Experimental Study on the Effect of Top Foil Sagging on the Performance of Thrust Foil Bearing

The effect of top foil sagging on the static characteristics of gas thrust foil bearings is investigated.A gas thrust foil bearing test rig is built.Four top foils with different thicknesses of 0.10 mm,0.15 mm,0.20 mm,and 0.30 mm are selected,and bearing load capacity,friction torque and top foil deformation in taper area are measured.Test results showed that under the same external load,the top foil deformation decreases with increase of top foil thickness,which can make hydrodynamic pressure distribution on the top foil more uniform and reduce the friction torque of the bearing.However,when the thickness of top foil reaches more than 0.2 mm,the top deformation of taper area no longer decreases obviously and the friction torque increases.Therefore,it is inappropriate to use top foils with the thickness of about 0.20 mm in engineering application.