Bucket wheel excavators typically employ three-row roller slewing bearings, where the three rows of rollers respectively address axial, radial, and overturning moment load requirements. This design disperses loads through line contact between rollers and raceways, achieving 3-5 times higher load capacity compared to ball-type bearings. For instance, a certain excavator model features a 2.5-meter-diameter slewing bearing made of carburized steel with a geared ring, enabling stepless speed regulation via hydraulic motors to accommodate mining needs for minerals of varying hardness. Additionally, the sealing structure adopts a dual rubber ring + labyrinth design, effectively preventing dust ingress and extending lubrication intervals to 500 hours under harsh conditions.

Technical Challenges and Maintenance Key Points?

Dynamic Load Management?: Impact loads generated when the bucket wheel cuts into coal seams can cause raceway fatigue, requiring preload adjustment to ensure even roller force distribution.

Lubrication Optimization?: High-viscosity extreme-pressure lithium-based grease is used, with a centralized lubrication system for timed and quantitative injection to avoid dry friction.

Condition Monitoring?: Vibration sensors monitor bearing operation in real-time to detect early-stage defects such as raceway spalling.