Load Detection Sensor Metal Plate Temperature Stability
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Solution Overview
Problem
Existing load detection sensors in seating systems are prone to erroneous detection due to temperature changes, which can cause resinous films to bend and incorrectly register loads, especially in high-temperature environments.
Innovation Solution
A load detection sensor unit with a metal plate and a pressing member that is harder than the sheet cushion, where the metal plate is designed to bend and contact electrodes when pressed, ensuring accurate seating detection while minimizing temperature-induced errors, and includes features like a pressure receiving surface and movement regulation members to prevent unnecessary contact and creep.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a resinous film is used as the load detection sensor, then the device can be lightweight and easy to manufacture, but the film strength decreases with temperature increase causing erroneous detection
Solution Approach 1:
The patent uses a composite structure combining resinous film and metal plate. The resinous film provides ease of manufacture and lightweight properties, while the metal plate overlay provides temperature stability and prevents erroneous detection. This composite approach allows both materials to contribute their advantageous properties to the overall sensor system.
Solution Approach 2:
The patent changes the physical parameters of the sensor system by introducing a metal plate with different thermal properties than the resinous film. The metal plate's overlay reflects infrared light and provides structural support that compensates for the resinous film's temperature-dependent strength variations, thereby maintaining reliable detection across temperature ranges.
2Reliability
If a metal plate is added to cover the opening, then temperature-induced bending is suppressed, but the device complexity increases
Solution Approach 1:
The patent employs thin metal plate overlays that are flexible enough to conform to the sensor structure while providing sufficient rigidity to prevent temperature-induced bending of the resinous film. The thin-film approach minimizes added complexity while maintaining the reliability benefits of metal's thermal stability.
Solution Approach 2:
The combination of resinous film and metal plate creates a composite structure where each layer performs its specialized function. The resinous film maintains its sensing capabilities while the metal overlay provides thermal stability, achieving reliable temperature-compensated detection without excessive structural complexity.
3Reliability
If the metal plate is made more rigid to prevent bending, then temperature stability improves, but the seating detection sensitivity decreases
Solution Approach 1:
The patent uses thin metal plate overlays that maintain flexibility to allow bending under seating load while providing sufficient rigidity to resist temperature-induced deformation. The thin-film design enables the metal plate to respond to both thermal expansion and mechanical loading, maintaining measurement precision across varying conditions.
Solution Approach 2:
The patent optimizes the metal plate's physical parameters including thickness, material composition, and overlay pattern to achieve the right balance between rigidity for temperature stability and flexibility for load response. By carefully controlling these parameters, the system maintains both reliability and measurement precision.
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 suppresses erroneous seating detection by ensuring the metal plate bends appropriately under load and remains stable with temperature changes, allowing for precise detection of seating without false triggers, even in varying environmental conditions.
Implementation Method 1
since the metal plate has elasticity and the elasticity does not change so much depending on the temperature
Implementation Method 2
a pressing member that includes a pressing portion pressed against the sheet cushion of a seat device and harder than the sheet cushion
Data Source
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AI summary
A load detection sensor unit 1A includes: a load detection sensor 5A which includes a pair of electrodes facing each other with a predetermined gap interposed therebetween and a metal plate covering at least a part of one electrode; and a pressing member that includes a pressing portion 43 pressed against a sheet cushion of a seat device and harder than the sheet cushion, and the pair of electrodes contacts each other when the metal plate is bent in a case in which the pressing portion 43 presses a part of the metal plate.