Patent ID: 6244427
Filing Date: 2001-06-12
Classification: B65G,H02K

Abstract:
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; anda programmable controller operably connected to the motor controllers to control the speed of all the drive rotors.