Integrated Lead Head Suspension Flexure Neutral Axis Stress
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Solution Overview
Problem
Existing disk drive head suspension flexures experience high stresses and inadequate flexural characteristics due to the positioning of unbacked lead portions, which are not directly supported by the spring metal layer, leading to increased bending stresses and potential structural issues.
Innovation Solution
The integration of unbacked lead portions substantially inline with the spring metal layer, where at least part of the dielectric or lead portion is positioned between the surfaces of the spring metal layer, reducing bending stresses and improving flexural characteristics by locating the leads closer to the neutral axis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If unbacked lead portions are positioned away from the spring metal layer, then ease of manufacture is improved, but bending stresses and structural integrity worsen
Solution Approach 1:
The patent repositions the unbacked lead portions from a conventional elevated position to a location substantially inline with the spring metal layer, effectively changing the spatial dimension and vertical positioning of the leads. This dimensional reconfiguration allows the leads to be embedded within or adjacent to the spring layer thickness, reducing the moment arm and bending stresses while maintaining manufacturing feasibility through modified additive or subtractive processes
2Ease of manufacture
If unbacked lead portions are positioned away from the spring metal layer, then ease of manufacture is improved, but flexural characteristics worsen
Solution Approach 1:
By relocating the unbacked lead portions to a position substantially inline with the spring metal layer, the patent changes the vertical dimension and spatial arrangement of the flexure components. This repositioning reduces the distance from the neutral axis, thereby improving flexural characteristics and reducing bending moments during suspension operation, while still allowing for practical manufacturing through adapted fabrication sequences
3Reliability
If lead portions are positioned above the spring metal layer, then electrical connectivity is maintained, but bending stresses increase
Solution Approach 1:
The patent repositions the lead portions from above the spring metal layer to a location substantially inline with it, changing the vertical dimension and reducing the distance from the neutral axis. This reduces bending stresses during flexure operation while maintaining electrical connectivity through the lead's inherent conductivity and its new proximity to the spring layer, which can serve as a reference plane or support structure
Solution Approach 2:
The spring metal layer itself acts as an intermediary structure that provides both mechanical support and a reference plane for the repositioned lead portions. By placing the leads substantially inline with the spring layer, the spring layer serves as a mediator that reduces bending stresses while maintaining the electrical pathway, effectively combining structural and electrical functions in a single configuration
Data Source
AI summary
An integrated lead head suspension flexure including a plurality of integrated leads each including at least one lead portion unbacked by the flexure spring metal layer and configured to be substantially inline with the general plane of the spring metal layer. The leads are disposed on a dielectric layer including an unbacked dielectric layer portion having a surface positioned between the major surfaces of the spring metal layer.