With the successful finalisation of the AiF–BMWK-funded research project “ Journal bearing system tolerances“, coordinated by the FVA, IKAT was able to demonstrate the correlation between geometric deviations and changes in the nominal operating parameters of the journal bearing. The main part of the investigations was a wide-ranging parameter variation in which form and tilting deviations were combined with a wide variety of load parameters on the hydrodynamic cylindrical journal bearing. For each of the variations, an operating point change could be assigned to the geometric change (deviation) by hydrodynamic simulation. The results of the parameter study were summarised in a tolerancing tool, which enables complete geometric tolerancing for the cylindrical functional surfaces of the bearing seat and the bearing of two bearing positions.
The results were validated on the 30mm and 110mm bearing test rig. The picture shows the lubricant film pressure field measured with the test rig and resulting from the geometric deviation, which was compared with the pressure distribution from the simulation.
In order to ensure an universal application of the journal bearing tolerance tool, the mathematical description of the described parameter field is to be carried out in a follow-up project. In this case, dimensionless key indicators will be used, which should make such a universal description possible.