Magnetic Sensor Unit with Yoke Convex Portion for Accurate Field Detection
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Solution Overview
Problem
Conventional magnetic sensor units face challenges in accurately detecting changes in magnetic fields due to decreased magnetic flux density and external magnetic field interference, as well as difficulties in accurately positioning magnets with respect to a yoke.
Innovation Solution
A magnetic sensor unit is designed with a yoke having a convex portion between two magnets, featuring abutting portions that enhance magnetic flux density and facilitate precise magnet positioning, allowing for improved detection accuracy and expanded detection range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two magnets are disposed apart from each other in the circumferential direction of the yoke, then the magnetic sensor can detect a wider range of displacement, but the magnetic flux density decreases and the detection accuracy deteriorates
Solution Approach 1:
A magnetic body is introduced as an intermediary between the two magnets to concentrate and guide magnetic flux. The magnetic body includes a first magnetic path connecting the N-pole of the first magnet to the S-pole of the second magnet, and a second magnetic path connecting the S-pole of the first magnet to the N-pole of the second magnet. This intermediary structure maintains high magnetic flux density in the detection region even when magnets are spaced apart, thereby preserving detection accuracy while enabling wider detection range.
2Area of stationary object
If two magnets are disposed apart from each other, then more space is available for sensor placement, but the magnetic flux density is likely to decrease and be affected by external magnetic fields
Solution Approach 1:
The magnetic body acts as a mediator that confines and directs magnetic flux between the two magnets. By providing dedicated magnetic paths (first magnetic path and second magnetic path) that connect corresponding poles of the magnets, the magnetic body creates a controlled magnetic environment that isolates the magnetic field from external interference while maintaining sufficient magnetic flux density in the detection region.
3Device complexity
If magnets are fixed directly to the yoke, then the structure is simple, but it is difficult to accurately position each magnet with respect to the yoke
Solution Approach 1:
The magnetic body serves as an intermediary component between the magnets and the yoke, providing dedicated positioning surfaces and structures. The magnetic body includes specific geometric features such as the first magnetic path and second magnetic path that are designed to accurately position the magnets relative to each other and to the yoke. This intermediary structure enables precise magnet positioning while maintaining overall structural simplicity.
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 configuration enables accurate detection of magnetic field changes and precise magnet positioning, enhancing detection accuracy and reducing external interference, thereby improving the magnetic sensor unit's performance.
Implementation Method 1
a magnetic sensor that is fixed to the first member and is configured to detect a change of a magnetic field formed by the at least two magnets
Data Source
AI summary
A magnetic sensor unit capable of accurately detecting a change of a magnetic field by a magnetic sensor and accurately positioning each magnet with respect to a yoke includes a yoke fixed to a rotor relatively displaced with respect to a base plate, two magnets fixed to the yoke and disposed apart from each other in a relative displacement direction of the rotor, and a magnetic sensor fixed to the base plate and detecting a change of a magnetic field formed by the two magnets. The yoke has a convex portion protruding between the two magnets. The convex portion includes abutting portions on which the two magnets abut.