The double-row ball slewing bearing The double-row ball slewing bearing has three races. The balls and cages can be directly aligned into the upper or lower raceway. According to force situation, the arrangement is two rows of different diameter balls. This kind of openly assembling is very handy. The loading angles of upper and lower raceways both are 90o. It can take large axial force, and overturning moment. When the radial force is larger than 0.1 times the axial force, its raceway must be designed specially. The double-row ball slewing bearing features bigger axial and radial dimensions, and stable structure. It is especially used for tower cranes with mid-diameter or bigger, and truck-mounted cranes etc loading machinery.