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:
Mar. 05, 2002
Filed:
Oct. 29, 1999
Shoji Morita, Kanagawa, JP;
Hideaki Ohnishi, Kanagawa, JP;
Unisia Jecs Corporation, Atsugi, JP;
Abstract
A pressure relief valve for an oil pump of an automotive internal combustion engine. The pressure relief valve comprises a wall defining thereinside a valve accommodating bore. The wall is formed with a plurality of pressure relief holes including first and second pressure relief holes through which oil in the valve accommodating bore is releasable to an outside of the valve accommodating bore. A valve body is provided to be slidably movable in the valve accommodating bore and along the wall under balance between oil pressure acting on the valve body in a first direction and biasing force of a spring acting on the valve body in a second direction opposite to the first direction. In this arrangement, the second pressure relief hole is opened after the first pressure relief hole is opened to have a maximum cross-sectional opening area in a process of movement of the valve body in the first direction along the axis of the valve accommodating bore.