JP6903534B2 - In-wheel motor drive - Google Patents

Description

The present invention relates to, for example, an in-wheel motor drive device in which a rotational driving force of an electric motor is input to a speed reducer to reduce the rotation speed and transmit it to a wheel bearing.

As a conventional in-wheel motor drive device, for example, there is a device having a structure disclosed in Patent Document 1.

The in-wheel motor drive device of Patent Document 1 includes an electric motor that generates a driving force for the wheels and a speed reducer that decelerates and outputs the rotation of the electric motor, and rotationally drives the wheels by the rotational output of the electric motor. It is configured to do.

This in-wheel motor drive device has a structure in which an electric motor and a speed reducer are integrally housed in a casing.

The casing is provided with a terminal box for connecting a power line extending from an external power source for supplying electric power to the electric motor.

This terminal box has a structure in which a lead wire extending from an electric motor built in a casing and a power line extending from an external power source are electrically connected.

Japanese Unexamined Patent Publication No. 2015-160529

By the way, some conventional in-wheel motor drive devices include, for example, a terminal box 154 as shown in FIG. 7. The reference numeral M in the figure indicates the inner diameter of the wheel, and the casing 125 is housed in the wheel space m.

The terminal box 154 is integrally provided on the outer periphery of the motor housing 155 of the casing 125. The terminal box 154 has three terminal portions 156 to which a lead wire (not shown) extending from an electric motor built in the motor housing 155 is connected. Three power lines 153 extending from an external power source are electrically connected to the terminal portion 156.

The three terminal portions 156 of the terminal box 154 are arranged in a straight line along the front-rear direction of the vehicle from the viewpoint of standardization of terminal parts and workability. Therefore, since it is necessary to secure a creepage distance between adjacent terminal portions 156, the terminal box 154 becomes larger in the vehicle front-rear direction.

Here, since a damper (not shown) is arranged above the vehicle at the axle center 164, the terminal box 154 cannot be enlarged toward the rear side of the vehicle (closer to the axle). As a result, the terminal box 154 has to be enlarged toward the front side of the vehicle.

When the terminal box 154 is enlarged toward the front side of the vehicle in this way, it interferes with the wheel adjacent to the terminal box 154. In order to avoid interference with this wheel, it is necessary to increase the diameter of the wheel.

Increasing the diameter of this wheel increases the unsprung weight, lowers the running stability and NVH characteristics of the vehicle, and causes deterioration of ride quality.

Therefore, the present invention has been proposed in view of the above-mentioned problems, and an object of the present invention is to provide an in-wheel motor drive device capable of making a terminal box compact by a simple structure.

The in-wheel motor drive device according to the present invention includes an electric motor for driving wheels, a speed reducer that decelerates and outputs the rotation of the electric motor, a wheel bearing that transmits the output of the speed reducer to the wheels, and an electric motor. It is provided with a casing for accommodating the motor, and has a structure in which a terminal box for connecting a plurality of power lines to the electric motor is arranged in the casing.

As a technical means for achieving the above-mentioned object, the terminal box of the present invention has a plurality of terminal portions for connecting a power line to a lead wire extending from an electric motor to a casing, and the terminal portions are arranged in a staggered pattern. It is characterized by having done it.

In the present invention, by arranging the plurality of terminal portions in a staggered pattern, it is possible to make the terminal box compact while ensuring the creepage distance between adjacent terminal portions.

As a result, it is possible to avoid increasing the diameter of the wheel, and by suppressing the increase in unsprung weight, it is possible to prevent deterioration of the running stability and NVH characteristics of the vehicle and deterioration of riding comfort.

The terminal portion in the present invention preferably has a structure in which an insulating terminal block is attached to a casing and the connection end portion of the power line is screwed to the connection end portion of the lead wire led out from the terminal block.

If such a structure is adopted, it becomes easy to secure a creepage distance between adjacent terminal portions in a plurality of terminal portions composed of both connection ends of the lead wire and the power line.

It is desirable that the terminal box in the present invention has a structure in which a part of the outer peripheral portion of the casing is integrally projected outward in the radial direction, and the terminal portion is provided on the axial end surface of the terminal box.

If such a structure is adopted, it becomes easy to avoid increasing the diameter of the wheel by making the terminal box compact.

