| 摘要 |
PURPOSE:To reduce die closing time and to open and close dies smoothly by providig check valves in the bypassing passages on the discharge side of pistons, and controlling the die closing operation of cylinders by shutting off the passages thereby controlling die opening and closing speeds effectively. CONSTITUTION:A flow rate control valve 11 is moved to the left from a neutral position A, and lines 12, 13 and lines 16, 17 are connected in a position B. The pressure oil from a pump 15 is supplied through the valuve 11 to the line 12 to move a piston 8b downward. The die closing is accomplished smoothly by comparing the speed set with a setter 20 and the speed detected with a detector 19 which measures the moving position of the piston 8b and operating the valve 11 by the results of said comparison. As the piston 8b moves downward, the oil on the lower side flows through the line 13 and is blocked by a check valve 25 so that is goes through a bypass line 27 and a check valve 28 and joins to the line 16. Further, its backflow to the pump side is blocked by a check valve 24, and the oil is supplied onto the piston 8b through the lines 16, 12. Thereby, the die closing is accomplished quickly. Since the speed is decelerated at the time of die registering, the dies are closed smoothly without any damage. |
