Honda Giken Kogyo Kabushiki Kaisha

Honda Motor Co., Ltd.

Kunio Shirakawa

Hiroshi Furumi

Yoshinobu Mukai

Osamu Tsurumiya

Hisao Asaumi

Shunsuke Watanabe

Masaaki Kawano

Kazuhisa Watanabe

Hirokazu Kitazawa

Yoshio Kakizaki

Kiyohide Nagase

Takafumi Ozaki

Kazuhiko Satou

Tatsuya Amano

Paul Baron

A vehicle steering apparatus utilizing SBW capable of downsizing an expensive turning-power motor, in which a steering mechanismprovided with a steering wheelmaneuvered by a driver is mechanically separated from a turning mechanismfor turning road wheels. A turning-power motorof the turning mechanismturns the road wheelsbased on a turning angle-steering angle ratio determined by a control portionof a controllerin accordance with a vehicle speed of the vehicle. The turning angle-steering angle ratio increases with increasing vehicle speed until the vehicle speed reaches a predetermined value from zero; while when the vehicle speed is higher than the predetermined value, the turning angle-steering angle ratio decreases with increasing vehicle speed.

Vehicle steering apparatus

In a steering handle grasped and rotated by both hands of a driver, an axis of a steering shaft included in the steering handle is inclined so as to be higher in level in a forward direction of a vehicle body, and a left grip grasped by a left hand and a right grip grasped by a right hand are rotatable in opposite directions about an axis perpendicular to the axis of the steering shaft. Accordingly, an upper half of the driver's body sitting on a seat and leaning backwards and a plane of rotation of the steering handle are substantially parallel to each other, thereby ensuring that the driver can rotate the steering handle without stretching and withdrawing his or her arms. Moreover, when the steering handle is rotated, the driver's wrists can be prevented from being twisted unnaturally, leading to an easy steering operation.

Steering handle and steering system

A worm gear and an irreversible clutch mechanism adapted to permit the transmission of a driving force from an actuator toward rear wheels and to inhibit the transmission of the driving force in a reverse direction, are disposed at upstream and downstream locations in a power-transmitting path for transmitting the driving force from the actuator to the rear wheels, respectively. The driving force transmitted in the reverse direction from the rear wheels toward the actuator is blocked by both the irreversible clutch mechanism and the worm gear. Therefore, the steering angle of the rear wheels can be reliably prevented from changing from a desired angle. Further, even when one of the irreversible clutch mechanism and the worm gear is broken, the function of inhibiting the reverse transmission of the driving force can be maintained. Especially, because the irreversible clutch mechanism having a chattering smaller as compared with the worm gear is disposed in the downstream location, the rigidity of the rear wheels against a load from a road surface can be effectively enhanced.

Rear-wheel steering device for vehicle

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.

Rear wheel steering device

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. The motor-deceleration-amount calculation section operates to calculate a motor-rotation deceleration amount when the compared result indicates that the calculated actual rotating speed is higher than the reference rotation speed.

Control unit for rear-wheel steering apparatus

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. In the rear wheel steering apparatus which further comprises control means and for controlling the electric motor, and motor drive means including a bridge circuit composed of four switching elements for enabling forward or reverse rotations of the electric motor on the basis of a signal delivered from the control means, the improvement comprises a trouble compensation circuit constituted independently of the control means and for turning on the switching elements for a given time interval, during a failure taking place in the control means and so as to drive the electric motor in a direction to cause the pair of slide members to move toward each other.

Rear wheel steering apparatus

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. In particular, when it is desired to bring the steering device to the neutral position, it can be achieved simply by turning the electric motor in a prescribed direction without regard to the current state of the steering device.

Growing community of inventors

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