Patent ID: 7550883

Claim:
A spindle motor for holding and rotating a data storage disk, comprising: a stator including a plurality of teeth disposed in a radial pattern about a central axis extending in an axial direction of the motor, and coils disposed around the teeth, respectively; and a rotor supported in the motor so as to be rotatable about the central axis, wherein the rotor includes a rotor magnet having an end surface, and a peripheral surface along which poles of the magnet lie, the poles facing and spaced from the plurality of teeth in a radial direction of the motor such that a radial first clearance exists between the peripheral surface of the rotor magnet and the teeth, a disk supporting portion having a support surface and dedicated and configured to support the data storage disk, and a flange of ferromagnetic material juxtaposed with the rotor magnet in the axial direction of the motor, the support surface of the disk mounting portion and the flange being offset from one another in the axial direction of the motor, and the flange having a shield surface that faces and is spaced from the end surface of the rotor magnet one way in the axial direction of the motor such that an axial second clearance exists between the end surface of the rotor magnet and the shield surface of the flange, and a rim projecting from the shield surface back the other way in the axial direction of the motor such that the rim and the support surface of the disk supporting portion of the rotor face in opposite directions, the rim extending along an annulus offset from the peripheral surface of the rotor magnet in the radial direction of the motor, wherein the rim is located over the teeth of the stator in the axial direction such that no portion of flange projects between the peripheral surface of the rotor magnet and the teeth.