考虑挠度的宽温域陶瓷轴承转子系统动态特性分析

Dynamic characteristics analysis of a wide temperature range ceramic bearing rotor system considering deflection

宽温域下陶瓷轴承外圈与轴承座之间配合间隙发生变化,同时转子质量对轴特别是细长轴会产生挠度影响,导致轴与轴承接触处力的边界条件发生变化,对轴承性能有很大影响。建立一种考虑挠度变化对宽温域内轴承转子系统影响的动力学模型,将轴承座与陶瓷轴承的热变形分别计算,并将不同温度下配合间隙作为边界条件,最后引入挠度因素改变轴与轴承接触处力的边界条件,来对全陶瓷球轴承动态特性进行求解。考虑轴承工作温度以及转轴挠度变化,对全陶瓷球轴承外圈振动情况展开参数化研究,并结合试验手段对模型精度加以验证。结果表明,挠度的产生使宽温域内全陶瓷轴承径向竖直正方向振动幅值减小,导致系统运行不稳定。研究结果对全陶瓷轴承动力学分析提供参考,并为提高陶瓷轴承转子系统稳定性提供理论依据。

For a ceramic bearing rotor system,under a wide temperature range,fit clearance between outer ring of the ceramic bearing and bearing pedestal changes,and rotor mass has a deflection effect on rotating shaft,especially,a slender rotting shaft to cause changes of force boundary conditions at the contact position between shaft and bearing,these changes have large impact on bearing performance.Here,a dynamic model was established considering effects of deflection changes on a ceramic bearing rotor system within a wide temperature range.Thermal deformations of bearing pedestal and ceramic bearing were calculated,respectively,and fit clearances at different temperatures were taken as boundary conditions.Finally,the deflection factor was introduced to vary force boundary conditions at contact position between shaft and bearing,and solve dynamic characteristics of full ceramic ball bearing.Considering changes of bearing operating temperature and shaft deflection,parameterized study was performed for outer ring vibration of full ceramic ball bearing,and the accuracy of the model was verified with experimental means.The results showed that the action of deflection makes radial vibration amplitude in vertical positive direction of full ceramic bearing decrease within a wide temperature range,and causes unstable system operation;the study results can provide a reference for dynamic analysis of full ceramic bearing,and a theoretical basis for improving the stability of ceramic bearing rotor systems.