What is an Air Bearing?



What is an Air Bearing?


An air bearing is a non-contacting system where a gas film (typically air)
acts as the lubricant that separates the two surfaces in relative motion.

The Basic Principles of an Air Bearing Spindle

spindle

Types of Air Bearing

There are two main kinds of air bearing:

  1. Aerostatic:

    • Externally pressurised: A separate external supply of air is fed under
      pressure between the two surfaces being kept apart.

    • It is a continuous flow system where pressurised gas from the source
      flows through restrictors into the clearance between the bearing surfaces escaping to the atmosphere at the outside edges of the bearing.

    • Types: Simple orifice fed, Pocketed orifice, Slot fed and Porous.

    aerostatic bearing


  2. Aerodynamic:

    • Self generating: The supporting film is generated by the relative motion
      of the two surfaces being kept apart.

    • An aerodynamic bearing can be of several types. The design characteristics
      differ greatly between journal and axial bearings and they can suffer
      problems of instability.

    • Types: Simple cylinders, Tri-lobe, Grooved (axial / herringbone / spiral)
      and Stepped.

aerodynamic bearing