According to the present invention, the terminal box can be made compact while ensuring the creepage distance between adjacent terminal portions. As a result, it is possible to avoid increasing the diameter of the wheel, and by suppressing the increase in unsprung weight, it is possible to prevent deterioration of the running stability and NVH characteristics of the vehicle and deterioration of riding comfort. As a result, a high-performance in-wheel motor drive device can be provided.

It is sectional drawing which shows the whole structure of the in-wheel motor drive device in embodiment of this invention. It is a front view which looked at the in-wheel motor drive device of FIG. 1 from the vehicle (in-board) side. It is an enlarged front view which shows the terminal box of FIG. It is an enlarged front view which shows the terminal box in another embodiment of this invention. It is a top view which shows the schematic structure of the electric vehicle equipped with the in-wheel motor drive device. It is a rear sectional view which shows the electric vehicle of FIG. It is a front view which looked at the conventional in-wheel motor drive device from the vehicle (in-board) side.

An embodiment of the in-wheel motor drive device according to the present invention will be described in detail with reference to the drawings. FIG. 5 is a schematic plan view of the electric vehicle 11 equipped with the in-wheel motor drive device 21, and FIG. 6 is a schematic cross-sectional view of the electric vehicle 11 as viewed from the rear.

As shown in FIG. 5, the electric vehicle 11 includes a chassis 12, front wheels 13 as steering wheels, rear wheels 14 as drive wheels, and an in-wheel motor drive device 21 that transmits driving force to the rear wheels 14. Equip. As shown in FIG. 6, the rear wheel 14 is housed inside the wheel housing 15 of the chassis 12, and is fixed to the lower part of the chassis 12 via an independent suspension device (suspension) 16.

The electric vehicle 11 is provided with an in-wheel motor drive device 21 for driving the left and right rear wheels 14 inside the wheel housing 15, so that it is not necessary to provide a motor, a drive shaft, a differential gear mechanism, or the like on the chassis 12. .. As a result, there is an advantage that a large cabin space can be secured and the rotation of the left and right rear wheels 14 can be controlled respectively.

It is necessary to suppress the unsprung weight in order to improve the running stability and NVH characteristics of the electric vehicle 11, and further, it is required to reduce the size of the in-wheel motor drive device 21 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. As a result, a compact in-wheel motor drive device 21 is realized, and by suppressing the unsprung weight, an electric vehicle 11 having excellent running stability and NVH characteristics is obtained.

Before explaining 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 body, the side closer to the outside of the vehicle body 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). It is called.

As shown in FIG. 1, the in-wheel motor drive device 21 includes an electric motor 22 for driving wheels, a parallel shaft gear reducer 23 for decelerating and outputting the rotation of the electric motor 22, and a parallel shaft gear reducer 23 thereof. It includes a wheel bearing 24 that transmits the output of 23 to the rear wheels 14 (see FIGS. 5 and 6), which are driving wheels.

In this embodiment, the radial gap type electric motor 22 is illustrated, but other electric motors such as the axial gap type may be used. Further, although the parallel shaft gear reducer 23 is illustrated, other speed reducers such as a planetary gear reducer and a cycloid speed reducer may be used.

The electric motor 22 and the parallel shaft gear reducer 23 are housed in the casing 25. The casing 25 in which the electric motor 22 and the parallel shaft gear reducer 23 are housed is mounted in the wheel housing 15 (see FIG. 6) of the electric vehicle 11.

The electric motor 22 is integrally rotated with the stator 26 fixed to the casing 25, the rotor 27 arranged so as to face each other radially inside the stator 26 with a gap, and the rotor 27 arranged radially inside the rotor 27. The motor rotating shaft 28 is provided.

The motor rotating shaft 28 can rotate at high speed at about 10,000 to several thousand rotations per minute. The stator 26 is configured by winding a coil around the outer circumference of the magnetic core. A permanent magnet or a magnetic material is arranged inside the rotor 27.

The motor rotating shaft 28 holds the rotor 27 by a holder portion 29 that extends integrally outward in the radial direction. The holder portion 29 has a structure in which a concave groove into which the rotor 27 is fitted and fixed is formed in an annular shape. The motor rotating shaft 28 is rotatably supported with respect to the casing 25 by rolling bearings 30 and 31.

