Braided Hose Structure With Leno Layer for Small Bend Radii
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Solution Overview
Problem
Metal braided hoses used in high-pressure hydraulic applications are prone to fatigue fracture and tensile cracks due to varying stresses and small bending radii, leading to early failure, and spiral-wound metal layer hoses are more rigid and costly.
Innovation Solution
A braided hose design incorporating a leno layer between the inner tube and braided reinforcement layer, composed of elastic or semi-elastic materials, maintains flexibility and provides mechanical reinforcement, allowing for smaller bend radii and improved fatigue resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal braided reinforcement layers are used to provide strength for high pressure applications, then the hose can withstand high hydraulic pressures, but the wires are subjected to varying stresses that result in fatigue fracture and earlier failure
Solution Approach 1:
The patent uses a composite structure combining rubber layers with textile fabric layers (instead of metal wires) to achieve both pressure resistance and fatigue resistance. The textile fabric provides reinforcement while being more resistant to fatigue from varying stresses and pressure impulses.
Solution Approach 2:
The patent changes the material parameter from metal to textile fabric, which fundamentally alters the stress response characteristics. Textile materials better accommodate varying stresses and pressure impulses without suffering from fatigue fracture, thus improving reliability while maintaining strength.
2Reliability
If spiral-wound metal layer hoses are used to improve fatigue resistance, then the hose is more robust against fatigue fracture, but the hose becomes much more rigid and cannot admit small bent radii
Solution Approach 1:
The patent employs flexible textile fabric layers that can bend and deform without breaking, maintaining both fatigue resistance and flexibility. The textile structure allows the hose to accommodate small bent radii while resisting fatigue from pressure variations.
3Reliability
If spiral-wound metal layer hoses are used to improve fatigue resistance, then the hose is more robust against fatigue fracture, but the manufacturing cost increases approx. 30%
Solution Approach 1:
The patent replaces expensive metal spiral-wound layers with more economical textile fabric layers that provide equivalent or superior fatigue resistance. This substitution significantly reduces manufacturing cost while maintaining or improving reliability.
4Ease of operation
If small bent radii are used in hydraulic applications, then the hose can be installed in tight spaces, but high bent zones create tensile force that results in tensile cracks and early hose leakage
Solution Approach 1:
The textile fabric layers act as flexible reinforcement that can bend without creating concentrated tensile stresses. The fabric structure distributes stresses evenly, allowing the hose to be installed in tight spaces with small bent radii without developing tensile cracks.
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 leno layer enhances the hose's resistance to fatigue fracture and tensile cracks while maintaining flexibility, enabling use in applications with small bend radii without the need for spiral-wound metal layers, thus being more cost-effective.
Implementation Method 1
A braided hose design incorporating a leno layer between the inner tube and braided reinforcement layer, composed of elastic or semi-elastic materials, maintains flexibility and provides mechanical reinforcement
Implementation Method 2
the wires of the metal braided layers are subjected to varying stresses. These varying stresses can result in fatigue fracture and earlier failure of the braided layer(s)
Data Source
AI summary
Braided Hose and method for manufacturing a braided hose comprising an inner tube defining a longitudinal axis. The inner tube is made of an elastic material, such as a synthetic or natural rubber, or of a thermoplastic material. A first braided reinforcement layer envelops the inner tube. An outer protective layer covers the braided layer. Wherein a leno layer is placed between the inner tube and the first braided reinforcement layer.