Fuel sealing structure

Abstract

To provide a fuel sealing structure capable of preventing the leakage of not only liquid fuel but also gasified fuel, an annular packing 30 is interposed between an annular sealing surface 15 on an opening part 11 of a container 20 and an annular sealing surface 25 of a closure 20 . The distance between the second regions 15 b, 25 b of the sealing surfaces 15, 25 is shorter than that between the first regions 15 a, 25 a . The packing 30 includes a first sealing part 31 sandwiched between the first regions 15 a, 25 a and a second sealing part 32 sandwiched between the 15 b, 25 b . The second sealing part 32 is smaller in thickness than the first sealing part 31 and the difference of the thicknesses is larger than the difference of distances between the above-mentioned regions. With the closure 20 attached, the compression ratio of the second sealing part 32 is smaller than that of the first sealing part 31.

1 . A fuel sealing structure comprising a container for storing fuel and having an opening part, a closure attached to the opening part of said container, and an annular packing interposed in a compressed condition between an annular sealing surface of said opening part of said container and an annular sealing surface of said closure, wherein 
 said sealing surfaces of said container and closure each include an annular first region and an annular second region, and a distance between said second regions of said two sealing surfaces is shorter than that between said first regions,    said packing includes a first sealing part sandwiched between said first regions of said two sealing surfaces and a second sealing part sandwiched between said second regions of said two sealing surfaces, said first and second sealing parts are, in their compressed condition, interposed between said sealing surfaces, said second sealing part is smaller in thickness than said first sealing part in a natural condition, and this difference in thickness is larger than the difference between said distance between said first regions and said distance between said second regions.    
   
   
       2 . A fuel sealing structure according to  claim 1 , wherein a compression ratio of said second sealing part is smaller than that of said first sealing part when said closure is in an attached condition.  
   
   
       3 . A fuel sealing structure according to  claim 1  or  2 , wherein said first sealing part is located radially inside of said second sealing part.  
   
   
       4 . A fuel sealing structure according to  claim 1  or  2 , wherein one of said sealing surfaces of said container and closure is a plane with said first and second regions made flush with each other, and the other sealing surface includes a step at a boundary between said first and second regions, 
 one surface of said packing is a plane corresponding to said one sealing surface, and the other surface includes a step corresponding to the other sealing surface.    
   
   
       5 . A fuel sealing structure according to  claim 1  or  2 , wherein an annular projection is formed on one of said sealing surface of said container and said sealing surface of said closure, a top surface of said projection is provided as said second region, a radial inside and a radial outside of said projection in said one sealing surface are provided as said first regions, the other sealing surface includes said second region and said first regions disposed radially inside and outside of said second region on a same plane in correspondence to one sealing surface, and said packing includes said thin second sealing part corresponding to said projection and said thick first sealing parts located radially inside and outside of said second sealing part.