加工中心电主轴复合“转子—轴承”系统动态特性研究

Investigation into the Dynamic Characteristics of Combined “Shaft-Bearing” System of Machining Center Motorized Spindle

针对加工中心电主轴的结构特点和装配流程,研究了复合"转子—轴承"系统在约束边界下的动态特性和测试技术,并基于主轴端原点传递函数对比分析了有限元分析结果与约束模态测试结果。结果表明:所建立的分析模型和测试平台方法可行,能准确反映主轴在联机后的动态特性;分析模型和实验所测转子一弯、转子二弯分别对应的固有频率吻合程度较高,误差为0.57%左右;分析模型和实验所测主轴端原点传函曲线走势基本一致,吻合度高。建立的模型和测试平台能有效预测加工中心电主轴在与机床联机后的动态特性,为该系列电主轴的进一步智能优化设计和系统振动故障分析诊断与预报提供依据。

Online dynamic characteristics of motorized spindle, an crucial functional component of a machine tool, vary due to the change of its boundary conditions. Therefore, the investigation of dynamic characteristics of motorized spindle is of more significance in engineering domain. In this paper, the dynamic characteristics of combined＂ Shaft-Bearing＂ system are studied with the constrained boundary condition theoretically and experimentally, which aims at investigating both the influence of motorized spindle structural char- acteristics and its assemble procedure. The transfer function of spindle nose calculated by finite element method is verified by constrain- ed experimental modal analysis. It is shown： the analysis model and the experimental platform constructed in this paper are reliable, which can reflect the online motorized spindle dynamic characteristics accurately. The frequencies of first bend mode, obtained by anal- ysis model and experimentation respectively, exactly coincided with each other, and so are the frequencies of second bend mode. The relative error is around 0.57%. The transfer function curve obtained by analysis model and experimentation coincide with each other. The model, as well as the test platform, constructed in this paper can effectively predict the online dynamic characteristics of machining center motorized spindle, which can be regarded as the basis for both further artificial optimization design of motorized spindle and sys- tem vibration error analysis-diagnosis-prediction.