| 摘要 |
PURPOSE:To stably support a rotor, to simplify an assembling of a dustproof seal, and to reduce the number of components by providing an annular magnetized part at a position opposed to the end of a bearing cylinder and an axial direction at the inner face of the rotor, and providing magnetic fluid for the seal between the magnetized part and the end of the cylinder. CONSTITUTION:An annular magnetized part 32 is extended integrally with the upper part of a rotor magnet 31 to oppose to the end face of the end 22a of a bearing cylinder 22 and an axial direction, magnetic fluid 33 for dustproof seal is interposed between the part 32 and the end 22a, and a sealed part 34 is composed of the part 32, the end 22a and the fluid 33. Since the part 34 is provided at the end of the cylinder 22, the position of a bearing 23 is not restricted by the part 34, can be extended axially. Accordingly, a rotational shaft 28 and a rotor 27 can be stably supported. The construction can be simplified by the installation of the part 34 out of the cylinder 22, omission of a pole plate, an integration of the part 32 with the magnet 31, etc., and the number of components can be reduced. |
