| 摘要 |
PURPOSE:To generate a video position detection signal having sufficient magnitude by forming the magnetic field of the pole at the position corresponding to the stational position of a video head to a strong magnetic field at least equivalent to or higher than the magnetic field of other pole. CONSTITUTION:A flat groove 70 is formed on the bottom surface of a rotor yoke 6. The angle of the groove 7 is formed to an angle which is formed of a pole 1p and a half of the adjacent pole. With this structure, a magnetic circuit permeance between a magnet 1 and the rotor yoke 6 becomes maximum at the position of the pole 1p, and can generate the strongest surface magnetic field as compared with the other pole. The pole 1p is disposed at the position corresponding to the stationary position of a video head. |
