Vehicle Bumper Beam Offset Crash Strength via Tube-Expanding Joints

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Solution Overview

Problem

Existing bumper structures are not adequately designed to withstand high-speed offset crashes, as they primarily focus on front crash loads, leading to limitations in extending length or increasing thickness, which can result in increased weight and processing difficulties for aluminum and steel materials.

Innovation Solution

A vehicle structure with a bumper beam and reinforcement members arranged to overlap in the vehicle width direction, where the reinforcement members are joined to the bumper beam by press-fitting and tube-expanding, enhancing the structural strength against offset loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the bumper structure length in vehicle width direction is increased to improve offset load strength, then the strength against offset load is improved, but the bending length increases and bending curvature decreases making processing difficult

Engineering Contradiction:
Improvestrength against offset loadVSAvoidprocessing difficulty
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The bumper structure is divided into a main body portion and a reinforcement portion that can be manufactured separately and then joined together. This segmentation allows each part to be optimized independently - the main body can be processed with standard bending curvature while the reinforcement portion adds the necessary strength without requiring excessive length extension

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bumper structure combines different materials or structural configurations in the main body and reinforcement portions. This composite approach enables the structure to achieve high offset load strength through material properties and structural design rather than simply increasing length, thereby avoiding processing difficulties

Inventive Principle:
Principle #40Composite materials

2Strength

If the bumper beam thickness or size is increased to improve strength against offset load, then the strength is improved, but the overall weight of the bumper structure increases

Engineering Contradiction:
Improvestrength against offset loadVSAvoidoverall weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The reinforcement portion is strategically positioned at specific locations where offset loads are most critical, rather than uniformly increasing the bumper beam thickness throughout. This localized reinforcement approach achieves the necessary strength improvement only where needed, minimizing the addition of material and thus controlling the overall weight increase

Inventive Principle:
Principle #3Local quality

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

This configuration improves the strength of the vehicle structure against offset loads while maintaining a simple design, reducing weight and processing challenges, and enhancing joint strength through precise fitting and adhesive use.

Implementation Method 1

joining by press-fitting the second member into the first member and the third member by tube-expanding the insertion part of the second member into the first member and the third member

Methodology Applied
Scientific EffectTube-expanding: Plasticity

Data Source

PatentEP3741628B1Vehicle structure and method for manufacturing the same
Publication Date: 2023.04.26 KOBE STEEL LTD
  • EP3741628B1 patent drawingFigure 1~2
  • EP3741628B1 patent drawingFigure 3~4
  • EP3741628B1 patent drawingFigure 5~6

AI summary

A vehicle structure (90) includes a first member (1) that extends in a vehicle width direction, second members (2, 3) that extend in a front-back direction that are inserted in the front-back direction with respect to the first member (1), and third members (4, 5) that are arranged at end portions (la, 1b) of the first member (1) in the vehicle width direction and joined to the end portions (1a, 1b).