The document discusses lubrication and its types. It defines lubrication as reducing friction between surfaces in contact by interposing a lubricant. There are several types of lubrication depending on the motion between surfaces, including hydrodynamic lubrication which uses fluid pressure to separate surfaces, boundary lubrication where the film is too thin to separate surfaces, and mixed lubrication which is a transition between the two. Extreme pressure lubrication uses additives that react when heated to form protective surface films. Proper lubrication reduces wear, heat, energy consumption, and increases machinery life.

1. Lubricationanditstypes

2. Lubricationanditstypes
Topics ..…
• Fricton
• Lubrication
• Whylubricationisneeded
• Classificationoflubricants
• Typesoflubrication(indetails)

3. Lubricationanditstypes
• Fricton
Is the force resisting the relative motion of solid surfaces ,fluid
layers and material elements sliding against each other .

4. Lubricationanditstypes
• Lubrication
Lubrication is the process or technique employed to reduce wear of one
or both surfaces in close proximity, and moving relative to each other, by
interposing a substance called lubricant between the surfaces to help
carry the load between them .

5. Lubricationanditstypes
• Whylubricationisneeded???
• Friction / Wear
• Heat generation
• Increases life of machinery
• Reduces energy consumption
• Material protection
• Sealing

6. Lubricationanditstypes
• Classificationoflubricants
On the basis of its physical state, we can classify the lubricants
as follows :-

7. Lubricationanditstypes
Typesoflubrication
Considering the nature of motion between moving or sliding surfaces,
there are different types or mechanisms by which the lubrication is
done , They are:
1. Hydrodynamic orThick Film Lubrication
2. Hydrostatic lubrication
3. Elastohydrodynamic lubrication
4. Boundary or thin film lubrication
5. Mixed lubrication
6. Extreme pressure lubrication

8. Lubricationanditstypes
1. Hydrodynamic or (Thick Film Lubrication)
• is exist when the moving surfaces are separated by the pressure of a continuous
unbroken film or layer of lubrication.
• In this type , the load is taken completely by the oil film.
• It depends on the relative speed between the surfaces, oil viscosity, load, and
clearance between the moving or sliding surfaces.

11. Lubricationanditstypes
Application of hydrodynamic lubrication :
Delicate instruments.
Light machines like watches, clocks, guns, sewing machines.
Scientific instruments .
Large plain bearings like pedestal bearings, main bearing of diesel
engine .

12. Lubricationanditstypes
2 . Hydrostatic lubrication
• It is essentially a form of hydrodynamic lubrication .
• But the film instead of being self-generated, the separating
pressure is supplied by an external oil pump .
• Hydrostatic lubrication depends on the inlet pressure of oil and
clearance between the surfaces .

13. Lubricationanditstypes

15. Lubricationanditstypes
Application of hydrostatic lubrication :
This type of lubrication is mainly used in the following areas :
• Two stroke engines .
• Bigger machines .

16. Lubricationanditstypes
3. Elastohydrodynamic lubrication
• Is developed in heavily loaded rolling contacts .
• The contacting surface is elastically deformed,distributing the load
over a greater area .
• High pressure results in increasing viscosity of lubricant , which
improves load capacity .

18. Examples of machinery applications that operate under EHL are:
• rolling element bearings, gear teeth and cam contacts (rolling)
where high rolling contact loads occur.
Lubricationanditstypes

19. Lubricationanditstypes
4. Boundary or thin film lubrication
• Lubrication film is insufficient to separate the contacting surfaces.
• the oil film thickness is so small .
• metal to metal contact occurs between the moving surfaces .

20. Lubricationanditstypes
• Unlubricated vs boundary lub vs hydrodynamic lub

21. Lubricationanditstypes
This type of lubrication is used in the following areas :
1. A shaft starts moving from rest.
2. The speed is very low.
3. The load is very high.
4. Viscosity of the lubricant is too low.

22. Lubricationanditstypes
5. Mixed lubrication
. is the transition betweenHydrodynamic and Boundary lubrication.
. Two surfaces are partly separated, partly in contact .

23. Lubricationanditstypes

24. Lubricationanditstypes
6. Extreme pressure lubrication
. This lubrication is for very high press ,temperature, speed sliding
surfaces .
. Extreme pressure additives are used along with the lubricants .
. They are activated by reacting with the metal surface when the
temperatures are elevated due to the extreme pressure and friction .
. Then form solid surface films of (S,CL and P) , acts as a barrier to
reduce friction, wear, eliminate the possibility of welding .

26. Lubricationanditstypes

27. Lubricationanditstypes
Summary : Stribeck curve

28. Lubricationanditstypes

29. Lubricationanditstypes
Lubrication importance and its cost ….

30. any questions …