Methods for making and using slot closure wedges at a coil injection

Abstract

Apparatus involves advancing wedge material stock and also substantially permanently forming the stock material to precise dimensional tolerances by squeezing and deforming the material with pinch rollers. Deforming of the material includes pinching the material and thereby reducing the thickness of the material at preselected locations, with the reduced thickness portions of the material establishing precise dimensional tolerances of wedges produced by the process. A wedge magazine comprises the lower tooling of a coil injection machine and forms, in effect, an extension of tool gaps that accommodate winding coils in a coil injection machine. The magazine receiving the wedges may be a short term storage magazine which in turn feeds the wedges to a wedge magazine that forms the lower tooling of a coil injection machine. The present invention is of primary use and benefit in multifunction machines that perform the multiple functions of: making wedges for stator cores, inserting coils of winding turns into stator cores, and placing the wedges in at least selected slots of a stator core. Pinch wheels or rollers are contoured and dimensioned so that wedge material being rolled therebetween will be reduced in thickness at accurately located regions and formed into a desired configuration. The forming of the wedge material by the wheels results in wedges having precisely controlled dimensional tolerances and dimensional stability, with the result that the wedges lie squarely in stator core slots (when the wedges are inserted into such slots), and 'wire over wedge' problems associated with skewed wedges in stator core slots are overcome.