Axial-Recess Self-Piercing Rivet for Thin Aluminum Panel Joining
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Solution Overview
Problem
Existing self-piercing rivets 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 effective 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
1Strength
If self-piercing rivets are used for thin aluminum panels, then joining quality and load-bearing capacity are improved, but manufacturing complexity and process difficulty increase
Solution Approach 1:
The patent applies parameter changes by optimizing the recess volume ratio to a specific range (6-8% of total rivet volume) and controlling the axial depth ratio (0.1-0.3 times shank diameter). These precise parameter adjustments enable the rivet to achieve high joining quality for thin aluminum panels while maintaining manufacturability through controlled deformation during the riveting process.
Solution Approach 2:
The axial recess creates a local quality difference in the rivet structure, concentrating deformation capacity in the recess region while maintaining structural integrity elsewhere. This localized design allows the rivet to adapt to thin panel thickness variations without requiring complex overall structural changes.
2Strength
If self-piercing rivets are used for thin aluminum panels, then joining quality and load-bearing capacity are improved, but adaptability to different panel thicknesses deteriorates
Solution Approach 1:
The axial recess provides dynamic adaptability by allowing the rivet to deform and adjust its shape during the riveting process. This dynamic deformation capability enables the same rivet design to effectively join panels of varying thin thicknesses, as the recess accommodates different material displacement requirements based on panel thickness.
Solution Approach 2:
By optimizing the recess volume ratio and axial depth parameters, the rivet design achieves adaptability across a range of thin panel thicknesses. The controlled deformation characteristics allow the rivet to self-adjust during setting, maintaining effective joining quality without requiring multiple specialized rivet designs for different thicknesses.
3Ease of manufacture
If self-piercing rivets are used instead of resistance spot welding, then manufacturing simplicity is improved, but joining quality for thin panels deteriorates
Solution Approach 1:
The optimized recess volume ratio (6-8%) and axial depth parameters enable the self-piercing rivet to achieve joining quality comparable to resistance spot welding while maintaining the manufacturing simplicity of mechanical fastening. The parameter optimization ensures adequate deformation capacity for thin panels without requiring heat treatment or complex equipment.
Solution Approach 2:
The invention replaces the thermal process of resistance spot welding with a mechanical deformation process. The optimized axial recess geometry enables controlled plastic deformation that creates reliable mechanical interlocking, substituting thermal energy with mechanical energy while achieving comparable joining quality for thin aluminum panels.
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 described rivet geometry enhances joining quality and load-bearing capacity, making it suitable for thin aluminum panels while maintaining the manufacturing advantages of clinch rivets, thus competing effectively with other joining methods.
Implementation Method 1
the shank deforms outwardly to interlock with the material
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.