Abstract
This paper reports a high-density coil winding technology that enables to fabricate high efficient and small motors. When a square wire is wound in contact, the density of the coil in the stator core slots can be higher than that when a round wire is wound like piling straw bags. However when the square wire is wound only by the motions of the nozzle and the rotation axis, the alignment of the wire is crumbled due to the gap caused by the slip of the wire. Thus a system that can wind square wire without gaps and crumbling was proposed. The system has guides that restrict the positions of the wire rotating with the coil. An experimental device of this system was driven at 2.5 rotations per second, and the guides were controlled in synchronization with the rotation axis. As a result, concentrated wound plural layer coils were fabricated without gaps by winding square wires in contact. The slot-fill rate of the experimental coil of a square wire is 80%, while the slot-fill rate of the conventional coil of a round wire is 68%. This system can be applied to the motors whose stators are constructed of divided cores, and it makes these motors small and highly efficient.
