JP2017065306A - In-wheel motor drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve inner structure of an in-wheel motor drive device compared with conventional ones.SOLUTION: An in-wheel motor drive device (10) comprises: a wheel have bearing part (11) having an outer ring (12) which is rotated integrally to a wheel, an inner stationery member (13) which is located on an inner periphery of the outer ring, and plural rolling elements (14) which are located in an annular clearance between the outer ring and the inner stationery member; a motor part (21) for driving the outer ring; and a deceleration part (31) which decelerates rotation of the motor part and transmits the same to the outer ring. The deceleration part is a parallel shaft type speed reducer, and includes an output gear (36), an input gear (32) which is coupled to a motor rotary shaft (22) of the motor part, and at least one intermediate gear (33, 35) which transmits rotation from the input gear to the output gear. At least one of these intermediate gears is so located as to be overlapped on an outer diameter side with respect to the outer ring and an axis (O) direction position of the outer ring.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an internal structure of an in-wheel motor drive device.

  Since the in-wheel motor is disposed inside the wheel, it is not necessary to be mounted on the vehicle body of an automobile like an engine (internal combustion engine), and is advantageous in that a large internal space of the vehicle body can be secured. As the in-wheel motor, those described in, for example, Japanese Patent Application Laid-Open No. 2008-44438 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2008-184111 (Patent Document 2) are known. The in-wheel motor structure described in Patent Document 1 and Patent Document 2 includes a wheel wheel, an outer ring side member that is coaxially coupled to the wheel wheel, and an inner ring side member that is disposed coaxially on the inner diameter side of the outer ring side member. And two rows of angular ball bearings disposed between the outer inner ring side members, a simple planetary gear mechanism disposed coaxially on the inner diameter side of the inner ring side member, and a simple planetary gear mechanism and the outer inner ring side member. And a counter gear mechanism disposed on the inner side in the axle direction, and a motor that is offset in a direction perpendicular to the axle and disposed in parallel with the axle.

JP 2008-44438 A JP 2008-184111 A

  In the conventional in-wheel motor, the outer ring side member, the inner ring side member, and the simple planetary gear mechanism are arranged coaxially with the axle. These end faces are covered with a cover-like power transmission member. The power transmission member connects the carrier of the simple planetary gear mechanism disposed on the inner diameter side with respect to the inner ring side member and the outer ring side member disposed on the outer diameter side with respect to the inner ring side member to each other to thereby connect the simple planetary gear. The output rotation of the mechanism is transmitted to the outer ring side member. However, such a connecting structure is complicated because rotation on the inner diameter side of the inner ring side member is taken out by bypassing the inner ring side member and transmitted to the outer diameter side from the inner ring side member. Therefore, it is disadvantageous in terms of assembly and cost.

  An object of the present invention is to provide an in-wheel motor structure that is improved compared to the prior art in view of the above-described circumstances.

  For this purpose, the in-wheel motor drive device according to the present invention includes an outer ring that rotates integrally with a wheel, an inner fixing member that is disposed on the inner periphery of the outer ring, and a plurality of rollers that are disposed in an annular gap between the outer ring and the inner fixing member. A wheel hub bearing section having a moving body, a motor section for driving the outer ring, and a deceleration section for decelerating the rotation of the motor section and transmitting it to the outer ring. Of these, the speed reducer is a parallel shaft type speed reducer, and the output gear provided coaxially on the outer peripheral surface of the outer ring, the input gear coupled to the motor rotating shaft of the motor unit, and the rotation transmitted from the input gear to the output gear. At least one of the intermediate gears, and at least one of the intermediate gears is disposed on the outer diameter side of the outer ring and overlaps with the axial position of the outer ring.

  According to the present invention, the inner fixing member of the wheel hub bearing portion is supported in a non-rotatable manner, the external gear teeth are provided on the outer ring outer periphery of the wheel hub bearing portion, and the outer ring is rotated by driving the output gear on the outer ring outer periphery. Therefore, the peripheral structure of the wheel hub bearing portion is not complicated. Therefore, it is advantageous in terms of assembly and cost. The parallel gear type reduction device refers to a reduction device in which the axis of the output gear, the axis of the intermediate gear, and the axis of the input gear extend in parallel to each other. The number of axes of the intermediate gear may be one or plural. Moreover, you may provide a planetary gear set in the one part axis | shaft of a parallel gear type reduction gear.

