加工误差和形位误差对气浮主轴稳定性的影响

Effects of Manufacturing Errors and Journal Misalignment on the Stability of Aerostatic Spindle

采用有限差分结合线性小扰动法研究静压气浮主轴加工误差(正弦波纹、矩形波纹、三角波纹)和形位误差对主轴临界惯性力和临界涡动比的影响。结果表明:随着偏心率增加,临界惯性力增大而临界涡动比减小;转速增大,临界惯性力增大,临界涡动比增大到极值后略微减小,小偏心率和高转速有利于提高主轴稳定性;正弦波纹提高主轴稳定性最显著,矩形波纹次之,三角波纹导致主轴稳定性降低;加工误差周期越小,主轴稳定性越好;误差周期较大时,波纹幅值增大,主轴稳定性下降;误差周期较小时,波纹幅值对主轴稳定性的影响可以忽略不计;形位误差导致主轴稳定性降低,x、y方向同时存在形位误差对主轴稳定性的影响大于x或y单一方向形位误差。

The finite difference method combination linear perturbation method was used to analyze the effect of manufacturing errors(sine waviness,square waviness,triangular waviness)and journal misalignment on critical inertia force and critical whirl ratio of hydrostatic pressure aerostatic spindle.The results indicate that the critical inertia force increases while the critical whirl ratio decreases with the growth of eccentricity ratio.Moreover,the higher the rotation speed is,the larger the critical inertia force is.However,the critical whirl ratio increases first and then decreases slightly with the growth of rotation speed.Small eccentricity ratio and high rotation speed are helpful for improving the stability of aerostatic spindle.Sine waviness improves the critical whirl ratio most obviously,followed by square waviness and triangular waviness.Furthermore,the smaller the period of manufacturing errors is,the better the stability of the spindle is.The stability of aerostatic spindle degrades with the increases of the waviness amplitude while the effects of waviness amplitude on spindle stability can be neglected if errors with small period.The journal misalignment abates the spindle stability.The effect of misalignment in the x and y directions simultaneously on the stability are greater than it in the x or y direction.