| 摘要 |
PURPOSE:To contrive a reduction in weight while maintaining the various running capacities of a tire, by a method wherein rubber for a bead apex possessing a plurality of holes extending in a circumferential direction of the tire by making use of a specific rubber extruding device and the extruded crude bead apex is prevulcanized prior to assembly of a crude cover. CONSTITUTION:Rubber for a bead apex is kneaded and a substrate 4 provided with a rubber passing through hole 3 and a plurality of pin materials 5 having the diameter of 1-3mm to be arranged within the rubber passing through hole 3 are provided. Then the rubber kneaded by making use of an extruding device of the bead apex possessing an extruding nozzle 2 wherein a ratio SIGMAs/S of an opening area S of an extruding port 6 of the rubber passing through hole 3 and the sum total SIGMAs of a sectional area of a pin material at the extruding port 6 is taken as 0.1-0.7 is extruded. Then prevulcanization is performed to perform shape retension of the extruded bead apex. The same is incorporated into a crude cover and assembly and the crude cover are vulcanization-molded. It is preferable that a vulcanization time is taken as 45 minutes to obtain a property value of the rubber. |