  In a simple configuration, the intermediate gear has only one external gear that meshes with the input gear and the output gear. Alternatively, the intermediate gear may include one external gear that meshes with the input gear and one external gear that meshes with the output gear, and these two intermediate gears may be coupled coaxially with the intermediate shaft. Alternatively, the intermediate gear includes one external gear meshed with the input gear, one external gear meshed with the output gear, and one intermediate gear to the other interposed between the two intermediate gears. One or more intermediate gears that transmit rotation to the intermediate gear may be included. As an embodiment of the present invention, all the intermediate gears are arranged on the outer diameter side of the outer ring. According to this embodiment, the axial direction position of the whole deceleration part can be arrange | positioned so that it may overlap with a wheel hub bearing part. Therefore, the axial dimension of the in-wheel motor drive device can be reduced. As another embodiment, a part of the intermediate gear may overlap with the outer ring in the axial direction.

  As a preferred embodiment of the present invention, the rolling elements are arranged in a double row, and the output gear is arranged from the axial position of the center of the rolling elements arranged in the row on the most axial direction to the row on the other side in the axial direction. It arrange | positions at the axial direction area | region between the axial direction position of the center of the rolling element arrange | positioned. According to this embodiment, the outer ring is stably supported by the double row rolling elements during the driving of the wheel. As another embodiment, a part or all of the output gear may be arranged so as to deviate from the axial region described above.

  As a further preferred embodiment of the present invention, the motor part is arranged offset from the axis of the wheel hub bearing part. According to this embodiment, a part or all of the motor unit can be arranged to overlap the axial position of the outer ring. Therefore, the axial dimension of the in-wheel motor drive device can be shortened. More preferably, the motor part is arranged on the outer diameter side of the outer ring of the wheel hub bearing part. More preferably, the motor unit is arranged so as to overlap with the position of the outer ring in the axial direction. In another embodiment, the motor unit is arranged to intersect the axis of the wheel hub bearing unit. Specifically, for example, the motor part and the wheel hub bearing part are arranged coaxially.

  As one embodiment of the present invention, the motor unit is disposed in a circle having a diameter equal to the inner diameter of the rim of the wheel wheel coupled to the outer ring. Alternatively, as one embodiment, the speed reduction portion is disposed in a circle having a diameter equal to the rim inner diameter of the wheel wheel coupled to the outer ring. According to this embodiment, an in-wheel motor drive device can be accommodated in the inner space area of a wheel. As another embodiment, a part of the motor part, the whole motor part, or a part of the speed reduction part may protrude from the circle to the outer diameter side.

  As a preferred embodiment of the present invention, the output gear and the outer ring are connected so as to be relatively displaceable in the radial direction, and the output gear has a large-diameter portion having a tooth tip and a tooth root on the outer periphery, and a small diameter formed at the center of the large-diameter portion. The cylinder part is rotatably supported by the casing of the speed reduction part via a bearing. According to this embodiment, the output gear can be stably supported regardless of the behavior of the outer ring. As a further preferred embodiment of the present invention, the cylindrical portion extends from the large diameter portion to both sides in the axial direction, and the bearings support both ends of the cylindrical portion.

  As one embodiment of the present invention, the output gear is connected to the outer ring by a spline having a positive radial clearance. According to this embodiment, the output gear and the outer ring are connected so as to be relatively displaceable in the radial direction, and torque transmission is enabled between the output gear and the outer ring.

  As a preferred embodiment of the present invention, the rolling elements of the wheel hub bearing portion are arranged in double rows, and the splines are arranged between the rows of rolling elements. According to this embodiment, the output gear can be stably supported regardless of the behavior of the outer ring.

  As a further preferred embodiment of the present invention, the spline allows sliding in the axial direction between the outer ring and the output gear. According to this embodiment, even when the outer ring is slightly displaced in the axial direction, displacement of the output gear in the axial direction can be avoided.

  Thus, according to this invention, the connection structure of a wheel hub bearing part and a deceleration part can be simplified. Therefore, it is advantageous in terms of assembly and cost.

It is a longitudinal cross-sectional view which shows the in-wheel motor drive device which becomes one Embodiment of this invention. It is a cross-sectional view which shows the same embodiment typically.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an in-wheel motor drive device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing the embodiment, and shows a state in which the inside of the speed reducing portion is cut along II-II in FIG. 1 and viewed in the axial direction. The in-wheel motor drive device 10 includes a wheel hub bearing portion 11 provided at the center of a wheel (not shown), a motor portion 21 that drives the wheel, and a speed reduction portion that decelerates the rotation of the motor portion and transmits it to the wheel hub bearing portion 11. 31 is provided. The motor unit 21 and the speed reduction unit 31 are arranged offset from the axis O of the wheel hub bearing unit 11.

