Analysis of running-in process under lubricated conditions using combined time-space plot and three-dimensional rearing curves

The running-in process under the mixed lubrication regime has been analyzed by means of combined time-space plot and three-dimensional bearing curves. The rest was conducted by using vane-an-disc configuration with a disc tha t had unidirectional grinding marks on the surface. The combined time-space plot revealed that the friction force on the transverse roughness is lower than that on the longitudinal roughness in the transition zone between the boundary and mixed lubrication regime. It was also found that as running-i n proceeds, the friction force is reduced in the transverse and longitudina l directions but the discrepancy in the friction force between the two dire ctions increases. The wear volume evaluated by the three-dimensional bearin g curves indicated that the running-in process can be divided into the loca l peak wear stage and the oil film thickness control stage.