加工中心高速电主轴综合精度分析
Accuracy of an electric spindle

高速电主轴作为加工中心的核心部件，直接影响加工中心的加工精度和工件的表面质量和粗糙度。该文以应用在加工中心上的高速电主轴为研究对象，对电主轴的径向精度、回转倾角、轴向精度进行了分析。基于最小二乘圆近似算法，对电主轴的径向误差运动进行了建模，设计了一种电主轴径向回转精度快速评价方法，建立了倾斜误差运动模型，并给出了电主轴回转轴倾斜角度的计算方法；基于时域和频域信号分析方法，对电主轴轴向运动特征值进行了提取，从而实现电主轴轴向精度的评价。将该综合精度分析方法应用在一种加工中心的高速电主轴上，结果表明：电主轴的径向误差和轴向误差随着转速的升高，先保持不变再升高，回转轴线倾斜角度误差随着转速的升高基本保持不变。该方法可应用在电主轴性能检测和精度衰退试验中。
Abstract：An electric spindle, as the core of a CNC machine center, directly affects the accuracy of the CNC machining center. This paper describes a method to evaluate electric spindle accuracy by analyzing the spindle radial, tilt and axial motion errors. A radial error model of the electric spindle is then developed from the least squares circle. A rapid evaluation method of the radial accuracy uses a least squares circle approximation algorithm. The radial error is then used to calculate the tilt error and the tilt angle of the spindle rotation axis. Time and frequency domain signal analyses are used to extract the eigenvalues of the axial error to evaluate the axial positioning accuracy of the spindle. This comprehensive accuracy analysis method was applied to a high-speed electric spindle with the results showing that with as the rotational speed increased, the radial error increased while the tilt error and the axial error remained constant. This accuracy analysis method can be applied to analyzed the performance and accuracy degradation of spindles.