| 摘要 |
PURPOSE:To improve the quality of a product by providing a speed detector for an injection piston, disposing a pressure boosting speed control valve and acutating a pressure boosting piston. CONSTITUTION:The pressure side of the injection piston 12 is connected via a check valve 26 and a speed control valve 28 to a hydraulic source 30. The pressurization side of the pressure boosting piston 14 is connected via the pressure boosting speed control valve 32 to the source 30. A speed detecting sensor 34 is provided to one side of a piston rod 16 and is connected to the speed detector 36. The decrease of the speed of the piston 12 down to a prescribed value or below is detected by the speed detector 36 and a speed change discriminator 38 when such state arises in the stage of packing a molten metal into a cavity 20. The valve 32 is then operated to actuate the piston 14 by which the pressure of the pressure oil is boosted. Since the conditions for packing the molten metal are stabilized, the generation of a defect in the product is prevented.
|
