Miniature turbomolecular pump

摘要

The present invention provides a very compact, lightweight, turbomolecular pump for evacuating a chamber at volumetric flowrates of less than 10 liters per second. In one embodiment a turbomolecular pump is provided having a bladed rotor disposed within a housing, and mounted for rotation at one end on a passive magnetic main bearing and at the other end on a ball bearing. The pump is configured such that the magnetic bearing carries a majority of the rotor unbalance load. The rotor may be beneficially tapered from a larger diameter at the high vacuum end to a smaller diameter at the low vacuum end. The invention also provides a method of machining the blades of the rotor from a rotor blank using a single point tool in a two-step numerical control lathe operation. In another method of the invention, the rotor blades are individually cut using a high speed circular slitting saw by plunging the saw radially into the rotor blank.