Electric Cable Insulation Secant Modulus Optimization
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Solution Overview
Problem
The flexibility of electric cables used in vehicle power systems is limited by the bending rigidity, which is predominantly influenced by the insulator portion, leading to ambiguity in flexibility standards and difficulty in routing within small spaces.
Innovation Solution
An electric cable design featuring a conductor with a cross-sectional area of 20 mm² or more, surrounded by an insulating resin with a secant modulus of 10 to 50 MPa, and optionally a shielding conductor with a similar resin, allowing for a diameter ratio that enhances flexibility and reduces bending radius.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the insulator portion capacity is increased to provide adequate insulation for large conductors, then the electrical insulation performance is improved, but the bending rigidity increases and flexibility deteriorates
Solution Approach 1:
The patent applies parameter changes by controlling the secant modulus of the insulating resin within a specific range (10-50 MPa) and the diameter ratio within 1.15-1.40. This allows the insulator to provide adequate insulation capacity while maintaining flexibility by optimizing the material's mechanical parameters rather than simply increasing insulator thickness.
Solution Approach 2:
The patent uses composite materials by selecting insulating resins with specific properties (secant modulus 10-50 MPa) that combine adequate insulation performance with flexibility. The use of flame retardant-containing resins creates a composite material that simultaneously provides electrical insulation, flame resistance, and controlled bending characteristics.
2Ease of operation
If the bending rigidity is reduced to improve flexibility and routing ease, then the ease of wiring work is improved, but the structural integrity and insulation capacity may be compromised
Solution Approach 1:
The patent resolves this contradiction by changing the parameter of secant modulus to a specific range (10-50 MPa) that balances flexibility and structural integrity. This parameter optimization allows the cable to be easily routed while maintaining adequate insulation capacity and structural strength for reliable operation.
3Ease of operation
If the diameter ratio of cable to conductor is reduced to improve flexibility, then the bending radius decreases and routing is easier, but the insulation thickness may be insufficient
Solution Approach 1:
The patent applies parameter changes by defining the diameter ratio within 1.15-1.40 and controlling insulator thickness to provide at least 0.5 mm insulation. This ensures adequate insulation thickness while maintaining a compact cable diameter that allows easy bending and routing.
Data Source
AI summary
An electric cable for improving flexibility of an insulating resin portion of the electric cable expressed by a secant modulus value is provided. In an electric cable 10a in which an outer periphery of a conductor 11 made of wires with diameters from 0.15 to 0.5 mm and having a cross-sectional area of 20 mm2 or more is covered with an insulating resin 12 including a flame retardant, a ratio of an electric cable diameter to a conductor diameter is from 1.15 to 1.40, and a secant modulus of the insulating resin 12 is from 10 to 50 MPa.