Transmission Shift Rail Hall Sensors for Magnetic Interference Detection
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Solution Overview
Problem
Automated transmission systems face interference from external magnetic fields, which can corrupt sensor signals and disrupt gear shifting, particularly in environments with strong magnetic interference like factories or near heavy-current cables or lifting magnets, where existing shielding methods are complex and inefficient.
Innovation Solution
A sensor arrangement with 3D Hall sensors and permanently magnetized signal transmitters aligned identically in a horizontal plane, allowing for detection of external magnetic interference by evaluating signal changes across multiple sensors, distinguishing between interference and gear shifting operations based on signal profiles and tolerance ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional shielding methods are used to protect sensors from external magnetic fields, then sensor protection is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The sensor arrangement uses itself to detect magnetic interference. The 3D Hall sensors monitor the magnetic field environment and identify interference patterns, allowing the system to self-diagnose and self-correct without external shielding structures. The sensors serve dual purposes: normal displacement detection and magnetic interference detection.
Solution Approach 2:
The system implements feedback by continuously monitoring sensor signals for patterns indicative of magnetic interference. When interference is detected through signal analysis (identifying characteristic patterns in Hall sensor outputs), the system can trigger corrective actions such as switching to alternative measurement methods or alerting operators, creating a closed-loop protection mechanism.
2Measurement precision
If additional magnetic field detection equipment is added, then interference detection capability is improved, but device complexity and cost increase
Solution Approach 1:
The existing 3D Hall sensors perform multiple functions: they detect both the normal operational parameters (shift rail position) and magnetic interference conditions. By analyzing the full three-dimensional magnetic field data already being collected for position sensing, the system can identify interference patterns without requiring separate detection sensors.
Solution Approach 2:
The sensor system monitors its own operating environment using its existing capabilities. The Hall sensors' primary function of detecting magnetic field strength for position measurement also serves as the basis for detecting external magnetic interference, eliminating the need for dedicated interference detection equipment.
3Measurement precision
If signal receivers are arranged in a horizontal plane with identical magnetic pole alignment, then detection accuracy is improved, but susceptibility to external magnetic interference increases
Solution Approach 1:
The system uses feedback from all three spatial components of the 3D Hall sensors to detect and compensate for magnetic interference. By continuously monitoring the magnetic field vectors in x, y, and z directions, the system can identify when external interference distorts the expected field pattern and adjust measurements accordingly.
Solution Approach 2:
The patent converts the vulnerability to magnetic interference into a detection opportunity. The same magnetic field components that cause interference also provide the signal for detecting interference presence. By analyzing deviations in the three-dimensional magnetic field vector from expected patterns, the system identifies and flags interference conditions, turning a harmful effect into a useful diagnostic signal.
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
Enables effective detection and mitigation of external magnetic interference without additional equipment, ensuring accurate gear position sensing and preventing gear shift corruption, allowing the system to operate reliably in interference-prone environments.
Implementation Method 1
the signal receivers are each in the form of a 3D Hall sensor
Data Source
AI summary
A sensor arrangement (46) for an automated transmission includes multiple axially parallel shift rails (4, 14, 24, 34) being axially displaceable by associated shift actuators (8, 18, 28, 38). The sensor arrangement (46) has multiple displacement sensors (48, 56, 64, 72) made up of a signal transmitter (50, 58, 66, 74) attached to a shift rail and a signal receiver (52, 60, 68, 76) fixedly arranged on a housing. The signal transmitters are in the form of a permanent magnet, and the signal receivers are in the form of a 3D Hall sensor. To detect an external magnetic interference field, which can corrupt the sensor signals from the displacement sensors (48, 56, 64, 72), the signal transmitters (50, 58, 66, 74) have identical axial alignments of their magnetic poles, and the signal receivers (52, 60, 68, 76) are in a common plane (80) that is horizontal in their installation position.