小型人字形凹槽非牛頓磁性流體軸承之動態分析與實驗驗證

光碟機資料儲存密度非常高，若要提高資料的傳輸速率，則主軸馬達的轉速必須再提升。使得整個光碟機的振動增加，並造成馬達軸承的磨耗與壽命的降低，光碟機其它組件也有可能因此而損壞。因此設計一個良好的軸承來增加主軸剛性及軸承本身之壽命即為減少主軸振動之重要因素。因此，本文將研究小型人字形凹槽非牛頓磁性流體軸承之動態分析與實驗驗證，首先建立小型人字形凹槽非牛頓磁性流體軸承數學模型，以奈威爾-史托克方程式為基礎，發展非牛頓磁性流體軸承。非牛頓流模式採用Rabinowitsch 關係式，分析三種不同磁場模式非牛頓磁性流體軸承性能參數之影響。本研究採用有限差分法的SIMPLE(Semi-Implicit Method for Pressure-Linked Equations)演算法，利用容積流模式求解軸承中壓力、速度和黏度。另外，採用現有軸承實驗平台機構加入磁性流體之小型人字形凹槽軸承的動態參數做量測。從量測結果分析磁性潤滑油在外加磁場影響，磁性流體軸承在外加磁場下比無外加磁場剛性提升28%。

關鍵字

非牛頓磁性流體；人字形凹槽軸承；有限差分法

並列摘要

The data storage density is very high on a CD-Disc. To increase the data transmission speed, then the core bearing speed has to increase as well. This, unfortunately, will intense vibrations for the CD-ROM, and increase the attrition rate and shorten the lifetime for the core bearing. What is worse, the CD-Rom and its components might be damaged as well. Thus, a good design for the bearing should incorporate such factors as the rigidness and the lifetime of the bearing to alleviate vibration for the bearing. Therefore, this study first conducted a dynamic analysis and experimental verification on the Small-sized Herringbone-grooved bearing with Non-Newtonian Magnetic Fluid. A mathematical model of the HGJB was constructed, and a non-Newtonian magnetic fluid bearing is developed based on the Navier-Stokes equation. The study adopted the non-Newtonian fluid model with the Rabinowitsch equation to analyze three different kinds of magnetic fields. This study uses finite difference method and adopted the Semi-Implicit Method for Pressure-Linked Equations. The optimum pressure value and speed value are both acquired using the Bulk-Flow Model. This study then tested the proposed model with dynamic parameters. The study results indicates that the bearing, while magnetically lubricated and influenced by external magnetic fields, can bear stronger rotating force than otherwise.

並列關鍵字

Herringbone groove bearing ； finite difference method ； non-Newtonian magnetic-fluid

參考文獻

[21] 陳俊名，“小型液態軸承之動態特性量測實驗系統的設計與建構”，碩士論文，中原大學，2004。

[2] J. H. Vohr, and C. Y. Chow, “Characteristics of Herringbone-Grooved Gas-Lubricated Journal Bearings,” ASME Journal of Basic Engineering, pp. 558-569, 1965.

[4] F. Sorge, “A Numerical Approach to Finite Journal Bearings Lubricated with Ferrofluid,” ASME Journal of Tribology, vol. 109, pp. 77-82, 1987.

[5] T. A. Osman, “Misalignment Effect on the Static Characteristics of Magnetized Journal Bearing Fubricated with Ferrofluid,” Tribology Letters, vol. 11, no. 3-4, pp.195-203, 2001.

[7] T. A. Osman, G. S. Nada and Z. S. Safar, “Static and Dynamic Characteristics of Magnetized Journal Bearings Lubricated with Ferrofluid,” Tribology Intrnational, vol. 34, pp. 369-380, 2001.

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小型人字形凹槽非牛頓磁性流體軸承之動態分析與實驗驗證

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