Patent ID: 6710505
Filing Date: 2004-03-23
Classification: B65G,H02K

Abstract:
A motor for driving a cylindrical conveyor roller that rotates around a stationary shaft, said conveyor roller having a first end and a second end, the motor comprising:a cylindrical rotor disposed inside of and mounted to rotate with said cylindrical roller around said stationary shaft; wherein said rotor is formed of a plurality of longitudinal segments of permanent magnetic material, wherein said segments alternate orientation of north-south magnetic polarity in a radial direction to produce flux in flux path loops connecting pairs of the longitudinal segments; a plurality of stator coils mounted on said shaft for receiving current from an external power supply that commutates current in said stator coils; wherein said motor is a brushless d.c. motor; further comprising a cylindrical metal rotor housing forming a part of the rotor for receiving the segments of permanent magnetic material and for supporting the shaft and the stator coils in a motor assembly; wherein said motor assembly, including said cylindrical metal rotor housing, is disposed inside of and secured to said roller to rotate with the roller; wherein said motor is supported by two spaced apart bearings which space the rotor from the stator to form an air gap; and wherein a first one of said bearings is proximate the first end of the conveyor roller and wherein a second one of said bearings is spaced a distance away from said first one of said bearings to provide the air gap for spacing the rotor from the stator; and wherein said stationary shaft extends only between said first one of the bearings and said second one of the bearings, which is a distance less than a distance between said first end and said second end of said conveyor roller.