Counter-Rotating Gear Assembly With Direct Torque Transfer

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Solution Overview

Problem

Indirect drive turbine engines face inefficiencies in gear assemblies due to mechanical and thermal losses, limiting fan and turbine speed efficiency improvements.

Innovation Solution

A counter-rotating gear assembly design that eliminates the need for idler planet gears by using a spindle connected to both input shafts and an output shaft through gear meshes and bearing assemblies, allowing for direct torque transfer and improved durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If traditional gear assemblies with multiple gears are used, then speed reduction and torque multiplication are achieved, but mechanical and thermal losses increase reducing overall efficiency

Engineering Contradiction:

Improvemechanical and thermal lossesVSAvoidnumber of gears

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The patent combines multiple gear functions into a single planetary gear assembly where the sun gear, planet gears, and ring gear work together as an integrated unit. This merging of functions reduces the total number of separate gear components while maintaining the speed reduction and torque multiplication capabilities, thereby reducing mechanical and thermal losses.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The planetary gear assembly serves multiple functions simultaneously: it provides speed reduction, torque multiplication, and structural support for the turbine shaft. The fixed ring gear acts as both a gear element and a mounting structure, while the planet gears simultaneously transmit power and support radial loads, reducing the need for additional components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If multiple input shafts rotating in opposite directions are accommodated, then counter-rotation capability is achieved, but gear assembly complexity increases

Engineering Contradiction:

Improvecounter-rotation capabilityVSAvoidgear assembly structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Instead of using complex idler gear arrangements to achieve counter-rotation, the patent inverts the approach by directly coupling the two counter-rotating input shafts to the sun gear and ring gear respectively. The planetary gear system then naturally produces the desired counter-rotation output through its inherent mechanical advantage and gear ratio characteristics, simplifying the overall structure.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The planetary gear assembly acts as an intermediary mechanism that receives power from two counter-rotating input shafts and transfers it to a single output shaft. The planet gears serve as mediators that synchronize and combine the power from both input sources while maintaining the counter-rotation capability, eliminating the need for additional idler gears or complex synchronization mechanisms.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11118506B2Gear assembly for a turbo machine

Publication Date: 2021.09.14 GENERAL ELECTRIC CO

AI summary

A gear assembly for a turbo machine is provided. The gear assembly includes a first input shaft, a second input shaft, an output shaft, a fixed member, and a spindle. The spindle is extended along a spindle centerline axis. The first input shaft is drivingly connected to the spindle at a first interface. The second input shaft is drivingly connected to the spindle at a second interface. The spindle is connected to the fixed member providing a reactive force at a third interface. The spindle is connected to the output shaft at a fourth interface.