Sandwich Vehicle Panel Riveting With Cold-Formed Collar Reinforcement
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Solution Overview
Problem
Commercial vehicle panels with thin metal cover layers face challenges in securely fastening components under significant loads without additional reinforcement, as existing blind rivet methods struggle to provide a permanent and secure hold, especially when no reinforcement plates are present.
Innovation Solution
The method involves cold-forming the edge region of the cover layer to create a collar that protrudes into the core layer, increasing the dimensional stability and strength of the edge area, allowing for secure fastening using blind rivets without additional reinforcement, enabling components to be attached at any point on the panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If blind rivets are used to fasten components to thin metal cover layers without additional reinforcement, then the fastening process is simplified and productivity is improved, but the strength and reliability of the fastening is insufficient under significant loads
Solution Approach 1:
The edge region of the cover layer is cold-formed into a collar shape before the blind rivet is installed. This preliminary action creates a geometric feature that mechanically interlocks with the rivet, providing enhanced fastening strength without requiring additional reinforcement plates or complex preparation steps. The collar is formed by inserting a mandrel through the cover layer and cold-forming the material around it.
Solution Approach 2:
The cold-forming process creates a collar with different geometric and mechanical properties than the surrounding cover layer material. The collar region has increased thickness and altered grain structure due to plastic deformation, providing localized strength enhancement precisely where the fastening is needed, while leaving the rest of the thin cover layer unchanged.
2Strength
If reinforcing plates are added to the cover layer to enable secure fastening, then the fastening strength is improved, but the device complexity and manufacturing effort increase
Solution Approach 1:
The invention extracts the reinforcement function from a separate component (reinforcing plate) and integrates it directly into the cover layer itself through cold-forming. By removing the need for additional reinforcement plates and reducing preparation steps, the solution simplifies the overall panel structure while maintaining the necessary fastening strength through the geometric collar feature.
Solution Approach 2:
The invention changes the geometric parameters of the cover layer edge region by cold-forming it into a collar shape. This parameter change—creating a protruding collar with specific dimensions—provides the mechanical interlock needed for strong fastening without adding separate reinforcement components, thereby reducing device complexity.
3Weight of moving object
If the cover layer is made thinner to reduce weight, then the vehicle weight is reduced, but the ability to securely fasten components under load is compromised
Solution Approach 1:
The cold-formed collar creates a localized region of increased thickness and strength at the fastening point, while the rest of the cover layer remains thin. This local quality enhancement allows the cover layer to maintain overall thinness for weight reduction while providing sufficient fastening capacity where needed through the geometric collar feature that mechanically interlocks with the blind rivet.
Solution Approach 2:
The invention creates a composite structure where the cold-formed collar region has different mechanical properties than the base cover layer material. The plastic deformation process alters the material structure in the collar region, creating a composite effect that combines the thinness of the original cover layer with the enhanced strength of the cold-formed region, enabling both weight reduction and adequate fastening capacity.
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
This approach enhances the strength and dimensional stability of the edge area, ensuring a permanent and secure hold of the riveting even without additional reinforcement, allowing for flexible and efficient attachment of components to vehicle panels with thin metal cover layers.
Implementation Method 1
the edge region of the cover layer surrounding the opening of the cover layer of the respective panel is at least partially cold-formed into a collar projecting into the core layer
Implementation Method 2
the rivet sleeve is formed into a closed head by drawing in the mandrel head. To rivet a component to sheet metal, the blind rivet is inserted from the accessible side of the component through an opening in the component to be fastened and a corresponding opening in the sheet metal
Implementation Method 3
The tensile force applied to the rivet mandrel compresses the rivet sleeve in the inaccessible area, shielded by the sheet metal, and deforms it into a rivet head
Data Source
Figure 1
Figure 2a
Figure 2b
AI summary
The invention provides a structure for a commercial vehicle comprising a wall or roof element (1) formed by a panel (2,3) in the manner of a sandwich, consisting of a foamed core layer (6) and at least one cover layer (4,5) made of a deformable material, which covers the core layer (6) on one of its side surfaces, and wherein a component (9) is attached to the outer surface (7) of the cover layer (4,5) facing away from the core layer (6) by means of a riveting using a blind rivet (10) which sits in openings (20,31) provided in the component (9) and the cover layer (4,5) in alignment with each other.In such a structure, a component can be permanently and securely fastened at any point on the surface layer of the panels forming the wall or ceiling elements of the structure by means of blind rivets. This is achieved by cold-forming, at least in sections, the edge region (21) of the surface layer (4, 5) surrounding the opening (20) of the surface layer (4, 5) into a collar (30) projecting into the core layer (6). As a result of this cold forming, the collar (30) has a higher rigidity than the area of the surface layer (4, 5) surrounding it. The invention also provides a method for permanently and securely fastening components at any point on the surface layer of panels forming the wall or ceiling elements of the structure using blind rivets.