Punched Intermediate Sheet Assembly for Stiff Automotive Bonding
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Solution Overview
Problem
Current motor vehicle structures require significant amounts of glue for stiffness and stress distribution, making conventional solutions uneconomical, and existing high-temperature brazing methods are not suitable for automotive applications.
Innovation Solution
An assembly of sheets with an intermediate sheet having punchings that allows a single bead of glue to spread between the sheets, combined with electrical resistance welding points for metallurgical connections, optimizing glue usage and stiffness without additional costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a significant amount of glue is used to ensure sufficient stiffness of sheet metal joints, then the stiffness is improved, but the cost increases making conventional solutions uneconomical
Solution Approach 1:
The intermediate sheet is segmented with multiple punchings (holes) distributed across its surface. These punchings create localized bonding zones where glue is concentrated, rather than requiring a continuous layer of glue across the entire sheet. This segmentation allows the glue to be distributed efficiently at specific critical points, reducing the total amount of glue needed while maintaining joint stiffness.
Solution Approach 2:
The punchings create zones of localized bonding strength on the intermediate sheet. By concentrating glue at these specific localized positions rather than distributing it uniformly, the solution achieves sufficient stiffness at critical joint locations while minimizing the overall glue quantity required, thereby reducing cost.
2Strength
If high-temperature brazing is used to assemble structural panels, then the fixation strength is improved, but the manufacturing process becomes complicated and unsuitable for automotive applications
Solution Approach 1:
The invention changes the temperature parameter from high-temperature brazing (up to 620°C) to moderate-cure-temperature adhesive bonding. This parameter change maintains sufficient fixation strength while dramatically simplifying the manufacturing process, making it suitable for automotive production environments that cannot accommodate extreme temperatures.
Solution Approach 2:
The invention substitutes the thermal-brazing process with a mechanical-adhesive bonding process. Instead of using heat and molten filler metal (brazing), the solution uses adhesive materials that cure at lower temperatures to create strong bonds between panels, thereby eliminating the need for complex high-temperature equipment and processes.
3Strength
If multiple sheets are stacked to ensure rigid areas for shock absorption and stress distribution, then the structural performance is improved, but the assembly complexity and cost increase
Solution Approach 1:
The intermediate sheet with punchings serves multiple functions simultaneously: it provides structural reinforcement, creates localized bonding zones for adhesive attachment, and facilitates stress distribution across the multi-sheet assembly. This multi-functionality reduces the need for additional separate components, simplifying the overall assembly structure while maintaining stress distribution capabilities.
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 reduces glue quantity, enhances stiffness by 45% compared to conventional methods, and achieves weight savings through punching, while maintaining economic and quick assembly processes.
Implementation Method 1
the intermediate sheet comprises punchings crossed by the glue extending between said intermediate sheet and the second sheet
Implementation Method 2
at least one electrical resistance welding point providing a metallurgical connection between the intermediate sheet and each of the first and second sheets
Data Source
Figure 1~3
Figure 4
AI summary
The present invention relates to an assembly of sheets (2), particularly for a motor vehicle, comprising: - a first sheet (6); - a second sheet (8) superimposed on the first sheet; - an intermediate sheet (7) disposed between the first sheet and the second sheet; - glue (4) between the first sheet and the intermediate sheet; remarkable in that the intermediate sheet includes punchings (7.1) through which the glue extends between said intermediate sheet and the second sheet, so as to ensure with said glue a bond between said intermediate sheet and each of said first and second sheets.