POWER STEERING SYSTEM FOR VEHICLE

摘要

PURPOSE: A power steering system of a vehicle is provided to reduce torque of an oil pump by discharging the small amount of operating fluid in not operating a steering wheel, and to steer smoothly by increasing flow rate of operating fluid in operating the steering wheel. CONSTITUTION: A power steering device of a vehicle is composed of a steering gear(22) combined with a steering wheel(20); an oil pump discharging operating fluid to the steering gear; an oil tank(23) storing operating fluid from the oil pump; and a first flow control valve(30) and a second flow control valve(40) installed between the steering gear and the oil pump to discharge operating fluid to the steering gear. The second flow control valve increases the discharge amount of operating fluid according to pressure change in operating the steering wheel. Exhaust pressure is minimized with discharging the small amount of operating fluid in not operating the steering wheel, and steering is performed actively with increasing the flow rate in operating the steering wheel. Driving torque of the oil pump is reduced with adjusting the discharge amount according to pressure.