Gm Global Technolgoy Operations, Inc.

Michael T Masica

Albert C Wong

Paul O Wendler

John F Yonker

A demand responsive flow regulator valve for use with a power steering pump and steering mechanism has a valve spool slidably disposed in a housing and responsive to a pressure differential across an orifice for the purpose of bypassing excess pump flow. The flow control orifice establishes pressure signals proportional to pump flow to the steering mechanism. The pressure signals are operative on the valve spool to control the bypassing of excess pump flow. A spring loaded metering rod disposed in the flow control orifice increases the effective area of the orifice when pressure demand at the steering mechanism increases thereby increasing the fluid flow to the steering mechanism while simultaneously decreasing the bypass flow.

Demand responsive flow regulator valve

A hydraulic power steering system has a vane type pump which is operable to supply fluid to a steering gear at a volumetric rate determined in part by the system pressure or system demand. The pump flow is partially bypassed through a valve member disposed in the cam ring at a position adjacent the pumping chambers. The valve is spring loaded radially inward to permit the bypass flow at low system pressure levels. Increasing system pressure levels bias the valve member radially outward thereby reducing bypass flow while simultaneously increasing pump discharge flow. At a predetermined pressure level, the valve member will reach a secondary opening position to bypass fluid flow and thereby limit the maximum system pressure.

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Saginaw, MI, United States of America

Michael T Masica