Permanent magnet laminated rotor with conductor bars

Claim 1

A permanent magnet rotor including a shaft rotatable about an axis, at least one set of a plurality of rotor laminations of magnetic material mounted on said shaft in stacked relation for rotation therewith, each of said rotor laminations having a plurality of substantially rectangular magnet apertures therein in a selected arrangement, a substantially rectangular high performance permanent magnet disposed in each of said magnet apertures, each of said magnet apertures having one end closer to said shaft than its other end, at least one holding lamination at each end of each set of said plurality of rotor laminations to retain said magnets within said magnet apertures, each of said holding laminations being formed of a non-magnetic material and being mounted on said shaft for rotation therewith, each of said magnets being magnetized across its thickness and having a length extending through the set of said plurality of rotor laminations greater than its thickness, means to retain said plurality of rotor laminations and said holding laminations together in stacked relation, said retaining means including a plurality of separate means extending through all of said plurality of rotor laminations and said holding laminations substantially parallel to the axis of said shaft and being spaced from each of said magnets and from the periphery of each of said plurality of rotor laminations and each of said holding laminations, each of said plurality of rotor laminations having a plurality of conductor bar apertures around at least substantially the entire periphery thereof, each of said holding laminations having a plurality of like conductor bar apertures around the entire periphery thereof, and metallic conductor means extending through each of said conductor bar apertures in each of said plurality of rotor laminations and the corresponding of said conductor bar apertures in each of said rotor laminations, each of said magnet apertures having its end furthest from said shaft overlapping with at least one of said conductor bar apertures in each of said holding laminations so as to be in communication therewith, said rotor including at least two sets of said plurality of rotor laminations, each of said sets of said plurality of rotor laminations being separated from each other by at least one of said holding laminations, and said retaining means retaining said sets of said plurality of rotor laminations and said holding laminations together in a stacked relation, the rotor in which four of said magnets are mounted in each of said sets of said plurality of rotor laminations, said four magnets in each of said sets of said plurality of rotor laminations being mounted the same so as to be aligned with said four magnets in each of the other of said sets of said plurality of rotor laminations, said four magnets being symmetrically disposed about the axis of said shaft, each of said four magnets having one end closer to said shaft than its other end, one pair of said four magnets being disposed to cooperate with each other to produce a total magnetomotive force, each of said magnets of said one pair of magnets having one face facing the periphery of each of said plurality of rotor laminations and its other face facing the adjacent face of the other of said one pair of magnets, said one pair of magnets having its adjacent faces of opposite polarity, the other pair of said four magnets being disposed to cooperate with each other to produce magnetomotive forces, each of said magnets of said other pair of magnets having one face facing the periphery of each other of said plurality of rotor laminations and its other face facing the adjacent face of the other of said other pair of magnets, said other pair of magnets having its adjacent faces of opposite polarity, each magnet of said one pair of magnets having its outer face of the same polarity as the outer face of the adjacent magnet of said other pair of magnets, means disposed between the one end of said one pair of magnets and the one end of said other pair of magnets and between the one end of the other of said one pair of magnets and the end of the other of said other pair of magnets to reduce flux leakage therebetween, and each of said magnets having its other end in contact with said metallic conducting means in one of said conductor bar apertures.