Cylindrical Fan Case with Monolithic Connecting Ring and Reinforcement

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Solution Overview

Problem

Conventional cylindrical fan cases for aircraft jet engines face challenges in achieving high rigidity while minimizing weight and reducing manufacturing costs, particularly due to the connection of angular sectors with flanges and screws, which increases weight and costs.

Innovation Solution

A cylindrical case design featuring a connecting ring body with an annular groove and a reinforcement body fitted to the groove, forming a monolithic structure that distributes reverse thrust loads effectively, using a Ti alloy reinforcement for high-load regions and an Al alloy for the connecting ring body, eliminating the need for lightening holes and reducing weight and manufacturing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If angular sectors are connected with flanges and screws to form the downstream end, then the structural integrity is improved, but the weight increases

Engineering Contradiction:

Improvestructural integrityVSAvoidweight

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The patent merges multiple angular sectors into a monolithic connecting ring body, eliminating the need for separate flanges and screws to connect them. This integration maintains structural integrity while significantly reducing the weight associated with multiple fastening components.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The reinforcement body is fitted inside the connecting ring body, creating a nested structure where the Ti alloy reinforcement body is positioned within the Al alloy connecting ring body. This nested configuration provides structural strengthening without adding external weight.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Reliability

If angular sectors are connected with flanges and screws, then the assembly is secure, but the manufacturing cost increases

Engineering Contradiction:

Improveassembly securityVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

By combining multiple angular sectors into a single monolithic connecting ring body, the patent eliminates the need for multiple fastening operations and component assemblies, thereby reducing manufacturing complexity and cost while maintaining assembly security.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent segments the structural reinforcement function from the connecting function by introducing a separate reinforcement body that is fitted into the connecting ring body. This allows each component to be optimized and manufactured independently, then assembled with simple fitting rather than complex fastening.

Inventive Principle:

Principle #1Segmentation

3Weight of moving object

If lightening holes are formed in the Al alloy angular sector to reduce weight, then the weight decreases, but the manufacturing cost increases

Engineering Contradiction:

ImproveweightVSAvoidmanufacturing cost

Core Design Contradiction:

Weight of moving objectVSEase of manufacture

Solution Approach 1:

The patent combines the weight reduction function into the overall structural design by using a monolithic connecting ring body without requiring additional lightening holes. The monolithic structure achieves weight efficiency through its integrated form rather than through post-processing modifications.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent uses composite material construction with Al alloy for the connecting ring body and Ti alloy for the reinforcement body. This composite approach provides optimal strength-to-weight ratio without requiring lightening holes, as the material selection itself achieves the weight reduction goal.

Inventive Principle:

Principle #40Composite materials

4Ease of manufacture

If a monolithic connecting ring body is used, then the manufacturing cost decreases, but the rigidity is insufficient

Engineering Contradiction:

Improvemanufacturing costVSAvoidrigidity

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The reinforcement body is nested inside the connecting ring body, creating a reinforced monolithic structure. This nested configuration provides the necessary rigidity and strength to the connecting ring body while maintaining the manufacturing simplicity of a monolithic design.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent employs composite materials with Al alloy for the connecting ring body and Ti alloy for the reinforcement body. The Ti alloy reinforcement body provides enhanced rigidity and strength, compensating for the simplicity of the monolithic design while maintaining manufacturing cost efficiency.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS10294961B2Cylindrical case

Publication Date: 2019.05.21 IHI CORP

AI summary

A cylindrical case main body, and a connecting ring body fitted and fixed to a first end of the case main body and having an annular groove open in the centrifugal direction, are provided. The connecting ring body has a notch open to a side opposite to a second end of the case main body. Into the notch of the connecting ring body, a reinforcement body is fitted, and the reinforcement body has an arc-shaped groove continuing to the annular groove of the connecting ring body in a state where the reinforcement body is fitted into the notch of the connecting ring body. In addition to attaining high rigidity, reduction in weight and reduction in manufacturing cost can also be achieved.