Conjugate approach for hypoid gears frictional loss comparison between different roughness patterns under mixed elastohydrodynamic lubrication regime

This paper compares the frictional loss of hypoid gears between three different tooth surface roughness patterns under the mixed elastohydrodynamic lubrication regime, namely the striated, the isotropic and the less roughed. Conjugate approach contact model for such purpose is proposed, which aids in determination of the parameters input for the lubrication model and construction of wanted tooth surface roughness patterns, by integrating the digital tooth surface technique, the conjugate approach teeth contact analysis and a particular contact search algorithm into a fully integrated contact model. The frictional losses are computed from the upper to the down boundary defined by the load share portion between the film and the asperity in the regime with the varying lambda ratio by continuously adding the rotational speed on the geared system. The simulation finds that the frictional loss of the case striated is less than the case isotropic, and the case less roughed has the smallest frictional loss. It also finds that the rotational speed has a significant influence on the film thickness, on the load share, and thus on the frictional loss. Merits are exhibited with this integrated contact model, including good compatibility with lubrication model in passing data, good accuracy and less computation time.