Patent ID: 6866488

Claim:
A molecular drag vacuum pump, comprising: a housing defining an inlet and an outlet; a rotor rotatably carried within the housing, having an axis of rotation and a plane of rotation; at least one gas passageway, disposed in the housing between the inlet and the outlet and adjacent the rotor, configured to facilitate flow of a gas from the inlet to the outlet and to impart kinetic energy to the gas through contact of the gas with a moving surface of the rotor; and a slotless, brushless, permanent magnet motor integrally incorporated in the rotor and the housing, said motor comprising: a plurality of permanent magnets disposed in the plane of rotation in the rotor, the permanent magnets comprising a motor rotor element; and two sets of coils, symmetrically disposed in the housing above the rotor and below the rotor adjacent the permanent magnets of the rotor and in a plane substantially parallel to the plane of rotation of the rotor, the coils comprising a motor stator element, configured to have current therein electronically switched by an external switching circuit, so as to provide a force which turns the rotor within the housing.