| 摘要 |
PURPOSE:To control ascending and descending of a cylinder ram with good responsiveness by incorporating a spool into a cylinder ram, and shortening the length of an oil piping to a cylinder tube. CONSTITUTION:When an ascending command is emitted to a cylinder ram 1, a rod 21 of a servocontrol actuator 20 is moved upward by the oil directional control of a pilot valve 24 and a spool 5 connected to the rod 21 ascends in a sleeve 4. More specifically, an inlet port 10 and the 1st port 13 are communicated through the 2nd valve chamber 8 and the 2nd port 14 and the 1st outlet port 11 are communicated through the 3rd valve chamber 9. The oil is therefore supplied from a hyraulic pump P to the lower position of the ram 1 in a cylinder tube 2 and the oil is discharged from the upper position of the ram 1 into a tank T, then the ram 1 ascends. The ram 1 ascends in follow-up to the spool 5 and when the spool 5 is stopped by the control system of the actuator 20, the ram 1 is held in accordance with said stop position so that the required ascending position of the ram 1 is maintained. |
