JP7143748B2 - Vehicle driving device with steering function - Google Patents

Description

The present invention relates to a vehicle drive system with a steering function.

Patent Literature 1 discloses a steering device for an in-wheel motor vehicle that uses a steering actuator to rotate wheels around a vertical steering shaft provided on an upper arm.

Patent Document 2 discloses a structure in which one wheel and the other wheel connected to the wheel via a tie rod are steered by a steering force output from a steering wheel shaft and a power assist device.

Patent Document 3 discloses an electric motor having a stator fixed to a housing and a rotor rotatably supported with respect to the stator, a wheel drive unit that transmits the rotation of the rotor to an axle to rotationally drive a wheel, and a wheel A vehicle drive actuator including a steering angle control mechanism for steering braking is disclosed.

JP 2013-112112 A Japanese Patent No. 6273427 Japanese Patent No. 5239582

In any of the above-described conventional examples, a steering actuator is arranged near the wheel in addition to the drive motor for the wheel.

However, if such an actuator is provided on a drive wheel such as the front wheel of a front-wheel drive vehicle, it may be difficult to arrange the actuator due to interference with an axle or the like that transmits drive torque. In addition, in the configuration described in Patent Document 3, since a complicated planetary gear mechanism, clutches, and motors are arranged inside the wheel, the weight of the wheel increases, and there is concern that the unsprung weight increases and the ride comfort deteriorates. be done.

SUMMARY OF THE INVENTION It is an object of the present invention to implement driving and steering operations of wheels using a single motor as a driving source while suppressing an increase in the number of parts and weight in the wheels.

A vehicle drive device with a steering function according to a first aspect includes a drive motor, an input shaft driven by the motor, an output shaft that intersects the input shaft and to which wheels are attached, and an attached input gear, an output gear attached to the output shaft and meshing with the input gear and forming a first cross-axis gear together with the input gear; rotatably supporting the output shaft; It has a housing rotatably supported therearound, a first brake capable of restricting rotation of the output shaft, and a second brake capable of restricting rotation of the housing.

In this vehicle drive device with steering function, an input shaft to which an input gear is attached and an output shaft to which an output gear is attached intersect, and the input gear and the output gear are in mesh. That is, the input gear and the output gear constitute the first cross shaft gear. Rotation of the housing can be suppressed by using the second brake, and rotation of the output shaft can be suppressed by using the first brake.

Here, when the motor is operated to rotate the input gear while the second brake is used and the first brake is not used, the rotation is transmitted from the input gear to the output gear and the output shaft rotates. At this time, rotation of the housing is suppressed. Therefore, when the second brake is used and the first brake is not used, the power of the motor can be distributed mainly to the driving torque of the wheels.

On the other hand, when the motor is operated to rotate the input gear while the first brake is used without using the second brake, the rotation of the wheels is suppressed because the rotation of the output gear is suppressed. However, since the input gear and output gear are in mesh, the output gear, output shaft and housing rotate about the input shaft, resulting in steering of the wheels. Therefore, when the second brake is not used and the first brake is used, the power of the motor can be distributed mainly to the steering torque of the wheels.

By controlling the braking force of the second brake and the braking force of the first brake, it is possible to arbitrarily change the distribution of the power of the motor between the driving torque of the wheels and the steering torque. Crabs can also be allocated 100%.

A second aspect is the vehicle drive device with a steering function according to the first aspect, wherein the motor, the input shaft, the output shaft, the input gear, the output gear, the housing, the first brake and the first 2 brakes are provided on the left and right wheels of the vehicle, respectively, the left and right housings are connected by tie rods, and depending on the steering conditions, the driving torque that rotates the output shaft by the motor and the left and right motors are applied. A steering torque for rotating the housing can be adjusted.

In this vehicle drive device with a steering function, the left and right wheels are connected by a tie rod, so when one wheel is steered, the other wheel is also steered. Even if one of the left and right motors fails, the other motor can drive and steer the wheels, enabling avoidance driving to the evacuation area.

A third aspect is the vehicle drive device with a steering function according to the first aspect or the second aspect, wherein a second cross shaft gear is provided between the motor and the input shaft.

In this vehicle drive device with steering function, in addition to the first cross-axis gear composed of the input gear and the output gear, the second cross-axis gear is provided between the motor and the input shaft. can increase the degree of freedom of arrangement.

According to the vehicle drive device with a steering function according to the present invention, it is possible to realize the operation of driving and steering the wheels using a single motor as a drive source while suppressing the increase in the parts and weight in the wheels. .

