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Slewing Ring Bearings
Slewing ring bearings, also known as slewing bearings, are large bearings with a special structure, capable of with standing axial force, radial force and tilting moment at the same time, and are widely used in machinery and equipment requiring low-speed, heavy-duty rotary or oscillating motion. Compared with traditional bearings, slewing bearings have higher load carrying capacity and larger rotary diameter, but the structure is also more complex, suitable for bearing complex working conditions of the equipment.
LNB Bearings offers a full range of high-quality, competitively priced slewing ring bearings and can be able to provide custom options to meet specific customer demands.
Slewing bearings are a special type of large bearings, the structure usually consists of an inner ring, outer ring, rolling elements (balls or rollers), isolation block or cage, and sealing device, some designs also integrated lubrication system and gear ring to achieve direct transmission. The core function of the slewing bearing is to achieve high-efficiency power transmission and accurate positioning between two relative rotary parts, both load bearing and rotary dual characteristics, which can be in low speed, heavy load, or complex working conditions to maintain reliable operation.
Gearless slewing bearings do not have an integrated gear structure, and their rotary motion has to be realised by means of an external transmission (e.g. motor, hydraulic system). Gearless slewing bearing has the characteristics of simple and compact structure, easy installation, strong bearing capacity, light weight, etc. It is usually used in the occasions with high requirements on space requirements and rotary accuracy.
The external gear slewing bearing's gear structures are located on the outside of the outer ring and directly mesh with the driving pinion (gear motor or reducer) to achieve rotary motion. The design of the external gear slewing bearing makes the gear easy to maintain and lubricate, and the transmission torque is large, and suitable for heavy load conditions. External gear structure can also spread the load, and improve the stability of the bearing, but its external protruding gear may increase the overall size of the equipment, and the installation accuracy and gear protection requirements are high, needs to avoid the intrusion of foreign objects.
(3)Internal Gear Slewing Ring Bearings The internal gear slewing bearings' gear structure is on the inner side of the inner ring and is engaged by built-in drive gears. Through this structure, the internal gear slewing bearings become more compact and space-efficient. At the same time, this design also protects the gear transmission part from the outside contamination and damage during the working process, making it stronger in terms of contamination and corrosion resistance. However, its internal gear processing, upkeep, and lubricant are relatively more complicated, the cost is slightly greater than that of the external gear bearing.
3. Slewing Ring Bearings Characteristics
(1)Structural integration design: Slewing bearing adopts a highly integrated structure of inner and outer rings, rolling bodies (ball or roller), cages and sealing devices, and some models have integrated gears (internal, external or toothless), forming a compact rotary bearing unit.
(2)High load carrying capacity: Slewing bearing bearings can withstand axial load, radial load, and tilting moment at the same time, especially good at low speed, heavy load or complex working conditions to maintain reliable operation.
(3)High precision and high rigidity: Through precision machining and heat treatment process (such as surface quenching, carburising treatment), the raceways and gears of the slewing bearings have high hardness, high wear resistance and dimensional stability, which can meet the stringent requirements of precision equipment for rotary positioning accuracy and dynamic rigidity.
(4)Compact structure, easy to install: Compared with traditional bearings, slewing bearing bearings can simplify the design of equipment and reduce the installation space while providing high bearing capacity, and can be directly connected to the equipment through the flange, reducing the difficulty of assembly.
4. Slewing Ring Bearings Application
Slewing bearings play a key role in all kinds of mechanical equipment, according to the different gear structures, their application scope also varies. The following are the main application scenarios:
(1)Gearless slewing ring bearings: They are mostly used in compact spaces, light loads and scenarios where no additional gearing is required. For example, the rotary scanning frame of medical CT machine, automation equipment, small solar energy tracking bracket, light industrial rotary table, wind power generation and so on.
(2)External gear slewing ring bearings: They rely on the high torque transmission capacity of the outer ring gear, widely adapted to the field of heavy machinery. Such as excavators, tower cranes, truss cranes, marine equipment, radar antenna support and so on.
(3)Internal gear slewing ring bearings: They are commonly used in environments where the internal space of the equipment is limited or where the gears need to be avoided to be exposed due to the fact that the gears are embedded in the inner ring of the bearings, which saves the external space and provides better protection. Such as wind turbine pitch system, radar antenna base, robot joints, automated production lines, metallurgical equipment, optical telescopes and so on
