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:
Sep. 27, 2016
Filed:
Oct. 17, 2014
Hitachi Automotive Systems, Ltd., Hitachinaka-shi, Ibaraki, JP;
Yasushi Watanabe, Kanagawa, JP;
Hideaki Ohnishi, Atsugi, JP;
HITACHI AUTOMOTIVE SYSTEMS, LTD., Hitachinaka-Shi, JP;
Abstract
An oil pump includes a relief valve. The relief valve adjusts a pump discharge pressure depending on a differential pressure between the pump discharge pressure and a back pressure chamber pressure. An electromagnetic switching valve includes a movable member moved electromagnetically. The movable member brings a ball valve element selectively into a state pressed onto a valve seat portion, to selectively close and open an oil passage. The electromagnetic switching valve selectively supplies the pump discharge pressure to a back pressure chamber of the relief valve and drains the back pressure chamber of the relief valve by selectively opening and closing the oil passage. A pilot valve is disposed downstream of the electromagnetic switching valve, and operates upon receipt of the pump discharge pressure or the back pressure chamber pressure, and controls an oil pressure supplied to the back pressure chamber of the relief valve.