电主轴的动态特性在很大程度上决定数控机床的加工精度和生产效率。为克服传统方法在预测主轴／轴承单元设计合理性方面的弱点，本文借助ANSYS软件对某高速卧式加工中心的电主轴进行动力学特性研究。结果表明：该电主轴的设计转速远低于其低阶模态固有频率659.90 Hz所对应的临界转速，因此能够有效避免共振；如果主轴系统因受到周期性激振力作用而产生共振，则轴承3支撑处的应力强度最大，容易出现因振动烈度过大而导致轴承工作精度丧失甚至损坏失效。

The machining precision and cutting efficiency of a numerical control machine tool to a great extent depend on the dynamic characteristics of the motorized spindle. To overcome the weakness of predicting the rationality of axis-bearing unit designed by traditional method, the dynamic characteristics of the motorized spindle installed in a certain high-speed horizontal machining center were studied in this paper. The results showed that the rotary speed designed was far lower than the critical rotary speed which matched with the low-order modal inherence frequency (659.90 Hz) of the spindle, so resonance vibration could be effectively avoided. If the spindle unit generated resonance vibration under the action of a periodic exciting forces, the stress of bearing 3 would reach the maximal value, and the huge vibration intensity would result in the loss of bearing working precision and even destroy the bearing.