側向力對接觸面積增長與接觸角影響研究

The Effect of Lateral Force on the Junction Growth and Contact Angle

游凱文(Kai-Wen You)

指導教授 ： 洪政豪

國立虎尾科技大學/工程學院/機械與機電工程研究所/碩士(2012年)

https://doi.org/10.6827/NFU.2012.00212

摘要

目前對精密元件的界面研究中大多數只有探討正向力的影響，然而在實際系統機台運作時，元件常承受部分側向力，因此亟須了解側向力對機械元件作動時的磨潤性能影響，以掌握精密元件之性能變化並改善與提升機械產業之生產品質。
本實驗透過多功能磨潤試驗機及側向負荷裝置來模擬接觸元件運動情形，目的在分析點接觸元件在不同側向力下接觸時的溫度、摩擦係數、電阻與面積增長等，及與只有受到正向負荷的機械效率差異性；在面積增長研究中，使用微接觸磨潤試驗台，利用光學量測方法進行微觀界面實驗，觀測半圓體及半橢圓體之黃銅金屬於石英玻璃之平坦面上，先行施加正向預負荷，再給予一滑動速率後產生滑動與側向推力，並探討不同橢圓率粗糙峰承受各種不同之正向負荷與滑動速度後，接觸界面面積增長及幾何形狀的變化，並了解摩擦力與變形量在不同接觸界面間磨潤特性的影響。
側向力試驗結果顯示，側向負荷/正向負荷比( L/N force ratio )在2/3以下時，相同正向負荷條件下，接觸角將隨著側向負荷的增加而增加，並推導出公式為 θ= C ( L/N ) 且摩擦係數將隨著接觸角的增加而下降，摩擦係數下降導致油膜電阻值的上升，隨著接觸角的增加試件溫度與油溫之溫升趨勢減緩。由實驗結果顯示，不同側向負荷/正向負荷比對表面接觸性能表現並不相同。微接觸實驗結果顯示，當相互接觸之兩物體產生滑動時，其壓縮變形趨勢為非線性，大部分壓縮變形都發生於滑動600?m內初始階段。壓縮變形量與正向負荷、滑動速度成正比關係，實驗範圍內（0.75Gpa~1.4Gpa）摩擦係數與正向負荷一般則呈現反比關係。

關鍵字

側向力 ； 微接觸理論 ； 摩擦 ； 接觸角 ； 油膜電阻值 ； 油膜厚度 ； 交界面

並列摘要

The junction study of the business of manufacturing of machine for precision components, most of studies are only consider the effect of normal force. However, when the real system of machine operated, components often received some lateral force. So when machine components operated, the effect of tribology properties will become more important, understand diversification of the properties of precision components, improve and promote the production quality of manufacturing of machine.
In this paper, the multi-function tribology test machine and lateral force machine were conducted to study tribological properties of sliding pair of components in combing normal and lateral force situations. Experimental parameters include the friction coefficient, contact resistance, oil temperature, workpiece temperature and contact angle between two components. The junction growth on surface of study used optical measurement methods to perform experiments on starting junctions, observing half-circle and half-ellipse bodies of yellow copper on a hard, smooth quartz surface. A positive pre-load was added in advance. Following the addition of an extra sliding load, the red copper test specimens began to slide on the platform. After investigating the asperity of differing measurements and forms developed under various positive loads and sliding speeds, the size of the contact junction surfaces increased, and their shapes changed. A further understanding of the influence exerted by friction forces on the properties of two different contact junctions was obtained.
The results of lateral force machine show that the friction coefficient decreases and contact angle increases as lateral force increases. It results in the oil and workpiece temperature decrease when L/N force ratio increases. The relationship between contact angle and L/N force ratio can be represented as a simple equation: θ=C (L/N). The results of multi-function tribology test machine indicate that when sliding occurs in the contact between two objects, their junction growth and compression universally trend toward nonlinearity. The majority of compression occur in the initial stages of sliding, within 300?m. The degree of compression is positively related to the positive load and sliding speed. Within the range of this experiment (0.75 GPa ~ 1.4 GPa), the friction increased with normal load decreased, the compression increased with normal load increase, and the compression increased with sliding velocity decreased.

並列關鍵字

lateral force ； micro-contact mechanics ； friction ； contact angle ； contact resistance ； film thickness ； junction

參考文獻

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