Motor Vehicle Subframe with Diagonal Strut Cross-Brace
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Solution Overview
Problem
Existing motor vehicle subframes face challenges in achieving high rigidity while minimizing weight, particularly at link connection points, which affects both crash deformation and driving dynamics.
Innovation Solution
A subframe design featuring longitudinal members connected via a cross brace with diagonal struts that intersect at the front and rear link connections, providing enhanced transverse rigidity using slim and lightweight materials, and additional strut cross elements that improve power flow and reduce stress peaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a large, flat stiffening element is used to increase rigidity at link connection points, then the rigidity is improved, but the weight increases significantly
Solution Approach 1:
The stiffening function is segmented from a single large flat element into multiple diagonal struts arranged in a truss-like pattern. These struts are distributed across the subframe structure, with each strut providing localized stiffening while collectively achieving overall rigidity enhancement at link connection points without requiring a large continuous stiffening element.
Solution Approach 2:
The invention transitions from a two-dimensional flat stiffening element to a three-dimensional truss-like structure with diagonal struts. This spatial arrangement creates additional load paths and structural efficiency, achieving comparable or superior rigidity with less material by utilizing the third dimension for structural optimization.
2Strength
If more material is used to increase subframe rigidity, then the strength is improved, but the weight increases
Solution Approach 1:
The subframe employs a composite structural approach combining longitudinal members, cross members, and diagonal struts into an integrated truss-like system. This composite structure achieves superior rigidity-to-weight ratio by distributing loads across multiple structural elements rather than relying on a single heavy component.
Solution Approach 2:
The invention optimizes structural parameters by changing the arrangement and configuration of structural elements. The diagonal struts are positioned at specific angles and locations to maximize structural efficiency, transforming the subframe from a conventional design to a optimized truss-like structure that reduces material usage while maintaining or improving rigidity.
3Stability of the object's composition
If a truss-like structure with diagonal struts is used to improve transverse rigidity, then the rigidity is significantly improved, but the structural complexity increases
Solution Approach 1:
The diagonal struts serve multiple functions simultaneously: they provide transverse stiffening, create additional load paths for force distribution, and contribute to overall structural integrity. This multi-functionality reduces the need for separate dedicated stiffening elements, simplifying the overall design despite the truss-like configuration.
Solution Approach 2:
The stiffening function is merged into the primary structural members rather than being added as separate auxiliary components. The diagonal struts are integrated with the longitudinal members and cross members to form a unified truss-like structure, eliminating the need for additional flat stiffening elements and reducing overall structural complexity.
Data Source
Figure 1
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AI summary
The frame has left and right longitudinal chassis beams (2, 3) running in a driving direction and connected with one another by a bracing cross-tie (10). Crossing diagonal rods (11,12) of the cross-tie are connected with the beams in a driving direction viewed at a height of front steering joints (9) and connected with the beams in the direction behind the rear steering joints. The diagonal rods are designed as hollow profile, where the rods and the beams comprise a common fastening point.