| 摘要 |
PURPOSE:To make a titled device small-sized by providing a comb-tooth yoke on the inside circumference of a coil attached to a fixed cylinder of a lens barrel, supporting a cylindrical magnet so as to be rotatable by holding a minute interval on the inside of the yoke, and engaging a moving lens holding cylinder with a cam groove provided on the inside circumference of the magnet. CONSTITUTION:A fixed cylinder 3 of a lens barrel 1 holds lenses G1-G4 and G6, and also holds a stator of a step-motor. As for the stator, field yokes 8, 9 engaged like comb-teeth 16a, 17a to an outside cylinder yoke 5 are fitted, and field coils 6, 7 are provided in an space formed by the yokes 5 and 8, 9. A rotor consists of a cylindrical magnet 11, and the magnet 11 is supported by ball bearings 15a, 15b against an inside cylinder 3a of the fixed cylinder 3. A groove 11a for placing bearings 15a, 15b, etc. are provided on the inside circumferential surface of the magnet 11. Also, a cam groove 11b is provided on the inside circumference of the magnet 11, and the groove 11b is engaged with a guide roller 14 of a moving cylinder 13 and drives to focus a lens G5. In this way, the outside diameter of the lens barrel can be reduced, and a device having a good driving performance is obtained. |
