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• A tribo-dynamic analysis procedure is developed for the predictions of the aero ball bearing with 3D measured roughness. • The influences of structure parameters and running conditions on the bearing dynamic performance have been discussed. • The roughness effects on lubrication state and friction-temperature of the aero ball bearing are investigated. • The 3D dynamic subsurface stress of the aero ball bearing has been researched. Tribological failures, like wear, scuffing and pitting, etc, often occur in aero ball bearings due to large dry contact area, high friction-flash temperature and stress concentration at the interface between the contacting ball and race. In this paper, a numerical tribo-dynamic analysis procedure is developed for the predictions of dynamic performance, lubrication state, friction-temperature, and subsurface stress of the aero ball bearing with 3D measured roughness. The numerical model is verified by comparing the friction coefficients with the testing results, which show well agreements and proves the presented model is available. The dynamic performance of bearing at different azimuth angle are studied, which indicate the increasing radial load and speed result in more asymmetric distributions of the contact load, stress and slide-roll ratio, the maximum values and the unloaded-region become larger. With the increase of the inner race groove coefficient and the contact angle, the pv value and the radial stiffness decrease clearly. The tribology behaviors of the ball bearing are also investigated, the obtained results indicate that the heavy-load and low-speed lead to large dry contact areas, high friction-temperature, and high local stress peaks, the lubrication state become worse, which may further cause the failures of mass wear, scuffing and micro-pitting. [ABSTRACT FROM AUTHOR]

The timing gears of the ship internal combustion engine usually undergo dynamic loading conditions, and often work in a mixed lubrication state. In this study, by considering the three-dimensional (3D) machined roughness, an integrated model with the analysis of mixed lubrication state and dynamic-meshing performance for the spur gear is developed. The model is verified by comparing its results with the predictions using the typical line-contact EHL formulas. The machined roughness apparently affects the local 3D distributions of the film pressure and thickness. The shaved surfaces have the minimum film thickness ratio and the worst lubrication state, while the polished surfaces can improve the lubrication performance of the timing gear pairs greatly. Under the conditions of heavy-load and low-speed, almost all of the Hertzian contact zone appears to be in contact with 0 film thickness, and the local maximum pressure may lead to serious stress concentration, film breakdown, and excessive wear, etc. By optimizing the gear module and pressure angle, the loading capacity of the timing gear is promoted and the contact area gets reduced, the lubrication state improves significantly from mixed lubrication to full film lubrication. • An integrated model with the mixed lubrication and dynamic-meshing performance for the spur gear is developed. • The mixed lubrication model of the timing gear pairs with 3D real roughness is built. • The effects of machined process on mixed lubrication state of the timing gears have been researched. • The ways to improve lubrication by optimizing the gear modulus and pressure angle are investigated. [ABSTRACT FROM AUTHOR]