Dielectric Limiter for Disk Drive Suspension Assembly
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Solution Overview
Problem
Existing magnetic disk drive suspension assemblies face challenges in miniaturization due to the need for mechanical limiters that affect pivotal motion and require costly bending work, and existing tether-based limiters can impede motion, especially in smaller designs.
Innovation Solution
A dielectric limiter structure is introduced, comprising a metal layer with moving-side and fixing-side limiter coupling portions, where the dielectric limiter's gross length is greater than the between-coupling-portions distance, allowing it to exert tension only upon external impact, thus preventing further displacement without affecting the pivotal motion, and can be formed within the insulating layer without mechanical work.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanical limiter is used to prevent plastic deformation of the flexure assembly during impact, then impact resistance is improved, but the device complexity and manufacturing cost increase due to bending work and additional space requirements
Solution Approach 1:
The patent replaces the mechanical limiter structure with a dielectric layer formed through semiconductor manufacturing processes. Instead of using mechanical components that require bending work and assembly, the limiter function is achieved through a deposited dielectric material that provides both mechanical limitation and electrical insulation, thereby reducing device complexity and manufacturing cost.
Solution Approach 2:
The patent changes the material parameter from mechanical structures to dielectric materials, and changes the manufacturing process parameter from mechanical bending work to semiconductor deposition processes. This transformation simplifies the limiter structure while maintaining impact resistance functionality.
2Reliability
If a tether portion is used to limit the motion range of the flexure tongue, then impact resistance is improved, but the pivotal motion performance deteriorates due to suppression of motion
Solution Approach 1:
The patent applies the dielectric limiter locally at specific positions on the flexure tongue without creating continuous tether portions. The dielectric layer is formed only in regions where limitation is needed, allowing the flexure tongue to maintain free pivotal motion in areas where the dielectric layer is absent, thus preserving motion performance while providing impact resistance.
Solution Approach 2:
The patent uses partial action by forming the dielectric limiter only in specific locations rather than continuously across the entire flexure structure. This partial limitation approach allows sufficient pivotal motion while still providing adequate impact resistance where the dielectric layer is present.
3Volume of moving object
If the suspension assembly is miniaturized, then the volume is reduced, but the pivotal motion performance is more significantly affected by tether-based limiters
Solution Approach 1:
The patent replaces mechanical tether portions with a dielectric layer formed through deposition processes, which can be precisely controlled in thickness and location. This substitution enables miniaturization of the suspension assembly while maintaining pivotal motion performance, as the dielectric layer does not create the same motion suppression effects as mechanical tethers would in a miniaturized context.
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 dielectric limiter enables miniaturization of suspension assemblies by maintaining pivotal motion performance while providing impact resistance, preventing plastic deformation at higher accelerations, and reducing manufacturing costs by eliminating the need for mechanical work.
Implementation Method 1
the dielectric limiter's gross length is greater than the between-coupling-portions distance, allowing it to exert tension only upon external impact
Data Source
AI summary
Embodiments of the present invention provide a suspension assembly having a dielectric limiter. According to one embodiment, the suspension assembly includes a load beam and a flexure assembly. The flexure assembly includes a metal layer where there are formed a fixing portion fixed to the load beam, main rings, and extending from the fixing portion, sub-rings, and a flexure tongue having moving-side limiter coupling portions defined thereon. Fixing-side limiter coupling portions are defined at the main rings. Dielectric limiters each have a gross length larger than a between-coupling-portions distance between a fixing-side limiter coupling portion and a moving-side limiter coupling portion, and couple the fixing-side limiter coupling portion to the moving-side limiter coupling portion.