Power steering system for vehicles

摘要

An improved power steering system for vehicles is utilized in association with a variable discharge pump for supplying pressure fluid to one of both cylinder chambers divided by a piston of a power cylinder, selectively. The power steering system includes a variable throttle provided in a fluid supplying passage between the pump and the cylinder chamber. Upon rotation of a steering shaft, an adjusting member adjusts a cross sectional area of the variable throttle in accordance with the variable steering torque. The power steering system also includes a discharge quantity controller for controlling a discharge quantity of the pressure fluid of the pump so that a pressure differential between up and downstreams of the variable throttle is constant. The discharge quantity of the pressure fluid of the pump is changed to be suitable to the any variable steering torque.