| 摘要 |
PROBLEM TO BE SOLVED: To prevent an audible sound from being generated by magnetically shielding a coil so that magnetic induction to each oscillation circuit due to a magnetic noise being generated from the coil that is provided at each voltage- generating circuit can be suppressed. SOLUTION: When ultrasonic motors 10 and 70 are driven simultaneously, coil of a voltage-generating circuit of the ultrasonic motor 10 and that of a voltage-generating circuit of the ultrasonic motor 70 may generate a magnetic noise. However, the magnetic noise is absorbed by permaloy for magnetically shielding the coils, thus preventing the magnetic noise from being magnetically induced to oscillation circuits 34 and 64, hence stabilizing an oscillation frequency and preventing an audible sound from being generated. |
