Hall Sensor and Preloaded Magnet for Seat Position Detection
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Solution Overview
Problem
Existing sensor systems for detecting the position of a motor vehicle seat relative to the dashboard are prone to wear and tear, noise, and increased mounting costs due to the use of mechanical or electromechanical components, and non-contact systems with Hall sensors often suffer from grinding issues and external magnetic interference.
Innovation Solution
A compact sensor system comprising a Hall sensor and a preloaded magnet, arranged along the longitudinal extension of a movable component, monitors the free longitudinal end of a stationary component, eliminating the need for flux concentrators and shielding sheets, and allowing for unhindered seat adjustment and reduced mounting complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Hall sensor and preloaded magnet are placed close together to maximize signal strength, then the detection sensitivity is improved, but the Hall sensor or housing grinds against the guide rail causing noise and wear
Solution Approach 1:
A ferritic component serves as an intermediary between the preloaded magnet and Hall sensor. The magnet is positioned on one side of the ferritic component while the Hall sensor is positioned on the other side, allowing the magnetic field to penetrate through the ferritic material. This intermediary structure enables strong magnetic coupling and high detection sensitivity while maintaining sufficient physical spacing to prevent grinding contact between the sensor housing and guide rail during seat movement.
2Ease of operation
If traditional mechanical or electromechanical detector systems are used to determine seat position, then the detection function is achieved, but wear and tear occurs and unpleasant noises are generated
Solution Approach 1:
The patent replaces mechanical or electromechanical detector systems with a non-contact magnetic field-based detection system. A preloaded magnet mounted on the seat and a Hall sensor mounted on the vehicle interior trim piece detect relative position changes through magnetic field variations without any physical contact. This substitution eliminates mechanical wear and the unpleasant noises associated with traditional mechanical detectors while maintaining accurate seat position detection functionality.
3Reliability
If flux concentrators and shielding sheets are added to the sensor system, then magnetic field concentration and external interference protection are improved, but device complexity and mounting precision requirements increase
Solution Approach 1:
The patent utilizes the ferritic component (guide rail or seat rail) itself as the magnetic field concentration medium, eliminating the need for separate flux concentrators. The ferritic material's inherent magnetic properties provide sufficient field concentration and external interference protection. This approach maintains magnetic field stability and reliability while significantly reducing device complexity and mounting precision requirements, as the ferritic component is already an integral part of the seat adjustment mechanism.
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 system provides a clear and economical means to detect seat positions, reducing noise and wear, while ensuring accurate detection and optimal magnetic field concentration, enabling effective control of airbag inflation energy.
Implementation Method 1
A sensor system (10) is disclosed which includes a Hall sensor (11) and a preloaded magnet (12)... the Hall sensor and preloaded magnet are configured to be arranged along a longitudinal extension of a lengthwise movable component such that the sensor system (10) will detect relative movement of two components
Data Source
AI summary
A sensor system is disclosed for detecting positions of two at least partially ferritic components that can move relative to one another, namely a stationary component and a component that can move lengthwise along a longitudinal extension of the stationary component, which are mounted right next to one another. The sensor system can include a Hall sensor and a preloaded magnet, eliminating flux concentrators and shielding sheets. The Hall sensor and the preloaded magnet are arranged along a longitudinal extension of the movable component such that relative movement of the two components is detected by monitoring a free longitudinal end of the stationary component.