Operating Characteristics of Three-Lobe Bearings

Abstract

Three-lobe bearings were studied for both rigid and flexible rotors from three aspects: instability threshold, load carrying capacity, and unbalance response. Offset factor, preload factor, and load orientation were parametrically varied for the bearings and their influences on the foregoing characteristics were studied both theoretically and experimentally. Results indicate that, in general, all three operating characteristics cannot be optimized for the same bearing parameters. For example, the lowest unbalance response was found for small bearing preload factors, while the highest instability thresholds were found for large preload factors. As a result, when choosing a bearing for a particular application, the designer must consider which operating characteristic is most important and choose the bearing accordingly.