Abstract: A commutator for electric machines has a multiplicity of segments (2), which are provided with anchoring means (5) for securing in the insulating body (13), are joined at one end with associated winding ends (8) of a rotor, and are divided from one another in the circumferential direction by slots (10) which are filled with insulating material (15). The insulating material forming the insulating body (13) and filling the slots (10) as insulating lamellas (15) protrudes radially, in the form of widened supports (16), beyond the insulating lamellas (15). The supports (16) form the boundary in the circumferential direction for the terminal grooves (17) of the segments (2) for the rotor winding ends (8), which are welded to the segments (2).

Abstract: A method of making a commutator ring (2) for a commutator, which is provided with a plurality of commutator segments (7) with connection lugs (10) and anchoring means (44) and which is cold-formed by reduction and gauging in a single manufacturing step of a forming apparatus from a blank (1) with preformed segmental grooves (6) and a flange (4) which can subsequently be made into connection lugs. The forming apparatus is provided with a single or multi-stage, single or multi-part die. The blank is pressed against the die by radially disposed slides (39, 59) of the apparatus which are adjacent each commutator segment (7) and connection lug (10). Finally, during retraction of the die from the blank, the anchoring means (44) are formed on the commutator segments by a gauging apparatus being drawn through the tubular blank to "mushroom" inner teeth of the blank and shape them to form dovetail shaped anchors in a commutator hub sleeve.

Abstract: A method of forming flanged commutator segmental rings in a single power stroke by cold-extrusion which assures full formation of the inner ribs which become commutator segments, so that the segments will anchor well and resist centrifugal force at high rotational speed. The extrusion apparatus has an inner rib-forming die (18) and an outer ring-shaped flange-forming die (16). In the first stage of the power stroke, a ring-shaped blank (1) is formed into a flange precursor and a shaft portion (24) with inner ribs. In the second stage of the power stroke, the ring-shaped die (16) forms the flange (4) while the rib-forming die (18) forms a longer shaft (3) with a full complement of inner ribs (5) and a counter-punch (13) maintains pressure.

Abstract: To retain end portions (10,11) of armature conductors in slots (6, 37) formed in radially projecting lugs (5) of armature segments (2) of a commutator (1), the side walls of the slots are formed with a deviation from a plane surface, for example by a recess (7) or an inwardly extending projection (38), and the end portions (10, 11) of the windings are then placed in the slot and deformed under punch or stamping pressure to form, together with the recess or the region adjacent the projection, an interfitting projection-and-recess connection which will withstand high centrifugal forces, and prevent loosening of the connection under conditions of shock, vibration, high temperatures and temperature changes, to make the connection particularly suitable for installation in mobile, typically automotive dynamo electric machines.