Method of making commutator rings

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. The die serves as an ejector for the finished commutator ring during its return movement to its initial position. After assembly to the commutator hub sleeve, the remaining connecting elements (8, 11) which held the commutator segments and connection lugs in closed, ring shape are removed or severed.