Self-Piercing Rivet Recess Geometry for Thin Aluminum Joining
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Solution Overview
Problem
Current self-piercing rivet technologies face challenges in achieving high joining quality and adaptability for thin aluminum panels, particularly in vehicle door applications, where they compete with other methods like resistance spot welding.
Innovation Solution
A self-piercing rivet with a specific geometry characterized by an axial recess volume ratio between 0.06 and 0.08, allowing for efficient piercing and interlocking of thin sheet metals without the need for pre-drilling or heat treatment, thus enabling easy manufacturing and high joining quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a self-piercing rivet with conventional geometry is used for thin aluminum panels, then the joining operation can be performed, but the joining quality is insufficient and competes poorly with resistance spot welding
Solution Approach 1:
The patent applies parameter changes by optimizing the recess volume ratio to a specific range (0.04-0.12) and adjusting the axial depth ratio (0.08-0.25) to achieve optimal joining quality for thin aluminum panels. This quantitative parameter optimization resolves the contradiction between maintaining reliable joining and adapting to thin panel applications.
Solution Approach 2:
The patent implements local quality by creating a specific recess geometry at the foot end of the shank with controlled volume and depth ratios. This localized structural modification enables the rivet to achieve both high joining quality and adaptability to thin panels through optimized material deformation in the recess region.
2Reliability
If a self-piercing rivet with optimized geometry for thin panels is developed, then joining quality improves, but the manufacturing complexity increases
Solution Approach 1:
The patent resolves the contradiction between joining quality and manufacturing complexity by defining specific parameter ranges for the recess geometry (volume ratio 0.04-0.12, axial depth ratio 0.08-0.25). These quantified parameters enable standardized manufacturing processes while achieving optimized joining performance, avoiding excessive geometric complexity.
3Strength
If a self-piercing rivet with larger recess volume is used, then the interlocking capability improves, but the manufacturing cost and process complexity increase
Solution Approach 1:
The patent optimizes the recess volume ratio to a specific range (0.04-0.12) that balances interlocking capability with manufacturing simplicity. This parameter optimization ensures sufficient load-bearing capacity while maintaining ease of manufacture by avoiding excessive recess volumes that would increase manufacturing complexity and cost.
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 proposed rivet geometry enhances joining quality and load-bearing capacity, making it suitable for thin aluminum panels, while also simplifying the manufacturing process and reducing costs, thus competing effectively with other joining methods.
Implementation Method 1
the shank is caused to flare outwardly. The sheets of material are caused to deform around the shank, creating an annulus that encapsulates the shank
Data Source
AI summary
A self-piercing rivet with a head and a shank which has a shank diameter (Ds), wherein, at a foot end opposite the head, the shank has an axial recess which has an axial depth (LB), wherein the axial recess has a recess volume, wherein a ratio of recess volume to volume of the shank and the head is in the range of 0.06 to 0.08.