| 摘要 |
PURPOSE:To improve a sealing property as well as reliability by folding back a sub- plate which is laminated on a base plate and forming a fold-back part, overlapping the end edge of said sub-plate on the end edge face of said base plate forming a compensating part of a defined thickness, and separating the end face of the end edge of said base plate from the innermost part of said fold-back part of said sub-plate by a defined distance. CONSTITUTION:A compensating part 14 of a defined thickness is formed toward a combustion chamber hole side from the bead site of a bead 12 which is provided around a combustion chamber hole 8. Thereby, a large deck face gap around a combustion chamber can be compensated, the expansion and contraction of the deck face gap due to the effect of combustion gas pressure or engine heat can be prevented, and an alternate load which acts on the bead can be lowered, preventing the permanent set of the bead. The periphery of the combustion chamber is surrounded by both the compensating part and the bead site thereby preventing the leakage of combustion gas with high efficiency. Further, when the bead of the base plate 4 is compressed and deformed due to a clamping force, the end face of the end edge of the base plate is not brought into contact with the fold-back part of a sub-plate 6 due to a defined distance L which is provided in between the end face of the end edge of the base plate and the innermost part of the fold-back part, preventing damage to these parts.
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