Vehicle Frame Cross-Section Layout for Uniform Collision Buckling

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Solution Overview

Problem

Existing vehicle frame members are prone to uneven buckling during collisions, leading to non-uniform axial compression and inadequate absorption of collision loads due to asymmetrical flange projections and differing buckling resistances.

Innovation Solution

A vehicle frame member with a closed-cross section symmetrical about its center of gravity, featuring groove portions recessed inward and flanges protruding outward, ensuring uniform axial compression and increased buckling resistance by balancing flange projections and reducing asymmetrical buckling resistance differences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If flanges are offset toward the outward side in the vehicle width direction, then the resistance against buckling of the outer panel is higher than that of the inner panel, but the frame member cannot be axially-compressed uniformly and collision load cannot be absorbed expectedly

Engineering Contradiction:
Improvebuckling resistanceVSAvoiduniform axial compression
Core Design Contradiction:
StrengthVSStability of the object's composition

Solution Approach 1:

The patent applies asymmetry in reverse - it deliberately creates a symmetrical configuration about the center of gravity point to eliminate unwanted asymmetrical buckling behavior. The flanges are positioned such that their projection positions create point symmetry, ensuring that buckling resistance is balanced in all directions during axial compression, thereby resolving the uneven compression problem while maintaining high buckling resistance

Inventive Principle:
Principle #4Asymmetry

2Stability of the object's composition

If the closed-cross section is made symmetrical about the center of gravity point, then uniform axial compression and stable buckling resistance are achieved, but the complexity of positioning flanges and groove portions increases

Engineering Contradiction:
Improveuniform axial compressionVSAvoidflange and groove positioning
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent applies local quality by creating different functional zones within the cross-section: flanges are positioned at specific locations to provide attachment points and contribute to buckling resistance, while groove portions are strategically placed to reduce asymmetry. Each local feature is optimized for its specific function while collectively achieving overall point symmetry about the center of gravity

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4650252A1Frame member for vehicle
Publication Date: 2025.11.19 MAZDA MOTOR CORP
  • EP4650252A1 patent drawingFigure 1
  • EP4650252A1 patent drawingFigure 2
  • EP4650252A1 patent drawingFigure 3

AI summary

A frame member for a vehicle, comprises a frame body portion (20A) having an upper wall portion (20a), a lower wall portion (20b), and a pair of side wall portions (20c, 20d), which together define a closed-cross section (7a) perpendicular to a longitudinal extension direction thereof, the closed-cross section having plural vertexes, a pair of groove portions (25, 26) formed at the pair of side wall portions (20c, 20d), the groove portions (25, 26) being recessed toward an inside of the closed-cross section (7a), and plural flanges (20e, 20f) protruding outward from the closed-cross section (7a). The closed-cross section (7a), at least in a specified longitudinal range, is symmetrical about a point of center of gravity (Z) of the closed-cross section (7a), including projection positions of the plural flanges (20e, 20f) , and is nonsymmetrical about all straight lines which pass through the center of gravity (Z) of the closed-cross section (7a) and are perpendicular to the longitudinal direction.