| 摘要 |
PURPOSE:To reduce the pressure loss of supplying oil pressure for driving injection screw as much as possible by a method wherein the set pressure of a solenoid pressure control valve is set by the flowing pressure in an injection cylinder under advancing added with a predetermined plus pressure. CONSTITUTION:A servo flow amount control valve 14, controlling an injection speed by choking the flow amount, is provided between a pipeline 10 and the inlet side pipeline 13 of the injection cylinder 3 while the solenoid pressure control valve 15 is provided in the primary side pipeline of the servo flow amount control valve 14 or the side path of the pipeline 10. A pressure sensor 16, detecting the flowing pressure in the injection cylinder 3 under advancing for injection, is attached to the secondary side pipeline of the servo flow amount control valve 14 or the pipeline 13. The set pressure of the solenoid pressure control valve 15 is set by the flowing pressure P1 in the injection cylinder 3, which is detected by the pressure sensor 16, added with the value of pressure of plus (alpha), whereby the pressure loss (shaded portion B in the diagram) or the difference between the maximum value Pa(Pa=Pf+alpha) of flowing pressure as the supplying oil pressure and the actual flowing pressure driving an injection screw may be reduced. |
