GB1496445A - Bar windings for electrical machines - Google Patents

Abstract

1496445 Bending; shearing; making electrical coils NI I EXPERIMENT INST AVTOMOBIL ELECKTRO I AVTOPRIB 26 March 1975 12742/75 Headings B3E B3A and B3W [Also in Division H2] A single turn bar winding made from wire of rectangular section, and comprising two substantially parallel legs 3 connected by an end portion 2, is formed by bending the wire in the plane of the shorter side face of the wire, the end portion also being bent without being twisted so as to be depressed asymmetrically out of the plane of the winding. Fig. 2 shows apparatus for performing the bending in three stages. The wire is fed by a reciprocating gripper device comprising a carriage 16 movable on rods 19, and a slide 17 movable by piston and cylinder 18 and connected to the carriage by pins 23, and slotted levers 22 mounted on rotary discs 21. These discs also actuate reciprocable spring loaded plunger 24 for gripping the wire. On the extension stroke of cylinder 18, the carriage is initially held by brakes (not shown) so that the slide advances and rotates the levers 22 and discs 21 and the wire is gripped by plungers 24. Thereafter the slide moves the carriage against its brakes, to feed the wire until the carriage abuts stops 20. On the return stroke, the wire is released by the plungers, and return of the wire is prevented by device 25, 26. A storage loop of wire is maintained by a loop size sensor 14 operating limit switches 15 which turn feed motor 5 on and off. The wire also passes through cold working device 11 and straighteners 12, 13. The advanced wire, passes through guides 27 to abut a stop 28, and is cut off by dies 29, 30 shaped so as to taper the wire ends in two planes as seen in Fig. 1. Die 34 then descends on to die 32, asymmetrically shaping' what is to become the end portion of the winding in the plane of the broader faces of the wire. Die 35 then advances to bend the end section into the V-shaped leading portion of a groove 33, then dies 35 and 38 are moved together, past a yoke 36 which presses the leg portions of the winding into the remainder of groove 33. A final shaping of the end portion is achieved by die 38, which has a hook to remove the winding from die 32.