Conventionally, a rotor is known to have a core body including a through-hole. In a rotor disclosed in JP-2008-182862A, a core body includes through-holes passing through the core body in a thickness direction, and the through-holes are arranged in a circumferential direction of the core body. Thus, the rotor may be lighter in weight and may have less inertia.
Further, the rotor has magnets and a magnet cover. The magnets are disposed on an outer wall of the core body to be arranged in the circumferential direction. The magnet cover has a tubular shape and is positioned radially-outward of the core body such that an inner wall of the magnet cover contacts to the magnets. An end of the magnet cover is sealed by a magnet holder. Thus, when the magnets are broken while the rotor rotates, pieces of the magnets are restricted from coming out through the end of the magnet cover.
However, when the magnet holder seals the end of the magnet cover, the through-hole is also sealed by the magnet holder. In this case, when the rotor rotates, the core body produces heat by eddy-current loss, and the heat may be retained in the through-holes. Therefore, temperature of the core body and temperature of the magnets are increased, and the magnets may be demagnetized by the heat. Accordingly, output power of a rotating electric machine may be decreased.
USPTO Backgrounds
USPTO Backgrounds