①Because the viscosity of gas is much lower than that of liquid, the viscosity of air at room temperature is only 1/5000 of 10 mechanical oil, and the friction of bearings is proportional to the viscosity, so the friction of gas bearings is lower than that of liquid lubricated bearings.

 

 

 

② The applicable speed range of gas bearings is large, the friction resistance is low, the temperature rise is low, in the speed up to 50,000 RPM, the temperature rise is not more than 20 ~ 30℃, the speed is even up to 1.3 million RPM. Aerostatic bearings can also be used at very low speeds or even zero speeds.

 

 

 

③ Wide temperature range of gas can be maintained in a large temperature range, its viscosity is very little affected by temperature (when the temperature rises, the viscosity also slightly increased, such as the temperature from 20℃ to 100℃, air viscosity increases 23%), therefore, the temperature range of gas bearings can be up to -265℃ to 1650℃.

 

 

 

(4) Bearing capacity The bearing capacity of low dynamic pressure bearings is proportional to viscosity, and the bearing capacity of gas dynamic pressure bearings is only a few thousandths of that of liquid dynamic pressure bearings of the same size. Due to the compressibility of gas, the bearing capacity of gas dynamic pressure bearings is limited. Generally, the load per unit projected area can only be added to 0.36 mpa.

 

 

 

(5) High processing accuracy requirements

 

 

 

In order to improve the bearing capacity and film stiffness of gas bearings, smaller bearing clearances (less than 0.015 mm) than liquid lubricated bearings are usually used, and the accuracy of parts needs to be improved accordingly.