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:
Aug. 22, 2000
Filed:
Apr. 27, 1998
John Gardner Fischer, Goodrich, MI (US);
Giulio Angel Ricci-Ottati, Burton, MI (US);
General Motors Corporation, Detroit, MI (US);
Abstract
A gerotor pump including a ring gear and a pinion gear supported on a pump housing for rotation about parallel, laterally separated centerlines. A plurality of pump chambers defined by the teeth of the ring and pinion gears expand in an inlet half of a crescent-shaped cavity between the ring and pinion gears and collapse in a discharge half. An inlet port in a first side wall of the pump housing faces the inlet half of the crescent-shaped cavity. A primary discharge port in an opposite second side wall of the pump housing faces the discharge half of the crescent-shaped cavity and is timed relative to the inlet port for pumping low bulk modulus fluid. A shallow groove in the first end wall of the housing defines a secondary discharge port timed relative to the inlet port for pumping high bulk modulus fluid. In the timing interval between the secondary and the primary discharge ports, i.e. when the pump chambers overlap only the secondary discharge port, the shallow groove defines a restricted passage which releases high bulk modulus fluid to prevent pressure spikes while maintaining sufficient back pressure to collapse entrained vapor bubbles in low bulk modulus fluid.