Big machine tools and universal milling-boring machines are equipped with specific electrohydraulic systems to counterbalance the weight of the saddle and spindle during the vertical displacements, thus permitting the electromechanical driving unit to perform smooth and accurate motion controls.
Two different hydraulic solutions are commonly used for the counterbalance function: active circuit with power unit or closed circuit with accumulators.
In active solution, the 3-ways high performance pressure reducing valves with on board digital electronics perform an accurate closed loop pressure control in the counterbalance
hydraulic cylinders thanks to the built-in pressure transducer installed on valve pressure ports.