Spin-Welded Aluminum Ground Assemblies for Cost Reduction
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Solution Overview
Problem
The increasing use of aluminum alloy components in vehicles requires new joining approaches for electrical ground assemblies, as traditional arc welding methods are costly and unsuitable for aluminum-based metals, necessitating a low-cost and effective method for aluminum-based electrical ground assemblies.
Innovation Solution
A friction-welded ground assembly is developed using an aluminum alloy substrate with a clearance hole, an aluminum alloy weld nut, and a grounding bolt, where a spin-welded joint is formed by solid-state diffusion, utilizing a conically-shaped or flat portion of the outer wall to create a strong mechanical connection suitable for vehicular applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional arc welding processes are used to fabricate electrical ground assemblies, then strong joints can be achieved, but the manufacturing cost increases significantly
Solution Approach 1:
The patent replaces the thermal arc welding process with a mechanical spin-welding process. The weld nut is rotated at high speed against the substrate, generating friction heat that softens the material, followed by axial pressing to forge a solid-state diffusion bond. This mechanical approach eliminates the need for expensive arc welding equipment and consumables while achieving comparable joint strength.
Solution Approach 2:
The invention changes the fundamental parameters of the joining process by transitioning from thermal welding (arc welding) to friction-based solid state diffusion bonding. The spin-welding process controls parameters such as rotational speed, axial pressure, and friction time to achieve metallurgical bonding without melting, thereby reducing manufacturing costs while maintaining joint integrity.
2Ease of manufacture
If arc welding methods are used for aluminum alloy components, then electrical ground assemblies can be fabricated, but the process becomes unsuitable and costly for aluminum-based metals
Solution Approach 1:
The patent replaces arc welding with spin-welding, which is specifically suited for aluminum alloys. The mechanical friction and solid-state diffusion process avoids the metallurgical complications of arc welding aluminum, such as oxide layer interference and heat-affected zone issues, thereby improving both manufacturability and joint reliability for aluminum-based vehicles.
Solution Approach 2:
The invention changes the joining parameters from thermal arc welding to friction-based solid state bonding, which is more suitable for aluminum alloys. The spin-welding process generates controlled friction heat and applies axial pressure to create reliable metallurgical bonds in aluminum materials without the drawbacks of traditional arc welding methods.
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 method provides a cost-effective and strong spin-welded joint capable of withstanding significant push-out loads, suitable for electrical ground assemblies in aluminum alloy sheet metal components, enhancing the durability and efficiency of vehicle electrical systems.
Implementation Method 1
a spin-welded joint formed by solid state diffusion
Implementation Method 2
A friction-welded ground assembly is provided that includes an aluminum alloy substrate with a clearance hole; an aluminum alloy weld nut comprising a bolt bore and an outer wall
Data Source
AI summary
A friction-welded ground assembly that includes an alloy substrate with a clearance hole; an aluminum alloy weld nut having a bolt bore and an outer wall; and a grounding bolt. The bore is located substantially within the clearance hole and a portion of the outer wall is joined to the substrate at a friction-welded attachment. Further, the bolt is threaded within the bore. In addition, a method for making a ground includes the steps: rotating an aluminum alloy weld nut having an outer wall at a predetermined speed; lowering the outer wall of the rotating nut into contact with an aluminum alloy substrate to generate a frictional force for a friction time; arresting the rotation of the nut; and applying an axial forging force to the outer wall and the substrate for a forging time.