Laminate Suspension Arcuate Outer Layer for High Stroke Sensitivity
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Solution Overview
Problem
Current disk drive suspension designs face challenges in achieving both desired resonance frequency and stroke sensitivity, particularly in smaller form factors like the Pico and Femto formats, where stroke sensitivity is inadequate.
Innovation Solution
The design employs a laminate suspension with an outer layer bent into an arcuate shape, using a thin laminate layer as the spring to enhance bending resistance and stroke distance, and integrates a plastic inner layer for improved spring rate control, eliminating the need for welding and associated issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single element load beam is used, then manufacturing is simpler, but stroke sensitivity is insufficient
Solution Approach 1:
The patent applies composite materials by using a laminate structure consisting of multiple layers (first outer layer, inner layer, second outer layer) with different material properties. The first outer layer provides flexibility for stroke movement, the inner layer provides structural support, and the second outer layer provides stiffness. This composite structure enables high stroke sensitivity while maintaining manufacturability through layer-specific optimization.
Solution Approach 2:
The load beam is segmented into distinct functional layers: a first outer layer forming the suspension spring portion for flexibility, an inner layer for structural support, and a second outer layer for stiffness. This segmentation allows each layer to be optimized for its specific function, achieving high stroke sensitivity through the flexible first outer layer while maintaining overall structural integrity.
2Manufacturing precision
If etching to thickness is used to control spring rate, then spring rate can be adjusted, but heating distortions and production time increase
Solution Approach 1:
The patent controls spring rate by changing the thickness parameter of the first outer layer during the lamination process itself, rather than through subsequent etching. By adjusting the thickness of the first outer layer (which forms the suspension spring portion), the spring rate is precisely controlled without requiring additional heating or etching steps, thereby reducing production time and avoiding heating distortions.
Solution Approach 2:
The patent replaces the mechanical/thermal etching process with a material deposition approach. Instead of removing material through etching to control thickness and spring rate, the invention uses a lamination process where the first outer layer is deposited with the desired thickness directly, substituting a simpler, faster manufacturing method that avoids heating and distortion issues.
3Reliability
If welding is used to attach the spring, then attachment is achieved, but heating distortions and production costs increase
Solution Approach 1:
The patent merges the spring attachment function into the laminate structure itself. The first outer layer is continuous from the base portion through the suspension spring portion to the beam portion, creating an integral attachment without requiring separate welding steps. This merging eliminates heating distortions and reduces production time while maintaining reliable attachment through the inherent bonding of the laminated structure.
Solution Approach 2:
The patent substitutes the welding process with a lamination bonding process. Instead of using heat and pressure to weld separate metal pieces together, the invention uses adhesive bonding in the lamination process to attach the spring portion to the base and beam portions, eliminating the need for welding equipment, reducing production time, and avoiding welding-induced heating distortions.
4Length of moving object
If the suspension is made 11 mm long or less, then form factor is reduced, but stroke sensitivity becomes inadequate
Solution Approach 1:
The patent uses composite materials in the laminate structure to achieve high stroke sensitivity in a compact 11 mm or less suspension. The first outer layer provides flexibility for stroke movement, while the inner and second outer layers provide structural support, enabling the suspension to maintain adequate stroke sensitivity despite the reduced overall length.
Solution Approach 2:
The patent applies local quality by making the first outer layer (suspension spring portion) thinner and more flexible specifically at the regions requiring stroke movement, while maintaining adequate thickness in other regions for structural support. This localized variation in thickness allows the suspension to achieve high stroke sensitivity in the spring portion without compromising overall structural integrity in the compact form factor.
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 approach allows for high stroke sensitivity and controlled resonance frequency in microactuated disk drive suspensions, even in smaller formats, while avoiding production challenges like heating distortions and increased costs.
Implementation Method 1
Using an outer layer of a suspension laminate bent into an arcuate, 'C', shape eases bending resistance and results in greater stroke distance
Implementation Method 2
a microactuator operatively coupled between the base portion and the beam portion for laterally shifting the beam portion
Data Source
AI summary
A high stroke sensitivity microactuated disk drive suspension includes a microactuator, a laminate of first and second outer layers and a plastic inner layer that define a base portion, a spring portion and a beam portion. The base portion has proximate and distal regions coupled by a segment of an outer layer and fixed to the microactuator for relative shifting of the beam portion to the base portion. The segment has a part that is locally arcuate and readily bendable during said shifting for low resistance to shifting giving the suspension high stroke sensitivity.