Vehicle Frame Member Rigidity Layout for Uniform Crash Compression

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Solution Overview

Problem

Existing frame members in vehicles do not efficiently absorb collision loads when the impact absorbing member deforms unexpectedly, leading to a deterioration in collision-load absorption capacity.

Innovation Solution

A frame member with a closed-cross section configuration, featuring varying bending rigidities in its components, ensures efficient transmission and absorption of collision loads by suppressing unexpected deformation of the impact absorbing member, allowing uniform compression.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the impact absorbing member is designed to deform to absorb collision load, then the collision load absorption function is improved, but the frame member may not efficiently transmit the collision load when the impact absorbing member deforms unexpectedly

Engineering Contradiction:
Improvecollision load transmission efficiencyVSAvoiddeformation control precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The lateral walls are designed with non-uniform thickness to create different bending rigidities in different portions. The first and third portions have larger bending rigidities than the second portion, creating a localized quality variation that prevents unexpected deformation while maintaining overall absorption function.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The bending rigidity parameter is varied along the length of the lateral walls by changing the thickness distribution. This parameter change allows the structure to maintain stability during controlled deformation while preventing unexpected deformation modes that would compromise load transmission.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the frame member structure is made more rigid to prevent unexpected deformation, then the collision load transmission is improved, but the uniform compression of the frame member during collision may be hindered

Engineering Contradiction:
Improveimpact absorbing member support stabilityVSAvoidframe member compression uniformity
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The lateral walls have different thicknesses in different portions, creating localized variations in bending rigidity. This allows the structure to be rigid where needed (first and third portions) to prevent unexpected deformation, while the second portion maintains appropriate flexibility for uniform compression during collision.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The lateral walls are segmented into three portions with different bending rigidities. This segmentation allows each portion to perform its specific function: the first and third portions provide lateral support stability, while the second portion allows for controlled compression deformation.

Inventive Principle:
Principle #1Segmentation

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

Enhances the collision-load absorption capacity by ensuring the frame member efficiently transmits and absorbs collision loads, preventing unexpected deformation and improving uniform compression.

Implementation Method 1

the crash box has repeated buckling deformation in an extension direction thereof, so that the above-described impact to be transmitted to a vehicle body is absorbed

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

when the collision load is applied to the vehicle-body front structure from the forward side, the impact absorbing member is compressed easily

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP4647323A1Frame member for vehicle and vehicle-body front structure
Publication Date: 2025.11.12 MAZDA MOTOR CORP
  • EP4647323A1 patent drawingFigure 1
  • EP4647323A1 patent drawingFigure 2
  • EP4647323A1 patent drawingFigure 3

AI summary

A frame member comprises a first vertical wall, a second vertical wall, a first lateral wall, a second lateral wall, a first inner wall arranged between the first and second vertical walls in a vehicle width direction and extending in a vertical direction, interconnecting the first and second lateral walls, and a second inner wall arranged between the second vertical wall and the first inner wall in the vehicle width direction and extending in the vertical direction, interconnecting the first and the second lateral walls. Each of the first and second lateral walls comprises a first portion interconnecting the first vertical wall and the first inner wall, a second portion interconnecting the first and second inner walls, and a third portion interconnecting the second vertical wall and the second inner wall. Each bending rigidity of the first portion and the third portion is larger than that of the second portion.