Abstract: For the problem of unbalance loading effect and edge loading effect of the contact stress distributions between the rollers and the raceway of crossed cylindrical roller slewing bearing under combined loads, the effective method for improving the roller and raceway contact state is put forward. This method is realized through the profile modification design of rollers under the premise of reasonable bearing clearance. The whole mechanical system of the bearing is modeled and solved, and the effect of the bearing clearance on the unbalance loading of the roller is researched by using the finite length line contact theory. Under the reasonable bearing clearance, the contact stress distributions between the rollers with different crowning values and the raceway are researched. The results show that the contact stress distribution of the roller appears asymmetric along the contact line after the roller suffers unbalanced load, the stress on the heavy end increases while on the light end decreases, and this trend tends to be more significant with the increase of the bearing clearance value. The unbalance loading effect can be improved and the edge loading effect can be eliminated by proper profile modification of the roller. The larger the crowning value of the roller, the more significant effect gets, but there exists the trend of the load concentrating to the central section of the roller. On the basis of considering these influence, the best profile modification parameters of the roller is determined for the crossed cylindrical roller slewing bearing under combined loads.

Key words: clearance, crossed roller, edge loading effect, roller profile modification, slewing bearing, unbalance loading effect