Patent ID: 6342746
Filing Date: 2002-01-29
Classification: H01F,H02K

Abstract:
A device for producing rotary motion, comprising:a rotor assembly including a shaft which defines an axis of rotation for the assembly, a rotor mounted on the shaft for rotation therewith, the rotor having a plurality of rotor extension portions circumferentially-spaced and extending in a radial outward manner away from the shaft; a stator assembly circumferentially surrounds at least a portion of the rotor which includes the rotor extension portions, the stator assembly including: (a) at least two spaced permanent magnets, each having north and south pole faces, the north pole faces being in substantial alignment on opposite sides of the rotor assembly and the south pole faces being in substantial alignment on opposite sides of the rotor assembly, (b) at least one north-field pole piece, comprising: (i) a first magnet face positioned adjacent to the north pole face of a first permanent magnet, (ii) a second magnet face positioned adjacent to the north pole face of a second permanent magnet, (iii) at least one first north-field stator extension and at least one second north-field stator extension, wherein the first and second north field stator extensions are separated from each other by a north-field bridge portion, and wherein both of the first and second north-field stator extensions extend toward the rotor; (iv) said north-field bridge portion positioned between the first and second north-field stator extensions; and, (v) a north-field control coil, surrounding the north-field bridge portion positioned between the first and second north-field stator extensions, and having a predetermined number of turns to allow the north-field control coil, as alternating voltage is applied to it in a cyclical manner, to direct essentially all of the north magnetic field emanating from the north faces of both the first and second permanent magnets, through each of the first and second north-field stator extensions, in an alternating manner which is coordinated with rotation of the rotor; (c) at least one south-field pole piece, comprising: (i) a first magnet face positioned adjacent to the south pole face of a first permanent magnet, (ii) a second magnet face positioned adjacent to the south pole face of a different permanent magnet, (iii) at least one first south-field stator extension and at least one second south-field stator extension, wherein the first and second south field stator extensions are separated from each other by a south-field bridge portion, and wherein both the first and second south-field stator extensions extend toward the rotor; (iv) said south-field bridge portion positioned between the first and second south-field stator extensions; and, (v) a south-field control coil surrounding the south-field bridge portion positioned between the first and second south-field stator extensions, and having a predetermined number of turns to allow the south-field control coil, as alternating voltage is applied to it in a cyclical manner, to direct essentially all of the south magnetic field emanating from the south faces of both the first and second permanent magnets, through each of the first and second south-field stator extensions, in an alternating manner which is coordinated with rotation of the rotor; and, means for connecting each of the north-field and south-field control coils to a source of electric energy and a switching means which, in combination, are capable of energizing the north-field and south-field control coils in a predetermined timed manner correspond to positions of the plurality of circumferentially-spaced outwardly-extending portions of the rotor during rotation thereof.