Friction characteristic of H-type hydrodynamic gas bearing for gyroscope motor during start-up

In order to reduce the friction and wear of H-type hydrodynamic gas bearing for gyro motor during start-up, a theoretical model with considering the roughness contact and lubrication is built for the study of the bearing friction characteristic. First, the starting position and starting torque of the bearing shaft are determined by calculating the elastic deformation of the rough sleeve surface under the gravity effect. Then, by simultaneously solving the surface rough contact & lubrication equations and the rotor's 5-DOF motion equation, the load capacity, trajectory and contact area during start-up are obtained, and the lift-up time and speed of the shaft are determined by reducing the contact area to 0. Finally, the influences of surface roughness and geometric parameters on the bearing performance are studied. The experiment results show that: the lift-up speed and the wear zone can be decreased by reducing the standard deviation of rough surface peak heights; with the increase of the groove width ratio, the lift-up speed increases and the wear zone decreases; the lift-up speed and wear zone have the minimum values at the groove depth of 1.0 μm and 2.0 μm respectively. © 2019, Editorial Department of Journal of Chinese Inertial Technology. All right reserved.