高速主轴不平衡振动行为分析与抑制策略

Behavior Analysis and Suppression Strategy for Unbalanced Vibration in High-Speed Spindle System

针对高速主轴不平衡激励下空间振动问题,构建了多自由度高速主轴有限元分析模型。基于Matlab解析获得主轴模态特性信息,进而通过与Ansys分析结果对比,可知两者所求解得到的主轴弯曲振型整体形貌变化规律相同,幅频响应曲线峰值契合度较高。为进一步验证模型的有效性,通过高速主轴系统模态测试获取了主轴实验频率响应函数,实验结果表明,其与基于动力学模型分析得到的前三阶谐振频率误差分别为0.16%、4.38%、5.95%,两者匹配程度较高,该模型能准确描述主轴的动态特性。基于该模型,分析了不平衡激励作用下主轴不同位置节点的空间位移特征,研究了主轴转子在不同大小不平衡激励下的空间响应特性,并总结得出了振型及激励对空间位移的影响规律。最后,提出了基于动力学模型的不平衡振动抑制策略,并在9 000 r/min时进行了高速主轴动平衡实验,结果表明:该策略无需添加试重,仅在低于临界转速下采集振动数据就可识别不平衡量,添加配重后不平衡振动得到有效抑制。

To suppress the unbalanced spatial vibration in a high-speed spindle system, a five-degree-of-freedom finite element model of the high-speed spindle was built and the comparison of the modal characteristic information of the spindle obtained by Matlab and Ansys was made. Simulation results indicate that the changing rules of the bending shapes and the peak values of the amplitude-frequency response are the same. Then, to further verify the validity of the proposed model, the experimental frequency response function of the high-speed spindle was obtained through modal test, and the results show that the difference between the measured first three-order critical frequency and the simulated result obtained by the dynamic model is 0.16%, 4.38%, and 5.95%, respectively, which means the proposed model can accurately describe the dynamic characteristics of the spindle. Based on this model, the spatial vibration characteristics at different nodes of the spindle under various unbalanced excitations were analyzed, and the influences of mode shapes and unbalanced excitations were summarized. Finally, an unbalanced vibration suppression strategy based on the model was proposed and the experimental analysis on a high-speed spindle system was performed at 9 000 r/min. Experimental results show that the strategy can identify the unbalanced vectors without trial weights, it only needs to collect the vibration information below the first-order critical speed, and the unbalanced vibration can be effectively suppressed after adding counter weights.