Bearings support rotating shafts, reduce friction and carry loads. Because almost every rotating machine depends on them, bearing health is a strong indicator of overall equipment health.
Main Bearing Types
Rolling element bearings use balls or rollers between inner and outer rings. Deep groove ball bearings handle moderate radial and axial loads at high speeds, while cylindrical, spherical and tapered roller bearings carry heavier loads. Plain (journal) bearings rely on a film of lubricant between the shaft and the bearing surface and are used for large, heavy or high-speed machines such as turbines and compressors.
How Bearings Fail
- Contamination: dirt and water cause abrasion and corrosion.
- Poor lubrication: too little, too much or the wrong grease or oil.
- Misalignment and imbalance: create additional loads and heat.
- Improper installation: hammering, wrong fits or incorrect preload.
- Electrical damage: stray currents from drives can erode raceways.
Selection Considerations
Engineers evaluate load magnitude and direction, speed, operating temperature, required life and environmental conditions. Standard life calculations such as L10 provide a statistical estimate, but real-world life depends strongly on cleanliness and lubrication quality.
Best Practices
Store bearings in clean, dry conditions, use induction heaters for mounting when appropriate, and follow the manufacturer’s grease quantities. Monitor vibration and temperature to catch early defects. A small investment in installation quality and condition monitoring usually repays itself many times over.