| 摘要 |
PROBLEM TO BE SOLVED: To smoothly perform control of the speed in lowering and stopping of a hydraulic elevator to be driven by a normal inverter motor, so as to comfortably stop the elevator. SOLUTION: A controller for a hydraulic elevator has a structure for feeding operating oil discharged from a hydraulic pump 1 to a hydraulic cylinder 10, raising a hydraulic elevator, opening a pilot check valve 7 by a lowering command, allowing the operating oil in the hydraulic cylinder 10 in the opposite direction to that in raising, and lowering the hydraulic elevator while reversely rotating the hydraulic pump 1. In a valve opening mechanism for the pilot check valve 7, to be used in lowering, pressure in the cylinder 10 is used as pilot pressure, the valve opening amount of a main valve is increased by turning on a high-speed solenoid valve 23 from the time that lowering is started to the time just before lowering is stopped after the speed reaches the lowering speed, high-speed lowering is performed, and a speed change in starting of lowering and in stopping of lowering is made smoother in combination with rotational speed control of the hydraulic pump 1 by frequency control of an inverter motor 2. |
