Metal-Resin Joined Body With Gradient Interface for Thermal Stress
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Solution Overview
Problem
Conventional resin-metal joined bodies experience detachment of the resin member from the metal member due to thermal stress caused by severe temperature changes, despite increased joining strength from micro-concave sections and nano-irregularities on the metal surface.
Innovation Solution
A joined body with a metal member featuring a joining surface having intersecting-direction uneven sections and a cover section with a porous structure, where the cover section forms a thinner layer than the uneven depth of the intersecting-direction uneven section and is filled with a resin member, creating a gradient layer that reduces thermal stress by altering the composition ratio of metal to resin material across the joining interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If micro-concave sections and nano-irregularities are formed on the metal surface to increase joining strength, then adhesion strength is improved, but the resin member detaches under severe temperature changes due to thermal stress
Solution Approach 1:
The invention applies local quality by creating a gradient layer with varying composition ratios of metal material and resin material across the joining interface. The layer adjacent to the metal member has a higher metal content while the outer layer has higher resin content, providing different properties at different locations to simultaneously achieve strong adhesion and thermal stress resistance
Solution Approach 2:
The invention uses composite materials by forming a gradient layer that combines metal material and resin material in varying proportions. This composite structure with continuous composition variation allows the joining interface to exhibit both the strong adhesion of metal-resin bonding and the thermal stress resistance of a gradual transition zone
2Reliability
If a gradient layer with varying composition ratio is formed to reduce thermal stress, then durability under temperature changes is improved, but manufacturing complexity increases
Solution Approach 1:
The invention applies parameter changes by systematically varying the composition ratio of metal material to resin material across the gradient layer thickness. This controlled parameter variation creates the desired stress distribution while the patent specifies concrete composition ranges (e.g., metal material 30-70 wt%, resin material 70-30 wt%) to guide manufacturing
Solution Approach 2:
The invention uses preliminary action by pre-forming the gradient layer structure with controlled composition variation before final resin injection. The metal member is prepared with a surface layer having specific composition characteristics that will serve as the foundation for the gradient structure, simplifying the overall manufacturing process
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 configuration effectively prevents resin member detachment during severe temperature changes, ensuring high adhesion strength, cold and heat durability, and sealing properties by dispersing thermal stress across the joining interface.
Implementation Method 1
the porous structure of the cover section is filled with the resin member
Data Source
AI summary
This joined body includes a metal member having a joining surface with depressions formed therein and a resin member that is joined to the metal member at the joining surface. The joined body includes an intersecting-direction uneven section and a cover section. The intersecting-direction uneven section is included in a depressed surface formation section that forms a depressed surface of the metal member that faces the depressions. The intersecting-direction uneven section is uneven in a direction intersecting a depth direction of the depression. The cover section forms a surface layer of the depressed surface formation section and covers the intersecting-direction uneven section. The cover section forms a thinner layer than an uneven depth of the intersecting-direction uneven section, and has a porous structure which is filled with the resin member.