Four-point contact ball slewing bearing is mainly composed of inner ring, outer ring, single-row steel balls, cage (or spacer), sealing device and other parts. The inner ring and outer ring of the four-point contact ball slewing bearing have integral and split structures. The rigidity of the integral ferrule is relatively strong, and the split type is easy to adjust. The split structure has used bolts to connect the two split rings before the product leaves the factory. Four-point contact ball slewing bearings generally have cages (or spacers). The full-filled ball structure is only used when the load is relatively large. The full-filled four-point contact ball bearing has a large bearing capacity, but a large frictional resistance. Friction can also easily cause scratches on the surface layer of the steel ball. The basic structure of the four-point contact ball slewing bearing/slewing ring: with or without gears, external gears and internal gears, with high static load capacity.