表面粗糙度特征对齿轮接触区润滑特性的影响

大部分工程实际粗糙表面符合非高斯分布,并对齿轮接触副润滑特性有重要影响.将渐开线齿轮啮合过程中齿面接触等效为三维无限长线接触,建立了一个可分析直齿轮和斜齿轮的混合弹流润滑计算模型;采用基于快速傅里叶变换的数值仿真方法生成给定参数的非高斯粗糙表面;运用该模型对直齿轮和斜齿轮啮合过程进行分析,求得不同表面粗糙度特征齿轮在各个啮合点的油膜厚度、接触区载荷以及接触区比例的情况.结果表明:对于标准差相等的非高斯粗糙表面,偏度值对齿轮润滑状况的影响与工况紧密相关,在润滑良好的条件下,偏度值越小润滑状况越优;润滑恶劣的条件下,偏度值越大润滑状况越优;而在各种工况下,峰度值对齿轮润滑状况的影响都表现出峰度值越大润滑状况越优的特点.

Influence of Surface Roughnesson the Mixed Elastohydrodynamic Lubrication Performance of Gear Contact Area

Most practical engineering rough surfaces approximately follow non-Gaussian distributions. Surface roughness characteristics play an important role in gear lubrication performance. An elastohydrodynamic lubrication (EHL) model for involute gears was developed by simplifying the contact between meshing tooth surfaces of spur or helical gears as a three-dimensional infinite line-contact model. By using the proposed model and non-Gaussian random roughness surfaces generated by numerical method with given parameters based on FFT, the meshing process of spur and helical gears was analyzed. The film thickness, contact area ratio and contact load ratio of contacting points were obtained as well.The results show that a small skewness improved the lubrication state under sufficient oil conditions; instead, while for a oil starvation, the lubrication status became worse when the skewness decreased. However, in all cases, a greater kurtosis provided a better lubrication state.