Jet Engine Auxiliary Gear Drive Extension Shaft Design

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Solution Overview

Problem

Existing auxiliary gear mechanisms for engines require significant installation space and weight due to the need for separate auxiliary transmission shafts and numerous gear wheels, making them complex and costly.

Innovation Solution

The auxiliary gear mechanism features a detachable extension shaft that can be coaxially connected to the drive shaft, eliminating the need for a separate auxiliary transmission shaft, reducing the number of gear wheels, and allowing for easier detachment and maintenance of auxiliary units like generators.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate auxiliary transmission shafts and numerous gear wheels are used to drive auxiliary units, then reliable power transmission is achieved, but installation space and weight increase significantly

Engineering Contradiction:
Improvepower transmission reliabilityVSAvoidinstallation space
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The extension shaft integrates multiple functions: it serves as both a transmission shaft and a mounting structure for auxiliary units. The shaft combines power transmission capability with direct mounting surfaces, eliminating the need for separate transmission shafts and reducing the number of gear wheels while maintaining reliable power transmission to all auxiliary units.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The extension shaft is designed as a multi-functional component that simultaneously performs power transmission, structural support, and mounting functions for multiple auxiliary units. This universal component replaces several specialized components (multiple transmission shafts and gear wheels) with a single integrated shaft, reducing overall system complexity and space requirements.

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

2Reliability

If separate auxiliary transmission shafts and numerous gear wheels are used, then power transmission to multiple auxiliary units is achieved, but the system weight increases

Engineering Contradiction:
Improvepower transmission capabilityVSAvoidtransmission system weight
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

The extension shaft merges the functions of multiple transmission shafts and gear wheels into a single integrated component. By combining power transmission and auxiliary unit mounting functions in one shaft, the total material usage and system weight are reduced while maintaining the capability to drive multiple auxiliary units reliably.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If auxiliary units are mounted on separate auxiliary transmission shafts, then proper power transmission is achieved, but the number of components and complexity increase

Engineering Contradiction:
Improvepower transmissionVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The extension shaft combines multiple transmission functions and mounting functions into a single component, reducing the total number of parts. Instead of having separate transmission shafts and gear wheels for each auxiliary unit, one integrated shaft serves all units, simplifying the overall system architecture while maintaining reliable power transmission.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The extension shaft is designed as a universal component that can transmit power to multiple different auxiliary units simultaneously. This multi-functional shaft replaces several specialized single-purpose components, reducing system complexity and the number of parts that need to be manufactured, assembled, and maintained.

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

4Stability of the object's composition

If auxiliary units are permanently installed on transmission shafts, then structural stability is achieved, but maintenance and replacement become difficult

Engineering Contradiction:
Improvestructural stabilityVSAvoidauxiliary unit maintenance
Core Design Contradiction:
Stability of the object's compositionVSEase of repair

Solution Approach 1:

The system is segmented into modular components where auxiliary units can be independently removed from the extension shaft. The shaft features discrete mounting positions that allow individual auxiliary units to be detached without affecting the stability or operation of other units, enabling easy maintenance and replacement while maintaining structural integrity during operation.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2565422B1Auxiliary geared drive for a jet engine
Publication Date: 2019.10.30 ROLLS ROYCE DEUT LTD & CO KG
  • EP2565422B1 patent drawingFigure 1~2
  • EP2565422B1 patent drawingFigure 3~4

AI summary

The auxiliary equipment gear device (9) has a drive shaft that is actively connected to the main shaft (11) of the engine (1). An extension shaft is provided that is coaxial to the drive shaft and is operatively connected to the releasable drive shaft, where an auxiliary power unit (39) is arranged in the detachable manner on the extension shaft. The extension shaft is detachable, through a relative translational motion, from the drive shaft and an auxiliary unit of the extension shaft.