| 摘要 |
PURPOSE:To reduce the dimension of the leg part, maintaining the strength of an installation metal fitting, by forming the leg part of the installation metal fitting of a spark plug into cylindrical surface having a small diameter and press-fixing the shoulder part of the installation metal fitting by a pressing tool fastened onto the outer surface of a cylinder head. CONSTITUTION:A spark-plug installation hole 15 is formed at the position surrounded by two suction valves 13 and two exhaust valves 13 at the top part of the combustion chamber 17 of each cylinder on a cylinder head 12. The installation metal fitting 2 of a spark plug 20 having a cylindrical leg part 22 having an outside diameter of 10mm or less is fitted into the installation hole 15. Further, the shoulder part of the spark plug 20 is fixed by the pressing by a pressing tool 5 fastened onto the outer surface of the cylinder head 12. Therefore, the dimension of the leg part can be reduced to the min., maintaining the strength of the installation metal fitting. |
