Aircraft Propulsion Gear Assembly for Selective Rotor Power Split

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Solution Overview

Problem

Existing aircraft propulsion systems face challenges in efficiently distributing power between different rotors, particularly in modes requiring simultaneous horizontal and vertical propulsion, which affects efficiency and handling capabilities.

Innovation Solution

The proposed aircraft assembly includes a carrier, first and second gear systems with sun, ring, and intermediate gears, and an idler gear, along with an electric machine and lock devices. This configuration allows for selective power distribution between the first and second propulsor rotors, enabling independent control of their rotations using the electric machine and lock system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If power is distributed to both propulsor rotors simultaneously, then total propulsion force is maximized, but control flexibility and handling capability deteriorate

Engineering Contradiction:
Improvetotal propulsion forceVSAvoidcontrol flexibility
Core Design Contradiction:
ForceVSAdaptability or versatility

Solution Approach 1:

The power distribution system is segmented into independent control paths for each propulsor rotor through separate brake mechanisms (first brake mechanism for first rotor, second brake mechanism for second rotor). This segmentation enables independent control of each rotor's braking force, allowing the system to maintain total propulsion force while providing flexible control adaptability for different flight modes and handling requirements.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If a simple gear connection is used between rotors, then device complexity is reduced, but the ability to independently control rotor rotation deteriorates

Engineering Contradiction:
Improvegear system complexityVSAvoidindependent rotor control
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

Brake mechanisms are introduced as intermediary devices between the gear-connected rotors. The first brake mechanism and second brake mechanism act as mediators that can independently apply braking force to each rotor while the rotors remain mechanically connected through the gear system. This intermediary approach enables independent control capability without requiring complete decoupling of the gear connection, thus maintaining a balance between device complexity and ease of operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If lock devices are added to prevent rotor rotation, then rotation control precision is improved, but device complexity increases

Engineering Contradiction:
Improverotation control precisionVSAvoidlock system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The brake mechanisms are designed to utilize the existing rotational motion and mechanical energy of the propulsor rotors themselves to generate the braking effect. Rather than requiring external power sources or complex active control systems, the brakes can use the rotor's own kinetic energy and mechanical connection to the gear system to achieve precise rotation control and locking when needed, thereby improving rotation control precision without proportionally increasing device complexity.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4282763B1Selective power distribution for an aircraft propulsion system
Publication Date: 2025.03.05 RTX CORP
  • EP4282763B1 patent drawingFigure 1
  • EP4282763B1 patent drawingFigure 2
  • EP4282763B1 patent drawingFigure 3A

AI summary

An assembly for an aircraft includes a carrier (90), a first gear system (86), a second gear system (88) and an idler gear (92). The first gear system (86) includes a first sun gear (94), a first ring gear (96) and a plurality of first intermediate gears (98). Each of the first intermediate gears (98) is between and is meshed with the first sun gear (94) and the first ring gear (96). Each of the first intermediate gears (98) is rotatably mounted to the carrier (90). The second gear system (88) includes a second sun gear (104), a second ring gear (106) and a plurality of second intermediate gears (108). Each of the second intermediate gears (108) is between and is meshed with the second sun gear (104) and the second ring gear (106). Each of the second intermediate gears (108) is rotatably mounted to the carrier (90). The idler gear (92) couples the first ring gear (86) to the second ring gear (88).