Friction Spot Welding Tool Sealing for Doughy Material Containment

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Solution Overview

Problem

Friction spot welding devices face reduced service life due to doughy material penetrating between the sleeve and pin, causing operational impairment.

Innovation Solution

Incorporating a first and second sealing gap between the sleeve and pin, with a receiving space in between, allowing doughy material to pass through the first sealing gap and collect in the receiving space, which can be accessed and removed by relative movement of the pin and sleeve, preventing further penetration and maintaining device functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sealing gaps between sleeve and pin are minimized to prevent material penetration, then material containment improves, but device complexity increases due to additional sealing structures

Engineering Contradiction:
Improveservice lifeVSAvoidstructure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The space between sleeve and pin is segmented into multiple zones: a first sealing gap for material passage, a first receiving space for collection, and a second sealing gap for containment. This segmentation allows controlled material flow while preventing uncontrolled penetration, resolving the contradiction between material containment and structural simplicity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first receiving space acts as an intermediary zone between the first and second sealing gaps. It temporarily holds the doughy material that passes through the first sealing gap, preventing it from reaching areas that would impair device functionality, thus extending service life without requiring complete sealing

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If sealing gaps are made smaller to prevent doughy material penetration, then material containment improves, but manufacturing precision requirements increase

Engineering Contradiction:
Improveservice lifeVSAvoidgap dimension
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

Instead of requiring a single tight seal, the design segments the gap into multiple zones with different functional requirements. The first sealing gap allows controlled passage, the receiving space provides buffer volume, and the second sealing gap provides containment. This reduces the precision requirement for any single gap while maintaining overall reliability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The design uses a series of partial sealing gaps rather than attempting complete sealing in one location. The first sealing gap intentionally allows partial material passage, which is then managed by the receiving space, reducing the precision burden on individual gap dimensions

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If receiving space is made larger to collect more doughy material, then material containment improves, but device volume increases

Engineering Contradiction:
Improveservice lifeVSAvoiddevice volume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The receiving space is strategically positioned and dimensioned to provide adequate collection volume only where needed - between the sealing gaps. The space is not uniformly distributed but concentrated in the critical zone, maintaining reliability while minimizing overall device volume

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

The solution effectively extends the service life of the welding device by containing and removing the doughy material, preventing it from causing operational issues and ensuring consistent performance.

Implementation Method 1

The sleeve can rotate to compress the sheet material into a doughy state so that the material can be displaced under the axial pressure of the sleeve

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the friction spot welding tool is provided with channels and cavities for cooling the pin, sleeve and punch with a cooling liquid, wherein the cooling liquid flows directly around at least the pin and the sleeve

Methodology Applied
Scientific EffectConvection cooling: Convection

Data Source

PatentEP3769895B1Device and method for friction spot welding
Publication Date: 2024.01.31 HARMS & WENDE
  • EP3769895B1 patent drawingFigure 1
  • EP3769895B1 patent drawingFigure 2A~2C
  • EP3769895B1 patent drawingFigure 3~4

AI summary

A device for friction spot welding, comprising a punch (24), a sleeve (25) arranged coaxially within the punch (24), and a pin (26) arranged coaxially within the sleeve (25). A rotary drive (29) imparts a rotary movement of the sleeve (25) and/or the pin (26) relative to the punch (24), while a linear drive (30, 31) imparts a linear movement of the sleeve (25) and/or the pin (26) relative to the punch (24). A first sealing gap (47) and a second sealing gap (54) are enclosed between the sleeve (25) and the pin (26). A first receiving chamber (55) is arranged between the first sealing gap (47) and the second sealing gap (54). The invention also relates to an associated method. In a cleaning step, the first receiving chamber (55) can be made accessible from the outside to remove any material that may have entered the chamber.