High-vacuum pump having a bell-shaped rotor

Claim 1

A high-vacuum pump, comprising: a downwardly depending rotor (5) including a rotor bell land an axial, downwardly extending shaft, an upwardly extending stator (1, 6) supporting the rotor via axially spaced roller bearings (12, 13) located inside the rotor bell between the stator and the shaft, said stator defining a first pumping stage (7, 10) with an inner cylindrical surface (10) of the rotor and a second pumping stage (8, 9) with an outer cylindrical surface (9) of the rotor, at least the first pumping stage being of the Holweck type, a suction inlet (3) provided at an apex (4) of the rotor bell, and a discharge outlet (11) disposed proximate a lower rim of the rotor bell, said Holweck type first pumping stage defining a blind bore terminating at a closed upper end of the rotor bell and being configured to pump particles towards said rim to produce a higher vacuum in an interior space (15) in which the roller bearings are disposed than at the rim of the rotor bell, and said first and second pumping stages converging at outlet ends thereof proximate the discharge outlet.