Twist Beam Axle Weld Geometry for Deeper Joint Penetration

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Solution Overview

Problem

Existing composite steering axes face challenges in stress behavior and lifespan due to high dynamic and static forces, particularly longitudinal forces, which lead to high loads on weld seams between the torsion profile and side arms, affecting the strength and quality of the weld.

Innovation Solution

A composite steering axis design featuring a torsion profile with a sloped end section and a V-shaped configuration in the weld gap, allowing for a deeper and more stable weld seam incorporation, thereby enhancing the structural integrity and lifespan without increasing weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional weld seams are used between the torsion profile and side arms, then the manufacturing process is simple, but the weld seam strength and service life are insufficient due to high dynamic and static forces

Engineering Contradiction:
Improveweld seam strengthVSAvoidjoining surface complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The joining surface of the torsion profile is prepared in advance with a bevel shape before welding. This preliminary geometric preparation creates a V-shaped joint gap that enables deeper weld penetration and stronger weld seams, directly addressing the reliability issue without adding complex welding processes

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The geometry of the joining surface is changed from a conventional flat surface to a beveled surface with specific angular parameters. This parameter change in the joining surface geometry transforms the joint gap configuration, enabling improved weld penetration depth and strength under high dynamic and static forces

Inventive Principle:
Principle #35Parameter changes

2Strength

If the penetration depth of the weld seam is increased to improve joint strength, then the weld seam strength increases, but the risk of burn-through on thinner side arms increases

Engineering Contradiction:
Improvejoint strengthVSAvoidburn-through risk
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The bevel is applied specifically to the joining surface of the torsion profile where higher strength is needed, while the side arms maintain their original geometry. This localized geometric modification creates a V-shaped joint gap that distributes the welding heat more evenly, enabling deep penetration into the torsion profile without causing burn-through on the thinner side arms

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The V-shaped joint gap is created in advance through beveling the torsion profile joining surface. This preliminary geometric preparation controls the weld metal flow and heat distribution during welding, allowing deep penetration while preventing burn-through on the side arms by guiding the weld pool into the beveled geometry

Inventive Principle:
Principle #10Preliminary action

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 achieves a higher service life for the composite steering axis with improved static and dynamic stress behavior, maintaining driving performance and stability while reducing the risk of weld failure.

Implementation Method 1

The torsion profile is connected to each side arm by a weld

Methodology Applied
Scientific EffectWelding: Welding

Implementation Method 2

Penetration is the depth of the molten zone in the base material, in this case the steel material of the torsion profile in the end section

Methodology Applied
Scientific EffectMelting: Melting

Data Source

PatentEP4541610A1Twist beam axle
Publication Date: 2025.04.23 BENTELER AUTOMOBILTECHNIK GMBH
  • EP4541610A1 patent drawingFigure 1a~1d
  • EP4541610A1 patent drawingFigure 2a~2b
  • EP4541610A1 patent drawingFigure 3

AI summary

The invention relates to a compound link axle comprising two side arms 11 and a torsion profile 1. The torsion profile 1 is connected to each side arm 11 by a weld 18. At least in the area of ​​the weld, the torsion profile 1 has a wall 4 with a wall thickness t1 that is greater than the wall thickness t2 of a wall 12 of a side arm 11. The torsion profile 1 has a joining surface 13 at each end section 5, and the side arms 11 each have a joining surface 14, wherein the torsion profile 1 and the side arms 11 are each connected at their mutually facing joining surfaces 13, 14 by a weld 18. The joining surface 13 at the end section 5 of the torsion profile 1 has a chamfer 9 produced without machining. The joining gap 15 formed between the mutually facing joining surfaces 13, 14 of end section 5 and side arm 11 is configured in a V-shape.This can significantly increase the penetration of the weld seam 18 on the torsion profile 1.