Turbine Case Retaining Ring Keying for Radial Retention

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Solution Overview

Problem

In gas turbine engines, retaining rings often lack radial retention when no adjacent static structure is available, leading to unwanted movement during engine operation, which can cause wear and stress.

Innovation Solution

A key system comprising a key washer, fastener, and nut is installed on the retaining ring, allowing it to be aligned with a case slot, thereby restricting circumferential and radial motion through engagement with the slot and support tabs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a retaining ring is installed without adjacent static structure, then installation flexibility is improved, but radial retention and stability deteriorate

Engineering Contradiction:

Improveinstallation flexibilityVSAvoidradial retention

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces a key system comprising a key washer, fastener, and nut as intermediary components between the retaining ring and the turbine case. The key washer engages with a case slot to provide radial retention, while the fastener and nut secure the key washer to the retaining ring, thereby enabling reliable installation without adjacent static structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a key system is added to the retaining ring, then radial retention and stability are improved, but device complexity increases

Engineering Contradiction:

Improveradial retentionVSAvoidassembly complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The retaining ring assembly is segmented into distinct functional components: the retaining ring itself, the key washer for radial retention, and the fastener-nut assembly for securing. This segmentation allows each component to perform its specific function efficiently while enabling modular installation and maintenance.

Inventive Principle:

Principle #1Segmentation

3Ease of operation

If the retaining ring is allowed to move freely, then ease of installation is improved, but wear and stress increase

Engineering Contradiction:

Improveease of installationVSAvoidwear and stress

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The key system is pre-assembled with the retaining ring before installation into the turbine case. The key washer is positioned to engage the case slot, and the fastener-nut assembly is prepared to secure the key washer, ensuring that radial retention is established before the retaining ring is subjected to operational loads, thereby preventing excessive wear and stress.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS10975773B2System and method for limiting movement of a retaining ring

Publication Date: 2021.04.13 RTX CORP

AI summary

A method of installing a retaining ring assembly in a turbine case is provided. The method may include installing a blade outer air seal into a case before installation of a retaining ring assembly. The method may further include installing a key system on a retaining ring to create the retaining ring assembly. The method may also include installing the retaining ring assembly in a case. The method may further include rotating the retaining ring assembly in the case until key system is aligned with a case slot. The method may also include tightening the key system to the retaining ring and cause key system to engage the case slot.