| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem in which a speed is reduced when there is a difference in the maximum amplitudes of two natural vibration modes used for driving of an ultrasonic motor and resonance frequencies of the two natural vibration modes substantially match each other.SOLUTION: In an ultrasonic motor which includes a diaphragm having a rectangular flat plate part and a protrusion part provided on the flat plate part, a piezoelectric element fixed on the diaphragm and performing high frequency vibration, a friction member brought into contact with the protrusion part and a first natural vibration mode and second natural vibration mode excited to the diaphragm by high frequency vibration, and in which the diaphragm and the friction member relatively move, the maximum amplitude generated on the tip of the protrusion part with the first natural vibration mode is larger than the maximum amplitude generated on the tip of the protrusion part with the second natural vibration mode, a resonance frequency of the first natural vibration mode is lower than a resonance frequency of the second natural vibration mode, and the amplitudes of the first natural vibration mode and the second natural vibration mode of the frequency band at the time of driving substantially match each other.SELECTED DRAWING: Figure 4 |
