Position Sensor with Opposing Magnets for Shift Lever Backlash
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Solution Overview
Problem
Existing position sensors for shift levers in ultra-compact shift-by-wire systems face challenges in accurately detecting small operation angles due to backlash from play in the shift lever, which affects detection accuracy.
Innovation Solution
A position sensor design featuring two opposing magnets with concave shapes generating a parallel magnetic field at the rotation center of a support structure, with a magnetic detector positioned between them, enhances detection accuracy by minimizing the impact of backlash and allowing for redundancy by positioning detectors above and below a substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional position sensor with a single magnet is used, then the device structure is simple, but the detection accuracy is reduced due to backlash affecting the magnetic field inclination
Solution Approach 1:
The single magnet is segmented into two opposing magnets, each generating a magnetic field component. The combination of these two magnets creates a parallel magnetic field at the rotation center that is insensitive to backlash, thereby improving detection accuracy while maintaining reasonable structural complexity
Solution Approach 2:
The magnetic detector is positioned as an intermediary between the two opposing magnets, detecting the parallel magnetic field generated at the rotation center. This intermediary positioning allows the system to measure the desired magnetic field while avoiding the harmful effects of backlash
2Reliability
If the magnetic field range is limited, then the magnet structure is compact, but the position sensor is affected by backlash when magnetic detectors are located above and below the substrate
Solution Approach 1:
The magnetic field geometry is transformed by positioning two magnets opposing each other, creating a parallel magnetic field that extends across multiple dimensions (above and below the substrate). This dimensional expansion ensures the magnetic field remains parallel and unaffected by backlash across the extended range
3Measurement precision
If the operation angle is extremely small (10° or less), then the shift lever is ultra-compact, but the detection of shift lever inclination becomes difficult due to backlash
Solution Approach 1:
The magnetic field quality is optimized locally at the rotation center by positioning two magnets opposing each other. This creates a parallel magnetic field in the specific local region where the magnetic detector is positioned, ensuring high-resolution inclination detection for small operation angles without being affected by backlash
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 improves detection accuracy and robustness by maintaining a parallel magnetic field over a wide range, effectively distinguishing shift lever inclination from backlash and providing redundancy through concentrated detection elements.
Implementation Method 1
a magnet that generates a magnetic field and a magnetic detector that is positioned opposing the magnet to detect an inclination of the magnetic field caused by the magnet
Data Source
AI summary
A position sensor includes a magnet that generates a magnetic field, and a magnetic detector that is positioned opposing the magnet to detect an inclination of the magnetic field caused by the magnet. The magnet and the magnetic detector move relative to each other when an operation member is automatically or manually operated. The position sensor detects an operation position of the operation member based on a detection signal of the magnetic detector. The magnet includes two magnets positioned to oppose each other to generate the magnetic field as a parallel magnetic field at a rotation center of a support structure that forms operation axes of the operation member in multiple directions. The magnetic detector is arranged between the two magnets positioned opposing each other.