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Which bearing offers lowest friction

Which bearing offers lowest friction Correct Answer Aero-static bearing

Concept:

A bearing is a machine component that supports another machine element. It permits relative motion between the contacting surfaces while carrying the load.

Classification of Bearings:

  1. Based on the direction of the load
    • Radial bearing
    • Thrust bearing
  2. Based on the nature of the contact
    • Sliding contact bearing
    • Rolling contact bearing

The rolling contact bearing can be further classified into:

  1. Ball bearings
  2. Roller bearings

Types of journal bearing are:

a) Aero-static bearing: In this bearing, pressurized gas (generally air) acts as the lubricant in the system which separates the two surfaces in relative motion. The two surfaces do not touch, thus no problem of friction, wear, etc. A diagram of the air bearing is shown below:

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b) Hydrodynamic bearing: In this, the shaft and the journal are in contact at stationary conditions. As the shaft rotates, it pressurizes the fluid and due to wedging action, a gap is created between the two surfaces.

c) Hydrostatic bearing: In these bearings, fluid is supplied using an external device (pump). The fluid is usually oil, water, etc. They provide lubrication even at stationary conditions.

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