Rotation Angle Sensor Miniaturization via Segmented Coil Spacing

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Solution Overview

Problem

Existing rotation angle detecting sensors face accuracy degradation due to increased density of connections between adjacent coils when trying to miniaturize the sensor or increase the cycle number, leading to errors in detection results.

Innovation Solution

A rotation angle detecting sensor with an encoder structure having n cycles of phases and inductance elements spaced 90 degrees apart, ensuring a distance of at least half a phase between adjacent elements, reducing interaction and enhancing accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the diameter of the sensor is reduced or the cycle number of the conductor pattern is increased, then the resolution and precision of angle detection are improved, but the connection between adjacent coils becomes dense causing magnetic field changes and detection errors

Engineering Contradiction:
Improveangle detection precisionVSAvoiddetection accuracy
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The sensor is divided into multiple independent coil units (first coil unit, second coil unit, third coil unit, fourth coil unit) arranged at different angular positions. Each coil unit independently detects magnetic field information, and the results are synthesized to achieve high-precision angle detection while avoiding interference from adjacent coils through proper spatial distribution.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a one-dimensional linear arrangement of coils to a two-dimensional circular arrangement around the rotor. By distributing coils in the angular dimension (0°, 90°, 180°, 270° positions), the system achieves better spatial separation and reduces magnetic field interference while maintaining high detection precision.

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

2Volume of moving object

If the distance between adjacent coils is reduced to miniaturize the sensor, then the sensor size is reduced, but the interaction between adjacent coils increases causing detection errors

Engineering Contradiction:
Improvesensor sizeVSAvoiddetection accuracy
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

The sensor is divided into multiple independent coil units (first coil unit, second coil unit, third coil unit, fourth coil unit) arranged at different angular positions. Each coil unit independently detects magnetic field information, and the results are synthesized to achieve high-precision angle detection while avoiding interference from adjacent coils through proper spatial distribution.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different coil units are positioned at specific angular locations (0°, 90°, 180°, 270°) around the rotor, creating localized detection zones. This spatial distribution ensures that each coil operates in a relatively isolated magnetic field environment, reducing mutual interference while maintaining compact overall sensor dimensions.

Inventive Principle:
Principle #3Local quality

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 improves sensor accuracy by maintaining sufficient distance between inductance elements, allowing for miniaturization and increased cycle numbers without degrading detection precision.

Implementation Method 1

an angle sensor for detecting the angle of the rotor is provided... based on a method for detecting the magnetic field of a permanent magnet of the rotor

Methodology Applied
Scientific EffectMagnetic field detection: Magnetic Field

Implementation Method 2

a rotation angle detecting sensor based on eddy current loss principle... the loss caused in the inductance is intentionally changed due to the eddy current generated in the encoder structure

Methodology Applied
Scientific EffectEddy current loss: Eddy Currents

Data Source

PatentEP2221588B1Rotation angle detecting sensor
Publication Date: 2015.01.14 SUMIDA CORP
  • EP2221588B1 patent drawingFigure 1A~1B
  • EP2221588B1 patent drawingFigure 2~3
  • EP2221588B1 patent drawingFigure 4A~4B

AI summary

The present invention is made to provide a rotation angle detecting sensor capable of being miniaturized. The rotation angle detecting sensor includes a rotating body; an encoder structure 3 having n (n represents a positive integer) cycles of phases each ranging from phase 0° to phase 360°, each phase being formed by periodically changing the width of the conductor pattern; and a sensor body having a plurality of inductance elements C1, C2, C3, C4 and disposed opposing the encoder structure 3 with a space. The cycle number n of the phase of the encoder structure 3 is a positive integer equal to or greater than three, the plurality of inductance elements C1, C2, C3, C4 have a phase difference of 90 degrees therebetween, and the two adjacent inductance elements are disposed apart from each other by a space of at least half a phase of the encoder structure 3.