HELICAL COMPRESSION SPRING AND METHOD FOR PRODUCING SAME

Title:

HELICAL COMPRESSION SPRING AND METHOD FOR PRODUCING SAME

Document Type and Number:

WIPO Patent Application WO/2018/190331

Kind Code:

A1

Abstract:

Provided is a helical compression spring with high durability and high settling resistance obtained by forming a C-enriched layer having a very thin and even thickness on a wire surface, so as to provide a residual compressive stress distribution suitable for a molded wire. The helical compression spring is made of a steel wire that comprises, by wt%, 0.5%-0.7% of C, 1.2%-3.0% of Si, 0.3%-1.2% of Mn, 0.5%-1.9% of Cr, and 0.05%-0.5% of V, optionally at least one or two of 1.5% or less of Ni, 1.5% or less of Mo, and 0.5% or less of W, and the balance iron and inevitable impurities. The helical compression spring has, on the surface layer thereof, a C-enriched layer having a carbon concentration that exceeds the average concentration of C contained in the steel wire, and the thickness of the C-enriched layer is set to be within the range of 0.01-0.05 mm over the entire circumference of the steel wire.

Inventors:

AKANUMA TOSHIYUKI (JP)
SHIRAISHI TOHRU (JP)
IWAGAKI YOHEI (JP)
TAKAHASHI KEITA (JP)
HIRAI SHUN (JP)

Application Number:

PCT/JP2018/015034

Publication Date:

October 18, 2018

Filing Date:

April 10, 2018

Export Citation:

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Assignee:

NHK SPRING CO LTD (JP)

International Classes:

C22C38/00; C21D1/06; C21D7/06; C21D9/02; C22C38/46; F16F1/06; C22C38/54

Domestic Patent References:

WO2014042066A1

2014-03-20

Foreign References:

JP2014206219A	2014-10-30
JP2009052144A	2009-03-12
JPH10305342A	1998-11-17
JP2004323912A	2004-11-18
JPS595901B2	1984-02-07
JP2014055343A	2014-03-27
JP2009226523A	2009-10-08

Other References: