一种锂基高速轴承润滑脂的弹流拖动及流变特性研究

通过模拟滚动轴承的实际工况,得到一种锂基高速轴承润滑脂在不同工况下的弹流拖动系数,给出该脂拖动系数的数学模型,并对其流变特性进行分析,建立流变模型。结果表明:当载荷相同,速度由20 m/s增加到40 m/s时,拖动系数逐渐变小。当速度相同,载荷由20 N上升到135 N时,拖动系数增加至某一最大值之后减小。拖动力受润滑膜厚、滑滚比、平均极限剪切应力、接触圆半径和平均剪切模量的影响。润滑脂的平均极限剪切应力和速度呈显著的负相关关系,且和载荷呈正相关关系;润滑脂的平均剪切弹性模量与速度呈负相关关系。载荷超过转折载荷之前,润滑脂的平均剪切弹性模量与载荷呈正相关关系;载荷超过转折载荷之后,润滑脂的平均剪切弹性模量与载荷呈负相关关系。

Study on elastohydrodynamic traction and rheological characteristics of lithium grease used at high speed bearing

Through the simulation of a rolling bearing in its actual working condition, the elastohydrodynamic traction coefficients of a lithium grease used at a high speed bearing were measured under different conditions on a traction test rig, and the traction coefficient calculation model was given. The rheological characteristics of this grease were analyzed, and its rheological model was given. The results show that the traction coefficients decrease with the increase of speed from 20m/s to 40m/s for a constant normal load. Traction coefficients first increase to a maximum value and then decrease with the increase of normal load from 20N to 135N at a constant speed. Traction force is determined by the grease thickness, slid-to-roll ratio, contact radius, average shear stress and average shear modulus. Average shear stress has a negative correlation with the speed and has a positive correlation with the normal load. Average shear modulus has a negative correlation with the speed. When the normal load is lower than the critical load, the average shear modulus has a positive correlation with the normal load. And when the normal load is higher than the critical load, the average shear modulus has a negative correlation with the normal load.