加工误差对陀螺电机用动压气体轴承刚度的影响

Influence of machining errors on stiffness of hydrodynamic gas bearing in gyroscope motor

为了进一步提高精密H型动压气体轴承的刚度性能,着重分析了轴承加工误差对轴承刚度的影响。首先,通过在轴承内部交界处引入压力和流量连续方程,建立可考虑径向、止推轴承相互作用的H 型动压气体轴承模型;然后,采用有限单元法进行求解以得到轴承压力分布及刚度等特性;最后,在对模型和计算结果进行实验验证后,对不同加工误差下的轴承刚度进行了研究。分析结果显示,加工误差对轴承刚度影响由强到弱的顺序为轴承间隙、止推板平面度、径向轴承锥度、圆度和止推板垂直度误差,0.2μm 的轴承间隙加工误差可使轴承刚度降低20%~25%,而垂直度误差对轴承刚度的影响不大。研究结果为H 型动压气体轴承的结构设计和性能提高提供了有益的参考。

To improve the stiffness characteristics of H-type hydrodynamic gas bearing, the influences of machining errors on the bearing stiffness are analyzed. First, a theoretical model considering the interaction of journal and thrust bearing is built by introducing the pressure and flow continuity equations at the boundaries of the bearings. Then, the finite element method is adopted to achieve the pressure distribution and stiffness of the H-type bearing. Finally, the stiffness characteristics of the bearing with machining errors are investigated based on the experiment verification of the numerical model and the calculation results. The analysis results show that the influence factors of machining error on bearing stiffness are bearing clearance, flatness, taper, roundness, and verticality error, successively from strong to weak. For instance, a clearance error of 0.2 μm would reduce the bearing’s stiffness by 20%~25%, while the influence of verticality error of thrust bearing is close to zero. These investigation and analysis results could provide valuable information for the structure design and performance improvement of H-type hydrodynamic gas bearing.