Method of making rotor coil of coreless motor

DETAILED DESCRIPTION What is claimed is: 1.
In a method of making a cylindrical rotor coil for use in a coreless electric motor, wherein a substantially cylindrical coil is formed from an insulation coated conductive wire by diagonally folding back the wire at respective axial and edge portions of a cylindrical shape to sequentially form respective inner and outer coil layer turns running diagonally from one end edge to the other while intersecting at an angle the other layer turn, the improvement wherein said coil is compacted by the steps of: positioning within said coil is mandrel having an outer diameter smaller than an inner diameter of said coil, and applying pressure to said coil in radial inward directions against an outer periphery of said coil while maintaining flat rigid die surfaces in abutting relationship with both axial ends of said coil, to generally flatten the portions of said wire defining inner and outer peripheries of said coil and to radially inwardly compress together the turns of said coil against said mandrel for reducing the radial thickness of said coil and reducing the inner and outer diameters of said coil.
2.
A method according to claim 1 including the step of changing the rotational position of said compressed coil relative to the radial inward pressure and repeating said applying step.




Description:
This invention relates to a method of making a cylindrical rotor coil of a coreless motor and, more particularly, to a method of making an improved rotor coil of the type which is cylindrically wound and rotatably disposed in a cylindrical magnetic gap of a stator arrangement of the coreless motor.
In order to achieve highly efficient performance characteristics of the coreless motor, it is necessary to make the magnetic gap between an axial magnetic pole member on one hand and a yoke encircling the member to form the stator arrangement therewith on the other hand to be as small as possible.
Thus, the magnetic flux density, which is determinative of the electromotive force for causing the rotor coil to be rotated in the gap, will be as high as possible