| 摘要 |
The molding pressure in a cavity (3) when a molding rubber material (4) is filled thereinto is appropriately maintained, thereby effectively preventing the occurrence of defective molding. Specifically, a base material (11) is set and clamped between split molds (22, 23) of a mold (2). The molding rubber material (4) is injected into the cavity (3), the cavity having an endless shape and defined between the surface of the base material (11) and the inner surface of the split mold (22) facing thereto. The injection amount thereof is set to an amount such that after the cavity (3) is filled with the molding rubber material (4), the molding rubber material flows from an air vent hole (36) bored at a confluence position (3a) of the molding rubber material (4) in the cavity (3) into a surplus material reservoir (38) provided downstream from the air vent hole and the surplus material reservoir (38) is not filled therewith. The pressure drop due to flow resistance is caused to the molding rubber material (4) flowing from the air vent hole (36) into the surplus material reservoir (38), and by the pressure drop, the pressure in the cavity (3) is maintained at a value higher than or equal to the lower limit of the pressure required to mold a gasket (12) and lower than the lower limit of the pressure at which leakage from the cavity (3) occurs. |
