Coil unit of coreless armature and method of manufacturing the same

Claim 1

A coil unit of a coreless armature for use with means creating a magnetic field, said coil unit comprising at least a pair of inner and outer coil wire layers, said layers being formed by mutually separate inner and outer cylindrical coil elements, respectively, each said element comprising a plurality of coil wire sections of a conductor having an insulation coating and mutually parallely arranged along the periphery of cylindrical shape of said cylindrical element while running from one of both axial end edges of said cylindrical shape to the other relatively in intersecting relationship to said wire sections in the other element, said separate inner and outer coil elements being assembled closely coaxially so as to opposite, in radial direction of the cylindrical shape, each end of said wire sections in one of the elements to each end of the wire sections in the other element at each of said axial ends, said wire sections of each of said elements being twisted into a helical orientation, with the twisting of the wire sections of said element being performed in a direction opposite that of the other element to establish said intersecting relationship, and means for electrically connecting between said radially opposed ends of the wire sections of the respective elements for forming an electrically closed loop of coil in which the wire sections intersecting diagonally the magnetic field, said electric connecting means comprising a fused nugget of said conductor of said wire sections exposed at said axial end edges.