Patent ID: 7227290

Claim:
A rotor core, comprising: a ring body; and a plurality of teeth extending radially outward from an outer circumference of the ring body, wherein each tooth includes: a coil winding portion about which a coil is wound, wherein the coil winding portion includes a proximal section and a distal section, the proximal section being coupled to the ring body, and the distal section being located radially outward of the proximal section; and a magnetism converging portion provided at the distal section of the coil winding portion, wherein the measurement of each coil winding portion with respect to the axial direction of the rotor core gradually increases from the distal section to the proximal section, and the measurement of each coil winding portion with respect to the circumferential direction of the rotor core gradually decreases from the distal section to the proximal section, wherein the rotor core includes a plurality of assembled core members, wherein each core member has part of the teeth the number of which obtained by dividing the total number of the teeth of the rotor core by the number of the core members, and wherein the teeth of each core member are spaced at equal angular intervals, wherein a cross-sectional area of the coil winding portion of each tooth perpendicular to the extending direction of the coil winding portion is constant from the distal section to the proximal section, and wherein four sides of the coil winding portion of each tooth that extend in the extending direction of the coil winding portion are curved inward.