| 摘要 |
PROBLEM TO BE SOLVED: To prevent the degradation of vacuum degree in a cavity before charging molten metal and to restrain the occurrence of flash by restraining gas pressure in the cavity at the charging time of the molten metal. SOLUTION: This vent device is used for a die casting machine by which the molten metal charged in a sleeve is pressed into the cavity in a die by a plunger. A vent block 3 and a vent valve main body 4 are inserted attachably/ detachably to/from the die separating end of a movable die 1 and a fixed die 2. In the vent valve main body 4, a valve vacuum path 7 and a vacuum vent path 8 communicated with the cavity are provided, and the valve vacuum path 7 is closed with a shut valve 10 linked with the action of the plunger. Further, the vent block 3 is pushed to the vent valve main body 4 by a disk spring 17, and in the ordinary time, a vent path 14 is closed, but when the gas pressure in the cavity becomes a prescribed value or above by pressing the molten metal, the vent path 14 is formed by the gas pressure.
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