Rotor End Discs Balancing Composite Materials

Solution Overview

Problem

Large rotary electric machine rotors face challenges in balancing at high speeds while maintaining mechanical integrity and efficiency, as non-magnetic end discs used for vibration reduction lead to plastic deformation and parasitic currents, and magnetic end discs increase manufacturing and processing costs.

Innovation Solution

The rotor design incorporates end discs composed of two distinct metal components: a ferromagnetic inner component for mechanical strength and a non-magnetic outer component with balancing holes, allowing for dynamic balancing and minimizing parasitic currents, with a forced shape fitting to maintain structural integrity without significant power losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If non-magnetic metal material (stainless steel) is used for end discs, then parasitic currents are prevented and power losses are reduced, but mechanical strength is insufficient and plastic deformation occurs under rotational stress

Engineering Contradiction:

Improvepower lossesVSAvoidmechanical strength

Core Design Contradiction:

Loss of energyVSStrength

Solution Approach 1:

The end disc is divided into two separate components: an inner ferromagnetic component (13) and an outer non-magnetic component (14). The inner component provides the necessary mechanical strength to withstand rotational stresses, while the outer component prevents parasitic currents. This segmentation allows each material to fulfill its optimal function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The end disc uses a composite structure combining ferromagnetic metal material and non-magnetic metal material. This composite approach leverages the high mechanical strength of ferromagnetic materials and the parasitic current resistance of non-magnetic materials, achieving both requirements simultaneously through material composition rather than relying on a single material with compromised properties.

Inventive Principle:

Principle #40Composite materials

2Strength

If magnetic metal material is used for end discs, then mechanical strength and resistance to plastic deformation are improved, but parasitic currents increase and power losses worsen

Engineering Contradiction:

Improvemechanical strengthVSAvoidpower losses

Core Design Contradiction:

StrengthVSLoss of energy

Solution Approach 1:

The end disc is divided into two separate components: an inner ferromagnetic component (13) and an outer non-magnetic component (14). The inner component provides the necessary mechanical strength to withstand rotational stresses, while the outer component prevents parasitic currents. This segmentation allows each material to fulfill its optimal function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The end disc uses a composite structure combining ferromagnetic metal material and non-magnetic metal material. This composite approach leverages the high mechanical strength of ferromagnetic materials and the parasitic current resistance of non-magnetic materials, achieving both requirements simultaneously through material composition rather than relying on a single material with compromised properties.

Inventive Principle:

Principle #40Composite materials

3Loss of energy

If special non-magnetic metal material or non-metal material is used for end discs, then mechanical strength and parasitic current resistance are improved, but manufacturing costs and processing costs increase significantly

Engineering Contradiction:

Improveparasitic current resistanceVSAvoidmanufacturing costs

Core Design Contradiction:

Loss of energyVSEase of manufacture

Solution Approach 1:

Instead of using expensive special materials, the invention changes the structural parameter by creating a two-component end disc assembly. This allows the use of conventional, cost-effective ferromagnetic and non-magnetic metal materials that can be manufactured using standard industrial processes, significantly reducing both material and processing costs compared to specialized materials.

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

This design effectively balances the rotor at high speeds, resists mechanical stresses without plastic deformation, and reduces manufacturing costs by using conventional materials and production methods, ensuring efficient operation and long lifespan.

Implementation Method 1

a ferromagnetic inner component for mechanical strength

Methodology Applied

Scientific EffectFerromagnetism: Ferromagnetism

Implementation Method 2

a non-magnetic outer component with balancing holes, allowing for dynamic balancing and minimizing parasitic currents

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS10897179B2Rotor for a rotary electric machine

Publication Date: 2021.01.19 MARELLI EURO SPA

AI summary

A rotor for a rotary electric machine; the rotor has: a shaft, which is mounted so as to rotate around a rotation axis; a magnetic core, which is arranged around the shaft and consists of a plurality of lamination sheets stacked together; and a pair of end discs, which are arranged around the shaft at the two opposite ends of the magnetic core and are designed to keep the lamination sheets of the magnetic core stacked together; wherein the end discs are designed to have balancing holes, which dynamically balance the rotor around the rotation axis. Each end disc consists of an inner component with an annular shape, which is arranged around the shaft and is made of a first metal material, and of an outer component with an annular shape, which is arranged around the inner component and is made of a second metal material, which is different from the first metal material and is non-magnetic.