Flux focusing arrangement for permanent magnets, methods of fabricating such arrangements, and machines including such arrangements
Numerous arrangements for permanent magnets are disclosed that can focus the flux produced by the magnets. Depending on the particular application in which the disclosed designs and techniques are used, efficiency and reliability may be increased by minimizing flux leakage, increasing peak flux density, and shaping the flux fields to improve the effective coercivity of the flux focusing permanent magnet arrangement when loaded, and to achieve customized voltage and current waveforms. The disclosed magnet assemblies may be incorporated into a machine, such as a motor/generator, having windings and may be disposed for movement relative to the windings. The magnet assembly may be mounted on a support formed of one or more ferromagnetic materials, such as a back iron. The disclosed flux focusing magnet assemblies may be formed using a variety of manufacturing methods.
1. An apparatus comprising:
a stator; and
a rotor disposed for movement relative to the stator and including:
a backing member formed of a ferromagnetic material; and
a flux focusing magnet assembly attached to the backing member, the flux focusing magnet assembly including:
a center portion having a nominal flux axis directed away from the backing member;
a first side portion disposed on the backing member on a first lateral side of the center portion and having a nominal flux axis oriented to be non-parallel with and oriented towards the nominal flux axis of the center portion in a direction away from the backing member;
a second side portion disposed on the backing member on a second lateral side of the center portion, opposite to the first side portion, and having a nominal flux axis oriented to be non-parallel with and oriented towards the nominal flux axis of the center portion in a direction away from the backing member,
the first side portion and the second side portion configured to direct flux toward the center portion;
a first end portion disposed on the backing member on a first longitudinal end of the center portion and having a nominal flux axis oriented to be non-parallel with and oriented towards the nominal flux axis of the center portion in a direction away from the backing member; and
a second end portion disposed on the backing member on a second longitudinal end of the center portion, opposite to the first end portion, and having a nominal flux axis oriented to be non-parallel with and oriented towards the nominal flux axis of the center portion in a direction away from the backing member.
2. The apparatus of claim 1 , wherein the nominal flux axes of the center portion, the first side portion and the second side portion are approximately coplanar in a first plane, and the nominal flux axes of the center portion, the first end portion and the second end portion are approximately coplanar in a second plane, approximately normal to the first plane.
3. The apparatus of claim 1 , wherein the nominal flux axes of the center portion, the first side portion and the second side portion are approximately coplanar.
4. The apparatus of claim 1 , wherein the flux focusing magnet assembly further includes a ferromagnetic lens operatively engaged with at least the center portion.
5. The apparatus of claim 1 , wherein at least one of the central portion, the first side portion, and the second side portion has a rating for at least one of energy product, magnetic remanence, operating temperature, and coercivity that is different than a rating for at least one other of the central portion, the first side portion and the second side portion.
6. The apparatus of claim 1 , wherein:
the rotor has a first portion disposed on a first side of the stator and a second portion disposed on a second, opposite side of the stator; and
the magnet assembly is a first magnet assembly, is disposed on the first portion of the rotor, and has a nominal flux direction oriented towards the stator, and further comprising:
a second magnet assembly disposed on the second portion of the rotor, positioned opposite to the first magnet assembly, having the same construction as the first magnet assembly, and having a nominal flux direction oriented away from the first magnet assembly.
7. The apparatus of claim 1 ,
wherein the magnet assembly is a first magnet assembly, the nominal flux direction is oriented away from the backing member, and further comprising a second magnet assembly disposed on the backing member adjacent to the first magnet assembly, having the same construction as the first magnet assembly, and having a nominal flux direction oriented towards the backing member.
8. The apparatus of claim 1 , further comprising a ferromagnetic insert disposed between the first magnet assembly and the second magnet assembly and in operable engagement with the adjacent side magnet of each magnet assembly.
9. The apparatus of claim 1 , wherein each of the central portion, the first side portion, and the second side portion is a discrete magnet.