Avionic LRU Housing with Electrically-Routed Ceramic Walls

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Solution Overview

Problem

Avionic Line Replaceable Units (LRUs) in aircraft face reliability issues due to structural compromise of electrical interconnections under high temperature and thermal cycling conditions, leading to increased maintenance costs and complexity.

Innovation Solution

The development of high temperature avionic LRUs with electrically-routed housing walls and hermetic bonding materials, reducing reliance on organic materials and incorporating ceramic substrates for enhanced temperature tolerance and reliability, along with modular designs for improved flexibility and modularity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional organic materials and solder interconnections are used in LRUs, then manufacturing cost and ease of manufacture are improved, but reliability under high temperature and thermal cycling conditions deteriorates

Engineering Contradiction:

Improvereliability under high temperature and thermal cyclingVSAvoidease of manufacture

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the material parameters by replacing organic materials with inorganic materials (ceramics, metals, glasses) that have higher temperature stability and resistance to thermal cycling, thereby improving reliability while maintaining manufacturability through established inorganic material processing techniques

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite material structures combining inorganic materials (ceramic substrates, metal housings, glass seals) to create LRUs that withstand high temperature environments while maintaining structural integrity and electrical functionality, resolving the contradiction between reliability and ease of manufacture

Inventive Principle:

Principle #40Composite materials

2Reliability

If high temperature solders are used to mitigate LRU failure modes, then reliability under elevated temperature is improved, but temperature tolerance only increases modestly and lead content increases

Engineering Contradiction:

Improvetemperature toleranceVSAvoidlead content and limited temperature increase

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent fundamentally changes the material composition by eliminating lead-based solders and organic materials, replacing them with inorganic materials that provide both high temperature tolerance and environmental compliance, simultaneously improving reliability while reducing harmful factors

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent extracts and removes harmful substances (lead, organic materials) from the LRU construction, replacing them with safe inorganic alternatives that provide enhanced temperature tolerance without the drawbacks of conventional high-temperature solders

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If LRUs are remotely located from high temperature environments, then temperature tolerance is improved, but system cost and complexity increase

Engineering Contradiction:

Improvetemperature toleranceVSAvoidsystem cost and complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Instead of remotely locating LRUs from high temperature environments, the patent inverts the approach by making the LRUs themselves thermally resistant through inorganic materials, allowing them to operate directly in high temperature environments near engines, thereby reducing system complexity and cost

Inventive Principle:

Principle #13The other way round (Inversion)

4Reliability

If inorganic materials are used to replace organic materials, then temperature tolerance and reliability are improved, but manufacturing complexity may increase

Engineering Contradiction:

Improvetemperature tolerance and reliabilityVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple functions into the inorganic material structure itself, where the ceramic substrate provides both mechanical support and electrical routing, and the inorganic bonding materials provide both structural bonding and hermetic sealing, thereby improving reliability while managing manufacturing complexity through functional integration

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS10044175B1High temperature avionic line replaceable units and aircraft systems containing the same

Publication Date: 2018.08.07 HONEYWELL INTERNATIONAL INC

AI summary

Avionic LRUs having increased temperature tolerances and other desirable properties are provided, as are aircraft systems containing such high temperature avionic LRUs. In one embodiment, the avionic LRU includes at least one microelectronic device and an LRU housing, which contains an enclosed cavity in which the microelectronic device is located. The LRU housing further includes an electrically-routed housing wall having an inner principal surface or frontside, which partially bounds the enclosed cavity and to which the microelectronic device is bonded or attached. The avionic LRU further includes a first LRU connector interface having a first LRU terminal array. The first LRU terminal array projects from the LRU housing and is electrically coupled to the microelectronic device through the electrically-routed housing wall. The LRU connector interface is configured to matingly engage the receptacle connector interface to support LRU operation when the LRU is removably mounted to the avionic LRU receptacle.