預壓力對高負荷滾珠元件於油潤滑情形下之磨潤性能影響

由於滾珠摩擦遠小於滑動摩擦，因此許多運動元件內含有滾珠，例如滾珠螺桿、滾動軸承等關鍵零組件，然而不論滾珠軸承或滾珠螺桿在運轉中會有背隙產生，因此安裝滾珠時會給予一預壓力以消除背隙與提高效率。本實驗創新設計一個模擬滾珠於螺帽與螺桿之間或於軸承外環與內環之運動情形的機械模組，藉由不同徑向負載、側向負載(預壓力)、轉速條件下，研究其磨潤特性並比較未考慮機械之元件側向力之性能差異，並歸納出接觸角度與負載之關係，以作為設計參考。　　實驗結果顯示正向負載與轉速的提升會增加摩擦係數進而使溫度提高，在側向負載部份，施加側向負載後對溫度影響不大但有減少摩擦係數之效應，此與理論分析的趨勢一致，實驗發現接觸角度會隨側向負載增加而提升，接觸角度的提升有助於降低摩擦係數及溫度降低，藉此可提高機械之使用壽命，此外透過在相同正向負載、不同側向負載與接觸角度之關係，推導出公式如下： Case1 : 1.59 Gpa~1.89 Gpa θ=(L/N)0.57＊32.22，相對誤差：6.8% Case2 : 2.01 Gpa~2.89 Gpa θ=(L/N)0.49＊48.37，相對誤差：7.0% Case3 : 2.55 Gpa~3.18 Gpa θ=(L/N)0.37＊55.69，相對誤差：4.5%

關鍵字

滾珠螺桿；預壓力；接觸角；滾珠；磨潤

並列摘要

Since ball friction is much smaller than sliding friction, many motion components contain balls, for example, the key components such as a ball screw and a ball bearing. However, both the ball bearing and the ball screw can generate back clearance in motion, thus a preload will be given in ball installation to eliminate back clearance and improve efficiency. The experiment innovatively designs a mechanical module which simulates a ball between a nut and a screw or between the outer ring and inner ring of a bearing in different directional load, lateral load (preload) and rotating speeds, to research its tribological performance and compare lateral performance difference of unconsidered mechanical components, as well as summarize the relationship between contact angle and load as design reference. 　　The experimental results show that increase of positive load and rotating speed can increase frictional coefficient further to make the temperature rise. In lateral load, temperature is not obviously affected but the frictional coefficient is reduced after lateral load is imposed, which is in accordance with theoretical analysis. The experiment finds that contact angle will increase as the lateral load increases; increase of contact angle helps to reduce frictional coefficient and temperature, which can be used to improve service life of a machine. In addition, the following formula is deduced according to the relationship among the same positive load, different lateral load and contact angle: Case1：1.59 Gpa~1.89 Gpa θ=(L/N)0.57＊32.22，relative error：6.8% Case2：2.01 Gpa~2.89 Gpa θ=(L/N)0.49＊48.37，relative error：7.0% Case3：2.55 Gpa~3.18 Gpa θ=(L/N)0.37＊55.69，relative error：4.5%

並列關鍵字

Ball Screw ； Preload ； Contact Angle ； ball ； Lubrication

參考文獻

[3]Jones A. B., 1960, ”A General Theory for Elastically Constrained Ball and Radial Roller Bearings Under Arbitrary Load and Speed Conditions”, Journal of Basic Engineering, Transactions of the ASME, Vol.82, pp.309-302.

[4]Harris T. A., 1971, ”An Analytical Method to Predict Skidding In Thrust-loaded, Angular-Contact Ball Bearings”, ASME Journal of Lubrication Technology, pp. 17–24.

[5]Harris T. A., 1984, ”Rolling Bearing Analysis”, John Wiley & Sons, New York.

[7]CHEN H. S., 1970, ”A Numerical Solution of the Elastohydrodynamic Lubrication Problem Using Finite Elements”, Journal of Lubrication Technology, Transactions of the ASME, pp.155~162.

[8]Spence E. W., Kaminski D. A., 1996, ”Thermal Evaluation of a Dry Nonrotating Thin Section Contact Bearing”, ASME, Journal of Manufacturing Science and Engineering, Vol.118, pp. 610-614.

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預壓力對高負荷滾珠元件於油潤滑情形下之磨潤性能影響

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