Spark plug
US9225150B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 16, 2013 |
| Grant date | Dec 29, 2015 |
| Priority date | — |
| Expiry date | Jul 16, 2033 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01B3/12
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A spark plug includes an insulator including an axial hole and having an outer periphery with a tapered outer face; a metal shell having a thread portion and a tapered inner face; and a circular packing sandwiched between the tapered outer face of the insulator and the tapered inner face of the metal shell. On at least one cross section including the axis, (A/B)≧3.1, B≧0.25, and (A+B)≦2.0 are satisfied, where A represents a length of (a difference between an effective diameter of the thread portion and an inner diameter at a rear end of the tapered inner face)/2, and B represents a length of (a difference between the inner diameter at the rear end of the tapered inner face and an inner diameter at a front end of the tapered inner face)/2.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.