Noncontact rotary motors driven by surface acoustic waves

On the basis of the research of friction-driven rotary motors,a kind of noncontact rotary motors driven by surface acoustic waves(SAWs) is fabricated.In the prototype of the motor,two surface acoustic waves propagating in the antiparallel directions are introduced on the stator,which are excited by two pairs of interdigital transducers(IDTs) on the 128°YX-LiNbO₃ substrate.A liquid layer is loaded on the stator,and the rotor is suspended on the surface of the liquid.Two antiparallel acoustic streaming flows are produced by both acoustic waves in the liquid.The motion of the viscous liquid finally drives the rotor to move.Some preliminary experimental results,such as the variation of the angular velocity of the noncontact motors with the driving voltage of the IDTs,the thickness of the liquid layer and the viscosity of the liquids,are presented.It is also found that,with the same operating frequency,the threshold of the driving voltage of the noncontcat rotary motor is much smaller than that of the friction-driven ones.