Miniature gear reduction unit driven by a silicon electrostatic wobble motor

This work illustrates and explores one possibility to link watch fine mechanics to silicon-based actuators. A small scale microreduction module, a pinion-gear train, coupled to an electrostatic wobble motor (calculated power figure about 1 μW), is described. The motor parts are fabricated on silicon. Electrodeposition of nickel in a positive photoresist mould is used for the fabrication of the rotor (φ 2 mm). This last is flexible to permit vertically- wobbling and is directly connected to an output shaft. Functional operation of this microreduction unit was successful and demonstrated the possibility to output torque from an electrostatic wobble motor. Measurements and observations of rotor elasticity and gears/axle characteristics:are presented and discussed in view of a possibly improved design