Aircraft Wheel Coupling with Telescopic Rods and Belleville Washers

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Solution Overview

Problem

Aircraft undercarriage components face high stresses during landings and take-offs, leading to wheel rim deformation and axis misalignment, which existing coupling means, such as heavy helical springs, are unable to effectively absorb, making them unsuitable for aircraft use.

Innovation Solution

A device with ball-jointed connecting members extending between the wheel rim and crown, allowing angular offset and varying length under force, enabling rotational movement transmission while accommodating deformations and displacements, utilizing telescopic connecting rods with Belleville washers for enhanced flexibility and energy dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If heavy helical springs are used as coupling means, then deformation absorption capability is improved, but device weight increases making it unsuitable for aircraft

Engineering Contradiction:
Improvedeformation absorption capabilityVSAvoidcoupling device weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The connecting members are designed with variable length capability through telescopic structures with Belleville washers, allowing the coupling device to dynamically adapt its geometry to absorb wheel deformations. This dynamic adjustment mechanism provides effective deformation absorption without requiring heavy spring structures, thus resolving the contradiction between reliability and weight.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the physical parameters of the connecting members by allowing their length to vary under applied forces. The Belleville washers enable controlled length variation and energy dissipation, providing deformation absorption capability comparable to heavy springs but with significantly reduced weight, making the coupling device suitable for aircraft applications.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If rigid coupling means are used, then structural simplicity is improved, but ability to absorb wheel axis displacement and rim deformation is worsened

Engineering Contradiction:
Improvecoupling structure simplicityVSAvoidaxis misalignment absorption capability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The connecting members incorporate variable length mechanisms with Belleville washers that allow the structure to dynamically adjust its configuration in response to wheel deformations and axis displacements. This dynamic capability enables the coupling device to accommodate misalignments while maintaining a relatively simple overall structure, resolving the contradiction between structural simplicity and adaptability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The Belleville washers act as intermediary elements between the rigid connecting members, enabling length variation and energy dissipation. This intermediary mechanism allows the coupling device to absorb axis displacements and rim deformations without requiring complex articulated structures, thus maintaining structural simplicity while improving adaptability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If variable length connecting members with Belleville washers are used, then deformation absorption and energy dissipation are improved, but device complexity increases

Engineering Contradiction:
Improvedeformation and energy absorption capabilityVSAvoidcoupling mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The connecting members with Belleville washers perform multiple functions simultaneously: they transmit rotational movement, absorb deformations through length variation, and dissipate energy through the Belleville washer mechanism. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity while improving reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The invention merges the functions of deformation absorption and energy dissipation into a single integrated mechanism using Belleville washers within the connecting members. This combination provides enhanced reliability without proportionally increasing device complexity, as the same structural elements perform multiple protective functions.

Inventive Principle:
Principle #5Merging (Combining)

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 device allows for significant deformation and axis offset absorption, providing increased freedom and reducing mechanical stress, while maintaining rotational movement transmission and attenuating startup jerks through energy dissipation, making it suitable for aircraft landing gear.

Implementation Method 1

each connecting member has a length which varies under the effect of a force undergone by the connecting member against an internal dissipative force

Methodology Applied
Scientific EffectInternal dissipative force: Friction

Data Source

PatentEP2524816B1Device for rotational coupling of a crown gear to a wheel and aircraft landing gear provided with such a device
Publication Date: 2015.07.01 SAFRAN LANDING SYSTEMS
  • EP2524816B1 patent drawingFigure 1
  • EP2524816B1 patent drawingFigure 2
  • EP2524816B1 patent drawingFigure 3

AI summary

The invention relates to a coupling device (32) for rotating a wheel (10) to a drive ring (31) of the wheel (10) mounted to rotate coaxially with the wheel (10). According to the invention, the device (32) comprises a plurality of connecting members (60), each extending in a direction contained in a plane perpendicular to the axis of rotation and making an angle with a radial direction, the connecting members (60) being spherically connected on one side to the wheel (10) and on the other side to the ring (31).