Patent ID: 6861778

Claim:
A rotary mechanism comprising a stator body with an inner wall defining a chamber having an axis and enclosing a liquid and having opposed ends disposed coaxially with said chamber, an elongated rotor having opposed first and second ends and being operationally disposed within said chamber and having a rotor axis defining an axis of rotation, magnetic driven means disposed on said elongated rotor and being positioned radially outwardly of said rotor axis generally medially of said first and second ends, electromagnetic drive means coupled to a source of energy and arranged along said stator body to deliver rotational driving energy to said rotor through said magnetic driven means; said rotor comprising; (a) a rotor body having a relative density substantially less than that of said chamber liquid; (b) a configuration defining an elongated surface of revolution with an axial length defined between said first and second ends; and with a diameter of said rotor body transverse to said axis of rotation being selected to provide a clearance between an outer surface of said rotor body and the inner wall of said stator body; (c) said rotary mechanism having a plurality of passive magnetic bearing pairs, each bearing pair consisting of first and second magnetic bodies in mutually magnetically coupled relationship with the first magnetic bodies of each bearing pair being mounted on said elongated rotary body and with the second magnetic bodies of each bearing pair being mounted along the inner wall of said stator disposed adjacent to and in magnetically coupled relationship with respective first magnetic bodies to form said bearing pairs; (d) each of said first and second magnetic bodies solely comprising a permanent magnet; (e) each of said first and second magnetic bodies comprising each of said passive magnetic bearing pairs being polarized and positioned in mutually attracting or mutually repelling relationship so as to function as radial and/or thrust bearings; (f) said plurality of passive magnetic bearing pairs being further arranged to form a passive suspension means for said elongated rotary body within said stator body, with said suspension means having negative stiffness only in directions perpendicular to the axis of rotation; and (g) said negative stiffness being of a magnitude such that centrifugal forces developed during rotation of said rotary body overcome said negative stiffness and create positive stiffness of said rotor suspension in all required degrees of freedom.