Motor/encoder assembly for tape drives
View Patent ↗A magnetic/encoder assembly has a compact design and combines the features of motor, encoder and chuck locating feature within a single motor housing. The motor/encoder includes a DC brushless motor with an inner magnetic rotor. The motor windings and the commutation electronics are mounted towards the bottom side of a printed circuit board. The rotor of the motor is extended above the surface of the printed circuit board. The extended rotor provides a precision seat for the magnetic wheel with multiple poles. The top surface of the printed circuit board mounts the sensor for the encoder. The extension of the rotor provides the precision mounting surface of the cartridge driving chuck.
1. A tape drive comprising:
a rotor compartment;
means housed within the rotor compartment for coupling a rotor to a tape cartridge, rotating a tape cartridge reel, and encoding a position of the rotor, the means including said rotor rotatably mounted within the rotor compartment;
a magnetic code wheel attached to the rotor to spin with the rotor and located within the rotor compartment;
a magnetic code wheel sensor stationarily positioned within the rotor compartment, which senses rotation of the magnetic code wheel; and
a printed circuit board stationarily mounted in the rotor compartment, the sensor being mounted in the rotor compartment on the top surface of the printed circuit board, and the magnetic code wheel being mounted on the rotor axially above the top surface of the printed circuit board.
2. The tape drive of claim 1 , further comprising motor components within the rotor compartment axially below the bottom surface of the printed circuit board, including a field magnet mounted on the rotor, laminations and windings terminated at the bottom surface of the printed circuit board, and a commutation sensor mounted on the bottom surface of the printed circuit board.