Abstract: Controller is designed to control operation of a rear-wheel steering apparatus typically provided in a four-wheel steering vehicle, and is based on electronic circuitry. In the electronic circuitry, a target-steering-angle setting section sets a target steering angle of the rear wheels. Actual-steering-angle measurement section measures an actual steering angle of the rear wheels. On the basis of the target steering angle and actual steering angle, a steering-angle adjustment section generates a motor drive signal to control the rotation of the motor in such a manner that a difference or offset between the target steering angle and the actual steering angle becomes zero. On condition that the motor is in a predetermined driving state, a motor-deceleration-amount calculation section is activated to calculate an actual rotating speed of the motor on the basis of the actual steering angle of the rear wheels and compares the calculated actual rotating speed of the motor with a prestored reference rotation speed.

Abstract: A rear wheel steering apparatus is disclosed which comprises a pair of threaded members which are threaded in a direction opposite to one another, a pair of slide members engaging with the threaded members, respectively, and movable toward and away from one another due to reverse thread action, a steering shaft for steering a pair of rear wheels, and an electric motor for rotating the threaded members to move the steering shaft coupled to one of the slide members toward one of the rear wheels for thereby steering the rear wheels.

Abstract: A rear wheel steering device steers rear wheels of a vehicle by using two electric motors. When the two electric motors are in normal condition, both electric motors are driven to steer the rear wheels. When one electric motor is in an abnormal state while the other electric motor is in a normal state and when a vehicle speed exceeds a given speed, the steering device controls steering of the rear wheels by using only the other electric motor being in normal condition. Since the employed electric motors are small-sized and inexpensive, the rear wheel steering device can be downsized and provided at a relatively low cost.

Abstract: A rear wheel steering apparatus is disclosed which comprises a pair of threaded members which are threaded in a direction opposite to one another, a pair of slide members engaging with the threaded members, respectively, and movable toward and away from one another due to reverse thread action, a steering shaft for steering a pair of rear wheels, and an electric motor for rotating the threaded members to move the steering shaft coupled to one of the slide members toward one of the rear wheels for thereby steering the rear wheels.

Abstract: Provided is a rear wheel steering device which includes a rotary shaft having a pair of threaded sections of mutually opposite senses, and a pair of slide members supported in a rotationally fast manner, and having threaded sections which engage the corresponding threaded sections of the rotary shaft so as to be moveable in mutually opposite axial directions as the rotary shaft is turned in either direction, and a pair of clutch units each interposed between a corresponding one of the slide members and the slide shaft for selectively coupling them in an axially fast manner. Thus, the steering direction can be determined by selectively engaging either one of the clutch units, and the magnitude of the steering angle can be determined by turning the rotary shaft with an electric motor in either direction.