Balancing Annular Parts Using Sensor-Based Unbalance Compensation

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Solution Overview

Problem

Aeronautical bearing cages require precise balancing to minimize vibrations, but existing centering tools are expensive and prone to deforming parts, with limited adaptability and high tolerance errors.

Innovation Solution

A method for balancing annular parts using a rotating balancing plate with sensors and a feeler to measure apparent unbalance and contour, calculating real unbalance by subtracting positioning unbalance from apparent unbalance, and using lightweight plastic clamping means to avoid deformation and additional unbalance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If expensive precision centering tools are used to support the bearing cage on the balancing plate, then centering error is reduced below 5 μm, but device cost increases significantly and the tools are specific to a given centering diameter

Engineering Contradiction:
Improvecentering errorVSAvoiddevice cost
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces expensive mechanical centering tools with a measurement-based approach. A sensor measures the actual position of the bearing cage relative to the balancing plate, and a computing device calculates the true unbalance by compensating for positioning errors through mathematical computation, eliminating the need for costly mechanical centering equipment

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

Solution Approach 2:

The patent introduces a sensor as an intermediary element between the bearing cage and the balancing plate. The sensor measures the relative position without requiring precise mechanical contact or specialized centering tools, enabling accurate measurement through intermediate detection rather than direct mechanical precision

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If traditional centering tools are used to support the bearing cage, then centering is achieved, but the tools tend to deform parts and are limited to specific centering diameters

Engineering Contradiction:
Improvecentering capabilityVSAvoidadaptability to different diameters
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent replaces mechanical centering tools that physically contact and potentially deform the bearing cage with a non-contact or minimal-contact sensor-based measurement system. The sensor detects position information without requiring forceful mechanical engagement, eliminating deformation risks

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

Solution Approach 2:

The patent changes the approach from fixed mechanical centering for specific diameters to a flexible measurement system that can accommodate different diameters. The sensor and computing device calculate positioning errors and true unbalance for any diameter through parameter measurement and computation rather than mechanical constraint

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If bearing cages are precisely balanced with tight tolerance less than 15 μm, then vibration is minimized for high-speed rotation, but the measurement process becomes highly sensitive to positioning errors

Engineering Contradiction:
Improveunbalance toleranceVSAvoidmeasurement sensitivity to positioning error
Core Design Contradiction:
Manufacturing precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent introduces a sensor as an intermediary measurement device that detects the actual positioning of the bearing cage relative to the balancing plate. This intermediary measurement enables the system to identify and compensate for positioning errors through computational correction

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements a feedback mechanism where the sensor measures positioning errors and the computing device calculates the true unbalance by compensating for these errors. The measured positioning information feeds back into the calculation process to correct the unbalance measurement, ensuring accuracy even with positioning variations

Inventive Principle:
Principle #23Feedback

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 method achieves precise balancing with reduced centering errors and cost-effective, adaptable solutions for aeronautical bearing cages, ensuring low eccentricity and accurate unbalance measurement.

Implementation Method 1

A method for balancing an annular part comprises the following steps: placing the annular part on a balancing plate of a balancing bench, the balancing plate being capable of rotating around a reference axis of the balancing bench; measurement, by the balancing bench and by rotating the balancing plate, of an apparent unbalance of the annular part placed on the balancing plate

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3312581B1Method and bench for balancing an annular part
Publication Date: 2020.08.05 NTN SNR ROULEMENTS
  • EP3312581B1 patent drawingFigure 1~2
  • EP3312581B1 patent drawingFigure 3~4
  • EP3312581B1 patent drawingFigure 5

AI summary

To balance an annular part (16) the following steps are taken: the annular part (16) is placed on a balancing plate (12) of a balancing bench, the balancing plate (12) being able to rotate around a reference axis (100) of the balancing bench (10); an apparent imbalance of the annular part (16) is measured by the balancing bench; a dimensional measurement of a contour of a reference annular surface of the annular part (16); and a calculation of an actual imbalance of the annular part (16) as a function of the mass of the annular part (16), the measured contour and the apparent imbalance.