Heat-Resistant Wire Multilayer Insulation for Railroad Vehicles
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Solution Overview
Problem
Existing heat-resistant wires and cables for railroad vehicles face challenges in achieving both high mechanical characteristics and long-term water-immersion properties while maintaining a small diameter, with current materials being expensive and prone to hydrolysis.
Innovation Solution
A heat-resistant wire with a multilayer insulation structure, where the outermost layer is a cross-linked flame-retardant resin composition comprising polyolefin grafted with polyamide, and the inner layer is formed from low-polarity polymers like high-density polyethylene, providing excellent mechanical and water-resistant properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fluorine resin or engineering plastic is used as covering material, then heat resistance and mechanical characteristics are improved, but cost increases and fitting properties deteriorate
Solution Approach 1:
The covering material is divided into multiple layers: an inner layer made of fluorine resin for heat resistance and mechanical strength, and an outer layer made of polyolefin for flexibility and fitting properties. This segmentation allows each layer to optimize its function without compromising the other.
Solution Approach 2:
The patent uses a composite structure combining fluorine resin (for high temperature resistance and mechanical properties) with polyolefin (for flexibility and ease of installation). This composite approach achieves both heat resistance and good fitting properties that single materials cannot provide alone.
2Weight of moving object
If conductor cross sectional area is reduced to decrease weight, then weight reduction is achieved, but current carrying capacity decreases
Solution Approach 1:
The patent changes the material parameters of the covering layers to optimize the balance between weight and current carrying capacity. The fluorine resin inner layer provides high strength-to-weight ratio while maintaining electrical insulation, allowing thinner conductors to be used without compromising performance.
3Length of stationary object
If thickness of covering material is reduced to decrease diameter, then diameter is reduced, but mechanical characteristics and insulation resistance deteriorate
Solution Approach 1:
The covering is segmented into two functional layers: the inner fluorine resin layer provides mechanical strength and heat resistance with minimal thickness, while the outer polyolefin layer provides additional protection and flexibility. This allows reduced overall diameter while maintaining necessary mechanical properties.
Solution Approach 2:
Different parts of the covering have different thicknesses and material properties optimized for their specific functions. The inner layer is thinner and focused on heat resistance, while the outer layer provides mechanical protection, achieving overall diameter reduction without sacrificing essential properties.
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 results in heat-resistant wires and cables with improved mechanical characteristics and long-term water-immersion properties, suitable for railroad vehicles, while maintaining a small diameter and using relatively cheap materials.
Implementation Method 1
an outermost layer of the insulation comprises a flame-retardant resin composition having a melting point of not less than 200° C. and is cross-linked by exposure to ionizing radiation
Data Source
AI summary
A heat-resistant wire includes a conductor, and an insulation including not less than two layers and covering the conductor. An outermost layer of the insulation includes a flame-retardant resin composition having a melting point of not less than 200° C. and is cross-linked by exposure to ionizing radiation, the flame-retardant resin composition including a polyolefin grafted with polyamide as a base polymer.