Turbomachine Rotor Balancing Ring Design

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Solution Overview

Problem

Rotors for turbomachines face challenges in balancing, space optimization, weight reduction, and preventing oil accumulation, which affects performance and maintenance, particularly in high-speed applications like aircraft engines.

Innovation Solution

A rotor design featuring a balancing ring integrally connected to the rotor arm via a press fit, positioned on the radially outer side to facilitate form-fitting flanging of basic rotor bodies, allowing for efficient balancing and oil drainage without internal cavities, thereby reducing weight and installation space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If a balancing ring is connected to the rotor arm by means of a screw connection or form-fitting connection without press fit, then the balancing ring can be easily released for maintenance, but the connection strength and reliability are reduced

Engineering Contradiction:
Improveease of releasing balancing ringVSAvoidconnection strength
Core Design Contradiction:
Ease of repairVSStrength

Solution Approach 1:

The patent changes the connection parameter from a mechanical connection (screw or form-fitting) to a press-fit connection, which provides both strong connection and ease of release through controlled interference fit. The press-fit connection allows the balancing ring to be securely attached during operation but easily removed when needed, resolving the contradiction between connection strength and ease of repair.

Inventive Principle:
Principle #35Parameter changes

2Volume of moving object

If the balancing ring is arranged in the interior of the rotor, then the space utilization is improved, but oil accumulations can form in cavities causing contamination risks

Engineering Contradiction:
Improvespace utilizationVSAvoidoil accumulation and contamination
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the balancing ring from the rotor interior and positions it on the radially outer side of the rotor. This extraction eliminates the cavity where oil could accumulate, thereby removing the source of contamination while still providing the necessary balancing function. The balancing ring is now positioned where it cannot trap oil, resolving the contradiction between space utilization and preventing harmful oil accumulations.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of manufacture

If the rotor design includes internal cavities for structural purposes, then the manufacturing flexibility is improved, but oil accumulations in these cavities cannot be prevented

Engineering Contradiction:
Improvemanufacturing flexibilityVSAvoidoil accumulation
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent converts the potential harm of internal cavities by repositioning the balancing ring to the radially outer side, where it serves as a barrier that prevents oil from entering and accumulating in internal cavities. The balancing ring structure, which could potentially create dead zones, is instead positioned to actively prevent oil migration into cavities, transforming the design into a solution that maintains manufacturing flexibility while preventing oil accumulation.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

4Ease of operation

If the balancing ring is made as a separate component for assembly, then the ease of assembly is improved, but the integral connection and structural integrity are reduced

Engineering Contradiction:
Improveease of assemblyVSAvoidintegral connection
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent merges the balancing ring with the rotor arm through a press-fit connection, creating an integrated assembly that maintains structural integrity while still allowing for separate manufacturing and assembly. The press-fit connection provides a unified, stable structure that behaves as a single component during operation, resolving the contradiction between ease of assembly and integral connection by combining the benefits of both separate assembly and unified structure.

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 design enhances rotor balance, reduces oil contamination risks, optimizes space and weight, leading to improved performance and economic benefits through reduced kerosene consumption and compactness.

Implementation Method 1

The balancing ring can be referred to as a balancing collar. The balancing ring of the rotor according to the invention is integrally connected to the rotor arm for form-fitting flanging of the second basic rotor body to the first basic rotor body. The balancing ring which is integrally connected to the rotor arm can be a balancing ring which is connected to the rotor arm by means of a force-fit press fit.

Methodology Applied
Scientific EffectPress fit: Mechanical Force

Implementation Method 2

accumulations of oil in cavities in the interior of the rotor, for example accumulations of bearing oil, should be able to flow out of the interior of the rotor

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3091177B1Rotor for a flow engine and compressor
Publication Date: 2017.12.20 MTU AERO ENGINES GMBH
  • EP3091177B1 patent drawingFigure 1
  • EP3091177B1 patent drawingFigure 2~4
  • EP3091177B1 patent drawingFigure 5

AI summary

The present invention relates to a rotor (100) for a turbomachine, comprising at least a first (111) and a second (121) rotor body, wherein the second rotor body (121) has a rotor arm (123) with an arrangement (1) for positively flanged connection of the first (111) to the second (121) rotor body, and wherein the arrangement (1) has a balancing ring (124) on the radially outer side (3) of the rotor arm (123). The balancing ring (124) is integrally connected to the rotor arm (123) for positively flanged connection of the second rotor body (121) to the first rotor body (111), wherein the arrangement (1) is located at the upstream and/or downstream end of the rotor arm (123). The present invention further relates to a compressor of a turbomachine with a rotor (100) according to the invention.