内外环对高速球轴承中球体拖曳阻力系数的影响

Effects of Inner and Outer Rings on Drag Coefficient of Spheres in High-Speed Ball Bearings

关键词:  球轴承  拖曳阻力  球体绕流  内外环  压力分布

Key words:  Ball bearing  Drag force  Flow around sphere  Inner and outer rings  Pressure distribution

摘要:

在液体润滑的高速球轴承中，球体公转运动会受到润滑流体的拖曳阻力，对球轴承的动力及产热等性能造成显著影响。针对球轴承中球形滚动体公转的流体拖曳阻力问题，建立平板夹层单球体绕流模型，通过数值模拟和实验研究的方法，研究内外环对球体绕流的流动特征及压力分布的影响，分析单球体绕流的拖曳阻力系数变化规律，并与开放空间球绕流模型进行对比。研究表明，建立的数值计算方法和实验结果吻合良好，误差不超过10%。在相同雷诺数下，由于内外壁面的限流作用，球体与壁面接触区域压差阻力明显增大，导致夹层空间球绕流中球体拖曳阻力系数明显高于开放空间球绕流，在10³<Re<10⁵内约为开放空间球体阻力系数的两倍。

Abstract:

In high speed oil-lubricated ball bearings， rolling elements are resisted by lubricating fluid， changing the bearing’s dynamic and thermal behaviour. In order to investigate the effects of inner and outer rings on the ball’s drag coefficient， a numerical simulation model and an experimental device are developed with one single sphere confined by two flat walls. The changing rule of drag coefficient is summarized and compared with that of one sphere in open space. Results show that the numerical model is reliable with an error of less than 10% compared with the experiment. For the same Reynolds number， the pressure difference between the upstream and downstream of the sphere is enlarged obviously with the restriction of two walls， rising the drag coefficient to a high level. It’s illustrated that drag coefficient on sphere in restricted space is about two times to that of sphere in open space in the range of 10³<Re<10⁵.