Fluid Line Connecting Element Overmolding Without Welding

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Solution Overview

Problem

The production of fluid lines with VDA connecting elements is complex and costly, requiring separate manufacturing of coupling plugs, welding or soldering, and subsequent anti-corrosion coating, along with a 100% leak test, which is expensive and inefficient.

Innovation Solution

A method involving an injection molding process where a fluid line is inserted into an open mold, expanded, and calibrated to form a connecting piece, allowing for overmolding with plastic without interrupting the fluid line, eliminating the need for welding, soldering, and leak tests, and incorporating anti-rotation features.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional turning and milling processes are used to manufacture coupling plugs, then the connecting elements can be produced, but the manufacturing complexity and costs increase significantly

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidmanufacturing process complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent combines multiple manufacturing operations (expansion, calibration, and injection molding) into a single integrated process. The fluid line is expanded and calibrated in-place within the injection mold cavity, eliminating the need for separate turning and milling operations to create the coupling plug. This merging of processes directly reduces manufacturing complexity while maintaining component functionality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The fluid line is pre-expanded and calibrated before the injection molding step, creating a prepared substrate that receives the coupling part. This preliminary action of expanding the fluid line allows the subsequent injection molding to proceed without additional machining steps, simplifying the overall manufacturing process.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If welding or soldering processes are used to attach coupling plugs, then connecting elements can be formed, but production time and costs increase

Engineering Contradiction:
Improveproduction efficiencyVSAvoidproduction time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent merges the attachment of the coupling part with the formation of the fluid line itself. The coupling part is injection molded directly onto the expanded and calibrated fluid line in a single continuous operation, eliminating separate welding or soldering steps. This integration directly improves productivity by removing time-consuming joining operations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The fluid line is pre-expanded and calibrated to the final dimensions before injection molding, so that the coupling part can be attached immediately without requiring subsequent machining or preparation steps. This preliminary preparation enables direct attachment, reducing overall production time.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If separate manufacturing and assembly steps are used, then connecting elements can be produced, but the number of manufacturing steps increases

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidnumber of manufacturing steps
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent combines expansion, calibration, and injection molding into a single integrated manufacturing step. The fluid line is expanded and calibrated in-place within the injection mold, and the coupling part is molded directly onto it without removal or repositioning. This merging reduces the number of discrete manufacturing steps while maintaining ease of manufacture.

Inventive Principle:
Principle #5Merging (Combining)

4Reliability

If traditional joining methods are used, then connecting elements can be attached, but anti-corrosion coating and leak testing are required

Engineering Contradiction:
Improvejoint tightnessVSAvoidadditional processing steps
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent uses a composite structure where the coupling part is made of plastic and is injection molded directly onto the metal fluid line. This composite construction creates an inherent seal between the plastic coupling part and the metal fluid line, eliminating the need for separate anti-corrosion coating and leak testing that are required with traditional metal-to-metal joining methods.

Inventive Principle:
Principle #40Composite materials

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

Significantly reduces production effort and costs by eliminating welding and soldering processes, eliminating the need for leak tests, and simplifying manufacturing steps while ensuring a secure seal and anti-rotation functionality.

Implementation Method 1

The outer diameter of the expanded length section is calibrated, i. H. formed to its intended final diameter, with which the connecting piece is finished and at the same time its outer diameter is sealed against the cavity.

Methodology Applied
Scientific EffectSealing:

Implementation Method 2

This widening of the longitudinal section according to the invention can take place, for example, via a corresponding mandrel that is inserted axially into the end section of the fluid line.

Methodology Applied
Scientific EffectMechanical expansion:

Implementation Method 3

The bell can then be removed from the connection piece, the cavity opened and the fluid line removed with the coupling part sprayed on all around.

Methodology Applied
Scientific EffectCalibration:

Data Source

PatentEP3911490B1Method and device for producing a fluid line with connecting element
Publication Date: 2023.02.08 CONTITECH MGW GMBH
  • EP3911490B1 patent drawingFigure 1~2
  • EP3911490B1 patent drawingFigure 3~4

AI summary

The invention relates to a method and a device for producing a fluid line (7) with a connecting element designed at an end section of said fluid line (7), the connecting element having a coupling portion (8) and a connection piece (70) that connects to the coupling portion (8) toward the end of the fluid line.