Large diameter radial magnetic bearing

Claim 2

A large diameter radial magnetic bearing comprising an inner rotor having an axis of rotation and including a central shaft having an outer periphery, and a stack of ferro-magnetic laminations mounted on said shaft at said outer periphery; and an outer stator comprising a plurality of electromagnets including poles disposed in facing relation to the stack of ferromagnetic laminations on the rotor, said stack of ferromagnetic laminations comprising a plurality of very thin individual lamination segments each extending over a limited angular sector around the periphery of the central shaft, said laminations being distributed in parallel planes to constitute a succession of flat split rings extending peripendicularly to the axis of the rotor, the individual lamination segments in a given plane being offset angularly relative to the individual lamination segments of adjacent planes to provide a staggered stack of laminations, said central shaft having longitudinally extending grooves in the outer periphery thereof, said individual laminations segments including projecting portions which engage in said grooves in the central shaft, said grooves being separated from one another at a pitch of about 9°.

Claim 3

A large diameter radial magnetic bearing comprising (a) an outer rotor having an axis of rotation and including a central shaft having an outer periphery, and a stack of ferromagnetic laminations mounted on said shaft at said outer periphery, said stack of ferromagnetic laminations comprising a plurality of very thin individual lamination segments each extending over a limited angular sector around the periphery of the central shaft, said laminations being distributed in parallel planes to constitute a succession of flat split rings extending perpendicularly to the axis of the rotor with the individual lamination segments in a given plane being offset angularly relative to the individual lamination segments of adjacent planes to provide a staggered stack of laminations, said central shaft being provided with anularly spaced longitudinally extending grooves in said periphery, said individual lamination segments each including complementary projecting portions which engage in said grooves in the central shaft, whereby the individual lamination segments are mounted on said central shaft of the rotor solely by the assembly of the projecting portions in the complementary grooves and (b) an outer stator comprising plurality of electromagnets including poles disposed in spaced facing relation with said stack of ferromagnetic laminations on the rotor.

Claim 4

A large diameter radial magnetic bearing comprising (a) an outer rotor having an axis of rotation and including a central shaft having an outer periphery, and a stack of ferromagnetic laminations mounted on said shaft at said outer periphery, said stack of ferromagnetic laminations comprising a plurality of very thin individual lamination segments each extending over a limited angular sector around the periphery of the central shaft, said laminations being distributed in parallel planes to constitute a succession of flat split rings extending perpendicularly to the axis of the rotor with the individual lamination segments in a given plane being offset angularly relative to the individual lamination segments of adjacent planes to provide a staggered stack of laminations, said central shaft being provided with anularly spaced longitudinally extending grooves in said periphery, said individual lamination segments each including complementary projecting portions which engage in said grooves in the central shaft, whereby the individual lamination segments are mounted on said central shaft of the rotor solely by the assembly of the projecting portions in the complementary grooves and (b) an outer stator comprising plurality of electromagnets including poles disposed in spaced facing relation with said stack of ferromagnetic laminations on the rotor.

Claim 5

A magnetic bearing as claimed in claim 2, wherein the projecting portions of said individual lamination segments are of T-shape.

Claim 6

A magnetic bearing as claimed in claim 2, wherein the projecting portions of said individual lamination segments are of a dovetail shape.

Claim 7

A magnetic bearing as claimed in claim 2, wherein each of said individual lamination segments to extend over an angular sector of about 30° around the periphery of the central shaft.

Claim 8

A magnetic bearing as claimed in claim 2, wherein in each said plane of laminations there are ten individual lamination segments each extending over an angular sector of 36° around the periphery of the central shaft.

Claim 9

A magnetic bearing as claimed in claim 2, wherein the stack of laminations comprises about one hundred individual lamination segments disposed in parallel planes.

Claim 10

A magnetic bearing as claimed in claim 2, wherein each individual lamination segment is about 0.1 mm thick.

Claim 11

A magnetic bearing as claimed in claim 2, wherein adjacent individual lamination segments in each plane form gaps therebetween of a width less than a few tenths of a millimeter.

Claim 12

A magnetic bearing as claimed in claim 2, wherein said rotor has an outside diameter greater than about one meter.

Claim 13

A magnetic bearing as claimed in claim 2 wherein said individual lamination segments have smooth ungrooved outer peripheral surfaces which, in each plane, are aligned to form a smooth substantially continous ungrooved outer surface for the split ring in said plane.

Claim 14

A magnetic bearing as claimed in claim 11 wherein said projecting portions of said individual angular segments project radially inwards into said complementary grooves and are comprised of end projecting portions spaced from respective lateral edges of each individual angular segment and intermediate projecting portions between said end projecting portions.

Claim 15

A magnetic bearing as claimed in claim 2 wherein the individual lamination segments in each plane defines an outer surface which faces said poles in spaced relation defines.