Estimation of gas film lubrication effects beneath sliding bushings of microrotors using a molecular gas film lubrication equation

Abstract Molecular gas film lubrication effects between rotor bushings and stators in micromotors with a spacing of less than 0.1 μm are numerically clarified using a molecular gas film lubrication equation based on the Boltzmann equation. In conventional bushings, positive pressures and negative pressures are generated nearly equally and the net sum, and hence the load-carrying capacity, is extremely small so it cannot support the rotor weight. A new bushing with a step produces a net pressure that results in a load-carrying capacity that exceeds the rotor's weight. Gas film lubrication effects considering surface roughness are briefly discussed on the basis of the mixed lubrication model.

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