Ultrasonic head for welding armature wires to segments of collector - has peripheral recesses which mate with each segment as components are rotated in mesh with reciprocating action of electrode

摘要

To connect an insulated armature winding wire (12) with the armature segment (14) and ensure a conductive connection, a loop is usually placed over a hook (18), which is then folded back. The connection, in this case, is made using ultra-sonic welding techniques and a specially shaped electrode, in contact with the collector (10). This electrode (sonotrode) is cylindrical (22), and has a number of recesses (24) spaced at regular intervals around its periphery, so formed, that when in contact with the collector (10), the segments (14) mate with these recesses as the two components (22,16) are rotated, (in a similar manner to a pair of gears in mesh). The hooks (18) are thus under a high pressure, when the segments and recesses fall on a common centre line as they revolve, the welding taking place at this position. The electrode, (sonotrode) (22), oscillates backwards and forwards as well as rotating, and apart from stripping the insulation from the wire (18), forms a solid electrical connection free from local hardening and thus hot spots, which cause armature breakdown.