A graph with the coefficient of friction on the vertical axis and a duty parameter, viscosity multiplied by speed and divided by load, on the horizontal. Reading left to right, friction is high and flat in boundary lubrication, falls steeply through mixed lubrication to a minimum, then climbs slowly as a full fluid film adds viscous drag. Engineers use it to explain why slow, heavily loaded, thin-oil contacts wear and why going too thick only wastes energy.
Low speed, shock load and a thin oil puts that kiln trunnion way over on the left side of the Stribeck curve.
Sketch it on a whiteboard when an operator wants a thinner oil to cut energy: the curve shows exactly where the savings stop and the wear starts.
Also heard as
- Stribeck diagram
Related terms
Boundary lubrication
Regime where surfaces touch through the oil and protection comes from chemical surface films, not fluid pressure.
Mixed lubrication
Transitional regime where the load is shared between a partial fluid film and asperity contact.
Hydrodynamic lubrication
Full-film lubrication in which motion drags oil into a narrowing gap and builds enough pressure to float the load.
Coefficient of friction
Ratio of the force resisting sliding to the normal load pressing two surfaces together.