Arc-Welded Joint Structure for Dissimilar Material Joining

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Solution Overview

Problem

Conventional spot welding techniques are inefficient for joining different types of materials, particularly light metals and steels, due to limitations in design freedom, high production costs, and time-consuming processes, and often result in insufficient joint strength and stiffness.

Innovation Solution

A joint structure is developed using arc welding, where a first metallic material with a projection and a second metallic material, similar in type, sandwich a different type of material with a penetrating part, allowing for precise positioning and compression through controlled gap sizes to facilitate reliable joining, reducing production time and increasing stiffness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If spot welding is used to join different types of materials, then joint strength can be achieved, but production time increases due to additional operations (pressurization, cooling, etc.)

Engineering Contradiction:
Improvejoint strengthVSAvoidproduction time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The invention extracts and eliminates the intermediate different-type material from the welding path, allowing direct arc welding between similar metallic materials. The through-hole in the intermediate material enables the welding arc to pass through and directly melt and join the first and second metallic materials, removing the time-consuming pressurization and cooling steps required by conventional spot welding of dissimilar materials.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the mechanical pressurization system of spot welding with an arc welding thermal process. Instead of using electrodes to mechanically pressurize and join materials, the invention uses an arc to melt the metallic materials and form a weld pool that joins them together, eliminating the need for mechanical pressurization equipment and reducing cycle time.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Strength

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

Engineering Contradiction:
Improvejoining capabilityVSAvoiddesign freedom
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The invention uses an arc as an intermediary welding method that can access joints from a single side. The arc passes through the through-hole in the intermediate material to reach the second metallic material, enabling welding in configurations where conventional spot welding guns cannot access both sides of the joint, thereby increasing design freedom.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Strength

If spot welding is used, then materials can be joined, but equipment space requirements increase due to gun size and pressurization needs

Engineering Contradiction:
Improvejoining capabilityVSAvoidequipment space
Core Design Contradiction:
StrengthVSArea of stationary object

Solution Approach 1:

The invention replaces the bulky mechanical pressurization system with a compact arc welding setup. The arc welding equipment requires minimal space compared to spot welding guns and their associated pressurization mechanisms, reducing the overall equipment footprint and space requirements for the welding operation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Productivity

If arc welding is used to join dissimilar materials, then production time is reduced, but direct welding of dissimilar materials is difficult

Engineering Contradiction:
Improveproduction speedVSAvoidweldability of dissimilar materials
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention segments the welding process into two parts: the intermediate different-type material provides structural support and positioning, while the through-hole allows the arc to directly weld the similar metallic materials. This segmentation enables the use of arc welding for high-speed production while maintaining reliable joints by welding compatible materials directly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The intermediate different-type material acts as a mediator that facilitates arc welding between similar metallic materials. The through-hole in this intermediate material allows the arc to pass through and create a reliable weld between the first and second metallic materials, solving the weldability issue of dissimilar materials while maintaining high production speed.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 significantly reduces production cycle time, enhances joint stiffness, and increases design freedom by enabling efficient joining of dissimilar materials with improved reliability and reduced operational time compared to traditional spot welding.

Implementation Method 1

The first metallic material and the second metallic material are melted and joined together inside the first through-hole

Methodology Applied
Scientific EffectArc heating: Electric Arc

Implementation Method 2

The first metallic material and the second metallic material are melted and joined together inside the first through-hole

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 3

The first metallic material and the second metallic material are melted and joined together inside the first through-hole to compress and fix the different type of material

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP3950203B1Joint structure
Publication Date: 2023.08.23 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 in type to the first metallic material and weldable to the first metallic material, and a different type of material having a first penetrating part and sandwiched between the first metallic material and the second metallic material, the different type of material being different in type from the first metallic material and the second metallic material and difficult to be welded to the first metallic material and the second metallic material. The first projection is smaller in diameter or width than the first penetrating part and is spaced from the rim of the first penetrating part by a first gap. The first projection is positioned in the first penetrating part and is spaced from the second metallic material by a second gap in the thickness direction of the first penetrating part. The second gap has a size of a predetermined percentage of the thickness of the first projection of the first metallic material to which arc welding id applied. 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, so that the different type of material, the first metallic material, and the second metallic material are fixed together.