Title:
PRODUCTION METHOD FOR FORGED CRANK SHAFT
Document Type and Number:
WIPO Patent Application WO/2015/075934
Kind Code:
A1
Abstract:
A production method for forged crank shafts that includes a die-forging step, a burr-removal step, and an excess thickness section-bending step. In the die-forging step, a finished forged material having burrs thereon and having a crankshaft shape molded therein is molded, said crank shaft shape having excess thickness sections (Aaa, Aba) in the outer perimeter of both side sections (Aa, Ab) in the vicinity of a pin section (P) of a crank arm section (A), said excess thickness sections (Aaa, Aba) protruding from said outer perimeter. In the burr-removal step, burrs are removed from the finished forged material molded in the die-forging step. In the excess thickness section-bending step, the excess thickness sections (Aaa, Aba) of the crank arm section are bent towards the surface on a journal section (J) side of the crank arm section (A), by pressing downwards, using a pair of first dies (10A, 10B), on to the crank shaft having had the burrs removed therefrom in the burr-removal step. As a result, a forged crank shaft that is lighter and has rigidity ensured can be easily obtained.
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Inventors:
TAMURA KENJI (JP)
OKUBO JUNICHI (JP)
ISHIHARA KOICHIRO (JP)
YOSHINO KEN (JP)
YABUNO KUNIHIRO (JP)
KUROKAWA HIROYUKI (JP)
YAMASHITA TOMOHISA (JP)
TAKAMOTO SHO (JP)
OKUBO JUNICHI (JP)
ISHIHARA KOICHIRO (JP)
YOSHINO KEN (JP)
YABUNO KUNIHIRO (JP)
KUROKAWA HIROYUKI (JP)
YAMASHITA TOMOHISA (JP)
TAKAMOTO SHO (JP)
Application Number:
PCT/JP2014/005835
Publication Date:
May 28, 2015
Filing Date:
November 20, 2014
Export Citation:
Assignee:
NIPPON STEEL & SUMITOMO METAL CORP (JP)
International Classes:
B21K1/08; B21D3/16; B21J5/02; F16C3/08
Foreign References:
| JPH0411913U | 1992-01-30 | |||
| JPS5137056A | 1976-03-29 | |||
| JPS5348046A | 1978-05-01 | |||
| US3534579A | 1970-10-20 | |||
| JP2010230036A | 2010-10-14 | |||
| US4015485A | 1977-04-05 | |||
| JP2012007726A | 2012-01-12 | |||
| JP2010230027A | 2010-10-14 |
Other References:
See also references of EP 3072607A4
Attorney, Agent or Firm:
ASCEND IP LAW FIRM (JP)
アセンド patent business corporation (JP)
アセンド patent business corporation (JP)
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