Rotational Displacement Detection Using Axial Magnetization
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Solution Overview
Problem
Existing relative rotational angular displacement detection devices require high dimensional and assembly accuracy, increasing manufacturing and assembly costs, to achieve precise magnetic flux change detection between coaxially arranged rotatable members.
Innovation Solution
A relative rotational angular displacement detection device comprising a permanent magnet with axial magnetization, a magnetic flux guiding ring with protruding portions, and a magnetic detection unit, which simplifies the structure and assembly while enhancing detection accuracy by using a magnetic sensor to detect magnetic fluxes in the magnetization direction of the annular plane portion of the ring body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional magnetic flux detection is used with multiple yoke rings and magnetic flux collector rings, then detection precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts and eliminates unnecessary components from the conventional detection device. Specifically, it removes the multiple yoke rings and magnetic flux collector rings, retaining only the essential permanent magnet and magnetic sensor. This simplification maintains detection functionality while reducing structural complexity and manufacturing cost.
Solution Approach 2:
The patent inverts the conventional detection approach by changing the magnetization direction from radial to axial direction. This inversion allows the magnetic flux to pass directly through the annular plane portion of the rotatable member to the magnetic sensor, eliminating the need for complex yoke ring structures while maintaining detection precision.
2Measurement precision
If high dimensional accuracy is required for yoke rings and magnetic flux collector rings, then detection accuracy is improved, but manufacturing precision requirements and cost increase
Solution Approach 1:
The patent removes the yoke rings and magnetic flux collector rings that require high dimensional accuracy, replacing them with a simplified structure consisting of a permanent magnet with axial magnetization and a magnetic sensor. This eliminates the manufacturing precision requirements associated with the removed components.
Solution Approach 2:
The patent changes the magnetization parameter from radial direction to axial direction. This parameter change fundamentally alters the magnetic flux path, allowing direct detection through the annular plane portion without requiring precisely positioned yoke rings and collector rings, thereby reducing manufacturing precision requirements.
3Measurement precision
If multiple components (yoke rings, magnetic flux collector rings, magnetic sensors) are assembled, then detection functionality is achieved, but assembly complexity and time increase
Solution Approach 1:
The patent extracts and eliminates the yoke rings and magnetic flux collector rings from the assembly, reducing the number of components that need to be assembled. Only the permanent magnet and magnetic sensor remain, significantly reducing assembly complexity and time.
Solution Approach 2:
The patent merges the functions of the permanent magnet and magnetic sensor into a simpler configuration where the magnetic sensor directly detects flux changes from the axially magnetized permanent magnet through the annular plane portion. This merging eliminates the need for intermediate yoke and collector ring components, reducing assembly steps.
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 solution allows for high-precision detection of relative rotational angular displacement with reduced manufacturing and assembly complexity, improving detection accuracy and cost-effectiveness.
Implementation Method 1
a magnetic flux guiding ring including an annular ring body attached to the other of the pair of rotatable members and arranged coaxially with the axis of rotation
Implementation Method 2
a magnetic detection unit for detecting magnetic fluxes of the ring body of the magnetic flux guiding ring magnetized depending on a relative position of each protruding portion of the magnetic flux guiding ring and each magnetic pole of the permanent magnet
Data Source
AI summary
A relative rotational angular displacement detection device includes a pair of rotatable members rotatable relative to each other in a circumferential direction. A permanent magnet is attached to one of the rotatable members and includes magnetic poles magnetized in an axial direction of the axis of rotation and arranged to alternate in polarity in the circumferential direction. A magnetic flux guiding ring includes an annular ring body attached to the other of the rotatable members and is arranged coaxially with the axis of rotation, and a plurality of protruding portions each having a circumferential width smaller than the circumferential width of the magnetic pole. A magnetic detection unit is configured to detect magnetic fluxes of the ring body of the magnetic flux guiding ring. The magnetic flux guiding ring is magnetized depending on the positions of the protruding portions relative to the positions of the magnetic poles.