The four-wheel steering system includes a rear-wheel steering system that steers rear wheels of the vehicle in accordance with a steering angle of a steering wheel. When the vehicle speed is lower than a vehicle speed threshold, the rear-wheel steering system steers the rear wheels in an opposite direction to that in which the front wheels are steered. When the vehicle speed is lower than the vehicle speed threshold, the rear-wheel steering system sharply increases the rate of increase in target steered angle of the rear wheels with respect to an increase in steering angle when an absolute value of the steering angle is equal to or larger than an absolute value of an angle threshold. The front-wheel steering system has a motor that is a source of a steering assist force and a first ECU that controls the motor in accordance with the steering state.

The four-wheel steering system includes a rear-wheel steering system that steers rear wheels of the vehicle in accordance with a steering angle of a steering wheel. When the vehicle speed is lower than a vehicle speed threshold, the rear-wheel steering system steers the rear wheels in an opposite direction to that in which the front wheels are steered. When the vehicle speed is lower than the vehicle speed threshold, the rear-wheel steering system sharply increases the rate of increase in target steered angle of the rear wheels with respect to an increase in steering angle when an absolute value of the steering angle is equal to or larger than an absolute value of an angle threshold. The front-wheel steering system has a motor that is a source of a steering assist force and a first ECU that controls the motor in accordance with the steering state.

A wheel suspension includes an axle limb which supports a wheel. The axle limb includes a first steering axle which provides a first steering angle in a specified range for the wheel, and components for connecting the axle limb to a support structure. At least one of the components includes a second steering axle which provides a second steering angle which is different than the first steering angle provided by the first steering axle. The second steering axle is selectively releasable. The components for connecting the axle limb to the support structure form a double transverse link axle which includes an upper traverse link and a lower traverse link. A support tube is arranged at a chassis-side end portion of each of the upper traverse link and the lower traverse link of the double transverse link axle. The support tube is pivotable about the second steering axle.

A steering system includes a drag link having a first support bushing opposite a second support bushing, a first steering hydraulic cylinder operably connected to the drag link, a second steering hydraulic cylinder operably connected to the drag link, a first tie rod operably connected to the drag link, and a second tie rod operably connected to the drag link. Each of the first and second cylinders and first and second tie rods are arranged to apply a corresponding radial force that is distributed between the first and second support bushings. One or more of the first and second steering cylinders and/or the first and second tie rods is positioned relative to the drag link to minimize a net summation of the first and second cylinder radial forces and the first and second tie rod radial forces that are applied to the first and second support bushings.

A wheel suspension includes an axle limb which supports a wheel. The axle limb includes a first steering axle which provides a first steering angle in a specified range for the wheel, and components for connecting the axle limb to a support structure. At least one of the components includes a second steering axle which provides a second steering angle which is different than the first steering angle provided by the first steering axle. The second steering axle is selectively releasable. The components for connecting the axle limb to the support structure form a double transverse link axle which includes an upper traverse link and a lower traverse link. A support tube is arranged at a chassis-side end portion of each of the upper traverse link and the lower traverse link of the double transverse link axle. The support tube is pivotable about the second steering axle.

A wheel suspension includes an axle limb which supports a wheel. The axle limb includes a first steering axle which provides a first steering angle in a specified range for the wheel, and components for connecting the axle limb to a support structure. At least one of the components includes a second steering axle which is selectively releasable in order to provide a steering angle which is different than the first steering axle. The components for connecting the axle limb to the support structure form a McPherson suspension.

A steering system includes a drag link having a first support bushing opposite a second support bushing, a first steering hydraulic cylinder operably connected to the drag link, a second steering hydraulic cylinder operably connected to the drag link, a first tie rod operably connected to the drag link, and a second tie rod operably connected to the drag link. Each of the first and second cylinders and first and second tie rods are arranged to apply a corresponding radial force that is distributed between the first and second support bushings. One or more of the first and second steering cylinders and/or the first and second tie rods is positioned relative to the drag link to minimize a net summation of the first and second cylinder radial forces and the first and second tie rod radial forces that are applied to the first and second support bushings.

The four-wheel steering system includes a rear-wheel steering system that steers rear wheels of the vehicle in accordance with a steering angle of a steering wheel. When the vehicle speed is lower than a vehicle speed threshold, the rear-wheel steering system steers the rear wheels in an opposite direction to that in which the front wheels are steered. When the vehicle speed is lower than the vehicle speed threshold, the rear-wheel steering system sharply increases the rate of increase in target steered angle of the rear wheels with respect to an increase in steering angle when an absolute value of the steering angle is equal to or larger than an absolute value of an angle threshold. The front-wheel steering system has a motor that is a source of a steering assist force and a first ECU that controls the motor in accordance with the steering state.

The four-wheel steering system includes a rear-wheel steering system that steers rear wheels of the vehicle in accordance with a steering angle of a steering wheel. When the vehicle speed is lower than a vehicle speed threshold, the rear-wheel steering system steers the rear wheels in an opposite direction to that in which the front wheels are steered. When the vehicle speed is lower than the vehicle speed threshold, the rear-wheel steering system sharply increases the rate of increase in target steered angle of the rear wheels with respect to an increase in steering angle when an absolute value of the steering angle is equal to or larger than an absolute value of an angle threshold. The front-wheel steering system has a motor that is a source of a steering assist force and a first ECU that controls the motor in accordance with the steering state.

A steering system for a vehicle includes a drive motor having a motor shaft. The steering system also includes a first gear reduction stage for receiving a first rotational input from the motor shaft and providing a first rotational output. The steering system further includes a second gear reduction stage for receiving the first rotational output from the first gear reduction stage and providing a second rotational output. The second gear reduction stage may include at least one of a strain wave gearing, a worm drive, and a planetary gearing. The steering system includes an output shaft for receiving the second rotational output from the second gear reduction stage.