| 摘要 |
PURPOSE:To provide an ultrasonic motor drive device which drives a driving body brought into contact with a piezoelectric vibrator. CONSTITUTION:A phase deciding circuit 7 divides the output of an oscillator 6 into four phases after dividing the frequency of the output into halves and inputs the four-phase outputs to a switching circuit 8 connected with a change- over switch 9 which changes the direction of progressive waves. The output of the circuit 8 is inputted to a drive circuit 10 and the four outputs of the circuit 10 are connected to four electrodes 12a, 12b, 12c, and 12d equally provided on one surface of a piezoelectric vibrator 11. At the same time, the outputs of the circuit 10 are also respectively connected to electrodes 13a, 13b, 13c, and 13d which are equally provided on the other surface of the vibrator 11 by shifting the connecting order of the electrodes by one to 13b, 13c, 13d, and 13a and an adder 14 takes the sum of two of the four outputs of the circuit 10. The sum is amplified by means of an amplifier 15 and positively fed back to the oscillator 6. Therefore, the vibrator 11 can generate stable progressive waves and a driving body press-contacted with the vibrator 11 can be smoothly rotated. |
