| 摘要 |
PROBLEM TO BE SOLVED: To improve strength by forming a flow passage for a synthetic resin on an inner or outer diameter side of a holder correspondingly to a pocket of the holder, without interfering with the pocket at the time of injection molding, injection-molding the holder, and then removing the flow passage for the synthetic resin. SOLUTION: Resin 2 is charged from a gate 4 formed on a disc 3. The resin 2 charged from the gate 4 is flowed through a flow passage 6 formed on an inner diameter side of a pocket 5. Due to the presence of the flow passage 6, the resin 2 is smoothly charged to the opposite side to the gate in each pocket. Weld is generated partially in the pocket, so that strength is improved. The pocket 5 can be formed by arranging a slide core type die. A disc gate method is selected as a charging method. In such a case, flow of the resin is terminated at a disc end. Clear weld is hardly generated, for easily securing improvement of strength. |
