Slewing bearings can carry heavier axial load radial loads titling moment and combined loads. Slewing bearing is a kind of large-size bearing with special structure and performance such as propping rotating transmission and fixing etc. Generally slewing bearings have mounting holes oil holes and sealing equipments. Slewing bearings can meet different needs of various main engines in different working conditions. On the other hand the structure of slewing bearing is compact which make it easy to rotate mount and maintain. Slewing bearings are widely used in cranes transportation excavators building engine port machineries wind turbine medical facilities radar missile launcher etc. and those large-size slewing equipments.