  The wheel hub bearing 11 is disposed in an annular gap between the outer ring 12 as a wheel hub coupled to a wheel wheel (not shown), the inner fixing member 13 passed through the center hole of the outer ring 12, and the outer ring 12 and the inner fixing member 13. The plurality of rolling elements 14 are provided. The inner fixing member 13 includes a non-rotating fixing shaft 15, an inner race 16, and a retaining nut 17. The fixed shaft 15 extends in the axis O direction, is formed with a small diameter on one side in the axis O direction, and is formed with a large diameter on the other side in the axis O direction. The other end of the fixed shaft 15 in the axis O direction is directed to the inner side in the vehicle width direction and attached to the suspension member 101. One of the fixed shafts 15 in the direction of the axis O is directed outward in the vehicle width direction, and an annular inner race 16 is fitted to the outer periphery. Further, a retaining nut 17 is screwed to one end of the fixed shaft 15 in the axis O direction, and the inner race 16 is retained. In the following description, one side in the axis O direction means the outside in the vehicle width direction, and the other in the axis O direction means the inside in the vehicle width direction.

  The rolling elements 14 are arranged in double rows with a separation in the direction of the axis O. The outer diameter surface of the inner race 16 forms an inner raceway surface of the rolling elements 14 in the first row, and faces one inner diameter surface of the outer ring 12 in the axis O direction. On the other hand, the outer periphery of the central portion in the direction of the axis O of the fixed shaft 15 constitutes the inner raceway surface of the rolling elements 14 in the second row and faces the other inner diameter surface of the outer ring 12 in the direction of the axis O.

  A flange 12f is formed at one end of the outer ring 12 in the axis O direction. The flange 12f constitutes a coupling portion for coaxially coupling with the disc-shaped brake rotor 102 and a wheel (not shown). The outer ring 12 is coupled to the wheel by a flange 12f and rotates integrally with the wheel.

  As shown in FIG. 1, the motor unit 21 has a motor rotating shaft 22, a rotor 23, a stator 24, a motor casing 25, and a motor casing cover 25v, and sequentially from the axis M of the motor unit 21 to the outer diameter side in this order. Be placed. The motor unit 21 is a radial gap motor of an inner rotor and outer stator type, but may be of other types. For example, although not shown, the motor unit 21 may be an axial gap.

  An axis M serving as the rotation center of the motor rotation shaft 22 and the rotor 23 extends in parallel with the axis O of the wheel hub bearing portion 11. That is, the motor unit 21 is disposed offset from the axis O of the wheel hub bearing unit 11. Moreover, the axial direction position of the motor part 21 overlaps with the inner side fixing member 13 of the wheel hub bearing part 11 as shown in FIG. Thereby, the axial direction dimension of the in-wheel motor drive device 10 can be shortened. Both ends of the motor rotating shaft 22 are rotatably supported by the motor casing 25 via rolling bearings 27 and 28. The motor casing 25 has a substantially cylindrical shape, is coupled to the main body casing 38 at one end in the axis M direction, and is sealed by a circular motor casing cover 25v at the other end in the axis M direction. The motor unit 21 drives the outer ring 12.

  The speed reduction unit 31 includes an output gear 36 provided coaxially on the outer peripheral surface of the outer ring 12, an input gear 32 coupled to the motor rotation shaft 22 of the motor unit 21, and a plurality of transmissions that transmit rotation from the input gear to the output gear. Intermediate gears 33 and 35 and a main body casing 38 for housing these gears are provided.

  The input gear 32 is an external gear having a smaller diameter than the motor portion 21 and further has a smaller diameter cylindrical portion 32c at the center. The inner periphery of the cylindrical portion 32c is fitted to the outer periphery of the shaft portion 32s further extending in the axial direction from the motor rotating shaft 22 so as not to be relatively rotatable. Both ends of the cylindrical portion 32c are rotatably supported by the main body casing 38 via rolling bearings 32m and 32n. The rolling bearings 32m and 32n are fixed to the outer periphery of the cylindrical portion 32c.

  The main body casing 38 surrounds the axes O, M, and R extending in parallel to each other, covers the speed reduction portion 31 and the wheel hub bearing portion 11, and covers both sides of the speed reduction portion 31 in the axial direction. The cylindrical portion 32 c and the shaft portion 32 s constitute an input shaft of the speed reducing portion 31. One end surface in the axial direction of the main body casing 38 faces the brake rotor 102. The motor casing 25 is attached to the main body casing 38 and protrudes from the main body casing 38 to the other side in the axial direction. The main casing 38 accommodates all the rotating elements (shafts and gears) of the speed reducing unit 31.

