PURPOSE: To provide an ultrasonic motor which is always stable in operation and efficient and capable of downsizing by reducing the number of protrusions, taking the position of the installed protrusion into consideration, so that it may not affect the vibration of a vibrator, in an ultrasonic motor of such constitution that many protrusions are made at the elastic board constituting the vibrator.
CONSTITUTION: Protrusions are provided, at nearly equal intervals in circumferential direction at a rate of one pierce per progressive wave, at the contact face with a mover 13 of an elastic board 10. The position of the protrusion lies nearly halfway between the node A1 of one hand and the node B1 of the other hand out of two standing waves constituting the progressive waves. The position of the first protrusion may be nearly halfway between the node A2 of one hand and the node B1 of the other hand out of two standing waves constituting the progressive waves, or nearly halfway between the node A2 of one hand and the node B2 of the other hand between the two standing waves, or nearly halfway between the node A3 of one hand and the node B2 of the other hand out of two standing waves, and after that, they may be provided at a rate of one per wave.
SUMIHARA MASANORI
NOJIMA TAKASHI
NISHIKURA TAKAHIRO
TAKEDA KATSU
IMADA KATSUMI
