25 December 2016

Types of Bearing

Bearing is a mechanical element that permits relative motion between two parts, such as the shaft and the housing, with minimum friction. 
The function of the bearing are the following :
  • The bearing ensures free rotation of the shaft or axle with minimum friction.
  • The bearing supports the shaft or axle and holds it in the correct position.
  • The bearing takes up the forces that act on the shaft or the axle and transmit them to the flame.
Bearing are classified in different ways :

Depending upon the direction of the force that acts on them :
  1. Radial bearing
  2. Thrust bearing
Radial bearing supports the load, which is perpendicular to the axis of the shaft.

Radial bearing

Thrust bearing supports the load, which acts along the axis of the shaft.

Thrust bearing

Depending upon the types of friction :

  • Sliding contact bearing
Types of sliding contact bearing :
  • Hydrodynamic bearing 
  • Hydrostatic bearing 
  • Rolling contact bearing 
Types of rolling contact bearing :

  • Deep groove ball bearing
  • Cylindrical roller bearing
  • Angular contact bearing
  • Self-aligning bearing
  • Taper roller bearing
  • Thrust ball bearing
Sliding contact bearing is any bearing that works by sliding action, with or without lubricant. This group encompasses essentially all types other than rolling-element bearings.
Sliding contact bearing is also called plain bearing, journal bearing or sleeve bearing.
Lubrication is critical to the operation of plain bearings, so their application and function are also often referred to according to the type of lubrication prin­ciple used. Thus, terms such as hydro­dynamic, fluid-film, hydrostatic, boundary-lubricated, and self-lubricated are designa­tions for particular types of plain bearings.

Application of Sliding Contact Bearing :

  • Crankshaft bearing in petrol and diesel engine
  • Centrifugal pumps
  • Large size electric motor
  • Steam and gas turbine
  • Rope conveyors
Rolling contact bearing is a bearing which carries a load by placing rolling elements (such as balls or rollers) between two bearing rings called races. The relative motion of the races causes the rolling elements to roll with very little rolling resistance and with little sliding.  
The principal types of roller bearings are cylindrical, needle, tapered, and spherical. In general, they have higher load capacities than ball bearings of the same size and are widely used in heavy-duty, moder­ate-speed applications. However, except for cylindrical bearings, they have lower speed capabilities than ball bearings. See the following figure for roller bearings. 
Rolling contact bearing
Application of Rolling contact bearing :
  • Machine tool spindles
  • Automobile front and real axles
  • Gear boxes
  • Small size electric motors
  • Rope sheaves
  • Crane hooks
  • Hoisting drums