Vehicle Welded Joint Geometry for Unequal Wall Thicknesses

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Solution Overview

Problem

Existing welding technologies face challenges in achieving high weld penetration depth in automotive components with varying wall thicknesses without causing burn-through, particularly in the thicker parts, which affects the service life and load-bearing capability.

Innovation Solution

A motor vehicle component design featuring a chamfered joining surface on one component and a V-shaped gap configuration, allowing for optimized penetration during welding by shifting the weld root deeper into the joint, achieved through controlled plastic deformation without machining.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If welding is performed on components with different wall thicknesses to achieve high penetration depth in the thicker component, then the penetration depth improves, but burn-through occurs in the thinner component

Engineering Contradiction:
Improvepenetration depthVSAvoidweld quality
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies local quality by creating a chamfer specifically at the joining surface of the thicker component (first component). This localized geometric modification allows the weld to penetrate deeper into the thicker component without requiring increased welding parameters that would cause burn-through in the thinner component. The chamfer concentrates the welding energy where it is needed most - in the thicker component - while protecting the thinner component from excessive heat input.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If the joining surface is modified to improve weld penetration, then penetration depth increases, but additional machining processes are required

Engineering Contradiction:
Improvepenetration depthVSAvoidmanufacturing process
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The chamfer is created during the forming process itself, before the welding operation takes place. This preliminary action integrates the preparation of the joining surface into the existing manufacturing flow without requiring separate machining steps. The forming process that shapes the component walls also creates the appropriate chamfer geometry at the joining surface, thereby preparing the component for optimal weld penetration in advance.

Inventive Principle:
Principle #10Preliminary action

3Strength

If V-shaped gap configuration is used to optimize penetration, then load-bearing behavior improves, but manufacturing precision requirements increase

Engineering Contradiction:
Improveload-bearing behaviorVSAvoidjoining gap configuration
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent employs asymmetry by creating a V-shaped joining gap through the chamfer configuration on the thicker component. This asymmetric geometry - with the wider opening at the top and narrower base at the root - is specifically tailored to the welding process and the difference in wall thicknesses. The asymmetric V-shape allows for better weld pool control and more uniform heat distribution compared to a symmetric gap, thereby improving load-bearing behavior while remaining compatible with standard welding tolerances.

Inventive Principle:
Principle #4Asymmetry

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

The design ensures a reliable penetration depth of 2% to 10%, with potential for up to 50%, enhancing the service life and load-bearing stability of the welded joint without increasing weight.

Implementation Method 1

Welding is the permanent, material-bonded joining of components using heat and pressure

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 2

Penetration depth refers to the distance between the surface of the molten base material and the original surface of the base material, i.e., the depth of the molten zone in the base material

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP4656326A1Motor vehicle component
Publication Date: 2025.12.03 BENTELER AUTOMOBILTECHNIK GMBH
  • EP4656326A1 patent drawingFigure 1a)~1d)
  • EP4656326A1 patent drawingFigure 2a)~2b)
  • EP4656326A1 patent drawingFigure 3

AI summary

A motor vehicle component 2 comprises two steel parts 1, 11 with different wall thicknesses t1, t2, arranged at an angle α to each other and joined by a weld 18. A joining surface 13 at the end section 5 of the first part 1 has a chamfer 7 formed without machining. To form the chamfer 7, an end section 5 of a starting blank 3 is formed without machining. Subsequently, the end section 5 is trimmed and a butt surface 10 is created on the end face of the end section 5. The two parts 1, 11 are positioned relative to each other so that the joining surface 13 of the first part 1 and the joining surface 14 of the second part 11 face each other. The material-locking connection of the first part 1 and the second part 11 is achieved by a weld 18 at the joining surfaces 13, 14.