Vehicle Roof Brazing Edge Stability via Negative Curved Surface
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Solution Overview
Problem
Conventional vehicle roof structures experience instability and waviness at the edges of solidified brazing material due to non-linear edge formation, making it difficult to achieve clean edges during the joining of roof panels and side outer panels.
Innovation Solution
A vehicle roof structure design featuring a closely facing section, a negative curved-surface section with a recessed face, and a mounting surface on the side outer panel, where the brazing material is preheated using a laser beam to ensure smooth connection and suppress wave formation at the edges, with the brazing material's edge positioned on the negative curved-surface section to maintain stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If brazing material is used to join roof panel and side outer panels, then the panels are connected, but waves occur at the edges of the solidified brazing material making the edges unstable and non-linear
Solution Approach 1:
The invention introduces a negative curved surface (recessed face) with arc-shaped geometry at the bonding surface of the roof panel. This curved surface guides the brazing material to form a smooth arc-shaped edge that matches the curvature, eliminating waves and achieving linear/clean edges after solidification. The curved guide surface transforms the unstable linear edge into a controlled curved edge.
Solution Approach 2:
The roof panel is pre-formed with a negative curved surface (recessed face) before the brazing process. This preliminary geometric preparation creates a mold that guides the brazing material during solidification, ensuring the edge forms the desired smooth curve without waves, rather than attempting to correct edge formation after brazing.
2Stability of the object's composition
If the edge of brazing material is positioned on a curved surface protruding upwards, then the edge is supported, but waves still occur and edges remain unstable
Solution Approach 1:
Instead of using a convex curved surface (protruding upwards) to support the brazing material edge as in conventional designs, the invention inverts the approach by using a concave negative curved surface (recessed face). This inverted geometry provides better support and guidance for the brazing material, preventing wave formation and achieving stable, smooth edges.
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
The solution effectively suppresses wave formation at the edges of the solidified brazing material, ensuring a stable and smooth connection between the roof panel and side outer panels, resulting in a more refined and stable vehicle roof structure.
Implementation Method 1
preheating a part of the negative curved-surface section by irradiating a laser beam (e.g., the laser beam 521 described later) onto at least the part of the negative curved-surface section
Implementation Method 2
a brazing material (e.g., the brazing material 40 described later), the vehicle roof structure including: a closely facing section (e.g., the closely facing section 11 described later) that is positioned at both side parts in a vehicle width direction of the roof panel
Data Source
AI summary
The vehicle roof structure includes: a closely facing section that abuts or is adjacent to a side outer panel; a negative curved-surface section that is positioned more inwards in the vehicle width direction than the closely facing section of the roof panel, and has a recessed face that is indented downwards; and a mounting surface that is formed in the side outer panel at an inner side in the vehicle width direction to downwards of the vehicle towards, and at which the closely facing section abuts or is adjacent, in which an edge, on a side of the roof panel, of the brazing material that has solidified to join the roof panel and the side outer panel is positioned on the negative curved-surface section.