Patent ID: 6035760
Filing Date: 2000-03-14
Classification: B62D,Y10T

Abstract:
A power steering system having a pump and a flow control mechanism 1 for controlling working fluid discharged by the pump and a valve mechanism V for controlling a control flow supplied from the flow control mechanism 1 and operating a power cylinder C, the flow control mechanism 1 maintaining the control flow Q at a minimum flow Q.sub.1 when an assist force is not required and increasing the control flow Q over a range of up to a maximum flow Q.sub.2 available for generating assist force when assist force is required, wherein the valve mechanism V comprises a power cylinder control valve CV for controlling the control flow and distributively supplying it to the power cylinder C and a bypass control valve BV connected in parallel with the cylinder control valve CV and the bypass control valve BV is normally closed but opens and returns a part of the control flow Q to a tank while the control flow Q increases from the minimum flow Q.sub.1 to the maximum flow Q.sub.2 available for generating assist force, the bypass control valve BV again closing once the maximum flow Q.sub.2 is achieved.