Vented hubcap

A hubcap for covering lubricated wheel bearings in a wheel hub comprising:

• a hubcap body member attachable to the wheel hub for enclosing the wheel bearings, said hubcap member defining a closed chamber between said hubcap body member and the wheel hub for housing a fluid for lubricating the wheel bearings;
• a vent means for permitting gases to flow from said chamber, said vent means including a vent passage extending through said hubcap body member and a thin sheet of porous material supported on said hubcap body member for allowing a flow of gases to enter and exit said chamber through said vent passage while preventing liquids and other contaminants from flowing into said chamber and lubricant from flowing out of said chamber, said sheet of porous material including an outer surface exposed to external contaminants;
• a fastening means attached to said hubcap body member and covering said sheet of porous material, said fastening means including means for securing said sheet of porous material in position over said vent passage, said sheet of porous material being positioned between said fastening means and said vent passage, said fastening means defining a central cavity located adjacent said outer surface of said sheet of porous material and at least one port extending radially from said central cavity to connect said central cavity to the atmosphere, said central cavity operating to shield said outer surface of said sheet of porous material from exposure to the external contaminants;
• and
• filtering means connected to said hubcap body for preventing the passage of contaminants through said port to thereby prevent the accumulation of such contaminants on said sheet of porous material.