Air bearing
An air bearing (also known as an aerostatic bearing or a pneumatic bearing) is a bearing in which a forces between two surfaces are supported by air pressure. In other words, it is a surface effect bearing. The air bearing provides a smooth, low friction and consistent movement on the shaft by allowing the minimum amount of lubrication between the shaft and bearing surfaces. This type of bearing is usually used in high speed and high precision applications such as medical equipment, precision machining and optical instruments.
The operation of the air bearing is based on the principle of Bernoulli’s theorem, which states that the pressure of a moving fluid decreases where the speed of the fluid increases. This pressure differential is used to support the load or move a part or shaft. The air bearing basically works by introducing a cushion of air between the bearing surfaces. As the air bearing moves relative to the surfaces, it creates a small pocket of air between them. This pocket of air creates a low pressure zone, the relative pressure between the two surfaces is lower than atmospheric pressure which makes the two surfaces more stable.
The advantage of using an air bearing is that it provides frictionless movement of a part or shaft. This makes it ideal for high precision applications. It also requires minimal lubrication, making it suitable for many applications in medical, semiconductor, and electronics industries. Additionally, this bearing is highly reliable, repeatable and durable.
Air bearings usually require very low pressure to support its load and movement, with pressures as low as 0.1 psi (6 Torr). The typical operating pressure is 0.02 - 0.15 psi (1.3 - 11 Torr). The air supply can be any type of compressed air source, from an air compressor to a pressurized tank. The air pressure should be carefully regulated to lend stability to the air bearing.
In order to ensure the performance of an air bearing, it is important to ensure that it is properly maintained. The proper maintenance includes frequent cleaning, the re-lubrication of the parts and the monitoring of the air pressure. It is also important to ensure that the air bearing is free of any contaminants.
Air bearings have numerous applications, including high speed motors, magnetic levitation systems, positioners, vibration isolation and ultra-precision stages. They can also be used in medical diagnostics, analytical instruments and other high precision systems. With the increasing demand for precision, the use of air bearings is becoming more popular and is expected to continue to grow in the future.
