Tomoaki Mashimo of Toyohashi University of Technology developed a one cubic millimeter ultra-small ultrasonic motor. The newly developed ultrasonic motor, whose sides are 1 mm each, is smaller than one fortieth of the smallest ultrasound motor in volume, and it allows for rotation movement and translatory movement. It is designed to be built on to a catheter for the examination and treatment of cerebrovascular disease. The professor will improve the performance and conduct clinical testing to put it into practical use in three years.
He successfully miniaturized the structure of the motor by creating lots of small holes in the metal part called stator that covers the driving part for easier transmission of power. The piezoelectric element is stuck to the periphery of the stator made of gold base alloy. The new motor is 1.5 mm wide including the piezoelectric element. Because the structure is simple, the production cost will not be high. When two kinds of alternating currents are applied to the piezoelectric element, they elongate and contract it. The telescopic motion is converted to the vibration of the motor, and the vibration generates power. The motion and strength of the motor can be controlled by modifying the way to apply voltage.
A sample of ultrasonic motor. The newly-developed ultra-small ultrasonic motor developed by a professor of Toyohashi University of Technology is just one cubic millimeter.