Friction Coefficient and Mesh Efficiency in Spiral Bevel Gears

The friction coefficient and mesh efficiency were investigated under different contact positions and speeds considering the contact geometry, contact load, velocity vector, entraining angle, surface roughness, rheological characteristic. The results indicate that the friction coefficient increased firstly and then decreased which gave a reverse trend compared with the variation of relative sliding velocity during a meshing cycle. Besides. from the engaging-in position to engaging-out position, the mesh efficiency appeared a similar trend as friction; however, the efficiency increased again around engaging-out position due to the start of another meshing pair. The larger gear rotational speed, the smaller friction coefficient and the higher efficiency were. The friction coefficient and meshing efficiency were also analyzed using the friction computational methods in literature, and the results were compared with the present study. The analysis reveals that the error of friction was relatively large nearby the pith point whilst the error of efficiency was negligible. The efficiency obtained by simplified method seemed to be closed to the present study under mixed lubrication and full-film lubrication regimes.