基于模糊理论的立式磁轴承系统保护轴承抗冲击影响因素分析

Analysis on Factors Influencing Impact Resistance of Touchdown Bearings for Vertical Magnetic Levitation System Based on Fuzzy Theory

为分析立式磁轴承失效后保护轴承受转子冲击的影响因素及其影响程度,仿真立式磁轴承系统中转子跌落至保护轴承的动力学过程,建立Ⅰ-Ⅱ级模糊综合评价模型对保护轴承所受轴向碰撞力各影响参数的影响程度进行评判,并利用熵权法、灰色关联度法对模型进行验证,结果表明:随着转子质量、轴向保护间隙、转子偏心角度增大以及有保持架更换为无保持架,保护轴承内圈所受最大轴向碰撞力增大,随着填球数增大,最大轴向碰撞力先减小后增大,而转子转速、滚动体材料、径向保护间隙的变化对轴向碰撞力的影响不大;各参数的影响程度从大到小为转子质量、保护轴承填球数、轴向保护间隙、转子偏心角度、保护轴承有无保持架、滚动体材料、转子转速、径向保护间隙;模糊综合评价模型与熵权法、灰色关联度法的评价结果基本一致,验证了在乏信息条件下利用模糊综合评价模型评价各参数对保护轴承所受轴向碰撞力的影响程度的有效性。

In order to analyze the influencing factors and degree of impact of rotor on touchdown bearings after failure of vertical magnetic bearings,the dynamic process of rotor dropping to touchdown bearings in vertical magnetic levitation system is simulated.A Ⅰ-Ⅱ level fuzzy comprehensive evaluation model is established to evaluate the influence degree of various influencing parameters of axial impact force on touchdown bearings.The entropy weight method and grey correlation degree method are used to verify the model.The results show that with the increase of rotor mass,axial protection clearance,rotor eccentricity angle and replacement of cage with no cage,the maximum axial impact force on inner rings of touchdown bearings increases,with the increase of ball filling number,the maximum axial impact force decreases first and then increases,but the changes in rotor speed,rolling element material and radial protection clearance have little effect on axial impact force;the influence degree of each parameter,from high to low,includes rotor mass,ball filling number of touchdown bearings,axial protection clearance,rotor eccentricity angle,presence or absence of cage,rolling element material,rotor speed and radial protection clearance;the evaluation results of fuzzy comprehensive evaluation model are basically consistent with those of entropy weight method and grey correlation degree method,which verifies the effectiveness of fuzzy comprehensive evaluation model in evaluating the influence degree of various parameters on axial impact force of touchdown bearings under condition of lack of information.