转动与摆动复合运动下脂润滑关节轴承的数值分析

建立了球面轴承的三维润滑模型，该模型将内圈的转动运动、轴颈倾斜引起的内圈倾斜和内圈的摆动运动等因素纳入考虑，推导出球坐标下适用于非Newton(牛顿)流体润滑的Reynolds(雷诺)方程.应用该模型，并考虑使用润滑脂的Ostwald流变模型，对向心关节轴承的润滑问题进行了数值计算，研究了在不同的幂律指数、内圈倾斜角度和摆动角速度下，脂润滑膜的压力分布、最大压力、承载力和流量.结果表明:在合适的操作条件下，脂润滑能产生明显的流体动压效应；在其它参数不变时，幂律指数对脂润滑膜的最大压力和承载能力影响显著，相对于Newton流体，剪切稠化流体可提高润滑膜的最大压力和承载能力，并增加周向流量，而剪切稀化流体的影响效果则相反；内圈倾斜角度对脂润滑膜最大压力和承载能力的影响较小，内圈摆动角速度的影响则较为明显.

Numerical Analysis of Grease Lubrication for Radial Spherical Plain Bearings in Rotation and Swing Motion

Formulation of the 3D lubrication model for spherical bearings was proposed. The rotation of the inner ring, the inner ring tilt caused by the axle journal misalignment and the swing angular velocity of the inner ring were taken into account in this model, and the modified Reynolds equation in the spherical coordinate system was obtained to depict non-Newtonian fluid lubrication. Moreover, with the lubrication model aforementioned, the lubrication problems of radial spherical plain bearings were analysed numerically based on the Ostwald rheological model for greases. The pressure distribution, the maximum pressure, the load capacity and the flow rate of the grease lubricant film were studied with variations of the grease power-law index, the inner ring inclination angle and the swing angular velocity, respectively. It is found that the grease lubricant film generates obvious hydrodynamic effects. With the other parameters fixed, the power-law index has significant influences on the maximum pressure and the load capacity of the grease film. Compared with Newtonian fluid, the shear-thickening fluid is observed to increase the values of film maximum pressure, load capacity and axial flow rate, but the shear-thinning fluid is observed to act contrarily. The inner ring inclination angle has little effect on the maximum pressure and the load capacity, while the swing angular velocity has much.