1 is a plan view showing an example in which a vehicle drive system with a steering function according to the present embodiment is applied to front wheels of a vehicle; FIG. 1 is a cross-sectional view showing an example in which a vehicle drive system with a steering function according to the present embodiment is applied to front wheels of a vehicle; FIG. 1 is a cross-sectional view showing a vehicle drive system with a steering function according to this embodiment; FIG. (A) is a partial cross-sectional plan view showing a state in which wheels are driven in the vehicle drive system with a steering function according to the present embodiment. (B) is a partial cross-sectional plan view showing a state in which wheels are steered in the vehicle drive system with a steering function according to the present embodiment. (A) is a plan view schematically showing a state in which the vehicle is traveling straight. (B) is a plan view schematically showing a state in which the vehicle turns left due to a large steering input. (C) is a plan view schematically showing a state in which the vehicle turns left due to a small steering input.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments for carrying out the present invention will be described based on the drawings. In the drawings, arrow FR indicates the front of the vehicle, arrow UP indicates the upper direction of the vehicle, and arrow LH indicates the left direction of the vehicle.

1, 2, and 5, a vehicle drive system 10 with a steering function according to the present embodiment is provided for a left front wheel 14 and a right front wheel 24 of a vehicle 12 as an example of wheels. This vehicle drive device 10 with a steering function includes a driving motor 16, an input shaft 18, an output shaft 20, an input gear 28, an output gear 30, a housing 22, a first brake 31, a second and a brake 32 . The input gear 28 and the output gear 30 constitute a first cross shaft gear 41 .

The input shaft 18 is a rotating shaft driven by the motor 16 . As shown in FIGS. 2 and 3, the input shaft is supported by an arbitrary number of bearings 34 such that its axial direction is the vertical direction of the vehicle. The bearing 34 is provided on the support portion 36 . The support portion 36 is provided on the vehicle body 40, for example. A second cross shaft gear 42 is provided between the motor 16 and the input shaft 18 .

The motor 16 is attached to, for example, the vehicle body 40 so that the axial direction of the output shaft 46 is horizontal. A small gear 48 is attached to the output shaft 46 . A large gear 50 is attached to the upper end of the input shaft 18 . The small gear 48 and the large gear 50 constitute the second cross shaft gear 42 . In the illustrated example, the output shaft 46 to which the pinion gear 48 is attached and the input shaft 18 to which the large gear 50 is attached are orthogonal, and the crossing angle of the gear axes is 90°. Therefore, the second cross-axis gear 42 is an orthogonal axis gear. Also, the second cross shaft gear 42 is a reduction gear mechanism, and the number of teeth of the large gear 50 is set larger than the number of teeth of the small gear 48 .

In FIG. 3, a gear 50 is rotatably supported by a housing 52 via bearings 54 . An output shaft 46 of the motor 16 is rotatably supported by the housing 52 via bearings 56 . Although the housing 52 is provided in the vehicle body 40, illustration of the housing 52 is omitted in FIGS.

Output shaft 20 intersects input shaft 18 . A left front wheel 14 as an example of a wheel is attached to the output shaft 20 . The input gear 28 is attached to, for example, the lower end of the input shaft 18 . The output gear 30 is attached to the output shaft 20 and meshes with the input gear 28 to form a first cross shaft gear 41 together with the input gear 28 . In the illustrated example, the input shaft 18 to which the input gear 28 is attached and the output shaft 20 to which the output gear 30 is attached are perpendicular to each other, and the crossing angle of the gear axes is 90°. Therefore, the first cross-axis gear 41 is an orthogonal axis gear. Also, the first cross shaft gear 41 is a reduction gear mechanism, and the number of teeth of the output gear 30 is set larger than the number of teeth of the input gear 28 .

The housing 22 rotatably supports the output shaft 20 and is rotatably supported around the input shaft 18 . In the illustrated example, the output gear 30 attached to the output shaft 20 is rotatably supported by the housing 22 via bearings 58 . The housing 22 is rotatably supported coaxially with the input shaft 18 via a bearing 60 by a housing 52 on the vehicle body 40 side. The housing 22 also rotatably supports the input shaft 18 via bearings 62 . That is, the input shaft 18 is rotatably supported at two points by the bearings 34 and 62 arranged vertically.

The first brake 31 is provided on the housing, for example, and applies a braking force to the output gear 30 to limit the rotation of the output shaft 20 . The second brake 32 is provided on the housing 52 on the vehicle body 40 side, for example, and is capable of restricting the rotation of the housing 22 by applying a braking force to the housing 22 .

