| 摘要 |
PROBLEM TO BE SOLVED: To prevent a bare from being generated and at the same time, realize the enhancement of productivity by making the bumping unnecessary and at the same time, the reduction of the wasteful consumption of a material by curtailing the overvolume, in a method for manufacturing a rubber sphere and a rubber sphere manufacturing device. SOLUTION: A mouthpiece 2 is provided which has two or more and 12 or less protrusions 12 directed toward the axial center implanted on the inner peripheral face of a circular hole part 7 in such a way that the protrusions 12 are equally distributed circumferentially as viewed from the axial center L direction of the hole part 7. A groove part in parallel with a rubber extrusion direction is formed in a position, corresponding to the protrusions 12, of the rubber on its outer peripheral face, while the rubber is extruded from the hole part 7 of the mouthpiece 2. Further, the rubber is cut to the specified size to obtain short columnar preliminary moldings with a groove part. In addition, the preliminary molding is compression-molded and vulcanized into a spherical shape using a pair of hemispherical halves of a mold to obtain a rubber sphere. |
