What is an air bearing？Is it related to air?

Bearings, I believe everyone is familiar with them. The rolling bearings that we commonly use should be the most familiar. They are important components in contemporary mechanical equipment. 

So what is an air bearing?

In 1854, the French G.A Ian proposed the idea of using gas as a lubricant, and finally in 1896, the first air bearing came out.

Air bearing: A plain bearing that uses gas as a lubricant. The most commonly used gas lubricant is air, but nitrogen, argon, hydrogen, helium or carbon dioxide can also be used as required. In gas compressors, expanders and circulators, the working medium is often used as a lubricant.

Air bearing refers to a bearing that supports the load by means of the pressure air film formed between the sliding surfaces of the bearing, and the sliding surfaces are completely separated by the air film during operation. 

The air bearing belongs to the fluid sliding bearing in the sliding bearing. It is fluid lubricated during operation, and its lubricating medium is air.

According to the formation mechanism of the pressure air film, air bearings are mainly divided into two categories: aerodynamic bearings and aerostatic bearings.

The pressure air film of the aerodynamic bearing is formed by the mutual movement of the sliding pair to bring the air into the area of convergence between the surfaces of the sliding pair. The air film is roughly wedge-shaped, see Image 1. 

Since aerodynamic bearings do not require an external air source, they are also called "self-acting bearings".

The pressure air film of the aerostatic bearing is formed by the introduction of the external compressed air between the sliding surfaces through the restrictor, as shown in Image 2. 

Aerostatic bearings require a clean external air source.