Seat Occupancy Sensor Disc Spring Snapping Mechanism
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Solution Overview
Problem
Existing seat occupancy sensors for motor vehicles face challenges in defining a precise switching point and achieving a compact design suitable for integration in the rear seat area, where space is limited and the switching travel is often short, leading to inaccurate detection of seat occupancy.
Innovation Solution
A seat occupancy sensor with a disc spring and a switch button that transitions from an initial to a snapped state, allowing for a defined switching point and a compact overall height, enabling integration under the rear seat surface, where the switch button aligns with the seat surface and the disc spring connects electrically conductive spring elements upon sufficient force application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a disc spring with long switching travel is used to achieve a defined switching point, then the switching point precision is improved, but the overall height of the sensor increases making it impossible to integrate into rear seat area
Solution Approach 1:
The patent implements nesting by placing the disc spring inside a housing structure, and further nesting the electrical contacts and switching elements within the disc spring assembly. This nested arrangement allows the sensor components to be compactly organized, reducing the overall height while maintaining the functional switching travel distance through the disc spring's controlled deformation.
Solution Approach 2:
The patent transitions from a linear switching mechanism to a radial/disc-based mechanism. The disc spring operates in a radial direction rather than a purely linear axis, allowing the switching action to occur within a compact height envelope. The electrical contacts are arranged radially around the disc spring, enabling switching functionality without requiring long axial travel.
2Ease of manufacture
If the switching travel is kept very short to enable compact design for rear seat integration, then the ease of installation is improved, but the switching point cannot be precisely defined
Solution Approach 1:
The patent changes the geometric parameters of the disc spring, specifically its radius and thickness, to optimize the switching characteristics. By carefully selecting these parameters, the disc spring achieves a defined snap-through behavior at a specific radial displacement, providing a precise switching point even within the constrained short travel distance required for compact rear seat installation.
3Adaptability or versatility
If a compact sensor design is used to fit under rear seat surface, then the adaptability to rear seat installation is improved, but the switching mechanism cannot achieve sufficient travel distance for reliable switching
Solution Approach 1:
The patent employs a disc spring with curved geometry instead of a linear spring. The radial curvature of the disc spring allows it to store and release elastic energy efficiently within a compact volume. The curved structure enables the spring to achieve sufficient effective switching travel through radial deformation, fitting within the height constraints of rear seat installation while maintaining reliable switching action.
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
This design allows for accurate detection of seat occupancy by enabling a clear distinction between the basic and switching states, facilitating integration in the rear seat area and improving the reliability of systems like airbag deployment and ventilation control.
Implementation Method 1
a disc spring (5) arranged in the housing, wherein the disc spring has a concave side, a convex side, an outer edge and an inner edge and the disc spring can further be brought into a starting state and into a snapped-through state
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a seat occupancy sensor (1), comprising a plate spring (5) arranged in the housing, the plate spring (5) being in operative connection with an electrically conductive switching tongue (16), wherein, both in the basic state and in the switching state, a region of the switching tongue (16), which is associated with the first electrical contact (3), is electrically connected to the first electrical contact (3), and wherein, in the switching state, the switching button (6) is supported on the inner edge (14) of the plate spring (5), the plate spring (5) being present in its fully compressed state and the second electrical contact (4) being electrically connected to the region of the switching tongue (16), which is associated with the first electrical contact (3).