Direct drive outer rotor brushless dc motor drive wheel

An autonomous mobile robot comprising a motor controller, a battery, and at least two direct drive wheels, wherein the at least two direct drive wheels comprise:

• a brushless direct current motor comprising:
• a cylindrical outer rotor having a plurality of poles positioned on an inner surface thereof,
• a stationary central shaft having:
• a central axial bore and at least one radial wire passthrough bore in communication with the central axial bore, wherein a passageway formed by the at least one radial passthrough bore and central axial bore provides passage of wires from the plurality of electromagnets to a motor controller, and
• at least three axial bores evenly spaced about and radially offset from the central axial bore, each of the at least three axial bores configured to accept an attachment element providing connection to the autonomous mobile robot,
• a stationary stator mounted to the central shaft so that the rotor is configured for rotation about the stator, wherein the stator is spaced inwardly from the rotor and includes a plurality of electromagnets positioned on an outer circumference thereof, wherein
• a distance between the plurality of poles of the rotor and the plurality of electromagnets defines a magnetic clearance gap, and
• a cover attachable to an outer circumferential edge of the rotor, wherein rotation of the rotor and the cover about the central shaft is permitted by bearings positioned therebetween;
• and
• a tire positioned on an outer circumferential surface of the rotor and covering the stator and the bearings,
• wherein the cover comprises an encoder magnet centrally located thereon, and the central shaft comprises an encoder read head positioned adjacent the encoder magnet, wherein wires from the encoder read head pass through the central bore and exit a side of the central bore opposite the cover,
• wherein the stator is mounted to the central shaft so that the rotor is configured for rotation about the stator, and
• wherein the plurality of poles are constructed of permanent magnets alternatively magnetized north and south.

An autonomous mobile robot comprising a motor controller, a battery, and at least two direct drive wheels, each direct drive wheel comprising:

• an inner stationary stator comprising a plurality of electromagnets positioned on an outer circumference thereof;
• a cylindrical outer rotor surrounding the inner stationary stator and including:
• a plurality of permanent magnets alternatively magnetized north and south and positioned on an inner circumferential surface of the rotor forming a magnetic clearance gap between the plurality of permanent magnets and the plurality of electromagnets, and
• a tire positioned on an outer circumferential surface of the rotor;
• and
• a stationary central shaft having a central axial bore, wherein the stator is mounted to the central shaft and the rotor is configured for rotation about the stator,
• wherein the motor controller is configured to provide power to groups of electromagnets of the plurality of electromagnets, and to apply a switching pattern to the groups to cause the outer rotor to rotate about the stator.