微观拓扑结构对动静压轴承转子系统动力学稳定性影响的机理研究

High-speed spindle supported by the hybrid bearing is one of the preferred spindle support solution in the future, because of its high precision and high stiffness. In this project, we propose a new technique to improve the hybrid bearing supported spindle rotation accuracy, which is based on micro-topology. We have carried out some early exploratory experiments and the results showed: the vibration amplitude of the textured journal can decease up to 60% compared with non-textured journal under unbalanced loading conditions. There is, however, no reasonable explanation for this phenomenon. Based on this observed microstructure suppression phenomenon, we will advance a deterministic multi-scale computation method for texture-hybrid bearing lubrication problem under complex boundary condition, and carry out a systematic study of the texture effect to the hybrid-bearing performance, establish the texture-hybrid bearing-rotor dynamic model, examine the texture effect to the stability of rotor-bearing system. By comparison of theoretical analysis, numerical simulation and experiment, the mechanism of texture vibration suppression will be revealed, and the key texture parameters will be identified and optimized. Finally, we will establish the texture design criteria for the spindle vibration suppression, build the theoretical frame of vibration suppression system based on the texturing technique. This project will improve the accuracy of precision spindle rotation and has potential engineering applications.

动静压轴承支撑高速主轴具有高精度、高刚度等优点，是未来高速精密机床的首选方案之一，回转精度是评价其整体性能的重要指标。为了提高机床高速主轴的回转精度，申请人开展了探索性试验，发现动静压轴承支撑主轴在同频强迫振动条件下，具有微结构的主轴相对于光滑主轴在轴颈处的振幅最高可下降60%！鉴于目前尚无理论可以对这种抑制转子的振动现象进行合理说明，申请人提出基于微观拓扑结构改善动静压轴承支撑主轴动力学特性的研究方案。项目将探索大规模微结构存在条件下动静压轴承油膜力的快速计算方法，分析微结构对动静压轴承润滑特性的影响机制；建立微观拓扑结构—动静压轴承—转子系统的动力学模型，揭示微结构对转子轴承系统稳定性的影响机理；通过理论和试验对比研究，阐明大规模微结构抑振现象的科学实质；最终，识别并优化微结构关键抑振参数；确定微结构抑振的适用范围和条件，给出微结构抑振的设计准则，构建较为完整的微结构抑振理论体系。

基于试验发现的微结构对滑动轴承支撑转子的抑振现象，本项目提出了基于微观拓扑结构改善动静压轴承支撑主轴动力学特性的研究方案，探索了大规模微结构存在条件下动静压轴承油膜力的快速计算方法，建立了微观拓扑结构一动静压轴承一转子系统的动力学模型，揭示了微结构对转子轴承系统稳定性的影响机理；开发了基于有限细胞法的轴承多尺度润滑计算方法，相对于传统有限元/有限差分法，同等计算资源条件下，计算规模扩大两个数量级；提出了基于Garlerkin思想的油膜压力快速求解方法，计算精度与传统方法相当，计算速度提高一个数量级；分析了微结构对动静压轴承润滑特性的影响机制，探究了微观拓扑结构对环面节流器节流系数的影响，总结了微观拓扑结构对径向动、静压轴承、推力轴承液膜流场与润滑特性的影响规律；通过理论、仿真对比研究，阐明了大规模微观拓扑结构对转子轴承系统动力学稳定性的影响机理；总结了微观拓扑结构对错位瓦轴承转子系统、环槽轴承支撑转子系统的动力学稳定性的影响规律，构建了微结构抑振理论体系；本项目的研究成果重要的科学价值和较强的工程应用前景。