Lever Neutral Position Detection Using Axial Magnet and Hall Sensor
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Solution Overview
Problem
Existing solutions for detecting the neutral position of a control lever in motor vehicle gearboxes are not straightforward or effective, particularly in systems with STOP AND START systems, as they fail to provide accurate and secure detection of the neutral point, which is crucial for cutting off power supply to the drive motor when the vehicle is stopped.
Innovation Solution
A device comprising an axially magnetized cylindrical magnet positioned in the hinge and ball joint of the lever and a unidirectional Hall-effect probe sensor mounted on a fixed portion, ensuring maximum magnetic field coverage at the neutral point, allowing for precise detection of the lever's neutral position and separation from gear selection movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Hall effect sensor is mounted opposite a magnet on the lever to detect various positions along three perpendicular axes, then accurate information about lever positions and movements is provided, but the device complexity increases and the neutral point detection becomes less straightforward
Solution Approach 1:
The invention extracts the neutral point detection function from the multi-axis position detection system. By using a unidirectional Hall-effect probe oriented perpendicular to the gear selection axis and positioned at the neutral point, the system separates neutral detection from general position tracking, simplifying the overall detection architecture while maintaining accuracy
Solution Approach 2:
The invention applies local quality by positioning the magnet and unidirectional sensor specifically at the neutral point location rather than using a comprehensive multi-axis detection system. The magnet is axially magnetized with its magnetization axis perpendicular to the gear selection axis, creating a localized magnetic field that only affects the neutral point detection, thereby reducing overall system complexity
2Measurement precision
If a unidirectional Hall-effect probe is used with maximum magnetic field coverage at the neutral point, then measurement accuracy is improved, but the device complexity increases
Solution Approach 1:
The invention changes the magnetic field parameters by using axial magnetization perpendicular to the gear selection axis, which creates a magnetic field distribution optimized for neutral point detection. This parameter change allows a single unidirectional sensor to achieve maximum measurement accuracy at the neutral point without requiring complex multi-sensor arrangements
3Reliability
If the sensor is positioned opposite the magnet at the neutral point, then neutral position detection is simplified and made more reliable, but the separation from gear selection movements becomes more difficult
Solution Approach 1:
The invention segments the detection function by using a unidirectional sensor that only responds to magnetic field changes in one direction (perpendicular to the gear selection axis). This segmentation isolates neutral point detection from gear selection movements, as the sensor ignores magnetic field variations caused by gear shifting while remaining sensitive to neutral point position
Solution Approach 2:
The invention introduces asymmetry by orienting the magnet's magnetization axis perpendicular to the gear selection axis rather than parallel to it. This asymmetric configuration creates a magnetic field pattern where the neutral point produces a distinct signal while gear selection movements produce no signal in the sensor's measurement direction, thereby simplifying detection while maintaining reliability
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 enables accurate and secure detection of the neutral position, allowing for reliable power cut-off in STOP AND START systems, improving measurement accuracy and ensuring the neutral point can be detected with a single unidirectional probe.
Implementation Method 1
a unidirectional Hall-effect probe sensor mounted on a fixed portion
Data Source
AI summary
The lever is mounted such as to be capable of moving relative to a detector suitable for detecting lever movements and for sending electrical signals to a processing unit. The detector comprises an axially magnetized cylindrical magnet positioned according to the axis of rotation and selection of the lever corresponding to the selection of gears, and a sensor arranged opposite the magnet, such that the signal is independent of the angular position of the lever about the gear-selection axis.