A self-acting thrust bearing for high speed micro-rotors

A self-pressurizing hydrodynamic thrust bearing has been designed, fabricated and tested up to speeds of 450,000 rpm on a 4.2 mm diameter MEMS radial inflow turbine. This test device demonstrated the load bearing capability predicted by the macro-scale gas bearing theory derived from the literature. The design of the devices tested was compromised to fit an existing geometry and fabrication sequence. Given more design freedom, these bearings should be capable of operating at several million rpm. Compared to existing hydrostatic thrust bearings, a hydrodynamic approach offers significantly simplified fabrication and elimination of the need for a source of pressurized gas external to the bearing.