【作者】 李超；

【导师】 郭峰； 王建；

【作者基本信息】 青岛理工大学 ， 机械工程（专业学位）， 2018， 硕士

【摘要】 由于环境和能源问题,摩擦学领域的研究人员越来越关注润滑油的用量。希望在限量供油(Limited lubricant supply或LLS)条件下实现理想的润滑,即使用极少量润滑油达到有效精准润滑的目的。本研究课题对实验室已有的微滑块轴承润滑油膜测量系统进行了升级改造,并以此试验台进行了有限量供油条件下面接触流体动压润滑研究。完成的主要工作包括:(1)速度实时控制与在线监测单元的建立。采用圆光栅精密测速方案,利用C#语言编写了程序,实现了圆盘速度的实时控制与速度在线监测与存储。(2)摩擦力测量单元的搭建。利用空气轴承,通过杠杆原理放大摩擦力,实现了摩擦力的实时精确测量。(3)有限量供油的实验研究。利用面接触润滑油膜测量系统,使用不同粘度的PAO润滑油在不同的供油量、不同速度、不同载荷、不同回油时间下进行系列实验。有限量供油条件下,接触区入口供油不足形成半月形乏油区域;由于毛细作用的存在,接触区内会聚集更多的润滑油,有利于成膜;随速度的升高,膜厚首先升高,后由于供油不足趋于稳定;定义并使用相对膜厚的概念表述由于供油不足引起的承载力下降,相对膜厚随乏油程度的增加而减小;有限量供油条件下,摩擦力升高较小,有利于润滑。(4)二维有限长数值计算程序的编制。使用差分法求解雷诺方程并利用Fortran语言编写数值计算程序,计算了不同工况下的膜厚摩擦力数据并与实验数据对比,验证了实验系统的准确性。(5)有限量供油条件下承载力的计算。充分供油区域与乏油区域的承载能力计算及实验结果表明当乏油区域较大时,乏油区域内形成部分液桥,具备一定的承载能力,其大小主要受供油量的影响。更多还原

【Abstract】 Due to environmental and energy problems,quantities of lubricants used are now attracting more and more concerns of researchers in the tribology community.It is expected to realize lubrication with limited lubricant supply(LLS),or to obtain efficient and accurate lubrication with very small amounts of lubricant.In the present project an old test rig for film thickness measurement of a slider bearing was updated,and has been used to study the hydrodynamic lubrication in flat-on-flat contact under LLS.The work finished mainly includes:(1)A new unit for real-time control and monitoring of speeds.A precision circular grating was adopted for speed measurement of the disc.A program was written in C# to give accurate speed as a function of time,and as well the monitoring and storage of the real-time speed during the experiment.(2)Construction of friction measurement unit.The unit was designed in such a way that the friction force was enlarged by using an air bearing and the load lever to facilitate the friction measurement.A double-point positioning scheme was proposed and the unstable slider swaying during the old measurement system was significantly suppressed.(3)Experimental studies under LLS.PAOs with different viscosities were tested in different lubricant supply quantities,speeds,loads,reflow time by the new measurement system.With LLS the interferogram is characterized by an inlet starvation area with fragmented/rippled fringes.The starvation area shows a meniscus shape at small and mild starvation.The capillary effect is found to give more lubricant supply at the boundary of starvation area within the contact,and contribute the formation of the side ridges of the lubricant layer on the running track.With increasing speeds,the film thickness increases at first and then remains nearly unchanged due to enlargement of the starvation.A relative film thickness is defined and used to evaluate the decrease of load-carrying capacity caused by LLS.When starvation grows the relative film thickness decreases.Results showed that the lubricant viscosity and the reflow time between two slide-overs can markedly affect the film building.Under the condition of LLS,the friction increased slightly,which is beneficial to lubrication.(4)Two-dimensional numerical calculation program for hydrodynamic lubricaiton.The finite difference method was used to solve the Reynolds equation and a computation program has been written in FORTRAN.The film thickness and friction under different working conditions were calculated and compared with the experimental data,and the accuracy of the experimental system was verified.(5)Calculation of load-carrying capacity under LLS.According to the shape of the starvation area,the load-carrying capacity of the starvation area and full film area is calculated.Comparison between experiments and numerical calculations showed that the starvation area can bear some of the load.At present it is thought that the local tiny full film fragments/oil bridges may be responsible for the load.更多还原