Patent GB-943822-A (GB)
Title: Metal laminated structures for electro-magnetic devices and methods of making such structures
IPC: H02K1/26
Filed: 1962-06-21
Abstract: 943.822. Seaming; making dynamo-electric machines; making punches and dies; jointing by stamping; riveting; shearing and punching. GENERAL MOTORS CORPORATION. June 21, 1962 [July 19, 1961 (2)], No. 23921/62. Headings B3A, B3J, B3Q, B3U and B3W. [Also in Division H2] A of method making metal laminated structures, such as dynamo-electric machine stators and rotors, comprises cutting a series of pairs of slits in each lamination, superimposing the laminations with their slits in alignment and successively forming each topmost lamination with a series of projections and complementary indentations incorporating the slits so as to fix the laminations one to another. A rotor lamination 26 (Fig. 1) is pierced and cut from a strip in two stages V, W, the second stage also forming the first stage of a four stage process W, X, Y, Z for forming a stator lamination 32. This process is carried out on a conventional multi-stage press tool (Figs. 22, 23) except that there is provision at the final stage for a rotatable die portion to enable double skewed and helical winding slots to be formed in the stators if required. Referring to Fig. 5 the last operation also comprises forming the corresponding indentations 39 and projections 40 in each successive topmost lamination and force fit assembling the projection in the indentation of the lamination immediately below it. Figs. 10, 11, 17, 19 and 28 (not shown) show various alternative forms and positions of the projections. Where the projections are formed in conjunction solely with a pair of slits which do not extend to an edge of the lamination, the shaped portions of the projections (e.g. 42 in Fig. 5) are stretched and consequently have a reduced thickness. In each embodiment, a special lowermost lamination may be provided which has a series of holes punched in it to accommodate the projections of the next lamination, thus enabling completed assemblies to be stacked on one another without inadvertent interlocking therebetween. Fig. 19 shows a laminated structure in which the slits incorporated in the projections extended to the outer edge of each lamination; the structure in this embodiment is completed by welding the ends of the projections 105 as at 106, and grinding off the projection portions 112 which extend beyond the top face of the structure. The press tool (Figs. 22 and 23) is a six station hydraulically operated tool incorporating a pressure pad, and a rotating die at its sixth station. At the first station a central punch 222 forms a rotor shaft hole and a group of punches 723 form further holes. At stations 2 and 3 further holes may be pierced, and station 4, which is provided with spring loaded ejectors 231, the interlocking projections are formed. A punch 238 at the 5th station has a centralising pin for coaxially locating the hole pierced by punch 222 at the first station, and is used for enlarging this hole as required. The 6th Station includes a rotating die 241 which is rotated by a small amount between each stamping operation by means of a worm-wheel 246 and worm 249 mounted on a shaft 250 driven intermittently through a cam actuated one way clutch (see also Figs. 24 and 25, not shown).