An active non-contact journal bearing with bi-directional driving capability utilizing coupled resonant mode

Non-contact journal bearings are conventionally based on pressurized air or magnetic levitation. This paper reports on a new design of an active non-contact journal bearing with bi-direction driving capabilities. It combines the functions of an axis positioner, non-contact journal bearing, and rotary motor utilizing coupled vibration modes. The shaft levitation is achieved by creating a stable air film using near-field acoustic force; while the non-contact rotation is realized by controlling the pressure distribution within the air film using coupled resonant mode. The essential design methodology and theoretical principles are presented along with the performance evaluation of the functional prototypes.