Rotary bearings are a special type of large-scale bearing that can simultaneously withstand large axial loads, radial loads, overturning moments, and other comprehensive loads. In general, turntable bearings are equipped with installation holes, lubricating oil holes, and sealing devices, which can meet the different needs of various types of main engines working under different working conditions. On the other hand, turntable bearings themselves have the characteristics of compact structure, easy rotation guidance, easy installation, and easy maintenance, and are widely used in large rotating devices such as lifting and transportation machinery, mining machinery, construction machinery, port machinery, and missile launchers.