Sandwich Joint Structure for Dissimilar Material Welding

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Solution Overview

Problem

Conventional spot welding techniques are inefficient for joining different materials, requiring complex rivets and high precision processing, leading to increased production costs and reduced design freedom, while also being time-consuming and prone to current diversion issues.

Innovation Solution

A joint structure using metallic materials with projections and penetrating parts, where a different type of material is sandwiched between them, allowing for laser, arc, or plasma welding to join similar metallic materials, eliminating the need for complex rivets and reducing operating time.

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 the process requires complex rivets and high precision processing which increases manufacturing complexity and cost

Engineering Contradiction:
Improvejoint strengthVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent extracts the complex rivet structure and high precision processing requirements from the joining system by using laser welding to directly fuse the base materials. The laser beam selectively melts and joins the metallic materials without requiring intermediate rivets or complex positioning features, thereby eliminating manufacturing complexity while maintaining joint strength.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical spot welding system with a laser-based thermal joining system. Instead of using mechanical pressure and electrical current through electrodes, the invention uses laser energy to melt and fuse the materials, eliminating the need for complex mechanical rivets and high precision mechanical alignment.

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

2Strength

If spot welding is used, then materials can be joined, but the process is time-consuming due to pressurization, cooling, and gun movement time

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

Solution Approach 1:

The patent replaces the slow mechanical spot welding process with rapid laser welding. The laser beam can be quickly positioned and applied without the need for heavy gun movement, pressurization, or extended cooling times, dramatically reducing production time while maintaining joint strength through direct material fusion.

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

Solution Approach 2:

The laser welding process enables continuous joining action without the intermittent pressurization and cooling cycles required by spot welding. The laser beam can continuously melt and fuse materials as it moves along the joint line, eliminating idle time between welding cycles and improving throughput.

Inventive Principle:
Principle #20Continuity of useful action

3Ease of operation

If spot welding gun is used, then welding can be performed, but the heavy gun requires additional time for movement and pressurization

Engineering Contradiction:
Improvewelding capabilityVSAvoidgun movement time
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The patent replaces the heavy mechanical spot welding gun with a laser welding system. The laser beam can be rapidly repositioned using optical steering mirrors or automated positioning systems, eliminating the inertia and movement time associated with heavy mechanical guns while maintaining full welding capability.

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

4Adaptability or versatility

If spot welding is used to join light metal and steel, then different materials can be connected, but the process requires sandwiching materials from above and below which limits design freedom

Engineering Contradiction:
Improvematerial joining capabilityVSAvoiddesign freedom
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts the requirement for bidirectional material sandwiching by using laser welding that can join materials from a single side. The laser beam melts the surface of both light metal and steel materials, allowing them to fuse without requiring access from both above and below, thereby improving design freedom and adaptability.

Inventive Principle:
Principle #2Taking out (Extraction)

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 solution improves throughput by reducing operating time to about 25% of spot welding, increases joint stiffness, and enhances design freedom by simplifying the joining process without the need for high precision fabrication.

Implementation Method 1

The joint structure is produced using laser, arc, or plasma as a heat source

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 2

The joint structure is produced using laser, arc, or plasma as a heat source

Methodology Applied
Scientific EffectArc: Electric Arc

Implementation Method 3

The joint structure is produced using laser, arc, or plasma as a heat source

Methodology Applied
Scientific EffectPlasma: Plasma

Implementation Method 4

The outer edge of the first projection of the first metallic material is welded to the inner edge of the first penetrating part so that the first metallic material and the second metallic material are melted and joined together

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP3712445B1Joint structure
Publication Date: 2023.03.22 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3712445B1 patent drawingFigure 1
  • EP3712445B1 patent drawingFigure 2
  • EP3712445B1 patent drawingFigure 3

AI summary

A joint structure includes a first metallic material (1) having a first projection (8); a second metallic material (3) similar in type to the first metallic material (1) and weldable to the first metallic material (1), the second metallic material (3) having a first penetrating part (11) larger in diameter or width than the first projection (8), the first projection (8) being positioned in the first penetrating part (11); and a different type of material (2) different in type from the first metallic material (1) and the second metallic material (3) and difficult to be welded to the first metallic material (1) and the second metallic material (3), the different type of material (2) having a second penetrating part (12) larger in diameter or width than the first projection (8), the rim of the second penetrating part (12) being spaced radially or widthwise from the first projection (8) by a first gap (6). The first projection (8) is positioned in the second penetrating part (12) with the first gap (6) between the first projection (8) and the second penetrating part (12). The first projection (8) is further positioned in the first penetrating part (11). Hence, the different type of material (2) is sandwiched between the first metallic material (1) and the second metallic material (3). The outer edge of the first projection (8) is welded to the inner edge of the first penetrating part (11) so that the first metallic material (1) and the second metallic material (3) are melted and joined together to compress and fix the different type of material (2) between the first metallic material (1) and the second metallic material (3), thereby fixing the first metallic material (1), the second metallic material (3), and the different type of material (2) together. A discharge opening (14) is provided in at least one of the first metallic material (1) and the second metallic material (3).