人工喉頭におけるPZT圧電振動体設計および音響特性評価

摘要

The available piezoelectric vibration body in the artificial larynx has a vibration board in a frame. Therefore, the existing piezoelectric vibration body has oscillated at higher frequency than voice fundamental frequency. Moreover, it was unable to predict the sound pressure, because amplitude and area of the vibration board were small. Hence, we designed a new piezoelectric vibration body for the purpose to increase in vibration board amplitude and reduction of the oscillatory frequency. The designed piezoelectric vibration bodies consist of frame and vibration board which was supported by a diagonal beam. An actuator （PZT） is located on the both sides of the diagonal beam. PZT expands and contracts by adding AC voltage, it makes the vibration board vibrate. However, to know about the best dimensions of the beam and vibration board experimental design and piezoelectric analysis was performed. Furthermore, we have carried out dynamic analysis to evaluate the acoustic properties in the best condition model because acoustic properties of the resonance were unclear by the statics analysis. We have also confirmed frequency response characteristics and sound pressure distribution from dynamic analysis. From the analysis results, we confirmed that best condition model has low directional characteristics and it oscillated higher frequency than voice fundamental frequency. Moreover, we also confirmed that the sound pressure level is smaller than sound pressure of the human conversation.