A bump foil journal bearing is a prospective applicant that can support a small-sized rotor of high-speed rotary machinery. However, a theoretical model that can make a reasonable prediction of the bearing performance has not been developed. The authors have predicted the maximum load carrying capacity of the bearing by using two model bearings, one of which corresponds to the bearing with an excessive static fiction between the top and the bump foils and the other to the bearing without the friction. However, the top foil could not lift off the bump foil in the model bearings. In this report, the effect of lifting of top foil and also mounting style of top foil on the bearing housing on the predicted capacity will be investigated. It is found that their effect is little when excessive static friction is acted between the two foils. This results from their negligible influence on the distribution of air film pressure. On the other hand, the effect is also little when the friction is negligible. This is because only a slight change in the reaction force of air film arises although they affect the pressure distribution through a larger deformation of top foil.
展开▼
