Dynamic magnetic information storage or retrieval – Head mounting – For adjusting head position
Patent
1997-05-01
2000-08-22
Evans, Jefferson
Dynamic magnetic information storage or retrieval
Head mounting
For adjusting head position
G11B 555, G11B 2110
Patent
active
061081752
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a microactuator for a disc drive system, and more particularly to a bimorph piezoelectric microactuator motor integrated into a head and flexure assembly.
The recording density of radial data tracks required in high performance disc drives continues to increase, necessitating higher resolution in head micropositioning devices to accommodate the decreased track pitch. Conventional actuators, utilizing a voice coil motor (VCM) for example, lack the precision to achieve the resolution required. Hence, an additional microactuator capable of adjusting the position of the head across several radial tracks with high precision must be implemented in the disc drive.
A number of solutions have been proposed to effect fine movement of the transducing head. The microactuator proposals have taken several forms, including a micro-motor attached directly to the slider and a piezoelectric microactuator implemented at the head mounting block connecting the head suspension to the actuator arm. However, no universally acceptable microactuator design has been found that combines manufacturing simplicity with superior performance characteristics, including a high movement-to-applied-voltage ratio, sufficient force for a given movement, and sufficient frequency response of the microactuator.
Thus, there is a need in the art for a microactuator design that is simple to manufacture and provides superior performance characteristics.
SUMMARY OF THE INVENTION
The present invention is a head flexure assembly for positioning a transducing head over a selected track of a rotatable disc in a disc drive system having an actuator arm and head suspension. The head flexure assembly includes a bimorph piezoelectric microactuator having first and second ends. The first end of the microactuator is attached to the head suspension, and a flexure is attached to the second end of the microactuator. A slider carrying the transducing head is attached to the flexure.
In one embodiment, the first end of the microactuator is clamped by swaged flaps of a swage plate, which is itself attached to the head suspension. In one form of this embodiment, the flexure includes swaged flaps connected to the second end of the microactuator.
According to another aspect of the invention, the bimorph piezoelectric microactuator includes first and second piezoelectric layers and a metal shim attached between the piezoelectric layers. A first conductive layer covers the first piezoelectric layer, and a first insulating coating covers the first conductive layer. A second conductive layer covers the second piezoelectric layer, and a second insulating coating covers the second conductive layer.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top view of a disc drive actuation system for positioning a slider over tracks of a disc.
FIG. 2 is a perspective view of a head and flexure assembly with a swaged bimorph piezoelectric microactuator according to the present invention.
FIG. 3 is a top view of the bimorph piezoelectric microactuator shown in FIG. 2.
FIG. 4 is a top view of an alternative embodiment of the piezoelectric microactuator shown in FIG. 2.
FIG. 5 is a top view of the head and flexure assembly having the swaged bimorph piezoelectric microactuator shown in FIG. 2, further showing an exemplary configuration of flexible wires for connection to the transducing head and the piezoelectric microactuator.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 is a top view of a disc drive actuation system 10 for positioning slider 24 over a track 34 of disc 30. Actuation system 10 includes voice coil motor (VCM) 12 arranged to rotate actuator arm 16 around axis 14. Head suspension 18 is connected to actuator arm 16 at head mounting block 20. Flexure 22 is connected to an end of head suspension 18, to fly slider 24 a small distance above the surface of disc 30. Slider 24 carries a transducing head (not shown in FIG. 1) for reading and/or writing data on tracks 34 of disc 30. Disc 30 rotates around ax
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Barina Jeffrey G.
Fard Anoush M.
Hawwa Muhammad A.
Mohajerani Khosrow
Sampietro Joseph M.
Evans Jefferson
Seagate Technology Inc.
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