Annular Flange Angular Mistake-Proofing via Hollow Portion Radius

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Solution Overview

Problem

In turbomachines, annular flanges can be incorrectly assembled due to angular misalignment, leading to potential operational failures as they may not be securely fastened by bolts, resulting in unintended movement and severe consequences.

Innovation Solution

The implementation of angular mistake-proofing means on annular flanges, where the bottom of hollow portions have a radius that is either smaller or larger than the circle tangential to the bolt orifices, preventing incorrect assembly by blocking the path of fastener bolts if the flanges are offset, ensuring correct angular positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the flange uses alternating solid portions and hollow portions to reduce weight, then the weight of the flange is reduced, but the risk of angular misalignment during assembly increases

Engineering Contradiction:

Improveweight of flangeVSAvoidangular alignment reliability

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The bottom of the hollow portion acts as an intermediary element that mediates between the flange structure and the bolt insertion process. It serves as a physical barrier that prevents incorrect assembly by blocking the bolt path when angular misalignment occurs, while not affecting the weight reduction function of the hollow portion.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The flange structure itself provides the mistake-proofing function through its own geometry. The bottom of the hollow portion is positioned to automatically prevent incorrect assembly without requiring additional separate components or complex alignment mechanisms.

Inventive Principle:

Principle #25Self-service

2Reliability

If the bottom of hollow portions is modified to provide mistake-proofing, then angular alignment reliability is improved, but the weight of the flange increases

Engineering Contradiction:

Improveangular alignment reliabilityVSAvoidweight of flange

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The invention modifies the geometric parameters of the hollow portion by positioning its bottom at a specific radius relative to the bolt orifice circle. This parameter change creates the mistake-proofing function while minimizing weight impact, as the modification is localized and does not require substantial material addition.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the radius of hollow portion bottom is changed to prevent bolt insertion, then assembly reliability is improved, but rotary unbalance may occur

Engineering Contradiction:

Improveassembly reliabilityVSAvoidrotary balance

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The hollow portion bottom is positioned asymmetrically relative to the bolt orifices to create the mistake-proofing function. This asymmetric positioning is deliberate and controlled, and any resulting unbalance can be compensated during the balancing process without affecting the reliability function.

Inventive Principle:

Principle #4Asymmetry

Data Source

PatentUS9039351B2Annular flange for fastening a rotor or stator element

Publication Date: 2015.05.26 SAFRAN AIRCRAFT ENGINES SAS

AI summary

A radial annular flange of a rotor or stator element of a turbomachine including, at an inner/outer periphery, alternating solid portions and hollow portions, the solid portions including orifices for passing fastener bolts. The flange in the bottom of at least one hollow portion has a radius relative to the axis of the turbomachine that is less/greater than the radius of a circle that is tangential to the outsides/insides of the orifices for passing bolts through the solid portions.