Title:
HELICAL COMPRESSION SPRING AND METHOD OF MANUFACTURING THE SAME
Document Type and Number:
Japanese Patent JP2014206219
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To provide a highly-durable helical compression spring produced while using inexpensive wire rod, by eliminating tensile residual stress caused by coiling, and forming a carbon concentrated layer on a surface of the wire rod to impart an appropriate compressive residual stress distribution to the wire rod after molding.SOLUTION: In a helical compression spring using a steel wire rod including carbon of 0.80 wt.% or less, a carbon concentrated layer exceeding an average concentration of carbon included in the steel wire rod, is formed on a spring inner diameter-side surface layer portion, and a surface carbon concentration and a depth of the carbon concentrated layer are continuously reduced from a spring inner diameter side toward an outer diameter side along the cross-sectional circumference in the arbitrary wire rod cross-section.
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Inventors:
ONO YUICHIRO
SHIRAISHI TORU
SHIRAISHI TORU
Application Number:
JP2013083909A
Publication Date:
October 30, 2014
Filing Date:
April 12, 2013
Export Citation:
Assignee:
NHK SPRING CO LTD
International Classes:
B21F3/06; F16F1/06; B21F35/00; C21D1/06; C21D1/42; C21D7/06; C21D8/00; C21D9/02; C22C38/00; C23C8/22
Domestic Patent References:
| JP2012077367A | 2012-04-19 | |||
| JP2000283201A | 2000-10-13 | |||
| JP5064590B1 | 2012-10-31 | |||
| JP2012117092A | 2012-06-21 | |||
| JP5361098B1 | 2013-12-04 |
Attorney, Agent or Firm:
End 成 Mikio