【作者】 刘伟；

【导师】 赵自强；

【作者基本信息】 北京理工大学 ， 机械设计及理论， 2016， 硕士

【摘要】 轴承是装备制造业中重要、关键基础零部件,随着现代装备向高速重载方向发展,对滚动轴承的承载能力、动态性能、可靠性、运转精度等方面提出了越来越高的要求。在高速工况下,发热会对轴承的游隙、润滑接触性能产生较大的影响。因此,基于热效应对滚动轴承进行动态性能分析具有重要意义。在高精密工况条件下,各类轴承缺陷将以内部激励的形式对滚动轴承的动力学行为产生十分显著的影响。因此,迫切需要系统研究各类轴承缺陷对滚动轴承动力学性能的影响规律,从而揭示其内在机制,为提升机械装备系统性能提供理论依据。本文首先基于滚动轴承的运动学方程,考虑了高速工况下离心力和陀螺力矩的影响,以及受载工况下摩擦生热产生的轴承元件热变形,结合滚动轴承的受力平衡方程,建立了角接触球轴承的分析模型,求解出钢球与内、外滚道之间的接触载荷、接触应力以及惯性力,分析了热效应对轴承性能的影响。结果表明:考虑热效应之后,钢球与外滚道之间的接触载荷和接触应力同时变大,与内滚道之间的接触载荷和接触应力同时变小,热效应对轴承的惯性力和轴向位移几乎没有影响。并基于坐标对等原则改进了轴承的运动学方程,两种方法计算结果吻合良好,而新方法的计算效率较高。然后以深沟球轴承为对象,考虑了油膜阻尼和油膜切向摩擦力,得到了滚动轴承的运动微分方程,建立了更符合实际的滚动轴承动力学模型,此模型并不受初值选取大小的影响,求解特定工况下轴承-转子系统内圈中心的位移和速度,与未考虑油膜影响的计算进行了比较;并在考虑滚道的表面波纹度和凹坑的前提下,分析了油膜对轴承动力学特性的影响,润滑油膜的存在有利于减小轴承的振动。以角接触球轴承为例,综合考虑了温升引起的热变形和油膜阻尼后,建立了轴承的运动微分方程,研究了不同工况下表面波纹度和缺陷对角接触球轴承动力学性能的影响。研究表明:轴向预紧力能增加轴承的刚度,减小振动,但是外加载荷增加,会增大轴承的摩擦热,降低轴承的寿命;表面波纹度和凹坑缺陷对于角接触球轴承振动的影响取决于具体的工况条件;热效应使轴承工作时的振动减弱,但是会加剧表面波纹度对轴承运转精度的影响。更多还原

【Abstract】 Bearing is the key component in equipment manufacturing industry. With the development of modern equipment to high-speed, heavy load conditions, there are increasing demands on load capacity, dynamic performance, reliability and running accuracy of bearing. Under the high-speed conditions, frictional heating greatly affects bearing clearance and lubricated contact performance. Accordingly, it’s very important to analyze dynamic performance of rolling bearing with consideration of thermal effect. In the case of high precision operating conditions, most bearing defects will have significant influence on dynamic behavior of rolling bearings as an internal incentive, which implies that systematic research on the effect of on dynamic behavior of rolling bearings is desirable in a hurry. Then we could explain the internal patterns and provide theoretical basis to improve performance of mechanical equipment.Angular contact ball bearing is modeled with the consideration of centrifugal force and gyroscopic torque under high-speed conditions, the thermal deformation of bearing component, which can obtain the contact force, contact pressure and inertia force between inner and outer raceways, and analyze the impact of thermal effect to bearing performance. The result showed that the contact force and contact pressure in outer raceway get bigger and those in inner raceway get smaller due to the thermal deformation, while thermal effect has barely impact on centrifugal force, gyroscopic torque and axial displacement of bearing. The model is further improved based on coordinate equivalence, which has high computational efficiency.For the deep groove ball bearings, the bearing differential equations of motion are established with consideration of the oil film damping and the tangential friction, which is much close to the actual working conditions and not sensitive to the initial solution guess. The displacement and speed of the inner raceway center are compared with the case without considering the effect of oil film; the effect of oil film on the bearing dynamics is investigated with the consideration of waviness and surface, which shows that the presence of the lubricant oil film tends to reduce the bearing vibration.The dynamic model of angular contact ball bearing is developed with further considering the combined effect of thermal deformation and oil film damping. The results show that, axial preload could enhance bearing stiffness, decrease vibration, but increase frictional heat, and shorten bearing life; the impact of waviness and dent on vibration of angular contact ball bearing depends on the actual conditions; thermal effect could decrease vibration, while aggravate the impact of waviness on running accuracy of bearing.更多还原