| 摘要 |
PURPOSE:To obtain a braking mechanism which has low power and generates less heat by employing a rotary type for a solenoid which brakes the rotation of a recording medium and rotating it by changing directions of voltage impression to a driven coil, and holding the state in the impression after the voltage impression is released. CONSTITUTION:When electricity is fed as shown in a figure, an arm 21 presses a brake pad 22 against the rotor part 23 of a main spindle motor by the attracting force between the permanent magnet of a rotor 26 and the produced magnetic pole of a core 27 to brake the rotation. When the main spindle motor is driven, the voltage is impressed in the opposite direction to obtain the magnetic pole at the core 27 as shown in a figure, and the arm moves as shown by an arrow 28 by being repulsed by the rotor 26 to stop where it strikes a stopper 29. Even if the voltage impression is stopped in said state, the attracting force is generated between the permanent magnet of the rotor 26 and the core, so the arm is held at the position opposite to that in a figure. |
