Influence of the profile of longitudinal grooves of various depths on increasing static characteristics of radial gas bearings

Abstract

Radial gas bearings with one line for supplying compressed gas to the working gap with blind microgrooves of constant width and variable depth of the different profiles are considered. Such as with constant depth microgrooves; triangular or stepwise with decreasing depth of grooves along the course of compressed gas. For them, the radial lifting force, the recovery moment for angular displacements of shaft in the range of constancy of radial and angular stiffness and consumption of compressed gas for the bearing`s work are found. Calculations and studies have shown that a radial bearing with longitudinal microgrooves whose depth decreases linearly in the direction of gas flow has a large radial lifting force and a recovery moment for angular displacements of shaft compared to a bearing with microgrooves of constant depth. Bearings with stepped longitudinal microgrooves with greater depth at the entrance to working gap are operable in the range of practical use of bearings and have greater dimensionless radial and angular stiffness and are more economical compared to bearings with microgrooves of constant depth. In practical activities (when designing spindle units), it is not recommended to use gas bearings with a variable depth of microgrooves having a minimum depth at the entrance to working gap. With optimal design parameters, the flow rate of compressed gas for bearings with longitudinal microgrooves of different transverse profiles with alignment of shaft and sleeve is almost the same (the difference is about 7, 8%).