Influence of Atmospheric Pressure Supplied on Permittivity of Air-film of Aerostatic Bearing

摘要

Influence of atmospheric pressure supplied on permittivity of the air-film is researched based on the capacitive testing method of the air film thickness of aerostatic bearing.An experiment platform is designed.The experimental results illustrate that permittivity has significant negative correlation with atmospheric pressure which varies from 0.1MPa to 0.48MPa when other environmental conditions remain unchanged.The curves conform to the fourth-order polynomial approximately.All of the values of R2 are beyond 0.944 which means that trend lines fit the data curves well.Relative permittivity of the air film is between 0.996 and 1.324.This interval shows that weak current exists between restrictor and flat of the experiment which are not absolutely insulating and atmosphere of the air film is not pure.This result provides a basis both for establishing accurate mathematical model of air film thickness and capacitance value of the aerostatic bearing and for other exploratory experiments later.