| 摘要 |
PURPOSE:To control injection speed far correctly, by a method wherein a side path is connected with a pipe path between a directional control valve and a flow control valve, an oil tank is connected with the side path and a solenoid valve for a brake closing at the time of a forward movement of a screw is provided on the side path. CONSTITUTION:At the time of high-speed injection, a solenoid valve 13 for a brake is not excited and oil flows freely through the solenoid valve 13 for the brake. Hydraulic pressure is fed to one side cylinder chamber 3a of a cylinder 2, and the oil is discharged through the other cylinder chamber 36 into an oil tank 9 without meeting with any resistance, therefore, a screw 1 moves forward at a high speed. When injection of raw material resin is completed through a forward movement of the screw 1, an injection speed of the screw 1 is changed over to a low speed due to dwell, however, at the time of the changeover the solenoid valve 13 for the brake is excited and closed. Therefore, as the oil comes out of the left side cylinder chamber 36 of the cylinder 2 does not pass through a side path 12, and squeezed by passing through a flow control valve 8 in the direction of electromagnetic force, a forward movement of the screw 1 is met with resistance and the injection speed is changed over to low speed.
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