歪斜安装对组配轴承转子系统动力学特性影响

Influence of Installed Outer Race on Nonlinear Dynamic Characteristics for Matched Bearings-Rotor System

针对多联组配轴承歪斜安装情况,推导了一个轴承外圈发生绕竖直方向歪斜时滚动轴承的非线性支承力形式,并借助Timoshenko梁轴单元建立了主轴模型,利用打靶法和Floquet理论分析了歪斜对系统全局非线性稳定特性和振动特性的影响。通过与正常安装组配轴承转子系统对比发现:外圈歪斜后系统在大间隙时的低转速区域容易出现倍周期分叉,在高转速区域易表现为伪周期分叉;在小间隙工况时容易获得大范围的周期运动参数区域。同时,歪斜使得系统的一临界峰峰值右移且明显放大,从而导致系统在高转速区域的水平方向振动明显增大。研究结果表明,掌握且合理利用轴承歪斜后的非均匀间隙特性,有助于改善系统运行的动力特性。

For a skewing installed matched bearings-rotor system,an expression of the nonlinear supporting force is deduced when the outer race skews around the vertical axis.Timoshenke elements are chosen to model the flexible rotor,and shooting method is used to analyze the global nonlinear dynamic stability and vibration characteristics following Floquet theory.Compared with the normally installed bearing rotor system,the skewing with large internal clearance usually leads to multi-periodic behaviors in low speed region,and quasi-periodic behaviors in high speed region; the stable parameter region is widened for small clearance.The skewing makes vibration peak obviously right shift and magnified,and violent vibration then occurs horizontally in high speed region.