Patent ID: 8575813

Claim:
A rotor core, for an induction motor, comprising: a body that at least: extends radially inward from an outer surface of the body toward a central axis; extends axially from a first axial end to a second axial end; and defines a plurality of internal grooves; wherein each of the internal grooves at least: includes an opening, having an opening profile width, at the outer surface of the body; is defined by two opposing walls; extends from the first axial end to the second axial end; extends radially between the opening at the outer surface and a radially-inward end; and includes a body section; and wherein the two opposing walls comprise: opposing first straight and parallel segments extending radially inward, from the opening, forming a neck portion having a neck profile width equivalent to the opening profile width; opposing second straight and parallel segments extending radially inward, from the neck portion, forming a first primary portion having a first primary profile width being greater than the neck profile width; opposing extended segments, extending radially inward from the first primary portion, forming an extended portion having an extended profile width being greater than the first primary profile width; opposing curved segments meeting at the radially-inward end, forming an inward-end portion of the groove; and opposing third straight and parallel segments extending radially between the inward-end portion and the extended portion, forming a second primary portion, having a second primary profile width equivalent to the first primary profile width.