ass日本风韵熟妇pics男人扒开女人屁屁桶到爽|扒开胸露出奶头亲吻视频|邻居少妇的诱惑|人人妻在线播放|日日摸夜夜摸狠狠摸婷婷|制服 丝袜 人妻|激情熟妇中文字幕|看黄色欧美特一级|日本av人妻系列|高潮对白av,丰满岳妇乱熟妇之荡,日本丰满熟妇乱又伦,日韩欧美一区二区三区在线

A novel method was proposed to improve surface quality of bearing friction pair with nanometer grind technology. Using special nanometer material, mechanical grind and chemical abrasion were implemented at the same time. The grinding mechanism, characteristics of each grinding materials, and processing technology of new method were accounted in detail. With quantity of experiments on different kinds of bearings, measuring and analyzing surface morphology of friction pair, it is found that the chemical grinding method could effectively improve bearing's surface morphology, reduce running vibration and noise, and increase bearing's quality.