Inductive Rotation Sensor with Opposite Winding Coils

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Solution Overview

Problem

Existing inductive rotation angle sensors require complex electronics for evaluating coupling factors, leading to increased complexity and sensitivity to assembly tolerances and interference.

Innovation Solution

A sensor arrangement using a disc-shaped target with flat detection coils having opposite winding directions, generating phase-shifted sinusoidal or linear evaluation signals, which are easily calculated to determine the angle of rotation, reducing sensitivity to assembly tolerances and interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If complex electronics are used for evaluating coupling factors in inductive rotation angle sensors, then measurement capability is achieved, but device complexity increases

Engineering Contradiction:
Improverotation angle detection capabilityVSAvoidelectronics complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex electronic evaluation systems with a mechanically simple coil arrangement. By using two flat detection coils with opposite winding directions arranged at specific angles, the system generates evaluation signals through pure electromagnetic induction without requiring complex electronics. The opposing coil windings naturally produce differential signals that simplify the evaluation process while maintaining accurate rotation angle detection capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical parameters of the coil arrangement - specifically using opposite winding directions and specific angular positions - to transform the coupling factor evaluation into a simpler process. This parameter change allows the system to generate evaluation signals with favorable characteristics directly through the coil geometry, reducing the need for complex electronic processing.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If conventional coil arrangements are used, then inductive coupling is achieved, but sensitivity to assembly tolerances and interference increases

Engineering Contradiction:
Improveinductive coupling stabilityVSAvoidsensitivity to assembly tolerances and interference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent employs asymmetric coil winding directions (opposite polarities) to create a differential measurement system. This asymmetry in winding direction, combined with symmetric angular positioning, produces evaluation signals that are inherently less sensitive to assembly tolerances and electromagnetic interference. The opposing windings create complementary signal patterns that cancel out common-mode disturbances.

Inventive Principle:
Principle #4Asymmetry

3Ease of operation

If simple evaluation methods are used, then ease of calculation is improved, but measurement precision may be compromised

Engineering Contradiction:
Improveevaluation simplicityVSAvoidrotation angle accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent segments the measurement function into two independent flat detection coils with opposite windings. Each coil provides a separate evaluation signal that can be processed through simple calculation rules. This segmentation allows the use of straightforward evaluation methods while maintaining measurement precision, as the differential nature of the segmented coil outputs preserves accurate rotation angle information.

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 allows for simple calculation of the angle of rotation with improved electromagnetic compatibility (EMC) and reduced sensitivity to assembly tolerances, enabling efficient contactless detection of rotational angles.

Implementation Method 1

The at least one metal surface of the rotating target influences the inductance of the at least one flat detection coil as a function of the degree of overlap by eddy current effects

Methodology Applied
Scientific EffectEddy current effects: Eddy Currents

Implementation Method 2

A sensor arrangement for contactless detection of angles of rotation with a coil arrangement (40) which has at least one flat detection coil (42, 44, 46)

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3204727B1Sensor arrangement for contactless measurement of the rotation angle of a rotating part
Publication Date: 2018.09.05 ROBERT BOSCH GMBH
  • EP3204727B1 patent drawingFigure 1
  • EP3204727B1 patent drawingFigure 2
  • EP3204727B1 patent drawingFigure 3

AI summary

The invention relates to a sensor arrangement (1) for the contactless detection of rotational angles on a rotating component, the rotating component being coupled to a disk-shaped target (20) which has at least one metal surface (24) and which, in combination with a coil arrangement (40) which has at least one flat detection coil (42, 44, 46), generates at least one item of information for determining the current rotational angle of the rotating component. According to the invention, the at least one flat detection coil (42, 44, 46) has two coil sections (42.1, 42.2, 44.1, 44.2, 46.1, 46.2) which have opposite winding directions and are arranged opposite each other on the periphery of a circle, the at least one metal surface (24) of the rotating target (20) influencing, by eddy current effects, the inductance of the at least one flat detection coil (42, 44, 46) depending on the degree of overlap.