Tech Lic. Transactions of Machine Elements Division. Lund 1996

Abstract:

The characteristics of a spherical hydrodynamic journal bearing with one axial groove are studied in applications with steady rotation. Numerical results are presented for a bearing configuration with the span angle 90° and with the oil groove located at the angles 90°, 180° and 270° upstream of the load line. The pressure distribution is solved with boundary conditions that ensure continuity of flow in the whole bearing by means of iterative Finite Element solutions according to a prescribed schedule.

The calculations show that the bearing can support axial loads up at least 40% of radial load. The axial stiffness is, however, much less than the radial stiffness.

For the cases at the angles 90° and 180°, the load carrying capacity is practically the same. In the case at the angle 270°, the load carrying capacity is reduced because the film thickness is small at the oil groove which reduces the flow in this case. The largest amounts of the flow are obtained with the load angle 180°.

For given load, speed and minimum allowed film thickness, optimum characteristics for minimum power loss have been established for given ratios between the axial and radial load up to at least 0.3. The power loss increase when this load ratio is increased while the load angle 90° gives the lowest power loss of the three cases studied.

Experimental studies show very good agreement with the theoretical results for large radial eccentricities.