FREQUENCY TRACING CONTROL METHOD FOR ULTRASONIC VIBRATOR TRANSDUCER

摘要

PURPOSE:To allow the always stable detection of the natural frequency of an ultrasonic vibrator transducer by superposing and building a piezoelectric element for generating vibrations and a piezoelectric element for picking up vibrations into a bolted Lengevin type ultrasonic vibrator transducer, thereby constituting the integral ultrasonic vibrator transducer. CONSTITUTION:The piezoelectric element 2 for generating vibrations and the piezoelectric element 10 for picking up vibrations are superposed and built into the bolted Lengevin type ultrasonic vibrator transducer 1. The ultrasonic vibrator transducer 1 is vibrated by impressing the the high-frequency voltage from a self-oscillation control circuit 5 to the piezoelectric element 2 for generating vibrations. Further, the voltage generated by the vibration of the piezoelectric element 10 for picking up vibrations is fed back via a frequency-to-voltage conversion circuit 11 to the self- oscillation control circuit 5 and is used as the frequency source of the self-oscillation control circuit 5. Consequently, the vibrations of the ultrasonic vibrator transducer 1 are exactly detected and are fed back to the circuit 5 which traces the natural frequency according to a change in the physical constant of a horn 3, test piece 4, etc., so as to vibrate the vibrating transducer 1 always at the adequate natural frequency.