| 摘要 |
PURPOSE:To avoid both the damage to the deck face and flattening of a bead and offer the stable sealing effect by forming the bead of a base plate in the stepped form and placing a compensation part having the specified thickness at the position on the side of the hole of a combustion chamber. CONSTITUTION:Primary and secondary base plate 6 and 8 laid both on and under an intermediate plate 4 surround a combustion chamber hole 10 and have the primary and the secondary bead 14 and 16, respectively. The plate 4 has a compensation part 20 of the specified thickness at the position nearer to the combustion chamber hole 10 than the bead portion 18 including both the primary and the secondary stepped beads 14 and 16. As a result, the spring constant of the beads is generally reduced so that both the damage to the deck surface and the flattening of the beads may be avoided and the surface pressure may act uniformly. Therefore, the durability and the sealing performance is able to be improved and the irregular gap between deck faces around the combustion chamber, produced at the time of tightening be compensated. |
