Multi-Gearbox Accessory Drive Layout for Compact Turbine Engines

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Solution Overview

Problem

Existing accessory gearboxes in gas turbine engines have limitations that hinder efficient power transmission and space optimization within the engine.

Innovation Solution

The proposed assembly for a turbine engine includes an inner tower shaft, a layshaft, an outer tower shaft, an intermediate gear system, an inner gearbox, and an outer gearbox, with bevel gearing connections to efficiently transfer mechanical power and optimize space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single accessory gearbox is used to mechanically couple engine accessories to the turbine engine, then the structure is simpler, but the space requirements increase and power transmission efficiency decreases

Engineering Contradiction:

Improvegearbox structureVSAvoidspace requirements

Core Design Contradiction:

Device complexityVSVolume of moving object

Solution Approach 1:

The accessory gearbox system is divided into multiple separate gearboxes (inner gearbox and outer gearbox) that are distributed around the engine periphery. This segmentation allows each gearbox to be positioned in available peripheral space rather than requiring a single large centralized gearbox, thereby reducing overall space requirements while maintaining the ability to drive multiple accessories efficiently

Inventive Principle:

Principle #1Segmentation

2Device complexity

If a single accessory gearbox is used to mechanically couple engine accessories to the turbine engine, then the structure is simpler, but power transmission efficiency decreases

Engineering Contradiction:

Improvegearbox structureVSAvoidpower transmission efficiency

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

The power transmission system is segmented into multiple gearboxes positioned at optimal locations around the engine. This allows for shorter power transmission paths from the engine core to each accessory, reducing energy losses. Each gearbox can be directly coupled to accessories with specific power requirements, minimizing unnecessary power transmission distances and improving overall efficiency

Inventive Principle:

Principle #1Segmentation

3Volume of moving object

If multiple gearboxes are used to reduce space requirements, then the engine design becomes more compact, but the device complexity increases

Engineering Contradiction:

Improvespace requirementsVSAvoidgearbox structure

Core Design Contradiction:

Volume of moving objectVSDevice complexity

Solution Approach 1:

Multiple gearboxes are merged into a coordinated system that shares common mounting structures and power input sources from the engine periphery. This merging approach allows the system to achieve compact space utilization while managing complexity through standardized interfaces and shared support structures, making the overall implementation more feasible

Inventive Principle:

Principle #5Merging (Combining)

4Loss of energy

If multiple gearboxes are used to improve power transmission efficiency, then energy loss is reduced, but device complexity increases

Engineering Contradiction:

Improvepower transmission efficiencyVSAvoidgearbox structure

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The multiple gearbox system is designed with dynamic power distribution capabilities, where each gearbox can independently receive and transmit power based on the specific requirements of connected accessories. This dynamic approach optimizes power transmission efficiency by matching power delivery to actual demand while managing complexity through modular, independently controllable units rather than a monolithic system

Inventive Principle:

Principle #15Dynamics

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 enhances power transmission efficiency and reduces space requirements for engine accessories, allowing for a more compact engine design and improved bypass flowpath efficiency.

Implementation Method 1

The layshaft is coupled to the inner tower shaft through an inner bevel gearing connection. The outer tower shaft is coupled to the layshaft through an outer bevel gearing connection. The intermediate gear system is configured to transfer mechanical power from the inner tower shaft to the layshaft and the outer tower shaft.

Methodology Applied

Scientific EffectMechanical power transmission through bevel gearing: Gear

Data Source

PatentUS20250154906A1Turbine engine accessory system with multiple gearboxes

Publication Date: 2025.05.15 RTX CORP

AI summary

An assembly is provided for a turbine engine. This assembly includes an inner tower shaft, a layshaft, an outer tower shaft, an intermediate gear system, an inner gearbox and an outer gearbox. The layshaft is coupled to the inner tower shaft through an inner bevel gearing connection. The outer tower shaft is coupled to the layshaft through an outer bevel gearing connection. The intermediate gear system is configured to transfer mechanical power from the inner tower shaft to the layshaft and the outer tower shaft. The intermediate gear system includes the inner bevel gearing connection and the outer bevel gearing connection. The inner gearbox is coupled to the intermediate gear system through the layshaft. The outer gearbox is coupled to the intermediate gear system through the outer tower shaft.