The parallel shaft gear reducer 23 includes an input gear 32, an intermediate gear 33, and an output gear 34. The intermediate gear 33 coaxially has a large-diameter tooth portion 35 on the inboard side and a small-diameter tooth portion 36 on the outboard side.

In the parallel shaft gear reducer 23, the tooth portion 37 of the input gear 32 and the large diameter tooth portion 35 of the intermediate gear 33 mesh with each other, and the small diameter tooth portion 36 of the intermediate gear 33 and the tooth portion 38 of the output gear 34 mesh with each other. As a result, the rotation of the electric motor 22 is decelerated with a predetermined reduction ratio.

Since the in-wheel motor drive device 21 is housed inside the wheel housing 15 (see FIG. 6) and has an unsprung weight, it is essential to reduce the size and weight. Therefore, by using the parallel shaft gear reducer 23 having a large reduction ratio, the electric motor 22 can be miniaturized by combining with the high-speed rotating electric motor 22, and the compact and high reduction ratio in-wheel motor drive device 21 can be used. Realize.

The input gear 32 is coaxially attached to the motor rotating shaft 28 by spline fitting. The input gear 32, the intermediate gear 33, and the output gear 34 are rotatably supported by the casing 25 by rolling bearings 39 to 44. The output gear 34 is coaxially attached to the hub wheel 46 of the wheel bearing 24 by spline fitting.

Here, helical gears are used for the input gear 32, the intermediate gear 33, and the output gear 34. Helical gears are effective in that the number of teeth that mesh with each other increases at the same time and the tooth contact is dispersed, so that the sound is quiet and the torque fluctuation is small.

In this way, by using a helical gear for the parallel shaft gear reducer 23, it is possible to realize an in-wheel motor drive device 21 that is easy to manufacture, can reduce costs, and is quiet and efficient in terms of performance. it can.

The wheel bearing 24 includes an outer ring 45 fixed to the casing 25, an inner ring 47 press-fitted into the hub ring 46 and the hub ring 46 arranged inside the outer ring 45, and the hub ring 46, the inner ring 47, and the outer ring 45. The main part is composed of a plurality of rolling elements 48 arranged between them.

Preload is applied to the wheel bearing 24 by crimping the inboard side end of the hub wheel 46. By applying this preload, the wheel bearing 24 has a double-row angular contact ball bearing structure.

A shaft portion 50 extending integrally from the output gear 34 of the parallel shaft gear reducer 23 to the outboard side is coupled to the shaft hole 49 of the hub wheel 46 of the wheel bearing 24 so that torque can be transmitted by spline fitting. ..

Seal members 51 are provided at both ends of the wheel bearing 24 in the axial direction in order to prevent the intrusion of muddy water and the like and prevent the leakage of grease.

A flange 52 is integrally formed on the outboard side of the hub wheel 46, and the rear wheel 15 (see FIGS. 5 and 6) is connected to the flange 52 by a hub bolt 53.

In the in-wheel motor drive device 21 having the above configuration, the rotation of the electric motor 22 is decelerated by the input gear 32, the intermediate gear 33, and the output gear 34 of the parallel shaft gear reducer 23, and is transmitted to the wheel bearing 24.

In this way, the rotation of the electric motor 22 is decelerated by the parallel shaft gear reducer 23 and transmitted to the wheel bearings 24. Therefore, even when the low torque and high speed rotation type electric motor 22 is adopted, the rear wheels 14 ( It is possible to transmit the torque required for (see FIGS. 5 and 6).

In the in-wheel motor drive device 21, lubricating oil for cooling the electric motor 22 and cooling and lubricating the parallel shaft gear reducer 23 is sealed in the casing 25.

The lubricating oil cools the electric motor 22 by the rotation of the rotor 27, and cools and lubricates the parallel shaft gear reducer 23 by the bouncing by the rotation of the input gear 32, the intermediate gear 33, and the output gear 34.

The overall configuration of the in-wheel motor drive device 21 in this embodiment is as described above, but its characteristic configuration will be described in detail below.

