【作者】 卓会丹；

【导师】 宋宝玉；

【作者基本信息】 哈尔滨工业大学 ， 机械设计及理论， 2011， 硕士

【摘要】 自润滑陶瓷轴承的润滑剂来源包括自润滑复合材料保持架、滚道表面改性润滑膜和滚动体表面改性润滑膜。随着无保持架满装氮化硅陶瓷球轴承的广泛应用,对滚动体表面的润滑改性的需求日趋强烈。具有高硬度、低摩擦系数、高耐磨性及高化学稳定性的类金刚石碳膜,作为固体润滑剂在航空航天领域得到广泛应用。在高温环境下,陶瓷表面润滑薄膜的承载能力除了与机械变形应力有关外,还与工作过程中的界面热应力关系密切。本文利用接触力学、断裂力学以及热力学模型,通过实验、理论分析及软件仿真等方法,从薄膜经历不同温度循环后的的力学性能变化、滚动摩擦效应及高温滑动摩擦磨损性能三方面系统地研究了陶瓷表面DLC膜的热特性,为陶瓷表面改性润滑膜的实际应用提供基础。膜基结合力是氮化硅陶瓷表面DLC膜能起到润滑作用的前提条件,而且这种膜基结合力在热作用下要有一定的保持能力。本文通过纳米压痕和划痕试验,对经过不同温度热循环后的陶瓷片和陶瓷球表面DLC膜在正压力、正压力和切向力共同作用下的承载能力、膜基结合力进行研究,分析了DLC膜经过不同温度热循环后的力学性能变化。为氮化硅陶瓷基上DLC膜的实际应用奠定理论基础。使用Ansys有限元模型模拟计算了DLC膜的热应力,分析了不同工作温度下薄膜的热应力的大小和分布。利用高温摩擦磨损试验机,通过试验参数选择,分析陶瓷基底表面DLC膜在不同温度以及在高温环境下承受不同载荷和不同滑动速度时的摩擦磨损性能,并分析DLC膜在高温环境中的磨损机制,找到DLC膜在高温环境下工作的最佳温度区域以及在此温度区域内膜承载的临界载荷和速度区域。同时结合利用有限元模型计算的热应力结果,分析了DLC膜的热承载特性,为高温环境下陶瓷基体上DLC膜的实际应用奠定理论基础。最后采用经验模型理论计算分析轴承摩擦力矩,利用BRG3000摩擦力矩测试仪测试镀膜陶瓷球轴承的动态摩擦力矩,通过不同润滑方式之间轴承摩擦力矩的比较以及实验参数选择,研究DLC薄膜的滚动摩擦效应,提供DLC薄膜在轴承中的应用和评测手段。更多还原

【Abstract】 The lubricant sources of self lubricating ceramic bearings include composite cages of self lubricating, the lubricating film of raceway surface modification and rolling surface modification. The widely application of silicon nitride ceramic ball bearing that without cages results in increasing need of lubrication with rolling surface modification. Diamond like carbon film, which was regarded as a solid lubricant with high wear resistance, low friction coefficient, high hardness and high chemical stability, was widely used in aerospace. However, under high temperature working condition, load carrying capacity of ceramic surface lubricating film not only have a great relationship with mechanical stress, but also with the interface thermal stress resulting from working process.By constructing contact mechanics, fracture mechanics and thermodynamics models, applying experimental analysis and simulation methods, this dissertation studied thermal characteristics ceramic surface DLC film, which contain the changes in the mechanical properties and effects of rolling friction after experiencing different temperatures cycling, sliding friction and wear properties at high temperature. These studies provide foundation for applications of modification film on the ceramic surface.Film adhesion is the bases of the silicon nitride ceramic surface DLC film working as lubricant, and the adhesion must be maintained under the effect of the heat. With nanometer indentation and scratch tests, bearing capacities and adhesion force between DLC film and the base are analyzed. The DLC films on the surface of ceramics plate and ball have experienced thermal cycles at different temperatures under positive pressure and shear force, and analyze the changes in the mechanical properties of the DLC film which were experienced thermal cycles at different temperatures. The dissertation provides theoretical basis for practical application of DLC films on silicon nitride ceramic.The model of Ansys finite element was employed to simulate the size and distribution of thermal stress of thin films under different working temperatures. By applying High Temperature Tribometer and selecting peoper experiment parameters, this dissertation studied the DLC film’s tribological behavior under, different temperatures, loads and speeds, analyzed the wear mechanism under different conditions, got optimum temperature ranges in which DLC film can well perform as the lubricant, and obtained the critical load and critical speed at high temperature. Combined with the heat stress results from finite element model, the thermalload characteristics of DLC films was analyzed, which provides the theoretical basis for the DLC film’s application at high temperature.Finally, bearing’s friction torque was calculated based on the empirical model, dynamic friction torque of the coated ceramic ball bearing was tested with the tester of BRG3000 Torque, the effect of rolling friction DLC films was studied by comparing the friction torque at different lubrication and experimental parameters, which provides the application and evaluation tools for DLC films’application in bearings.更多还原