Abstract:

The modeling method of the machine tool spindle system is mostly beam and pipe element modeling. The system joint surface has two parts: The spindle and the tool holder, and the tool holder and the tool. These joint surfaces are mostly simulated by rigid connection or custom stiffness matrix. The system can also be modeled in the form of solid elements, while establishing contact pairs at the contact locations. In this paper, beam elements and solid elements were used to model the spindle system of a vertical machining center. Through the calculation results, the effects on modeling in different element types on the natural frequency of the system and the frequency response function of the tool nose point were compared and analyzed. The results show that the natural frequency value of solid element modeling is larger than that of beam element modeling, and the mode shapes are more abundant. With the increase of the excitation frequency, the amplitude?frequency response curve in the solid element modeling mode oscillates more violently, indicating that more excitation frequency values can be captured in this mode. The research results can provide theoretical reference for the dynamic characteristics of the spindle system for scientific research.

Key words: Spindle?tool Coupling system, Solid elements, Beam elements, Contact pairs, Dynamic properties

摘要：

机床主轴系统的建模方式多为梁、管单元建模，系统结合面有主轴?刀柄、刀柄?刀具两部分，这些结合面多采用刚性连接或自定义刚度矩阵的方法进行模拟，主轴系统也可以采用实体单元的方式进行建模，同时在接触位置建立接触对。采用梁单元、实体单元对某立式加工中心主轴系统建模，通过计算结果，分析了不同单元类型建模对系统固有频率及刀尖点频响函数的影响。结果表明，实体单元建模的固有频率大于梁单元建模的固有频率，且振型更为丰富；随着激振频率的增大，实体单元建模方式下的幅频响应曲线震荡更加剧烈，说明该方式可以捕捉更多的激振频率。研究结果可为科学研究主轴系统的动力学特性提供理论参考。

关键词: 主轴?刀具耦合系统, 实体单元, 梁单元, 接触对, 动力学特性