METHOD FOR MANUFACTURING COIL SPRING

Title:

METHOD FOR MANUFACTURING COIL SPRING

Document Type and Number:

WIPO Patent Application WO/2010/146907

Kind Code:

A1

Abstract:

A spring wire (20) is subjected to a first shot-peening step (S6) and a second shot-peening step (S7). At the first shot-peening step (S6), a first shot is projected at the spring wire (20) at a first projecting speed. The high kinetic energy of the first shot produces a compression residual stress from the surface to a deep location of the spring wire (20). At the second shot-peening step (S7), the second shot is projected at a second projecting speed slower than the projecting speed of the first shot. The kinetic energy of the second shot is lower than the kinetic energy of the first shot. The low kinetic energy of the second shot increases the compression residual stress of a region near the surface of the spring wire (20).

Inventors:

TANGE AKIRA (JP)
OKADA HIDEKI (JP)
UESUGI MOTOI (JP)
HISANO YOSUKE (JP)

Application Number:

PCT/JP2010/054689

Publication Date:

December 23, 2010

Filing Date:

March 18, 2010

Export Citation:

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Assignee:

NHK SPRING CO LTD (JP)
TANGE AKIRA (JP)
OKADA HIDEKI (JP)
UESUGI MOTOI (JP)
HISANO YOSUKE (JP)

International Classes:

B24C1/10; F16F1/02; F16F1/06; B21F35/00

Foreign References:

JP2005003074A	2005-01-06
JP2005002365A	2005-01-06
JP2003117830A	2003-04-23
JP2000345238A	2000-12-12
JP2008106365A	2008-05-08

Other References: