Heater Sheet Wire Loop Design for Thermal Expansion
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Solution Overview
Problem
Vehicle exterior components with heater sheets installed in front of decorative main bodies face issues with thermal expansion and contraction, leading to potential breakage of heating wires due to repeated temperature changes, which affects the detection performance of millimeter wave radar devices by attenuating millimeter waves.
Innovation Solution
A vehicle exterior component design featuring a heater sheet with a heating wire routed on the back surface, where the extending portion is bent along the outer circumference of the decorative main body, with wire lengths adjusted to accommodate thermal expansions and contractions, ensuring the heating wire adapts to temperature changes without breaking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the heater sheet is installed on the front side of the decorative main body to melt ice and snow, then the snow melting function is improved, but the heating wire may break due to thermal expansion and contraction of the sheet base
Solution Approach 1:
The patent changes the physical state and dimensions of the heating wire by forming it into a loop shape with specific diameter (D1) and width (W1), and by controlling the thickness (t1) to be 0.03-0.07 times the diameter. These parameter changes allow the heating wire to accommodate thermal expansion and contraction of the sheet base without breaking, while maintaining its heating function.
Solution Approach 2:
The heating wire is designed with a loop shape that can dynamically adapt to the expansion and contraction movements of the sheet base. The loop structure allows the wire to deform elastically with temperature changes rather than maintaining a rigid fixed shape, preventing breakage while preserving the snow melting capability.
2Power
If the heating wire is routed on the back surface of the sheet base, then the heating efficiency is improved, but the wire is more susceptible to damage from thermal stress
Solution Approach 1:
The patent specifies precise parameter relationships for the heating wire: thickness t1 is 0.03-0.07 times the diameter D1, and the loop width W1 is 0.05-0.15 times the diameter D1. These optimized parameters ensure the wire has sufficient flexibility to withstand thermal stress while maintaining effective heating contact with the sheet base.
Solution Approach 2:
The loop-shaped heating wire can dynamically adjust its shape in response to thermal expansion and contraction of the sheet base. This dynamic adaptability allows the wire to remain intact under thermal stress while still efficiently transferring heat to melt snow and ice on the vehicle exterior.
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 design effectively prevents heating wire breakage and maintains millimeter wave detection performance by allowing the wire to adapt to temperature changes, ensuring efficient melting of ice and snow on the vehicle's surface.
Implementation Method 1
The heating wire is configured to generate heat when energized
Implementation Method 2
A wire length of the heating wire in the bent portion is set to a length that allows the heating wire to change a shape to adapt to expansions and contractions of the sheet base in the bent portion caused by changes in an ambient temperature
Data Source
AI summary
A vehicle exterior component includes a decorative main body and a heater sheet that includes a heating wire and a sheet base made of a plastic. The heating wire is routed on the back surface of the sheet base. The heater sheet includes a heating main body that is arranged to be closer to a front side than the decorative main body, and an extending portion that is bent along the outer circumference of the decorative main body to be arranged at a position closer to a back side than a front surface of the decorative main body. The extending portion includes a bent portion along the outer circumference. The wire length of the heating wire in the bent portion is set to a length that allows the heating wire to change shape to adapt to expansions and contractions of the sheet base in the bent portion.