Gearbox Mount Bracket Load Distribution via Rail-Slot Segmentation

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Solution Overview

Problem

Existing gearbox mounting arrangements for gas turbine engines do not effectively distribute tangential and axial loads, potentially leading to risk of breakage and increased stress on bolts due to inadequate load distribution.

Innovation Solution

A bracket system with upper and lower mounts and flanges that conform to the engine casing, featuring arcuate shapes and rail-slot configurations to minimize load transmission to bolts, along with lobes and attachment plates for secure attachment of the gearbox, thereby distributing loads and reducing the risk of breakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional band mounting arrangement is used to attach the gearbox to the engine casing, then the gearbox can be mounted to the engine, but the bolts experience increased stress and there is a risk of breakage due to inadequate load distribution

Engineering Contradiction:
Improvemounting reliabilityVSAvoidbolt strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The mounting arrangement is divided into multiple discrete brackets (upper and lower) that are distributed around the engine casing. Each bracket independently handles portion of the load, segmenting the stress distribution across multiple attachment points rather than concentrating it in a single band structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mounting system transitions from a two-dimensional band encircling the engine to a three-dimensional distributed bracket system with upper and lower mounts positioned at different heights and angles. This spatial distribution across multiple dimensions allows for more effective load path management and stress dispersion.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Stability of the object's composition

If a rigid mounting structure is used to securely attach the gearbox, then the gearbox is firmly mounted, but the structure transmits more loads and increases the risk of breakage

Engineering Contradiction:
Improvemounting stabilityVSAvoidload transmission
Core Design Contradiction:
Stability of the object's compositionVSForce

Solution Approach 1:

The bracket design incorporates localized structural features including arcuate shapes that conform to the engine casing curvature, flanges for load distribution, and rail-slot configurations at specific locations. Each local feature is optimized to handle specific stress patterns, with the arcuate portions managing tangential loads and the flanges managing axial loads.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The bracket structure acts as an intermediary element between the engine casing and the gearbox, featuring upper and lower mounts with flanges that create intermediate load transfer paths. The rail-slot configurations serve as mechanical intermediaries that allow controlled movement while maintaining stable connection, reducing direct load transmission.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If larger bolts are used to prevent breakage, then the mounting becomes more reliable, but the device complexity and weight increase

Engineering Contradiction:
Improvemounting reliabilityVSAvoidmounting complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The mounting system uses multiple smaller brackets distributed around the engine rather than a few large heavy bolts. This segmentation allows the use of smaller, simpler fasteners at each location while achieving overall system reliability through the collective strength of multiple attachment points.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The design distributes mounting points across three-dimensional space with upper and lower brackets at different positions, eliminating the need for oversized bolts by utilizing spatial distribution. This multi-dimensional arrangement reduces the mechanical complexity associated with large fastener designs.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP2530281B1Gearbox mount bracket
Publication Date: 2017.11.15 UNITED TECH CORP
  • EP2530281B1 patent drawingFigure 1
  • EP2530281B1 patent drawingFigure 1A
  • EP2530281B1 patent drawingFigure 2

AI summary

A bracket (30) for attaching a gearbox to an engine casing (15) has a first portion (105) having a first array (110) of openings for receiving attachments (133) therethrough, the first portion (105) having, on a backside thereof, a rail (70) for engaging a slot (65) in the engine casing (15), and a second portion (115) having a second array (120) of openings for receiving attachments therethrough. A hookup (135) for attaching to the gearbox attaches to and in between the first portion (105) and the second portion (115) for diminishing effects of radial rotation between the casing (15) and the gearbox.