Basic Lubrication, Tribology

Lubrication is part of tribology. Tribology is the science and technology of the interaction between surfaces moving relative and matters relating to the interaction.

Lubrication on Ball Bearing

Lubrication is the process of inserting a specific ingredient (called a lubricant) between the two surfaces contact each other with the aim of reducing the frictional forces and therefore reduces wear.

In general, the function of lubricants are:

• Reduce friction

• Reduce wear

• Preventing Corrosion

• Maintain temperature

• Preventing Contamination

• Power Transfer
  
  
  

  

  Lubrication Function

Lubricants work on some regimes as follows::

• Hydrodynamic lubrication is a lubrication condition when the shape and relative motion of the moving surfaces results in lubricant layer is thick enough to separate the two surfaces
  
  

  

  Hydrodynamic Lubrication

  
  

• Boundary Lubrication is the lubrication conditions in which the lubricant layer is not able to maintain the full film.
  

  

  Boundary Lubrication

  
  

  
  

  
  

• Elastohydrodynamics lubrication
  
  

  

  Elastohydrodynamics Lubrication

• Mixed lubrication
  
  

  

  Mixed Lubrication

Regime in lubrication can also be explained by the curve Streibeck - Hersey below. Coefficient of friction (Y axis) is affected by the viscosity (Z), Velocity (N), and Load (P). When the load and velocity fixed, then the coefficient of friction will be great if the viscosity is low. similarly if the viscosity is too high, it will increase the keofisien friction caused by friction between the molecules of fluid lubricant itself.

Stribeck - Hersey Curve

Lubrication Transition

Generally there are two types of lubricants, namely: lubricating oils and greases.

Lubricating oils consist of base oil + additive components, while grease consisting of components bese oil + additives + thickener.

Lubricant Formula

BASE OIL 

Base oil is a part or component of the lubricant determines the quality and performance

Beberapa jenis Base oil

API (American Petroleum Institute) classifies base oils into groups where the group I and group II are classified into types of mineral base oil, while Group III and IV are classified into syntethic base oil.

Klasifikasi Base Oil API

Mineral base oil is produced through a process of refining crude oil, whereas oil Syntetic bese. a product made by a chemical reaction with molecular weights lighter to form oil property as planned. Base oil is superior because its compounds are more homogeneous.

Mineral vs Sintetik

Kelebihan dan kekurangan Base oil Sintetik

ADDITIVE

Lubricating oil additives can be defined as compounds that can improve or strengthen the specifications or characteristics of lubricating oil base oil.

Type of additive materials used in lubricants are:

• Dispersant
• Detergent :
• Oxidation inhibitor
• Friction modifier
• EP/antiwear agent
• Emulsifier
• Demulsifier
• Pour point depressant
• Foam inhibitor
• Rust and corrosion inhibitors
• Viscosity modifier

Engine Oil Common Additive

Non Engine Oil Common Additive

In the selection of lubricants, there are two important standards that must be considered, namely: Viscosity and Performance Standards (API, ACEA, OEM standard, dsb)
Basic Lubrication, Tribology

More ebooks :

         Ebook For Engineers

Ebook For Engineers 

More than Thousand Ebook For Engineers 

·         Ebook For Engineers