Modular gearless motorized conveyor roller

• US 6,244,427 B1
• Filed: 08/12/1999
• Issued: 06/12/2001
• Est. Priority Date: 09/16/1997
• Status: Expired due to Fees

• Current Assignee: Skarlupka Mfg., Inc.
• Original Assignee: Motion Systems LLC
• Inventors: Syverson, Charles D.
• Primary Examiner(s): Ellis, Christopher P.
• Assistant Examiner(s): Deuble, Mark A.
• Application Number:
  US09/373,481
• Time in Patent Office: 670 Days
• Field of Search: 198/784, 198/788, 198/781.05, 198/781.06, 310/156, 310/261, 310/267
• US Class Current: 198/788
• CPC Class Codes: B65G 13/06 Roller driving means
• CPC Class Codes: B65G 2207/30 Modular constructions
• CPC Class Codes: B65G 23/08 with self-contained driving mechanisms, e.g. motors and associated gearing
• CPC Class Codes: H02K 2207/03 Tubular motors, i.e. rotary motors mounted inside a tube, e.g. for blinds
• CPC Class Codes: H02K 7/1016 Machine of the outer rotor type

Abstract

A drive roller has a brushless D.C. motor with a stator or armature mounted on a fixed shaft and directly driving a 16 pole permanent magnet rotor mounted inside a roller tube. A motor controller drive supplies three-phase power to a Y-connected three phase winding having three groups of two coils, forming twelve electromagnets which drive the rotor. The modular motor is readily built in one inch increments to supply one lb-in of torque for each increment. The controller operates at a relatively low frequency of 15-75 Hz. Hall effect sensors provide feedback on motor speed and position. The armature laminations are relatively thick because of the relatively low power necessary to drive the motor and the resultant relatively low eddy currents present in the motor core. A 4.0 lb-in torque motor with a rotor and stator length of four inches will draw approximately 0.8 amps consuming about 15 Watts.

Claims

1. A roller conveyor system comprising:

a frame;

a multiplicity of idler rollers positioned for rotation on the frame;

a plurality of drive rollers positioned on the frame, each drive roller having a shaft fixed against rotation to the conveyor frame;

a stator having a core and at least three windings on the core, the stator being mounted about the shaft, the stator mounted about the rigid shaft;

a roller tube surrounding the shaft and the stator, and having a first and a second end and an interior, two tube closures, one tube closure rigidly mounted to each of the first end and the second end of the roller tube, wherein the tube closures are rotatably mounted on the shaft, to rotatably mount the roller tube on the shaft; and

a permanent magnet rotor having a plurality of poles, the rotor fixedly mounted to the roller tube interior and overlying and coaxial with the stator, the permanent magnet rotor and the stator forming a brushless three-phase D.C. motor, with the rotor and connected roller tube being driven by changes in induced magnetic fields in the stator;

at least one magnetic field sensor mounted on each stator and positioned to detect passage of the permanent magnets about the fixed shaft;

a plurality of three-phase power supply motor controllers for controlling the rotation speed of each drive roller, each motor controller arranged to utilize the output from the at least one magnetic field sensor mounted on each stator for commutation and speed control, each motor controller connected to one of said multiplicity of drive rollers for controlling the rotation speed of the connected drive roller rotor; and

a programmable controller operably connected to the motor controllers to control the speed of all the drive rotors.

2. The roller conveyor system of claim 1 wherein the permanent magnetic rotor is constructed of a plurality of cylindrical segments, each segment constructed of ferromagnetic particles embedded in a flexible matrix, and wherein the plurality of poles is imposed on said cylindrical segment.

3. The roller conveyor system of claim 2 wherein the cylindrical segments have alignment means for aligning the plurality of poles imposed on each segment.

4. The roller conveyor system of claim 2 wherein the ferromagnetic particles are composed of an alloy of NdFeB.

5. The roller conveyor system of claim 1 wherein the ratio between the permanent magnetic poles and the number of poles produced by energizing the windings of the stator is a ratio of 4:

3.

