Magnetic Sensor Layout Using Soft Magnetic Bodies for Higher Sensitivity
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Solution Overview
Problem
Existing magnetic sensors are expensive and lack sufficient sensitivity due to the high processing costs and difficulty in achieving a sufficient difference in magnetic flux density, which limits their measurement accuracy.
Innovation Solution
A magnetic sensor design featuring magnets arranged in one direction with alternating polarities and soft magnetic bodies on their faces, allowing for reduced magnet volume and cost while enhancing sensitivity through controlled magnetic flux guidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the end surfaces of magnets are rounded to limit magnet volume, then cost is reduced, but processing costs increase due to the hardness of magnets
Solution Approach 1:
The invention divides the magnetic flux guidance function into two parts: the magnet itself and a separate yoke component. The yoke is a soft magnetic material that can be easily formed with rounded surfaces and protrusions/recesses, while the magnet maintains a simpler geometry that is easier and cheaper to manufacture. This segmentation allows each component to be optimized for its specific function and manufacturing constraints.
Solution Approach 2:
The yoke acts as an intermediary between the magnet and the magnetic field detecting element. It mediates the magnetic flux by providing a soft magnetic path that concentrates and directs the flux, enabling the magnet to have a simpler shape while still achieving the desired magnetic field distribution through the yoke's geometry.
2Shape
If protrusions and recesses are provided on a yoke to determine magnetic field shape, then magnetic field distribution is controlled, but sufficient change in magnetic flux density cannot be ensured
Solution Approach 1:
The invention applies local quality by creating concentrated magnetic flux paths through the yoke's protrusions and recesses that directly face the magnetic field detecting element. The yoke is designed with specific local geometries (protrusions and recesses) that concentrate magnetic flux in critical areas, ensuring sufficient variation in magnetic flux density at the detection point while maintaining overall magnetic field control.
Solution Approach 2:
The yoke is designed with asymmetric protrusions and recesses that create non-uniform magnetic flux distribution. This asymmetric geometry ensures that the magnetic flux density varies sufficiently as the magnet moves relative to the detecting element, providing the necessary signal variation for accurate measurement while maintaining controlled field distribution.
3Measurement precision
If magnets are arranged at intervals to improve measurement accuracy, then measurement precision improves, but the number of magnets increases leading to higher cost
Solution Approach 1:
The yoke serves as a magnetic flux mediator that enhances the effectiveness of each individual magnet. By providing concentrated flux paths through the yoke's geometry, each magnet generates a stronger and more defined magnetic field signal, improving measurement precision without requiring additional magnets. The yoke effectively amplifies the magnetic signal from fewer magnets.
Solution Approach 2:
The invention changes the magnetic circuit parameters by introducing the soft magnetic yoke material between the magnets and the detecting element. This parameter change (adding high permeability material) concentrates the magnetic flux and increases the magnetic flux density variation, thereby improving measurement accuracy with the same number of magnets or fewer magnets.
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 design achieves a balance between cost reduction and sensitivity improvement by optimizing magnetic flux density and reducing manufacturing complexity, resulting in a more affordable and accurate magnetic sensor.
Implementation Method 1
at least one soft magnetic body that is provided on the first face of at least one of the magnets
Implementation Method 2
soft magnetic body
Implementation Method 3
a plurality of magnets that are arranged at intervals in a first direction, the magnets moving in the first direction relative to the magnetic field detecting element
Implementation Method 4
The magnets are magnetized in a second direction that crosses the first direction such that the first faces of an adjacent pair of the magnets have different polarities
Data Source
AI summary
The present invention aims at providing A magnetic sensor that is less expensive and that is highly sensitive is provided.A magnetic sensor of the present invention has: a magnetic field detecting element; and a plurality of magnets that are arranged at intervals in a first direction, the magnets moving in the first direction relative to the magnetic field detecting element. The magnets have respective first faces that face the magnetic field detecting element. The magnets are magnetized in a second direction that crosses the first direction such that the first faces of an adjacent pair of the magnets have different polarities. The magnetic sensor further includes at least one soft magnetic body that is provided on the first face of at least one of the magnets.