POWER ASSISTED STEERING SYSTEM, PARTICULARLY FOR MOTOR VEHICLES

摘要

A power assisted steering system, particularly for motor vehicles. of the invention. A power assisted steering system, particularly for motor vehicles, which has a steering gear casing subdivided into two pressure chambers by a hydraulic piston which has a rack portion meshing with a toothed sector of a rocker shaft mounted in said casing. A servo pump is provided for delivering a pressure medium to said casing and a control valve is arranged in said piston transversely and eccentrically thereto for controling the flow of pressure medium to the respective pressure chambers. A recirculatory-ball valve is mounted for limited rotation in the hydraulic piston and co-operates through the recirculatory balls with a steering worm, the ball nut imparting, by means of a driving member secured thereon, to the control valve a control movement which varies in dependence on the steering direction. The control valve is subjected to the action of a centering means which is constituted by a flexural bar spring.