发明名称 |
SPARK PLUG FOR INTERNAL COMBUSTION ENGINE |
摘要 |
There is provided a spark plug for an internal combustion engine, including: a center electrode extending in the direction of an axis of the spark plug and having a core of higher thermal expansion coefficient than that of a front end thereof, the center electrode including a flanged portion radially outwardly protruding on a rear side thereof and a cylindrical portion located closer to a front end of the spark plug than the flanged portion and being smaller in diameter than the flanged portion; an insulator having an axial hole in the direction of the axis to retain the flanged portion in the axial hole with the cylindrical portion held in a loose-fit state in the axial hole; and a metal shell accommodating the insulator, wherein the spark plug satisfies the following condition: Cb < Cf where Cb is a difference between an inner diameter of the axial hole and an outer diameter of the cylindrical portion at an arbitrary axial position B in the direction of the axis; and Cf is a difference between the inner diameter of the axial hole and the outer diameter of the cylindrical portion at an axial position F closer to the front end of the spark plug than the axial position B in the direction of the axis. |
申请公布号 |
EP2180565(A1) |
申请公布日期 |
2010.04.28 |
申请号 |
EP20080776988 |
申请日期 |
2008.05.29 |
申请人 |
NGK SPARK PLUG CO., LTD. |
发明人 |
KISHIMOTO, KAORI;NAKAYAMA, KATSUTOSHI;KAMEDA, HIROYUKI;AOKI, TOMOAKI |
分类号 |
H01T13/20;H01T13/16 |
主分类号 |
H01T13/20 |
代理机构 |
|
代理人 |
|
主权项 |
|
地址 |
|