Automation of reaction metallurgical joining for copper conductors

摘要

Copper conductor members or other copper-based workpieces are welded using a suitable copper alloy material that is reactive with the joining surfaces of the copper members. The reactive metal material may be applied as a thin metal foil strip between assembled facing joining surfaces. The members are pressed together against the reactive material and electrical resistance heated in forming the weld. Practices are adapted for forming many such welds in the pairs of facing ends of conductor bars or wires assembled, for example, in slots in a stator for a vehicle traction motor. Practices are disclosed for shaping and automated placement of suitably sized and shaped foils of reactive metal. Practices are also disclosed for use of a resistance welding tool in aligning and heating the many pairs of conductors to be welded.

主权项

1. A method of joining a plurality of pairs of U-shaped, adjacent copper conductor wires that are assembled into a stator core for an electric motor, the stator core having the shape of a hollow right cylinder with an axial length for enclosing a rotor for the electric motor, the ends of the U-shaped copper conductor wires being arranged as a plurality of aligned pairs, the paired ends of the assembled copper conductors all being located at one end of the stator core and occupying the annular area of one end of the stator core in spaced radial pairings, where the end of one member of each copper conductor pair presents a first joining surface area facing a like-shaped, like-oriented, second joining surface of the end of its paired copper conductor member, each of the paired joining ends of the copper current collectors extending outwardly beyond the axial length of the stator core and so being accessible for welding at the one end of the hollow right cylinder shape; the method of forming the solid state welds comprising:
a) inserting reactive metal between the joining surface areas of more than one pair of selected adjacent copper conductors; b) using opposing electrode tools to apply pressure to each of the copper conductor pairs to either simultaneously or sequentially bring the facing joining surface areas of each pair of copper conductors into engagement with the reactive metal between them; c) passing electric current through the engaged, conductor-reactive metal-conductor grouping to heat and melt the reactive metal for reaction with the copper conductor surfaces, to form reaction by-products; d) expelling the reaction by-products from the facing, contacting joining surface areas of each of the copper conductor pairs to form a solid-state weld; e) stopping passage of the electric current; then f) repositioning either the opposing electrode tools or the stator to align at least a different conductor pair with the opposing electrode tools and repeating at least steps b)-e) until all copper conductor pairs have been joined together by solid-state welds.