three row roller slewing bearing has three seat rings,which separate the upper,lower and radial raceways, it made each row of the roller's load capacity can be specified and can bear different loads simultaneously. The capacity load is the largest one compare with the other three models.Due to the large size in axial and radial dimension the solid structure, it is specially suitable for the heavy duty machinery such as wheeled excavator,wheeled crane, ship crane,ladle turrets and the heavy duty mobile crane etc.