JP2019018735A - In-wheel motor drive device for vehicle - Google Patents

Abstract

To provide an in-wheel motor drive device for a vehicle, in which an axial dimension of a drive wheel is short.SOLUTION: A cylindrical roller bearing 48 is provided between an output helical gear 40 and a first casing 25 so as to be accommodated in a teeth width B of the output helical gear 40. Load, in a radial direction, on the output helical gear 40 is received by the first casing 25 via the cylindrical roller bearing 48, and load, in a thrust direction, on the output helical gear 40 is received by the first casing 25 via a main bearing 60. This eliminates the need for the output helical gear 40 to be supported by a ball bearing or a conical roller bearing, which is able to receive load in both radial direction and thrust direction, thus simplifying the respective structures of the peripheries of the output shaft 42 and the output helical gear 40. In addition, the dimension of the in-wheel motor drive device 10 for the vehicle in the direction of a second rotation center line C2 can be shortened.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an in-wheel motor drive device for a vehicle.

  An in-wheel motor drive device for a vehicle including an electric motor and a parallel shaft type gear reducer is known. For example, Patent Document 1 includes an electric motor, an input helical gear fixed to an input shaft to which the rotational driving force of the electric motor is input, and an output helical gear that meshes with the input helical gear. In addition, a vehicle in-wheel motor drive device is described that includes a parallel shaft gear reducer that decelerates and transmits the rotation of the electric motor from an output shaft fixed to the helical gear to the drive wheel. .

JP 2017-066511

  In the parallel shaft type gear reducer of the vehicle in-wheel motor driving apparatus as described above, the reaction force in the radial direction and the thrust direction is generated in the output helical gear by meshing with the input helical gear. For this reason, the output helical gear needs to be supported by a bearing capable of receiving loads in both the radial direction and the thrust direction. For example, in Patent Document 1, an output helical gear is supported by two rows of ball bearings. However, in such a support structure of the helical gear, there is a problem that the in-wheel motor drive device for a vehicle increases in size in the thrust direction of the helical gear, that is, the axial direction of the drive wheel.

  The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide a vehicle in-wheel motor drive device in which the dimensions of the drive wheels in the axial direction are short.

  The gist of the present invention is that: (a) an electric motor provided on a non-rotating member; and (b) an input that is provided so as to be rotatable about a first rotation center line and to which rotation of the electric motor is input. A helical gear, rotatably provided around a second rotation center line parallel to the first rotation center line, the output helical gear meshing with the input helical gear, and the output helical gear fixed A parallel-shaft gear reducer that has an output shaft that decelerates the rotation of the electric motor and outputs the output from the output shaft, and (c) an inner ring connected to the output shaft, and is fixed to the non-rotating member. An outer ring, and a rolling element provided between the inner ring and the outer ring, and a main bearing that receives a radial load and a thrust load, and outputs from the output shaft to the drive wheel. A wheel hub for transmission, and the electric motor comprising (d). An in-wheel motor drive device for a vehicle that drives the drive wheel attached to the wheel hub by a motor, (e) the output helical gear between the output helical gear and the non-rotating member (F) a radial load of the output helical gear is received by the non-rotating member via the cylindrical roller bearing, and (g) A load in the thrust direction of the output helical gear is received by the non-rotating member via the main bearing.

  According to the present invention, (e) a cylindrical roller bearing is provided between the output helical gear and the non-rotating member so that the output helical gear is accommodated within a tooth width of the helical gear, and (f) the The load in the radial direction of the output helical gear is received by the non-rotating member through the cylindrical roller bearing, and (g) the load in the thrust direction of the output helical gear is transmitted through the main bearing. It is received by a non-rotating member. In this way, the output helical gear does not necessarily have to be supported by a ball bearing or a tapered roller bearing that can receive loads in both the radial direction and the thrust direction as in the prior art. The structure around the output shaft and the output helical gear is simplified. In addition, since the cylindrical roller bearing is accommodated within the tooth width of the output helical gear, the dimension of the vehicle in-wheel motor drive device in the axial direction of the drive wheel can be shortened, and the weight can be reduced. Is also possible.

It is sectional drawing which shows the structure of the in-wheel motor drive device for vehicles which is one Example of this invention. It is sectional drawing to which the principal part of FIG. 1 was expanded. It is sectional drawing which shows the structure of the vehicle in-wheel motor drive device for a comparison, Comprising: It is a figure corresponding to FIG. 1 of this invention.

  In one embodiment of the present invention, the inner ring is concentrically and integrally connected to the output shaft. In this way, both the load in the thrust direction on the drive wheel side and the load in the thrust direction on the opposite side of the drive wheel of the output helical gear are transmitted through the main bearing to the It can be received by a non-rotating member.

