STRESS NEUTRALIZATION OF AN APEX FILLER FOR A TIRE BEAD SUBASSEMBLY

摘要

A method and apparatus are provided for a sub forming an elastomeric extrusion into a bead apex filler and for applying the same to an annular bead (120) to form a bead/apex subassembly for use in the construction of a pneumatic tire. The apex filler (100) is formed from a triangular shaped extrusion (8) that is initially wrapped around a rotating mandrel (40) having a diameter of between about 50 % to about 75 % of the outer diameter of the annular bead to which the filler is attached. A helical former (50, 60) disposed around the mandrel causes the extrusion to move in a helical path as it traverses the mandrel. As the extrusion is removed from the mandrel, the extrusion is sufficiently uncoiled to relieve and compressive or tensile stresses. Then, the partially uncoiled extrusion is wrapped around the outer periphery of the bead to form a bead/apex filler subassembly (118) which is substantially without compressive or tensile stresses when mounted onto the tire being constructed.