Method for manufacturing a coil spring for vehicle suspension
US8533954B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 10, 2011 |
| Grant date | Sep 17, 2013 |
| Priority date | — |
| Expiry date | Dec 7, 2031 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49611
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A spring wire with a hardness of 50 to 56 HRC is subjected to first and second shot peening processes within a warm working temperature range of 150° C. to 350° C. In the first shot peening process, a first shot of a shot size of at least 1.0 mm is used. In the second shot peening process, a 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 a compressive residual stress magnitude equivalent to the magnitude of the compressive residual stress at a surface of the spring wire exists at a region at a depth exceeding the permissible pit depth.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.