Motor manufacturing method

A motor manufacturing method in which a motor having a ring-shaped motor core provided with a plurality of slots on an inner peripheral surface, and coil groups of plural phases are provided, the coil group in each of the phases being structured from a plurality of unipolar coils corresponding to one pole, each of the unipolar coils being inserted and disposed in the motor core by being passed through two of the slots so as to straddle the slots, and the unipolar coils belonging to the different phases of coil groups being overlapped with each other in portions of the respective coil end portions when in a state of being attached to the motor core, characterized by comprising:

• a coil formation step of forming the unipolar coil, having coil inserting portions at two positions inserted to the slots and having the coil end portions at two positions disposed in an outer portion of the motor core so as to connect the coil inserting portions, into a shape such that a size in a height direction parallel to the coil inserting portion changes so as to be larger in an inner peripheral side corresponding to a diametrical direction of the motor core along a direction of a winding axis center than in an outer peripheral side, by winding a wire a plurality of times;
• and
• a coil insertion step of disposing the unipolar coil in such a manner that the two coil inserting portions in the unipolar coil respectively face toward inner peripheral opening portions of the slots and are substantially parallel to an axial direction of the motor core, and inserting the coil inserting portions of the unipolar coil into the slots by moving the unipolar coil toward the motor core substantially linearly while holding the motor core so that protrusion dimensions at both ends protruding from both end surface positions in the axial direction of the motor core are maintained substantially the same.