Stroke Sensor Magnet Layout for Stable Field Detection
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Solution Overview
Problem
The existing stroke sensors with magnets of the same shape and dimensions face difficulties in achieving the required magnetic field intensity due to sinusoidal magnetic field distribution, especially when the moving range or sensor position is limited, making it challenging to obtain sufficient magnetic field intensity for accurate measurement.
Innovation Solution
A stroke sensor design featuring two magnets with different polarities and dimensions, where the distance between them is fixed, allowing for adjustable magnetic field distribution without altering their positions, with a magnetic field detecting sensor positioned to detect the magnetic field generated by both magnets, ensuring optimal magnetic field intensity is maintained across the measurement range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnets of the same shape and dimensions are used, then the structure is simple and manufacturing is easy, but the magnetic field intensity at the middle point between adjacent magnets becomes zero, making it difficult to obtain the required magnetic field intensity for accurate detection
Solution Approach 1:
The patent applies asymmetry by configuring magnets with different shapes and dimensions rather than using identical magnets. Specifically, the first magnet has different dimensional characteristics than the second magnet, creating an asymmetric magnetic field distribution that eliminates the zero-intensity point problem while maintaining structural feasibility
Solution Approach 2:
The patent implements local quality by making each magnet have different local characteristics (shapes and dimensions) tailored to their specific positions and functions. The first magnet and second magnet have different geometries optimized for their respective roles in generating the magnetic field, allowing each location to contribute differently to the overall field distribution
2Measurement precision
If the moving range of magnets is limited or the position of the magnetic field detecting sensor is limited, then the device structure is compact, but the magnetic field intensity required for accurate detection cannot be obtained due to sinusoidal magnetic field distribution
Solution Approach 1:
The asymmetric magnet configuration changes the magnetic field distribution pattern from sinusoidal to non-sinusoidal, eliminating the zero-crossing points that limit detection accuracy. This allows the magnetic field detecting sensor to maintain accurate measurements even when positioned at limited locations or when magnet movement range is constrained
Solution Approach 2:
The patent changes the parameters of the magnets (shapes and dimensions) to fundamentally alter the magnetic field distribution characteristics. By varying the geometrical parameters of the magnets, the system achieves a magnetic field profile that maintains sufficient intensity across the limited sensor position range and restricted magnet movement range
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 enables adjustment of the magnetic field distribution without moving the magnets, ensuring reliable magnetic field intensity detection, reducing the minimum moving distance required for the magnets to reach a predetermined threshold, thus enhancing the accuracy and reliability of the measurement.
Implementation Method 1
The moving distance of the magnet is detected by the magnetic field detecting sensor by sensing change in the intensity of a magnetic field that is generated by the magnet
Data Source
AI summary
A stroke sensor that allows adjustment of the magnetic field distribution without changing the positions of the magnets is provided. Stroke sensor 1 has magnets 2A, 2B, and sensor 3A that detects a magnetic field that is generated by magnets 2A, 2B. Magnets 2A, 2B are movable relative to sensor 3A in first direction X. Magnet 2A has surface 5A that faces sensor 3A in second direction Z, magnet 2B has surface 5B that faces sensor 3A in second direction Z, and surface 5A and surface 5B have different polarities. A position in first direction X at which magnetic field intensity in second direction Z is zero is positioned between reference axis RA and magnet 2B. Reference axis RA is parallel to second direction Z and passes through middle point MP of minimum section S that includes magnets 2A, 2B in first direction X.