| 摘要 |
PROBLEM TO BE SOLVED: To suppress the generation of damage, etc., by arranging a gate of a synthetic resin filling mold at a position facing to a cavity side surface, which forms a ring end surface of a holder or a ring end surface near a support, and forming a device with injection molding. SOLUTION: A mold for injection molding of a synthetic resin cage is formed of an outside mold 2, an inside mold 3, a lower mold 4, an upper mold 5. A gate G is arranged in the upper mold 5 at a position facing to a cavity 6 side surface as a column part 1b. When the synthetic resin, in which glass fiber is mixed and which is melted, is filled from the gate G, the synthetic resin is divided into right and left so as to flow and join inside the cavity 6, and hardened in the condition that the short glass fiber as the reinforcing material is arranged in the column 1b direction. An impact of rollers applied to the column part 1b, and even in the case where the concentration of the stress is generated at a corner 8 between the column part 1b and a ring part 1a, since the glass fiber inside thereof is arranged in the direction opposite to the stress, generation of crack or the like is checked. |
