| 摘要 |
PURPOSE:To start a two-phase brushless motor reliably with no fluctuation of rotation, by enabling radial displacement of a portion of pole of a rotor magnet when a rotor is stopped thereby shifting field distribution. CONSTITUTION:A rotor magnet 4 is constructed with fixed members 9, 10 and movable members 11, 12 and magnetized as shown on the drawing. When a rotor is stopped, the movable members 11, 12 are energized in the direction of axis by a tensile coil 13 and moved toward the center. Consequently, field distribution for steady rotation of the rotor magnet 4 is shifted to produce starting torque. During steady rotation, the movable sections 11, 12 are moved outward through centrifugal force while resisting against the force of the tensile spring 13 and brought into concentric state with the fixed members 9, 10 so as to rotate the rotor with small cogging torque and small rotary fluctuation. |
