Differential Carrier Ring Gear Venting for Crack-Resistant Welding
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Solution Overview
Problem
Differential carrier and ring gear assemblies in vehicles are prone to cracks due to heavy stress conditions, including centrifugal stress, vibrations, and temperature changes, which lead to reduced fatigue performance and increased cracking.
Innovation Solution
A laser welded differential carrier and ring gear assembly design featuring a slot on the contact faces that forms a vent hole, allowing residual gases to dissipate to the atmosphere during welding, thereby reducing stress concentration and crack formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If laser welding is performed on differential carrier and ring gear assemblies, then strong welds are achieved, but cracks form due to stress concentration from trapped gases
Solution Approach 1:
The patent extracts harmful gases from the welding zone by creating a vent hole through a slot in the contact face. The slot allows trapped gases to escape during laser welding, preventing gas pockets that would cause stress concentration and cracks in the weld, thereby improving crack resistance while maintaining weld strength.
Solution Approach 2:
The patent converts the harmful effect of trapped gases (which cause stress concentration and cracks) into a beneficial outcome by designing a slot that intentionally allows controlled gas escape. The vent hole created by the slot transforms the potential harm of gas trapping into a beneficial venting mechanism that prevents weld defects.
2Ease of manufacture
If traditional welding methods are used, then assembly is achieved, but fatigue performance is reduced due to stress concentration
Solution Approach 1:
The patent removes the source of stress concentration by extracting trapped gases through the vent hole created by the slot. This prevents the formation of gas pockets that would create stress concentration points, thereby extending the fatigue life of the welded assembly while maintaining manufacturing feasibility.
Solution Approach 2:
The patent transforms the potential harm of gas trapping (which reduces fatigue life) into a beneficial venting system. The slot and resulting vent hole convert harmful trapped gases into a controlled escape path, eliminating stress concentration and improving fatigue performance.
3Ease of manufacture
If contact faces are welded without ventilation, then weld formation is achieved, but residual gases cause stress concentration and cracking
Solution Approach 1:
The patent extracts residual gases from the welding interface by creating a vent hole through the slot in the contact face. This allows gases to escape during weld formation, preventing the stress concentration and cracking that would otherwise occur from trapped gases, while maintaining ease of weld formation.
Solution Approach 2:
The patent converts the harmful effect of residual gases (which cause stress concentration and cracking) into a beneficial venting mechanism. The slot creates a controlled path for gas escape, transforming the potential harm of trapped gases into a beneficial feature that prevents weld defects.
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 enhances fatigue performance by reducing cracking and improving the quality of welds through ventilation of gases during the welding process, leading to a more durable assembly.
Implementation Method 1
directing a laser beam onto an external surface of the differential carrier effective to form a weld nugget disposed between the first and second contact faces
Implementation Method 2
laser welded differential carrier and ring gear assembly
Implementation Method 3
allowing residual gases to dissipate to the atmosphere during welding, thereby reducing stress concentration and crack formation
Data Source
AI summary
A differential carrier and ring gear assembly for a vehicle is provided. The assembly comprises a differential carrier, a ring gear, and a weld nugget. The differential carrier comprises an outer surface including a first contact face having a weld end extending to a root end. The first contact face has a first slot formed on a first radial portion thereof. The ring gear is disposed about the differential carrier and comprises an inner side having an inner surface. The inner side has a stop flange abutting the root end. The inner surface comprises a second contact face disposed on the first contact face such that the root end is in abutment with the second end. The first and second hollow channels define a pocket therebetween and the first slot defines a first vent hole for venting. The weld nugget is disposed between the first and second contact faces.