Slewing bearing is a kind of large bearing with special structure, which can bear axial load, radial load, overturning moment and other large comprehensive load at the same time, and integrates various functions such as bearing, rotation, transmission and fixation. Generally speaking, the turntable bearing itself is equipped with mounting holes, lubricating oil and sealing devices, which can meet the different requirements of various hosts working under different working conditions; on the other hand, the turntable bearing itself has compact structure, convenient guiding and rotation, and simple installation, Easy to maintain and so on. It is widely used in lifting and transportation machinery, mining machinery, construction machinery, port machinery, wind power generation, medical equipment, radar, missile launcher and other large rotating equipment.

Generally, mounting holes, internal gears or external gears, lubricating oil holes and sealing devices are provided on the bearings, which can make the design of the host compact, easy to guide, and easy to maintain. There are four series of rotary bearings: toothless, outer and inner four-point contact ball bearings, double row angular contact ball bearings, crossed cylindrical roller bearings, crossed tapered roller bearings, and three-row cylindrical roller composite bearings. Among them, the four-point contact ball bearing has a high static load capacity, the cross cylindrical roller has a high dynamic load capacity, the pre-interference of the cross tapered roller bearing can make the bearing have a higher support stiffness and rotation accuracy. Three rows of cylindrical roller combination bearings due to the increase in carrying capacity, resulting in lower bearing height, various forces borne by different raceways, so in the case of the same force, the bearing diameter can be greatly reduced, so that the host is more compact. It is a slewing bearing with high load capacity.

Slewing bearing is an important part of many mechanical equipment, is a kind of metal products. If not used for a long time, or improper maintenance, it is easy to rust, thereby reducing its performance, or even completely scrapped. Therefore, in daily use, the anti-rust work of the slewing bearing is very necessary. Common anti-rust methods are soaking, brushing and spraying. The special coating can maintain the performance of the bearing. Although the equipment has long durability by spraying special paint or oxidation treatment on the outer surface, the commonly used anti-rust method is chrome plating (TDC) or nickel plating.

Most bearing failures are caused by improper lubrication or impurity contamination. Slewing bearing (slewing bearing) seal on the one hand is to prevent the filling of grease leakage; on the other hand is to prevent the outside of the dust, impurities, moisture intrusion bearing, affect the normal work. Since most of the slewing bearings work under heavy load and low speed, the sealing form of the bearing adopts two structures: rubber sealing ring seal and labyrinth seal. The rubber sealing ring itself has a simple structure. Small footprint, reliable sealing performance, etc. And has been widely used. However, its disadvantage is that the rubber sealing lip is prone to premature aging at high temperatures and loses its sealing performance. Therefore, working under high temperature slewing bearings should adopt labyrinth seal.