Abstract: A rotating drum in which, when the rotating drum is rotated at high speed, there is no offset between divisional drum parts, there is little imbalance, and a moment of inertia for rotation is small. A drum main body is divided into four drum parts whose cross-sectional configurations orthogonal to an axis are fan-shaped. Female projecting portions and male projecting portions are formed at a pitch dimension having a predetermined fit-together tolerance. Thus, the drum parts can be assembled together with a certain amount of leeway at a time of assembly. After the four drum parts have been assembled together, wires are press-fit in from an end surface side of the drum main body so as to tightly fasten the drum parts. Because the assembled drum main body defines configurations of the drum parts to have point symmetry, imbalance can be made small.

Abstract: A rotating drum in which, when the rotating drum is rotated at high speed, there is no offset between divisional drum parts, there is little imbalance, and a moment of inertia for rotation is small. A drum main body is divided into four drum parts whose cross-sectional configurations orthogonal to an axis are fan-shaped. Female projecting portions and male projecting portions are formed at a pitch dimension having a predetermined fit-together tolerance. Thus, the drum parts can be assembled together with a certain amount of leeway at a time of assembly. After the four drum parts have been assembled together, wires are press-fit in from an end surface side of the drum main body so as to tightly fasten the drum parts. Because the assembled drum main body defines configurations of the drum parts to have point symmetry, imbalance can be made small.