VEHICLE HYDRAULIC POWER STEERING SYSTEM WITH MEANS FOR CONTROLLING THE OPERATION OF A POWER STEERING PUMP

摘要

In a vehicle hydraulic power steering system, the operation of a pump (9) for supplying a pressurized working fluid to a power steering unit (6) is controlled in accordance with an output signal of a control means (20) which is responsive to detected values of a speed of the rotation of a steering wheel and a pressure of the working fluid supplied to said power steering unit (6). The operation of the pump is initiated when the steering wheel (1) is turned at a speed of the rotation higher than a predetermined value and it is ceased when the pressure of the working fluid is reduced below a predetermined value due to the termination of a power assist operation of the power steering system.