Sheet Metal Assembly Using Deep-Drawn Embossing Elements
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Solution Overview
Problem
Existing methods for connecting sheet metal parts, such as aluminum and steel, are complex and costly due to the need for expensive steel stamping elements with intricate geometries, and they often require precise orientation and additional coatings, which can compromise corrosion resistance and surface finish.
Innovation Solution
A method involving a deep-drawing process to embed a simple, rotationally symmetrical embossing element into the aluminum sheet metal part, followed by spot welding with a steel component, allowing for a non-destructive, flush connection that eliminates the need for coatings and enhances corrosion protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a steel stamping element with complex geometry (conically tapering tip, flared rivet head) is used to connect aluminum and steel sheet metal parts, then the connection strength is improved, but the manufacturing cost increases significantly
Solution Approach 1:
The patent replaces expensive, complex steel stamping elements with simple, inexpensive steel pins or rivets that can be mass-produced. These simplified fasteners achieve adequate connection strength through the deep-drawing process and spot welding, eliminating the need for costly complex geometries while maintaining functional performance.
Solution Approach 2:
The patent extracts and eliminates the complex geometric features (conically tapering tip, flared rivet head) from the stamping element design, retaining only the essential functional components (pin body, head). This simplification reduces manufacturing complexity and cost while the deep-drawing and welding processes provide the necessary connection strength.
2Strength
If a steel stamping element with complex geometry is used, then connection strength is improved, but the device complexity and orientation requirements increase
Solution Approach 1:
The patent employs asymmetric spot welding parameters (different welding currents, times, or electrode forces for the aluminum and steel sides) to compensate for the simplified symmetric geometry of the steel pin. This ensures adequate connection strength without requiring complex asymmetric fastener geometries or strict orientation control during assembly.
3Reliability
If additional coatings are applied to the stamping element, then corrosion resistance is improved, but the surface finish and appearance are compromised
Solution Approach 1:
The patent converts the potential harm of direct metal-to-metal contact between dissimilar metals (aluminum and steel) into a benefit by using the deep-drawing process to create an aluminum deformation zone around the steel pin. This aluminum zone acts as a sacrificial anode and physical barrier, providing both corrosion protection and a flush surface finish without requiring additional coatings.
Solution Approach 2:
The patent creates a composite connection structure consisting of three zones: the steel pin core, the aluminum deformation zone (formed by deep-drawing), and the spot weld nugget. This composite structure provides inherent corrosion resistance through galvanic protection and surface flushness, eliminating the need for additional protective coatings that would compromise appearance.
4Reliability
If a deep-drawing process is used to embed the embossing element, then the connection becomes non-destructive and flush, but the process complexity increases
Solution Approach 1:
The patent merges the embossing element embedding process with the existing spot welding operation by positioning the simple steel pin in the aluminum sheet before welding. The pin serves dual purposes: as the embossing element for material displacement and as the welding electrode/substrate for creating the connection. This integration eliminates separate embedding and welding steps, reducing overall process complexity while achieving non-destructive, flush connections.
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 method simplifies the connection process, reduces production costs, and ensures strong, corrosion-resistant, flush connections suitable for automotive applications, with the embossing element being completely surrounded by the joining material for improved protection.
Implementation Method 1
the embossing element is pressed into the material of the first sheet metal part in a deep-drawing direction... with simultaneous plastic deformation of the embossing element, as a result of which a positive connection is formed between the embossing element and the sheet aluminum part
Implementation Method 2
the end 7 of the embossing element 3 protruding from the aluminum sheet part 1 is welded to the sheet steel part 5... in subsequent resistance spot welding
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to a method for connecting at least two sheet metal parts (1, 5), wherein an impressing element is fastened to the first sheet metal part (1) and then the impressing element (3) fastened to the first sheet metal part (1) is welded to the second sheet metal part (5), in particular by spot welding. According to the invention, in order to fasten the impressing element to the first sheet metal part (1), the impressing element (3) is pressed into the material of the first sheet metal part (1) in a deep-drawing direction (T) in a deep-drawing process and enters into a form-locked connection to the first sheet metal part (1) under plastic deformation.