Magnetic Drum Pole Segmentation for Higher Encoder Resolution
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Solution Overview
Problem
The quality of output signals in magnetic encoders is compromised due to the formation of closed magnetic loops between adjacent magnetic poles, leading to weakened magnetic signals and reduced resolution, and the uniformity of magnetic signals is difficult to control in existing magnetic drums.
Innovation Solution
A magnetic drum design featuring a permanent magnetic ring body with inner and outer ring walls of opposite polarities, incorporating protrusions and recesses with the same polarity, which prevents the formation of closed magnetic loops and allows for precise control of magnetic field parameters through machining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of magnetic poles on the magnetic drum is increased to improve resolution, then the resolution of the magnetic encoder is improved, but the proportion of closed loops formed by magnetic lines of force between adjacent magnetic poles is greatly increased, causing the operating distance of the magnetic field to be reduced rapidly and the magnetic signals received by the magnetoresistive sensor to be weakened
Solution Approach 1:
The magnetic drum surface is segmented into protrusions and recesses, where protrusions serve as magnetic poles and recesses serve as non-magnetic areas. This segmentation prevents the formation of closed magnetic loops between adjacent magnetic poles by introducing magnetic field-free zones, thereby maintaining magnetic signal strength while allowing for increased number of magnetic poles to improve resolution.
2Manufacturing precision
If traditional magnetizing methods are used to control the uniformity of the magnetic signal source, then the magnetic drum can be manufactured, but the manufacturing process becomes very complicated and difficult to ensure uniformity
Solution Approach 1:
The patent replaces the complex magnetizing process with a mechanical machining process. By directly machining the protrusions and recesses on the magnetic drum surface, the uniformity of the magnetic signal source is controlled through precise mechanical dimensions rather than through complex magnetizing procedures, thereby simplifying the manufacturing process while ensuring uniformity.
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
Enhances the clarity and quality of magnetic signals received by the magnetoresistive sensor, improving the resolution and uniformity of output signals, enabling higher-quality magnetic encoders that meet specialized detection requirements.
Implementation Method 1
the permanent magnetic ring body includes an inner ring wall and an outer ring wall; the inner ring wall has a single first polarity, the outer ring wall is a single second polarity, and the first polarity is opposite to the second polarity
Implementation Method 2
a magnetic encoder is an angle or displacement measurement device mainly composed of a magnetoresistive sensor, a magnetic drum and a signal processing circuit
Data Source
AI summary
A magnetic drum and a magnetic encoder including same. The magnetic drum comprises a permanent magnet magnetic ring body (1); the permanent magnet magnetic ring body (1) comprises an inner ring wall (11) and an outer ring wall (12); the inner ring wall (11) has a single first polarity, the outer ring wall (12) has a single second polarity, and the first polarity is opposite to the second polarity; the inner ring wall (11) and the outer ring wall (12) are coaxially arranged; one of the inner ring wall (11) and the outer ring wall (12) is uniformly provided with a plurality of protrusions (13) around the axis of the permanent magnet magnetic ring body (1), and a recess (14) is formed between any two adjacent protrusions (13).