Patent ID: 7116031
Filing Date: 2006-10-03
Classification: D06F,H02K,Y10T

Abstract:
1. A helical core, which has a multi-layer structure configured by helically winding to stack a steel plate core from a bottom layer to a top layer, the helical core comprising the steel plate core blanked in two rows from an electrical steel sheet to form a pair of bases confronting each other in a width direction with teeth protruding from each of the bases to alternately cross each other, wherein in order to prevent an unwinding of the steel plate core in a direction reverse to a rotation of the steel plate core and a loosening between the stacked layers of the steel plate core of the helically winding, an engaging protrusion is provided in each upper or lower surface of the teeth of the steel plate core and an engaging recess is provided in each lower or upper surface of the teeth of the steel plate core to correspond to the engaging protrusion, and wherein a recess is provided in the base to reduce the stress in winding the steel plate core, both corners of an end of each of the teeth being chamfered straight or round to form a ‘C’ shape to reduce vibration and noise generated by cogging torque on driving a motor, and ejector concaves are provided on the teeth of the steel plate core to facilitate a separation of the steel plate core.