Armature of electric motor

An armature of an electric motor, comprising:

• armature cores which are arranged in parallel with a constant distance;
• an insulating holder by which each of coils, which is wound around the armature cores, is insulated and maintained;
• a plurality of bus bars which are laminated and arranged at the outside of the armature cores, and are electrically connected to terminals of each of the coils which is wound around the armature cores;
• wherein
• the insulating holder is composed of a bobbin portion which functions as a winding frame of the coils, and bus bar supporting portions by which portions between each of the bus bars are insulated and supported, and
• the bus bar supporting portions include bus bar walls which intervene between each of the bus bars, and electrically separate each of the bus bars, and
• step portions are formed, in a lamination direction of the bus bars, at the bus bar walls, and
• gap portions are formed, between the bus bars and the bus bar walls, in a longitudinal direction of the bus bars and in a lamination direction of the cores, at the step portions, and
• an insulating cap, which complements the gap portions from the outside and maintains the bus bars, is included, in a state where the bus bars are installed to the bus bar walls.