Projection Joint Structure for Dissimilar Material Arc Welding

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Solution Overview

Problem

Conventional spot welding methods are inefficient for joining different materials, particularly light metals and steels, due to high production costs, limited design freedom, and time-consuming processes, and often result in incomplete welds and misalignment issues.

Innovation Solution

A joint structure using arc or plasma welding with projections and gaps to securely join dissimilar materials, where a first and second metallic material are welded together with a different material sandwiched between, utilizing projections and gaps to ensure proper alignment and compression during welding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If spot welding is used to join different materials, then joining capability is achieved, but production time increases and throughput decreases

Engineering Contradiction:

ImprovethroughputVSAvoidproduction time

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The patent extracts the problematic intermediate material (aluminum sheet) from the welding path by creating a through-hole, allowing direct welding between steel sheets without the time-consuming steps of material deformation and electrode pressurization required by conventional spot welding of dissimilar materials

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The through-hole acts as an intermediary structure that enables direct welding of steel sheets while accommodating the aluminum sheet within the hole, eliminating the need for complex intermediate joining processes and reducing production time

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If conventional spot welding is used, then joining of materials is achieved, but design freedom is limited due to gun access requirements

Engineering Contradiction:

Improvedesign freedomVSAvoidgun access requirements

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent segments the aluminum sheet into a removable intermediate material that is placed within the through-hole, allowing welding to be performed from one side only and enabling complex geometries that would be inaccessible to conventional dual-side spot welding guns

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of requiring the welding gun to access both sides of the joint as in conventional spot welding, the patent inverts the approach by enabling one-sided welding through the through-hole, thereby simplifying gun access requirements and increasing design freedom

Inventive Principle:

Principle #13The other way round (Inversion)

3Productivity

If arc welding is used to join dissimilar materials, then joining speed increases, but misalignment and depression issues occur

Engineering Contradiction:

Improvewelding speedVSAvoidalignment precision

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by pre-forming protrusions on the steel sheets that extend into the through-hole, which automatically guide and position the steel sheets relative to each other and the aluminum sheet, preventing misalignment and depression during the high-speed arc welding process

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces the mechanical pressurization system of spot welding with an arc welding thermal process, using the heat-affected zone and molten metal flow to achieve joining while the protrusions maintain alignment, thereby increasing welding speed without sacrificing precision

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

This method allows for reliable joining of dissimilar materials with improved throughput, reduced production time, increased stiffness, and enhanced design freedom, while avoiding defects and misalignment.

Implementation Method 1

arc or plasma as a heat source

Methodology Applied

Scientific EffectArc welding: Electric Arc

Implementation Method 2

arc or plasma as a heat source

Methodology Applied

Scientific EffectPlasma welding: Plasma

Implementation Method 3

The first metallic material and the second metallic material are melted and joined together inside the first penetrating part to compress and fix the different type of material

Methodology Applied

Scientific EffectCompression: Compression

Data Source

PatentUS12454970B2Joint structure

Publication Date: 2025.10.28 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A joint structure includes a first metallic material having a first projection, a second metallic material similar to and weldable to the first metallic material, and a different material having a first penetrating part and sandwiched between the first and second metallic materials, the different material being difficult to weld to the first and second metallic materials. The first projection is smaller than the first penetrating part and is spaced from the rim of the first penetrating part. The first projection is positioned in the first penetrating part and spaced from the second metallic material by a gap. The gap has a size of a predetermined percentage of the thickness of the first projection to which arc welding is applied. The first and second metallic materials are melted and joined together inside the first penetrating part to compress and fix the different material, so all three are fixed together.