Tube-to-hose coupling with polymeric insert
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Solution Overview
Problem
Existing crimp-type tube-to-hose couplings in vehicular air conditioning systems face challenges with fluid flow restriction and costly manufacturing due to the use of rigid materials and complex metal forming operations, particularly with the need for high crimping forces and reduced throughbore diameters to achieve a seal.
Innovation Solution
A crimp-type tube-to-hose coupling design featuring a reinforced thermoplastic insert with a polymeric layer bonded between the insert and the flexible hose, using a polyamide 6 material with a glass fiber filling, and a frictional surface melting process to create a leak-tight seal without significant fluid flow restriction, simplifying manufacturing and reducing material costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigid material insert is used to resist crimping forces, then sealing reliability is improved, but manufacturing cost increases
Solution Approach 1:
The insert is made from a composite material consisting of a rigid substrate (metal or rigid plastic) and a bonded polymeric layer. The rigid substrate provides structural strength to resist crimping forces, while the polymeric layer provides sealing capability against the hose. This composite structure eliminates the need for expensive metal forming operations and allows the insert to be manufactured more economically while maintaining both sealing reliability and mechanical strength.
Solution Approach 2:
The invention changes the material parameters by bonding a polymeric layer to the rigid insert substrate. This modifies the surface properties of the insert to be more compliant and sealable against the flexible hose, while the bulk rigid substrate maintains its strength. The polymeric layer can be thermoplastic or elastomeric, providing different parameter combinations for sealing and cost-effectiveness.
2Reliability
If the insert throughbore diameter is reduced to create a seal, then sealing reliability is improved, but fluid flow performance deteriorates
Solution Approach 1:
The sealing function is localized to the interface between the polymeric layer and the hose, rather than requiring a reduced throughbore diameter. The polymeric layer provides the seal at the outer surface of the insert where it contacts the hose, while the throughbore maintains its full diameter for optimal fluid flow. This localizes the sealing action to where it is needed without restricting flow passage.
3Reliability
If high crimping forces are applied to create a seal, then sealing reliability is improved, but device complexity increases
Solution Approach 1:
The polymeric layer changes the mechanical parameters of the insert surface, making it more compliant and sealable under lower crimping forces. The polymeric material can deform more easily than rigid metal or plastic, allowing the hose to be sealed against with reduced crimp force. This simplifies the crimping process and reduces the complexity of the tooling and manufacturing process while maintaining sealing reliability.
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 simple, economical, and leak-tight connection that minimizes fluid flow restrictions while reducing manufacturing complexity and costs, ensuring effective sealing and performance in vehicular air conditioning systems.
Implementation Method 1
using a polyamide 6 material with a glass fiber filling, and a frictional surface melting process to create a leak-tight seal
Data Source
Figure 1~2
Figure 3~5
AI summary
A tube-to-hose coupling includes an elongated hollow insert connected between an end of the tube and defining an insert receiving portion and the end of the hose defining an insert receiving portion. The insert is disposed in the insert receiving portion of the tube end and the insert receiving portion of the hose end in fluid tight sealing relation. Thermoplastic polymeric material is bonded between the insert and the hose during insertion of the insert into the bore of the hose. The tube is connected to the insert and the hose by plastic deformation. In one embodiment the polymeric material is a layer defining the internal bore of the hose. In another, the polymeric material defines an outer layer on the insert.