METHOD OF MAKING ROTOR COIL OF CORELESS MOTOR

摘要

A method of making cylindrical rotor coil for use in coreless motors is provided whereby the coil is of a reduced thickness with compressed coil turns enabling the stator magnetic gap distance to be reduced, thus enabling a higher flux density to be utilized highly efficiently in the gap. A radially inward force is applied to a cylindrically wound coil of an insulation coated wire so as to act against the outer periphery of the cylindrical coil, whereby respective turns of the wire are compressed together and flattened on their portions defining the respective peripheries. The force application is preferably repeated while varying the relative position of the cylindrical coil in its peripheral directions to the applied force. A mandrel is inserted into the coil before the coil is compressed. The outer diameter of the mandrel is less than the inner diameter of the coil so that the inner and outer diameters of the coil is compressed radially inwardly against the mandrel. The axial ends of the coil are engaged by flat surfaces during the radial compression, to flatten such axial ends.