Position Detecting Device With Opposing Magnets
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Solution Overview
Problem
Existing position detecting devices face accuracy issues due to manufacturing tolerances causing displacement of magnetic components, leading to variations in output characteristics and reduced robustness.
Innovation Solution
A position detecting device is designed with first and second magnetic-flux generating members opposing each other across a virtual plane perpendicular to the movable member, and a magnetic detecting member positioned remotely to detect magnetic flux density, ensuring parallel magnetic field directions and increased magnetic field strength, thus enhancing robustness and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single magnet and magnetic detecting element are used with radial magnetic field, then the device structure is simple, but manufacturing tolerance causes displacement leading to large changes in output characteristics and decreased detection accuracy
Solution Approach 1:
The single magnet is divided into two separate magnets (first and second magnets), each generating magnetic fields in opposite directions. This segmentation creates a magnetic field configuration where the detecting element experiences more stable flux density variations despite positional displacement, thereby improving detection accuracy while maintaining relatively simple device structure
Solution Approach 2:
The patent creates a specific local magnetic field environment by positioning the detecting element in an area where magnetic field directions are parallel to the linear stroke direction. This localized field configuration ensures that even when the detecting element is displaced, the output characteristic variation is suppressed, improving measurement precision
2Force
If the magnetic detecting element is positioned closer to the magnet, then the magnetic field strength is higher, but the device becomes more sensitive to positional displacement due to manufacturing tolerance
Solution Approach 1:
Instead of having the detecting element experience radial magnetic fields directly from the magnets, the patent inverts the approach by having two magnets generate opposing fields that create a zone where the net field direction is parallel to the stroke direction. This inversion makes the system less sensitive to positional variations, improving reliability
Solution Approach 2:
The patent introduces an intermediate magnetic field configuration between the magnets and the detecting element. The opposing magnetic fields from the two magnets create a mediator field environment where the detecting element operates, reducing its sensitivity to position gap variations and improving robustness
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 configuration stabilizes output characteristics, increases signal-to-noise ratio, and improves detection accuracy by minimizing the impact of manufacturing tolerances and magnetic field interference, while also reducing manufacturing costs through simpler magnet geometry.
Implementation Method 1
a magnetic field of the first magnetic-flux generating member and a magnetic field of the second magnetic-flux generating member rebel against each other
Implementation Method 2
the magnetic detecting member outputs a signal depending on density of magnetic flux passing through the magnetic sensing surface
Data Source
AI summary
A first and a second magnet are provided on a movable member so as to oppose to each other across a virtual plane. Each magnet is magnetized in a direction perpendicular to the movable member, so that the same magnetic poles of the magnets are opposed to each other. A hall IC is provided at a position more remote from the movable member than the magnets so as to be movable on the virtual plane relative to the movable member. A Y-parallel area is formed in a space equally distanced from the first and the second magnets, in which magnetic fields of the first and the second magnet rebel against each other, so that directions of the magnetic fields are so made to be in parallel to a stroke direction of the movable member. Robustness for a position gap between the magnets and the hall IC is improved.