Patent ID: 8424407

Claim:
A core metal, comprising: a shaft through-hole provided in a central portion of a flat circular metal plate so as to allow a shaft to be inserted in the shaft through-hole; and a resin locking portion provided in an outer peripheral portion of the flat circular metal plate, wherein: the shaft through-hole has a prepared hole and a thicker periphery provided on an outer portion of the prepared hole; the thicker periphery is projected from at least one of a front surface and a back surface of the flat circular metal plate; the thicker periphery is increased in a thickness compared to an original thickness of the flat circular metal plate; and the resin locking portion includes at least one of a hole, a dent, a concavity/convexity, a gear, a notch, a cut-raised piece, a circular-arc groove, a ring groove, and other shapes, the resin locking portion is molded on the outer peripheral portion of the flat circular metal plate, and the resin locking portion is capable of locking and fixing a resin gear covering an outside of the resin locking portion and at least a portion of a side surface of the flat circular metal plate.