  The motor casing 25 or the main body casing 38 may be connected and fixed to the suspension member 101 or the inner fixing member 13 via a connecting member (not shown). Thereby, the motor casing 25 and the main body casing 38 are supported by the suspension member 101.

  The small-diameter input gear 32 meshes with a first intermediate gear 33 that becomes a large-diameter external gear. The intermediate gear 33 is coupled coaxially with a second intermediate gear 35 that becomes a small-diameter external gear by an intermediate shaft 34. Both end portions of the intermediate shaft 34 are rotatably supported by the main body casing 38 via rolling bearings 34m and 34n. The first intermediate gear 33 and the second intermediate gear 35 are disposed between the rolling bearing 34m and the rolling bearing 34n, and are adjacent to each other. In the present embodiment, the first intermediate gear 33 and the intermediate shaft 34 are integrally formed, and the second intermediate gear 35 is fitted on the outer periphery of the intermediate shaft 34 so as not to be relatively rotatable. An axis R passing through the center of the intermediate shaft 34 extends in parallel with the axis O of the wheel hub bearing portion 11. Thereby, the deceleration part 31 is arranged offset from the wheel hub bearing part 11. The small-diameter second intermediate gear 35 meshes with the large-diameter output gear 36. The positional relationship between the axes O, R, and M is as shown in FIG.

  The output gear 36 is an external gear, and the outer ring 12 is fitted into the center hole of the output gear 36 so as not to be relatively rotatable. Such fitting is spline fitting, whereby the output gear 36 and the outer ring 12 are connected so as not to be relatively rotatable in the circumferential direction, and torque is transmitted between them. Specifically, spline grooves 40 are respectively formed on the inner peripheral surface of the output gear 36 and the outer peripheral surface of the outer ring 12. The spline groove 40 allows a slight relative displacement in the radial direction between the output gear 36 and the outer ring 12. Further, the spline groove 40 of the outer ring 12 is slidable in the direction of the axis O with respect to the spline groove 40 of the output gear 36. That is, the spline groove 40 allows relative displacement in the direction of the axis O between the output gear 36 and the outer ring 12. Alternatively, the fitting between the output gear 36 and the outer ring 12 is serration fitting.

  The tooth tip and the tooth bottom of the output gear 36 have a larger diameter than the outer peripheral surface of the outer ring 12. When viewed in the direction of the axis O, the outer peripheral portion of the output gear 36 and the outer peripheral portion of the first intermediate gear 33 overlap. A cylindrical portion 36 c is formed at the center of the output gear 36. Both end portions of the cylindrical portion 36c protrude from both end surfaces of the output gear 36 and are rotatably supported by the main body casing 38 via rolling bearings 36m and 36n. The rolling bearings 36m and 36n are fixed to the outer periphery of the cylindrical portion 36c. The cylindrical portion 36 c fitted with the outer ring 12 constitutes the output shaft of the speed reducing portion 31.

  Openings through which the outer ring 12 passes are formed on both sides of the body casing 38 in the direction of the axis O. Sealing materials 37c and 37d for sealing an annular gap with the outer ring 12 are provided in each opening. For this reason, the outer ring | wheel 12 used as a rotary body is accommodated in the main body casing 38 except for the axial O direction end part. The main casing 38 is installed across three axes O, R, and M that are parallel to each other.

  As shown in FIG. 2, the first intermediate gear 33, the second intermediate gear 35, and the intermediate shaft 34 are disposed on the outer diameter side of the outer ring 12. As shown in FIG. 1, the first intermediate gear 33, the second intermediate gear 35, and the intermediate shaft 34 are arranged so as to overlap with the position of the outer ring 12 in the axis O direction. The same applies to the input gear 32 and the output gear 36. In the present embodiment, as shown in FIG. 2, the first intermediate gear 33 and the second intermediate gear 35 are all disposed on the outer diameter side of the outer ring 12. Alternatively, as a modification (not shown), the intermediate shaft 34 is elongated to separate the large-diameter first intermediate gear 33 from the small-diameter second intermediate gear 35, and the outer periphery of the first intermediate gear 33 is connected to the outer ring 12 in the direction of the axis O. You may arrange | position so that it may overlap.

  Returning to the description of this embodiment, as shown in FIG. 1, the output gear 36 is located closest to the axis O in the other direction from the axial position of the center of the rolling elements 14 arranged in the row on the one side in the axis O most. It arrange | positions at the axial direction area | region between the axial direction position of the center of the rolling elements 14 arrange | positioned at a row | line | column. As a result, the outer ring 12 is stably supported by the double-row rolling elements 14 and 14 while the wheels are being driven. The spline groove 40 is disposed between the row of rolling elements 14 on one side in the axis O direction and the row of rolling elements 14 on the other side in the axis O direction.

