| 摘要 |
<p>PURPOSE:To provide the titled inexpensive controller possessing a long service life and an improved reliability, obtained by constituting so as to carry out a closed loop control by combining a solenoid valve and a check valve, and by providing a blind sector within the control loop. CONSTITUTION:When the signal is given by the controller 24 to the solenoid valves 9, 10, the pressurized oil delivered from the pump 11 flows into the cylinders 14, 15, through the solenoid valves 9, 10, and the pilot check valves 12, 13, so that the upper and the lower intermediate rolls 4, 5, are displaced by distances X1, X2, in respect of the reference length L. These distances of displacement are detected by the selsyn signal generators 16, 17, whose signals are sent to the controller 24 as the feedback; at the end of displacement, the oil path is closed, so that the cylinders 14, 15, are held at their present positions. A blind sector of specified plus an minus widths from the reference middle point, is provided within the above-mentioned controller 24; if the deviation of the roll position due to an oil leak of the pilot check valves 12, 13, is in the range of the blind sector, the positions of cylinders 14, 15, are held by only the check valves 12, 13; if the deviation extends out of the blind sector, the closed loop control is established, and the roll position is corrected by operating the solenoid valves 9, 10.</p> |
