GB1281314A - Method of manufacturing squirrel cage rotor winding assemblies - Google Patents

Abstract

1281314 Making squirrel cage rotors; forging; extruding GENERAL MOTORS CORP 19 April 1971 [7 April 1970 (2)] 25237/71 Headings B3A B3H and B3P A metal slug 28 e.g. of aluminium or copper is extruded in a press 34 through slots 16 in a rotor core 12 to form the rotor bars (20) of a squirrel cage winding assembly (18) of a rotor (10), Fig. 1 (not shown). The core lamination stack is pressed into a mounting block 38, which is assembled with a die plate 36, guide block 42 and mandrel 40. The extrusion chamber 54 so formed has a radial width greater than or equal to the radial depth of the slots 16. A piston 62 is placed on an aluminium slug and a ram 60 is lowered on to the piston. The press 34 is heated to 1000-1150‹ F., the temperature being such that the temperature rise due to extrusion does not cause melting of the aluminium. The extruded aluminium passes into an annular cavity 64 to form an end ring (22) and sufficient material is left in the chamber 54 to form an end ring (24), Fig. 1. The end rings may be formed to the required shape in the press 34 or other dies may be used to press them to their final shape. In an alternative form of press, Figs. 12-14 (not shown) slugs (232), (234) are positioned on either side of the core laminations and extruded into the core slots (216). The extruded material fills the slots and a metallurgical bond (298) of the material of the slugs is formed at the slot centres, Fig. 14.