Motor vehicle seal assembly and method of manufacture

Abstract

A motor vehicle has a first body part with a seal support flange thereon that supports a unitary seal construction having a flexible bulb seal portion engageable with second vehicle body part including a hood or other vehicle body part for sealing against leakage between the first and second vehicle body parts and an integrally formed base portion and wherein the flexible bulb seal is hollow and is formed of a soft low density thermoplastic foam and the integrally formed base portion is integrally extruded with the flexible bulb seal and is formed solely from polymeric material having spaced walls defining a recess for fitting the unitary seal construction in place on the support flange.

We claim:  
     
         1 . A method for making a tripartrite seal comprising: 
 providing a die having first, second and third regions for forming, respectively, a bulb seal, a rigid base and a connection there between;    providing first, second and third plastic materials;    and coextruding the first, second and third plastic materials, respectively through said first, second and third regions for forming a three-piece integral seal assembly.    
     
     
         2 . The method of  claim 1  wherein said first material is comprised of a soft low-density thermoplastic elastomer foam.  
     
     
         3 . The method of  claim 2  wherein said first material is further characterized as having a density in the range of 20-60 lbs./ft. cubed.  
     
     
         4 . The method of  claim 2  wherein said third material is comprised of a thermoplastic elastomer.  
     
     
         5 . The method of  claim 4  wherein said third material is still further characterized as being polypropylene.  
     
     
         6 . The method of  claim 4  wherein said third material is still further characterized as a thermoplastic elastomer having a specific gravity between 0.3-0.6.  
     
     
         7 . The method of  claim 4  wherein said second material is comprised of a thermoplastic elastomer including a foaming agent.  
     
     
         8 . The method of  claim 1  where in said base is formed solely from polymeric material and wherein said base has spaced sides with a bight portion co-extruded with said flexible foamed seal and spaced sides have inner walls containing an adhesive bead that flows over a support member as thin bond layer to provide intimate contact and adhesion between the base and the support member.  
     
     
         9 . The method of  claim 1  wherein said base is formed solely from polymeric material and wherein said base has spaced sides with a bight portion co-extruded with foamed seal portion and including wing members and wherein the spaced sides have smooth inner walls that are biased together to clamp against a support member located there between.  
     
     
         10 . The method of  claim 1  wherein an additional extrusion is applied as a coating material on part or all of the exterior perimeter of said flexible foamed seal.  
     
     
         11 . The method of  claim 10  wherein said coating material is a wear resistant material selected from the group consisting of TPE; polyurethane polymers; thermoplastic polyester; nylon resins; melt processable rubbers; and TPF fluorocarbon.  
     
     
         12 . The method of  claim 10  wherein said coating material is a friction reducing material from the group consisting of TPE fluorocarbon; polyethylene; high-density polyethylene; synthetic polymers which contain particulate lubricants, optionally powdered ultra high molecular weight polyethylene, powdered PTFE, mica, graphite or molybdenum; and blends or alloys of synthetic polymers which contain particulate lubricants.  
     
     
         13 . The product of the method of  claim 1.