Spark plug and method of manufacturing same
US6653766B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | May 10, 2001 |
| Grant date | Nov 25, 2003 |
| Priority date | — |
| Expiry date | Jun 23, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01T21/02
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A spark plug for an engine comprises a mounting member to be mounted to an engine, an insulator disposed inside the mounting member and formed with an axial hole, a center electrode formed of a metal material and disposed in the axial hole of the insulator in a manner insulated from the mounting member, and an earth electrode disposed so as to oppose to the center electrode. At least one of the center electrode and earth electrode is formed as a base material having one surface to which a tip composed, as a discharge member, of a noble metal or alloy thereof is welded and fixed thereto through a fused portion. The fused portion between the tip and the base material has an area of a maximum sectional area portion of a size of not more than 1.5 times a sectional area of a portion of the tip positioned at a boundary portion to the fused portion, and the sectional area of the tip positioned at the boundary portion is not less than 2 mm2 and not more than 7 mm2.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.