Piezoelectric microactuator suspension assembly with...

Details Piezoelectric microactuator suspension assembly with... Piezoelectric microactuator suspension assembly with...

1999-05-13

2001-05-15

Klimowicz, William (Department: 2754)

Dynamic magnetic information storage or retrieval

Head mounting

For adjusting head position

Reexamination Certificate

active

06233124

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to a suspension-level microactuator having an improved stroke length. More particularly, it relates to a microactuator located between a suspension and an actuator arm in a disc drive system having piezoelectric elements to selectively move a transducing head radially with respect to a rotatable disc.
The density of concentric data tracks on magnetic discs continues to increase (that is, the size 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 low resolution actuator motor, thereby effecting head positioning through dual-stage actuation. Various microactuator designs have been considered to accomplish high resolution head positioning. However, these designs all had shortcomings that limited the effectiveness of the microactuator. Many designs increased the complexity of designing and assembling the existing components of the disc drive, while other designs were unable to achieve the force and bandwidth necessary to accommodate rapid track access. Therefore, the prior designs did not present ideal microactuator solutions. More recent microactuator designs employ piezoelectric elements to effect movement of the suspension with respect to the actuator arm. This technique has proven effective but suffers from a small range of motion.
There is a need in the art for a piezoelectric microactuator design to provide efficient high resolution head positioning in a dual-stage actuation system that allows for a greater range of motion than current designs and that can be implemented by readily available manufacturing processes.
BRIEF SUMMARY OF THE INVENTION
The present invention is a microactuator for selectively altering a position of a transducing head carried by a slider in a disc drive system with respect to a track of a rotatable disc having a plurality of concentric tracks. The disc drive system includes a base for attachment to an actuator arm and a head suspension for supporting the slider over the rotatable disc. The microactuator includes a first electroactive element attached between the base and the head suspension and a first beam attached between the base and the head suspension. The first electroactive element is longitudinally deformable (by lengthening or shortening) in response to a voltage applied thereto. The first beam is flexible to permit movement of the head suspension with respect to the base.
The first electroactive element is disposed substantially perpendicular to a longitudinal centerline of the base. In one embodiment, the first electroactive element has a length exceeding one half the width of the base. This increased length provides an increased electroactive element stroke length which, in turn, allows for a greater range of motion of the transducing head.
In one embodiment, two electroactive elements are attached between the base and the head suspension, and a second beam is attached between the base and the head suspension. The second electroactive element is deformable in a direction complementary to deformation of the first electroactive element in response to a voltage applied thereto. The second beam is flexible to permit movement of the head suspension with respect to the base.
In another embodiment, two electroactive elements displosed substantially parallel to a longitudinal centerline are employed. The two electroactive elements extend into a cutout window portion of the base to allow for an increased length element.


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“Design, Fabrication, and Tes

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