P5E-1 Motion Analysis of the Surface Particle of a Coiled Waveguide Due to the Flexural Wave

A traveling-wave-type miniature ultrasonic motor has been developed using a helical coiled waveguide as a stator, and it has been applied to an IVUS probe. In this motor, the elliptical motion of the surface particle due to the flexural ultrasonic waves rotates the rotor, which can be placed adjacently inside or outside the stator, via the frictional force. However, the fact that the rotational direction of the outer rotor is reverse to that of the inner rotor at low frequencies of the flexural wave cannot be explained theoretically. In this study, the above surface particle motion is investigated through FEM simulations, and the principle of the above-mentioned rotational direction is clarified.