| 摘要 |
A multilayer metal gasket has a pair of outer active layers separated by an intermediate layer. The outer active layers are formed with at least one pair of aligned apertures and sealing beads surrounding the apertures in radially outwardly spaced relation thereto presenting laterally opposed sealing surfaces of the active layers of predetermined spacing or thickness when the gasket is in a compressed free state. The intermediate layer extends radially inwardly beyond the apertures and is provided with a cold formed stopper portion having a thickness greater than the combined material thicknesses of the intermediate layer and outer active layers but less than the thickness of the sealing beads. The stopper portion is cold formed under a compressive load exceeding the compressive load required to deform the sealing beads beyond their elastic limit, thereby preventing irreversible damage to the sealing beads. The stopper portion presents opposing sealing surfaces which, when the gasket is clamped between two members having a passage to be sealed, serves as a primary seal or fire dam, shielding the sealing beads of the outer active layers from direct exposure to the heat of any fluid in the passage, such as hot exhaust gases of an internal combustion engine.
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