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:
Dec. 26, 1989

Filed:

Nov. 18, 1988
Applicant:
Inventors:

Toru Yagi, Tokyo, JP;

Yoshihiro Fujiyoshi, Kanagawa, JP;

Takatoshi Aoki, Tokyo, JP;

Yasuhiro Urata, Saitama, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
F01L / ;
U.S. Cl.
CPC ...
123 9012 ; 123 9055 ; 123 9057 ;
Abstract

A valve operating device for an internal combustion engine that includes a valve piston having one end facing into a damper chamber and the other end operatively coupled to an intake or exhaust valve which is spring-biased in a closing direction. A cam piston has one end operatively coupled to a cam drivable by a crankshaft and the other end disposed in a working oil chamber. A restriction mechanism uniformly restricts oil flow during final valve closing operation of the intake or exhaust valve until the valve is fully closed. The working oil chamber and damper chamber are held in communication with each other through the restriction mechanism. A bypass passage interconnects the damper chamber and the working oil chamber in bypassing relation to the restriction mechanism. A variable restriction mechanism is provided in the bypass passage capable of varying the area for oil flow according to valve closing characteristics required by the viscosity of working oil and operating conditions of the engine.


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