Patent ID: 6455960
Filing Date: 2002-09-24
Classification: H02K

Abstract:
A direct drive external rotor DC motor for use in driving a belt carried by an external rotor, the motor comprising:a high thermal conductivity nonrotatable stator support shaft having a stator mounted thereon, the stator support shaft secured at either end thereof in a thermally conductive manner to a heat dissipating motor support structure; the external rotor including a cylindrical rotor housing surrounding the stator and mounted for rotation on the stator shaft, the cylindrical rotor housing acting as a drive roller to propel the belt carried by the external rotor cylindrical rotor housing; and the cylindrical rotor housing having internally secured thereto for rotation therewith an annular permanent magnetic structure that cooperates with a rotating magnetic field in the stator to generate a drive torque in the external rotor/permanent magnetic structure to thereby propel the belt; wherein thermal energy defined by the i2R losses in stator coils and the magnetic core loss of the stator is thermally conducted via the stator support shaft into the motor support structure to be dissipated therefrom thereby enhancing the DC motor operating efficiency.