GB1193014A - Aluminum Armature and Method for Making Same - Google Patents

Abstract

1,193,014. Making armatures for dynamo-electric machines; welding by pressure. PHOTOCIRCUITS CORP. 29 March, 1968 [3 April, 1967], No. 15361/68. Headings B3A and B3R. [Also in Division H2] An armature comprises a plurality of arrays of stamped-out aluminium conductors interconnected so that successive conductors lie in different arrays, adjacent arrays having insulation between them and the conductors of one array being partially provided with copper surfaces to form a commutator. Fig. 2 shows the construction of a disc armature wherein aluminium sheets 20, 21 are stamped to form conductors 11 with inner and outer tabs 10, 13. The sheets are then placed face to face on either side of an insulating disc 22 and the tabs joined to form complete winding turns interconnected as an 8-pole wave winding, the unwanted material of the sheets being removed at suitable times during the operation. The conductors formed from sheet 21 carry the copper surfaces 11<SP>1</SP>. Fig. 6 shows the armature forming part of a motor comprising a two-part casing 40 each part carrying respectively a ring of permanent magnet polepieces 41 and an iron ring 43 located adjacent opposite faces of the armature. Brushes 54 engage the copper surfaces 11. The armature may have more than two superimposed arrays of conductors, the tabs thereof being interconnected to form a winding with multi-turn coils (Figs. 7-10, not shown). Several methods of producing the armature are described. For example, one of the aluminium sheets may have a copper surface initially formed thereon, e.g. by plating, which is subsequently etched away to form the commutator using a masking process. Alternatively copper may be applied where required to a masked blank or stamped or assembled array of conductors by plating. In another method a copper foil track and an aluminium blank are first sandblasted and the foil is then bonded to the aluminium using platens, heated, for example, to 600‹ C. and applied with a pressure of about 1000 p.s.i.