高速氣動鑽具整合套杯式動靜壓混合氣壓軸承之設計開發與性能探究

Design and Research of Pneumatic Drilling System Integrated with Cap-shaped Hybrid Aero Bearing

汪君叡(Chun-Jui Wang)

指導教授 ： 黃光裕

國立臺灣大學/工學院/機械工程學研究所/碩士(2012年)

https://doi.org/10.6342/NTU.2012.02346

摘要

隨著3C電子產品的成長，高速PCB鑽孔機需求量大增；而傳統PCB鑽孔機以電磁馬達驅動方式易發熱及轉速較低問題，本研究提出以氣渦輪轉子作為旋轉動力源，取代傳統電磁馬達。氣渦輪轉子具有極高轉速、結構簡單及自散熱等優點，應用於PCB鑽孔機可改善鑽具之切削性能。高性能軸承可使鑽孔機主軸有較好的旋轉性能及穩定性，並具有自散熱、無磨損、低噪音等特性，本研究以氣靜壓軸承輔以氣動壓軸承提供氣渦輪轉子穩定支撐，這混合式軸承被設計成套杯式形狀來穩定氣膜壓力以提升旋轉穩定性。
本研究以理論推導分析氣渦輪及氣壓軸承之性能趨勢，並配合CFD流場分析軟體模擬氣壓軸承流場分佈情形，以瞭解機能和最佳化設計參數。依據分析結果完成氣動鑽具系統整合套杯式混合氣壓軸承設計，軸承採用替換式套筒模組，以利於設計方案的測試驗證。鑽具系統的動力、承載力、切削性能等也透過實驗進行量測。透過理論分析和實驗結果的相互比較，進行誤差分析並推演出可行的改良方案。
整合混合式氣壓軸承之高速氣渦輪鑽具系統在供氣壓力為2 bar時，轉速可達6388 rpm，最大扭力約為37.38 N∙mm；透過動靜混合式氣壓軸承，徑向承載力可達1.65 N，鑽具軸向承載力可達5.13 N，標準PCB板可於9秒內鑽穿，尺寸誤差約為4 % ，真圓度達46 um。

關鍵字

PCB鑽孔機 ； 氣渦輪轉子 ； 套杯式 ； 氣靜壓軸承 ； 氣動壓軸承 ； 混合氣壓軸承

並列摘要

Because of progressive development of 3C products, the demand of high-speed PCB drilling machine tools is rapidly increasing. However, traditional drilling machines driven by electromagnetic motors always involve some drawbacks such as resistive heating and low-speed limitation. Instead of electromagnetic motor, this thesis proposes the concept of air turbine for developing a novel drilling tool. With the advantages of high-speed, simple construction, and self-cooling, the application of air turbine can improve the performance of PCB drilling machine tools. High-performance bearing can further enhance the rotation performance and stability of drilling shaft, and it also possesses the characteristics of self-cooling, no-wear, and low-noise. In this thesis the aerostatic bearing assisted by an aerodynamics bearing is developed to support the rotor of the air turbine, and this hybrid aero bearing is designed in a cap-shaped form to stabilize the air-gap pressure in order to increase the rotational stability.
Through the theoretical analysis, the performances of air turbine the aero bearing are separately analyzed. And the CFD software is also used to simulate the pressure and stream distribution inside the aero bearing in order to comprehend functionality and to derive optimized design parameters. Based on the analytical results, the pneumatic drilling system is integrated with the cap-shaped hybrid aero bearing, which is built up with changeable modular construction. Its power, capacity, and cutting performance are experimentally verified. Through the comparison between the analytical and experimental results, the error analyses are carried out and the improvement proposals are derived.
The drilling system achieves a maximum rotational speed of 6388 rpm and a maximum torque of 37.38 N∙mm under the supply pressure of 2 bar. Through supporting by the cap-shaped hybrid aero bearing, its axial and radial loading capacities are 5.13 N and 1.65 N, respectively. The standard PCB-board can be drilled through in 9 s, and its diametrical error is smaller than 4%, and its roundness 46 um.

並列關鍵字

PCB drilling machine ； Air turbine ； Cap-shaped ； Aerostatic bearing ； Aerodynamics bearing ； Hybrid aero bearing

參考文獻

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