Segmented Self-Drilling Fastener for Faster Drilling and Pullout
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Solution Overview
Problem
There is a need for self-drilling self-tapping fasteners that improve drilling time and pullout force without compromising ductility, tapping torque, torsional strength, or tensile strength.
Innovation Solution
The self-drilling self-tapping fastener features a head, shank, and helical thread formation with a drill tip and flutes, including chip breakers, optimized through milling or forging, to enhance drilling efficiency and pullout force while maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional self-drilling self-tapping fastener designs are used, then manufacturing is simpler, but drilling time increases and pullout force decreases
Solution Approach 1:
The shank is divided into multiple portions (first shank portion, second shank portion, third shank portion) with distinct functions. The second shank portion specifically includes flutes and chip breakers for enhanced chip evacuation, while other portions have different configurations. This segmentation allows optimization of drilling performance in specific zones without unnecessarily complicating the entire shank structure.
Solution Approach 2:
Different portions of the shank have different local characteristics tailored to specific functions. The second shank portion has deeper flutes and chip breakers for aggressive chip removal during drilling, while the first and third portions have simpler configurations suitable for their respective roles in thread formation and structural support.
2Force
If conventional self-drilling self-tapping fastener designs are used, then device structure is simpler, but pullout force decreases
Solution Approach 1:
The helical thread formation is segmented into different zones along the shank portions. The first shank portion has threads optimized for initial engagement, the second shank portion has threads配合flutes and chip breakers for enhanced engagement in challenging materials, and the third shank portion has threads for final securing. This segmented approach distributes the load and improves overall pullout force.
Solution Approach 2:
The fastener employs a composite structure combining different geometric features (flutes, chip breakers, varied thread pitches) along the shank length, creating a functionally composite design that optimizes both drilling performance and pullout force without requiring different materials.
3Productivity
If drilling time is reduced through aggressive drilling features, then productivity improves, but ductility and torsional strength may decrease
Solution Approach 1:
The shank is segmented so that the second portion with aggressive drilling features (deep flutes, chip breakers) is localized, while the first and third portions maintain simpler, stronger structures. This limits the impact of aggressive drilling features to only where needed, preserving overall torsional strength and ductility of the fastener.
Solution Approach 2:
The flute depth, chip breaker geometry, and thread pitch are optimized within specific parameter ranges that balance chip evacuation efficiency with structural integrity. The parameters are tuned to achieve adequate drilling performance without过度 removing material that would compromise torsional strength and ductility.
Data Source
AI summary
A self-drilling self-tapping fastener that provides improved performance in both drilling time and pullout force without decreasing performance in any of ductility, tapping torque, torsional strength, and tension strength.