止推氣靜壓軸承之磁變形致動節流裝置之設計與開發與性能測試分析

Design and Development of a Magnetostrictive Actuating Restrictor for Aerostatic Thrust Bearing and Performance Analyses

蕭宇均(Yu-Chun Shiao)

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(2006年)

https://doi.org/10.6342/NTU.2006.00592

摘要

科技發展趨勢引導下，氣壓軸承因為低運轉摩擦以及高運轉精度等性能表現，愈來愈受到重視，其中節流裝置又是提升氣體靜壓軸承剛性與穩定性之關鍵元件，藉由流量調節功能可以使氣膜壓力得以穩定；提昇氣壓軸承剛性進一步可以增加轉軸運轉精度。本論文的研究目的在於設計開發一種具有主動補償式節流裝置之氣靜壓軸承系統，並且從設計和運轉參數探討軸承負載補償能力之影響。主動補償式節流裝置採用狹縫節流形式，首先透過理論分析模型與流場有限元素等分析方式來分析探討節流狹縫對氣靜壓軸承承載能力之影響。節流狹縫之調節致動則以磁變形材料Terfenol-D之巨大磁變形效應作為致動元件，並且搭配永久磁石、電磁線圈和導磁迴路開發一個磁變形致動器；致動器之磁迴路配置形式和設計也透過磁場有限元素分析軟體深入分析探討，並獲得最佳的致動器效能。透過節流裝置和磁變形致動器作用關係之變化，開發出兩種型式之主動補償式氣壓軸承系統：槓桿式驅動系統和直接驅動式，槓桿式驅動系統藉由槓桿元件將磁變形致動器之位移致動間接轉換到節流間隙之位移調節，直接驅動式則將磁變形致動器整合於節流裝置下方，直接驅動調節節流間隙。直接驅動式系統的節流性能、動態補償特性和無限剛性補償範圍皆優於槓桿驅動式，系統體積亦較為緊緻，並且經過實驗驗證確實具有低頻減振的效果。

關鍵字

氣靜壓軸承 ； 補償式節流裝置 ； 磁變形材料 ； 磁變形致動器 ； 無限剛性

並列摘要

With the progressing tendency of science and technology, the aerostatic bearings become more and more substantial because of their performance of low frictional operation and high rotating precision. In the aerostatic bearings, the restrictor is one of the key functions to improve the stiffness and the stability。The restrictor keeps the pressure of the air-film stable through the regulation of the flow rate, and the increasing stiffness brings about high rotating precision of the spindle. The aim of this thesis is to develop an active compensation restrictor for the aerostatic bearing system, and to study the influences of the design and operation parameters on the load-compensating capability. The slot-restricting principle is adopted for the active compensation restrictor device. Through the theoretical analyses and the finite-element analyses, the influence of slot gap on the supporting capacity is investigated. The regulating function of the restrictor gap is realized by the giant actuating effect of the magnetostrictive material Terfenol-D, which is applied to construct a magnetostrictive actuator together with permanent magnets, a coil and a magnetic circuit. For achieving an optimal actuating performance, the magnetic arrangement in the actuator is analyzed and verified by the finite element magnetic analyses. Through modifying the transferring function between restrictor device and magnetostrictive actuator, we develop two types of active compensation aerostatic bearing systems: the lever-driving system and the directly-driving system. In the lever-driving system, the magnetostrictive displacement is converted to the vertical displacement for regulating the restrictor gap by the lever. And in the directly-driving system, the magnetostrictive actuator integrated under the restrictor can regulate the restrictor gap directly. The system size, flow-restricting performance, dynamic compensation performance and compensating range of infinite-stiffness of the directly-driving system are superior to the lever-driving system. The directly-driving system is also experimentally proved to be able to effectively suppress the low frequency vibration.

並列關鍵字

Aerostatic bearing ； Compensation restrictor ； Magnetostrictive material ； Magnetostrictive actuator ； Infinite stiffness

參考文獻

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