Claims
- 1. A brushless, bidirectional, pure torque generating, electromechanical rotary actuator for random access, rapid positioning, along an arc of less than 90 degrees of a data transducer assembly among preselected ones of concentric data tracks of a rotating data storage disk, said actuator comprising:
- a base plate,
- a lower flux return plate secured to said base plate,
- permanent magnet means secured to said lower flux return plate for providing an even number plurality of adjacently opposed field magnetic field segments in which the north and south poles alternate at the major surfaces thereof,
- a stationary shaft connected to said base plate and extending vertically perpendicular to said base plate through the center of said lower flux return plate and said permanent magnet means,
- a hub rotatably mounted to said shaft,
- a coil assembly secured to said rotatable hub and closely spaced from said permanent magnet means, said coil assembly containing the same even number plurality of coils as there are magnet segments in said permanent magnet means, said coils being aligned adjacent to said magnetic segments at at least one position of rotation of said assembly, said coils being connected into two series of opposed windings equidistantly and symmetrically located about said assembly,
- an upper flux return plate secured to said base plate parallel to said permanent magnet means defining therebetween an annular space for said coil assembly and closely spaced to said coil assembly,
- a data transducer carriage connected to said hub and having a data transducer secured to its distal end, and
- a counterweight secured to said hub on the opposite side of said data transducer carriage to balance the weight thereof, whereby energizing said coils causes pure torque to be applied to said hub rotating said rotor arm and positioning said data transducer relative to said rotating data storage disk.
- 2. The electromechanical rotary actuator set forth in claim 1 wherein said coil assembly has been rotationally aligned relative to said permanent magnet means to linearize torque amplitude over the range of said arc.
- 3. The electromechanical rotary actuator set forth in claim 1 wherein said upper and lower flux return plates and said permanent magnet means are generally annular and wherein each said coil is formed of a generally triangular shape and wherein said coils are adjacent to each other within said rotatable coil assembly to form an annular coil plate assembly.
- 4. The electromechanical rotary actuator set forth in claim 3 wherein said assembly comprises coils connected into two sets, a first set comprising at least three non-adjacent coils connected in series in a first phase, and a second set comprising at least three non-adjacent coils connected in series in a second phase opposite to said first phase.
- 5. The electromechanical rotary actuator set forth in claim 4 wherein said first set and said second set have one common electrical connection which defines said first phase and said second phase.
- 6. The electromechanical rotary actuator set forth in claim 5 wherein said coils are formed of a single continuous wire strand.
- 7. The electromechanical rotary actuator set forth in claim 3 wherein said coil assembly comprises a molded disk containing said even number plurality of coils.
Parent Case Info
This application is a division of U.S. Pat. application No. 190,198 filed on Sept. 24, 1980, now U.S. Pat. No. 4,396,959.
US Referenced Citations (10)
Foreign Referenced Citations (1)
Number |
Date |
Country |
2029051A |
Mar 1980 |
GBX |
Non-Patent Literature Citations (2)
Entry |
Morgenthaler, M. P. and Weber, Lynn, "Servo-Controlled Beam Director Provides Major Benefits", Hewlett-Packard Journal, Feb. 1980, pp. 24-28. |
Stickel, "New 50-Megabyte Disc Drive: High Performance and Reliability from High Technology Design", Hewlett-Packard Journal, Aug. 1977, pp. 2-15. |
Divisions (1)
|
Number |
Date |
Country |
Parent |
190198 |
Sep 1980 |
|