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:
May. 12, 1992
Filed:
Sep. 25, 1990
Mizuo Otaki, Kanagawa, JP;
Miyoko Hamao, Kanagawa, JP;
Atsugi Unisia Corporation, Kanagawa, JP;
Abstract
A fluid pump unit has a flow control valve which returns a portion of a working fluid discharged from a pump assembly when rotation speed of a rotor increases to become greater than a predetermined value. The flow control valve includes an essentially cylindrical spool chamber defined in a pump case, and a valve spool movably housed within the spool chamber. The spool chamber has a pair of through openings on the side wall thereof which through openings are selectively open and closed by movement of the spool valve. The pump case is formed with a pair of drain passages which are respectively communicated with the through openings of the spool chamber independently of each other. When rotation speed of a rotor of the pump assembly becomes greater than a predetermined value, the spool valve opens the through openings to return a part of the discharged working fluid to an inlet passage through which working fluid is introduced from a fluid source into the pump assembly.