ROTOR FOR A UNIVERSAL ELECTRIC MOTOR AND RELATIVE METHOD AND APPARATUS FOR OBTAINING THE SAME

摘要

The present invention regards a rotor (10) of a universal electric motor comprising a commutator (14) and a rotor lamination stack (16) arranged coaxially with each other along a first axis (X-X), and at least a winding wire (22) obtained with a first conductive material and coated with an electrically insulating enamel. Said commutator (14) comprises a plurality of bars (18), obtained from a second conductive material, having ends facing said rotor lamination stack (16) each having a hook (20) for said wire (22) adapted to be moved between an initial open position and a final closed position. In particular, on the internal surface (20A) of each of said hooks (20) is obtained at least a first cutting (21) that is recessed with respect to the surface of the corresponding bar (18) and has a top opening (23) having a width (A) that is smaller than the diameter (D) of the wire (22) so that, when said hook (20) is displaced from the open position to the closed position, the edge portions (21C) of said opening (23) remove locally by friction and abrasion the electrically insulating enamel that coats said portion (24) of the wire (22) to allow the electrical connection between the wire (22) and the bar (18). The present invention also concerns a process for associating at least one hook (20) of a bar (18) of a commutator (14) to at least one portion (24) of wire (22) of a rotor winding, an apparatus (60) for obtaining a commutator of a rotor (10), and a process for obtaining a commutator of a rotor (10).