Hard Drive Flexure Trace Overlap for Vibration Resistance
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Solution Overview
Problem
Current suspensions for hard disk drives face challenges in maintaining precise head positioning and stability under vibrations and surface irregularities, particularly due to limitations in the design of flexures and actuators, which affect the servo bandwidth and data seek times.
Innovation Solution
The design incorporates conductive traces with semi-circular portions overlapping an oblong circular feature, providing a reinforced support structure for the head slider, and includes a dielectric layer to insulate coppery alloy signal conductors, enhancing the PZT frequency response and reducing high-order gimbal torsion mode gain, thereby improving head positioning control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional flexure designs are used, then the structure is simpler, but the head positioning precision and stability deteriorate under vibrations
Solution Approach 1:
The flexure employs a composite structure combining a base layer with an overlapping trace layer. The base layer provides structural support while the trace layer, containing conductive traces and oblong circular features, enhances mechanical reinforcement and electrical connectivity. This composite approach improves head positioning precision and vibration resistance without excessive complexity increase.
Solution Approach 2:
The flexure is divided into distinct functional layers: a base layer for structural support and an overlapping trace layer for reinforcement and electrical functions. The trace layer is further segmented into multiple oblong circular features and conductive traces that can be independently optimized. This segmentation allows each layer to specialize in specific functions, improving overall performance.
2Productivity
If the servo bandwidth is increased, then the head positioning control is improved, but the susceptibility to vibrations increases
Solution Approach 1:
The flexure design modifies physical parameters including the dimensions and spacing of oblong circular features, the thickness and material properties of the base and trace layers, and the conductive trace configurations. These parameter changes optimize the mechanical stiffness and damping characteristics, enabling higher servo bandwidth while maintaining vibration resistance through carefully tuned structural properties.
3Stability of the object's composition
If a reinforced support structure is added, then the head positioning stability is improved, but the device complexity increases
Solution Approach 1:
The design merges structural reinforcement and electrical conductivity functions into a single integrated trace layer. The oblong circular features and conductive traces are formed in the same layer, eliminating the need for separate reinforcement structures. This merging approach improves head positioning stability while minimizing the increase in device complexity.
Solution Approach 2:
The trace layer serves multiple functions simultaneously: it provides mechanical reinforcement to the flexure structure, establishes electrical connections between components, and enhances the overall stiffness of the suspension system. This multi-functionality reduces the need for additional dedicated components, maintaining relative simplicity while improving stability.
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 configuration enhances the PZT frequency response, reduces susceptibility to vibrations, and increases the head positioning control loop bandwidth, resulting in lower data seek times and improved alignment over the data track.
Implementation Method 1
The conductive traces are insulated from the stainless steel using a dielectric layer
Data Source
AI summary
A flexure is described, which includes conductive traces extending from a proximal end of the flexure to a distal end of the flexure. The flexure also includes a plurality of outer gimbal struts configured to define an opening at the proximal end of the flexure. The flexure also includes an oblong feature extending into the opening, the oblong feature defines an aperture. The conductive traces include a first semi-circular conductive trace portion overlapping a first section of the oblong feature at a proximal end of the aperture extending to a distal end of the aperture. The conductive traces include a second semi-circular conductive trace portion overlapping a second section of the oblong feature at a proximal end of the aperture extending to the distal end of the aperture. The first and second semi-circular conductive trace portions define the aperture.