KEVOS® MAKEOS · Engineering
Thrust Pad Bearing Check (Unit Load, PV, Friction Loss, Oil Flow)
Is this thrust bearing’s unit load and PV within limits, how much power does friction waste, and how much oil must flow through it to carry the heat away?
Check of a flat or tilting-pad thrust bearing: pad area from the ring and pad coverage, unit load, mean sliding velocity and PV (as the thrust bearing pad tool) against your allowable values, friction power loss from the friction coefficient, and the oil flow needed to remove that heat for the allowed oil temperature rise (as the coolant flow for a heat load tool) against the oil supply.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Outside diameter | mm | Outside diameter of the thrust ring. |
| Inside diameter | mm | Inside diameter of the thrust ring. |
| Pad coverage of the ring | % | Share of the ring covered by pads (the rest is oil grooves). |
| Thrust load | N | Axial load on the bearing. |
| Speed | rpm | Shaft speed. |
| Friction coefficient | Friction coefficient of the running bearing (from its type and lubrication). | |
| Oil | ||
| Allowed oil temperature rise | K | Rise in oil temperature you accept through the bearing. |
| Oil specific heat | kJ/(kg·K) | Specific heat of the oil. |
| Oil density | kg/m³ | Density of the oil. |
| Limits | ||
| Allowable unit load | MPa | Allowable unit load for the bearing material and type. |
| Allowable PV | MPa·m/s | Allowable PV for the bearing material and type. |
| Oil supply available | L/min | Oil flow available to the bearing. |
Method and formulas
- Area = π (D_o² − D_i²) ÷ 4 × coverage; P = W ÷ area; V = π (D_o + D_i) ÷ 2 × n; PV (as the thrust bearing pad tool).
- Friction loss = μ W V.
- Oil flow = loss ÷ (ρ c_p ΔT) (as the coolant flow for a heat load tool).
- Example: 1.9771 MPa, PV 17.857; friction wastes 903.21 W, needing 2.2089 L/min of oil.
Limitations
- Uniform load over the pads; misalignment concentrates load on some pads.
- The friction coefficient must suit the regime (boundary, mixed or full film).
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Check a thrust collar or pad bearing
- Size the oil supply for a thrust bearing
- Compare pad areas for a new load
Who it is for
- Design engineers
- Maintenance engineers
- Lubrication engineers
What you get
- Pad area, unit load, velocity and PV
- Friction power loss
- Oil flow needed
Interpreting the result
- If PV is too high, more pad area or a lower speed helps; if the oil flow is short, raise the allowed rise only within the oil’s limits.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 2338–2356, 371–374. Topic reference; no source tables or recommended settings are reproduced.
WORKOS tools are screening and decision-support utilities. Verify important financial, engineering, safety, legal or operational decisions using appropriate professional standards and your organisation’s approved data.
Open the Thrust Pad Bearing Check (Unit Load, PV, Friction Loss, Oil Flow) calculator
