Magnetic Transmission Park Position Sensor with Flux Concentrator
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Solution Overview
Problem
Existing transmission position sensors face challenges in accurately determining whether a transmission is in the park or out-of-park position, leading to potential false alarms and reduced reliability due to noise interference and magnetic field fluctuations.
Innovation Solution
A transmission range selection sensor system utilizing Hall Effect sensors with magnetic flux concentrators to enhance the detection of the transmission position, ensuring accurate determination of the transmission range by focusing the magnetic field towards the sensors, thereby improving reliability and robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic sensors are used to detect transmission position, then the position detection function is achieved, but noise interference and magnetic field fluctuations reduce measurement accuracy
Solution Approach 1:
A magnetic flux concentrator is introduced as an intermediary component between the magnet and the magnetic sensors. This concentrator focuses and channels the magnetic field lines, creating a more defined and stable magnetic flux path that reaches the sensors. By using this intermediary structure, the system achieves better signal-to-noise ratio and improved position detection accuracy despite the presence of environmental noise and magnetic field fluctuations.
2Reliability
If a single magnetic sensor is used, then the device complexity is low, but the reliability of position determination is reduced
Solution Approach 1:
The position detection function is segmented into multiple independent sensing points along the axial direction. By placing multiple magnetic sensors at different axial positions, each sensor provides independent measurement data about the magnet's position. This segmentation approach increases reliability because the system can cross-validate readings from multiple sensors and determine position more confidently, reducing false alarms while maintaining a relatively simple overall device structure.
3Measurement precision
If magnetic flux concentrators are added to focus the magnetic field, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The magnetic flux concentrator is constructed using composite material structures that combine ferromagnetic materials with appropriate geometric configurations. This allows the concentrator to effectively focus magnetic flux while maintaining a compact and manufacturable form factor. The use of composite approaches in the concentrator design achieves high measurement precision without excessively increasing device complexity, as the concentrator can be integrated into the existing sensor housing or mounting structure.
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
The system provides enhanced reliability and robustness in distinguishing between in-park and out-of-park positions, reducing false alarms and maintaining accuracy even under noise interference and temperature variations, ensuring proper vehicle function control.
Implementation Method 1
A magnet is attached to and moveable with the magnet carrier. The magnet generates a magnetic field.
Implementation Method 2
A first magnetic sensor is attached to the housing... A second magnetic sensor is attached to the housing... The position of the magnet carrier along the central axis is determinable from a sensed magnetic flux from the first magnet sensor, and a sensed magnetic flux from the second magnetic sensor.
Implementation Method 3
at least one magnetic flux concentrator is attached to one of the magnet carrier or the housing... The magnetic flux concentrator is a ferrous material... focusing the magnetic field towards the sensors
Data Source
AI summary
A transmission range selection sensor includes a housing defining a bore extending along a central axis. A piston is slideably disposed within the bore. A magnet carrier is attached to and moveable with the piston. A magnet is supported by and moveable with the magnet carrier. A first magnetic sensor and a second magnetic sensor are supported by the housing and are spaced from each other along the central axis. A position of the magnet carrier along the central axis is determinable from a sensed magnetic flux from the first and second magnetic sensors. The sensor includes at least one magnetic flux concentrator attached to one of the magnet carrier or the housing. The flux concentrator is operable to concentrate the magnetic flux toward at least one of the first magnetic sensor or the second magnetic sensor depending upon a position of the magnet along the central axis.