Aircraft Shock Strut Titanium Cylinder and Composite Bearings

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Solution Overview

Problem

Aircraft shock struts used in landing gear require lighter materials to reduce weight, but these materials often suffer from premature wear, leading to increased maintenance costs due to frequent replacements.

Innovation Solution

The use of a titanium cylinder with non-metallic composite bearings, such as polyimide resin or polyketone thermoplastic materials, for sliding engagement between the piston and cylinder, which reduces wear and extends the lifespan of the shock strut.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If lighter weight materials are used in shock struts, then the weight of aircraft landing gear is reduced, but the components suffer from premature wear requiring frequent replacement

Engineering Contradiction:
Improveweight of shock strutVSAvoidwear resistance
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent applies composite materials by combining titanium cylinder with non-metallic composite bearings (such as polyimide resin or polyketone thermoplastic materials). This composite approach allows the structure to achieve both weight reduction from the titanium material and wear resistance from the specialized bearing materials, directly resolving the contradiction between lightweight design and durability

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the material parameters by selecting specific non-metallic composite materials (polyimide resin, polyketone thermoplastic) with optimized physical and chemical properties for the bearing components. These parameter changes enable the bearings to withstand wear while maintaining compatibility with titanium, thus improving reliability without sacrificing the weight benefits

Inventive Principle:
Principle #35Parameter changes

2Duration of action of stationary object

If non-metallic composite bearings are used with titanium cylinder, then wear is minimized and lifespan is extended, but manufacturing complexity increases

Engineering Contradiction:
Improvelifespan of shock strutVSAvoidmanufacturing complexity
Core Design Contradiction:
Duration of action of stationary objectVSEase of manufacture

Solution Approach 1:

The patent applies local quality by using non-metallic composite bearings specifically at the sliding engagement interfaces between the piston and cylinder, while maintaining titanium for the structural cylinder body. This localized application of specialized materials extends lifespan at critical wear points without requiring the entire shock strut to be manufactured with complex composite structures, thus balancing durability with manufacturability

Inventive Principle:
Principle #3Local quality

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

This configuration effectively reduces the weight of aircraft landing gear while minimizing wear on the titanium components, thereby decreasing maintenance costs and improving the durability of the shock struts.

Implementation Method 1

non-metallic composite bearings, such as polyimide resin or polyketone thermoplastic materials, for sliding engagement between the piston and cylinder, which reduces wear

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

minimizing wear on the titanium components, thereby decreasing maintenance costs and improving the durability of the shock struts

Methodology Applied
Scientific EffectWear resistance: Wear

Data Source

PatentEP1993907B2Aircraft shock strut having improved cylinder and bearings
Publication Date: 2019.01.02 GOODRICH CORP
  • EP1993907B2 patent drawingFigure 1
  • EP1993907B2 patent drawingFigure 2
  • EP1993907B2 patent drawingFigure 3~5

AI summary

An aircraft shock strut (12) includes a titanium cylinder (32) and a piston (30) telescopically movable within the titanium cylinder (32). A first bearing (40) is mounted to the piston (30), and includes a non-metallic bearing surface (50) for providing sliding engagement with the titanium cylinder (32). The aircraft shock strut (12) provides weight savings along with durability.