Friction stir welding of a solder coated strand coil to a solid coil

A manufacturing method of a rotor coil for a revolving armature having a rotor, wherein the rotor coil comprises a strand coil, composed of a plurality of element wires and that includes a part arranged in a core slot of the rotor, and a solid coil, the manufacturing method comprising the steps of:

• soldering a top surface and a bottom surface of an end of the strand coil with a solder material placed on the top surface and the bottom surface to integrate the element wires at the end of the strand coil into one unit and leave clearance gaps between the element wires;
• inserting a tool, from a direction crossing the element wires, into a butt joint where an end of the solid coil and the end of the strand coil where the surface is soldered are butted against each other, the butt joint running along a width direction of the solid coil;
• and
• performing friction stir welding along the butt joint with the tool which includes melting the solder material with heat generated by the friction stir welding, making the melted soldered material flow into the clearance gaps between the element wires through capillary phenomenon, and increasing an intensity of the welded joint.

A manufacturing method of a rotor coil for a revolving armature having a rotor, wherein the rotor coil, comprises a strand coil composed of a plurality of element wires and that includes a part arranged in a core slot of the rotor, and a solid coil, the manufacturing method comprising the steps of:

• soldering a top surface and a bottom surface of an end of the strand coil to integrate the element wires at the end of the strand coil into one unit and leave clearance gaps between the element wires;
• forming a butt joint by making an end of the solid coil and the soldered end of the strand coil butt against each other;
• and
• performing friction stir welding on the butt joint which includes melting the solder material with heat generated by the friction stir welding and making the melted soldered material flow into the clearance gaps between the element wires, thereby forming a joint portion that joins the solid coil and the strand coil.