What is usually the cause for failed bearings?
Lubrication problems and contamination are usually the leading causes of bearing failures, often worsened by misalignment or overload. Understanding these drivers helps maintenance teams extend life and reduce downtime.
The leading culprits behind bearing failure
Below is a concise overview of the main categories that drive most bearing failures in industrial settings. The list captures the practical factors maintenance teams encounter across sectors, from manufacturing floors to energy plants.
- Lubrication problems (insufficient lubrication, degraded lubricant, incorrect viscosity, or poor distribution to the raceways)
- Contamination (dust, dirt, water ingress, coolant or metal particles entering the bearing)
- Misalignment and improper mounting (shaft runout, housing misfits, improper seating or tightening, and poor fit tolerances)
- Overload and excessive loads or speeds (shock loads, heavy moment loads, high RPMs, or operating conditions beyond design)
- Wear and fatigue (surface fatigue from repeated stress cycles leading to spalling or pitting)
- Corrosion and chemical attack (moisture, aggressive environments, or incompatible lubricants reacting with bearing materials)
- Electrical damage (bearing currents causing pitting and micro-arcing, especially in motor-driven equipment)
- Thermal issues (overheating due to friction, poor cooling, or sealing failures that trap heat)
In practice, prevention centers on controlling lubrication quality and cleanliness, ensuring correct installation, and avoiding overload. Regular monitoring and timely intervention are essential to stave off the most common failure modes.
Lubrication and contamination: the two biggest failure drivers
Lubrication challenges
Choosing the right lubricant, applying it correctly, and maintaining its condition are critical. Issues include insufficient grease or oil film, incorrect viscosity for the operating temperature, and lubricant breakdown that leads to varnish, oxidation, or additives losing effectiveness. Inadequate lubrication often causes metal-to-metal contact, accelerated wear, and heat buildup.
Contamination pathways
Seals and housing design help keep dust, water, and process fluids out, but breaches happen. Contaminants can abrade raceways, clog lubrication paths, and accelerate corrosion. Cleanliness during assembly, proper seal selection, and effective filtration are essential to minimize ingress and prolong bearing life.
Mechanical and operational factors that compound risk
Alignment and mounting errors
Even small misalignments or improper mounting can misload the bearing raceways, increasing friction and heat. Over time, this accelerates wear and can trigger early failure. Regular alignment checks and correct tightening procedures are standard preventive steps.
Overload and speed conditions
Bearings are designed for specific load and speed ranges. Exceeding these limits, experiencing frequent shock loads, or subjecting components to high moment loads can push bearings into premature wear modes and fatigue failure, especially when lubrication is compromised.
Material wear and corrosion
Material defects, surface fatigue, or corrosive environments can initiate micro-cracks and spalls. Selecting appropriate bearing materials for the operating environment and applying protective coatings or seals helps mitigate these risks.
Diagnostics and prevention: turning data into longer bearing life
Maintenance teams increasingly rely on condition monitoring to catch failures early. Techniques include vibration analysis, thermography, oil or grease analysis, and seal integrity checks. A reliability-centered maintenance approach—combining proper lubrication management, contamination control, accurate mounting, and reliable seals—significantly reduces downtime and extends bearing life.
Summary
Across industries, the most common root causes of bearing failures are lubrication problems and contamination, with misalignment, improper mounting, and overload acting as frequent amplifiers. Preventive strategies focus on reliable lubrication practices, rigorous cleanliness, accurate installation, and proactive condition monitoring. By prioritizing these areas, plants can reduce unplanned outages and improve overall equipment reliability.
