A bearing is a machine part that allows relative motion between two surfaces with minimal friction.
In a rolling element bearing, the primary motion is a rolling motion using a ball or roller. There is direct contact between the ball/roller and the inner and outer surfaces (races).
In a fluid film bearing, the relative motion between the two surfaces is a sliding motion on a shear of film (the lubricant). There is no contact of the surfaces except during start-up or shutdown.
A key difference between rolling element and fluid film bearings is the expected life of the bearings. Rolling element bearings typically have a predictable life based on the operating conditions; fluid film bearings, when properly designed and maintained, can operate for decades.
Waukesha Bearings specializes in the engineering, design and manufacture of hydrodynamic fluid film bearings.
|Hydrodynamic Fluid Film Bearings||Rolling Element Bearings|
|Life Expectancy||Indefinite||Limited Life (L10)|
|Speed Limitations||Approaches Burst Limit||Limited to DN|
|Noise||Quiet||Can Be Noisy|
|Cost||Low to High||Low to Moderate|
|Assembly/Repair||Easy to Difficult||Easy|
|Tolerance for Misalignment||Tolerant||Intolerant|
|Operating Temperature||Cryogenic to High||Cryogenic to Extreme|
|Power Loss||Moderate to High||Low to Moderate|
|Lubricant Requirements||Minimal to High||None to Low|
|Oil Pressure||Low to High||None to High|
|Natural Frequency Control||Good||Poor|