Introduction

Gas bearings have been used to support rotors in machines since the 1960. They have been designed for several applications, including gyros, supports for magnetic heads in computer hard disc’s, and special machine tools. Gas bearings are particularly valuable when they are used to support high-speed rotors in precision machines. Gas-lubricated films are nearly isothermal, because the ability of the bearing materials to dissipate heat is greater than the heat-generating capacity of gas films, which have very low friction losses, so no thermal effects appear during gas bearing operation. These advantages of gas bearings are due to the fact that the surfaces of the journal and bush are separated by a gas (mainly air) layer characterized by a very low (compared with oil) viscosity. Gas bearings retain their advantages at high rotational velocities, which significantly exceed the maximum rotational velocities admissible for oil bearings and rolling bearings.