Spark plug
US9620935B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 10, 2014 |
| Grant date | Apr 11, 2017 |
| Priority date | — |
| Expiry date | Oct 10, 2034 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01T13/58
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A packing between an insulator and a metal shell of a spark plug. A length between a first position of a contact portion of the packing and the insulator and a second position of a contact portion of the packing and the insulator parallel to an axial line direction is set as a first length. In the case where a load perpendicular to the axial line direction is applied to the second position, a ratio of stress at a surface position that is a position on a surface of the insulator to stress at the first position is set as a stress ratio. In a range of the surface position where the stress ratio is 0.8 or more to 1.15 or less, a length in a continuous range from the first position toward a front end side parallel to the axial line direction is set as a second length. A ratio of the second length to the first length is 0.7 or more.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.