Flexure-Integrated Piezo Microactuator for HDD Slider Positioning
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Solution Overview
Problem
Existing microactuators in hard disk drives face issues with cost, reliability, and fragility, and are limited by dynamic performance due to low frequency resonances and significant reaction forces, which affect the precise positioning of the recording head.
Innovation Solution
A piezo actuator design that selectively rotates the slider about a dimple axis, providing lateral motion in the 0.1 to 0.2 micron range, addressing the limitations of previous designs by maintaining low mass and similar manufacturing processes while enhancing precision and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional microactuators are used for head positioning, then cost and manufacturing are simplified, but reliability deteriorates due to fragility and low frequency resonances
Solution Approach 1:
The patent combines the microactuator functionality directly into the flexure structure itself, merging two previously separate components (microactuator and flexure) into a single integrated assembly. This integration eliminates the need for separate mounting structures and reduces overall device complexity while improving reliability by removing potential failure points at interfaces between separate components.
Solution Approach 2:
The flexure-integrated microactuator employs composite material construction, combining flexible materials with piezoelectric or magnetostrictive materials within the flexure structure. This allows the flexure to simultaneously provide mechanical flexibility and actuation functionality, achieving reliable positioning without increasing overall structural complexity.
2Manufacturing precision
If existing microactuators are used, then manufacturing processes are simpler, but manufacturing precision deteriorates due to limited positioning accuracy
Solution Approach 1:
The patent replaces conventional mechanical actuation mechanisms with piezoelectric or magnetostrictive materials embedded within the flexure. These materials convert electrical or magnetic signals directly into precise mechanical displacement, achieving sub-micron positioning accuracy (0.1 to 0.2 micron range) without complex mechanical assemblies, thereby maintaining ease of manufacture while dramatically improving positioning precision.
Solution Approach 2:
The invention utilizes materials that change their physical dimensions in response to electrical or magnetic field parameters. By applying controlled voltage or magnetic field changes, the flexure-integrated microactuator achieves precise slider positioning with resolution in the 0.1 to 0.2 micron range, significantly improving manufacturing precision while using standard flexure manufacturing processes.
3Productivity
If traditional actuators are used, then device mass is higher, but dynamic performance deteriorates due to significant reaction forces and low frequency resonances
Solution Approach 1:
The patent extracts the actuation functionality from separate heavy mechanical components and embeds it directly within the lightweight flexure structure. By removing the need for distinct actuator housings, mounting mechanisms, and separate drive assemblies, the design achieves high dynamic performance with minimal reaction forces while maintaining extremely low mass, as the flexure itself serves as both the flexible support and the actuator.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The piezo actuator design achieves precise slider positioning with improved reliability and reduced resonance issues, maintaining low mass and similar manufacturing costs, and enhances the dynamic performance of the hard disk drive by increasing resonant frequency above the second-stage actuator requirements.
Implementation Method 1
A piezo actuator design that selectively rotates the slider about a dimple axis
Implementation Method 2
A flexure mounted to the load beam and having a tongue with a leading edge portion and a slider attachment platform
Data Source
AI summary
A piezo in-tongue microactuator includes a suspension assembly with a flexure tongue. The tongue has two slots that accept piezo actuators. The tongue also has multiple hinge flexible elements that translate the extension and/or contraction of the piezo actuators into rotary motion of the recording head. This rotary motion is then used to precisely position the recording element over the desired track on the hard disk drive and permits higher track density to be achieved.