Absolute Rotary Encoder Flux Coupling Winding Segmentation

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Solution Overview

Problem

Downsizing absolute rotary encoders leads to increased displacement influence and reduced measurement accuracy due to signal intensity loss and displacement errors.

Innovation Solution

The design includes a rotor with flux coupling windings having linear arc portions of different radii arranged alternately in a ring shape, and a stator with transmitting windings positioned outward of the innermost receiving windings, allowing for efficient signal transmission and reduced displacement impact, enabling accurate measurements in a compact form.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the absolute rotary encoder is downsized, then the device size is reduced, but the measurement accuracy deteriorates due to increased displacement influence and signal intensity loss

Engineering Contradiction:
Improveencoder sizeVSAvoidmeasurement accuracy
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

The rotor track is divided into multiple linear arc portions with alternating first and second radii, creating a segmented flux coupling winding pattern. This segmentation maintains signal intensity in downsized encoders by optimizing the flux coupling path geometry, allowing accurate measurements even when the overall encoder size is reduced.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the rotor track have different radii (first and second radii), creating local quality variations in the flux coupling windings. This local differentiation optimizes signal generation at each position, maintaining measurement accuracy despite downsizing the overall encoder structure.

Inventive Principle:
Principle #3Local quality

2Volume of moving object

If the transmitting winding group is positioned outward of the innermost receiving winding, then the encoder can be downsized, but the structural complexity increases

Engineering Contradiction:
Improveencoder sizeVSAvoidwinding arrangement complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The transmitting winding group is positioned in a different radial dimension (outward of the innermost receiving winding) rather than following the conventional inward arrangement. This dimensional repositioning enables compact encoder design while managing structural complexity through optimized spatial arrangement of the windings.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 maintains signal intensity and reduces measurement errors, achieving improved accuracy and compactness of the absolute rotary encoder, even when downsized, as demonstrated by enhanced signal intensity and reduced displacement errors.

Implementation Method 1

a rotary encoder comprises a stator having transmitting windings and receiving windings arranged thereon, and a rotor having tracks arranged thereon as capable of flux coupling with these windings

Methodology Applied
Scientific EffectFlux coupling: Electromagnetic Induction

Data Source

PatentEP1715298B1Absolute rotary encoder and micrometer
Publication Date: 2017.07.19 MITUTOYO CORP
  • EP1715298B1 patent drawingFigure 1~2
  • EP1715298B1 patent drawingFigure 3~4
  • EP1715298B1 patent drawingFigure 5~6

AI summary

An absolute rotary encoder comprises a rotor having a bore passing through the center thereof to receive a shaft therein and arranged rotatably about the shaft and opposite a stator. Tracks are arranged concentrically on the rotor to form a track group. A transmitting winding group is arranged on the stator as capable of flux coupling with the track group. A receiving winding group is arranged on the stator as capable of flux coupling with the track group. Each track in the track group comprises a flux coupling winding that includes linear arc portions having first and second radii and arranged alternately on the rotor and has the shape of a ring continuous about the shaft. At least two tracks in the track group have the linear arc portions different in number from each other.