D761series.pdfVIP

Servovalves D761 Series ISO 10372 Size 04 2D761 Series Two stage servovalves Operational features r 2-stage design with dry torque motor r Low friction double nozzle pilot stage r High spool control forces r Mechanical feedback r Internal or external pilot supply optional r Protection filter easy to replace Q [l/min] = max. flow Dp [bar] = valve pressure drop with Q A K [cm 2 ] = spool drive area p X [bar] = pilot pressure The pilot pressure p X has to be at least 15 bar above the return pressure of the pilot stage. Q Q p p N N = ? ? The actual flow depends on the electric command signal and the valve pressure drop, and may be calculated using the square root function for a sharp-edged orifice. Q [l/min] = calculated flow Q N [l/min] = rated flow Dp [bar] = actual valve pressure drop Dp N [bar] = rated valve pressure drop p 2,5 10 Q A p X -2 K ≥ ? ? ? Our quality management system is certified in accordance with DIN EN ISO 9001. If large flow rates with high valve pressure drops are required, an appropriate higher pilot pressure has to be chosen to overcome the flow forces. An approximate value can be calculated as follows: The D761 Series servovalves are throttle valves for 3- and preferably 4-way applications. According to the requirements of the appli- cation, the user can select either the standard version (S) or the high response version (H). The main feature of the high response valves is improved dynamics. These valves are suitable for electrohydraulic position, speed, pressure or force control systems with high dynamic response requirements. Description The servovalves D761 Series consist of an electromechanical trans- former (torque motor), a hydraulic amplifier (nozzle/flapper principle), a spool in a bushing and a cantilever feedback spring. The torque motor contains coils, pole pieces, permanent magnets and an armature. The armature is connected to a flexible tube which allows a limited rotation of the armature and at the same time seals the electro