推力滑动轴承表面织构的优化设计

在推力滑动轴承表面设计轴对称分布的扇形直槽织构,以提高轴承的流体动压润滑性能。为对扇形直槽的参数(直槽的数目、深度和面积比)进行优化设计,将轴承的内外径、转速、润滑油黏度、轴承间隙以及直槽参数作为变量,求解不同变量值下的Reynolds方程,得到油膜承载力,运用最小二乘法对承载力的离散数据进行拟合,得到承载力的拟合函数,并推导出摩擦因数的表达式。针对"轴承间隙已知,要求承载力最大或者摩擦因数最小,以及承载力已知,要求轴承间隙最大或者摩擦因数最小"这四种约束条件及优化目标,利用承载力和摩擦因数的拟合公式,得到对应的直槽参数的最优值。通过数值试验,将拟合公式计算的承载力、轴承间隙和摩擦因数与直接求解Reynolds方程得到的结果进行对比,验证了直槽参数优化结果的正确性。设计加工三种具有不同直槽数目和深度的扇形直槽织构并进行摩擦试验,通过对比摩擦因数的计算值和试验值后发现,承载力和摩擦因数的拟合公式在趋势上是正确的,直槽参数的优化结果是可信的。

Optimal Design of Surface Texture in Parallel Thrust Bearings

Surface textures of fan-shaped grooves of axisymmetrical distribution are designed on one of the parallel thrust bearing surfaces to improve the hydrodynamic lubrication performance of the bearing.In order to optimize the groove parameters(including the groove number,depth and area ratio),a regressive formula of the bearing load carrying capacity is obtained,based on the calculation results of the load carrying capacity by solving Reynolds equation under various combinations of bearing inner and outer diameters,rotation speed,lubricant viscosity,bearing clearance as well as the groove parameters.A formula of the bearing friction coefficient is derived using the regressive formula of the load carrying capacity.Based on these formulae,the optimal groove parameters are found under the four different kinds of constraints and optimization goals: Given the bearing clearance,requiring the maximal load carrying capacity or minimal friction coefficient;given the load carrying capacity,requiring the maximal bearing clearance or minimal friction coefficient.Furthermore,the validity of the optimal design is confirmed by comparing the load carrying capacity,bearing clearance and friction coefficient calculated by the regressive formulae with the full simulation results of Reynolds equation.Friction experiments are carried out on three surface textures of fan-shaped grooves with different groove numbers and depths.It is found that the trend of the calculated friction coefficient is the same as that of the experimental one,and the optimal results of the groove parameters are credible.