Concentrated winding stator coil for an electric rotary machine

A concentrated winding stator coil for an electric rotary machine comprising:

• plural tooth coils respectively wound around teeth of a stator core, each tooth coil comprising:
• a first layer coil consisting of plural turns arranged by successively winding an insulation coated coil conductor around a tooth of said stator core in a direction advancing from a proximal end portion of the tooth to a distal end portion of said tooth to cooperatively form a same layer, the first layer coil having a winding start end disposed at the proximal end portion of said tooth;
• a second layer coil consisting of plural turns, including a start turn continuously returned from a final turn of said first layer coil, arranged by successively winding the insulation coated coil conductor on and around said first layer coil in a direction advancing from the distal end portion to the proximal end portion of said tooth to cooperatively form a same layer, the second layer coil having a winding terminal end disposed at the proximal end portion of said tooth;
• a first lead wire portion extending from said winding start end of the first layer coil toward a core back of said stator core;
• and
• a second lead wire portion extending from said winding terminal end of the second layer coil toward the core back of said stator core,
• wherein said stator coil further comprises:
• a phase winding including plural inter-coil bus bars serving as inter-coil connection wires, plural terminal bus bars serving as unit terminal connection wires, and a plurality of neutral bus bars,
• said plural inter-coil bus bars serially connect the tooth coils to form a plurality of serial coil units for each of a plurality of phases such that each of said plural inter-coil bus bars connects the first lead wire portion of one tooth coil and the second lead wire portion of another tooth coil and such that a set of serial coil units includes one serial coil unit of each phase to form a plurality of sets of serial coil units.
• each of said neutral bus bars connects first ends of the serial coil units of the same set with one another to connect the serial coil units with one another for each set,
• each of said plural terminal bus bars extends from second ends of said serial coil units of the same phase to connect said serial coil units in parallel with each other for each phase,
• said inter-coil bus bars and said terminal bus bars are disposed adjacently to an end face of said core back so as to form a plurality of layers along an axial direction of the stator core in a bus bar accommodation space, and
• the neutral bus bars are disposed together with the inter-coil bus bars in the bus bar accommodation space to form the same layer as one of those of the inter-coil bus bars such that the neutral bus bars are located so as not to interfere with the inter-coil bus bars.