Coil spring for vehicle suspension and method for manufacturing the same
US8308150B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 26, 2010 |
| Grant date | Nov 13, 2012 |
| Priority date | — |
| Expiry date | Mar 26, 2030 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49611
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A spring wire with hardness of 50 to 56 HRC is subjected to first and second shot peening processes within a warm working temperature range of 150 to 350° C. In the first shot peening process, the first shot of a shot size of 1.0 mm or more is used. In the second shot peening process, the second shot smaller in shot size than the first shot is used. Through these shot peening processes, compressive residual stress is imparted to the spring wire. The spring wire includes a residual stress increase part, residual stress peak part, and residual stress decrease part. In the residual stress decrease part, a part including the compressive residual stress magnitude of which is equivalent to the magnitude of the compressive residual stress at the surface of the spring wire exists at a position at a depth exceeding the permissible pit depth.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.