| 摘要 |
A spark plug with an outer electrode for internal combustion engines is provided to secure the heat resistance and shatter resistance of an outer electrode while improving ignitability. A spark plug(100) comprises a cylindrical fitting(110), a cylindrical isolator(120) and an electrode. The cylindrical fitting having a leading end surface and a stylobate is formed in an axial direction. The isolator having the leading end surface, the stylobate and a protruded isolating part is supported by the cylindrical fitting. The electrode is supported by the isolator and protruded from the leading end surface of the cylindrical fitting. A central electrode includes a central electrode leading end part with an outer circumference. The outer electrode substrate has the stylobate and a leading end part. The leading end surface of an outer electrode tip is located at a distance from the outer circumference of the central electrode leading end part. The isolator is protruded at least 1.0mm from the leading end surface of the fitting.
|