The structure of the first brake 31 and the second brake 32 is arbitrary, but mechanical brakes that generate braking force using frictional force, electrical brakes that generate braking force by consuming electrical energy, and fluid resistance are used. It is possible to use a configuration such as a fluid brake that generates a braking force by

Elements such as the motor 16, the input shaft 18, the output shaft 20, the input gear 28, the output gear 30, the housing 22, the first brake 31, the second brake 32, etc. 14 and right front wheel 24, respectively. The left and right housings 22 are connected by tie rods 44 . Specifically, the tie rod 44 is coupled to the left and right housings 22 at tie rod ends 44A at both ends. The tie rod end 44A is, for example, a ball joint.

In the vehicle drive device 10 with a steering function, the driving torque for rotating the output shaft 20 by the motor 16 in the state shown in FIG. 4A and the driving torque by the motor 16 shown in FIG. A steering torque for rotating the housing 22 can be adjusted.

(Action)
This embodiment is configured as described above, and the operation thereof will be described below. 3, in the vehicle drive device 10 with a steering function according to the present embodiment, an input shaft 18 having an input gear 28 and an output shaft 20 having an output gear 30 intersect each other. and the output gear 30 are in mesh. That is, the input gear 28 and the output gear 30 constitute the first cross shaft gear 41 . By using the second brake 32, rotation of the housing 22, that is, steering of the wheels can be suppressed. Further, by using the first brake 31, rotation of the output shaft 20, that is, driving of the wheels can be suppressed.

In addition to the first cross-axis gear 41 composed of the input gear 28 and the output gear 30, the second cross-axis gear 42 is provided between the motor 16 and the input gear 28. degree of freedom can be increased.

Here, when the motor 16 is operated to rotate the input gear 28 while the second brake 32 is used and the first brake 31 is not used, the output from the input gear 28 is shown in FIG. 5(A). Rotation is transmitted to the gear 30 and the output shaft 20 rotates. At this time, the rotation of the housing 22 is suppressed. Therefore, when the second brake 32 is used and the first brake 31 is not used, the power of the motor 16 can be distributed mainly to the driving torque of the left front wheel 14 (wheel), for example.

On the other hand, when the motor 16 is operated to rotate the input gear 28 while the first brake 31 is used and the second brake 32 is not used, the output gear 30 rotates as shown in FIG. is suppressed, for example, the rotational drive of the left front wheel 14 (wheel) is suppressed. However, since the input gear 28 and the output gear 30 are meshed, the output gear 30, the output shaft 20 and the housing 22 rotate around the input shaft 18, and as a result the left front wheel 14 (wheel) is steered ( angle θ). Therefore, when the second brake 32 is not used and the first brake 31 is used, the power of the motor 16 can be mainly distributed to the steering torque of the left front wheel 14 as an example of wheels.

In addition, by controlling the braking force of the second brake 32 and the braking force of the first brake 31, the power of the motor 16 can be arbitrarily changed in the distribution of the drive torque and steering torque of the left front wheel 14 as an example of a wheel. 100% can be distributed to either the drive torque or the steering torque. In other words, two degrees of freedom (driving and steering of the wheels) can be realized.

Furthermore, as shown in FIG. 1, in the present embodiment, the left front wheel 14, which is an example of left and right wheels, is connected by the tie rod 44. Therefore, when one wheel, the right front wheel 24, is steered, the other wheel is steered. The left front wheel 14, which is the wheel of the left front wheel, is also steered in conjunction with it. Even if one of the left and right motors 16 fails, the other motor 16 can drive and steer the wheels, enabling avoidance driving to the evacuation area.

As described above, according to the present embodiment, it is possible to realize the driving and steering operation of the wheels using the single motor 16 as a drive source while suppressing the increase in the number of components and the weight in the wheels.

(vehicle movement)
Here, an example of basic operation of the vehicle 12 will be described with reference to FIG. The vehicle 12 is front-wheel drive, and the vehicle drive device 10 with a steering function is applied to the left front wheel 14 and the right front wheel 24, respectively. The operating conditions are as shown in Table 1. In Table 1, "ON" means activated, "NE" means activated on demand, and "OFF" means not activated. "Power running" of a motor means a state in which electric power is converted into rotation of the output shaft of the motor and output, and "regeneration" indicates a state in which rotation of the output shaft of the motor is converted into electric power.

(a) Straight Mode When the vehicle travels straight, the left front wheel and the right front wheel are not steered because the second brakes are applied to the left front wheel and the right front wheel, respectively. During acceleration, the same driving torque is applied by the motor to the left front wheel and the right front wheel. Also, during deceleration, the braking force of the first brake acts on the front left wheel and the front right wheel. Further, braking force due to regeneration of the motor during deceleration also acts on the left front wheel and the right front wheel.

