A small, linear, piezoelectric ultrasonic cryomotor

摘要

A small, linear-type, piezoelectric ultrasonic cryomotor has been developed for precision positioning at extremely low temperatures (≥-200℃). This cryomotor consists of a pair of Pb(Mg_(1/3)Nb_(2/3))O_3-PbTiO_3 single crystal stacks, which are piezoelectrically excited into the rotating third-bending mode of the cryomotor stator's center, which in turn drives a contacted slider into linear motion via frictional forces. The performance characteristics achieved by the cryomotor are: (ⅰ) a maximum linear speed of > 50 mm/s; (ⅱ) a stroke of > 10 mm; (ⅲ) a driving force of > 0.2 N; (ⅳ) a response time of ～29 ms; and (ⅴ) a step resolution of ～20 nm.