Slewing bearing is large turntable bearing which can accommodate a combined load, i.e. axial, radial loads and tilting moment. These slewing rings are usually provided with holes for fixing bolts; slew bearing seals, internal, external or no gear; lubication holes and seals, which allow a compact and economical arrangemet. According the slew bearing design, they are single or double row ball, single row cross roller, three row roller slewing ring type, which are widely used in construction machinery, marine equipment, engineering machinery, light industrial machinery, metallurgical machinery, medical machinery, industrial machinery and other industries.