(b) Right-left turn mode When a large steering angle is input in the left-turn direction by steering operation of the vehicle or the like, the first brake for the right front wheel is actuated to suppress the drive of the right front wheel, and the right front wheel is turned. steered to the left. This motion is also transmitted to the left front wheel via the tie rod, so that the left front wheel is also steered to the left. At this time, the motor for the left front wheel and the second brake do not operate. The first brake for the left front wheel may or may not operate. On the other hand, in the case of a right turn, the first brake for the left front wheel is actuated, thereby suppressing the driving of the left front wheel and steering the left front wheel to the right. This motion is also transmitted to the right front wheel via the tie rod, so that the right front wheel is also steered to the right. At this time, the motor for the right front wheel and the second brake do not operate. The first brake for the right front wheel may or may not operate. In this way, in the case of left and right turns, the motors of the outer wheels as viewed from the turning center are driven, and the motors of the inner wheels are not driven. The inside wheels may or may not be braked as desired.

(c) Turning Mode A turning mode (torque vectoring mode) is entered when a small steering angle is input in the left-turn direction by steering operation of the vehicle or the like. Specifically, since the second brakes are applied to the front left wheel and the front right wheel, neither the front left wheel nor the front right wheel is steered. Then, a difference is given to the driving torque of the motor between the right front wheel and the left front wheel. Specifically, the drive torque of the right front wheel is made larger than the drive torque of the left front wheel. Due to this difference in drive torque, a counterclockwise turning torque T (yaw) is generated in a plan view of the vehicle, causing the vehicle to turn left.

On the other hand, when a small steering angle is input in the right turn direction, the drive torque for the left front wheel is made larger than the drive torque for the right front wheel. Due to this difference in driving torque, a turning torque (yaw) is generated in a clockwise direction in a plan view of the vehicle, causing the vehicle to turn right. In this turning mode, the same operation is possible even when the second brake is not turned ON (not operated). That is, the steering used in the right/left turn mode can be added according to the torque difference between the left and right wheels.

This turning mode is suitable when a steering angle of, for example, less than 3° is sufficient, such as when changing course while traveling at high speed. Mode switching between (b) and (c) is performed based on inputs from the steering angle, vehicle speed, accelerator pedal, and brake pedal.

In the example of FIG. 5, the case where the vehicle 12 has a front-wheel drive and front-wheel steering configuration has been described. Embodiments can be applied. The present embodiment can also be applied to a four-wheel drive vehicle (not shown).

[Other embodiments]
An example of the embodiment of the present invention has been described above, but the embodiment of the present invention is not limited to the above, and can be modified in various ways without departing from the spirit of the present invention. Of course there is.

The vehicle drive device 10 with a steering function is not limited to being provided on the left and right wheels of a four-wheeled vehicle, and may be provided on one wheel like the front wheel of a three-wheeled vehicle.

Further, although the second cross-axis gear 42 is provided between the motor 16 and the input shaft 18, the second cross-axis gear 42 may be omitted. Also, another reduction gear mechanism may be provided between the motor 16 and the input shaft 18 . Furthermore, the motor 16 may be directly connected to the input shaft 18 .

Both the first cross shaft gear 41 and the second cross shaft gear 42 are not limited to orthogonal shaft gears. For example, the crossing angle of the gear shafts may be 90±10°.

10 Vehicle drive device with steering function 12 Vehicle 14 Left front wheel (wheel)
16 motor 18 input shaft 20 output shaft 22 housing 24 right front wheel (wheel)
28 input gear 30 output gear 31 first brake 32 second brake 41 first cross shaft gear 42 second cross shaft gear 44 tie rod

Claims (3)

a driving motor;
an input shaft driven by the motor;
an output shaft intersecting the input shaft and having wheels mounted thereon;
an input gear attached to the input shaft;
an output gear attached to the output shaft and meshing with the input gear, forming a first cross-axis gear together with the input gear;
a housing that rotatably supports the output shaft and is rotatably supported around the input shaft;
a first brake capable of limiting rotation of the output shaft;
a second brake capable of restricting rotation of the housing;
A vehicle drive device with a steering function. The motor, the input shaft, the output shaft, the input gear, the output gear, the housing, the first brake, and the second brake are provided on left and right wheels of the vehicle, respectively,
The left and right housings are connected by tie rods,
2. The steering function-equipped vehicle according to claim 1, wherein the drive torque for rotating the output shaft by the motor and the steering torque for rotating the housing by the left and right motors can be adjusted according to steering conditions. vehicle drive. 3. The vehicle driving device with steering function according to claim 1, further comprising a second cross shaft gear provided between said motor and said input shaft.

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