考虑结合面和轴向力的主轴系统动力学特性

汽车覆盖件淬硬钢模具由于硬度高，在铣削过程中动态铣削力大，易发生颤振，而主轴系统动力学特性直接影响铣削稳定性。为了准确建立主轴系统动力学模型，考虑主轴系统铣削状态下产生的轴向铣削力和离心力对主轴结合面接触刚度的影响。通过分析得到，轴向铣削力对主轴结合面接触刚度有强化作用，使主轴系统固有频率有微小的增加；而离心力对结合面接触刚度有软化作用，随着主轴转速升高，系统的固有频率减小，尤其高转速时主轴系统的动力学特性偏差较大，对比而言离心力的软化作用多于轴向铣削力的强化作用，故主轴系统在铣削过程中动力学特性相比静止无载状态下仍是软化现象；分析结合面预紧力、刀具参数等因素对主轴系统动力学特性的影响规律，为准确分析主轴系统动力学特性和预测铣削稳定性提供理论参考。

Dynamics Characteristics of the Spindle System with the Interface and Axial Milling Force

In the process of milling the hardened steel mould of automotive covering parts, the dynamic milling force is larger than others and chattering dither always happens due to its high hardness. Considering the impact of the axial milling force and the centrifugal force which generated by milling spindle system on the interface stiffness of the spindle is in order to bulid accuracy spindle system dynamics model. According to the analysis, the axial milling force has strengthening effect on the interface stiffness of main shaft and the inherent frequency of the main shaft system increases slightly. However, the centrifugal force will soften the interface stiffness. With the increasing spindle speed, the natural frequencies of the system decrease; especially with high speed, the dynamic characteristic of spindle system has a greater deflection. In comparison, softening action of centrifugal force has a more significant influence than the strengthening action of the axial milling force. Therefore, the dynamic characteristics of the main shaft system is still softening during the process of milling than that in static no-load condition. Analysis the impact law of pre-tightening force for interface, cutting tool parameters on spindle system dynamics characteristics to provide the theoretical reference to predict the milling stability for the accurate analysis of the spindle system dynamic characteristic.