Resilient Balancing Weight Clip for Gas Turbine Rotor

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Solution Overview

Problem

In gas turbine engines, existing methods for balancing rotors using additional securing devices increase complexity and weight, and do not effectively address the fatigue issues of higher temperature, yet brittle, materials used in turbine disc assemblies.

Innovation Solution

A rotor assembly design featuring a disc with a flange having recesses and a balancing weight clip with elastically deformable flange engaging portions that securely attach to the flange without additional fastening means, ensuring balance and stability while minimizing weight and complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional securing devices such as rivets are used to attach balancing weights to the rotor, then the balancing weight is securely attached, but the total weight of the assembly increases and the complexity of the assembly increases

Engineering Contradiction:

Improvesecure attachment of balancing weightVSAvoidtotal weight of rotor assembly

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The securing function is merged into the balancing weight clip itself through the resilient flange engaging portions that directly engage with the flange grooves. This eliminates the need for separate rivets or fasteners, thereby securing the balancing weight without adding extra components that would increase total assembly weight.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The resilient flange engaging portions automatically secure the balancing weight to the rotor flange through elastic deformation and engagement with the grooves. The clip serves its own securing function without requiring external fastening devices, thus avoiding additional weight while maintaining reliable attachment.

Inventive Principle:

Principle #25Self-service

2Reliability

If additional securing devices such as rivets are used to attach balancing weights to the rotor, then the balancing weight is securely attached, but the complexity of the assembly increases

Engineering Contradiction:

Improvesecure attachment of balancing weightVSAvoidcomplexity of rotor assembly

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The resilient flange engaging portions automatically secure the balancing weight to the rotor flange through elastic deformation and engagement with the grooves. The clip serves its own securing function without requiring external fastening devices, thus simplifying the overall assembly by reducing the number of different component types.

Inventive Principle:

Principle #25Self-service

3Temperature

If higher temperature materials are used for turbine disc assemblies, then the temperature resistance is improved, but the materials become more brittle and fatigue life decreases

Engineering Contradiction:

Improvetemperature resistance of turbine discVSAvoidfatigue life of turbine disc

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The design changes the mechanical parameter of stress distribution by using a resilient balancing weight clip that distributes loads more evenly across the flange interface. This reduces stress concentration points that would be particularly detrimental to brittle, high-temperature materials, thereby improving fatigue life while maintaining temperature resistance.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The resilient flange engaging portions act as a cushioning element that absorbs and distributes mechanical stresses before they can concentrate on the brittle turbine disc material. This pre-cushioning effect protects the high-temperature materials from stress-induced fatigue failures.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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 provides a lightweight, low-complexity method for balancing gas turbine rotor assemblies, enhancing fatigue life by eliminating the need for additional securing devices and ensuring secure attachment of balancing weights without compromising axial, circumferential, or radial stability.

Implementation Method 1

at least one of the first and second flange engaging portions being resiliently biased so that the first and second flange engaging portions are elastically moveable away from one another

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS8631578B2Radial balancing clip weight for rotor assembly

Publication Date: 2014.01.21 PRATT & WHITNEY CANADA CORP

AI summary

A balancing weight clip with a mass adapted to balance a rotor assembly of a gas turbine engine, includes a weight portion, a first flange engaging portion and a second flange engaging portion extending from the weight portion, each being engageable with a sidewall of at least one recess located on an edge of a flange of a disc of the rotor assembly. Each flange engaging portion is provided with a hook engageable with a mating groove provided on a face of the flange. At least one of the first and second flange engaging portions is resiliently biased so that the first and second flange engaging portions are elastically moveable away from one another to removably secure the balancing weight clip to the flange and engage each hook with the mating groove.