| 摘要 |
PROBLEM TO BE SOLVED: To improve withstand voltage of a spark plug.SOLUTION: A spark plug 1 for an internal combustion engine comprises: a columnar center electrode 100 having a discharging part 150; a cylindrical insulator 300 for holding the center electrode 100 on an inner peripheral side; a cylindrical housing 400 for holding the insulator 300 on an inner peripheral side; and a ground electrode 200 extending from the housing 400 and opposed to the discharging part 150. Spark is discharged in a spark discharging gap P between the discharging part 150 and the ground electrode 200. The center electrode 100 has: a columnar axial core part 110 made of a conductive material and provided with the discharging part 150; a cylindrical protection part 130 made of a conductive material, covering the axial core part 110 from an outer peripheral side, and covered by the insulator 300 from the outer peripheral side; and a cylindrical insulation part 120 made of an insulation material and provided between the axial core part 110 and the protection part 300. |
