Rotary Encoder Trigger Signal Generation Using Wiegand Effect

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Solution Overview

Problem

Existing rotary encoders are complex and expensive to manufacture, limiting their cost-effectiveness and ability to function independently without an external power source.

Innovation Solution

A rotary encoder design featuring a stator and rotor with specific magnetic sensor configurations, including pulse wires and magnets, that allow for energy self-sufficiency and cost-effective production by generating trigger signals from specific magnetic interactions, enabling accurate angular position measurement even without external power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional magnetic scanning principles with multiple magnetic pole segments and flux concentrators are used, then the rotary encoder can determine angular position, but the manufacturing complexity and cost increase significantly

Engineering Contradiction:
Improveangular position determinationVSAvoidmanufacturing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the complex flux concentrators and multiple magnetic pole segments from the traditional design. Instead, it uses a single magnet with simple polarity segments on the rotor and corresponding sensors on the stator, removing unnecessary components while maintaining the essential magnetic field detection function for angular position measurement.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent inverts the traditional approach by placing the magnetic field source (magnet with polarity segments) on the rotor and the detection elements (sensors) on the stator, rather than having multiple magnets and flux concentrators. This inversion simplifies the overall structure and reduces manufacturing complexity while achieving the same measurement function.

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If the rotary encoder is equipped with multiturn gears and magnetic measuring principles for emergency operation, then it can count revolutions without external power, but the device complexity and cost increase

Engineering Contradiction:
Improveemergency operation capabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes the primary magnetic sensing system serve dual functions: it accurately measures angular position during normal powered operation and simultaneously counts revolutions during emergency unpowered operation. The same magnets and sensors perform both functions, eliminating the need for separate multiturn gear mechanisms.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the angular position measurement function and the revolution counting function into a single integrated magnetic sensing system. The magnets with polarity segments and the sensors work together to provide both precise angular measurement and revolution tallying, combining what were previously separate functions into one unified system.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If multiple magnetic pole segments and flux concentrators are arranged over the shaft circumference, then angular position can be determined, but the manufacturing cost and complexity increase

Engineering Contradiction:
Improveangular position measurementVSAvoidmanufacturing ease
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent applies segmentation to the magnet itself by creating distinct polarity segments (N and S poles) on the rotor magnet rather than using multiple separate magnets or complex flux concentrator arrangements. This segmentation of the magnetic field source simplifies the overall structure while maintaining the ability to determine angular position through the varying magnetic field patterns detected by the sensors.

Inventive Principle:
Principle #1Segmentation

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 enables cost-effective production and operation of rotary encoders that can accurately measure angular position independently, reducing manufacturing complexity and operational reliance on external power sources.

Implementation Method 1

A magnetically sensitive unipolar element, for example a pulse wire or a Hall element, can be used as the trigger sensor

Methodology Applied
Scientific EffectWiegand effect: Wiegand Effect

Implementation Method 2

The magnetic sensors detect the respective magnetic field of the first magnet and the third magnet when the two components rotate relative to each other by at least one full revolution

Methodology Applied
Scientific EffectMagnetic field detection: Magnetic Field

Data Source

PatentEP2023093B1Rotary encoder and method for its operation
Publication Date: 2016.02.10 DR JOHANNES HEIDENHAIN GMBH
  • EP2023093B1 patent drawingFigure 1
  • EP2023093B1 patent drawingFigure 2a
  • EP2023093B1 patent drawingFigure 2b

AI summary

The invention relates to a rotary encoder and a method for its operation, comprising two component groups (1, 2) arranged to be rotatable relative to each other about an axis (A), wherein the first component group (1) comprises a trigger sensor (1.1) and several magnetic sensors (1.3, 1.4). The second component group comprises a first magnet (2.1, 2.4), a second magnet (2.2, 2.5), and a third magnet (2.3, 2.6). The component groups (1, 2) are configured such that the magnetic field of the first magnet (2.1, 2.4) and the third magnet (2.3, 2.6) can be detected by the magnetic sensors (1.3, 1.4) during one full rotation. The second magnet (2.2, 2.5) and the third magnet (2.3, 2.6) can generate a trigger signal through the trigger sensor (1.1), while the first magnet (2.1, 2.4) prevents the trigger sensor (1.1) from generating a trigger signal.