| 摘要 |
PURPOSE:To obtain a stable screen with a simple constitution without developing a tortional resonance in the rotational direction by fixing the rotational part of a rotary drum device in one direction of a shaft. CONSTITUTION:A motor startor 10 is fitted to the lower drum 9 of the rotary drum device for a VTR, while a rotar magnet 12 is fitted to an upper drum 4. A flange 3 is integrally fitted to the rotary shaft 1, and a video head 5 is arranged on the flange 3. The upper drum 4 is regarded as a 1st rotational part, and a 2nd rotational part by the lower drum 9 where the motor startor 10 is arranged is provided, facing the magnet 12 in the 1st rotational part. The 2nd rotational part is fitted to the rotary shaft 1 through bearings 6 and 7. Such a constitution is adopted that no rotational member is fitted on the lower part of the rotary shaft 1, and the moment of inertia of the drum device is set to zero. A resonance frequency is set infinite to make the size of the entire drum thin, thereby obtaining a stable image.
|
