| 摘要 |
PURPOSE:To discharge surely the gas from the inside of a product part by providing a vent passage and a bypass passage which is branched from the vent passage and opens to the outside of dies to a stationary die or movable die and providing a valve disc for discharging gas to a core thereby opening the bypass valve in the stage of die clamping and shutting off the passage by the pressure of a molten metal. CONSTITUTION:A core 10 is lowered and a stationary die 11 and a movable die 12 are clamped so as to sandwich the core 10. A poppet valve 17 is seated to one end of a vent passage 15 to shutt off a vent passage 15 and on the other hand, a bypass passage 16 is opened via an aperture 19 and a gas discharge groove 20 to the outside of the dies. When a molten metal is poured under pressure into a product part 13, the gas in the part 13 is discharged through the passage 16, the aperture 19 and the groove 20 to the outside of the dies. When the molten metal is pushed up to the passage 15 at the end period of pouring the molten metal, the valve 17 is forced upward by the pressure of the molten metal, by which the passage 15 is opened and the passage 16 is shut off. |
