Vehicle Body Lower Structure Frame Member Arrangement
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Solution Overview
Problem
The existing vehicle body lower structure frame members are spaced too far from the center of the main body portion, leading to reduced axial crushing during collision loads, as they are both joined to the lower surface of the floor panel, which hinders effective deformation and energy absorption.
Innovation Solution
The frame members are arranged such that one is on the upper surface and the other on the lower surface of the floor panel, reducing the height difference between their centers and facilitating axial crushing by distributing collision loads more effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If both frame members are joined to the lower surface of the floor panel, then the structural configuration is simple, but the centers of cross sections are greatly spaced away from the center of the main body portion, causing bending deformation instead of axial crushing during collision
Solution Approach 1:
The patent applies dimensionality change by positioning frame members on both the upper and lower surfaces of the floor panel, transitioning from a single-plane (2D) configuration to a multi-plane (3D) arrangement. This spatial redistribution reduces the vertical distance between frame member centers and the main body portion center, enabling effective axial crushing while maintaining structural simplicity.
2Device complexity
If frame members are positioned far from the center of the main body portion, then the structural layout is simplified, but the moment inputted by collision load increases, reducing axial crushing effectiveness
Solution Approach 1:
By utilizing both upper and lower surfaces of the floor panel, the patent reduces the height difference (vertical distance) between the main body portion center and frame member centers. This dimensional optimization minimizes the moment arm, thereby reducing the moment inputted by collision load while keeping the frame member arrangement straightforward.
3Ease of manufacture
If both frame members are located on the lower surface of the floor panel, then the installation is simplified, but the height difference from the main body portion center is large, hindering axial crushing
Solution Approach 1:
The patent distributes frame members across both upper and lower surfaces of the floor panel, creating a more compact vertical configuration. This reduces the height difference from the main body portion center, enabling stable axial crushing deformation while maintaining installation simplicity through symmetric positioning.
Data Source
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AI summary
A vehicle body lower structure includes first and second frame members (7, 8) connected to front side members (4). Each first frame member (7) extends obliquely such that the first frame member (7) is located more outward in a vehicle width direction as extending toward a vehicle body rear side, and each second frame member (8) extends obliquely such that the second frame member (8) is located more inward in the vehicle width direction as extending toward the vehicle body rear side. One of the first and second frame members (7, 8) is provided on an upper surface of the floor panel (3) and the other one is provided on a lower surface of the floor panel (3).