Rear wheel steering system for motor vehicle

Claim 1

A steering control system for a motor vehicle, including an antiskid braking system which controls a braking force in a brake device for a respective wheel in accordance with a deceleration condition of the respective wheel so as to prevent wheel locking in a braking operation, the system comprising: a rear steering control system for establishing a ratio of a steering amount of the rear wheels to a steering amount of the front wheels as a predetermined steering ratio characteristic; means for inputting signals representing an operation condition of the antiskid braking system and a control condition of the brake device for the respective wheel conducted by the antiskid braking system to the rear steering control system; means for amending the predetermined steering ratio characteristic to a second steering ratio characteristic in accordance with the control condition of the brake device for the respective wheel when the antiskid braking system is in operation; and means for sensing respective lock conditions of respective front and rear wheels; wherein said means for amending the predetermined steering ratio characteristic amends the predetermined steering ratio characteristic to a third steering ratio characteristic which is positioned in a positive steering direction area relative to the predetermined steering ratio characteristic when said respective lock conditions of the respective front and rear wheels are substantially equal to each other, (b) the predetermined steering ratio characteristic to a fourth steering ratio characteristic which is positioned in said positive steering direction area relative to the predetermined steering ratio characteristic and in a negative steering direction area relative to the third steering ratio characteristic when the front wheels are locked earlier than the rear wheels, and (c) the predetermined steering ratio characteristic to a fifth steering ratio characteristic which is positioned in said positive steering direction area further from the third steering ratio characteristic when the rear wheels are locked earlier than the front wheels.