Transducer for high speed and large thrust ultrasonic linear motorusing two sandwich-type vibrators

摘要

A transducer for an ultrasonic motor using two sandwich-typenvibrators has been proposed and designed. The vibrators cross at rightnangles with each other at the tip. The transducer has two vibrationnmodes; one is a symmetrical mode and the other is anti-symmetric. Thennormal direction motion of the transducer tip is excited by thensymmetrical mode. The lateral motion of the tip is excited by thenanti-symmetrical mode. The transducer is designed so that thesenvibration modes are degenerated. To obtain high output force and highnpower, materials were carefully selected. Heat-treated high strengthnchromium manganese steel bolts were used for binding the PZT elements. Anzirconia ceramics plate was bonded on the transducer tip as frictionalnmaterial. The no-load maximum speed was 3.5 m/sec. The output force wasn39 N at the driving voltage of 500 Vrms and the preload ofn150 N. At this condition the maximum efficiency was 28%, and thenvelocity was 0.55 m/sec. The maximum output force was 51 N, which was 17ntimes of the transducer weight. The maximum output power per unit weightnwas 76 W/kg