What are the differences between a sealed ball bearing, an open bearing and an oil lubricated bearing?

1. Sealed Ball Bearings
Structure: Sealed ball bearings feature integrated shields (e.g., metal 2Z shields) or contact seals (e.g., rubber 2RS seals) that enclose the rolling elements, preventing contamination ingress and lubricant leakage . They are pre-lubricated with high-performance grease (e.g., lithium soap-based) during manufacturing, ensuring maintenance-free operation .

Advantages:
Contamination Resistance: Ideal for dusty, humid, or corrosive environments (e.g., agricultural machinery, conveyors) .
Reduced Maintenance: No relubrication required, minimizing downtime .
Corrosion Protection: Seals block moisture, extending service life in harsh conditions .

Limitations:
Speed Restrictions: Friction from contact seals can limit rotational speeds .
Lubricant Degradation: Pre-filled grease may degrade over time, limiting longevity in high-temperature applications .

2. Open Bearings
Structure: Open bearings lack seals or shields, exposing the rolling elements to the environment. They rely on external lubrication systems (grease or oil) and adjacent machine components for contamination control .

Advantages:
High-Speed Compatibility: No seal friction allows performance in precision machinery (e.g., spindles, electric motors) .
Customizable Lubrication: Supports periodic relubrication with grease or oil, enabling tailored maintenance for extended lifespan .
Cost-Effectiveness: Lower initial cost compared to sealed variants .

Limitations:
Vulnerability to Contaminants: Requires clean operating environments or supplementary sealing solutions .
Maintenance Dependency: Regular lubrication and inspection are mandatory to prevent premature failure .

3. Oil-Lubricated Bearings
Structure: Oil-lubricated bearings utilize oil as the primary lubricant and may adopt open or semi-sealed designs (e.g., shielded 2Z bearings). Oil is supplied via circulating systems, oil baths, or drip feeders .

Advantages:
High-Temperature and High-Speed Performance: Superior heat dissipation supports conditions (e.g., turbines, compressors) .
Enhanced Lubrication Control: Continuous oil flow flushes out wear particles, maintaining cleanliness .

Limitations:
System Complexity: Requires auxiliary components (pumps, filters, reservoirs), increasing installation costs .
Leakage Risks: Open designs demand precise sealing integration to avoid oil loss .

At FTM bearing, we engineer precision into every bearing. For applications demanding peak performance, our open bearings feature ultra-smooth raceways and hybrid ceramic balls.
Partner with us to elevate your machinery’s efficiency and longevity. Contact our technical team today for a customized bearing solution that powers your success.