Cooling Unit Joint Structure for Void-Controlled FSW Sealing
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Solution Overview
Problem
In liquid-cooling units for vehicle-mounted equipment, the joining of aluminum alloy components via friction stir welding often results in voids near stress concentration areas, leading to reduced joining strength and potential crack propagation due to size and shape variations between the jacket main body and sealing body.
Innovation Solution
A cooling unit design featuring a stepped portion on the unit main body and a corresponding flat plate sealing body, where a void is intentionally formed on the unit main body side of the plasticized region during friction stir welding, away from the stress concentration area, to prevent crack initiation and maintain mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If friction stir welding is used to join aluminum alloy components, then joining strength is improved, but voids form near stress concentration areas reducing reliability
Solution Approach 1:
The invention intentionally creates a void in a non-critical region (away from stress concentration areas) to serve as a stress relief zone. This converts the harmful effect of void formation during friction stir welding into a beneficial feature that prevents crack initiation and propagation at critical stress concentration points, thereby improving overall joint reliability while maintaining strong bonding.
Solution Approach 2:
The invention applies different structural characteristics to different regions of the joint. The sealing body has a stepped portion that creates a localized void region in areas of low stress concentration, while maintaining dense, void-free bonding in high-stress areas. This spatial variation in structural quality allows the joint to simultaneously achieve high strength and high reliability.
2Adaptability or versatility
If size and shape variations occur between jacket main body and sealing body, then manufacturing flexibility is improved, but void positioning becomes unpredictable reducing joining quality
Solution Approach 1:
The invention performs preliminary design of the sealing body with a predetermined stepped portion that is specifically configured to create a void in a non-critical region. This pre-planned void positioning strategy ensures that even with size and shape variations between components, the void will consistently form in a safe location away from stress concentration areas, maintaining joining quality despite manufacturing tolerances.
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 design secures the joining strength between the unit main body and sealing body, enhancing the reliability of the cooling unit by positioning the void away from stress concentration areas, thus preventing crack development and maintaining mechanical strength.
Implementation Method 1
Friction Stir Welding (FSW) is a method for solid-phase welding metal members to each other by moving a rotary tool along a butted portion of metal members while rotating the rotary tool, and by allowing the metal in the butted portion to plastically flow by frictional heat between the rotary tool and the metal members.
Implementation Method 2
allowing the metal in the butted portion to plastically flow by frictional heat
Data Source
AI summary
A cooling unit includes a unit main body including a bottom portion, a peripheral wall portion rising from the peripheral edge of the bottom portion, and a seal for sealing an opening of the unit main body. The unit main body is joined to the seal through a plasticized region, and a void is defined in the peripheral wall portion of the unit main body.