Spark plug having particular insulator
US8093791B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 26, 2009 |
| Grant date | Jan 10, 2012 |
| Priority date | — |
| Expiry date | Dec 5, 2029 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC04B2235/96
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An object of the invention is to provide a spark plug including an insulator which is difficult to cause breakdown and exhibits higher withstand voltage characteristics. This invention relates to a spark plug 1 including a center electrode 2, an insulator 3 and a grounding electrode 6, wherein the insulator is formed by an alumina-based sintered body which has a theoretical density ratio of 95.0% or more, which contains a rare earth element component, Si component, and at least two kinds of Group 2 element (2A) components, and in which the rare earth element being dispersed so as to satisfy the following condition: <Condition> when 7 places of measurement line (measurement length: 180 μm) are selected in the alumina-based sintered body and the rare earth element (RE) present in each of selected measurement lines is analyzed with an energy dispersion method, a total number of measurement lines in which 8 or more peaks derived from the rare earth element (RE) are observed is 4 places or more of the 7 places.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.