Eccentric Shaft and Sleeve Assembly for Hole Play Compensation

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Solution Overview

Problem

Existing connecting devices for mechanical parts in aircraft assembly struggle to quickly and cleanly compensate for play due to imperfect geometries and misalignments, requiring adjustment or drilling operations.

Innovation Solution

A connecting device featuring an eccentric shaft and sleeve with adjustable tolerance, allowing for rotational positioning to compensate for play between mechanical parts, which is then locked using blocking elements, eliminating the need for adjustments or drilling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional connecting devices are used to connect mechanical parts with play, then connection is achieved, but adjustment operations or drilling are required which increases assembly time and complexity

Engineering Contradiction:
Improveassembly speedVSAvoidassembly simplicity
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The patent applies parameter changes by using an eccentric shaft and eccentric sleeve with adjustable relative positioning. The eccentric sleeve can be rotated on the eccentric shaft to adjust the position of the second cylindrical section relative to the first, allowing the connection device to compensate for play of several millimeters without requiring adjustment operations or drilling. This changes the geometric parameters of the connection to accommodate variations in hole positioning.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If conventional connecting devices are used for mechanical parts with imperfect geometries, then connection is achieved, but drilling operations are required which complicates the assembly process

Engineering Contradiction:
Improvehole alignment toleranceVSAvoidassembly process simplicity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent applies dynamics by making the eccentric sleeve rotatable on the eccentric shaft during assembly. This dynamic adjustment capability allows the second cylindrical section to be positioned to match the actual positioning of the second hole, compensating for imperfect geometries and misalignments. The blocking elements then freeze this adjusted position, transforming the dynamic adjustment into a static secure connection without requiring drilling.

Inventive Principle:
Principle #15Dynamics

3Manufacturing precision

If adjustable tolerance mechanism is added to compensate for play, then connection accuracy improves, but device complexity increases

Engineering Contradiction:
Improveconnection accuracyVSAvoidconnecting device structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies the nested doll principle by placing the eccentric sleeve inside the eccentric shaft. The eccentric sleeve is received within the eccentric shaft in a nested configuration, where the inner cylindrical surface of the sleeve interacts with the second cylindrical section of the shaft. This nesting approach provides the adjustable tolerance mechanism while maintaining a compact and relatively simple overall structure, as the adjustment mechanism is contained within the existing cylindrical components rather than adding external complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

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

Enables a quick and clean assembly by compensating for play without adjustments or drilling, ensuring a secure and efficient connection of preassembled modules within the aircraft fuselage.

Implementation Method 1

an eccentric shaft comprising at least a first cylindrical section intended to be inserted into a circular hole of a first of said mechanical parts and a second cylindrical section, said first and second cylindrical sections having different axes of revolution; and an eccentric sleeve comprising at least one hollow cylinder provided with an outer cylindrical surface and an inner cylindrical surface, the outer cylindrical surface being intended to be inserted into a circular hole of the second of said mechanical parts and the inner cylindrical surface being intended to receive the second cylindrical section of the eccentric pin, said internal and external cylindrical surfaces having different axes of revolution

Methodology Applied
Scientific EffectEccentric: Excentric

Data Source

PatentEP3623646B1Linking device with single shearing provided with an off-centre axis and an off-centre sleeve, mechanical assembly comprising such a device and assembly method
Publication Date: 2022.11.09 AIRBUS (SAS)
  • EP3623646B1 patent drawingFigure 1
  • EP3623646B1 patent drawingFigure 2
  • EP3623646B1 patent drawingFigure 3~7

AI summary

- The linking device (1) comprises an eccentric shaft (2) and an eccentric sleeve (10) intended to be mounted on the eccentric shaft (2) so as to allow, by an appropriate rotational positioning of the eccentric sleeve (10) on the eccentric shaft (2), the compensation of any play between superimposed circular holes (T1, T2) of the mechanical parts (P1, P2) to be linked together by means of said linking device (1), the linking device (1) also comprising locking elements (16, 27) capable of locking the eccentric shaft (2) and the eccentric sleeve (10) in rotation, said linking device (1) thus making it possible to generate a fast, clean connection capable of locally compensating for play.