Effect of tightening torque on the frequency of the sandwich piezoelectric ceramic transducer vibrator

In the piezoelectric transducer vibrator assembly process, the pre-stress plays important influence on the resonance frequency of transducer vibrator. The effect of tightening torque on the resonance frequency and the impedance of the piezoelectric ultrasonic transducer vibrator during assembly process is studied in this paper. The relationships between resonance frequency, impedance and tightening torque are measured by experiments. As the tightening torque increased from 50 to 110 kgf.cm, the resonance frequency increased exponentially from 51.7 to 54.6 KHz while the impedance decreased exponentially from 12.1 to 5.8 Ohm. When the tightening torque was larger than 65 kgf.cm, the resonance frequency of transducer vibrator had little change. Experiments studied that the resonance frequency of transducer vibrator can be controlled by tightening torque in assembly process, to obtain better conformity of quality of transducer.