Pi-Shaped Aircraft Joint for Precise Bonded Plate Positioning

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Solution Overview

Problem

The existing joint configurations, such as those disclosed in US 8 403 586 A, require additional assembly operations and compromise strength by incorporating projections and slots for positioning, which is undesirable for aircraft structures aiming to reduce weight and maintain structural integrity.

Innovation Solution

A pi-shaped joint with a groove on a preform, featuring asymmetrical fitting shapes on the bottom face of the groove, allows for precise positioning of a plate member without increasing assembly operations or reducing strength, using adhesive bonding to connect the member to the preform and the joint.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a projection and slot are provided for positioning the plate member, then positioning accuracy is improved, but the number of assembly operations increases and strength is reduced

Engineering Contradiction:
Improvepositioning accuracyVSAvoidnumber of assembly operations
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The positioning function is merged with the groove structure itself. The fitting shape is formed directly on the bottom face of the groove, combining the positioning feature with the bonding interface, thereby eliminating the need for separate positioning projections and slots while maintaining positioning accuracy

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The groove bottom face serves multiple functions: it provides the bonding surface for adhesive application and simultaneously provides the fitting shape for positioning. This multi-functional design eliminates the need for separate positioning features, reducing assembly operations while maintaining positioning accuracy

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

2Manufacturing precision

If a projection and slot are provided for positioning the plate member, then positioning accuracy is improved, but strength is reduced

Engineering Contradiction:
Improvepositioning accuracyVSAvoidstructural strength
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The positioning function is merged with the groove structure itself. The fitting shape is formed directly on the bottom face of the groove, combining the positioning feature with the bonding interface, thereby eliminating the need for separate positioning projections and slots while maintaining positioning accuracy

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The fitting shape is formed in advance on the groove bottom face during groove formation, so that positioning capability is built into the structure before assembly. This preliminary action eliminates the need for additional positioning features that would compromise structural strength

Inventive Principle:
Principle #10Preliminary action

3Weight of moving object

If adhesive bonding is used to connect the member to the preform, then weight is reduced by eliminating fasteners, but positioning accuracy may be compromised

Engineering Contradiction:
Improvestructural weightVSAvoidpositioning accuracy
Core Design Contradiction:
Weight of moving objectVSManufacturing precision

Solution Approach 1:

An asymmetrical fitting shape is provided on the bottom face of the groove, which prevents rotational misalignment and ensures correct positioning of the plate member. The asymmetrical shape creates a unique fit that guides the member into the correct position, maintaining positioning accuracy while using adhesive bonding to eliminate fasteners and reduce weight

Inventive Principle:
Principle #4Asymmetry

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 high-accuracy positioning of members within the aircraft structure without additional assembly steps, maintaining structural integrity and reducing weight by eliminating the need for fasteners, while simplifying the assembly process.

Implementation Method 1

A plate member inserted into the joint is bonded using adhesive, and the joint is also bonded to a preform using adhesive. In this way, plate members are connected to a preform.

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentEP3015721B1Joint, and aircraft structure
Publication Date: 2021.07.14 MITSUBISHI HEAVY IND LTD
  • EP3015721B1 patent drawingFigure 1
  • EP3015721B1 patent drawingFigure 2
  • EP3015721B1 patent drawingFigure 3

AI summary

Provided is a joint and an aircraft structure wherein it is possible to position a member relative to a preform with high accuracy. A groove into which a plate member (30) is inserted is formed in a pi-shaped joint (20) provided on the preform (21), and the preform (21) and the plate member (30) are connected by being bonded. Moreover, a fitting shape (32A-1) into which the plate member (30) is fitted is formed on the pi-shaped joint (20) on the whole groove bottom face. Additionally, a fitting shape (32A-2) into which the plate member (30) is fitted is formed on a portion of the groove bottom face. Furthermore, fitting shapes (32B-1, 32B-2), into which the groove bottom face that is formed on the pi-shaped joint (20) is fitted, are formed on the surface of the plate material (30) that is fitted with the pi-shaped joint (20).