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.

Date of Patent:
Aug. 22, 1989

Filed:

Dec. 24, 1987
Applicant:
Inventors:

Koichi Fukuo, Saitama, JP;

Mitsuhiro Shibata, Saitama, JP;

Toshiaki Hiro, Saitama, JP;

Masahiko Matsumoto, Saitama, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
F01L / ; F01M / ; F01M / ;
U.S. Cl.
CPC ...
123 9034 ; 123 9016 ; 123 9017 ; 123 9044 ;
Abstract

A hydraulic circuit for a valve operation timing control device for an internal combustion engine which has a low-speed cam having a shape suited for low-speed operation of the engine, a high-speed cam having a shape suited for high-speed operation of the engine, the low- and high-speed cams being integrally formed on a camshaft rotatable in synchronism with a crankshaft, a first rocker arm held in slidable contact with the low-speed cam, a second rocker arm held in slidable contact with the high-speed cam. The first and second rocker arms are adjacent to and in slidable contact with each other and pivotably supported on a rocker shaft for relative angular displacement. There is a first oil feed passage for lubricating the low-speed cam and a second oil feed passage for lubricating the high-speed cam. The first rocker arm has a hydraulic lash adjuster and a relief valve is disposed in the oil passage for supplying oil pressure to said hydraulic lash adjuster for maintaining a predetermined oil pressure on the hydraulic lash adjuster.


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