ISSN   1004-0595

CN  62-1224/O4

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球轴承内圈织构表面润滑油滴润湿铺展行为研究

Wetting and Spreading Behaviors of Lubricant Oil Droplets on Inner Ring Textured Surface of Ball Bearing

  • 摘要: 在套圈表面设计微织构已成为轴承润滑增效的一种有效方法,本文中基于VOF (Volume of fluid)理论建立了润滑油滴在球轴承内圈织构化表面润湿铺展的三维数值模型,对比分析了油滴在常规内圈滚道和织构化内圈滚道表面的铺展和润湿特性,剖析了微凹坑织构对润滑油滴铺展的作用机理及影响因素,搭建了液滴动态监测平台与接触角测量平台,将试验结果与数值分析结果进行对比,验证了数值分析的正确性. 结果表明:织构使轴承内圈表面润滑油滴接触角减小、铺展长度和铺展面积增大,提高滚道表面的润湿性;在旋转的内圈滚道表面,织构对润滑油起到存储和滞留作用,使内圈滚道表面润滑油增加、铺展面积增大,形成更加稳定的润滑薄膜,有利于改善轴承内圈润滑状况. 轴承转速越高、织构间距越小、润滑油黏度越小以及油滴初速度越大时,润滑油在旋转滚道表面的铺展面积越大;随着织构深度的增大,油滴铺展面积先增大后减小,40 μm是织构的最佳深度. 该研究对角接触球轴承内圈织构设计以及润滑增效具有重要参考意义.

     

    Abstract: In high-speed mechanical systems, angular contact ball bearings are key transmission components, its performance directly affects the stability and lifespan of entire machinery. Oil-air lubrication is the main lubricate way for angular contact ball bearings, however, due to the centrifugal force, it’s difficult for lubricant oil to maintain on the inner ringway of bearing, resulting in low lubrication efficiency of bearing. In recent years, the continuous advancement of microfabrication technology make it more convenient and efficient to machine concave texture through material removal, and surface texture has become an effective means to improve the lubrication state of friction pairs. In this study surface texture was designed in the inner ringway of bearings, based on VOF theory, a three-dimensional numerical model was established for analyzing the wetting and spreading behaviors of lubricant oil droplets on textured surface of bearing inner ringway. The spreading and wetting characteristics of lubricant oil droplets on conventional and textured inner ring raceways were compared and analyzed, and its mechanism and influence factors are further explored. Dynamic oil droplet monitoring system and contact angle measurement platform were established, and the contact angle of oil droplets on the textured surface and the dynamic spreading process of oil droplets on the textured surface were measured through experiments. The experimental results were compared with the numerical analysis results to verify the correctness of the numerical analysis method. The results indicated that texture can reduce the contact angle of lubricant oil on the raceway surface, increase the spreading length and area on the inner raceway, and improve the wettability of the raceway surface. On the rotating surface of the inner raceway, the texture played a storage and retention role in the diffusion of lubricating oil, increasing the amount and diffusion area of lubricating oil on the inner raceway, which was conducive to forming a more stable oil film and improving bearing lubrication. The texture could decrease contact angular of lubricant oil, increase the spreading length and area on inner raceways, and improve wettability of raceway surface. On rotating surface of inner raceway, texture played a storage and retention role in the spreading of lubricant oil, it increases quantity and spreading area of lubricant oil on inner raceway, which was conducive to forming a more stable oil film and improving bearing lubrication. The higher bearing speed, the smaller texture spacing and lubricant oil viscosity, and the higher initial velocity of oil droplets, result in the larger spreading area of lubricant oil on the rotating raceway surface. As the increase of texture depth, the spreading area of oil droplets first increased and then decreased, 40 μm is the optimal value of texture depth. This study had some reference value for texture designing and lubrication efficiency enhancement of angular contact ball bearings.

     

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