As shown in FIG. 2, a power line extending from an external power source (not shown) to supply electric power to the electric motor 22 in a casing 25 accommodating an electric motor 22 and a parallel shaft gear reducer 23 (see FIG. 1). A terminal box 54 for connecting the 63 is provided. The reference numeral M in the figure indicates the inner diameter of the wheel, and the casing 25 is housed in the wheel space m.

The in-wheel motor drive device 21 includes a parallel shaft gear reducer 23 in which the axle center 64 and the motor shaft center 62 are offset in the vehicle front-rear direction. Reference numeral 65 in the drawing is a speed reducer housing for accommodating the parallel shaft gear speed reducer 23.

The terminal box 54 is integrally provided on the upper part of the outer circumference of the motor housing 55 of the casing 25 so as to project outward in the radial direction. On the axial end surface of the terminal box 54, three terminal portions 56 are provided from which a lead wire extending from an electric motor 22 (see FIG. 1) built in the motor housing 55 is led out. Three power lines 63 extending from an external power source (not shown) are electrically connected to the terminal portion 56.

In this embodiment, as shown in FIG. 2, the case where the terminal portion 56 of the terminal box 54 is arranged on the inboard side of the motor housing 55 is illustrated, but it is arranged on the outboard side of the motor housing 55. It is also possible to set it up.

The three terminal portions 56 of the terminal box 54 are provided with a teardrop-shaped insulating terminal block 57. The small diameter portion 58 of the terminal block 57 is fixed to the casing 25 by screwing or the like. The large diameter portion 59 of the terminal block 57 is formed with a small hole through which the connection end portion 60 of the lead wire extending from the electric motor 22 is inserted. The connection end 60 of the lead wire inserted through the small hole is led out to the outside.

On the other hand, a crimp terminal is attached to the connection end 61 of the power line 63 extending from the external power source by crimping. A small hole through which the connection end 60 of the lead wire is inserted is formed at the tip of the crimp terminal. A screw is engraved on the connecting end 60 of the lead wire.

In the terminal portion 56 having the above configuration, the crimp terminal of the connection end portion 61 of the power line 63 is inserted into the connection end portion 60 of the lead wire led out from the small hole of the terminal block 57 attached to the casing 25. A nut member (not shown) is screwed onto the connection end 60 of the lead wire and tightened and fixed.

As a result, the connection end 60 of the lead wire and the connection end 61 of the power line 63 are electrically connected. In this way, the terminal portion 56 is composed of both connection end portions 60 and 61 of the lead wire and the power line 63. Hereinafter, both connection end portions 60 and 61 of the lead wire and the power line 63 will be referred to as terminal portions 56.

The terminal box 54 of this embodiment has a structure in which three terminal portions 56 are arranged in a staggered pattern. That is, as shown in the enlarged view of FIG. 3, the terminal block 57 of the terminal portion 56 located at the center is arranged with the small diameter portion 58 facing down and the large diameter portion 59 facing up. On the other hand, the terminal blocks 57 of the terminal portions 56 located on the left and right sides are arranged with the small diameter portion 58 facing up and the large diameter portion 59 facing down.

With such an arrangement, the terminal portions 56, which are the connection end portions 60 and 61 of the lead wire and the power line 63, are arranged in a staggered shape (triangular shape). By arranging the three terminal portions 56 in a staggered manner by shifting them in the vertical direction of the vehicle in this way, the terminal box 54 can be made compact while ensuring the creepage distance between the adjacent terminal portions 56.

That is, the terminal portion 56 located in the center is arranged on the upper side of the vehicle, and the terminal portions 56 located on the left and right are arranged on the lower side of the vehicle to form a staggered shape, thereby ensuring the creepage distance between the adjacent terminal portions 56. can do.

In particular, the terminal portion 56 located on the left side can be shifted to the lower side of the vehicle more than the terminal portion 56 located on the right side. This is because the terminal portion 56 located on the left side is farther from the center 62 of the motor shaft in the front-rear direction of the vehicle than the terminal portion 56 located on the right side on the outer periphery of the motor housing 55.

Therefore, the creepage distance between the terminal portion 56 located at the center and the terminal portion 56 located on the left side is larger than the creepage distance between the terminal portion 56 located at the center and the terminal portion 56 located on the right side. As a result, it becomes easy to secure the creepage distance between the terminal portions 56.

