Patent ID: 7312543
Filing Date: 2007-12-25
Classification: H02K

Abstract:
1. A driving device comprising: a magnet having an annular shape, retained so as to be rotated in a plane about an axis passing through substantially the center of the annulus, with at least one of the surfaces of the magnet being substantially perpendicular to the axis of rotation and having adjacent areas magnetized to different polarities; a concentric coil disposed outside and overlapping said magnet in the plane of rotation; a yoke including a rotating yoke including a second magnetic-pole portion fixed to the opposite surface of said magnet, and rotatable integrally with said magnet, and also magnetized by said coil; wherein the cylindrical portion of said yoke and the outermost diameter portion of said rotating yoke are configured to face with each other across a second gap in the radial direction to form a stable magnetic circuit.