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. 14, 1996
Filed:
May. 24, 1994
Tetsuo Tsukamoto, Hadano, JP;
Kiyoshi Ohkawachi, Hadano, JP;
Shinji Fushimi, Yokosuka, JP;
Shunzo Umegaki, Yokohama, JP;
Takashi Matsumoto, Yokohama, JP;
Nissan Motor Co., Ltd., Yokohama, JP;
Nittan Valve Co., Ltd., Tokyo, JP;
Abstract
A hardened surface layer is formed in the region of inner and outer surfaces of a hollow material having a central through hole, then the hollow material is hot-forged into a hollow gear-like forged body by a forging die having a first die element with a piercing punch entering into the central through hole of the hollow material from one side thereof and having a second die element with a piercing punch entering into the central through hole of the hollow material from another side thereof. The forging die forms teeth of the gear on the outer side of the hollow material while producing an annular flash in the central through hole of the hollow material between the piercing punches. A distance between the piercing punches in a closed condition of the forging die defines a thickness of the annular flash which is 0.3 mm or more and no greater than 1.3 times (130%) of a depth of the hardened surface layer. After that, the annular flash is removed from the forged body, and thermal refining is implemented to the forged body by quenching and tempering.