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 motor/encoder assembly for a tape drive comprising:
a motor housing;
a DC motor mounted in the housing, the DC motor having a rotor, a field magnet attached to the rotor, and laminations and windings;
a code wheel mounted on the rotor within the motor housing;
a code wheel sensor fixedly mounted within the motor housing;
a chuck mounting feature on one end of the rotor which extends outside the motor housing; and
a chuck locating feature on the chuck mounting feature.
2. The assembly of claim 1 , further comprising a printed circuit board mounted in the motor housing, the rotor extending axially through the printed circuit board.
3. A tape drive with a motor/encoder assembly, comprising:
a motor housing;
a DC brushless motor with driver circuits located entirely within the motor housing;
an encoder with encoder sensors located entirely within the motor housing; and
a tape cartridge driver mounting on the DC brushless motor.
4. The tape drive of claim 3 , wherein the cape drive has a 5¼ inch form factor.
5. The assembly of claim 1 , wherein the code wheel is a magnetic code wheel comprising a magnet-ring holder attached to the rotor, and a magnetic ring mounted to a surface of the magnetic-ring holder.
6. The assembly of claim 5 , wherein the magnet-ring is axially magnetized and has alternating north and south poles around the circumference of the magnet-ring.
7. The assembly of claim 1 , wherein the code wheel is an optical code wheel, and the code wheel sensor includes a U-shaped module with a light source and a sensor portion, positioned on the printed circuit board such that the optical code wheel passes the light source and the sensor portion.
8. A tape drive comprising:
a motor housing;
a DC motor mounted in the housing, the DC motor having a rotor, a field magnet attached to the rotor, and laminations and windings;
a code wheel mounted on the rotor within the motor housing;
a code wheel sensor fixedly mounted within the motor housing; and
means housed within the motor housing for coupling a rotor to a tape cartridge, rotating a tape cartridge wheel, and encoding a position of the rotor, the means including said rotor rotatably mounted within the motor housing; and
a printed circuit board stationary mounted in the motor housing, the sensor being mounted in motor housing on a top surface of the printed circuit board, and magnetic code wheel being mounted on the rotor axially above the top surface of the printed circuit board.
9. The tape drive of claim 8 , wherein the laminations and windings are positioned in the motor housing axially below the printed circuit board.
10. The assembly of claim 8 , wherein the code wheel is a magnetic code wheel comprising a magnet-ring holder attached to the rotor, and a magnetic ring mounted to a surface of the magnetic-ring holder.
11. The assembly of claim 10 , wherein the magnet-ring is axially magnetized and has alternating north and south poles around the circumference of the magnet-ring.
12. The assembly of claim 8 , wherein the code wheel is an optical code wheel, and the code wheel sensor includes a U-shaped module with a light source and a sensor portion, positioned on the printed circuit board such that the optical code wheel passes the light source and the sensor portion.