  As shown in FIG. 2, the motor unit 21 and the speed reduction unit 31 are arranged in a circle 103 c having a diameter equal to the rim inner diameter of the wheel wheel coupled to the outer ring 12. Specifically, the output gear 36 is disposed in the circle 103c. Thereby, the motor part 21 and the deceleration part 31 can be accommodated in a wheel wheel.

  The axis R and the axis M are preferably arranged above the axis O. Thereby, it becomes easy to ensure the clearance from the road surface to the motor unit 21 and the clearance from the road surface to the speed reduction unit 31.

  Although the embodiments of the present invention have been described with reference to the drawings, the present invention is not limited to the illustrated embodiments. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

  As a modification (not shown), the speed reduction unit 31 is not limited to a parallel shaft type speed reducer, and may be a combination of a parallel shaft type speed reducer and a planetary gear speed reducer.

  As a modification (not shown), one end in the axial direction of the wheel hub bearing portion 11, the speed reduction portion 31, and the motor portion 21 is accommodated in the inner space of the wheel, and the other end in the axial direction of the motor portion 21 is the inner space of the wheel. It may protrude from the area.

  The in-wheel motor drive device according to the present invention is advantageously used in electric vehicles and hybrid vehicles.

10 in-wheel motor drive, 11 wheel hub bearing,
12 outer ring, 12f flange, 13 inner fixing member,
14 rolling elements, 15 fixed shaft, 16 inner race,
17 Retaining nut, 21 Motor part, 22 Motor rotating shaft,
23 rotor, 24 stator, 25 motor casing,
31 reduction gear, 32 input gear, 33 first intermediate gear,
34 intermediate shaft, 35 second intermediate gear, 36 output gear,
37c, 37d sealing material, 38 body casing,
40 spline groove, 101 suspension member,
102 Brake rotor, 103c Circle equal to rim inner diameter,
O, R, M axes.

Claims (10)

An outer ring that rotates integrally with a wheel, an inner fixing member that is disposed on the inner periphery of the outer ring, a wheel hub bearing portion that has a plurality of rolling elements that are disposed in an annular gap between the outer ring and the inner fixing member, and the outer ring A motor unit that drives the motor, and a speed reduction unit that decelerates the rotation of the motor unit and transmits it to the outer ring,
The speed reduction part is a parallel shaft type speed reducer, and an output gear provided coaxially on the outer peripheral surface of the outer ring, an input gear coupled to a motor rotation shaft of the motor part, and rotation from the input gear to the output gear An in-wheel motor drive device, wherein at least one of the intermediate gears is disposed so as to overlap an outer diameter side of the outer ring and an axial position of the outer ring.   2. The in-wheel motor drive device according to claim 1, wherein all of the intermediate gears are disposed on an outer diameter side of the outer ring. The rolling elements are arranged in a double row,
The output gear is located between the axial position of the center of the rolling elements arranged in the row on the most axial direction and the axial position of the center of the rolling elements arranged in the row on the other axial side. The in-wheel motor drive device of Claim 1 or 2 arrange | positioned in the axial direction area | region of.   The in-wheel motor drive device according to any one of claims 1 to 3, wherein the motor unit is arranged so as to be offset from an axis of the wheel hub bearing unit.   The in-wheel motor according to any one of claims 1 to 4, wherein at least a part of the motor part and the speed reduction part are arranged in a circle having a diameter equal to a rim inner diameter of a wheel wheel coupled to the outer ring. Drive device. The output gear and the outer ring are coupled so as to be relatively displaceable in a radial direction,
The output gear includes a large-diameter portion having a tooth tip and a tooth bottom on the outer periphery, and a small-diameter cylindrical portion formed at the center of the large-diameter portion,
The in-wheel motor drive device according to claim 1, wherein the cylindrical portion is rotatably supported by a casing of the speed reduction portion via a bearing. The cylindrical portion extends from the large diameter portion to both sides in the axial direction,
The in-wheel motor drive device according to claim 6, wherein the bearing supports both ends of the cylindrical portion.   The in-wheel motor drive device according to claim 6 or 7, wherein the output gear is connected to the outer ring by a spline having a positive radial gap. The rolling elements are arranged in a double row,
The in-wheel motor drive device according to claim 8, wherein the spline is disposed between the rows of the rolling elements with respect to an axial direction of the wheel hub bearing portion.   The in-wheel motor drive device according to claim 8 or 9, wherein the spline allows sliding in an axial direction between the outer ring and the output gear.

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