Patent ID: 8779638

Claim:
A rotor for a wet rotor electric motor comprising: a plurality of permanent magnets; a polymeric retaining sleeve, formed prior to the manufacture of the rotor, that comprises a generally cylindrical portion having an inner peripheral surface concentric about a central axis and a plurality of retaining partitions extending inward from the inner peripheral surface of the generally cylindrical portion, wherein the magnets are within the retaining sleeve at locations inward of the inner peripheral surface of the retaining sleeve and between retaining partitions such that the magnets are arranged angularly about the central axis, and wherein the retaining partitions are configured to at least substantially limit movement of the magnets toward the central axis; and a stainless steel shaft substantially co-axial with the central axis and operatively attached to the retaining sleeve containing the plurality of magnets with overmolded plastic, which also, in conjunction with the retaining sleeve, encapsulates the magnets; and wherein the rotor does not contain a ferromagnetic core between the shaft and the magnets.