Tribological behavior of dimples textured rolling element bearings under stepped load and starved lubrication

Purpose The purpose of this paper is to report the tribological behavior of dimples textured rolling element bearings (REBs) under variable load and starved lubrication. Design/methodology/approach The pattern parameters include line-diameter of dimples (200 mu m, 250 mu m, 300 mu m), depth of dimples (10 mu m, 20 mu m, 30 mu m). Dimple patterns were prepared on the raceways of the shaft washers of cylindrical roller thrust bearings (CRTBs). A vertical wear test rig was used to obtain their coefficients of friction (COFs) under stepped load (1200-6000 N, with a manually increase of 1200 N every 3600 s) and starved lubrication. The wear losses and worn surfaces were characterized. The tribological performance between stepped load and fixed load (4000 N) was compared. The influence mechanism of dimples on the friction and wear properties of CRTBs under stepped load and starved lubrication was also discussed. Findings Compared with the data of smooth ones, the average COFs of the dimples textured bearings are almost all reduced under stepped load and starved lubrication, while their mass losses almost all get higher. The depth-diameter ratio and the effective volume coefficient of dimples are the important factors. In this work, compared with the smooth group, when the line-diameter of dimple is 250 mu m and the depth is 20 mu m, i.e. the depth-diameter ratio is 0.08, its average COF is reduced by 46.8% and its mass loss is reduced by about 7%, showing wonderful friction-reducing effect and good wear resistance. Originality/value This work can provide a reference for the raceway design of REBs.