Axle Housing Spindle Weld Structure for Fatigue Crack Resistance

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Solution Overview

Problem

Existing axle housing assemblies face issues with fatigue cracks and reduced strength due to stress concentrations caused by external curls and swage marks during friction welding, which can lead to premature failure under load.

Innovation Solution

The axle housing assembly incorporates a friction weld joined by an extension weld that encircles the arm portion, removing external curls and filling the resulting recess to eliminate stress concentrations and enhance structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If friction welding is used to join the spindle to the arm portion, then manufacturing efficiency is improved, but external curls and swage marks are generated causing stress concentrations that reduce fatigue strength

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidfatigue strength
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The harmful external curls are removed through machining operations after friction welding, extracting the defective material that causes stress concentrations and fatigue failures while preserving the beneficial friction weld joint

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

An extension weld is added after curl removal to pre-reinforce the area before service loads are applied, preventing future fatigue crack initiation at the weld zone where stress concentrations would otherwise occur

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If the arm portion is designed to accommodate friction welding, then ease of manufacture is improved, but stress concentrations at the weld zone reduce the load-bearing capacity

Engineering Contradiction:
Improveease of manufactureVSAvoidload-bearing capacity
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The extension weld is applied locally at the specific position where stress concentrations occur due to friction welding, providing targeted reinforcement without requiring redesign of the entire arm portion or use of heavier materials

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The arm portion becomes a composite structure combining the base metal, friction weld zone, and extension weld overlay, where each layer serves a specific function and the combined structure achieves superior strength-to-weight ratio

Inventive Principle:
Principle #40Composite materials

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 solution improves fatigue performance and durability, allowing the axle housing assembly to withstand higher loads without redesigning the assembly or using heavier materials, thus extending its expected life and maintaining performance even at low manufacturing volumes.

Implementation Method 1

The friction weld may extend around the axis and may join the spindle to the arm portion

Methodology Applied
Scientific EffectFriction welding: Friction Welding

Data Source

PatentEP4039498B1Axle housing assembly having a spindle and method of manufacture
Publication Date: 2024.01.03 ARVINMERITOR TECHNOLOGY LLC
  • EP4039498B1 patent drawingFigure 1
  • EP4039498B1 patent drawingFigure 2
  • EP4039498B1 patent drawingFigure 3

AI summary

An axle housing assembly and a method of manufacture. A friction weld may join a spindle to an arm portion of the axle housing assembly. An extension weld may encircle the arm portion. The extension weld may extend from the friction weld in a direction that may extend away from the spindle.