Wheel steering device

1. A wheel steering device of a steer-by-wire configuration for a vehicle, comprising:

a steering knuckle that constitutes a part of a suspension device and that is capable of moving relative to a body of the vehicle in an up-down direction, the steering knuckle holding a wheel such that the wheel is rotatable; and

a steering actuator configured to cause the steering knuckle to be pivoted about a kingpin axis to steer the wheel, the steering actuator being disposed on a lower arm and having an actuator arm configured to pivot the steering knuckle,

wherein a caster angle and a caster offset are both 0,

wherein the wheel steering device is configured to enable the wheel to be steered based on an operation of an operating member by a driver of the vehicle, and

wherein the wheel steering device is used with a reaction-force applying device configured to controllably apply an operation reaction force to the operating member.

2. The wheel steering device according to claim 1 , wherein the steering knuckle is supported by the body of the vehicle through the lower arm, the lower arm constitutes the suspension device and that is pivotable relative to the body of the vehicle about a horizontal pivot axis.

3. The wheel steering device according to claim 1 , wherein the steering actuator enables the wheel to be steered independently of other wheels of the vehicle.

4. The wheel steering device according to claim 3 , wherein a kingpin offset is 0.

5. The wheel steering device according to claim 3 , wherein the steering knuckle is supported by the body of the vehicle through the lower arm, the lower arm constitutes the suspension device, and the steering actuator is disposed on the lower arm.

6. The wheel steering device according to claim 1 , wherein the steering actuator includes an electric motor as a drive source.

7. The wheel steering device according to claim 6 , further comprising a controller configured to control a supply current to the electric motor based on a deviation of a steering angle of the wheel with respect to a target steering angle.

8. The wheel steering device according to claim 7 , wherein the controller is configured to determine the target steering angle based on an operation of an operating member by a driver of the vehicle.

9. A wheel mounting module for mounting a wheel on a body of a vehicle, comprising:

a suspension device including a lower arm and a carrier supported by the lower arm and rotatably holding the wheel, the carrier being capable of moving in an up-down direction relative to the body of the vehicle;

a wheel drive device including a wheel drive unit, a housing of which functions as the carrier;

a brake device including a caliper held by the housing of the wheel drive unit; and

a wheel steering device including i) a steering knuckle as the carrier, ii) a steering actuator including an electric motor as a drive source and disposed on the lower arm, the steering actuator being configured to cause the steering knuckle to be pivoted about a kingpin axis to steer the wheel, and iii) an actuator arm,

wherein a caster angle and a caster offset are both 0 in a state in which the wheel mounting module is mounted on the body of the vehicle,

wherein the wheel steering device is of a steer-by-wire type and is configured to enable the wheel to be steered based on an operation of an operating member by a driver of the vehicle, and

wherein the wheel steering device is used with a reaction-force applying device configured to controllably apply an operation reaction force to the operating member.