Punch Rivet Joining Element Shaft Design for Slug Extraction

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Solution Overview

Problem

Existing joining methods, such as solid punch riveting, generate undesired slugs that require disposal and can lead to corrosion, especially when joining parts of different materials, increasing disposal costs and complexity.

Innovation Solution

A punch rivet joining method using a joining element with a shaft region free of undercuts, where the first joining part is punched through and the joining element pushes the second part without completely piercing it, embedding the slug within the second part, resulting in a force fit without deformation of the joining element, allowing for small overlap zones and sufficient removal forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If solid punch riveting is used to join overlapping parts, then joining strength is achieved, but slugs are generated that require disposal and cause corrosion

Engineering Contradiction:

Improvejoining strengthVSAvoidslug generation and corrosion

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The harmful slug material is extracted from the joining zone by designing the punch to completely penetrate the first part and eject the slug through the second part, removing the harmful factor from the system rather than leaving it embedded in the joint

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The slug generation, traditionally a harmful byproduct, is converted into a beneficial ejection mechanism that simultaneously achieves joining and removes waste material through the same punching action

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Adaptability or versatility

If joining parts are made of different materials, then design flexibility is improved, but slug separation and disposal complexity increases

Engineering Contradiction:

Improvematerial selection flexibilityVSAvoidslug separation and disposal

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The slug is extracted from the joining zone and completely removed through the second part, eliminating the need for subsequent separation processes and simplifying disposal regardless of material composition

Inventive Principle:

Principle #2Taking out (Extraction)

3Adaptability or versatility

If punch rivet joining is used in narrow joining zones, then application range is expanded, but tool size requirements increase

Engineering Contradiction:

Improveapplication range to narrow zonesVSAvoidtool size

Core Design Contradiction:

Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The joining process is segmented into two distinct actions: punching through the first part to generate and eject the slug, and then pushing the second part without complete penetration, allowing for compact tool design suitable for narrow zones

Inventive Principle:

Principle #1Segmentation

4Strength

If the joining element is deformed to create form fit, then joining strength is improved, but removal forces decrease

Engineering Contradiction:

Improvejoining strengthVSAvoidremoval force

Core Design Contradiction:

StrengthVSForce

Solution Approach 1:

Different local qualities are applied: the first part is completely penetrated to eject the slug, while the second part is pushed without complete penetration, creating a force fit that maintains both high joining strength and sufficient removal forces

Inventive Principle:

Principle #3Local quality

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 eliminates slug generation, minimizes corrosion sensitivity, and achieves sufficient removal forces for connections like vehicle body parts, enabling efficient and cost-effective joining with minimal waste and tool size requirements.

Implementation Method 1

the joining element pushes a second joining part into the second joining part without pushing through the second joining part

Methodology Applied

Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

the shaft region of the joining element after the pushing into the second joining part is arranged so as to contact the first and second joining part so as to be impinged with a force without undercut and at least in joining direction F in the absence of a form fit

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS10239115B2Method for joining at least two parts to be joined which are arranged so as to overlap at least in a joining zone using a joining element

Publication Date: 2019.03.26 AUDI AG

AI summary

A method for joining at least two parts to be joined which are arranged so as to overlap at least in a joining zone is disclosed using a joining element which is fed to the joining zone in a joining direction and which is designed so as to be free of undercuts at least in a shaft when seen opposite the joining direction. At least one first part to be joined that interacts first with the joining element in the joining direction, is punched by means of the joining element, and the joining element is pressed into a second part to be joined without punching through the second part. The shaft of the joining element is designed so as to be free of undercuts after being pressed into the second part to be joined and is arranged so as to contact the first and the second part to be joined with a radially applied force in a form-fit-free manner at least when seen opposite the joining direction.