Control device for hydraulically operated valve e.g. proportional directional control valve

摘要

The control device uses a pair of pre-control valves (11,12), provided as pressure reduction valves and used for movement of the main valve in the same direction from its rest position upon individual operation. One of the pre-control valves (12) has a greater maximum output pressure than the other and is operated for reducing the pre-control pressure in the control pressure space (21) of the main valve to a value below the output pressure of the operated pre-control valve.