Maintenance of Crane Slewing Bearings: A Practical Four-Step Guide
Published on:
2026-04-10 15:34
The slewing bearing of a crane is a critical “joint” component, and its maintenance is essential for safe and reliable operation. This article introduces a four-step method to properly maintain slewing bearings.
1. Inspection of Slewing Bearing Bolts
Before each operation—or at least once a week—the bolts on the slewing bearing must be inspected.
- After the first 100 operating hours, check whether the bolts are loose.
- Perform another inspection at 300 operating hours.
- Thereafter, inspect every 500 operating hours.
- Under severe working conditions, the inspection interval should be shortened accordingly.
When replacing bolts:
- Clean the bolts thoroughly.
- Apply thread-locking adhesive before tightening.
Regular inspection and tightening can effectively prevent fatigue failure of the bolts.
If any looseness is detected during inspection:
- Stop operation immediately.
- Contact after-sales service engineers.
- Professional personnel should determine whether disassembly and further inspection are required.
2. Routine Inspection of the Slewing Bearing
Regular inspection ensures proper functionality and early detection of potential issues.
- Check the flexibility of rotation periodically. If abnormal noise or impact is detected, stop the machine immediately for inspection and troubleshooting. If necessary, contact a service engineer for further examination.
- Inspect the gear ring regularly for cracks or damage. Examine the meshing tooth surfaces for signs of:
- Seizure
- Scuffing
- Tooth surface spalling
- Seizure
- Check the sealing condition regularly.
- Replace damaged seals promptly.
- Reinstall any detached seals immediately.
- Replace damaged seals promptly.
3. Lubrication of Gear Teeth
Apply anti-rust oil to the gear ring of the slewing bearing in a timely manner.
During operation:
- Prevent hard foreign objects from approaching or entering the gear meshing area, as they may cause damage to the teeth.
4. Lubrication of the Raceway
The raceway must be lubricated with grease regularly, depending on the working environment.
- Before and after long periods of inactivity, the slewing bearing must be fully filled with grease.
- When cleaning the crane using a steam jet cleaner or fixed water spray system:
- Ensure that water does not penetrate into the slewing bearing connection.
- Re-lubricate the bearing immediately after cleaning.
- Ensure that water does not penetrate into the slewing bearing connection.
- In special working environments—such as tropical climates, high humidity, dusty conditions, large temperature variations, or continuous operation—the lubrication interval should be shortened.
- Grease should be applied while the slewing bearing rotates slowly.
- When grease begins to overflow from the seals, the filling process is complete.
- The excess grease forms a thin film that also serves a sealing function.
- When grease begins to overflow from the seals, the filling process is complete.
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