  In one embodiment of the present invention, the inner ring is fastened with a nut to the output shaft. In this way, both the load in the thrust direction on the drive wheel side and the load in the thrust direction on the opposite side of the drive wheel of the output helical gear are transmitted through the main bearing to the It can be received by a non-rotating member.

  Hereinafter, an embodiment of a vehicle in-wheel motor drive device of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a diagram showing the structure of an in-wheel motor drive device (vehicle in-wheel motor drive device) 10 for an EV vehicle (electric vehicle) according to an embodiment of the present invention. It is sectional drawing by the plane which passes the below-mentioned 2nd rotation center line C2) and the rotating shaft (after-mentioned 1st rotation center line C1) of the electric motor 18. FIG. The in-wheel motor drive device 10 is provided inside the drive wheels 14, and includes an electric motor 18 that generates a driving force of the vehicle, a parallel shaft gear reducer 20 that decelerates and outputs the rotation of the electric motor 18, and a parallel. A wheel hub 22 that transmits the rotation output from the shaft gear reducer 20 to the drive wheels 14 is provided.

  The electric motor 18 is accommodated in the casing 24. The casing 24 is fixed to a non-rotating member such as a hub or a hub knuckle connected to a vehicle body (not shown) via a suspension device or the like, for example, and the casing 24 itself is also a non-rotating member. The casing 24 includes a first casing 25 on the drive wheel 14 side (opposite the electric motor 18), a second casing 26 in the center, and a third casing 27 on the opposite side (electric motor side) of the drive wheel 14 (not shown). It is comprised integrally by being fastened by.

  The electric motor 18 includes a stator 28 and a rotor 30. The stator 28 is fixed to the second casing 26 by fastening bolts 29. The rotor 30 integrally has an input shaft 32 that passes through the center thereof. Both ends of the input shaft 32 are supported by the second casing 27 and the first casing 25 via ball bearings 34 and cylindrical roller bearings 36, so that the input shaft 32 and the rotor 32 are rotated around the first rotation center line C1. It is provided rotatably.

  The parallel shaft gear reducer 20 includes an input helical gear 38, an output helical gear 40 that meshes with the input helical gear 38, and an output shaft 42. The input helical gear 38 is provided concentrically and integrally with the input shaft 32 by processing the drive wheel 14 side of the input shaft 32 of the electric motor 18 by, for example, grinding or polishing. The output helical gear 40 is concentrically and integrally connected to the output shaft 42 by press-fitting (for example, including serration fitting) and a retaining ring 44, and is provided in the first casing 25. The cylindrical roller bearing 48 is rotatably supported around a second rotation center line C2 parallel to the first rotation center line C1. The second rotation center line C <b> 2 is also the center line of the drive wheel 14.

  The output helical gear 40 has a larger diameter than the input helical gear 38 and has a larger number of teeth, and the rotational driving force input from the input shaft 32 of the electric motor 18 is decelerated in rotation. It is transmitted to the output shaft 42. For this reason, the output torque of the electric motor 18 can be amplified and transmitted from the output shaft 42 to the drive wheels 14.

  FIG. 2 is an enlarged view showing a main part of FIG. As shown in FIG. 2, the output helical gear 40 has an annular groove 40 a that is open on the drive wheel 14 side, and the first casing 25 is an annular bearing that protrudes into a portion surrounded by the annular groove 40 a. It has the support part 25a. The cylindrical roller bearing 48 includes an annular groove 40 a formed in the output helical gear 40, a groove side wall surface on the outer peripheral side of the annular groove 40 a of the output helical gear 40, and an annular bearing support portion 25 a of the first casing 25. Is interposed so as to receive a load in the radial direction. As shown in FIG. 2, the cylindrical roller bearing 48 is provided so that the output is accommodated within the tooth width B of the helical gear 40 in the thrust direction (the axial direction of the drive wheel 14).

  The cylindrical roller bearing 48 includes an outer ring 48 a having a U-shaped cross section that is fitted to the groove side wall surface on the outer circumferential side of the annular groove 40, and I that is fitted to the outer circumferential surface of the annular bearing support portion 25 a of the first casing 25. An inner ring 48b having a letter-shaped cross section, and a plurality of cylindrical rolling elements 48c arranged in a row between the outer ring 48a and the inner ring 48b, the outer ring 48a and the inner ring 48b being in the thrust direction It is configured to be relatively movable.

  The wheel hub 22 includes an inner ring 50 connected to the output shaft 42 of the parallel shaft gear reducer 20, an outer ring 52 fixed to the first casing 25, and two rows of spherical balls provided between the inner ring 50 and the outer ring 52. A rolling element 54 and a hub flange 58 are provided. The inner ring 50, the outer ring 52, and the two rows of spherical rolling elements 54 constitute a main bearing 60. In other words, the wheel hub 22 includes a main bearing 60 and a hub flange 58.

