Eccentric Gearbox Propulsion System for Aircraft

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Solution Overview

Problem

Commercial aircraft require significant propulsion energy due to their weight, leading to large propulsion systems that harm aerodynamics and increase fuel consumption, particularly in the direction perpendicular to the propeller axis.

Innovation Solution

A propeller propulsion system with electric motors and a gearbox where the input shaft is eccentric to the output shaft, allowing the motors to be integrated behind the gearbox, reducing the system's diameter and improving aerodynamics by arranging the motors in a sequential rather than parallel configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If multiple electric motors are connected in parallel to drive the propeller, then the propulsion system can provide sufficient power for heavy aircraft, but the diameter of the propulsion system increases significantly

Engineering Contradiction:
Improvepropulsion powerVSAvoidpropulsion system diameter
Core Design Contradiction:
PowerVSArea of stationary object

Solution Approach 1:

The patent transitions from a parallel arrangement (increasing diameter in the horizontal plane) to a sequential arrangement along the propeller axis (utilizing the vertical dimension). Multiple electric motors are connected in series along the input shaft rather than in parallel, which reduces the propulsion system's diameter while maintaining the required propulsion power through cumulative torque transmission.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The electric motors are nested sequentially along the input shaft, with each motor integrated into the space occupied by the previous motor's components. This nesting arrangement allows multiple motors to be compacted into a smaller radial envelope, reducing the overall propulsion system diameter while preserving the power transmission capability through the shared input shaft.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Power

If a large propulsion system is used to move heavy aircraft, then sufficient propulsion energy can be provided, but the aerodynamics of the aircraft deteriorates and fuel consumption increases

Engineering Contradiction:
Improvepropulsion energyVSAvoidaerodynamic drag
Core Design Contradiction:
PowerVSObject-affected harmful factors

Solution Approach 1:

By reconfiguring the motor arrangement from parallel to sequential along the propeller axis, the patent reduces the radial footprint of the propulsion system. This dimensional change minimizes the interference with airflow over the wing, thereby reducing aerodynamic drag and improving overall aircraft efficiency while maintaining the necessary propulsion energy output.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Productivity

If the electric motors are arranged in parallel, then each motor can contribute independently to propulsion, but the height and width of the propulsion system become significant

Engineering Contradiction:
Improvepropulsion efficiencyVSAvoidpropulsion system width
Core Design Contradiction:
ProductivityVSLength of stationary object

Solution Approach 1:

The patent redistributes the motors from a parallel configuration (spreading width and height) to a sequential configuration along the propeller axis. This dimensional transformation consolidates the propulsion system's footprint in the radial direction while extending it axially, thereby reducing width and height without compromising the cumulative propulsion efficiency contributed by each motor.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 reduces the aircraft's aerodynamic drag and fuel consumption by minimizing the system's height and diameter, enhancing propulsion efficiency.

Implementation Method 1

a gearbox having an output shaft to which the propeller is mechanically coupled and having an input shaft to which the plurality of electric motors is mechanically coupled

Methodology Applied
Scientific EffectGear mechanism: Gear

Data Source

PatentEP4122830B1Propulsion system with propeller for aircraft
Publication Date: 2024.05.01 AIRBUS OPERATIONS (SAS)
  • EP4122830B1 patent drawingFigure 1~2
  • EP4122830B1 patent drawingFigure 3~4

AI summary

An aircraft propeller propulsion system comprises a propeller (201), a plurality of electric motors (203) and a gearbox (202). The gearbox (202) has an output shaft (221) to which the propeller (201) is mechanically coupled and has an input shaft (224) to which the plurality of electric motors (203) is mechanically coupled, the input shaft (224) being eccentric with respect to the output shaft (221). All the electric motors (203) are mechanically coupled one after the other along the input shaft (224) in such a way that the electric motors (203) are at least partially integrated into a space, on the other side of the gearbox (202) relative to the propeller (201), left free by the eccentricity between the input shaft (224) and the output shaft (221). Thus, the diameter of the propulsion system in a plane perpendicular to the axis of rotation of the propeller (201) is reduced.The aircraft's aerodynamics and fuel consumption are improved.