Abstract: A single-ended turbomolecular vacuum pump operable in the free molecular flow pressure range having an improved bearing assembly located between the motor and the pump rotor discs is disclosed. The improved bearing assembly which is of the "plain" or "sleeve" liquid lubricated type with the bearing surfaces has a relatively high ratio of journal diameter to bearing axial length and includes lubricant ports radially disposed about both the centers of the bearing and the journal. The improved bearing assembly is characterized by improved heat transmission capabilities, high tolerance for misalignment, long life and significant reduction of pump vibration.

Abstract: A single ended turbomolecular vacuum pump operable in the free molecular flow pressure range having an improved bearing assembly between the motor rotor and the pump rotor discs is disclosed. The improved bearing assembly which is of the "plain" or "sleeve" liquid lubricated type has a relatively high ratio of journal diameter to bearing axial length. The improved bearing assembly is characterized by improved heat transmission capabilities, high tolerance for misalignment and long life.