Effect of micro grooves on lubrication performance of friction pairs

The influence of micro-groove parameters on the lubrication performance of plane friction pair is studied, by combining theoretical analysis with experiment. The theoretical model of single-groove is established, the variation rules of bearing capacity, maximum pressure and friction coefficient are obtained by changing the number, width and depth of groove. At the same time, micro-grooves with different parameters are processed on the surface of friction pair, the variation rules of the average friction coefficient, friction coefficient under different lubrication conditions are obtained in experiment, and the wear condition of friction pair surface is observed. The results show that the lubrication performance of friction pair increases, with the increase of the micro-groove width. The numerical value of the groove width–depth ratio will influence the friction pair, when the width–depth ratio is greater than or equal to 2.5, the dynamic pressure effect of micro-groove occupies a dominant position, which can improve effectively the lubrication performance. When the width–depth ratio is less than 2.5, the micro-groove will have a negative impact, resulting in the increase of friction coefficient. The groove density will also influence the lubrication performance of friction pair, when the density is less than 10%, the spacing between the micro grooves is too large to collect wear particles, when the density is greater than 20%, the surface roughness of friction pair will be affected, leading to the increase of friction coefficient. The optimal parameters of the micro-groove obtained are as follows: the optimal density is 10%, the width is 0.1–0.2 mm, and the ratio of width to depth is greater than or equal to 2.5. In addition, by comparing the variation of friction coefficient under different lubrication conditions, it can be concluded that adding solid lubricant in lubricating oil, can not only reduce the friction coefficient value, but also decrease the variation fluctuation of friction coefficient.