Nominal Clearance of the Foil Bearing

Classic lubrication theory has generally been directed toward fluid films bounded by solid objects that were assumed to be infinitely rigid. This assumption, however, is contrary to the physical nature of things. Blok and van Rossum
¹
introduced the concept that the rigid bearing could be replaced with a perfectly flexible band. This configuration has been termed the foil bearing. It represents the other extreme situation. Between these limits then are the cases of practical engineering interest. The hydrodynamic air lubrication of magnetic tape over magnetic heads, to prevent contact and wear, closely approximates the foil bearing. From the viewpoint of engineering design there is a great deal of interest in this configuration. The parameters of the foil bearing discussed in this Communication are shown in Fig. 1.