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. 07, 1991
Filed:
Jan. 18, 1990
Applicant:
Inventors:
Yasuo Suzuki, Tochigi, JP;
Shunsuke Takeguchi, Tochigi, JP;
Assignee:
Nippon Piston Ring Co., Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
B22F / ;
U.S. Cl.
CPC ...
428552 ; 428469 ; 75241 ; 75243 ; 75237 ; 419 29 ; 74 / ;
Abstract
A camshaft having a tubular steel shaft and a sintered cam piece joined to the shaft. The sintered cam piece has iron tetroxide film at its surface. The camshaft is produced by assembling a powder compact to the steel shaft to provide a camshaft assembly, sintering the assembly to provide an integral assembly, correcting bending to the assembly, annealing the assembly, grinding the cam piece and effecting vaporization treatment to the assembly at a temperature lower than the annealing temperature.