Externally pressurized air bearing is widely used in high speed spindle system and high precision sliding system because of its advantages such as low friction, low heat generating characteristics and averaging effect of the pressure deviation in the air film of the bearing. Thrust air bearing with a diaphragm has high load capacity and high stiffness, though its characteristics are subjected to the thickness and Young's modulus of diaphragm. So, the characteristics of externally pressurized air bearings with a variable-gap-diaphragm are studied both theoretically and experimentally to forecast the diaphragm thickness to which the bearing characteristics are not subjected and to improve the load capacity and stiffness.
Theoretical method adopting diaphragm which is fixed at inlet hole is proposed. Piezoelectric actuator is used for the purpose of making variable-gap geometry of a diaphragm. It is shown that the theoretical method proposed in this thesis can forecast the load capacity and stiffness successfully and that the externally pressurized thrust air bearing with a variable gap diaphragm is useful for the purpose of increasing load capacity and stiffness.
