Automotive Exterior Panel Frame With Nested Struts for Impact Absorption
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Solution Overview
Problem
The existing door structure for automobiles faces challenges in effectively absorbing impact loads while maintaining panel stiffness without increasing weight, as the single strut provided for stiffness improvement limits impact absorption, and strong guard bars required for impact absorption lead to weight increments. Additionally, the manufacturing process becomes complex due to the need for thickness-reduced portions, which can compromise strength and increase manufacturing time.
Innovation Solution
A frame structure for automotive exterior panels featuring intersecting members with a groove part in one member and a uniform thickness in the other, allowing for simplified manufacturing and reliable impact load absorption, where the groove part is formed by providing an opening in the sheet material before bending, reducing the complexity of the intersection process and maintaining strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single strut is provided for panel stiffness improvement, then panel stiffness is improved, but impact absorption capability is insufficient
Solution Approach 1:
The single strut is segmented into multiple struts (first struts and second struts) arranged in different directions. This segmentation allows the structure to maintain panel stiffness while distributing impact loads across multiple members, thereby improving impact absorption capability without compromising structural rigidity.
Solution Approach 2:
One strut is nested within another at the intersection portion. Specifically, one of the first struts passes through a groove part formed in the second strut, creating a nested configuration. This nesting allows the struts to intersect while maintaining their individual structural integrity and load-bearing capabilities.
2Reliability
If a strong guard bar is provided for impact absorption, then impact absorption capability is improved, but weight increases
Solution Approach 1:
The impact absorption function is segmented across multiple struts rather than concentrated in a single heavy guard bar. By distributing the impact load to multiple members extending in different directions, the structure achieves effective impact absorption with lighter individual components, thereby reducing overall weight.
Solution Approach 2:
The struts are arranged in different spatial directions (first direction and second direction perpendicular to each other). This multi-dimensional arrangement allows the structure to absorb impacts from various directions simultaneously, replacing the need for an overly robust single-direction guard bar and reducing weight.
3Device complexity
If thickness-reduced portions are provided to enable member intersection, then members can intersect in limited space, but manufacturing process becomes complicated and member strength decreases
Solution Approach 1:
Instead of reducing thickness, one strut is nested within another at the intersection. The groove part in the second strut accommodates the first strut, allowing intersection while maintaining uniform thickness throughout both members. This eliminates the need for complex thickness-reduction processing and associated press forming operations.
Solution Approach 2:
The groove part is extracted from the second strut by providing an opening in the sheet material before bending. This extraction creates space for the first strut without requiring thickness reduction, simplifying the manufacturing process while enabling member intersection.
4Device complexity
If thickness-reduced portions are provided to enable member intersection, then members can intersect in limited space, but manufacturing time increases
Solution Approach 1:
The opening for the groove part is provided in the sheet material before bending to form the struts. This preliminary action allows the groove part to be created during the forming process itself, rather than requiring subsequent thickness-reduction operations, thereby reducing manufacturing time.
Solution Approach 2:
The nesting configuration eliminates the need for time-consuming thickness-reduction processing. By simply forming the groove part through the opening and bending process, the struts can intersect while maintaining uniform thickness, significantly reducing manufacturing time compared to traditional thickness-reduction methods.
5Device complexity
If thickness-reduced portions are provided, then members can intersect with each other, but member strength decreases at the thickness-reduced position
Solution Approach 1:
One strut is nested within another at the intersection portion, with one strut passing through a groove part in the other. This nesting allows the struts to intersect while maintaining their full thickness and structural strength. The groove part provides clearance for intersection without compromising the load-bearing capacity of either strut.
Solution Approach 2:
The groove part is extracted by providing an opening in the sheet material before bending. This extraction creates the necessary space for intersection while maintaining uniform thickness throughout the strut, preventing strength reduction at the intersection location.
Data Source
AI summary
A frame structure of an automotive exterior panel includes a sheet-like outer panel, a plurality of first members, each of which has an elongated shape, and which are disposed on a vehicle inside with respect to the outer panel, and a second member that has an elongated shape and intersects with the plurality of first members, in which each of the plurality of first members extends in a first direction along a sheet surface of the outer panel, and has a groove part recessed from the vehicle outside toward the vehicle inside at a portion thereof in a longitudinal direction, the second member extends in a second direction along the sheet surface of the outer panel, and has a thickness in a vehicle inside-outside direction, which is uniform at a portion closer to the center than at both end portions in the longitudinal direction, and at an intersection portion where each of the plurality of first members and the second members intersect with each other, the second member is in contact with the inside of the groove part provided in each of the plurality of first members.