Unitary synchronous flexure microactuator

Details Unitary synchronous flexure microactuator Unitary synchronous flexure microactuator

1999-04-09

2001-04-10

Cao, Allen T. (Department: 2754)

Dynamic magnetic information storage or retrieval

Head mounting

For adjusting head position

Reexamination Certificate

active

06215629

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a disc drive microactuator, and more particularly to a high resolution head positioning mechanism that eliminates the need for hinges or linkages to finely position the head over a selected track of a rotating disc.
The density of concentric data tracks on magnetic discs continues to increase (that is, the width of data tracks and radial spacing between data tracks are decreasing), requiring more precise radial positioning of the head. Conventionally, head positioning is accomplished by operating an actuator arm with a large-scale actuation motor, such as a voice coil motor, to radially position a head on a flexure at the end of the actuator arm. The large-scale motor lacks sufficient resolution to effectively accommodate high track-density discs. Thus, a high resolution head positioning mechanism, or microactuator, is necessary to accommodate the more densely spaced tracks.
One promising design for high resolution head positioning involves employing a high resolution microactuator in addition to the conventional lower resolution actuator motor, thereby effecting head positioning through dual-stage actuation. Various microactuator designs have been considered to accomplish high resolution head positioning. However, many of these designs require either deformation of the disc drive flexure or load beam to achieve small displacement of the head or the implementation of hinges or linkages to transfer movement of the microactuator motor to the head itself In order to accommodate the additional bending modes of the disc drive components or the lack of synchronism between a microactuator motor and the actual movement effected by the head, it is typically necessary to redesign the servo system to have substantially greater bandwidth, which requires significant additional design time and expense. Additionally, implementation of a hinge or lever places strict constraints on the stress forces that can be accommodated by the disc drive structure. There is a need in the art for an effective disc drive microactuator that provides the ability to finely position a disc drive head over a selected track without deforming disc drive components or requiring hinges or linkages to translate movement of the microactuator to the slider.
BRIEF SUMMARY OF THE INVENTION
The present invention is a dual-stage actuation assembly for a disc drive. The dual-stage actuation assembly includes a movable actuator arm and a load beam connected to the actuator arm. A microactuator is attached to the load beam, and includes a first and second bending motor. The first bending motor has a first end, a second end and a longitudinal center between the first and second ends. The first bending motor is responsive to control signals to bend and thereby displace the longitudinal center in a selected direction. The second bending motor has a first end, a second end and a longitudinal center between the first and second ends. The second bending motor is responsive to control signals to bend complementary to the first bending motor and thereby displace the longitudinal center in the selected direction. A slider support structure supporting the slider over the disc is attached to the longitudinal centers of the first and second bending motors. The transducing head supported by the slider is therefore translationally moved across the tracks of the disc to achieve high resolution positioning in addition to the coarse positioning effected by movement of the actuator arm.


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