Method for producing spring
US9623475B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 12, 2011 |
| Grant date | Apr 18, 2017 |
| Priority date | — |
| Expiry date | Nov 29, 2033 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49609
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A method of producing a spring which reduces time required for a heat treatment step of eliminating a machining strain generated by a forming step is provided. This production method is provided with a forming step (S10) of forming a spring steel material into a spring shape and a heat treatment step (S12) of eliminating a machining strain generated in the spring steel material by the forming step. The heat treatment step is executed by electrically heating the spring steel material by applying a current thereto. The heat treatment step has a first step of heating the spring steel material to a predetermined set temperature and a second step of keeping the spring steel material at the set temperature for a predetermined set time period subsequent to the first step. The set temperature is set to be higher than 430° C. but not higher than 500° C.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.