混合预紧下高速电主轴涡动频率的理论研究

摘要

为了有效预测并控制高速电主轴的支撑刚度和临界转速，建立了角接触球轴承在混合预紧机理下的数值计算模型，对主轴系统进行有限元建模，耦合轴承组模型与转轴模型构成转轴-轴承模型。通过对整体模型计算获得主轴系统的动态特性参数，将结果反代入整体模型，进而进行循环迭代，从而研究主轴涡动频率。制定转轴-轴承模型动力学计算流程，研究了电主轴在不同工况下轴承支撑刚度和涡动频率等动态特性。理论计算结果表明：与传统计算方法相比，所建模型计算电主轴在高速运转时的动态特性具有更高精度。采用合理的预紧方式和预紧力有利于提高主轴系统在高速运转时的临界频率。%To control and accurately calculate support stiffness and critical speed, numerical calculation models have been established, which considered the mixed preload mechanism of angular contact ball bearing. Taking a spindle system as finite element model, bearing group model and shaft model were coupled to structure the shaft-bearing model. The coupled model was iterated to obtain spindle system dynamic parameters, and then the whirl frequency of spindle was analyzed. The shaft-bearing model dynamics calculation process was set up, and the support stiffness and whirl frequency of spindle was researched in different preload mechanism. Theoretical calculation results show that compared with the traditional method, this model has higher precision to predict high speed spindle dynamic characteristics in operation. Adopting reasonable preload method and selecting proper preload force is conducive to improve the critical frequency of spindle system in operation.