Hybrid Rotor Shell Offset Composite Drum Weight

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Solution Overview

Problem

Conventional compressor rotors with metal drums and dovetail fixings are heavy, costly to manufacture, and have uneven weight distribution, leading to inefficiencies in size and overall weight, as well as lengthy machining times.

Innovation Solution

A compressor rotor design featuring a composite drum with internal shells that have orifices for rotor blades, allowing for axial and circumferential alignment, with blades fixed via riveting or welding, and a method of assembly involving axial positioning of shells and blades, reducing weight and manufacturing time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a metal drum with dovetail fixings is used, then structural strength is ensured, but weight increases and manufacturing time increases

Engineering Contradiction:
Improvestructural strengthVSAvoidrotor weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent applies composite materials by combining a metal drum with composite shells that have dovetail fixings. This hybrid approach allows the drum to maintain its structural strength while the composite shells reduce overall weight compared to a fully metal construction. The composite shells are attached to the metal drum using lightweight fastening methods.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The rotor is segmented into distinct components: a metal drum, composite shells, and rotor blades. Each component can be manufactured separately using optimal processes for its material type, then assembled together. The shells are positioned axially overlapping the drum with circumferential alignment, creating modular sections that reduce total weight while maintaining structural integrity.

Inventive Principle:
Principle #1Segmentation

2Reliability

If dovetail fasteners are used to attach blades, then blade fixation is achieved, but manufacturing cost and time increase

Engineering Contradiction:
Improveblade fixationVSAvoidmanufacturing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The dovetail fixings are pre-formed as integral features of the composite shells during shell manufacturing, rather than being cut or machined separately. This preliminary action eliminates time-consuming post-manufacturing machining operations and reduces assembly time, as the shells are ready for immediate attachment to the drum and blades.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The shell structure merges multiple functions into a single component: it provides structural support, contains the dovetail fixings for blade attachment, and serves as a mounting surface for the rotor blades. This consolidation eliminates the need for separate fixing mechanisms and reduces the number of manufacturing steps.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If a single-piece rotor is manufactured, then assembly simplicity is achieved, but manufacturing time increases and flexibility is reduced

Engineering Contradiction:
Improveassembly simplicityVSAvoidmanufacturing speed
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The rotor is divided into separable components (drum, shells, blades) that can be manufactured in parallel using different processes optimized for each material type. The metal drum can be forged or 3D printed while composite shells are molded simultaneously, then assembled together in a final step. This segmentation enables flexible manufacturing and faster production cycles.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The manufacturing approach changes from a single-piece monolithic process to a multi-component assembly process. This parameter change allows for parallel production, selective manufacturing methods (3D printing, molding, forging), and optimized process parameters for each component material, significantly improving overall productivity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3715638B1Hybrid rotor with external shell offset against the composite annular wall
Publication Date: 2024.04.24 SAFRAN AERO BOOSTERS SA
  • EP3715638B1 patent drawingFigure 1~2
  • EP3715638B1 patent drawingFigure 3~5
  • EP3715638B1 patent drawingFigure 6~7

AI summary

An axial turbomachine compressor, such as an aircraft turbojet engine, with a rotor comprising: a drum (140), substantially axisymmetric in shape and made of composite material, the drum having a radially external surface (141); at least one annular row of rotor blades (124), the rotor (112) comprising at least one shell (150) for attaching the rotor blades (124) to the drum (140), the shell (150) being attached to the drum (140) on its external face (141) and forming a contact surface between two circumferentially adjacent rotor blades (124). The blade (124) may be provided with a mounting platform (126) in contact with and attached to an internal surface (143) of the drum (140).