Journal Bearing - Minimum Film Thickness
Minimum oil-film thickness in a journal bearing - Sommerfeld-based approximation for safe operation.
Min film thickness
45.0µm
Status
Safe full-film
Formula, assumptions, and limits
$$h_{min} = c (1 - \varepsilon)$$
c = radial clearance, ε = eccentricity ratio (0 centred, 1 metal-to-metal). 20 µm typical minimum. Ship shaft bearings c = 0.1-0.2 mm. ε increases with load, decreases with speed.
Symbol legend
| Symbol | Meaning | Unit | Source |
|---|---|---|---|
| $c$ | Radial clearance | mm | maker data |
| $ε$ | Eccentricity ratio | - | bearing operating |
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