Accessory Gearbox Casing Central Support Design

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Solution Overview

Problem

The existing housing designs for gas turbine accessory relay boxes are complex, costly, and time-consuming to manufacture due to their multi-functional nature, which complicates assembly and requires unnecessary material usage.

Innovation Solution

A housing design where each shaft is guided by one or more bearings carried by a single support inserted between the front and rear faces, allowing for a cantilever arrangement of toothed wheels and simplifying assembly and machining by dissociating support functions from other functions, with a central support taking up meshing and structural forces, and optionally featuring a perforated lattice structure for reduced mass.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If bearings are supported by separate brackets at each end of shafts, then shaft guidance is achieved, but device complexity and assembly difficulty increase

Engineering Contradiction:
Improveshaft guidanceVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Multiple bearing supports that were previously distributed as separate brackets at each end of shafts are merged into a single central support structure. This consolidation reduces the number of parts and simplifies assembly operations while maintaining the shaft guidance function.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single central support structure serves multiple functions: it supports all bearing housings, provides a centralized lubrication system, and acts as a structural element for the entire gearbox assembly. This multi-functionality reduces the need for separate components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If multiple bearing housings are distributed on both sides of gears, then shaft support is provided, but manufacturing and machining complexity increase

Engineering Contradiction:
Improveshaft supportVSAvoidmachining complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Multiple bearing housings are consolidated into a single integrated support structure rather than being distributed as separate components. This merging simplifies machining operations by reducing the number of separate parts that need to be manufactured and assembled.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The support structure is designed with modular bearing housings that can be independently manufactured and then assembled into the central support, allowing for simplified machining of each segment while maintaining overall structural integrity.

Inventive Principle:
Principle #1Segmentation

3Strength

If front and rear faces perform multiple functions including bearing support, then structural integrity is maintained, but manufacturing time and cost increase

Engineering Contradiction:
Improvestructural integrityVSAvoidmanufacturing efficiency
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The gearbox is divided into functional modules: the central support handles bearing support functions, while the front and rear faces are dedicated to sealing and structural functions. This segmentation allows each component to be optimized and manufactured independently, reducing overall manufacturing time.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bearing support function is extracted from the front and rear faces and consolidated into a dedicated central support structure. This extraction allows the front and rear faces to be simplified for manufacturing while the central support is专门 designed for bearing accommodation.

Inventive Principle:
Principle #2Taking out (Extraction)

4Ease of operation

If a single central support is used for all bearing housings, then assembly is simplified, but support for multiple shafts must be achieved from one location

Engineering Contradiction:
Improveassembly simplicityVSAvoidsupport structure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The single central support structure extends in multiple spatial dimensions to accommodate bearing housings for multiple shafts. By utilizing three-dimensional space efficiently, one support structure can provide guidance for multiple shafts without requiring multiple separate supports.

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

Solution Approach 2:

Multiple bearing housings are nested within or attached to the central support structure in a hierarchical arrangement, allowing all bearings to be supported from a single location while maintaining easy access for assembly and maintenance.

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP3679233B1Accessory gearbox for turbomachine
Publication Date: 2024.10.30 SAFRAN TRANSMISSION SYST
  • EP3679233B1 patent drawingFigure 1A~1C
  • EP3679233B1 patent drawingFigure 2~3

AI summary

The invention relates to an accessory gearbox casing (10, 110, 210) for a turbomachine with a lateral front face (16, 116, 216) and a lateral rear face (18, 118, 218) opposite the front face, laterally defining the accessory gearbox in which at least one gear train made of several toothed wheels (14) that engage with one another is mounted, each toothed wheel (14) being supported by a central shaft (28), characterized in that the shafts (28) are guided in rotation by bearings (30) with roller bearings all supported by a same support (12, 112, 212) inserted laterally between the front face (16, 116, 216) and the rear face (18, 118, 218).