Recess-Sealed Dissimilar-Metal Joint for Moisture Blocking

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Solution Overview

Problem

Existing joint structures between dissimilar metal materials are prone to electrolytic corrosion due to moisture ingress, which compromises joint strength.

Innovation Solution

A joint structure featuring a recess on the overlapped surfaces of dissimilar materials, filled with a sealing material injected through injection holes, to prevent moisture entry and enhance sealing properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If dissimilar metal materials are joined by welding through a through-portion, then joining strength is achieved, but moisture enters through gaps causing electrolytic corrosion

Engineering Contradiction:

Improvejoining strengthVSAvoidelectrolytic corrosion

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

A sealing material is introduced as an intermediary substance between the dissimilar metal materials to prevent moisture from reaching the overlapping surfaces. The sealing material fills the gap created by the recess, acting as a barrier that blocks the harmful moisture while allowing the welding process to proceed through the through-portion.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The recess is formed on the overlapped surfaces before the welding process. This preliminary action creates a designated space that will later be filled with sealing material, preventing moisture ingress before it can cause electrolytic corrosion. The recess preparation occurs in advance of the actual joining operation.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If a recess is formed to prevent moisture entry, then electrolytic corrosion is reduced, but device complexity increases

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The recess is formed only in specific localized areas where the dissimilar metal materials overlap, rather than modifying the entire structure. This localized approach prevents moisture entry at critical interfaces while minimizing the overall structural complexity and maintaining simplicity in non-critical areas.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The sealing function is segmented into a separate component (the sealing material) that is injected into the recess, rather than integrating the sealing function directly into the base metal structures. This segmentation allows the sealing mechanism to be added independently without fundamentally redesigning the entire joint structure.

Inventive Principle:

Principle #1Segmentation

3Object-affected harmful factors

If sealing material is injected to close gaps, then moisture prevention is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvemoisture ingressVSAvoidmanufacturing complexity

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The sealing material is injected into the recess using fluid injection techniques, leveraging hydraulic or pneumatic principles to deliver the sealing material through injection holes. This method provides an efficient, controlled way to fill the recess and close gaps without requiring complex mechanical assembly operations.

Inventive Principle:

Principle #29Pneumatics and hydraulics

Solution Approach 2:

The traditional mechanical sealing methods (such as gaskets or tight fits) are replaced with a material injection process. Instead of relying on mechanical components to block moisture, the sealing function is achieved by injecting a sealing material that flows into and fills the recess, simplifying the manufacturing process.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 effectively reduces electrolytic corrosion and secures joining strength by ensuring a tight seal between overlapping metal surfaces, even after welding, thereby improving the durability of the joint.

Implementation Method 1

the recess is provided with a sealing material injected from the injection hole, the sealing material closing a gap between the overlapped surfaces of the first member and the second member

Methodology Applied

Scientific EffectSealing:

Implementation Method 2

the dissimilar material and the first metal material are fixed to each other by a compressive fixing force between the flange and the first metal material due to solidification shrinkage of the filler material onto the first metal material

Methodology Applied

Scientific EffectSolidification shrinkage:

Implementation Method 3

a filler material (welding wire) is arc-welded through a through-portion of the dissimilar material

Methodology Applied

Scientific EffectArc welding: Welding

Data Source

PatentUS12134148B2Joining structure and joining method

Publication Date: 2024.11.05 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A second member has a through-portion penetrating toward a first member. An overlapped surface of the second member with the first member includes a recess. The recess is recessed so as to surround an entire periphery of the through-portion. A sealing material is injected into the recess from an injection hole to close a gap between overlapped surfaces of the first member and the second member.