Study on characteristics of porous ceramic gas bearings.

Porous gas bearings show high load capacity and bearing stiffness. Conventional metal sintered porous gas bearings are the surface choked type and there are some difficulties in controlling gas permeability. Recently, porous ceramics with low and homogeneous permeability can be easily obtained and machined with high accuracy without any surface chok-ing. In this paper, analysis of porous ceramic gas bearings are presented and steady state characteristics are calculated for the cases of externally pressurized, self acting, and hybrid type operation. Pressure distribution in porous ceramics is also calculated when the surface is slightly choked to improve pneumatic hammer instability.