard side of the fourth gear 33 so that the fourth gear 33 is connected to the inboard side. It is also possible to adopt a double-supported structure that is supported by both the side rolling bearing 45 and the outboard side rolling bearing.

  In the reduction gear unit 60, the rolling bearing 42 that rotatably supports the second gear 31 includes a shaft portion 41 of the second gear 31, an inner ring 76, an outer ring 77, rolling elements 78 and 79, and a cage (not shown). It consists of As shown in FIG. 4, the shaft portion 41 of the second gear 31 has one inner raceway surface 80 formed on the outer peripheral surface thereof. The inner ring 76 is press-fitted into the small diameter step portion 81 of the shaft portion 41 of the second gear 31. A double-row raceway surface 80, 82 is constituted by one inner raceway surface 80 formed on the outer peripheral surface of the shaft portion 41 of the second gear 31 and the other inner raceway surface 82 formed on the outer peripheral surface of the inner ring 76. To do.

  The end portion of the small diameter step portion 81 of the shaft portion 41 into which the inner ring 76 is press-fitted is swaged outward by swing caulking, and the inner ring 76 is prevented from coming off with the swaged portion 83 and integrated with the shaft portion 41, A preload is applied to the rolling bearing 42. The outer ring 77 is formed integrally with the inner periphery of the lower cylindrical portion 64 of the first carrier member 61. On the inner peripheral surface of the outer ring 77, double-row outer raceway surfaces 84, 85 facing the inner raceway surfaces 80, 82 of the shaft portion 41 and the inner ring 76 are formed.

  The rolling bearing 42 including the shaft portion 41, the inner ring 76, and the outer ring 77 described above includes the inner raceway surfaces 80 and 82 formed on the outer peripheral surfaces of the shaft portion 41 and the inner ring 76, and the outer side formed on the inner peripheral surface of the outer ring 77. Double row angular contact ball bearing structure in which rolling elements 78 and 79 are interposed between the raceway surfaces 84 and 85, and the rolling elements 78 and 79 in each row are supported at equal intervals in the circumferential direction by a cage (not shown). Have In this way, the second gear 31 is integrated with the rolling bearing 42.

  The rolling bearing 45 that rotatably supports the fourth gear 33 includes the shaft portion 36 of the fourth gear 33, an inner ring 86, an outer ring 87, rolling elements 88 and 89, and a cage (not shown). . The shaft portion 36 of the fourth gear 33 has one inner raceway surface 90 formed on the outer peripheral surface thereof. The inner ring 86 is press-fitted into the small diameter step portion 91 of the shaft portion 36 of the fourth gear 33. The double inner raceway surfaces 90 and 92 are configured by one inner raceway surface 90 formed on the outer peripheral surface of the shaft portion 36 of the fourth gear 33 and the other inner raceway surface 92 formed on the outer peripheral surface of the inner ring 86. To do.

  The end of the small-diameter step portion 91 of the shaft portion 36 into which the inner ring 86 is press-fitted is swaged outward by swing caulking, and the inner ring 86 is prevented from coming off by the caulking portion 93 and integrated with the shaft portion 36, A preload is applied to the rolling bearing 45. The outer ring 87 is formed integrally with the inner periphery of the upper cylindrical portion 63 of the first carrier member 61. On the inner peripheral surface of the outer ring 87, double row outer raceway surfaces 94 and 95 are formed opposite to the inner raceway surfaces 90 and 92 of the shaft portion 36 and the inner ring 86.

  The rolling bearing 45 including the shaft portion 36, the inner ring 86, and the outer ring 87 described above includes the inner raceway surfaces 90 and 92 formed on the outer peripheral surfaces of the shaft portion 36 and the inner ring 86, and the outer side formed on the inner peripheral surface of the outer ring 87. A double row angular contact ball bearing structure in which rolling elements 88 and 89 are interposed between the raceways 94 and 95, and the rolling elements 88 and 89 in each row are supported at equal intervals in the circumferential direction by a cage (not shown). Have In this way, the fourth gear 33 forms an integral structure with the rolling bearing 45.

  Thus, by adopting the angular ball bearing structure in which preload is applied to the rolling bearing 42 of the second gear 31 and the rolling bearing 45 of the fourth gear 33, the support rigidity of the rolling bearings 42, 45 can be increased. And the generation of abnormal noise and vibration can be suppressed. In addition, although this embodiment demonstrated 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 embodiment, the rolling bearings 42 and 45 have a caulking structure in which the inner rings 76 and 86 are prevented from coming off by the caulking portions 83 and 93 and are integrated with the shaft portions 41 and 36. A male threaded portion is formed on the outer peripheral surfaces of the end portions of the shaft portions 41 and 36 of the shaft 31 and the fourth gear 33, a nut is screwed into the male threaded portion, and the inner rings 76 and 86 are prevented from coming off by tightening with the nut. It is good also as a nut fastening structure which integrates with the parts 41 and 36 and provides preload to the rolling bearings 42 and 45.

  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, 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. 8) has been described. The present invention is not limited to this, and the present invention can also be applied to a vehicle motor drive device 101 called an on-board type shown in FIG. In FIG. 9, the same parts as those in FIG.

  As shown in FIG. 9, the on-board type vehicle motor drive device 101 drives the rear wheel 14 via the left and right drive shafts 102. The vehicle motor drive device 101 includes a speed reducer B in which a speed reducer unit 60 having a parallel shaft gear speed reducer 39 is incorporated, and a motor part A that rotationally drives the speed reducer B. The vehicle motor drive device 101 includes two motor units A and two deceleration units B on the left and right sides.

  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 102 mainly includes a fixed type constant velocity universal joint 103 on the rear wheel 14 side, a sliding type constant velocity universal joint 104 on the speed reducer side, and an intermediate shaft 105 that connects between the two constant velocity universal joints 103 and 104. The configuration. The speed reducer output shaft 37 is connected to the sliding constant velocity universal joint 104 by spline fitting, and transmits the output of the speed reducing portion B to the rear wheel 14.

  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.

DESCRIPTION OF SYMBOLS 21 In-wheel motor drive device 22 Casing 31-33 Gear 36,41 Shaft part 39 Parallel shaft gear reducer 42,44,45 Bearing 59 Carrier 63,64 Cylindrical part 74,75 Annular recessed part 77,78,88,89 Moving body 80, 82, 90, 92 Inner raceway surface 84, 85, 94, 95 Outer raceway surface 83, 93 Clamping part 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,
A vehicle motor drive device characterized in that gears and bearings constituting the parallel shaft gear reducer are unitized by a carrier, and the carrier is attached to the casing.   The bearing 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 tubular portion of the carrier, the inner raceway surface of the shaft portion of the gear, and the The vehicle motor drive device according to claim 1, wherein a main part is constituted by a rolling element interposed between the outer raceway surface of the cylindrical part of the carrier.   The vehicle according to claim 1 or 2, wherein the bearing includes a double-row angular ball bearing structure in which preload is applied by caulking of a shaft end portion of a gear or nut tightening at a shaft end portion of the gear. Motor drive device.   4. The vehicle motor drive device according to claim 1, wherein the bearing is housed and assembled in an annular recess formed in a side portion of the gear.

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