弹流润滑状态下机床主轴轴承刚度特性分析

圆柱滚子轴承的刚度特性会对机床动态性能产生较大影响。在双列圆柱滚子轴承力学分析的基础上,综合赫兹接触与润滑油膜对轴承刚度的影响,分析了不同工况以及润滑参数下的轴承刚度变化特性。分析结果表明,弹流润滑产生的润滑油膜会使轴承综合刚度下降;随着外载荷的增大,赫兹刚度与油膜刚度均有所提升,轴承综合刚度提高;提升轴承预紧量有利于提高轴承综合刚度;随着转速的提升,轴承综合刚度呈下降趋势;润滑油动力黏度以及黏压系数的增大均使得轴承综合刚度下降。

Analysis for Stiffness Characteristic of Machine Tool Spindle Bearing Under Elastohydrodynamic Lubrication Condition

The stiffness characteristics of cylindrical roller bearings will have great impact on the dynamic performance of machine tools.Based on the analysis for the double-row cylindrical roller bearing,considering the influence of the lubricant oil film on the stiffness,the stiffness variation characteristics under different operating conditions and lubrication parameters are analyzed.The analysis results show that the lubricating oil film produced by elastohydrodynamic lubrication will reduce the comprehensive stiffness of the bearing.When the external load increases,the hertz stiffness,the oil film stiffness and the comprehensive stiffness both increase.Increasing the preload value of bearing is conductive to improving the comprehensive stiffness.When the rotation speed increases,the comprehensive stiffness of the bearing shows a downward trend.The increase of the lubricating oil dynamic viscosity coefficient or the pressure viscosity coefficient will both make the comprehensive stiffness of bearing decrease.