Hydrodynamic Lubrication Evaluation of Thrust Bearings

The pressure generation within the lubricant fluid present in the clearance between a thrust bearing and the collar attached to the shaft has a fundamental importance to avoid contact between solid parts with axial relative motion. Any existing contact can lead to friction, wear and, as a consequence, failure of elements on a rotating machine. Therefore, in order to design an effective bearing, it is important to know how the pressure is generated within the oil film and the magnitude of the load capacity transmitted from the collar to the bearing throughout the fluid. Thus, it is necessary to solve the Reynolds' Equation to obtain the distribution of pressure on the sections under Hydrodynamic Lubrication. Then several operational parameters can be obtained, such as, the total load capacity, lubricant fluid flow, position of the maximum pressure and so on. In order to evaluate this hydrodynamic lubrication problem, a numerical solution using the Finite Difference Method in polar coordinates was applied. Operational characteristics of several thrust bearings with different geometries were evaluated. The analysis allowed the comparison amongst the effects caused by the set of parameters involved, such as area of the flat part of the pad, film thickness and sector radii. Also the influence of the parameters on the results of the distribution of pressure and the calculated load capacity is evaluated, as well as the evaluation of the optimum dimensions for bearings and its influence on the component efficiency.