Gas Turbine Linkage Assembly With Spring Anti-Rotation Bias

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Solution Overview

Problem

In gas turbine engines, linkage assemblies with radial spherical plain bearing links allow for three rotational degrees of freedom, resulting in an unconstrained rotational degree of freedom about the longitudinal axis, which needs to be addressed without replacing existing hardware.

Innovation Solution

A linkage assembly is designed with a biasing member, including an elastic biasing member such as a flat U-shaped spring, secured between the flange and the sliding bearing housing, which contacts the sliding bearing housing to bias the link against rotation about its center axis, eliminating the unwanted rotational freedom.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If radial spherical plain bearing links are used to allow three rotational degrees of freedom, then the linkage assembly achieves greater mobility and flexibility, but an unwanted unconstrained rotational degree of freedom about the longitudinal axis is introduced

Engineering Contradiction:
Improverotational degrees of freedomVSAvoidrotational constraint
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

A biasing member (spring) is introduced as an intermediary element between the link and the bearing housing. This spring applies a continuous biasing force that constrains the link's longitudinal axis, eliminating the unwanted rotational degree of freedom while preserving the other three rotational degrees of freedom provided by the spherical plain bearing.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If existing hardware is retained without replacement, then cost and complexity are reduced, but the unwanted rotational degree of freedom cannot be eliminated

Engineering Contradiction:
Improvehardware configurationVSAvoidrotational constraint
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The solution segments the constraint function from the existing bearing hardware. Instead of replacing the entire bearing assembly, only a simple biasing member (spring) is added as a separate component. This segmented approach maintains compatibility with existing hardware while adding the necessary rotational constraint function.

Inventive Principle:
Principle #1Segmentation

3Stability of the object's composition

If a biasing member is added to constrain rotation about the longitudinal axis, then rotational stability is improved, but device complexity increases

Engineering Contradiction:
Improverotational constraintVSAvoidlinkage assembly structure
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The biasing member changes the mechanical parameter of the system by introducing a continuous biasing force that limits rotational motion. This parameter change (adding elastic force) achieves rotational constraint with a simple component that does not significantly complicate the overall linkage assembly structure.

Inventive Principle:
Principle #35Parameter changes

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 configuration effectively restricts rotational motion about the longitudinal axis, enhancing the stability and functionality of the linkage assemblies in gas turbine engines without requiring hardware replacement.

Implementation Method 1

the biasing member is an elastic biasing member that includes a first annular spacer having a first opening through which the pin extends

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3657034B1Linkage assembly
Publication Date: 2021.08.25 RTX CORP
  • EP3657034B1 patent drawingFigure 1
  • EP3657034B1 patent drawingFigure 2A
  • EP3657034B1 patent drawingFigure 2B

AI summary

Disclosed is a linkage assembly for a gas turbine engine (20) having a link (102a-102d) having a first end (104a), a second end (104b), and a rod (106) extending therebetween, the first end having a first sliding bearing (108) disposed within a first sliding bearing housing (107), a fastener (118) comprising a first flange (126a) and a second flange (126b), a pin (120) extending between the first flange and the second flange, wherein the first sliding bearing is pivotally connected to the pin; and a biasing member (136a, 136b) secured between the first flange and the sliding bearing housing, the biasing member contacting the sliding bearing housing and biasing the link against rotation about a center axis for the rod of the link.