表面特性和流體膜厚度對液靜壓軸承靜摩擦係數的影響

Effects of Surface Characteristics and Fluid Film Thickness on the Coefficient of Static Friction of a Hydrostatic Bearing

黃宗堂(Tzung-Tang Huang)

指導教授 ： 林士傑

國立清華大學/工學院/動力機械工程學系/碩士(2018年)

摘要

液靜壓軸承採用外部加壓源，泵送潤滑劑在移動軸承面之間形成油膜。液靜壓軸承基本上具有零到無磨損、低摩擦和高阻尼能力的特性。油膜的厚度受節流器與軸承的設計、軸承的負載及供油壓力等因素的影響。這一點的重要性在於，當流體膜厚度較小時，組件之間可能會有接觸，因此磨損和摩擦可能會急劇增加。通常，流體膜厚度越小，軸承的剛度越大。但是，流體膜厚度小的時候，可能導致機器部件之間有接觸。因此，本研究旨在研究表面特性和流體膜厚度對液靜壓軸承靜摩擦係數的影響。本研究將利用可調式毛細管節流器將流體膜厚度調整到所需厚度，並測試引導線性滑塊移動所需的力量，從而得出小流體膜厚度如何影響液靜壓軸承的性能。

關鍵字

液靜壓軸承 ； 表面粗糙度 ； 靜摩擦 ； 流體膜厚度

並列摘要

Hydrostatic bearings utilize an externally pressurized source that pumps in lubricant to create a film between the moving bearing faces. Hydrostatic bearings have the characteristics of having essentially zero to no wear, low friction, and high damping
capabilities. The thickness of this fluid film is affected by the design of the restrictor and bearing, load on the bearing, the source pressure et al. The importance of this is that at small film thicknesses, there may be solid-to-solid contact between the
components. Thus, the wear and friction may drastically increase.
In general, the thinner the film thickness, the greater the resulting stiffness of the bearing. However, thin film thicknesses may cause solid-to-solid contact of the machine parts. Thus, this study aims to investigate the effects of surface characteristics such as surface roughness and film thickness on the coefficient of static friction of a hydrostatic bearing. This study will utilize a variable capillary restrictor to adjust the film thicknesses to
the desired levels and test the amount of force required to induce movement in a linear guide-way carriage, thus, giving a quantitative result about how a small film thickness might affect the performance of the hydrostatic bearing.

並列關鍵字

hydrostatic ； bearing ； surface ； roughness ； static ； friction ； film ； thickness

參考文獻

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[2] W.B. Rowe, Hydrostatic, Aerostatic, and Hybrid Bearing Design, Waltham: Butterworth-Heinemann, 2012.

[3] C. Cusano, "Characteristic of Externally Pressurized Journal Bearings with Membrane-type Variable-Flow Restrictors as Compensating Elements," in Proceedings of the Institution of Mechanical Engineers, 1974.

[4] M. Mohsin, "The Use of Controlled Restrictors for Compensating Hydrostatic Bearings," in Advances in Machine Tool Design and Research, 1962.

[5] B. Piccigallo and R. Bassani, Hydrostatic Lubrication, Amsterdam: Elsevier Science Publishers, 1992.