6. The roller conveyor system of claim 1 wherein six windings are employed on the stator and are arranged to induce twelve poles when energized.

7. The roller conveyor system of claim 1 wherein the roller tube has an exterior surface having a diameter of about 1.9 inches.

8. The roller conveyor system of claim 1 wherein the shaft has an extension which is slidably mounted on the shaft and biased in an extended position by a spring.

9. A drive roller adapted for use in a roller conveyor, the drive roller comprising:

a shaft adapted for rigid mounting to a conveyor support;

a stator having a core and plurality of windings on the core, the stator being mounted about the shaft;

a roller tube surrounding the shaft and the motor stator, the roller tube having an interior and having a first end and a second end and an exterior surface having a diameter of about 1.9 inches;

two tube closures, one rigidly mounted to each of the first end and the second end of the roller tube, wherein the tube closures are rotatably mounted on the shaft so that the roller tube rotates on the shaft; and

a permanent magnet rotor having a plurality of poles, which alternate North South, the rotor fixedly mounted to the roller tube interior and over and coaxial with the stator, the permanent magnet rotor and the stator forming a brushless D.C. motor, such that the rotor and fixedly mounted roller tube are driven by changes in induced magnetic fields in the stator, wherein six windings are employed on the stator and are arranged to induce twelve poles when energized.

10. A drive roller adapted for use in a roller conveyor, the drive roller comprising:

a shaft adapted for rigid mounting to a conveyor support;

a stator having a core and plurality of windings on the core, the stator being mounted about the shaft;

a roller tube surrounding the shaft and the motor stator, the roller tube having an interior and having a first end and a second end and an exterior surface having a diameter of about 1.9 inches;

two tube closures, one rigidly mounted to each of the first end and the second end of the roller tube, wherein the tube closures are rotatably mounted on the shaft so that the roller tube rotates on the shaft; and

a permanent magnet rotor having a plurality of poles, which alternate North South, the rotor fixedly mounted to the roller tube interior and over and coaxial with the stator, the permanent magnet rotor and the stator forming a brushless D.C. motor, such that the rotor and fixedly mounted roller tube are driven by changes in induced magnetic fields in the stator, wherein the permanent magnet rotor is constructed of a plurality of cylindrical segments, each segment constructed of ferromagnetic particles embedded in a flexible matrix, and wherein the plurality of poles is imposed on said cylindrical segment.

11. The drive roller of claim 10 wherein the cylindrical segments have alignment means for aligning the plurality of poles imposed on each segment.

12. The drive roller of claim 10 wherein the ferromagnetic particles are composed of an alloy of NdFeB.

13. A drive roller and roller controller for a roller conveyor comprising:

a shaft mounted fixedly against rotation to a conveyor support;

a stator having a core and at least three windings on the core, the windings producing a plurality of magnetic poles when energized, the stator being mounted about the shaft;

a roller tube surrounding the shaft and the stator, the roller tube having an interior, a first end and a second end, and an exterior surface;

a first tube closure mounted to the roller tube first end, and a second tube closure mounted to the roller tube second end, the tube closures being rotatably mounted on the shaft to rotatably mount the roller tube on the shaft;

a permanent magnet rotor having a plurality of poles which alternate North and South, the rotor being fixedly mounted to the roller tube interior and overlying and coaxial with the stator, the rotor and the stator forming a brushless three-phase motor, with the rotor and the fixedly mounted roller tube being driven by changes in induced magnetic fields in the stator; and

a source of power having three phases of drive current connected to the windings of the stator for controlling the rotation speed of the rotor, wherein the roller tube is comprised of two portions;

a first tube portion having a closed end which accommodates an intermediate bearing to rotatably mount the closed end to the shaft, the closed end having portions forming an opening through which the shaft extends; and

a second roller tube portion forming an extension of the first tube portion the second portion overlapping a portion of the first tube portion to form an interference fit with the first tube portion.

