Stator assembling method

A method for mounting a plurality of concentrically wound coils to an annular stator core, the method comprising:

• separately providing the stator core that includes an inner diameter side and an outer diameter side, and a coil assembly in which the plurality of concentrically wound coils are disposed annularly, wherein:
• the coil assembly further comprising forming each of the concentrically wound coils by winding a plurality of turns of a conductive wire, the each of the concentrically wound coils having planned slot accommodation portions and planned coil end portions,
• the stator core further comprising slots formed between adjacent teeth extending from a back yoke to a radially inner side, a spacing between the slots being widened toward a radially outer side, and
• the each of the plurality of the concentrically wound coils that is formed has vertexes oriented outward in an axial direction in the planned coil end portions, and a distance in the axial direction between the vertexes of the planned coil end portions on both sides in the axial direction of each of the plurality of concentrically wound coils is gradually reduced toward the conductive wire to be mounted on the inner diameter side of the stator core from the conductive wire to be mounted on the outer diameter side of the stator core;
• and
• mounting the plurality of the concentrically wound coils onto the stator core by pushing the plurality of the concentrically wound coils included in the coil assembly disposed in a space on the inner diameter side of the stator core to the outer diameter side and inserting the plurality of the concentrically wound coils into the slots of the stator core, wherein, after the plurality of concentrically wound coils are mounted to the stator core, the distance in the axial direction is identical in the part from the conductive wires mounted to the inner diameter side of the stator core to the conductive wires mounted to the outer diameter side of the stator core.