Minimal differential pressure venting system

Abstract

A power train assembly includes a housing having a exterior wall that defines a partition between an internal chamber and the environment. Portions of the exterior wall define a housing aperture within the exterior wall. A vent plug engages the portions of the exterior wall that define the housing aperture. Portions of the vent plug define a vent aperture that is smaller than the housing aperture.

What is claimed is:  
     
         1 . A power train assembly comprising: 
 a housing having a exterior wall defining a partition between an internal chamber and the environment, portions of said exterior wall defining a housing aperture forming a passageway between said internal chamber and the environment;    a power train member located within said housing; and    a vent plug engaging said portions of said exterior wall that define said housing aperture, said vent plug including portions defining a vent aperture, smaller than said housing aperture, within said vent plug.    
     
     
         2 . The power train assembly of  claim 1  wherein said vent aperture is coaxial with said housing aperture.  
     
     
         3 . The power train assembly of  claim 1  wherein said vent aperture and said housing aperture are concurrent and coaxial within said housing.  
     
     
         4 . The power train assembly of  claim 1  wherein said exterior wall includes an exterior surface and an interior surface, said vent aperture being positioned outboard of said exterior surface.  
     
     
         5 . The power train assembly of  claim 1  wherein said exterior wall includes an exterior surface and an interior surface, said vent aperture being positioned inboard of said interior surface.  
     
     
         6 . The power train assembly of  claim 1  wherein said exterior wall includes an exterior surface and an interior surface, said vent aperture being positioned between said exterior surface and said interior surface.  
     
     
         7 . The power train assembly of  claim 1  wherein said vent plug an outwardly extending conical nozzle, said vent aperture being defined within said nozzle.  
     
     
         8 . The power train assembly of  claim 7  wherein said exterior wall includes an exterior surface and an interior surface, said vent aperture being positioned outboard of said exterior surface.  
     
     
         9 . The power train assembly of  claim 7  wherein said exterior wall includes an exterior surface and an interior surface, said vent aperture being positioned inboard of said interior surface.  
     
     
         10 . The power train assembly of  claim 7  wherein said exterior wall includes an exterior surface and an interior surface, said vent aperture being positioned between said exterior surface and said interior surface.  
     
     
         11 . The power train assembly of  claim 1  wherein said exterior wall includes portions defining at least one additional housing aperture, within said exterior wall, and an additional vent plug engaging said portions of said exterior wall that define each of said additional housing apertures, portions of each of said additional vent plug defining a vent aperture, smaller than said housing aperture.  
     
     
         12 . The power train assembly of  claim 1  wherein said housing aperture includes an inner surface and said vent plug includes an outer surface, substantially the same shape as said inner surface of said housing aperture, said outer surface of said vent plug being sized slightly smaller than said inner surface of said housing aperture such that when said vent plug is pressed into said housing aperture there is an interference fit between said inner surface of said housing aperture and said outer surface of said vent plug such that said vent plug is frictionally held within said housing aperture.  
     
     
         13 . The power train assembly of  claim 1  wherein said vent plug includes an annular flange extending radially from said vent plug, said annular flange being adapted to engage an outer surface of said exterior wall and provide a stop to position said vent plug within said housing aperture.  
     
     
         14 . The power train assembly of  claim 1  wherein said vent aperture is round.  
     
     
         15 . The power train assembly of  claim 1  wherein said vent aperture has an area that is approximately 1.8 square millimeters or less.