| 摘要 |
PURPOSE:To increase the torque constant by providing a rotor plate which covers the outside surface of a rotor made up of an annular magnet and by constituting a boss inside the magnet and magnetizing desired number of poles to the outside circumferential surface and at the same time by forming a gear. CONSTITUTION:A plane-shaped rotor R is faced to a stator yoke 4a composed of a stator plate 4a and a stator coil 5. An axis 6 is rotatably supported with a bearing 7 and fixed to a boss 3 of the rotor R. A plane-shaped permanent magnet 1 constituting the rotor R is magnetized to the predetermined multiple poles. A rotor plate 2 is provided, which is made up of a magnetic material to cover the lower surface and outside circumferential surface of a permanent magnet 1 with the inside circumferential surface fixed to the boss 3 and with multiple poles of magnetized FG magnet 13 fixed to the outside circumferential surface, and rotated integrally with the rotor R. Close to the FG magnet 13 an element 11 to detect the magnetic change is provided. On the outside circumference of the FG magnet 13 a gear 14 made of the same material is provided. Thus, the high torque can be outputted even in low rotation. |
