面接触限量供油润滑的自集油增强功能表面调控

With exploration for the proposed strategy of liquid film lubrication in miniature devices and measures of less lubricant usage in precision mechanical units, lubrication with limited lubricant supply (LLS) has attracted more and more attention. Enhancing lubricant replenishment on the lubricated surfaces is a key in the LLS lubrication, however there is knowledge vacuum in this area. Therefore this project is proposed for an idea of functional surfaces with enhanced lubricant replenishment by patterned wettability to achieve desired lubricant migration and distributions with different surface-to-volume ratios for efficient lubrication under flat-on-flat contact. The main work will include: 1) To develop a fluorescence-based measuring system for lubricant distribution on the lubrication track. 2) To investigate the influence of surface wettability on oil film thickness and friction of flat-on-flat contact with limited lubricant supply. 3) To study design principles of the functional surfaces with enhanced lubricant replenishment for lubricant distributions of stripes, meshes and droplets. 4) To experimentally study the lubrication behaviors with limited lubricant supply under functional surfaces with enhanced lubricant replenishment. 5) To build a mathematical model for theoretical analyses of thin hydrodynamic lubrication with limited lubricant supply, and thereafter to study the mechanism of the functional surfaces with enhanced lubricant replenishment. In this project the effect on oil lubrication of the functional surfaces with enhanced lubricant replenishment will be first-ever demonstrated. And in the meaning time the relationship between the lubricant quantity and the parameters of the functional surface under efficient lubrication will also be presented. The theory and the data obtained will be beneficial to the tribological design of liquid lubrication, and of course contribute to the energy saving and environmental protection.

随着对微器件液体润滑策略的探索和精密部件少油量润滑技术的需求，限量供油润滑正引起越来越多的关注，提高表面的自集油能力是其中关键问题之一，但相关研究匮乏。为此本课题针对面接触限量供油润滑，提出构造基于图案润湿的自集油增强功能表面，实现润滑剂的定向迁移及不同面体比的润滑剂分布，提高限量供油润滑效率。主要研究内容包括：1）润滑轨道表面润滑油分布的荧光定量测量。2）表面润湿性对面接触限量供油润滑膜厚与摩擦力的影响。3）针对润滑油条状、微网状和微液滴状分布，研究自集油增强功能表面的设计与制备。4）自集油增强功能表面作用下面接触限量供油润滑的实验研究。5）面接触限量供油润滑及表面自集油效应的理论分析。本项目将初次验证“油膜润滑的自集油增强功能表面调控”概念的有效性，给出有效润滑条件下供油量与自集油增强功能表面特性参数的定量关系。研究成果为限量供油润滑提供新的理论知识，也贡献于节能和环保的社会需求。

限量供油润滑（Limited lubricant supply，LLS）使用有限量的润滑油对摩擦副进行精准润滑，使零部件工作在降磨减摩最佳润滑状态，降低摩擦功耗，正成为摩擦学设计的新趋势。在限量供油润滑中，理论上可以通过合理的表/界面设计，实现摩擦表面自集油（oil replenishment）的主动控制，从而对润滑行为进行优化。但已有的研究并未关注该领域。本项目即在此背景下开展，从实验和理论两方面探索，通过表界面效应进行摩擦表面自集油增强功能的调控。完成的工作包括：1)升级已有的面接触油膜润滑测量系统，增加了润滑油分布荧光定量测量功能。借助新的系统，研究了限量供油条件下面接触油膜润滑的基本特性。2）在限量供油条件下研究了表面润湿性对润滑膜厚与摩擦力的影响。发现了低表面能表面诱发的润滑油离散分布增加油膜承载力这一反常现象。针对高应力点接触，揭示了油滴供油诱发凹坑油膜的本质和规律。提出了离散供油的油膜润滑模型，解释了离散限量供油的油膜形成机制。3）制备了自集油增强的功能表面，研究了其对限量供油润滑的影响规律。利用化学修饰和飞秒激光两种方法，设计和制备了条状润湿、间隔润湿及三维梳齿沟槽（3d-CTG）等三类自集油增强的表面，并进行了润滑油输运能力的表征。结果表明在有限量供油条件下，制备的自集油增强功能表面产生的润滑油膜有较强的承载力和显著的抗磨减磨性能。4）设计并测试了带有自集油增强功能表面的低摩化轴承。在轴承的内圈制备了条状润湿的自集油增强表面。实验室测试表明，该新型轴承的摩擦力矩明显低于普通轴承。在此基础上，为青岛泰德汽车轴承股份有限公司设计了新型的低摩擦轴承，与公司的常规产品相比，擦力矩降低明显。本项目针对限量供油润滑对自集油增强功能表面调控进行了系统的实验和理论研究，并将理论成果应用于轴承的低摩化，取得了很好的效果。研究成果为限量供油润滑技术提供新的理论知识，也贡献于节能和环保的社会需求。