Aircraft Rotor Hub Power Transmission via Blade Tips

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Solution Overview

Problem

Conventional aircraft rotor systems have large rotor hubs that reduce efficiency and increase weight due to the need for large gearboxes and drive shafts, and they are prone to single-point failures, which can decrease safety.

Innovation Solution

The rotor system design features a hub that is rotated by the rotor blades, eliminating the need for a traditional drive system, allowing for a smaller hub size, increased usable flow area, and redundancy in power transmission through an externally driven rim and multiple power sources.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If conventional drive systems with large gearboxes and drive shafts are used to power the rotor hub, then the rotor hub can be adequately powered, but the hub size increases and usable flow area decreases

Engineering Contradiction:

Improvepower transmission to rotor hubVSAvoidusable flow area of rotor assembly

Core Design Contradiction:

PowerVSArea of stationary object

Solution Approach 1:

The patent extracts the drive system components (gearbox and drive shaft) from the traditional hub location and relocates them to the rotor blade tips. This allows the hub to be minimized in size while still receiving power through the rotor blades themselves, thereby increasing the usable flow area of the rotor assembly.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of powering the hub directly and having the hub power the blades, the patent inverts the power transmission path by powering the blades at their tips and having the blades themselves rotate the hub. This reversal eliminates the need for large central drive components.

Inventive Principle:

Principle #13The other way round (Inversion)

2Power

If conventional drive systems with large gearboxes and drive shafts are used to power the rotor hub, then the rotor hub can be adequately powered, but the overall weight of the rotor assembly increases

Engineering Contradiction:

Improvepower transmission to rotor hubVSAvoidweight of rotor assembly

Core Design Contradiction:

PowerVSWeight of moving object

Solution Approach 1:

The patent removes the heavy gearbox and drive shaft components from the hub and relocates them to the rotor blade tips. This redistribution of mass reduces the overall weight of the rotor assembly while maintaining adequate power transmission capability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

By inverting the power transmission path to use the rotor blades as the power transmission medium rather than using separate drive shafts and gearboxes, the patent eliminates heavy mechanical components and reduces the overall weight of the rotor assembly.

Inventive Principle:

Principle #13The other way round (Inversion)

3Device complexity

If a single drive system is used to power the rotor assembly, then the structure is simpler, but the likelihood of single-point failure increases

Engineering Contradiction:

Improvestructure of drive systemVSAvoidlikelihood of rotor assembly failure

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent segments the power transmission system by distributing drive components across multiple rotor blade tips rather than using a single centralized drive system. This segmentation creates redundancy, as failure of one blade's drive system does not necessarily cause failure of the entire rotor assembly.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements redundancy in the power transmission system by having multiple independent drive systems at different blade tips. This beforehand cushioning ensures that if one drive system fails, the others can continue to operate, preventing catastrophic failure of the rotor assembly.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

4Ease of manufacture

If a large rotor hub is used to accommodate drive systems, then the drive components can be properly housed, but efficiency of the rotor assembly decreases

Engineering Contradiction:

Improvehousing of drive componentsVSAvoidefficiency of rotor assembly

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent extracts the drive components from the hub and places them at the rotor blade tips, where they can be housed in smaller, more efficient locations. This eliminates the need for a large hub that would block airflow and reduce rotor assembly efficiency.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

By inverting the power transmission path and using the rotor blades as the power transmission medium, the patent eliminates the need for a large hub to house drive components. The drive components are instead housed at the blade tips, minimizing interference with airflow and maximizing efficiency.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS11338915B2Rotor systems and methods

Publication Date: 2022.05.24 TEXTRON INNOVATIONS INC

AI summary

An aircraft rotor system including a hub having a hub axis about which the hub is configured to rotate; a plurality of rotor blades configured to extend from the hub and rotate about the hub axis, at least one of the rotor blades rotatable about a respective pitch change axis; wherein the hub is configured to be rotated about the hub axis only by the plurality of rotor blades. Another aspect includes a method of operating the rotor system.