GB811183A - Improvements in or relating to laminated stators for electric motors - Google Patents

Abstract

811,183. Making stator cores; welding by pressure; coiling. WESTINGHOUSE ELECTRIC INTERNATIONAL CO. Sept. 6, 1956 [Sept. 12, 1955], No. 27321/56. Classes 83 (2) and 83 (4). [Also in Group XXXV] In a stator coil for an electric motor comprising toothed laminations held together in a compressed unit by a plurality of welds extending transversely across the peripheries of the laminations each lamination is formed with a tapered portion the thickness of which decreases from the roots of the teeth towards the outer periphery of the lamination and each weld is effected by pressure welding with a material which softens during the welding, operation and enters the spaces between the tapered portions of the laminations. A strip STR, Fig. 1, of oriented silicon steel is stamped with slots 21 and slits 22 to form two toothed strips ST. A strip ST is passed between adjustable tapered rolls to taper the metal from the roots of the teeth all or part of the way to the edge of the strip to cause the strip to form itself into an edge wound helix. As shown in Fig. 2 a narrow rib 37 may be formed on the edge of the strip. The helix is compressed by four spaced clamps 45, Fig. 8, while arranged on a mandrel having keys to enter the spaces between the teeth, the mandrel' being then removed. A steel rod 61 is held axially along the helix by an electrode E1, the other electrode E2 being in contact with the laminations and current is passed to fuse the rod into the periphery of the helix. When laminations as in Fig. 2 are used the rib 37 upsets to allow the penetration of the weld metal. Eight such welds may be made. In a modification a keyed mandrel is left within the helix while the helix is compressed by pneumatic or hydraulic means and each electrode welds a rod to the helix.