Patent ID: 6991021
Filing Date: 2006-01-31
Classification: B22D,H02K

Abstract:
1. A process for the manufacture of an electric motor rotor, said rotor comprising: a lamination stack, which is provided with a central axial bore and a plurality of axial channels; and a cage formed by an upper end ring and a lower end ring, which are respectively seated against the upper and lower end laminations of the lamination stack, and interconnected, in a single piece, by a plurality of bars in the axial channels, comprising the steps of: filling the lower end of the central axial bore with a respective core; mounting, at the upper end portion of the central axial bore, a stamping pin, which has a widened head seated against the upper end lamination of the lamination stack and presents a circular contour with a diametrical cross section coinciding with the diametrical cross section of the central opening of the upper ring of the cage; heating the lamination stack at a first temperature that is lower than the melting temperature of a metal to be injected; heating, at said first temperature, an upper cavity of a mold, to be positioned close to the upper end lamination of the lamination stack and, at a second temperature substantially lower than the first temperature, a lower cavity of the mold, to be positioned close to the lower end lamination of the lamination stack; positioning the lamination stack, with its vertically disposed longitudinal axis, inside the mold; rotating the mold and pouring the molten metal to the inside thereof through an inlet channel, in order to fill the lower cavity, the axial channels, and the upper cavity; solidifying the metal, stopping the mold and opening it to remove the rotor and the core from the inside thereof, with the cage already formed and comprising the lower ring, the bars, and an upper plate that covers the stamping pin; and axially extracting the stamping pin in order to break, centrally, the upper plate, transforming the upper plate into the upper ring of the cage.