Patent ID: 7157823

Claim:
A brushless vibration motor comprising: an eccentric rotor having a rotor case, a magnet which has alternatively arranged plural magnetic poles and which is arranged on an inner peripheral surface of the rotor case, and a semi-cylindrical weight disposed on a portion of an outer peripheral surface of the rotor case at a radial outside of the magnet; a shaft for supporting the eccentric rotor; a stator for driving the rotor, through a radial gap between the eccentric rotor and the stator, the stator being cooperated with the magnet of the eccentric rotor through the radial gap, the stator being cored type of stator which includes a stator base, a substrate additionally mounted on an upper surface of the stator base, and armature coils, in which the stator base has a stepped shaft supporting portion for supporting the shaft, in which the armature coils are wound and arranged on at least two salient poles of a stator core that is mounted onto the shaft, and in which a plurality of sites for mounting the armature coils are provided on the substrate; a driving circuit member for applying electric current to the armature coils, which is disposed in a space provided within the housing, wherein the space is corresponding to at least one armature coil; a dummy core being risen from the stator base at an even angular pitch, which is arranged on an outer periphery of the stator base, wherein the angular pitch is corresponding to that of the salient poles arranged around the stator core; and a cover being attached at an edge to the stator base, which encloses the eccentric rotor and performs a protection of the eccentric rotor.