| 摘要 |
An ultrasonic stepping motor which can be driven stepwisely by use of vibration of an ultrasonic wave. The ultrasonic stepping motor has a stator (105, 303, 503) which switches over a plurality of vibratory states in a time series manner, and a rotor (107, 302, 502) which is in contact with the stator (105, 303, 503) so as to be driven by frictional force. The vibratory states of the stator (105, 303, 503) include at least a composite vibration, i.e., a progressive wave (c), formed from two standing wave vibrations, and a standing wave (a) vibration state. The stator (105, 303, 503) is provided with relief portions (51, 51a) at respective positions corresponding to the antinodes of a standing wave vibration, the stator (105, 303, 503) being in contact with the rotor (107, 302, 502) at positions (107a) corresponding to the nodes of the vibration. <IMAGE> |
