Electro-mechanicalsignal converter, in which an electromagnetic armature moves in the magnetic field of two permanent magnets (Figure T 14). If one side is activated, the magnet rotates in this field, which is transferred to a flexible spring (flexible tube) that is firmly connected to the armature. The deflection of the armature is active until a balance is established between the magnetic force and the spring force. At the same time, this rotary movement is transferred to the flapper of an flapper-nozzle system, where it generates differential pressure.
Thanks to the low mass, the dynamic performance of the torque motor is very good, meaning that it is also suitable for high demands in terms of time response. The torque motor is primarily used in the piloting stage of servo valves.
Figure T 14: Torque motor