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:
Jan. 24, 2012
Filed:
Jul. 21, 2005
Katsuhiro Sakurai, Shizuoka, JP;
Toru Nakagawa, Shizuoka, JP;
Masamichi Shinbo, Shizuoka, JP;
Masami Yamaguchi, Shizuoka, JP;
Tsuneaki Hiraoka, Shizuoka, JP;
Katsuhiro Sakurai, Shizuoka, JP;
Toru Nakagawa, Shizuoka, JP;
Masamichi Shinbo, Shizuoka, JP;
Masami Yamaguchi, Shizuoka, JP;
Tsuneaki Hiraoka, Shizuoka, JP;
NTN Corporation, Osaka, JP;
Abstract
A hollow shaft material is provided with, on an outer peripheral surface side thereof, for example, a movable induction heating coil wrapped therearound. While a high-frequency current with a predetermined frequency is caused to flow through the induction heating coil, the induction heating coil is axially moved to perform induction hardening of the hollow shaft material from the outer peripheral surface side. At this moment, the frequency of the high-frequency current caused to flow through the induction heating coil is set relatively low as to the small-diameter portions, which have a relatively small thickness, and the frequency of the high-frequency current caused to flow through the induction heating coil is set relatively high as to the large-diameter portion, which has a relatively small thickness.