Abstract: An armature for a motor has a core, which comprises a plurality of core sheets stacked together in an axial direction. Each sheet has a plurality of teeth having an extended protrusion which covers an armature winding fitted in slots. The extended protrusion may be a pair of bendable long protrusion pieces on each tooth of one sheet, and a pair of bendable short protrusion pieces on each tooth of another sheet stacked adjacently to the one sheet. Alternatively, the extended protrusion may be a pair of long protrusion piece and short protrusion piece on each tooth. The protrusion pieces are bent to cover the armature winding after winding operation, leaving only a narrow slit between the two extended protrusions. The slit is discontinuous in an axial direction of the core. Thus, the armature winding is restricted from slipping out from the slots, and cogging in torque of the motor is reduced.