Plain Bearing Calculator
Calculate power loss, oil wedge thickness, and minimum oil consumption for plain (journal) bearings with circulating lubrication. Based on validated methodology for marine plain bearings.
Plain Bearing Calculator
About This Calculator
This analysis considers plain (journal) support bearing utilizing circulating lubrication with a steel-babbitt friction pair. The calculations are based on a methodology for marine plain bearings, which has been validated through practical applications.
To perform these calculations, the following input parameters must be defined: the shaft diameter (D), bearing length (L), radial load (F), rotational speed (n), and the diametral clearance (Δ) between the shaft and bearing. Since the heat balance calculations are beyond the scope of this study, the oil's dynamic viscosity (μ) is set at the operating temperature.
The results of the calculations provide the bearing's power loss (P), the thickness of the oil wedge (y), and the minimum required oil flow rate (Q) to ensure proper bearing operation.
Initial Data
- F: Radial load
- n: Shaft speed
- D: Shaft diameter
- L: Bearing length
- Δ: Diametral clearance between the shaft and the inner diameter of the bearing
- μ: Dynamic oil viscosity at service temperature
Results Data
- P: Power dissipated during bearing operation
- y: Oil wedge thickness (minimum film thickness)
- Q: Minimum oil consumption required for proper bearing function
Key Formulas
Bearing Pressure
Surface Velocity
Sommerfeld Number
Power Loss
Oil Wedge Thickness
Oil Flow Rate
Common Oil Viscosity Values
Reference values for dynamic viscosity at operating temperature (40°C)
| Oil Grade | Viscosity (Pa·s) | Typical Applications |
|---|---|---|
| ISO VG 32 | 0.029 - 0.035 | High-speed spindles, light machinery |
| ISO VG 46 | 0.041 - 0.051 | Hydraulic systems, general machinery |
| ISO VG 68 | 0.061 - 0.075 | Industrial gearboxes, medium loads |
| ISO VG 100 | 0.090 - 0.110 | Heavy machinery, marine applications |
| ISO VG 150 | 0.135 - 0.165 | Slow-speed, high-load bearings |
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