Tubular Element Junction Locks for Axial Compressor Casing

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Solution Overview

Problem

The existing connection systems for axial compressor casings in turbojet engines are bulky due to large bolts required to handle circumferential forces, making assembly and disassembly difficult and increasing weight and cost, while also risking bolt breakage.

Innovation Solution

A system using junction locks with complementary shapes and collars to distribute friction and forces more efficiently, reducing the number of bolts needed and allowing for segmented fastening to handle torsional forces, thereby minimizing flange size and weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If large diameter bolts are used to handle circumferential forces from compressor blade breakage, then the connection strength is improved, but the radial size of the flanges increases making assembly and disassembly difficult

Engineering Contradiction:

Improveconnection strengthVSAvoidassembly and disassembly ease

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The connection system is segmented into multiple independent locking elements distributed around the flange circumference. Each locking element handles local forces independently, allowing the use of smaller, more manageable components rather than requiring large bolts that span the entire flange diameter.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Locking elements act as intermediary components between the two flanges, providing a mechanical interlocking mechanism that distributes circumferential forces across multiple contact points. This intermediary structure eliminates the need for large bolts by creating a distributed force transmission path through the locking elements and cavities.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Strength

If large diameter bolts are used to handle circumferential forces, then the connection strength is improved, but the weight and cost of the connection system increase

Engineering Contradiction:

Improveconnection strengthVSAvoidconnection system weight

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The connection system is divided into multiple smaller locking elements rather than using fewer large bolts. This segmentation reduces the weight of individual components while maintaining overall connection strength through distributed force handling across multiple elements.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The design changes the connection parameters from large-diameter bolts to smaller locking elements with complementary cavity geometries. This parameter change optimizes the strength-to-weight ratio by using geometry-based interlocking rather than mass-based fastening.

Inventive Principle:

Principle #35Parameter changes

3Strength

If large diameter bolts are used to handle circumferential forces, then the connection strength is improved, but the number of bolts required increases making disassembly time-consuming

Engineering Contradiction:

Improveconnection strengthVSAvoiddisassembly time

Core Design Contradiction:

StrengthVSLoss of time

Solution Approach 1:

Multiple locking elements are merged into an integrated system where the cavities and locking elements work together as a unified mechanical interlocking mechanism. This merging reduces the total number of discrete fastening components compared to using multiple large bolts, thereby reducing assembly and disassembly time.

Inventive Principle:

Principle #5Merging (Combining)

4Strength

If flange outside diameter is increased to accommodate large bolts, then the connection strength is improved, but the radial size increases causing interference with external elements

Engineering Contradiction:

Improveconnection strengthVSAvoidflange radial area

Core Design Contradiction:

StrengthVSArea of stationary object

Solution Approach 1:

The connection system uses segmented locking elements that fit into corresponding cavities, distributing the connection function around the flange circumference. This segmentation allows for a smaller overall flange diameter while maintaining connection strength through multiple distributed contact points rather than requiring a large diameter to accommodate big bolts.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The connection mechanism transitions from a radial dimension solution (large bolts requiring large flange diameter) to an axial dimension solution (locking elements engaging in the axial direction within cavities). This dimensional change allows strong connections with smaller radial footprint, eliminating interference with external elements.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP1939409B1System for connecting two roughly tubular elements, casing containing such a system and use thereof

Publication Date: 2009.09.30 TECHSPACE AERO

Figure 1~2
Figure 3~4

AI summary

The system has fixing elements including a junction latch (210) i.e. trapezoidal sectioned solid prism, housed in a cavity (211) formed by two assembled circular flanges (203, 204). The cavity and the latch have partially complementary shape, where the latch has projections (212) provided with fixation units (213). A collar (214) has lateral surfaces (215a, 215b) that are arranged for being supported on proximal surfaces (203p, 204p) of the circular flanges. The collar has fixation units (216) that are complementary to the units (213) of the projections of the latch.