Expansion Hose Composite Reinforcement for Burst Pressure and Fatigue
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Solution Overview
Problem
Existing expansion hoses face a trade-off between high burst pressure and volumetric expansion, as well as fatigue resistance, making it difficult to simultaneously achieve the necessary characteristics for high-pressure applications like power steering systems.
Innovation Solution
The use of a textile reinforcement layer comprising a combination of high elongation nylon and low elongation polyester filaments, arranged in balanced braided or spiraled layers, with a friction layer in between, to achieve improved impulse fatigue resistance and controlled volumetric expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high strength reinforcement layers are used to increase burst pressure, then burst pressure is improved, but volumetric expansion decreases
Solution Approach 1:
The hose employs a composite reinforcement structure combining steel wire braid (for high strength and burst pressure) with textile braid layers (for controlled expansion). The steel wire provides the necessary strength to withstand high burst pressures, while the textile braid layers contribute to the desired volumetric expansion characteristics, resolving the contradiction between strength and expansion.
Solution Approach 2:
The reinforcement system is segmented into multiple functional layers: an inner textile braid layer, a steel wire braid layer, and an outer textile braid layer. Each layer serves a specific function - the inner textile layer provides initial expansion control, the steel wire layer provides high strength for burst pressure, and the outer textile layer fine-tunes the expansion characteristics. This segmentation allows independent optimization of each layer's properties.
2Strength
If reinforcement amount is increased to increase burst pressure, then burst pressure is improved, but volumetric expansion and fatigue life decrease
Solution Approach 1:
The combination of steel wire and textile materials creates a composite structure where each material contributes its superior properties. The steel wire provides high strength for burst pressure resistance, while the textile braid layers with their inherent elasticity maintain fatigue life and volumetric expansion. This composite approach avoids the trade-off present in single-material constructions where increasing reinforcement always reduces expansion and fatigue life.
Solution Approach 2:
Different reinforcement materials are applied at different locations and in different amounts based on local requirements. The steel wire braid is positioned to provide maximum strength where needed for burst pressure, while the textile braid layers are configured to maintain expansion characteristics and fatigue resistance. The braid angles and densities are locally optimized to balance strength and flexibility requirements.
3Volume of stationary object
If braid angle is adjusted to control volumetric expansion, then volumetric expansion is improved, but length stability deteriorates
Solution Approach 1:
The hose is segmented into multiple braid layers with different braid angles and orientations. The inner and outer textile braid layers can have different braid angles from the steel wire layer, allowing each layer to contribute differently to expansion and length stability. This multi-layer segmentation provides independent control over volumetric expansion and axial length stability that cannot be achieved with a single braid layer.
Solution Approach 2:
The braid layers are designed with asymmetric properties - different braid angles, different material compositions, and different layer positions. This asymmetry allows the hose to exhibit different mechanical behaviors in radial (expansion) and axial (length stability) directions, enabling independent optimization of volumetric expansion and length stability that would be impossible with symmetric, uniform braid structures.
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
This configuration allows for a higher volumetric expansion and burst pressure while maintaining excellent fatigue life, effectively addressing the contradictory requirements of expansion hoses in high-pressure applications.
Implementation Method 1
The textile reinforcement includes yarns of a first fiber material type and yarns of a second fiber material type, wherein the yarns of the first fiber material type have a higher elongation at break than the yarns of the second fiber material type
Implementation Method 2
a textile reinforcement layer comprising a combination of high elongation nylon and low elongation polyester filaments
Data Source
Figure 1~2
AI summary
An expansion hose adapted for smoothing pressure fluctuations in a hydraulic system having an inner tube, a textile reinforcement, and an outer cover. The reinforcement includes a plurality of yarns, which in turn have a plurality of filaments of first fiber material type and a plurality of filaments of second fiber material type, with first fiber type having elongation at break higher than the second fiber type by at least about 4% elongation. The expansion hose may be part of an assembly including at least one fitting, coupling, bracket, hose clamp, or other hose.