Patent ID: 6931981

Claim:
A hydraulic power-assisted steering system comprising: a pump containing hydraulic fluid; a rack and pinion housing operatively connected to said pump via a conduit line; a hydraulic fluid control device operatively disposed between said pump and said rack and pinion housing, said hydraulic fluid control device having a passageway formed therethrough to allow hydraulic fluid to flow from said pump to said rack and pinion housing; an electromagnet operatively coupled to said fluid control device; and an electronic control unit adapted to receive at least one input signal from at least one input source so as to generate an output signal to said hydraulic fluid control device so as to selectively control the flow of hydraulic fluid from said pump to said rack and pinion housing; wherein said fluid control device is formed from a magnetostrictive alloy material which is capable of changing the size of said passageway in said hydraulic fluid control device in response to an applied magnetic field, whereby said electronic control unit is operative to selectively control the physical shape or size of said passageway of said hydraulic fluid control device thereby selectively controlling the flow of hydraulic fluid from said pump to said rack and pinion housing.