| 摘要 |
<p>The metallic shell (20) of a glow plug has a cylindrical male-threaded portion (21) and a tightening portion (22). The tightening portion (22) is formed to have an outer circumferential surface of a shape corresponding to that of a 12-point nut. By virtue of this structure, the tightening portion (22) can have a greater wall thickness as compared with a conventional tightening portion which has a an outer circumferential surface of a shape corresponding to that of a hexagon nut. Therefore, it becomes possible to made the glow plug thinner, while maintaining the strength of the tightening portion (22). <IMAGE> <IMAGE></p> |
