Semi-Annular Retaining Ring for Low-Load Turbine Assembly Installation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Internal retaining rings in gas turbine engines face challenges due to high spring-back forces, making installation difficult and causing excessive radial loads that lead to stress concentrations and reduced component lifespan, especially in constrained spaces.

Innovation Solution

A semi-annular internal retaining ring design with radially outward anti-rotation tabs and radially inward protruding tabs with recessed portions, allowing for engagement with anti-rotation features and reduced spring-back forces, facilitating easier installation and axial retention without relying on high stiffness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If internal retaining rings rely on internal spring-back forces to prevent rotation, then rotation prevention is achieved, but installation becomes difficult and excessive radial loads are produced

Engineering Contradiction:

Improverotation preventionVSAvoidinstallation difficulty

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The retaining ring is segmented into a semi-annular body with discrete radially outward protruding anti-rotation tabs at its ends. These tabs can be selectively engaged with anti-rotation features on the outer component, providing rotation prevention without requiring the entire ring to generate high spring-back forces. This segmentation allows the majority of the ring body to be more flexible and easier to install while specific tabs handle the anti-rotation function.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The anti-rotation tabs are designed with specific local properties - they protrude radially outward and can be engaged with corresponding features on the outer component. This local anti-rotation capability is concentrated at the tabs rather than requiring the entire ring to be stiff, allowing the rest of the ring to maintain flexibility for easier installation and reduced radial loads.

Inventive Principle:

Principle #3Local quality

2Reliability

If internal retaining rings rely on internal spring-back forces to prevent rotation, then rotation prevention is achieved, but excessive radial loads are produced causing stress concentrations

Engineering Contradiction:

Improverotation preventionVSAvoidstress concentrations

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

By segmenting the anti-rotation function into discrete tabs rather than requiring uniform spring-back forces around the entire ring, the localized stress concentrations are reduced. The tabs can be strategically positioned to engage with anti-rotation features, distributing the rotational constraint forces more evenly and reducing peak stress concentrations on the retained component.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The anti-rotation tabs provide localized rotation prevention at specific engagement points rather than requiring continuous high spring-back forces around the entire ring circumference. This localized approach reduces the overall radial loads and corresponding stress concentrations on the retained component while still effectively preventing rotation.

Inventive Principle:

Principle #3Local quality

3Reliability

If internal retaining rings are installed between two components with limited spacing, then axial retention is achieved, but installation space is constrained

Engineering Contradiction:

Improveaxial retentionVSAvoidinstallation space

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The semi-annular body of the retaining ring is designed to be flexible and deformable, allowing it to be compressed radially inward for installation in tight spaces between components. The ring can be temporarily deformed to a smaller diameter, passed through the limited spacing between components, and then springs back to its original shape to provide axial retention. This flexibility enables installation in constrained spaces without compromising the axial retention function.

Inventive Principle:

Principle #30Flexible shells and thin films

Data Source

PatentUS11560807B2Internal retaining ring for a rotating assembly in a gas turbine engine

Publication Date: 2023.01.24 PRATT & WHITNEY CANADA CORP

AI summary

An internal retaining ring for placement in a bore of an outer component of a rotating assembly comprises a semi-annular body having an outer circumferential surface with a curvature defined about a first center of curvature and radially outward protruding anti-rotation tabs operable for engagement with a corresponding anti-rotation feature of the outer component. An inner circumferential surface of the semi-annular body has radially inward protruding tabs circumferentially spaced apart around the inner circumferential surface. The radially inward protruding tabs have radially inner surfaces concentric with the outer circumferential surface, and recessed portions between the radially inward protruding tabs and having curvatures defined about a second center of curvature, the second center of curvature different from the first center of curvature.