中文摘要 節流器的形式及性能影響軸承的剛度甚巨,由於主動式節流器比固定式節流器有較佳的剛性,所以本研究針對主動式中的薄膜節流器加以探討。本研究主要探討軸承設計中的,軸向油封面長度比及速度、薄膜節流器及節流器中薄膜的補償,在其他固定條件下,採用對向薄膜節流器時,對於單列四腔混壓油腔軸承-轉子系統穩定性的影響。首先分析對稱型混壓軸承使用對向薄膜節流器的靜態、動態性能及其承載轉子或工作台的穩定性,並以工具機靜壓設計準則的建立為最終目標。 本研究使用微擾法將雷諾方程式線性化,並利用有限差分方法及Newton-Raphson法求解油膜及油腔之靜態及動態壓力,接著求出軸承的承載能力,然後藉由Routh-Hurwitz法來判別轉子-軸承系統之穩定性,進而求出系統之穩定性門檻及臨界漩振比。本研究之分析結果以油封面尺寸、速度、薄膜節流及補償等參數對於剛性轉子-軸承系統穩定性上之影響呈現。
Abstract This thesis studies the influence of membrane restriction parameters, speed parameters, land-width ratios and compensated parameters of membrane on the load capacity and stability of a rigid rotor supported by single-row, four-recessed hybrid bearings with membrane compensation. The membrane restrictor is one of the active restrictors, which may significantly offer higher bearing stiffness than the passive restrictors. The objective of this study is to provide the design guideline for machine tool design. The calculation of film dynamics, using the perturbation method, the Reynolds equation was linearized and subsequently solved under finite difference techniques, whilst the determination of stability threshold uses the Routh-Hurwitz method. The load capacity, stability threshold, and the critical whirl ratio, versus the eccentricity ratios, are each simulated for both bearings with various land-width ratios, restrictor parameters and different compensated parameters of membrane. Simulated results indicate that small land sizes with smaller restriction parameters and compensated parameters of membrane are necessary for bearings in order to yield greater stability of rigid rotor-bearing systems.