| 摘要 |
PURPOSE:To prevent a magnetic field generated by the motor from exerting bad influences to a vertical magnetic head by covering an outer circumference of a motor with a shield member including a high magnetic permeability mag netic material. CONSTITUTION:A driving motor 1 is completely covered with a cylindrical shield case 5 composed of a 'Permalloy(R)', iron, etc., and the shield case 5 is fixed to a steady member of the motor 1 by the suitable means. At such a time, an output shaft 1a of the motor 1 is projected from a circular hole 5a installed at the center of the upper surface of the shield case 5, and to prevent the leaking of a magnetic flux, the clearance between the output shaft 1a and the circular hole 5a is small as much as possible. Thus, when the circumference of the motor 1 is covered with the shield case 5, the magnetic field generated from the motor 1 is interrupted by the shield case 5 and will not go out from the case. Consequently, even when the motor is used for a direct motor driving system, the reproducing output level at the time of reproduction will not be decreased. |
