Rotary bearing is a kind of large bearing which can bear comprehensive load, and can bear large axial, radial load and overturning moment at the same time. Slewing bearing is also called rotary bearing. Some people also call it rotary bearing and rotary bearing. Rotary disk bearings are widely used in the real industry. They are called "the joints of machines". They are the important transmission parts of machinery that need to rotate relative motion between two objects and bear axial force, radial force and overturning moment at the same time. With the rapid development of machinery industry, slewing support has been widely used in marine equipment, construction machinery, light industrial machinery, metallurgical machinery, medical machinery, industrial machinery and other industries. Next we will briefly introduce the light type slewing bearing and single row ball slewing bearing.