PRODUCTION METHOD FOR FORGED CRANK SHAFT - NIPPON STEEL & SUMITOMO METAL CORP

Title:

PRODUCTION METHOD FOR FORGED CRANK SHAFT

Document Type and Number:

WIPO Patent Application WO/2015/075924

Kind Code:

A1

Abstract:

A production method for a forged crank shaft, including a die-forging step, a burr-removal step, and an excess thickness section-bending step. The die-forging step molds a finished forged material having burrs thereon and having a crankshaft shape molded therein, 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. The burr-removal step removes burrs 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) of the crank arm section (A), by the insertion of a first U-shaped die (10) from the direction of eccentricity onto 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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JP3840954	FORGING DIE STRUCTURE FOR CRANKSHAFT
JPS5016658	PROCESS FOR THE MANUFACTURE OF CRANK-SHAFTS
JP6787937	Crankshaft and its manufacturing method

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)

Application Number:

PCT/JP2014/005813

Publication Date:

May 28, 2015

Filing Date:

November 19, 2014

Export Citation:

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Assignee:

NIPPON STEEL & SUMITOMO METAL CORP (JP)

International Classes:

B21K1/08; B21D3/16; B21J5/02; F16C3/08

Foreign References:

JPH01241348A	1989-09-26
JP2010230036A	2010-10-14
US4015485A	1977-04-05
JPS6127136A	1986-02-06
JP2012007726A	2012-01-12
JP2010230027A	2010-10-14

Other References: