PhD. Transactions of Machine Elements Division. Lund 1988

Abstract:

The oil lubricated combined hydrodynamic and hydrostatic bearing has been studied. The variation of oil viscosity with pressure and temperature has been considered when solving Reynolds' equation. Perturbation analysis has been employed in the investigation of dynamic stability for a linearized equation of motion of the journal center.

It has been found that without losing its load capacity under heavy load, a combined journal bearing can operate steadily at high speed under zero external load. The ideal pump power loss is normally very small compared to the total power loss.

Experimental investigations have been carried out. The agreements between the experimental results and the theoretical ones are rather good. The experiments also show that with 10 % of critical speed as a margin, the stability conditions obtained for small oscillations can be applicable for big amplitude vibrations as well.