计及轴受载变形的粗糙表面轴承热弹性流体动力润滑分析

Thermoelastohydrodynamic Lubrication Analysis of Bearing Considering Shaft Deformation and Surface Roughness

同时计及表面形貌、热效应和轴承表面(热和弹性)变形等,对轴受到载荷作用产生变形,导致轴颈在轴承中倾斜时滑动轴承的热弹性流体动力润滑性能进行研究,主要分析讨论表面热变形等对粗糙表面倾斜轴颈轴承热弹性流体动力润滑性能的影响。计算中,采用基于平均流量模型的广义Reynolds方程进行轴承的润滑分析,采用变形矩阵方法计算轴承表面(热和弹性)变形,采用能量方程和热传导方程计算润滑油和轴承的温度分布。结果表明,计及表面热变形时,半径间隙对轴承最大油膜压力、最小油膜厚度、油膜压力和油膜厚度的分布有较大影响;轴承载荷越大,表面热变形对轴承性能的影响越显著;表面热变形对轴承性能的影响程度与转速高低有直接关系,转速越高,表面热变形的影响越大;相比于表面弹性变形,表面热变形对轴承性能的影响较大;表面形貌是否影响轴承性能以及影响程度与轴承表面变形情况有较大关系,仅考虑热变形时,表面形貌有一定影响,同时考虑热变形和弹性变形时,表面形貌的影响非常小。

The thermoelastrohydrodynamic lubrication properties of bearing with journal misalignment caused by shaft deformation under load considering surface morphology, thermal effect and bearing surface deformation are studied. The effect of thermal deformation of bearing surface on the thermoelastrohydrodynamic lubrication of misaligned bearing with surface roughness is discussed mainly. The lubrication of bearing is analyzed by using average flow model based generalized Reynolds equation. The deformation of bearing surface under pressure or heat of oil film is calculated by deformation matrix method. The temperature distributions of oil and bearing are calculated by energy equation and heat conduction equation. The results show that there is relatively great effect of radial clearance on the maximum film pressure, minimum film thickness, distribution of film pressure and thickness when thermal deformation of bearing surface is considered. The larger the load of bearing is, the more remarkable the effect of thermal deformation on the bearing performance will be. The rotational speed has direct relationship with the affecting degree of thermal deformation on the bearing performance. The higher the speed is, the greater the effect of thermal deformation will be. Compared with elastic deformation, the thermal deformation has greater effect on the bearing performance. The surface morphology has certain effect on the bearing performance when only thermal deformation is considered, but the effect becomes very small when thermal deformation and elastic deformation are considered simultaneously.