Foamed Polyurethane Cable Sheath Reduces Mass and Improves Flexural Fatigue
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Solution Overview
Problem
Existing electrical cables face challenges in achieving improved mechanical and processing properties such as reduced mass, easier stripping, enhanced torsional behavior, and increased flexural fatigue strength, while maintaining high thermal stability and recyclability.
Innovation Solution
The cable features a jacket composed of thermoplastic polyurethane elastomer with a multi-layer structure, including foamed and unfoamed layers, which reduces mass and improves mechanical resistance and stripping ease through a damping effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the cable uses solid polyurethane sheath, then mechanical strength and structural integrity are maintained, but mass is increased and stripping difficulty increases
Solution Approach 1:
The patent applies foamed polyurethane material with closed-cell structure to the cable sheath and insulation layers. The foam structure introduces air pockets throughout the material, reducing density and mass while maintaining mechanical integrity through the closed-cell configuration that prevents structural collapse.
Solution Approach 2:
The patent implements a multi-layer construction with different foam densities and structures in different regions. The inner layer has different characteristics than the outer layer, allowing optimization of local properties - softer inner layer for conductor protection and easier stripping, outer layer for mechanical strength and environmental resistance.
2Strength
If the cable uses solid polyurethane sheath, then structural integrity is maintained, but torsional behavior and flexural fatigue strength deteriorate
Solution Approach 1:
The foamed structure with closed cells provides inherent flexibility and energy absorption capabilities. The air-filled cells act as small shock absorbers that dampen torsional stresses and flexural fatigue, improving the cable's ability to withstand repeated bending and twisting while maintaining overall structural integrity.
3Strength
If the cable uses solid polyurethane sheath, then mechanical pressure resistance is maintained, but damping effect and mechanical resistance deterioration
Solution Approach 1:
The closed-cell foam structure provides both mechanical strength and damping. The cell walls resist external pressure while the air-filled cells compress and rebound, absorbing mechanical shocks and vibrations. This dual functionality resolves the contradiction between maintaining pressure resistance and providing damping.
4Ease of manufacture
If the cable uses thermoplastic polyurethane elastomer, then recyclability is improved, but thermal stability may deteriorate
Solution Approach 1:
The patent uses thermoplastic polyurethane elastomer (TPU) which combines the recyclability of thermoplastics with the thermal and mechanical properties of elastomers. The multi-layer foam construction with specific density ratios optimizes both thermal resistance and recyclability, allowing the cable to be processed and recycled while maintaining adequate thermal stability for automotive applications.
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 effectively reduces the cable's specific mass, enhances torsional behavior, and increases mechanical pressure resistance and flexural fatigue strength, while maintaining high thermal stability and recyclability.
Implementation Method 1
the outer layer and/or the inner layer is/are a foamed layer(s) 4
Implementation Method 2
Due to the spongy structure of a foamed layer, which can in particular be a gas-filled, closed-cell material
Implementation Method 3
the mechanical pressure resistance and the flexural fatigue strength due to a damping effect of the foamed layer
Implementation Method 4
This polyurethane material is, in particular, a thermoplastic material that can be melted again and can therefore easily be recycled
Data Source
Figure 1
AI summary
The invention relates to a sheathed electric lead, comprising at least one electric conductor (1) having insulation (2) and a sheathing (3) made of plastic. In order to improve the mechanical properties, according to the invention the sheathing (3) comprises a foamed layer (4).