METHOD AND MECHANISM FOR DRIVING SCREW ROD BY ULTRASONIC VIBRATION

摘要

PROBLEM TO BE SOLVED: To automatically adjust a screw rod without play by integrally forming a vibrator and a piezoelectric actuator, and applying a constant pressure to the circumference of the screw rod from the vibrator and a clockwise or counterclockwise rotating voltage across the right or left side of the vibrator. ;SOLUTION: A screw rod 2 is mounted on screw rod pedestals 3 and 3 via bearing 4 and 4, and a piezoelectric actuator 6 with vibrator is integrally formed with a vibrator pedestal 5. Then springs 8 are set by compressing the springs 8 by means of spring clamping locking tools 9. Consequently, the vibrators of the actuator 6 always give large friction to the circumference of the rod 2 by pressing the rod 2 with constant pressures. When a voltage is applied across the vibrators 7 (a) and 7(d) therefore, the actuator 6 rotates counterclockwise, and when a voltage is applied across vibrators 7(b) and 7(c) conversely, the actuator 6 rotates clockwise and the vibrator pedestal 5 moves on rails 11. Accordingly, no play nor backlash occurs, even if frictional sections of the vibrators are slightly worn.;COPYRIGHT: (C)1999,JPO