Automobile Front Pillar Stiffness via Composite Inner Panel
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Solution Overview
Problem
The challenge is to increase the stiffness of automobile front pillars while minimizing weight, particularly for curved designs that project outward, without compromising the visibility range from the passenger compartment.
Innovation Solution
A front pillar design featuring a hollow member with a curved shape, an outer panel, and an inner panel where the inner panel is positioned on the passenger compartment side to reinforce the hollow member, with specific flange configurations for welding and a nut system that reduces the pillar's size and weight, and incorporates a restricting concave section to prevent relative displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the wall thickness or diameter of the hollow member is increased to achieve equivalent stiffness for curved designs, then the stiffness is improved, but the weight increases
Solution Approach 1:
The front pillar uses a composite structure combining a hollow member with an inner panel and outer panel. The inner panel is formed to lie along the hollow member's wall section on the passenger compartment side, creating a composite structure that increases stiffness without requiring increased wall thickness or diameter of the hollow member alone, thus avoiding weight increase.
2Strength
If the diameter of the hollow member is increased to achieve equivalent stiffness, then the stiffness is improved, but the field of view from the passenger compartment narrows
Solution Approach 1:
The inner panel is formed to lie along the hollow member's wall section on the passenger compartment side, creating a composite structure that increases stiffness without requiring increased diameter of the hollow member. This maintains the field of view from the passenger compartment while achieving the required stiffness for curved designs.
3Ease of manufacture
If flanges are added to join outer panel and inner panel, then the joining capability is improved, but the size of the flange increases
Solution Approach 1:
The flange is divided into a first flange and a second flange. The first flange joins the outer panel to the hollow member, while the second flange joins the inner panel to the hollow member. This segmentation allows each flange to be optimized for its specific joining function, reducing the overall size needed compared to a single large flange.
Data Source
AI summary
A front pillar for an automobile includes an outer panel, an inner panel, and a hollow member disposed between the outer and inner panels. The outer panel has a roof-joining outer flange section projecting toward a roof skin flange section of a roof beyond the hollow member, and joined by spot welding to the roof skin flange section. A roof-joining extended flange section is joined by welding to at least two surfaces of the hollow member, extended to project toward the roof skin flange section beyond the hollow member and overlap the roof-joining outer flange section, and joined by spot welding to the roof skin flange section together with the roof-joining outer flange section.