Overmolded End Piece Anchoring Polyamide Pipes

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Solution Overview

Problem

Existing end fittings for fluid transport circuits in motor vehicles, particularly those near the engine, face challenges with severe temperature and vibration stresses, leading to potential leaks and ignition risks, and current manufacturing methods using metal bodies are costly and limit the use of polyamide pipes due to rounded reliefs that require elastomer pipes and clamps, increasing costs and assembly time.

Innovation Solution

A tubular metal end piece with a molded plastic body featuring sharp-edged reliefs for anchoring in polyamide pipes, combining the mechanical strength of metal with the anchoring capability of plastic, produced through forming processes like deep drawing or hydroforming, and incorporating a plastic sleeve with a radially movable lock and sealing elements for secure connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If metal bodies are used for end pieces to withstand stress, then mechanical strength is improved, but manufacturing cost increases and production complexity increases

Engineering Contradiction:
Improvemechanical strengthVSAvoidmanufacturing cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The end piece combines a metal body (for mechanical strength and stress resistance) with an overmolded plastic body (for cost-effective production and anchoring function). This composite structure allows each material to contribute its optimal properties: metal provides the required strength while plastic enables economical forming processes and integration of anchoring reliefs.

Inventive Principle:
Principle #40Composite materials

2Reliability

If rounded reliefs are produced on metal bodies, then anchoring function is improved for elastomer pipes, but adaptability to polyamide pipes deteriorates

Engineering Contradiction:
Improveanchoring functionVSAvoidpipe material compatibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The plastic body is provided with sharp-edged reliefs specifically at the anchoring location where pipe contact occurs. This localized feature design allows the reliefs to effectively bite into polyamide pipe walls while the overall composite structure maintains compatibility with different pipe materials. The sharp edges concentrate stress at precise points for effective anchoring without requiring the entire body to be optimized for one pipe type.

Inventive Principle:
Principle #3Local quality

3Reliability

If elastomer pipes are used with rounded reliefs, then anchoring is improved, but weight and bulk increase

Engineering Contradiction:
ImproveanchoringVSAvoidpipe weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The invention changes the geometry parameter of the reliefs from rounded to sharp-edged, and changes the material parameter from elastomer to plastic. These parameter changes enable effective anchoring in rigid polyamide pipes while using lighter, less bulky plastic material instead of heavy elastomer pipes. The sharp edges provide mechanical interlocking with polyamide without requiring the flexibility and bulk of elastomer materials.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If clamps are added to hold end pieces on pipes, then connection reliability is improved, but assembly time and device complexity increase

Engineering Contradiction:
Improveconnection reliabilityVSAvoidassembly time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The anchoring function previously requiring separate clamps is merged into the plastic body itself through integrated sharp-edged reliefs. The plastic body with its anchoring reliefs directly engages the pipe wall, eliminating the need for additional clamping components. This integration reduces the number of parts, simplifies the assembly process, and decreases assembly time while maintaining connection reliability.

Inventive Principle:
Principle #5Merging (Combining)

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 provides a cost-effective and lightweight connection that securely anchors in polyamide pipes, reducing the risk of leaks and assembly defects, while maintaining mechanical strength and facilitating efficient production.

Implementation Method 1

at least one plastic body (7) is molded over at least an external part of the first end portion (1.1) of the metal body (1)

Methodology Applied
Scientific EffectOvermolding:

Data Source

PatentEP2570710B1Umgossener Trichter zur Verbindung einer Kanalisation mit einem Element eines Flüssigkeitstransportkreislaufs
Publication Date: 2016.03.09 PARKER HANNIFIN MANUFACTURING FRANCE SAS
  • EP2570710B1 patent drawingFigure 1~2

AI summary

The endpiece has a tubular metal body (1) comprising an end portion (1.1) to be introduced into a pipe, and another end portion (1.2) connected to a connecting unit (2) in a plastic case (3). The connecting unit connects the latter end portion to a fluid transporting circuit element. A plastic body (7) is molded on an outer part of the former end portion. The plastic body externally comprises a sharp edged annular anchoring relief (8) for anchoring the endpiece in the pipe. An end portion (7.1) of the plastic body extends beyond the former end portion of the metal body along axial direction.