| 摘要 |
PROBLEM TO BE SOLVED: To enhance the stability and the responsibility of both the speed control and pressure control to meet the requirement of speed-up and precision improvement (higher quality) for injection molding and, at the same time, to simplify the structure of the hydraulic circuit and to reduce the cost. SOLUTION: In composing the apparatus that drives the injection cylinder 3 by connecting A port and B port of the four-port servo valve to the cylinder rear chamber 3r and the cylinder front chamber 3f of the injection cylinder 3 respectively and connecting the hydraulic driving source 5 and the oil tank 6 to P port and T port of the four-port servo valve respectively, there is equipped with the four-port servo valve 4 which connects the injection cylinder 3 having the built-in single rod type piston 3p with at least the cylinder rear chamber 3r and the hydraulic driving source 5, which also connects the cylinder front chamber 3f with the oil tank 6, and which in addition has the first position Xa that turns down the quantity of the flow of the return oil Op of the meter-out side 3fo in correspondence with the ratio of the pressure areas of the cylinder front chamber 3f and the cylinder rear chamber 3r. COPYRIGHT: (C)2009,JPO&INPIT
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