Elastic Coupling Arms for Aircraft Landing Gear Torque Transmission

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Solution Overview

Problem

Existing coupling devices between aircraft landing gear wheels and motor/reducer assemblies fail to provide optimal torque transmission due to axle deformations, leading to inefficiencies and increased complexity in wheel motorization.

Innovation Solution

An elastic coupling device with a star-shaped design featuring preloaded arms and U-section housings that allow for axial preload and flexibility, ensuring torque transmission despite axle deformations, while maintaining simplicity and ease of assembly and disassembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If metal springs are used to connect the drive ring to the wheel rim to absorb deformations, then the coupling device can accommodate axle deformations, but the torque transmission between the drive crown and the wheel is not optimal

Engineering Contradiction:
Improveaccommodation of axle deformationsVSAvoidtorque transmission efficiency
Core Design Contradiction:
Adaptability or versatilityVSPower

Solution Approach 1:

The coupling device is segmented into multiple rigid arms arranged radially around the drive crown, with each arm independently connected to the wheel rim through elastic elements. This segmentation allows each arm to independently accommodate deformations while maintaining rigid torque transmission paths, resolving the contradiction between deformation accommodation and torque transmission efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The coupling device combines rigid arms (for torque transmission) with elastic elements (for deformation accommodation), creating a composite structure that simultaneously achieves both optimal torque transmission and adaptation to axle deformations. The rigid-elastic combination allows each component to perform its specialized function without compromising the other.

Inventive Principle:
Principle #40Composite materials

2Power

If a complex coupling device is designed to ensure optimal torque transmission while accommodating deformations, then torque transmission is improved, but the complexity and duration of wheel mounting and dismounting operations increases

Engineering Contradiction:
Improvetorque transmission efficiencyVSAvoidwheel mounting and dismounting complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The coupling device is designed as a modular assembly of identical radial arms that can be independently installed or removed. This segmentation allows for simplified maintenance and assembly operations, as individual arms can be serviced without affecting the entire coupling device, thereby reducing overall complexity despite the sophisticated torque transmission capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The drive crown is merged with the radial arms to form an integrated rotating assembly, while the elastic elements serve as universal connectors between arms and wheel rim. This merging reduces the number of separate components and simplifies the mounting procedure, maintaining ease of wheel installation despite the advanced torque transmission mechanism.

Inventive Principle:
Principle #5Merging (Combining)

3Power

If a heavy coupling device is used to ensure rigid torque transmission, then torque transmission is improved, but the weight of the aircraft is increased

Engineering Contradiction:
Improvetorque transmission efficiencyVSAvoidaircraft weight
Core Design Contradiction:
PowerVSWeight of moving object

Solution Approach 1:

The coupling device employs thin elastic elements (such as elastic rings or flexible membranes) instead of heavy rigid connectors. These flexible components provide sufficient torque transmission while accommodating deformations, significantly reducing the weight compared to traditional rigid coupling mechanisms. The elastic elements maintain structural integrity under torque loads while being substantially lighter than solid metal alternatives.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The coupling device transitions from static rigid connections to dynamic elastic connections that adapt to deformation conditions. This dynamic approach allows the use of lighter elastic materials that can withstand torque transmission through elastic deformation, rather than requiring heavy rigid structures designed for worst-case static loads, thereby reducing overall weight while maintaining torque transmission efficiency.

Inventive Principle:
Principle #15Dynamics

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

The coupling device achieves efficient torque transmission between the motorization member and the wheel, minimizing weight increase and operational complexity, and allowing for easy replacement of wear parts, thus optimizing wheel motorization without affecting aircraft weight or maintenance operations.

Implementation Method 1

said arms are in the form of blades... said arms are sized so that, in the mounted position of said wheel on said landing gear, they are axially preloaded

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2837557B1Device for coupling a motor-driven landing gear wheel of an aircraft
Publication Date: 2016.06.15 AIRBUS OPERATIONS (SAS)
  • EP2837557B1 patent drawingFigure 1~2
  • EP2837557B1 patent drawingFigure 3
  • EP2837557B1 patent drawingFigure 4

AI summary

This elastic coupling device (7) between an aircraft landing gear wheel (3) and a coaxial drive element (6) of said wheel comprises a plurality of arms (9) rotationally fixed to said drive element on the side of a first radially inner end and adapted to be connected to said wheel (3) on the side of their opposite radially outer end, said arms (9) being substantially rigid in a plane perpendicular to the axis of rotation of the wheel and flexible in directions substantially transverse to said plane.