Electric power steering system for a motor vehicle

Abstract

In an electric power steering system, a d.c. motor is drivingly connected to a steering shaft with a steering for generating an assisting power to rotate the steering shaft. Independently of an alternator for charging a battery, a d.c. generator driven by a vehicle engine is dedicated for supplying an electric power to the d.c. motor. A control circuit is responsive to a signal representing a manual torque applied to the steering and reads out one of objective values from a memory. The control circuit is further responsive to a fed-back signal indicative of a load applied to the d.c. motor and controls electric current flowing across a field coil of the d.c. generator in such a manner that the difference between the read-out objective value and the fed-back signal becomes zero.