Piezoresistive Thread Pressure Sensor for Vehicle Seats
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Solution Overview
Problem
Existing pressure sensors, particularly those used in vehicle seats for occupancy detection, require a solution that balances robustness, reliability, and sensitivity while maintaining air and moisture permeability, which current technologies fail to achieve effectively.
Innovation Solution
A pressure sensor utilizing piezoresistive threads made from materials like polymers with metal ions and carbon particles, woven into a textile element, which changes electrical resistance under compressive force, offering enhanced strength and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional conductive fabrics or membranes are used in pressure sensors, then electrical conductivity is achieved, but strength and robustness are insufficient
Solution Approach 1:
The patent employs composite materials by combining piezoresistive material with conductive core threads to create piezoresistive threads. This composite structure integrates the strength and durability of the core thread with the pressure-sensitive electrical resistance properties of the piezoresistive material, resolving the contradiction between conductivity and mechanical robustness.
Solution Approach 2:
The patent changes the material parameters by using piezoresistive materials whose electrical resistance changes in response to pressure. This allows the textile element to maintain mechanical strength while providing the necessary electrical conductivity and pressure sensitivity for sensor functionality.
2Strength
If dense fabric structures are used to improve strength, then mechanical robustness increases, but air and moisture permeability deteriorates
Solution Approach 1:
The patent utilizes porous textile structures that allow air and moisture to pass through while maintaining mechanical strength. The textile element's open weave pattern provides adequate permeability for comfort in vehicle seat applications while the piezoresistive threads embedded within provide the necessary structural integrity and sensing capability.
3Measurement precision
If piezoresistive material is applied as coating or impregnation, then pressure sensitivity is achieved, but manufacturing complexity increases
Solution Approach 1:
The patent achieves pressure sensitivity by incorporating piezoresistive material into the thread structure itself during manufacturing, rather than applying coatings or impregnations to finished fabrics. This approach integrates the sensing function into the base material, simplifying the overall manufacturing process while maintaining pressure sensitivity.
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 provides a robust, reliable, and sensitive pressure sensor with improved air and moisture permeability, enabling precise occupancy detection and broader applications with increased stability and fine texture.
Implementation Method 1
at least one thread of the textile element is designed as a piezoresistive thread, which is at least partially made of a piezoresistive material that changes its electrical resistance under the action of compressive force
Data Source
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AI summary
The invention relates to a pressure sensor with at least one textile element comprising threads, at least some of which are electrically conductive. According to the invention, at least one thread of the textile element is designed as a piezoresistive thread, which is at least partially made of a piezoresistive material that changes its electrical resistance under the influence of pressure. The invention further comprises a method for manufacturing this pressure sensor.