Sheet Steel Chassis Shell Structure for Flange Springback Control
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Solution Overview
Problem
Chassis components, particularly wishbones and subframes, face challenges in achieving high dimensional accuracy and structural strength while minimizing weight, due to the pronounced cracking behavior of high-strength sheet steel, which affects the formation of angled edges and subsequent welding processes.
Innovation Solution
The use of carbon steel or press-hardenable steel with stepped embossings on the web edges of sheet metal shells, where the embossing length is significantly longer than the sheet thickness, helps counteract snapping behavior and ensures precise angle formation between the web and flanges, allowing for butt-welding of sheet metal shells to enhance dimensional accuracy and rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If high-strength sheet steel is used to reduce component weight, then weight is reduced, but dimensional accuracy deteriorates due to pronounced springback behavior
Solution Approach 1:
The patent applies preliminary action by forming counteracting embossments on the web of the sheet metal shell before the final forming process. These embossments create pre-stressed regions that compensate for the springback effect during subsequent forming operations, ensuring the flanges achieve the precise 90-degree angle required for accurate butt-welding while maintaining the weight benefits of high-strength steel
2Manufacturing precision
If flanges are formed at 90 degrees to the web for butt-welding, then manufacturing accuracy is improved, but springback behavior worsens causing dimensional deviations
Solution Approach 1:
The patent applies preliminary anti-action by creating embossments that generate pre-stresses opposing the springback forces. These embossments are strategically positioned on the web to counteract the elastic recovery that occurs when flanges are formed at 90 degrees, thereby maintaining dimensional accuracy while enabling the butt-welding configuration
3Ease of manufacture
If shell sections are joined by overlap joint, then manufacturing ease is improved, but structural rigidity deteriorates compared to butt-welding
Solution Approach 1:
The patent inverts the conventional joining approach by using butt-welding instead of overlap joints. This requires the flanges to be precisely formed at 90 degrees to the web, which is achieved through the embossment technology. The inversion enables direct structural connection that significantly improves rigidity and load-bearing capacity while maintaining manufacturability through the preliminary embossing process
Data Source
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AI summary
The invention relates to a component (1) for a motor vehicle, in particular as a chassis component, with at least one one-piece sheet metal shell (1.1) formed from formed sheet steel, which has a web (1.11) and lateral flanges (1.12, 1.13) angled relative to the web, wherein the angle (a) defined by the web (1.11) and the flange (1.12, 1.13) is essentially in the range of 85° to 95°, wherein the length of the flange is a multiple of its maximum height, and wherein the web (1.11) has a web edge (1.14, 1.15) in the region of the flange (1.12, 1.13). To improve such a component with regard to the spring-up behavior of its flanges (1.12, 1.13) which are angled by forming, the invention provides that the web (1.11) has a step-shaped indentation (1.16, 1.17) extending along the flange (1.12, 1.13) on at least one of the web edges (1.14, 1.15), the indentation of which extends along the flange (1.12, 1.13).13) measured length or arc length is at least 10 times the average sheet thickness (D) of the sheet shell and/or at least 30% of the length or arc length of the flange (1.12, 1.13).