Patent ID: 8084899

Claim:
A driving apparatus comprising: a first cylindrically shaped magnet whose outer circumferential surface is alternately magnetized as different polarities in the circumferential direction; a second cylindrically shaped magnet whose outer circumferential surface is alternately magnetized as different polarities in the circumferential direction; a rotor integrally formed with magnetic pole portions made of a soft magnetic material, the rotor having a cylindrical shape, and a plurality of notched portions formed on circumferential surfaces of the rotor, the magnetic pole portions being comprised on portions between the plurality of notched portions, the magnetic pole portions of the rotor being opposite to outer circumferential surfaces of the first cylindrically shaped magnet and the second cylindrically shaped magnet; wherein the first and the second cylindrically shaped magnets are fixed to a stator; a first coil fixed to the stator to magnetically excite a portion opposite to the first cylindrically shaped magnet at the magnetic pole portions of the rotor; and a second coil fixed to the stator to magnetically excite a portion opposite to the second cylindrically shaped magnet at the magnetic pole portions of the rotor, wherein the stator has cylindrical shape, a first magnetic-flux transfer portion and a second magnetic-flux transfer portion are serially provided on the stator along an axis of the stator, the first cylindrically shaped magnet and the first coil are fixed between one end of the stator and the first magnetic-flux transfer portion, and the second cylindrically shaped magnet and the second coil are fixed between another end of the stator and the second magnetic-flux transfer portion.