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:
Jul. 29, 1997
Filed:
Nov. 12, 1996
Ali Devrim Can, Simpsonville, SC (US);
James Leroy Davison, Freeland, MI (US);
General Motors Corporation, Detroit, MI (US);
Abstract
A hydraulic pump having a flow control valve for recirculating a fraction of the discharge of a rotating group of the pump and an externally adjustable pressure relief valve. The flow control valve includes a cylindrical bore in a housing of the pump, a discharge passage intersecting the bore, a recirculation passage intersecting the bore, and a valve spool slideable in the bore. A valve body on the housing closes an open end of the cylindrical bore and cooperates with the valve spool in defining a spring chamber connected to the discharge passage. A spring in the spring chamber biases the valve spool to a position corresponding to zero recirculation. The relief valve includes a stepped bore in the valve body, a valve seat in the stepped bore, a valve element, a spring biasing the valve element against the valve seat, and a spherical metal spring seat interference fitted in the stepped bore. The spherical spring seat is plunged into the stepped bore while the pump is operating to compress the relief valve spring until a reaction force of the relief valve spring on the relief valve element induces a preselected pump relief pressure.