Vehicle Latch Hall Sensor Activation Using Ferrous Metal Traces
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Solution Overview
Problem
Hall-effect sensors in latching systems face challenges due to inconsistent magnetic field strength at varying air gaps, requiring tight tolerances and larger printed circuit boards (PCBs), which increases costs and complicates design, especially when sensors need to be positioned on different planes or when detecting multiple levers.
Innovation Solution
The use of stamped ferrous metal traces to transfer the magnetic field from a magnet to a hall-effect sensor, allowing for flexible routing and activation at multiple points, reducing the size of the PCB and enabling detection on different planes with a single flat PCB, and utilizing horizontal magnet polarity to demagnetize the traces for accurate ON/OFF signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditional hall-effect sensor arrangement with perpendicular magnet polarity is used, then the sensor can detect magnetic field strength, but the magnetic field strength is inconsistent at different air gap sizes requiring tight tolerances and larger PCB area
Solution Approach 1:
A ferrous metal trace is introduced as an intermediary between the magnet and the hall-effect sensor. The metal trace extends from beneath the magnet to the sensor location, conducting the magnetic field over distance. This allows the sensor to be positioned closer to the magnet while still receiving sufficient magnetic field strength, reducing the required PCB area while maintaining measurement precision.
Solution Approach 2:
The solution transitions from a direct perpendicular arrangement to a three-dimensional configuration where the metal trace provides a magnetic field conduction path through the vertical dimension (from beneath the magnet) to the sensor plane, enabling compact layout while maintaining field strength.
2Ease of manufacture
If the PCB size is reduced to lower cost, then manufacturing cost decreases, but the ability to detect multiple levers or accommodate sensors on different planes is compromised
Solution Approach 1:
The ferrous metal trace serves multiple functions: it conducts magnetic fields to enable sensor activation, allows compact PCB layout to reduce cost, and provides flexibility to detect multiple levers by routing traces to different locations. A single magnet can activate multiple sensors through separate metal trace paths, enabling multi-lever detection on a compact PCB.
Solution Approach 2:
The magnetic field conduction is segmented into separate metal trace paths, allowing individual routing to different sensor locations for detecting multiple levers. Each trace can be independently configured to reach its target sensor, providing versatility while maintaining compact overall PCB size.
3Measurement precision
If tight tolerances are maintained to ensure consistent sensor activation, then measurement accuracy improves, but manufacturing complexity and cost increase
Solution Approach 1:
The ferrous metal trace acts as a magnetic field conduit that is less sensitive to air gap variations. By providing a direct magnetic conduction path through the metal trace, the system becomes more tolerant of variations in the air gap between the magnet and sensor, reducing the need for tight manufacturing tolerances while maintaining activation consistency.
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 solution allows for a more versatile, cost-effective activation of hall-effect sensors, enabling smaller PCB designs, accurate detection of lever positions, and efficient use of space, while maintaining reliable ON/OFF signaling and potential for multiple activation points and polarity detection.
Implementation Method 1
a magnet secured to the at least one moveable component; a hall effect sensor remote from the magnet; and a metal trace operably coupled to the hall effect sensor and configured to be magnetized by the magnet
Implementation Method 2
Hall-effect sensors are becoming increasingly popular in latching systems. A hall-effect sensor is activated depending on the magnetic field strength that is reads
Implementation Method 3
a metal trace operably coupled to the hall effect sensor and configured to be magnetized by the magnet as the at least one moveable movable component rotates
Data Source
AI summary
A latch assembly, including: at least one moveable component rotationally mounted to the latch assembly; a magnet secured to the at least one moveable component; a hall effect sensor remote from the magnet; and a metal trace operably coupled to the hall effect sensor and configured to be magnetized by the magnet as the at least one moveable component rotates.