Patent ID: 8629590

Claim:
A rotor for an electric motor of the type with an internal stator, the rotor comprising a carrier structure including a disc portion to which is centrally connected a shaft, and the periphery of the disc portion is joined to an essentially cylindrical annular skirt portion which in use extends coaxially around the stator; wherein the disc portion of the carrier structure has a plurality of slots between which there is defined a corresponding plurality of spokes, at least some of the spokes have, in a circumferential direction, a transverse cross-section shaped in a manner such to induce, at least when the rotor rotates in one direction, an at least approximately axial air flow through corresponding slots, the transverse cross-section has an internal or external surface which has a plurality of arc surface sections with different curvature, the arc surface sections extending continuously in a circumferential direction of the disc portion, adjacent arc surface sections of each transverse cross-section being connected together continuously.