Abstract: Considering couple stress effect of lubricant additives, the misaligned bearing is used as the research object, and the mixed thermo-hydrodynamic lubrication model of dynamically loaded bearing is established to explore the coupling effects of misalignment angle, surface roughness and couple stress effect on the lubrication performance and lubrication state. The results show that couple stress effect weakens the phenomenon of increasing the maximum oil film pressure of bearing lubricated with thermal fluid, and the decrease of the maximum oil film pressure gradually increases with the increase of the couple stress effect; compared with the Newtonian fluid, oil film temperature of the bearing with couple stress lubricants decreases, the oil film area in the high temperature area decreases, and the oil film temperature near the journal decreases; increasing the misalignment angle, the maximum oil film temperature inside the fluid increases; with the enhancement of the couple stress effect, the influence of the misalignment angle on the maximum oil film temperature and the value of the nodal couple stress parameter gradually decreases; when the couple stress parameter is small, increasing the surface roughness, the critical speed of the transition between mixed lubrication and hydrodynamic lubrication state increases, and the corresponding minimum friction coefficient increases, and the corresponding minimum friction coefficient increases with the increase of surface roughness.

Key words: couple stress effect, thermal effect, mixed lubrication, misalignment angle