Hydrodynamic lubrication of rubber seals for reciprocating motion; leakage of seals with an O-ring

The solution of design and operational problems in sealing technology requires definition of the lubrication parameters underneath the sealing ring. Knowledge of the film thickness enables one to define the out-leakage, the most important sealing parameter. A review of theoretical and experimental equations defining the lubricating film thickness is presented. An original method of measuring the film thickness is described, and an attempt is made to explain the differences that exist between the theoretical and experimental equations.     

液压往复密封理论、技术与应用的进展研究

综述了液压往复密封偶合面的摩擦、磨损和润滑,从边界润滑液膜的形成,密封失效的机制和动力润滑密封方面,评述了液压往复密封理论的研究进展。通过液压往复密封的结构设计方法、材料、应用及其技术进展分析,提出密封件截面形状的变化、新型的组合密封仍是未来往复密封的主要结构形式,密封性能和耐磨特性的改善和提高,密封结构和材料的进一步分离,往复密封的可控性提高、系统内部资源的充分利用是未来往复密封的研究热点和发展趋势。     

O形圈动密封特性的有限元分析

利用软件ABAQUS建立了O形圈的轴对称有限元模型,分析了其在往复动密封中的密封性能,并对其不同工况下的力学性能进行了研究。结果表明:往复动密封中,O形圈主密封面最大接触应力与Von Mises应力的作用位置随运动方向的变化而改变,且大小随时间呈波动变化;速度小于0.25 m/s时,速度对摩擦力与剪切应力几乎无影响;随着摩擦系数、介质压力的增大,摩擦力与剪切应力对速度的敏感性变高;介质压力与摩擦系数对摩擦力与剪切应力影响较大,剪切应力与摩擦力呈同步变化;密封外行程Von Mises应力与剪切应力均大于内行程,更易引起疲劳与剪切破坏;预压缩率增加到一定值时,O形圈在动密封中所受的摩擦力急剧上升,动密封中预压缩率不宜过大。     

Effectiveness of lubricant additives for copper‐alloy‐steel sliding contacts

A selection of additives and their performance and compatibility with a variety of copper alloys have been evaluated in an SRV test set‐up. The tests show a remarkable variation of tribological behaviour with a clear relation to both the type of lubricant / additive and the type of alloy. One ester‐based additive showed outstanding friction and wear reduction for some groups of copper alloys. In order to better understand the fundamental mechanisms, we applied a variety of surface analyses, such as 3D confocal white light microscopy, scanning electron microscopy and X‐ray photoelectron microscopy. Copyright © 2010 John Wiley & Sons, Ltd.     

Friction and wear properties of Fe7Mo6-based alloy in ethyl alcohol

In this study, the friction and wear properties of Fe₇Mo₆-based alloy, Fe and Mo disk specimens sliding against ASTM 52100 steel and Cu and SiC ball (or pin) specimens in ethyl alcohol were evaluated using an Optimol SRV oscillating friction and wear tester. The Fe₇Mo₆-based alloy disk specimens exhibited more stable friction coefficients than the Fe and Mo disk specimens when slid against the ASTM 52100 steel ball specimen. On the other hand, the Fe/SiC tribo-pairs exhibited the lowest average friction coefficients (0.14-0.17).