Self-Piercing Rivet Pre-Perforated Flat Element Dissimilar Material Joining
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Solution Overview
Problem
The existing punch rivet technologies face challenges in producing high-quality joint connections between components made of different materials, such as plastic and metal, due to their different deformation behaviors, leading to issues like fiber detachment and gap formation, which compromise the strength and service life of the joint.
Innovation Solution
A self-piercing punch rivet with a pre-punched flat support element that extends radially beyond the head radius, providing a compression effect through a hold-down device to support the joint connection, ensuring a satisfactory bond between the plastic cover layer and metal structural component, and can be easily integrated into existing manufacturing and joining processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a self-piercing rivet is used to join plastic and metal components, then the joining process is simplified and productivity is improved, but the different deformation behaviors of the materials cause fiber detachment and gap formation, reducing joint strength and reliability
Solution Approach 1:
A flat support element is introduced as an intermediary component between the self-piercing rivet and the plastic component. This support element has a larger surface area than the rivet head and distributes the compressive force over a wider area during the joining process, preventing excessive localized deformation that causes fiber detachment and gap formation, thereby improving joint quality while maintaining the efficiency of self-piercing riveting
Solution Approach 2:
The flat support element is pre-positioned on the rivet shank before the joining operation. This preliminary arrangement ensures that the support element is already in place to distribute forces correctly from the beginning of the joining process, preventing material deformation issues before they occur
2Reliability
If the rivet head radius is increased to distribute compressive forces, then joint quality improves, but the rivet size and device complexity increase
Solution Approach 1:
The force distribution function is segmented from the rivet head to a separate flat support element. This allows the rivet head to maintain its standard compact size while the flat support element provides the extended surface area needed for force distribution, separating the joining function from the force distribution function and avoiding increased device complexity
Solution Approach 2:
Instead of increasing the rivet head radius in the radial dimension, the solution extends the force distribution area axially by adding a flat support element that protrudes beyond the head radius. This dimensional transition allows force distribution without increasing rivet head size or structural complexity
3Strength
If a hold-down device is used to apply compressive forces, then joint strength is improved, but the manufacturing complexity and process time increase
Solution Approach 1:
The flat support element enables the joining system to self-regulate force distribution during the joining process. By providing a larger surface area that naturally distributes compressive forces, the system reduces the need for complex external hold-down devices and manual intervention, allowing the process to proceed with standard equipment while achieving improved joint strength
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 solution enhances the quality and strength of the joint connection by applying compressive forces effectively across the joint area, minimizing material deformation and fiber detachment, thus improving the reliability and durability of the connection between dissimilar materials.
Implementation Method 1
providing a compression effect through a hold-down device to support the joint connection
Data Source
Figure 1~2
Figure 3~4
Figure 5a~5d
AI summary
The present invention discloses a self-piercing rivet (10), particularly a semi-hollow self-piercing rivet, with a head (12) and a shank (14) as well as a pre-perforated flat element (30) that is arranged on the shank (14) and at least part of which extends radially relative to the head (12) beyond a head radius. A production method and a joining method for said self-piercing rivet with pre-perforated flat element are also described.