ULTRA-HIGH-SPEED TAPE-TYPE RADIAL FOIL BEARING FOR MICRO TURBOMACHINERY

This paper describes the design and test results of an ultra-high speed tape type radial foil bearing for turbo machinery. The outer and middle foil segments have some folds, where the section of the foil is made thinner by etching grooves. This automatically forms leaf springs just by wrapping the foil around a rotor three times. A foil bearing test rig with a shaft diameter of 8 mm was designed based on a design method developed in this study. The achieved maximum rotation speed was 642,000 rpm, corresponding to a DN product of 5,236,000. This is the highest DN product achieved by foil bearings to the best of our knowledge. The bearing performance showed no significant deterioration after 300 start-and-stop cycles.