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:
Apr. 25, 2000
Filed:
Nov. 10, 1997
Applicant:
Inventors:
Akira Harayama, Okaya, JP;
Toshiaki Imai, Okaya, JP;
Assignee:
Teikoku Piston Ring Co., Ltd., Tokyo, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
B32B / ; B23P / ; C25D / ; C23C / ;
U.S. Cl.
CPC ...
428667 ; 428687 ; 205113 ; 205197 ; 205109 ; 205110 ; 277443 ; 277444 ;
Abstract
A piston ring is formed with a nitrided layer over all surfaces and formed with a composite chromium plating film over the nitrided layer in the outer circumferential surface. The composite chromium plating film has a network of cracks formed on the outer surface and interior. Spherical alumina particles are fixed in these cracks. The average size of the spherical alumina particles is 0.7 to 10 .mu.m and the dispersion ratio of the spherical alumina particles is 3 to 15 percent by volume.