Design and Research of Cavity Resonant Type of Pneumatic Vibrator

超音波輔助鑽削經證實可以有效提升高硬度材料的切削效率。高頻振動能夠容易地以電能實現，但在牙醫手機潮濕使用環境會有漏電的安全疑慮。本論文目的在於設計開發軸向氣壓振動器整合於現有的微型氣渦輪筒匣，以高壓空氣為動力源來產生高頻率的軸向振動。 由於低能源消耗，自激式振動原理被選用來進行氣壓振動器的設計開發，激振源引用空腔共振現象，並利用壓力釋放與回復機制將氣體壓力能不間斷的轉換為振動動能。設計流程首先透過理論探討研究氣壓振動器的原理與影響因素，再依據開發得的實體設計模型，執行流場動態模擬(CFD)以深入瞭解最佳化設計參數與振動性能之間的關係。依據最佳化結果，一些雛型氣壓振動器被精密地開發出來。透過實驗測試，驗證負載對雛型氣壓振動器性能 - 振幅與頻率 - 之影響。最後透過氣壓振動器和微型氣渦輪筒匣的整合測試，證實了超音波輔助鑽削的性能。 實驗結果驗證了空腔共振式氣壓振動器的可行性，在無軸向負載的情況下，供氣壓力5.5 bar時，振動頻率最高可達674 Hz，振幅為91 μm。在軸向負載情況和供氣壓力4 bar時，氣壓振動器可以承受最大負載達2035 mN，振動頻率為535 Hz，振幅為93 μm。500 mN徑向負載下的氣渦輪筒匣可以透過氣壓振動器的輔助，在頻率341 Hz的軸向振動下有效提升切削率達2.5倍。The ultrasonic assisted drilling has been verified to be able to significantly improve the cutting efficiency of high hard materials. High-frequency vibrations can be easily realized by electric power. But there are some security concerns such as electrical leakage in humid environment for application of dental handpiece. The aim of this thesis is to develop a pneumatic axial vibrator integrated with the existing air turbine cartridge. High pressure air is applied as the power source to create high frequency axial vibration. Because of less power consumption, the self-excited vibration is chosen as the working principle of the developed pneumatic vibrator, and its excitation source draws on the cavity resonance phenomenon. The pressure relief and recovery mechanism is designed to continuously convert the gas pressure into the kinetic energy of vibration. Firstly through the theoretical analysis, the working principle and the influential parameters of the pneumatic vibrator are studied and evaluated. According to its derived embodiment design, the CFD simulation is carried out to comprehend and optimize the relationship between the design parameters and the vibration performance. Based on the optimized result, the prototypes are precisely developed. The developed prototypes are experimentally tested to verify the influence of load on their performance - vibration amplitude and frequency. Finally through the integration testing of the pneumatic vibrator and the air turbine cartridge, the ultrasonic assisted drilling performance is also confirmed. The experimental results demonstrate that the cavity resonance effect is feasible to drive the pneumatic vibrator. Without axial load, the pneumatic vibrator can create an amplitude of 91 μm at the frequency of 674 Hz for the air pressure of 5.5 bar; and it can withstand a maximum load of 2035 mN by supplying an air pressure of 4 bar and achieve an amplitude of 93 μm at the frequency of 535Hz. The air turbine cartridge under a radial load of 500 mN can be assisted by the pneumatic vibrator to effectively enhance its cutting rate by 2.5 times that without axial vibration at the frequency of 341 Hz.口試委員會審定書 i 誌謝 ii 中文摘要 iii Abstract iv 目錄 v 圖目錄 vii 符號表 ix 第一章 緒論 1 1.1 研究背景與動機 1 1.2 文獻回顧 3 1.2.1 超音波輔助鑽削 3 1.2.2 牙醫用微型氣渦輪筒匣 4 1.2.3 氣壓振動器 4 1.3 研究目標與章節內容摘要 10 第二章 空腔共振式氣壓振動器之原理與理論分析 11 2.1 空腔共振式氣壓振動器系統組成 11 2.2 自激式振動 12 2.2.1 原理 12 2.2.2 理論分析 15 2.3 空腔共振現象 23 2.3.1 Hartmann笛的運作原理 24 2.3.2 Hartmann笛的理論分析 27 2.4 壓力釋放與回復機制 30 2.4.1 原理 30 2.4.2 理論分析 36 第三章 空腔共振式氣壓振動器之實體設計 39 3.1 振動器整體架構 39 3.2 空腔共振激發源 42 3.3 排氣閥常關機制 43 3.4 流場模擬分析 46 3.4.1 自激式振動 46 3.4.2 壓力釋放與回復機制 51 3.5 微型氣渦輪筒匣整合空腔共振式氣壓振動器 56 第四章 微型氣渦輪筒匣整合空腔共振式氣壓振動器之性能量測 58 4.1 軸向振動頻率與振幅量測 58 4.2 軸向承載力量測 69 4.3 切削能力量測 72 第五章 結論與未來展望 74 參考文獻 76 附錄A 霍爾效應感測器（3503） 79 附錄B 荷重元（LVS-2kA） 81 附錄C 訊號放大器（DPM-712B） 82 附錄D 資料擷取卡（NI-6008） 8