Occupancy Sensor Intermediate Layer for Uniform Pressure Distribution
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Solution Overview
Problem
Occupancy detection devices in vehicles face challenges due to sensitivity fluctuations caused by inhomogeneous upholstery structures, making precise positioning and reliable detection difficult, and existing solutions either complicate installation or reduce seat breathability.
Innovation Solution
An occupancy detection device with a recess in the cushion core featuring a reversibly deformable intermediate layer decoupled from the cushion core, which evenly distributes pressure to the sensor, using materials like cellular rubber or polyether foam to minimize sensitivity fluctuations and allow for uniform pore distribution, and a bearing plate for counter-pressure support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the pressure sensor is directly integrated into the cushion core, then the detection area is maximized, but the detection sensitivity fluctuates due to inhomogeneous upholstery structure
Solution Approach 1:
An intermediate layer made of reversibly deformable material is introduced between the pressure sensor and the cushion core. This intermediary layer decouples the sensor from the inhomogeneous upholstery structure, providing uniform pressure distribution to the sensor while maintaining large-area detection capability.
2Stability of the object's composition
If the pressure sensor is positioned deeper in the cushion core, then positioning stability is improved, but manufacturing density fluctuations cause large sensitivity variations
Solution Approach 1:
The intermediate layer acts as a buffer that compensates for positioning variations and manufacturing tolerances. Its reversibly deformable material properties allow it to accommodate position fluctuations while maintaining consistent pressure transmission to the sensor.
Solution Approach 2:
The intermediate layer is designed with homogeneous material properties and uniform thickness to ensure consistent pressure distribution across the sensor surface, eliminating the sensitivity variations caused by cushion core density fluctuations.
3Reliability
If a foil sensor is integrated into the seat, then occupancy detection is enabled, but seat breathability is reduced
Solution Approach 1:
A thin, flexible intermediate layer is used instead of rigid structures, allowing air permeation through the sensor assembly while maintaining detection functionality. This thin-film approach minimizes the impact on seat breathability.
4Area of stationary object
If multiple sensor cells are placed on the foam core to cover a large area, then detection coverage is improved, but the complexity of installation and positioning increases
Solution Approach 1:
Multiple sensor cells are integrated into a single unified sensor assembly with a common intermediate layer and bearing plate structure. This merging approach maintains large-area detection coverage while simplifying installation to a single modular unit.
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
Ensures consistent detection sensitivity and durability by isolating the sensor from upholstery structure imperfections, improving the mechanical pressure sensor's functionality and reducing manufacturing costs while maintaining seat breathability.
Implementation Method 1
at least one intermediate layer (5) is inserted between the bottom surface (6) of the recess (2) and the pressure sensor (7), which consists of a reversibly deformable and essentially homogeneously structured material
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to an occupancy detection device for detecting the occupancy status of a motor vehicle seat with a cushion core and with a foil pressure sensor, which is arranged in a recess on the underside of the cushion core facing away from a seated person, wherein the recess has a base surface with a size that corresponds at least to the size of the foil pressure sensor, and wherein the foil pressure sensor is held covered by a bearing plate, which is characterized in that at least one intermediate layer (5) is inserted between the base surface (6) of the recess (2) and the foil pressure sensor (7), wherein this first intermediate layer consists of a reversibly deformable and substantially homogeneously structured material.