  An oil seal 62 is attached between the inner ring 50 and the outer ring 52 of the wheel hub 22 in order to seal the inside of the casing 24 in an oil-tight manner. An O-ring 64 is attached between the outer ring 52 and the first casing 25.

  The output shaft 42 is provided with a large diameter portion 42a so as to protrude to the outer peripheral side. The inner ring 50 of the wheel hub 22 is press-fitted into the output shaft 42 (for example, serration fitting or the like) so that the end surface opposite to the drive wheel 14 in the second rotation center line C2 direction abuts against the large-diameter portion 42a of the output shaft 42. And is fastened by a nut 66 attached to the drive wheel side of the output shaft 42. That is, the output shaft 42 of the parallel shaft type gear reducer 20 is concentrically and integrally connected to the inner ring 50 of the main bearing 60.

  The inner ring 50 of the wheel hub 22 is integrated with a hub flange 58, and a brake disc 68 and a wheel 70 are fastened to the hub flange 58 by bolts (not shown). A tire 72 is attached to the wheel 70. The driving wheel 14 is configured by the wheel 70 and the tire 72. The rotational driving force output from the output shaft 42 of the parallel shaft gear reducer 20 is driven via the inner ring 50 of the wheel hub 22 connected to the output shaft 42 and the hub flange 58 integrated with the inner ring 50. It is transmitted to the wheel 14.

  Since the main bearing 60 of the wheel hub 22 is a ball bearing, it can receive loads in both the radial direction and the thrust direction. A reaction force (load) in the radial direction and the thrust direction is transmitted to the wheel hub 22 from the drive wheel 14 in contact with the ground. The load is transmitted through the main bearing 60 of the wheel hub 22 to the casing 24 which is a non-rotating member, particularly It is received by the first casing 25.

  In the parallel shaft type gear reducer 20, reaction forces (loads) in the radial direction and the thrust direction are generated in the output helical gear 40 by meshing with the input helical gear 38. The radial load of the output helical gear 40 is received by the casing 24 which is a non-rotating member via the cylindrical roller bearing 48.

  The load in the thrust direction of the output helical gear 40 toward the drive wheel 14 is transmitted to the output shaft 42 by concentrically and integrally connecting the output helical gear 40 to the output shaft 42. The load transmitted to the output shaft 42 is transmitted to the main bearing 60 when the large diameter portion 42 a provided on the opposite side of the output shaft 42 from the drive wheel 14 presses the inner ring 50 of the main bearing 60.

  The load in the thrust direction of the output helical gear 40 on the opposite side of the drive wheel 14 is transmitted to the output shaft 42 by the output helical gear 40 being concentrically and integrally connected to the output shaft 42. . The load transmitted to the output shaft 42 is transmitted to the main bearing 60 when the nut 66 attached to the end of the output shaft 42 on the drive wheel side presses the inner ring 50 of the main bearing 60.

  Since the main bearing 60 is a ball bearing, it can receive a load not only in the radial direction but also in the thrust direction. For this reason, both the load in the thrust direction of the output helical gear 40 on the drive wheel 14 side and the load in the thrust direction on the opposite side of the drive wheel 14 are both non-rotating members via the main bearing 60. It is received by a casing 24.

  FIG. 3 is a cross-sectional view showing the structure of the in-wheel motor drive device 110 of the comparative example. In the in-wheel motor drive device 110, the inner ring 150 is not fastened to the output shaft 142 with a nut. In such a structure, the output helical gear needs to be supported by a ball bearing or a tapered roller bearing that can receive loads in both the radial direction and the thrust direction. In the in-wheel motor drive device 110 of FIG. 3, the output helical gear 140 has both a load in the thrust direction on the drive wheel 14 side and a load in the thrust direction on the opposite side to the drive wheel 14, In order to receive a radial load, it is supported by two tapered roller bearings 148. Therefore, the dimension of the parallel shaft gear reducer 120, for example, the dimension D2 from the wall surface on the drive wheel side of the second casing 126 that houses the electric motor 118 to the end surface on the electric motor side of the inner ring 150 of the wheel hub 122 is The length of the vehicle in-wheel motor drive device 110 is increased in the axial direction of the drive wheels 14. In the in-wheel motor drive device 10 of the present embodiment, the inner ring 50 is fastened to the output shaft 42 by the nut 66, so that the output shaft 42 is concentrically and integrally connected to the inner ring 50. As a result, the dimension of the parallel shaft type gear reducer 20, for example, the dimension D1 shown in FIG. 1 is shorter than the corresponding dimension D2 shown in FIG. It is downsized.

