Lubrication performance of conical spiral-groove bearings with rough surfaces

A mixed lubrication model of conical spiral-groove bearings is established by integrating partial fluid lubrication theory and G-W statistical theory. Considering the effect of bearing surface roughness, the equivalent average Reynolds equation is derived based on average flow model, which is solved by boundary fitted coordinate system and finite difference method. The G-W contact model is used to calculate the axial force and friction force produced by the contact of multi asperities. The coefficients of friction are calculated and measured under different rotational speed and the theoretical results are in accordance with the test results. The results show that comparing with bearings with deep groove, ones with shallower groove have lower transition speed and lower friction coefficient at low speeds.