| 摘要 |
PURPOSE:To effect easily high pressure injection molding, especially precision injection molding by operating hydraulic pressure that is boosted by a pressure augmenting cylinder only during the pressure preservation process and keeping pressure during the pressure preservation process higher than the maximum pressure during the injection. CONSTITUTION:When, after filling, the change-over valve moves to the position (a) to change-over for the pressure preservation process, hydraulic pressure from a hydraulic source 13 works on the oil chamber 10 of a pressure boosting cylinder 7. The oil pressure in the oil chamber 11 of an injection cylinder 3 is kept in by check valves 11 and 15, and the hydraulic pressure is multiplied by (d4/d3)<2> through the larger diameter d4 and smaller diameter d3 of a piston 8, and a piston 4 of the injection cylinder 3 stays as pushed forward until the pressure preservation is completed. |
