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:
Feb. 17, 1998
Filed:
Dec. 17, 1996
Applicant:
Inventors:
Assignee:
Teikoku Piston Ring Co., Ltd., Tokyo, JP;
Primary Examiner:
Int. Cl.
CPC ...
F16J / ;
U.S. Cl.
CPC ...
277139 ; 2772 / ;
Abstract
A combined oil ring is comprised of paired upper and lower side rails, and a spacer expander. The side rails are made of martensitic stainless steel and are subjected to gas nitriding. The spacer expander is made of austenitic stainless steel, with a substantially U-shaped cross section, and has an under layer formed by soft nitriding, and has a Cr.sub.2 N film. The Cr.sub.2 N film has a hardness of HV1300 to HV2000 and a thickness of 3 .mu.m to 30 .mu.m. The Cr.sub.2 N film is formed by ion plating on the soft-nitrided layer of the outer circumferential surface.