Abstract:The kinematic model of rib roller end in the tapered roller bearings was establish based on the kinematics principle of tapered roller bearings.The rotational angular velocity,revolutionary angular velocity of the tapered roller and distribution of entrainment velocity of the contact region in rib roller end were calculated.The EHL model of rib roller end was establish,and the effect of curvature radius of tapered roller spherical end on film thickness and friction coefficient was discussed under different load and entrainment speed.The effect laws of load and speed on optimal curvature radius of tapered roller spherical end was summarized.That is,when other conditions are equal,the greater the tapered roller end carries,the larger the optimal curvature radius is;the faster the speed is,the smaller the optimal curvature radius is.