Shaft Rotational Angle Detection Using Single Sensor Signal Processing

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Solution Overview

Problem

Existing systems require multiple sensors to detect changes in the rotational angle of a rotating member, which increases complexity and reduces efficiency.

Innovation Solution

A drive system utilizing a single rotational angle detector with a support unit that supports the shaft in a non-contact manner using electromagnetic force, a drive unit to rotate the shaft, and a signal processing unit to generate a second signal by reducing specific frequency components, allowing accurate detection of the shaft's rotational angle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If two sensors (rotation detector and shaft runout detector) are used to detect rotational angle changes, then detection accuracy is improved, but the number of sensors increases and system complexity worsens

Engineering Contradiction:
Improverotational angle detection accuracyVSAvoidnumber of sensors
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the functions of rotation detection and shaft runout detection into a single rotational angle detector. The detector simultaneously captures both the rotational angle information and the shaft runout information, eliminating the need for separate sensors while maintaining detection accuracy through signal processing that separates these two components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single rotational angle detector is designed to perform multiple functions: detecting both the rotational angle of the shaft and the shaft runout. This multi-functional detector replaces what would traditionally require two separate sensors, reducing system complexity while preserving measurement capabilities.

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

2Reliability

If two sensors are used for detection, then comprehensive rotational information is obtained, but installation complexity and maintenance difficulty increase

Engineering Contradiction:
Improvedetection completenessVSAvoidsensor maintenance
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

By merging the detection functions into a single sensor, the patent reduces the number of components that require installation and maintenance. The single rotational angle detector captures all necessary rotational information, simplifying both installation procedures and maintenance operations compared to managing two separate sensors.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If multiple sensors are deployed, then detection coverage is improved, but system cost and complexity increase

Engineering Contradiction:
Improverotational angle detectionVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges multiple detection functions into a single sensor system, reducing the total number of sensors required. This approach maintains comprehensive rotational angle detection capability while significantly reducing system complexity, installation requirements, and associated costs.

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

The system reduces the number of sensors needed for rotational angle detection, enabling accurate and efficient detection of the shaft's rotational angle and runout components using a single detector.

Implementation Method 1

a support unit (11) configured to support the shaft (20) in a non-contact manner using an electromagnetic force

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

a drive unit (12) configured to rotationally drive the shaft (20) using an electromagnetic force

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentEP4672591A1Drive system, turbo compressor, and refrigeration device
Publication Date: 2025.12.31 DAIKIN INDUSTRIES LTD
  • EP4672591A1 patent drawingFigure 1
  • EP4672591A1 patent drawingFigure 2
  • EP4672591A1 patent drawingFigure 3~4

AI summary

A rotational angle detector (60) outputs a first signal (S1) on which a specific frequency component is superimposable. The first signal (S1) has an amplitude that changes in accordance with a change in a rotational angle of a shaft (20). A signal processing unit (80) generates, based on the first signal (S1), a second signal (S2) by performing a reduction process for reducing the specific frequency component included in the first signal (S1). A control unit (90) detects the rotational angle of the shaft (20) based on the second signal (S2). A frequency of the specific frequency component is lower than a frequency of a first frequency component (C1) included in the first signal (S1), the first frequency component (C1) being an alternating-current frequency component other than a direct-current component and corresponding to the change in the rotational angle of the shaft (20).