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. 04, 1999
Filed:
Aug. 29, 1997
Yoshikatsu Nakamura, Shimotsuga-gun, JP;
Tetsuo Masuyama, Shimotsuga-gun, JP;
Nippon Piston Ring Co., Ltd., Tokyo, JP;
Abstract
In an aspect of the present invention, a synchronizer ring, made of Fe-based sintered alloy, having an internal circumferential surface 101, is provided, the internal circumferential surface 101 being adapted to detachably engage in synchronized sliding with a rotating counterpart member thereof. At least the internal circumferential surface 101 is applied with aqueous vapor treatment to form iron oxide film thereon. In another aspect of the present invention, the iron oxide film has surface roughness not less than 20 .mu.mRz but not more than 55 .mu.mRz. In a further aspect of the present invention, the iron oxide film has a surface roughness not less than 25 .mu.mRz but not more than 35 .mu.mRz. In another aspect of the present invention, the iron oxide film has a thickness not less than 0.05 .mu.m but not more than 5 .mu.m. In a further aspect of the present invention, the major component of the iron oxide film is Fe.sub.3 O.sub.4. In a still further aspect of the present invention, at least the internal circumferential surface is applied with blasting treatment in addition to, and in combination with, the aqueous vapor treatment to form iron oxide film thereon.