Causes of Heating during the Use of Slewing Bearing

1. Analysis on the causes of heating of slewing bearings:

Possible reason 1:

The shaft size of the slewing bearing is too large that the bearings will be tight.

Solution:

Provide an appropriate tolerance for the shaft and strictly prohibit excessive tightening.

Possible reason 2:

Aluminum three-layer ring seal friction will generate heat

Solution:

Grease should be applied to reduce frictional resistance when installing seal holes and rings.

Possible reason 3:

The slewing bearing seat is coated with too much grease or the oil level is too high.

Solution:

The slewing bearing removes excess grease through the sealing hole and the oil lubrication lowers the oil level just below the bearing box.

Possible reason 4:

Improper grease or lubricant type causes lubricant failure.

Solution:

Re-select the appropriate lubricant type.

Possible reason 5:

Low oil level and  insufficient grease.

Solution:

The oil level on the outside of the shaft diameter should be exactly lower than the holder and fill with suitable grease.

Possible reason 6:

The inner ring and the seal ring have frictions.

Solution:

Stop and check the clamping ring screws to ensure that the inner ring is securely attached to the shaft, that the free end bearings are installed correctly, and that the rollers are aligned with the outer ring centerline.

2.  Lubrication and maintenance methods of slewing bearing:

(1) The slewing bearing is coated with a small amount of No. 2 extreme pressure lithium grease (GB/T7324-1994) when the slewing bearing is delivered from slewing bearing manufacturers, and it should be filled with new grease according to different working conditions when it is used.

(2) Slewing bearing rollers should be regularly filled with grease. Generally ball bearings are refueled every 100 hours of operation, and roller bearings are refueled every 50 hours. In special working environments, such as tropical, high humidity, dusty, large temperature differences, and continuous operation, the lubrication cycle should be shortened. The machine must be filled with new grease before and after a long-term shutdown. For each lubrication, the raceway must be filled with grease until it leaks from the sealing belt. When grease is injected, the slewing bearing must be slowly rotated to make the grease filled evenly.

(3) The tooth surface should often remove debris, and apply the corresponding grease.

(4) The pre-tightening force of the bolts should be checked after the first 100 hours of operation of the slewing ring turntable, and every 500 hours of operation thereafter, and sufficient pre-tightening force must be maintained.

(5) Pay attention to the operation of the slewing bearing during use. If noise, impact, or sudden increase in power is found, the machine should be shut down immediately for inspection, troubleshooting, and disassembly and inspection if necessary.

(6) It is forbidden to directly flush the slewing bearing with water during use, so as to prevent water from entering the raceway, and prevent hard foreign objects from approaching or entering the tooth meshing area.

(7) Check the integrity of the seal frequently. If the sealed bag is found to be damaged, it should be replaced in time, and if it is found to be off, it should be reset in time.