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:
Mar. 20, 1990
Filed:
Sep. 22, 1988
Makoto Abe, Zushi, JP;
Tetsuyuki Taniguchi, Fujisawa, JP;
Tsuyoshi Kuriki, Yokohama, JP;
Noritoshi Takamura, Kanagawa, JP;
Naoki Terakado, Nagano, JP;
Kaoru Hatayama, Nagano, JP;
Nissan Motor Co., Ltd., Yokohama, JP;
NHK Spring Co., Ltd., Yokohama, JP;
Abstract
A high strength spring is made of steel of which composition consists of 0.6 to 0.7 wt % of C, 1.2 to 1.6 wt % of Si, 0.5 to 0.8 wt % of Mn, 0.5 to 0.8 wt % of Cr, 0.05 to 0.2 wt % in total of one or more than one of V, Mo, Nb and Ta and the balance of Fe and inevitable impurities. The steel is limited in particle size of non-metallic inclusions in such a way that the maximum particle size of the non-metallic inclusions is equal to or smaller than 15 .mu.m. The spring is applied at a portion adjacent the outer surface thereof with a residual compression stress in such a way that the maximum of the residual compression stress ranges from 85 to 110 Kgf/mm.sup.2. The spring is further process so as to have such a surface roughness that is equal to or smaller than 15 .mu.m.