Disk Drive Suspension Microactuator Design for Vibration Control
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Solution Overview
Problem
Existing disk drive suspensions face issues with dynamic performance and shock absorption due to discontinuities and asymmetry caused by the non-central placement of piezo microactuators and stiffeners, which degrade modal frequencies and introduce out-of-plane vibration modes.
Innovation Solution
A microactuated disk drive suspension design where the microactuator is centrally placed on the longitudinal axis, integrated with the mount plate, and acts in its plane, eliminating the need for separable stiffeners and discontinuities, with a split mount plate and expandable gap to enhance shifting and vibration damping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the piezo microactuator is physically separated from the mount plate, then the microactuator can be positioned to provide actuation, but discontinuities and voids are formed that degrade dynamic performance and shock absorption
Solution Approach 1:
The microactuator is integrated directly into the mount plate structure, eliminating physical separations and the resulting discontinuities. The mount plate and microactuator form a unified structure that maintains structural integrity while providing the necessary actuation functionality, thereby preserving dynamic performance and shock absorption capabilities.
2Strength
If stiffeners are placed distally of the PZT, then shock absorption is improved, but the PZT is mechanically blocked and mechanical amplification is attenuated
Solution Approach 1:
The stiffener is repositioned from a distal location to a proximal location on the mount plate, adjacent to the microactuator body. This spatial reconfiguration allows the stiffener to provide shock absorption without interfering with the microactuator's mechanical amplification function, as the stiffener now supports the mount plate structure near the actuator rather than blocking its motion path.
3Ease of manufacture
If the microactuator is not centrally placed on the longitudinal axis, then manufacturing is simplified, but asymmetry causes out-of-plane vibration modes
Solution Approach 1:
The design intentionally incorporates symmetric placement of the microactuator on the longitudinal axis of the suspension. This symmetric configuration balances the mass distribution and actuation forces, preventing asymmetric vibration modes and ensuring stable operation, while the integrated mount plate design maintains manufacturing feasibility.
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
This design improves dynamic performance by maintaining modal frequencies and shock absorption capabilities while avoiding out-of-plane vibrations, allowing for precise and stable positioning of the slider.
Implementation Method 1
a microactuator which is a dimensionally variable body responsive to an applied voltage such as a piezoelectric crystal (PZT)
Implementation Method 2
a microactuator motor comprising a breathing mode PZT and a mount plate attaching the load beam to an actuator, the mount plate having a pocket receiving internally or externally the microactuator for deforming the mount plate in slider laterally displacing relation
Data Source
AI summary
A disk drive suspension has a load beam having a base, a flexure for carrying a slider, and a mount plate. The suspension mount plate has a first portion attachable to an actuator and movable by the actuator as the primary shifting force on the load beam, suitable for larger positioning movements. A second portion of the mount plate is attached to the load beam base and is movable relative to the mount plate first portion. A microactuator moves the second mount plate portion relative to the first mount plate portion as a secondary shifting force on the load beam, suitable for very small positioning movements.