Magnetic Encoder Track Design for Interference Management

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Solution Overview

Problem

Magnetic encoders with plural rows of tracks face challenges in reducing size and increasing detection sensitivity due to magnetic interference, which complicates construction and increases production costs, while maintaining accurate signal detection and a desired air gap.

Innovation Solution

The magnetic encoder configuration includes plural rows of tracks with alternating N and S poles, arranged adjacent to each other, allowing for equal pitch signal detection through magnetic interference, eliminating the need for additional space or magnetic materials, and ensuring a suitable air gap for accurate sensor positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the space between plural magnetic tracks is reduced to decrease device size, then the device becomes more compact, but magnetic interference between tracks increases reducing detection sensitivity

Engineering Contradiction:
Improvedevice sizeVSAvoiddetection sensitivity
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent applies the principle of converting harmful magnetic interference into a beneficial effect by intentionally designing the magnetic tracks to generate interference patterns that cancel each other out. By arranging tracks with specific magnetic pole configurations, the interference between adjacent tracks is transformed from a detrimental factor into a mechanism that maintains signal accuracy while allowing reduced track spacing for compact device size.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the magnetic field parameters by varying the magnetic pole configurations, densities, and orientations of adjacent tracks. By carefully controlling these parameters, the magnetic interference between tracks is optimized to maintain detection sensitivity even when tracks are positioned closer together, thus reducing overall device size.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If magnetic materials are interposed between magnetic tracks to reduce magnetic interference, then detection sensitivity improves, but construction complexity and production cost increase

Engineering Contradiction:
Improvedetection sensitivityVSAvoidconstruction complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the need for additional magnetic separator materials by incorporating interference compensation directly into the magnetic track structure itself. The magnetic tracks are designed with specific pole configurations that inherently cancel interference, eliminating the requirement for separate magnetic shielding materials and simplifying the overall construction.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the function of magnetic track generation with the function of interference compensation into a single integrated structure. By combining the magnetic pole configurations of adjacent tracks to create mutually compensating interference patterns, the design eliminates the need for separate magnetic shielding layers, thereby reducing construction complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If magnetic materials are interposed between magnetic tracks to reduce magnetic interference, then detection sensitivity improves, but production cost increases

Engineering Contradiction:
Improvedetection sensitivityVSAvoidproduction cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent extracts the need for additional magnetic separator materials by incorporating interference compensation directly into the magnetic track structure itself. The magnetic tracks are designed with specific pole configurations that inherently cancel interference, eliminating the requirement for separate magnetic shielding materials and simplifying the overall construction.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the function of magnetic track generation with the function of interference compensation into a single integrated structure. By combining the magnetic pole configurations of adjacent tracks to create mutually compensating interference patterns, the design eliminates the need for separate magnetic shielding layers, thereby reducing construction complexity.

Inventive Principle:
Principle #5Merging (Combining)

4Reliability

If air gap between magnetic encoder and sensors is increased to prevent contact, then reliability improves, but magnetic field strength at sensors decreases

Engineering Contradiction:
Improvecontact preventionVSAvoidmagnetic field strength
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The patent changes the magnetic field parameters by optimizing the pole configurations, densities, and orientations of the magnetic tracks. These parameter adjustments create more efficient magnetic field distributions that maintain sufficient field strength at the sensor location even when a larger air gap is used for reliability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent performs preliminary optimization of the magnetic track design during the manufacturing phase, configuring the pole patterns and magnetic material distribution in advance to compensate for the air gap. This preliminary action ensures that when the device is assembled with adequate clearance for reliability, the magnetic field strength at the sensors remains sufficient for accurate detection.

Inventive Principle:
Principle #10Preliminary action

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 simplifies the construction of magnetic encoders, reduces production costs, and enables precise detection of rotation signals while maintaining a compact size and desired air gap, enhancing the reliability of magnetic field strength and reducing errors caused by interference.

Implementation Method 1

plural rows of magnetic encoder tracks that are arranged adjacent to each other and are formed integrally with the magnetic encoder, at least one magnetic encoder track of the magnetic encoder tracks including a magnetic pattern having N poles and S poles arranged in alternate fashion magnetized thereto to generate signals of equal pitch

Methodology Applied
Scientific EffectMagnetic field generation: Magnetic Field

Implementation Method 2

sensors that read magnetic signals of the respective magnetic encoder tracks

Methodology Applied
Scientific EffectMagnetic field detection: Magnetic Field

Data Source

PatentEP2579002B1Magnetic encoder
Publication Date: 2017.03.29 NTN CORP
  • EP2579002B1 patent drawingFigure 1A~1B
  • EP2579002B1 patent drawingFigure 2(A)~2(B)
  • EP2579002B1 patent drawingFigure 3A~3B

AI summary

Provided is a magnetic encoder which includes plural rows of magnetic encoder tracks. One magnetic encoder track of the magnetic encoder tracks includes magnetic pattern magnetized thereto to generate signals of equal pitch for detection of rotation. The magnetized magnetic pattern includes N poles and S poles arranged in alternate fashion. The magnetic encoder is configured to be employed spaced through an air gap from sensors that read magnetic signals of the respective magnetic encoder tracks. The magnetic encoder track is configured such that the magnetic pattern thereof acting on position of the corresponding sensor is, under the interference of magnetism of the plural rows of magnetic encoder tracks, detected by the corresponding sensor as an equal pitch magnetic pattern.