RADIAL MULTI PIECE ROTOR FOR ELECTRIC MACHINE
A permanent magnet carrier, which could be a rotor or stator of an electric machine, includes a first non-magnetic ring and a second non-magnetic ring. Between the rings are soft magnetic pole elements. The soft magnetic pole elements each connect to the first and second non-magnetic rings and the soft magnetic pole elements are separated from each other by the first and second non-magnetic rings. Permanent magnets are disposed between the soft magnetic pole elements.
1 . A permanent magnet carrier comprising:
a non-magnetic ring;
soft magnetic pole elements, the soft magnetic pole elements each connecting to the non-magnetic ring and the soft magnetic pole elements separated by the non-magnetic ring; and
permanent magnets disposed between the soft magnetic pole elements,
wherein the soft magnetic pole elements are each fitted in a single receiving slot in the non-magnetic ring to engage the soft magnetic pole elements to the non-magnetic ring; and
wherein the permanent magnets are radially tapered.
2 . The permanent magnet carrier of claim 1 in which the magnetic pole elements are shaped to restrain the magnets from motion in a radially outward direction.
3 . The permanent magnet carrier of claim 1 , in which the soft magnetic pole elements define slots between the magnetic pole elements shaped to accommodate the tapered permanent magnets.
4 . The permanent magnet carrier of claim 1 in which the non-magnetic ring is positioned radially inward of the magnets.
5 . The permanent magnet carrier of claim 4 , in which the non-magnetic ring is a portion of a hub.
6 . The permanent magnet carrier of claim 4 , wherein the non-magnetic ring is secured to the soft magnetic pole elements with glue.
7 . The permanent magnet carrier of claim 1 , where the non-magnetic ring is metallic.
8 . The permanent magnet carrier of claim 7 , in which the non-magnetic ring is aluminum or titanium.
9 . The permanent magnet carrier of claim 1 , in which the receiving slots provide a clearance fit for receiving the ends of the soft magnetic pole elements.
10 . The permanent magnet carrier of claim 1 in which the soft magnetic pole elements each comprise a single projection which is fitted in a respective one of the receiving slots in the non-magnetic ring.
11 . The permanent magnet carrier of claim 10 in which the projections are bosses.
12 . The permanent magnet carrier of claim 1 , wherein the receiving slots provide a clearance fit for receiving the bosses of the soft magnetic pole elements.
13 . A rotor for an electromagnetic machine comprising the permanent magnet carrier of claim 1 .
14 . A method of constructing a permanent magnet carrier, the method comprising:
assembling soft magnetic pole elements with a non-magnetic ring by fitting each of the soft magnetic pole elements in a single receiving slot in the non-magnetic ring; and
inserting radially tapered magnets between the soft magnetic pole elements.
15 . The method of claim 14 , wherein contacting the non-magnetic ring with the soft magnetic pole elements comprises fitting the soft magnetic pole elements in receiving slots in the non-magnetic ring to engage the soft magnetic pole elements to the non-magnetic ring.
16 . The method of claim 14 , wherein an assembly of the non-magnetic ring and the soft magnetic pole elements is created before the permanent magnets are inserted.
17 . The method of claim 14 , wherein assembling the soft magnetic pole elements with the non-magnetic ring comprises axially inserting each of the soft magnetic pole elements into the respective single receiving slot.