Vehicle Roof Panel Flange Fixing to Side Rail
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Solution Overview
Problem
Conventional vehicle body structures face challenges in achieving both firm fixing of the roof panel to the roof side rail and improving design quality, as the step portion between the roof panel and the flange obstructs a clean design aesthetic.
Innovation Solution
A vehicle body structure featuring a roof panel with a flange section fixed to the lower surface of a closed cross-section roof side rail, using a combination of adhesive and fasteners for secure attachment, which enhances strength against tensile loads and eliminates the visual step portion, allowing for improved design aesthetics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the step portion is provided between the roof panel and flange to hide the welded portion, then the welded portion is less likely to be seen from outside, but the design quality of the vehicle body deteriorates due to the step portion
Solution Approach 1:
The invention extracts and eliminates the step portion from the conventional structure. By making the flange section extend along the lower surface of the closed cross section without creating a step portion, the welded portion becomes naturally hidden while maintaining smooth exterior surfaces, thus resolving the contradiction between hiding welds and preserving design quality
Solution Approach 2:
Instead of creating a step portion to hide the weld (conventional approach), the invention inverts the approach by making the flange section extend underneath the closed cross section. This inversion allows the weld to be hidden without creating any protruding step portions, thereby maintaining design quality
2Strength
If the flange section is fixed to the lower surface of the closed cross section, then the strength against tensile load increases, but the structure complexity increases due to adhesive and fastener combination
Solution Approach 1:
The invention segments the fixing function into two distinct components: adhesive for bonding and fasteners for mechanical attachment. This segmentation allows each component to contribute differently to the overall strength, with fasteners primarily bearing tensile loads and adhesive providing bonding and sealing, thus achieving high strength while maintaining reasonable structural complexity
Solution Approach 2:
The invention uses a composite fixing system combining adhesive (chemical bonding) and fasteners (mechanical bonding). This composite approach leverages the strengths of both bonding methods to achieve superior tensile load resistance compared to either method alone, while the integration of these components remains manageable through proper design
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 configuration provides robust fixation of the roof panel to the roof side rail, increasing strength against both tensile and shearing loads while enhancing the vehicle's design quality by eliminating the step portion, thus improving both structural integrity and aesthetic appeal.
Implementation Method 1
the flange section adheres to the lower surface of the closed cross section by an adhesive
Data Source
Figure 1
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Figure 4
AI summary
To provide a vehicle body structure capable of simultaneously achieve firm fixing between a roof panel and a roof side rail and improvement in design quality of a vehicle body the vehicle body structure includes: a pair of roof side rails 3, each of which constitutes at least one each of closed cross sections 11a, 12a and extends in a vehicle longitudinal direction; and a roof panel 5 that is stretched between the pair of roof side rails 3 and extends in a vehicle width direction. The roof panel 5 has: a body section 5a that extends in the vehicle width direction; and a flange section 5b that is provided to both end portions in the vehicle width direction of the body section 5a and extends in the vehicle width direction along a lower surface of the closed cross section 12a. The flange section 5b is fixed to a lower surface 12f of the closed cross section 12a.