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. 30, 2002
Filed:
Apr. 02, 2001
John P. Miller, Northville, MI (US);
General Motors Corporation, Detroit, MI (US);
Abstract
A positive displacement rotary pump including a housing having an internal chamber and inlet and discharge ports, a sealing land on the housing between a downstream end of the inlet port and an upstream end of the discharge port, and a rotating group in the internal chamber defining a plurality of pump chambers. The pump chambers traverse in succession and at regular intervals the inlet port and the sealing land and the discharge port. The housing has a stationary pre-charging passage which communicates with the discharge port and overlaps the sealing land. The rotating group includes a plurality of rotating pre-charging passages which communicate with respective ones of the pump chambers. As each rotating pre-charging passage attains overlap with the stationary pre-charging passage, the low pressure of the fluid trapped in the corresponding pump chamber sealed closed in the sealing land increases rapidly and induces a pulse in the fluid in the discharge port and in the fluid system connected to the discharge port. The angular separation between the rotating pre-charging passages is randomly unequal so that the intervals between pulses are irregular. The irregular intervals between the pulses suppresses tonal pump noise.