Patent ID: 7065436

Claim:
A variable ratio steering system of a vehicle comprising: a variable steering ratio mechanism that varies a steering ratio of a steering angle of a manually-operated steering mechanism to a road wheel steer angle at a steered road wheel; a vehicle speed sensor that detects a vehicle speed; a steering angle sensor that detects the steering angle; a steering ratio control unit configured to be electronically connected to the vehicle speed sensor, the steering angle sensor and the variable steering ratio mechanism, for controlling the variable steering ratio mechanism responsively to the vehicle speed and the steering angle; and wherein the steering ratio control unit keeps the steering ratio constant irrespective of the vehicle speed under a condition where the steering angle is less than or equal to a predetermined angle substantially corresponding to a neutral position of the manually-operated steering mechanism, for stabilizing a steering-wheel angular position, required to maintain a running state of the vehicle at straight ahead, at the neutral position, in presence of offsetting of a steering angle versus road wheel steer angle characteristic from a predetermined characteristic.