As described above, the terminal box 54 can be reduced in the front-rear direction of the vehicle while ensuring the creepage distance between the adjacent terminal portions 56. That is, the terminal box 54 (see FIG. 2) can be made smaller than the conventional terminal box 154 (see FIG. 7) on the front side of the vehicle (L1 <L2).

By making the terminal box 54 smaller on the front side of the vehicle in this way, it is possible to avoid interference between the terminal box 54 and the wheel. As a result, it is possible to avoid increasing the diameter of the wheel, and by suppressing the increase in unsprung weight, it is possible to prevent deterioration of the running stability and NVH characteristics of the vehicle and deterioration of riding comfort.

In the above embodiment, a structure in which the three terminal portions 56 are arranged in a triangular shape has been illustrated, but the present invention is not limited to this, and as shown in FIG. 4, the three terminal portions 56 are reversed. It may be arranged in a triangular shape.

That is, in the terminal box 54 of the embodiment shown in FIG. 4, the terminal block 57 of the terminal portion 56 located at the center is arranged with the small diameter portion 58 facing up and the large diameter portion 59 facing down. There is. On the other hand, the terminal blocks 57 of the terminal portions 56 located on the left and right sides are arranged with the small diameter portion 58 facing down and the large diameter portion 58 facing up.

With such an arrangement, the terminal portions 56, which are the connection end portions 60 and 61 of the lead wire and the power line 63, are arranged in a staggered shape (inverted triangular shape). By arranging the three terminal portions 56 in a staggered manner by shifting them in the vertical direction of the vehicle in this way, the terminal box 54 can be made compact while ensuring the creepage distance between the adjacent terminal portions 56.

That is, the terminal portion 56 located in the center is arranged on the lower side of the vehicle, and the terminal portions 56 located on the left and right are arranged on the upper side of the vehicle to form a staggered shape, thereby ensuring the creepage distance between the adjacent terminal portions 56. can do.

As described above, the terminal box 54 can be reduced in the front-rear direction of the vehicle while ensuring the creepage distance between the adjacent terminal portions 56. That is, by making the terminal box 54 smaller on the front side of the vehicle, it is possible to avoid interference between the terminal box 54 and the wheel.

As a result, it is possible to avoid increasing the diameter of the wheel, and by suppressing the increase in unsprung weight, it is possible to prevent deterioration of the running stability and NVH characteristics of the vehicle and deterioration of riding comfort.

In the above embodiments, as shown in FIGS. 5 and 6, the electric vehicle 11 having the rear wheels 14 as the driving wheels has been illustrated, but the front wheels 13 may be the driving wheels, or a four-wheel drive vehicle may be used. .. In the present specification, the term "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 it goes without saying that the present invention can be carried out in various forms without departing from the gist of the present invention. Indicated by the scope of the claim and further includes the equal meaning described in the claims, and all modifications within the scope.

21 In-wheel motor drive device 22 Electric motor 23 Reducer (parallel shaft gear reducer)
24 Wheel bearings 54 Terminal box 55 Casing (motor housing)
56 Terminal part 57 Terminal block 60 Leader wire connection end 61 Power line connection end 63 Power line

Claims (3)

Accommodates an electric motor that drives wheels that can rotate around an axle, a speed reducer that decelerates and outputs the rotation of the electric motor, wheel bearings that transmit the output of the speed reducer to the wheels, and the electric motor. An in-wheel motor drive device in which a terminal box for connecting a plurality of power lines to the electric motor is provided in the casing.
The speed reducer is composed of a parallel shaft gear speed reducer.
The terminal box has a plurality of terminals for connecting the power line to the lead wire extending from said electric motor to said casing, a plurality of terminal portions, when viewed from the direction in which the axle extends, in the vertical direction of the vehicle An in-wheel motor drive unit characterized by being staggered and arranged in a staggered pattern. The in-wheel according to claim 1, wherein the terminal portion has a structure in which an insulating terminal block is attached to a casing and a connection end portion of a power line is screwed to a connection end portion of a lead wire led out from the terminal block. Motor drive. The inn according to claim 1 or 2, wherein the terminal box has a structure in which a part of the outer peripheral portion of the casing is integrally projected outward in the radial direction, and the terminal portion is provided on the axial end surface of the terminal box. Wheel motor drive.

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