A stator and a manufacturing method thereof is enabled to easily determine the quality of welding produced between conductors. The stator includes a stator core and a stator winding installed in the stator core. The stator winding is configured by including multiple flat conductor segments in which conductors 34 are coated with insulating films 35, respectively. At a leading end of each of the conductor segment, an exposed portion 33 is formed in which the conductor is exposed. At a coil end section of the stator winding, a pair of exposed portions of different conductor segments are joined together by laser welding. A collective conductor width in a joining direction in which exposed portions join with each other is smaller at a laser irradiation incidence side, which is a side of the exposed portions receiving laser irradiation than that at a side opposite to the laser irradiation incidence side.

A method is presented for producing an arrangement of coil elements for a plug-in coil of an electric machine. The method includes providing a workpiece carrier and producing an arrangement of rod-shaped coil elements for a plug-in coil of an electric machine on the workpiece carrier, wherein the following is respectively provided for the rod-shaped coil elements: accommodating and holding the coil elements by means of a displacement device; supplying the coil element onto the workpiece carrier by means of the displacement device into an assigned proximal position on the workpiece carrier, wherein the coil elements are hereby displaced form a distal position into the assigned proximal position with respect to the workpiece carrier; and transferring the coil elements in the proximal position on the workpiece carrier from the displacement device by a gripping device, which is formed on the workpiece carrier.

First-fourth slots may be provided in an inner circumferential surface of a stator core. A coil may include first-third segments conductor. Each of the conductors may include a U-shape. The first segment conductor may be inserted in the first slot and the second slot in a state where a coupling portion of the first segment conductor is located at a position facing a first end surface. The second segment conductor may be inserted in the second slot and the third slot in a state where a coupling portion of the second segment conductor may be located at a position facing a second end surface. The third segment conductor may be inserted in the third slot and the fourth slot in a state where a coupling portion of the third segment conductor may be located at a position facing the first end surface.

A stator may include a stator core and a coil. The stator core may include: a first portion; a second portion; and a first intermediate portion interposed between the first portion and the second portion in the axial direction. A first segment conductor and a second segment conductor may overly each other in a circumferential direction of the stator core hr a slot within an area of the first intermediate portion. A first side surface may include a first protrusion provided by the first intermediate portion protruding with respect to the first portion and the second portion. The first segment conductor and the second segment conductor may be held between the first protrusion and a second side surface such that the first, segment conductor and the second segment conductor are connected with each other.

An aligning apparatus, which is provided for aligning coil segments to form an aligned coil, includes a cylindrical jig and a hook jig. The cylindrical jig has an outer cylinder to surround a radially outer periphery of the aligned coil and an inner cylinder to be surrounded by a radially inner periphery of the aligned coil. The hook jig has hooks arranged in a radial fashion and is rotatable relative to the cylindrical jig in a radial direction. The cylindrical jig further has an inner entrance provided in the inner cylinder, an outer entrance provided in the outer cylinder, and at least one of an inner guide wall extending from a front opening edge of the inner entrance radially inward and backward in the rotational direction and an outer guide wall extending from a front opening edge of the outer entrance radially outward and backward in the rotational direction.

A coil manufacturing device for manufacturing a coil by rotating a winding core and winding a wire around the rotating winding core, the coil manufacturing device includes a recess formed in the winding core, the recess being configured to suspend the wire wound around the winding core in the recess; and a wire bundling device configured to bundle the wire suspended in the recess.

A coil segment forming apparatus includes a second bending section for bending a first bent body consisting of a pair of slot insertion portions that are substantially parallel to each other and a linking portion for connecting the pair of slot insertion portions formed in the same plane. The bending of the first bent body is carried out in a plane perpendicular to the aforementioned same plane. The second bending section has a plurality of pairs of press jigs arranged to oppose to each other in directions intersecting with the aforementioned same plane for pinching and pressing the linking portion, and a plurality of drive mechanisms for moving respectively the plurality of pairs of press jigs in directions intersecting with the aforementioned same plane based on moving amounts respectively set depending on forming conditions of the coil segment to be formed.

A method for producing an electric motor having a coil includes providing a coil core where the coil core has a slot which extends in a longitudinal direction of the coil core. The method further includes introducing a slot insulation into the slot such that the slot insulation projects beyond the coil core in the longitudinal direction and forms a projection, introducing a conductor material layer by layer into the slot, and using a first layer of the conductor material to retain the slot insulation in a region of the projection during an introduction of a second layer of the conductor material into the slot.

An apparatus for manufacturing a stator includes a placement table, a supporting member and a resistance heating device. The placement table is configured to have a stator core, which has coil segments and insulators inserted in slots thereof, placed thereon. The stator core is formed of steel sheets that are laminated in an axial direction of the stator core. The coil segments together form a stator coil. The insulators are formed of a material that is foamable upon being heated. The supporting member is configured to support, in the axial direction of the stator core, distal end portions of teeth of the stator core so as to prevent gaps from being formed between the steel sheets forming the stator core. The resistance heating device is configured to heat, through energization of the stator coil, the insulators along with the stator coil and thereby cause the insulators to foam.

A coil insertion apparatus includes a coil diameter expander that expands a diameter of a coil assembly in a wound state from inside a stator core to insert the coil assembly into slots of the stator core, the coil diameter expander including a coil end pressing part that presses coil ends of the coil assembly from inside toward outside to expand the diameter, and a coil straight part pressing part that presses coil straight parts of the coil assembly to be inserted into the slots from inside toward outside to expand the diameter.