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. 07, 2013
Filed:
Aug. 21, 2009
Hirokazu Ooba, Iwata, JP;
Kazuhiko Yoshida, Iwata, JP;
Keisuke Sone, Iwata, JP;
NTN Corporation, Osaka, JP;
Abstract
A power transmission shaft includes a torque-transmission teeth portion formed on an outer peripheral surface on an end portion side, and a smooth portion formed on the outer peripheral surface adjacent to the torque-transmission teeth portion so as to have a stepwise reduced diameter. A ratio of a minimum diameter of the smooth portion to a minimum diameter of the torque-transmission teeth portion is set to 0.9 or more and 1.02 or less. Further, the torque-transmission teeth portion and the smooth portion undergo heat treatment so as to form a heat-treated hardened layer. The heat-treated hardened layer is formed to increase in depth from a side of the torque transmission teeth portion to a side of the smooth portion. At least a minimum diameter portion of the smooth portion undergoes full hardening.