The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 16, 1993
Filed:
Jun. 25, 1991
Richard H Smith, Birmingham, MI (US);
General Motors Corporation, Detroit, MI (US);
Abstract
An automotive power steering gear having a four-way, open-center valve defining inlet branch passages between an inlet port of the steering gear and opposite working chambers of a steering assist fluid motor and further defining discharge branch passages between the opposite fluid motor working chambers and a discharge port of the steering gear. Lands and grooves on a spool and a sleeve of the valve define variable orifices in the inlet and discharge branch passages. The steering gear further includes bypass passages around each of the variable orifices in the inlet branch passages and check valves in the bypass passages which open the passages only when the pressure in the corresponding one of the fluid motor working chambers exceeds the pressure at the inlet port. When one or the other of the check valves is open, fluid recirculates from one of the fluid motor working chambers to the other.