Direct drive inside-out brushless roller motor
AssigneeAspen Motion Technologies, Inc.
InventorsMoe K. Barani, Ron Flanary, Lee Snider
Life of this patent
Estimating the term…
Abstract
A brushless d.c. motor is integrated with a conveyor roller (14) by placing a plurality of stator coils (15) on a stationary shaft (18) and securing a rotor (10) with segments (12) of permanent magnetic material to the inside of the conveyor roller (14). In one embodiment the rotor (10) is directly secured to the roller while in a second embodiment, the rotor (10) is disposed inside of a cylindrical metal housing (40) that is press fit inside of the roller. Commutation is provided by an external motor controller (54) which is connected by conductors (37) through a passageway (36) in the shaft (18) to a circuit board (20), where sensors (23) are mounted to sense rotor position for purposes of commutation of the stator coils (15).
Claims10
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.
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 conveyor roller extends beyond said second one of said bearings and to a greater length than the brushless d.c. motor, and further comprising a third bearing disposed beyond said second one of said bearings and proximate the second end of the conveyor roller for rotatably supporting the conveyor roller;
- 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.
Dependencies are inferred from the claim text.