What components does a slewing bearing consist of?

slewing-bearing-compositionWhat components does the slewing bearing consist of: The slewing bearing consists of inner ring, outer ring, rolling elements, cage, seals, lubricating oil and other components.

1. Inner ring of slewing ring (upper race): it can be toothed or toothless. It is made of precision raceways made of carbon steel and can transmit load and relative motion from two rings. The inner and outer rings are selectively hardened to the required surface and depth to transfer the high stresses exerted during equipment operation.

2. Slewing bearing outer ring (lower seat ring): It can also have teeth or no teeth. Like the inner ring, it is fixed with the rotary sleeve and the shell by high-strength bolts. The rigidity of the outer ring is ensured by the chassis structure that supports it.

3. Slewing ring rolling elements: The rolling elements are the core components of the slewing bearing. They roll between the inner ring and the outer ring to help bear and transmit loads. The rolling elements of the slewing bearing can be balls or rollers. The contact points between rolling elements and raceways have fewer load cycles. During design calculations, the load-carrying capacity is mainly calculated to determine the maximum contact stress at the contact point between the rolling elements and the raceway.

4. Slewing bearing cage: The cage of the slewing bearing is its key component, and it has different structural forms such as integral type, segmented type, isolation block type, etc.

Integral cage and segmented cage: These two types of cages are usually made of 20-gauge steel or ZL102 cast aluminum alloy.

Isolation block cage: This type of cage is usually made of polyamide 1010 resin, ZL102 cast aluminum alloy, etc.

5. Slewing ring seal: The function of the seal is to protect the slewing bearing from external pollutants and prevent the loss of lubricant. The seal of the slewing bearing is an important component, mainly used to prevent the leakage of grease in the raceway and the intrusion of foreign objects such as mud, water, dust, etc. from the external environment into the raceway. It can protect the raceways, rolling elements and isolation bodies to a certain extent, thereby extending the service life of the slewing bearing.

The most commonly used seal for slewing bearings is nitrile rubber seal. If it is at high temperature, fluororubber seal can be used. If it is at low temperature, silicone rubber seal can be used. These seals are usually made of oil-resistant nitrile rubber NBR and are suitable for most use environments. Depending on the operating temperature, you can also choose low-temperature silicone rubber seals that are resistant to low temperatures and fluororubber seals that are resistant to high temperatures.

6. Slewing bearing Isolation Block: Lubricating devices are usually used to supply lubricant to slewing bearings to reduce friction and wear. Mainly used to ensure the normal operation of the slewing bearing.

The inner cavity of the slewing bearing is lubricated by adding grease through the lubricating oil nozzle located on the outer race. The inner ring gear of the slewing bearing and the pinion of the slewing motor are lubricated by pre-added grease. Under normal working conditions (working 8 hours a day), the slewing bearing should be lubricated every 100 hours of operation.

When it comes to the choice of grease, we choose to use grease. Grease is a high-performance grease with protective properties such as super anti-wear, anti-rust and resistance to water washout. This grease offers excellent resistance to rust and corrosion as well as water washout, making it particularly suitable for equipment that is frequently exposed to wet conditions.