Gear Shaft Position Sensing With Single-Magnet Reverse Detection
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Solution Overview
Problem
Current position sensing systems for gear shafts in vehicles require two sets of magnets and circuitry to detect neutral and reverse gear positions, leading to high manufacturing costs and increased failure rates.
Innovation Solution
A single magnet is partitioned into a first length region and a second length region, with the second region further divided into portions of different polarities or without magnetization, allowing a Hall sensing unit to differentiate between forward and reverse gear positions by comparing inductive electrical signals against pre-determined references, thus eliminating the need for separate sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two separate position sensing systems are used to detect neutral and reverse gear positions, then the detection accuracy is improved, but the manufacturing cost increases and the failure rate increases
Solution Approach 1:
The patent combines two separate position sensing systems into a single integrated sensing system that uses one magnet and one Hall sensing unit to detect multiple gear positions (neutral, reverse, and forward positions) through a unified magnetic field detection mechanism
Solution Approach 2:
The single Hall sensing unit is designed to perform multiple detection functions by sensing different magnetic field states generated by the magnet at different gear positions, enabling one component to replace what traditionally required two separate systems
2Reliability
If two sets of magnets and circuitry elements are used, then the reliability is improved through redundancy, but the manufacturing cost increases
Solution Approach 1:
The patent merges two separate magnet-circuitry assemblies into a single magnet with a unified circuitry system, reducing the total number of components while maintaining detection reliability through the multi-functional design of the Hall sensing unit
3Adaptability or versatility
If two sets of circuitry elements and mechanical elements are used, then the detection coverage is improved, but the failure rate increases
Solution Approach 1:
The Hall sensing unit is designed as a universal detector that can identify multiple gear positions (neutral, reverse, forward) by interpreting different magnetic field configurations, reducing the number of mechanical elements and circuitry while expanding detection coverage through software/firmware-based position identification
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 reduces manufacturing costs and failure rates by enabling reliable detection of neutral and reverse gear positions using a single set of magnetic and circuitry components, while maintaining compatibility with existing mechanical designs.
Implementation Method 1
a sensing unit arranged to sense a magnetic field change of the sensing magnet when the sensing magnet moves with the gear shaft and to generate a corresponding inductive electrical signal
Data Source
Figure 1
Figure 2a~2b
Figure 2c~2d
AI summary
The present disclosure discloses a sensing system for sensing a position of a gear shaft. In the present disclosure, a magnet apparatus is provided on the gear shaft, where the magnet apparatus includes, along a rectilinear motion direction, a first length region magnet and a second length region magnet, the second length region magnet including a first portion and a second portion, a magnetic field of the second portion of the second length region magnet corresponding to a reverse gear position being different from that of the first length region magnet and that of the first portion of the second length region magnet. An actually induced electrical signal generated by sensing the motion of the magnet apparatus is different from a reference inductive electrical signal of a corresponding position of a reference magnet. The processing unit compares the inductive electrical signal generated by sensing the motion of the magnet apparatus against a simulated inductive electrical signal and determines whether the gear shaft is at a reverse gear position or a forward gear position based on a difference from the comparison.