| 摘要 |
PURPOSE:To increase the driving torque of rotor by arranging a motor driving apparatus of specific structure in an arcuate shape within a camera lens-barrel. CONSTITUTION:A motor driving apparatus to be used for driving a focus ring of camera lens-barrel is equipped with a motor unit base 1, a first fixed magnetic pole member 2 having a stator 2a, a first stator winding 3, a first magnetic core member 4 having a stator 4a, a rotor 6 composed of a permanent magnet with two poles N, S and its shaft 7a, a bearing 8 and a gear 9 at the other end of the shaft 7a, and further provided with a second fixed magnetic pole member 10 having a stator 10a, a second stator winding 11, a second magnetic core member 12 having a stator 12a and others to transmit the rotation of the rotor 6 to a gear 18 via gears 9, 13, 15, 17 and also to a focusing portion. Thus, a closed loop formed by a line joining the stator 4a, fixed magnetic pole member 2, stator 2a, rotor 6 and stator 4a decreases loss of magnetic energy and increases torque. |
