Integrated Eddy Current Sensing for Rotary Shaft Position and Speed

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Solution Overview

Problem

Current eddy current sensors cannot accurately detect the rotating speed of maglev rotary shafts, limiting comprehensive monitoring and real-time control of maglev motor performance.

Innovation Solution

An eddy current sensor integrating position detecting probes and rotating speed detecting probes, allowing simultaneous detection of position displacement and rotating speed, with corresponding data analysis for intensive monitoring of the rotary shaft's working state.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a contact type detecting device is used to detect the rotary shaft, then the detection accuracy is improved, but the device cannot be applied to high-speed maglev rotary shafts due to contact limitations

Engineering Contradiction:
Improvedetection accuracyVSAvoidapplicability to high-speed maglev rotary shafts
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent replaces the mechanical contact type detecting device with a non-contact eddy current sensor. The eddy current sensor uses electromagnetic induction to detect the position and speed of the maglev rotary shaft without physical contact, thereby maintaining high detection accuracy while being suitable for high-speed applications where contact devices would fail.

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

Solution Approach 2:

The patent introduces an intermediary target structure with conductive material on the maglev rotary shaft that interacts with the eddy current sensor. This target structure serves as a mediator that enables the non-contact sensor to detect position and speed information through eddy current effects, bridging the gap between the sensor and the rotating shaft.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If an eddy current sensor is used to detect position displacement of the maglev rotary shaft, then the non-contact detection capability is achieved, but the rotating speed detection function is lost

Engineering Contradiction:
Improvenon-contact detection capabilityVSAvoidrotating speed detection accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent designs the eddy current sensor to perform multiple functions simultaneously. By using a single eddy current sensor to detect both the position displacement and the rotating speed of the maglev rotary shaft, the system achieves multi-functionality without requiring separate sensors, thereby maintaining non-contact capability while enabling speed detection.

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

Solution Approach 2:

The patent segments the detection functions into different detection modes within the same sensor system. The eddy current sensor processes different signal characteristics from the target structure to separately obtain position information and speed information, allowing both functions to be achieved through signal analysis of the same non-contact detection process.

Inventive Principle:
Principle #1Segmentation

3Measurement precision

If separate sensors are used for position detection and speed detection, then the detection functions are specialized, but the device complexity increases

Engineering Contradiction:
Improvedetection function specializationVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the position detection and speed detection functions into a single eddy current sensor system. The sensor uses the same non-contact detection mechanism to obtain both types of information by analyzing different aspects of the eddy current signals, thereby reducing device complexity while maintaining specialized detection capabilities for both position and speed.

Inventive Principle:
Principle #5Merging (Combining)

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

Enables comprehensive and precise monitoring of the rotary shaft's position and speed, facilitating improved analysis and control of the maglev motor's working state.

Implementation Method 1

an eddy current sensor is employed to perform position detection of the maglev rotary shaft

Methodology Applied
Scientific EffectEddy current: Eddy Currents

Data Source

PatentEP3964788B1Eddy current sensor for rotary shaft, and rotary shaft apparatus
Publication Date: 2023.10.04 ZHUHAI GREE REFRIGERATION TECH CENT OF ENERGY SAVING & ENVIRONMENTAL PROTECTION
  • EP3964788B1 patent drawingFigure 1~2
  • EP3964788B1 patent drawingFigure 3~4

AI summary

The present application provides an eddy current sensor for a rotary shaft and a rotary shaft apparatus. The eddy current sensor comprises: a housing; one or more eddy current type probes provided on the housing, arranged to detect the shaft position by measuring the distance between the probe and the shaft; and a rotating speed detecting probe provided on the housing. By applying the technical solution of the present application, the eddy current sensor integrates the distance detecting probe and the rotary speed detecting probe, such that while the eddy current sensor is detecting a positional displacement of the rotary shaft, it may also simultaneously detect the rotating speed of the rotary shaft, which facilitates detecting and monitoring the rotary shaft more comprehensively; besides, the detected position data and rotating speed data of the rotary shaft are corresponding to each other at any time, such that the working state of the rotary shaft may be analyzed more intensively. The housing is filled with a potting material, so that interstices within the housing are filled and the probes are plastically sealed.