14. The drive roller of claim 13 wherein the exterior surface has a diameter of about 1.9 inches.

15. A drive roller and roller controller for a roller conveyor comprising:

a shaft mounted fixedly against rotation to a conveyor support;

a stator having a core and at least three windings on the core, the windings producing a plurality of magnetic poles when energized, the stator being mounted about the shaft;

a roller tube surrounding the shaft and the stator, the roller tube having an interior, a first end and a second end, and an exterior surface having a diameter of about 1.9 inches;

a first tube closure mounted to the roller tube first end, and a second tube closure mounted to the roller tube second end, the tube closures being rotatably mounted on the shaft to rotatably mount the roller tube on the shaft;

a permanent magnet rotor having a plurality of poles which alternate North and South, the rotor being fixedly mounted to the roller tube interior and overlying and coaxial with the stator, the rotor and the stator forming a brushless three-phase motor, with the rotor and the fixedly mounted roller tube being driven by changes in induced magnetic fields in the stator; and

a source of power having three phases of drive current connected to the windings of the stator for controlling the rotation speed of the rotor, wherein the permanent magnet rotor is constructed of a plurality of cylindrical segments, each segment constructed of ferromagnetic particles embedded in a flexible matrix, and wherein the plurality of poles is imposed on said cylindrical segment.

16. The apparatus of claim 15 wherein the cylindrical segments have alignment means for aligning the plurality of poles imposed on each segment.

17. The apparatus of claim 15 wherein the ferromagnetic particles are composed of an alloy of NdFeB.

18. A drive roller adapted for use in a roller conveyor, the drive roller comprising:

a shaft adapted for rigid mounting to a conveyor support;

a stator having a core and plurality of windings on the core, the stator being mounted about the shaft;

a roller tube surrounding the shaft and the motor stator, the roller tube having an interior and having a first end and a second end and an exterior surface;

two tube closures, one rigidly mounted to each of the first end and the second end of the roller tube, wherein the tube closures are rotatably mounted on the shaft so that the roller tube rotates on the shaft; and

a permanent magnet rotor having a plurality of poles, which alternate North South, the rotor fixedly mounted to the roller tube interior and over and coaxial with the stator, the permanent magnet rotor and the stator forming a brushless D.C. motor, such that the rotor and fixedly mounted roller tube are driven by changes in induced magnetic fields in the stator, wherein the roller tube is comprised of two portions;

a first tube portion having a closed end which accommodates an intermediate bearing to rotatably mount the closed end to the shaft, the closed end having portions forming an opening through which the shaft extends; and

a second roller tube portion forming an extension of the first tube portion, the second portion overlapping a portion of the first tube portion to form an interference fit with the first tube portion.

19. The drive roller of claim 18 wherein the exterior surface has a diameter of about 1.9 inches.

20. A drive roller and roller controller for a roller conveyor comprising:

a shaft mounted fixedly against rotation to a conveyor support;

a stator having a core and at least three windings on the core, the windings producing a plurality of magnetic poles when energized, the stator being mounted about the shaft;

a roller tube surrounding the shaft and the stator, the roller tube having an interior, a first end and a second end, and an exterior surface having a diameter of about 1.9 inches;

a first tube closure mounted to the roller tube first end, and a second tube closure mounted to the roller tube second end, the tube closures being rotatably mounted on the shaft to rotatably mount the roller tube on the shaft;

a permanent magnet rotor having a plurality of poles which alternate North and South, the rotor being fixedly mounted to the roller tube interior and overlying and coaxial with the stator, the rotor and the stator forming a brushless three-phase motor, with the rotor and the fixedly mounted roller tube being driven by changes in induced magnetic fields in the stator; and

a source of power having three phases of drive current connected to the windings of the stator for controlling the rotation speed of the rotor, wherein six windings are employed on the stator and are arranged to induce twelve poles when energized.