| 摘要 |
PURPOSE:To prevent magnets from being broken and scattered by such an arrangement wherein magnets to be provided at the inner circumference of a flywheel are enveloped by cylindrical portions and rings of the flywheel and filler material. CONSTITUTION:A flywheel 2 is composed of a cup-like magnetic substance having a boss 1 at its revolving center, and magnets 3 are provided at the inner circumference of the cylindrical portion of the flywheel 2 and cylindrical rings 4 made of thin metal plate are provided at the inner circumference of those magnets so that they support the magnets 3 and filler material 5 is filled up between both ends of the rings 4 and the flywheel 2 so that it envelops both edges of the magnets 3. Since the circumference of the magnets 3 is encircled by the cylindrical portion 2a of the flywheel 2, rings 4 and filler material 5, the magnets are no longer scattered around even if they are accidentaly broken. |
