Motor Vehicle Door Edge Joining Gap Minimization
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Solution Overview
Problem
Existing methods for producing motor vehicle add-on parts result in sharp-edged sheet metal protrusions and imperfect edge finishes due to free sheet metal edges, compromising the quality of the material-to-material connection seam.
Innovation Solution
The method employs at least partially elastic sheet metal deformation to press the fold of one sheet metal part against the outer edge of the other, using a spring-loaded pressure roller to minimize joint gaps and ensure a clean edge finish, with pocket-shaped recesses providing local compensation for excess material, and forming a continuous laser-welded or soldered seam on multiple sides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the inner panel is pushed against the fold of the outer panel to close the joining gap, then the joint gap is minimized, but sharp-edged sheet metal protrusions are created on the non-visible side
Solution Approach 1:
The outer panel is divided into multiple sections along its circumference, with each section having an independently formable fold. This segmentation allows each fold to be separately deformed and pressed against the inner panel, enabling precise control over the edge finish at each location while maintaining joint gap closure throughout the entire perimeter.
Solution Approach 2:
The fold of the outer panel is elastically deformed by applying compressive force, changing its geometric parameters from a straight edge to a bent configuration. This elastic deformation allows the fold to conform to the inner panel's outer edge, eliminating sharp protrusions while maintaining the closed joint gap. The elastic nature of the deformation enables the material to flex without permanent damage.
2Strength
If sheet metal parts are welded or soldered to create a material-locking seam, then structural integrity is improved, but the process complexity and time increase
Solution Approach 1:
The welding or soldering process is performed continuously along the entire circumference of the add-on part, creating an unbroken material-locking seam. This continuous operation eliminates the need for repeated positioning and starting/stopping at discrete locations, significantly improving productivity while maintaining consistent structural integrity throughout the joint.
Solution Approach 2:
The folding and joining operations are merged into a single integrated process. The fold is formed and pressed against the inner panel simultaneously with the welding or soldering operation, eliminating separate steps for folding, positioning, and joining. This consolidation reduces process complexity and increases overall efficiency.
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 achieves a peripherally perfect edge finish without protruding sheet metal, ensuring a high-quality, cohesive material-locking seam with tolerance compensation and improved structural integrity.
Implementation Method 1
at least partially elastic sheet metal deformation, by which the fold of one sheet metal part is pressed against the outer edge of the other sheet metal part
Implementation Method 2
the sheet metal parts are welded or soldered to one another at their now abutting edges by a synchronously carried laser beam
Implementation Method 3
the sheet metal parts are welded or soldered to one another
Data Source
Figure 1~2
AI summary
Production of a vehicle door with an inner metal sheet and an outer metal sheet comprises prefabricating one of the metal sheet parts on the outer edge with pocket-like recesses and pressing the fold of the metal sheet during joining to minimize the joining gap up to solidification of the interlocking connection by sheet metal deformation on the outer edge of the other metal sheet part.