Design and Research of a Miniature Pneumatic Vibrator

傳統高頻振動器多使用壓電效應或磁變形效應的原理。電氣式振動器的熱效應一直是為人詬病的特性。本論文利用氣體自我降溫的特點，以氣體軸承氣壓致振的原理，開發設計小型、高功率輸出、高效率的高頻振動器。設計上使用兩個對向配置的軸向氣體軸承，將其間的致動件來回推擠，利用微小氣膜間隙下氣體可壓縮性所產生的不穩定現象，使致動件產生振動的效果。性能分析透過理論計算與有限元素模擬，對承載力、剛性與激振頻率作出預測；實驗則包含無負載、負載特性的量測，最後透過振動影響參數質量和彈簧負載的調整，提出具體設計改良。實驗成果驗證了氣鎚現象作為氣壓式振動器原理的可行性，系統為一直徑30mm、高31mm 之圓柱體結構，測試頻率最高為5.4kHz，供氣壓力4bar 時質量負載可達1kg，最高有65%的能量轉換效率和66W 的功率輸出，經由設計改良，振動器的性能可獲得進一步的提升。Most conventional high-frequency vibrators generate the working power basedn the piezoelectric and magnetostrictive effects. After entering the transducingystem, the input time-varying electric energy will then be transferred into solid-bodyibration; however, the heat dissipated has always been a critical issue of suchibrators. Therefore, the objective of this research was to develop a miniatureigh-frequency vibrator with high power output and high energy efficiency, whichook advantage of the self-cooling property of gas and the pneumatic instability torigger the vibration motion. Two aerostatic bearings were placed in the oppositeonfiguration with the driven part oscillating back and forth due to the pneumaticammer phenomenon. Full analysis was done by both theoretical calculation andinite element method. Predictions of load capacity, equivalent stiffness, and excitedibrating frequency were all proved possible and applicable while measurements ofhe unloading and loading characteristics of the vibrator were carried out byxperiments. Besides, parameters including driven mass and spring loading effectere examined to a thorough understanding. In the end, modifications for theesigned vibrator were proposed to acquire better system performance.口試審定書……………………………………………………………………...……..I謝............................................................................................................................... I文摘要......................................................................................................................III文摘要......................................................................................................................IV目錄........................................................................................................................ VII目錄..........................................................................................................................XI號表........................................................................................................................ XII一章. 緒論............................................................................................................1.1. 研究動機與背景........................................................................................1.2. 文獻回顧....................................................................................................2.2.1. 壓電式振動器................................................................................3.2.2. 磁變形振動器................................................................................4.2.3. 其他電氣式振動器........................................................................5.2.4. 氣壓式和液壓式振動器................................................................5.2.5. 高頻振動器之性能指標..............................................................10.3. 研究目標與內容簡介..............................................................................11二章. 氣致振動原理..........................................................................................12.1. 氣鎚現象..................................................................................................12.2. 氣鎚振動之理論分析..............................................................................14.3. 氣鎚振動器之設計要求..........................................................................18三章. 對向式氣鎚振動器之設計開發..............................................................19.1. 氣鎚振動器之負載能力與剛性..............................................................19.2. 氣鎚振動之激發條件..............................................................................23.3 節流器尺寸的影響探討..........................................................................30.4 對向式氣鎚振動器之實體化設計..........................................................34.3.3 實驗化設計..........................................................36四章. 系統性能檢測..........................................................................................41.1 無負載特性量測......................................................................................41.2 負載特性..................................................................................................52.3 振動影響參數之探討..............................................................................54.3.1 致動質量效應探討......................................................................54.3.2 彈簧負載效應探討......................................................................56.3.3 對向式氣鎚振動器之設計改良..................................................60五章. 結論與未來展望......................................................................................64amp;#63851;考文獻......................................................................................................................66錄A 流量計特性規格(GFM 37) .......................................................................69錄B 光纖位移計特性規格(MTI 2100).............................................................71錄C 美商國家儀器PXI 訊號處理器(PXI-1002).............................................73錄D Tektronix 多功能示波器(TDS 2002 B) ....................................................7