| 摘要 |
PURPOSE:To improve productivity without using an adhesive by decreasing a mold pressing pressure applied on the peripheral part of a cone set in a mold, injecting unvulcanized rubber to form a thin film on the peripheral part of the cone to form the edge. CONSTITUTION:An upper mold 9, in its part where the cone 11 is loaded, is so constituted that a cone peripheral part abutting part 9a is recessed slightly from other cone peripheral part abutting part 9b via a step part 9c. The cone 11 is sandwiched by the upper mold 9 and a lower mold 8. When the unvulcanized rubber is injected, the part 9a is subjected to a mold pressing pressure lower than that applied on the part 9b. The said rubber constituting the edge intrudes the clearance at the part 9a is stuck integrally to periphery of the edge as a film 21. Thereafter, the edge 20 which is connected integrally with the periphery of the cone is formed. In such a way, a strong adhesion is generated without a necessity for an adhesive, and the productivity is improved.
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