Composite Rotor Structure With Curved Webs for Low Mass and Stiffness

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Solution Overview

Problem

Traditional electric motor designs face challenges with high mass, insufficient stiffness, and inability to meet structural requirements for temperature and vibration, leading to inefficiencies and increased complexity and cost.

Innovation Solution

A lightweight rotor design with a composite structure featuring a central hub, outer ring assembly, and back-to-back curved webs made of carbon fiber and epoxy, which provides improved stiffness and torque carrying capacity, and is fabricated using topology optimization and composite manufacturing techniques.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If traditional electric motor rotor designs are used, then structural strength and stiffness can be maintained, but the mass is high and efficiency is reduced

Engineering Contradiction:
Improverotor massVSAvoidstructural strength
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The patent applies composite materials by replacing traditional metallic rotor components with carbon fiber reinforced polymer (CFRP) composite structures. The rotor includes a composite hub, composite outer ring, and composite webs made from carbon fiber layers impregnated with epoxy resin, achieving significant mass reduction while maintaining or improving structural strength and stiffness through the high strength-to-weight ratio of carbon composites.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent employs curved web structures connecting the hub to the outer ring, replacing traditional straight or radial support structures. The curved geometry optimizes stress distribution and enhances the torsional stiffness of the rotor, allowing for thinner, lighter web sections that maintain structural integrity while reducing mass.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Strength

If traditional metallic rotor structures are used, then structural integrity is maintained, but the stiffness to weight ratio is insufficient

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

Solution Approach 1:

The patent utilizes carbon fiber reinforced polymer composites throughout the rotor structure, including the hub, outer ring, and webs. These composite materials provide superior strength-to-weight and stiffness-to-weight ratios compared to traditional metals, maintaining structural integrity while achieving significant weight reduction for high-performance applications.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent employs multi-layered composite construction with fibers oriented in different directions to achieve three-dimensional structural integrity. The carbon fiber layers are stacked with varying orientations (0°, 90°, ±45°) to withstand multidirectional stresses, creating a structurally optimal design that maximizes strength while minimizing mass.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If conventional rotor designs are used, then manufacturing simplicity is maintained, but the ability to meet temperature and vibration structural requirements is insufficient

Engineering Contradiction:
Improvetemperature and vibration resistanceVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent divides the rotor into separable composite components including the hub, outer ring, and webs, which can be manufactured independently using automated composite layup and curing processes. These segments are then assembled using bonded joints or mechanical fasteners, allowing for simplified manufacturing and assembly while maintaining structural integrity under temperature and vibration conditions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent utilizes the anisotropic properties of composite materials by adjusting fiber orientation, layer thickness, and material composition to optimize performance for specific loading conditions. The composite structure can be tailored to withstand thermal expansion differences and vibration loads by controlling the directional properties of each composite layer.

Inventive Principle:
Principle #35Parameter changes

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

The design achieves weight reduction, enhanced mechanical stiffness, and improved efficiency by reducing mass while maintaining structural integrity at high temperatures and rotational speeds, with carbon composites offering dimensional stability and various options for temperature and cost requirements.

Implementation Method 1

back-to-back curved webs made of carbon fiber and epoxy

Methodology Applied
Scientific EffectComposite materials: Composite Materials

Implementation Method 2

an interior surface to which the hub flange is adhered and an exterior surface adhered to an inner edge of each of the back-to-back curved webs

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 3

each of the back-to-back curved webs exerts a radial spring force on at least one of the central hub and the outer ring assembly

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 4

The magnetic elements are configured to interact with the magnetic flux to drive unitary rotation of the rotor-shaft assembly

Methodology Applied
Scientific EffectElectromagnetic interaction: Electromagnetic Induction

Data Source

PatentEP4475396A1Lightweight rotor design with composite structure
Publication Date: 2024.12.11 HAMILTON SUNDSTRAND CORP
  • EP4475396A1 patent drawingFigure 1
  • EP4475396A1 patent drawingFigure 2~3
  • EP4475396A1 patent drawingFigure 4~5

AI summary

A rotor (130) is provided and includes a central hub (140), an outer ring assembly (150) comprising magnetic elements and back-to-back curved webs (161, 162) radially interposed between the central hub (140) and the outer ring assembly (150).