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. 20, 2010
Filed:
Mar. 24, 2004
Tomohiro Nakano, Nagoya, JP;
Takayuki Sakakibara, Nagoya, JP;
Masami Wakita, Nagoya, JP;
Chuo Hatsujo Kabushiki Kaisha, Nagoya-shi, JP;
Abstract
The present invention intends to provide a method for manufacturing a high-strength spring, which is capable of generating a higher level of compressive residual stress than that given by conventional methods. This object is achieved as follows: After the final heating process, such as the tempering (in the case of a heat-treated spring) or removing-strain annealing (in the case of a cold-formed spring), a shot peening process is performed on the spring while the surface temperature of the spring is within the range from 265 to 340° C. (preferably from 300 to 340° C.). Subsequently, the spring is rapidly cooled. Preferably, a prestressing process is performed before the shot peening process, or after the shot peening process and before the rapid cooling process. The rapid cooling process may be either a water-cooling process or an oil-cooling process. A forced-air cooling process may be used if the wire diameter of the spring is small.