Patent ID: 7124855

Claim:
A flow controlling apparatus for a power steering system, comprising: a pump; a hydraulic device receiving discharged oil from said pump to assist a steering wheel by hydraulic power; a variable throttle mechanism installed in said pump to change a flow rate of said discharged oil from said pump to said hydraulic device; a linear solenoid mechanism controlling said variable throttle mechanism according to a predetermined energizing current; a spool feeding back excess discharged oil to a bypass passage of said pump in accordance with a differential pressure between upstream and downstream sides of said variable throttle mechanism when said excess fluid exceeds a predetermined value; and control means for controlling said energizing current to cause said variable throttle mechanism to transition from providing a standby flow rate of said discharged oil to providing an assist flow rate of said discharged oil in accordance with a steering angular velocity of said steering wheel when it is determined that said steering wheel is being turned, wherein said control means controls said energizing current to more rapidly increase said transition from a standby flow rate to an assist flow rate when said steering angular velocity is large, and to more slowly increase said transition from a standby flow rate to an assist flow rate when said steering angular velocity is small, and wherein said control means sets a time constant of an increase of the energizing current to have a small value so that said transition is rapid when said steering angular velocity is large, and sets the time constant to have a large value so that said transition is slow when said steering angular velocity is small.