Metal gasket

Abstract

A metal gasket capable of preventing the occurrence of cracks in a stopper while employing a wave-shaped stopper, improving the contact pressure balance around the bead to enhance the engine performance, and improving the durability of the stopper. The metal gasket is constituted by a gasket component sheet having an opening formed to face a combustion chamber, and the gasket component sheet is provided with a combustion chamber bead surrounding the opening. An inner circumference side stopper lower than the height of the combustion chamber bead is formed along the combustion chamber bead in a portion between the combustion chamber bead and the opening such that at least a section of each wave where stress amplitude is large becomes thin, a thin portion and a thick portion are arranged alternately in each wave, and the hardness of the thin portion is higher than that of the thick portion.

1 . A single-layer or multiple-layer metal gasket composed of a single or a plurality of gasket component sheet(s) having an opening formed to face a combustion chamber of an engine, at least one of the gasket component sheets being provided with a bead surrounding the opening, 
 wherein an inner circumference side stopper for preventing the bead from collapsing is formed at least either in a portion between the bead and the opening of the gasket component sheet formed with the bead or in a portion of another gasket component sheet opposing the same;    an outer circumference side stopper for preventing the bead from collapsing is formed at least either in a portion on the outer side from and close to the bead in the gasket component sheet formed with the bead or in a portion of another gasket component sheet opposing the same; and    the inner circumference side stopper is constituted by a plurality of auxiliary beads which are formed along the bead in the peripheral edge of the opening in the gasket component sheet such that the inner circumference side stopper is formed by these auxiliary beads into a wave-shaped cross section lower than the height of the bead.    
   
   
       2 . The metal gasket according to  claim 1 , wherein the outer circumference side stopper is provided by dividing the gasket component sheet to be provided with the outer circumference side stopper into an inner circumference side component sheet located close to the opening and an outer circumference side component sheet corresponding to the other part of the gasket component sheet and partially overlapping the inner circumference side component sheet and the outer circumference side component sheet to form the outer circumference side stopper.  
   
   
       3 . The metal gasket according to  claim 1 , wherein the outer circumference side stopper is provided by forming a build-up portion from a material having thermal resistance and compressive resistance.  
   
   
       4 . The metal gasket according to  claim 1 , wherein the outer circumference side stopper is provided by welding a ring-shaped stopper plate.  
   
   
       5 . The metal gasket according to  claim 1 , wherein the outer circumference side stopper is provided by forming a plurality of auxiliary beads along the bead such that the outer circumference side stopper is formed by these auxiliary beads into a wave-shaped cross section lower than the height of the bead.  
   
   
       6 . The metal gasket according to  claim 1 , wherein the stoppers formed by the plurality of auxiliary beads into a wave-shaped cross section are formed along the bead such that a section of each wave where stress amplitude is large becomes thin, a thin portion and a thick portion are arranged alternately in each wave, and the hardness of the thin portion is higher than that of the thick portion.  
   
   
       7 . The metal gasket according to  claim 2 , wherein the stoppers formed by the plurality of auxiliary beads into a wave-shaped cross section are formed along the bead such that a section of each wave where stress amplitude is large becomes thin, a thin portion and a thick portion are arranged alternately in each wave, and the hardness of the thin portion is higher than that of the thick portion.  
   
   
       8 . The metal gasket according to  claim 3 , wherein the stoppers formed by the plurality of auxiliary beads into a wave-shaped cross section are formed along the bead such that a section of each wave where stress amplitude is large becomes thin, a thin portion and a thick portion are arranged alternately in each wave, and the hardness of the thin portion is higher than that of the thick portion.  
   
   
       9 . The metal gasket according to  claim 4 , wherein the stoppers formed by the plurality of auxiliary beads into a wave-shaped cross section are formed along the bead such that a section of each wave where stress amplitude is large becomes thin, a thin portion and a thick portion are arranged alternately in each wave, and the hardness of the thin portion is higher than that of the thick portion.  
   
   
       10 . The metal gasket according to  claim 5 , wherein the stoppers formed by the plurality of auxiliary beads into a wave-shaped cross section are formed along the bead such that a section of each wave where stress amplitude is large becomes thin, a thin portion and a thick portion are arranged alternately in each wave, and the hardness of the thin portion is higher than that of the thick portion.