Title:
COMPRESSION COIL SPRING AND METHOD FOR PRODUCING SAME
Document Type and Number:
WIPO Patent Application WO/2023/120475
Kind Code:
A1
Abstract:
The present invention addresses the problem of providing a compression coil spring in which an appropriate amount of residual austenite is made present near the surface thereof by optimizing tempering conditions, and cracking is suppressed by the residual austenite. The present invention has a composition including, in terms of mass%, 0.45-0.8% C, 0.15-3.0% Si, and 0.3-1.0% Mn, the remainder comprising iron and unavoidable impurities, the volume fraction γR of residual austenite at the crossing point depth is 0.1-8.0 vol%, where the crossing point is the depth from the surface, on the coil inside diameter side of an arbitrary cross section of an effective portion of the coil spring, at which the value of the compressive residual stress when unloaded is zero in the substantially maximum principal stress direction when a compressive load is applied to the spring, and the average hardness at the crossing point depth is 570-700 HV.
Inventors:
OKABE SATOSHI (JP)
SHIRAISHI TOHRU (JP)
TAKAHASHI KEITA (JP)
HIRAI SHUN (JP)
MIZUMOTO MASATAKA (JP)
SHIRAISHI TOHRU (JP)
TAKAHASHI KEITA (JP)
HIRAI SHUN (JP)
MIZUMOTO MASATAKA (JP)
Application Number:
PCT/JP2022/046674
Publication Date:
June 29, 2023
Filing Date:
December 19, 2022
Export Citation:
Assignee:
NHK SPRING CO LTD (JP)
International Classes:
C21D7/06; C21D9/02; C22C38/00; C22C38/04; C22C38/54; F16F1/02
Domestic Patent References:
| WO2014136966A1 | 2014-09-12 |
Foreign References:
| JP2021167444A | 2021-10-21 | |||
| JP2018178184A | 2018-11-15 | |||
| JP2014206219A | 2014-10-30 | |||
| JP2009052144A | 2009-03-12 |
Attorney, Agent or Firm:
SUENARI, Mikio (JP)
Download PDF:
Previous Patent: HARD COAT FILM
Next Patent: ROBOT CONTROL DEVICE, ROBOT SYSTEM, AND ROBOT CONTROL PROGRAM
Next Patent: ROBOT CONTROL DEVICE, ROBOT SYSTEM, AND ROBOT CONTROL PROGRAM