  As described above, according to the in-wheel motor drive device 10 of the present embodiment, (a) the electric motor 18 provided in the casing 24, and (b) the first rotation center line C1 are rotatably provided. An input helical gear 38 to which the rotation of the electric motor 18 is input is provided so as to be rotatable around a second rotational center line C2 parallel to the first rotational center line C1, and an output meshing with the input helical gear 38 is provided. A parallel-shaft gear reducer 20 that has a tooth gear 40 and an output shaft 42 to which the output helical gear 40 is fixed, decelerates the rotation of the electric motor 18 and outputs it from the output shaft 42; An inner ring 50 connected to the output shaft 42, an outer ring 52 fixed to the casing 24, and a spherical rolling element 54 provided between the inner ring 50 and the outer ring 52, a radial load and a thrust load Main bearing 60 receiving An in-wheel motor drive device 10 for driving the drive wheel 14 attached to the wheel hub 22 by the electric motor 18, provided with a wheel hub 22 that transmits the output from the output shaft 42 to the drive wheel 14. And (e) a cylindrical roller bearing 48 is provided between the helical gear 40 and the casing 24 so as to be within the tooth width B of the helical gear 40, and (f) the helical output. The radial load of the tooth gear 40 is received by the casing 24 via the cylindrical roller bearing 48. (g) The thrust load of the helical gear 40 is received by the casing 24 via the main bearing 60. .

  According to the in-wheel motor drive device 10 of this embodiment configured as described above, the radial load of the output helical gear 40 is received by the casing 24 via the cylindrical roller bearing 48, and the output helical gear. Since the load in the thrust direction of the gear 40 is received by the casing 24 via the main bearing 60, the output helical gear 40 is, for example, a ball bearing that can receive both radial and thrust loads. Since the structure around the output shaft 42 and the output helical gear 40 is simplified, the dimensions of the in-wheel motor drive device 10 in the axial direction of the drive wheel 14 are eliminated. Can be shortened, and the weight can be reduced. Further, since the cylindrical roller bearing 48 is accommodated in the tooth width B of the output helical gear 40, the dimension of the in-wheel motor drive device 10 in the axial direction of the drive wheel 14 can be shortened, and the weight can be reduced. You can also

  As mentioned above, although the Example of this invention was described in detail based on drawing, this invention is applied also in another aspect.

  For example, in the above-described embodiment, the main bearing 60 is a ball bearing. However, the main bearing 60 may be a tapered roller bearing as long as it can receive loads in both the radial direction and the thrust direction.

  In the above-described embodiment, the cylindrical roller bearing 48 supports the output helical gear 40. However, it is only necessary to receive a radial load, and for example, a ball bearing may be used.

  Further, a plurality of heat radiation fins for cooling the inside of the casing 24 may be provided on the outer surface of the casing 24.

  In the above-described embodiment, the in-wheel motor drive device 10 is provided in the EV vehicle. However, the in-wheel motor drive device 10 may be provided in a HEV vehicle (hybrid electric vehicle) or the like.

  It should be noted that the above description is merely an embodiment, and other examples are not illustrated. However, the present invention is implemented in variously modified and improved modes based on the knowledge of those skilled in the art without departing from the gist of the present invention. Can do.

10: In-wheel motor drive device for vehicle 14: Drive wheel 18: Electric motor 20: Parallel shaft type gear reducer 22: Wheel hub 24: Casing (non-rotating member)
38: input helical gear 40: output helical gear 42: output shaft 48: cylindrical roller bearing 50: inner ring 52: outer ring 54: spherical rolling element (rolling element)
60: main bearing B: tooth width C1: first rotation center line C2: second rotation center line

Claims (1)

An electric motor provided on the non-rotating member;
An input helical gear provided rotatably around the first rotation center line, to which rotation of the electric motor is input, provided rotatably around a second rotation center line parallel to the first rotation center line; An output helical gear that meshes with the input helical gear, and an output shaft to which the helical helical gear is fixed, and a parallel shaft type that decelerates the rotation of the electric motor and outputs from the output shaft A gear reducer,
An inner ring connected to the output shaft, an outer ring fixed to the non-rotating member, and a rolling element provided between the inner ring and the outer ring, and a radial load and a thrust load A wheel hub including a main bearing for receiving, and transmitting an output from the output shaft to a drive wheel;
An in-wheel motor drive device for a vehicle that drives the drive wheels attached to the wheel hub by the electric motor,
A cylindrical roller bearing is provided between the output helical gear and the non-rotating member so that the output helical gear is accommodated within a tooth width of the helical gear,
The radial load of the output helical gear is received by the non-rotating member via the cylindrical roller bearing,
A load in the thrust direction of the output helical gear is received by the non-rotating member via the main bearing.

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