Ceramic Fiber Soft-Magnetic Motor Core for Low Loss and Strength

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Solution Overview

Problem

Conventional electric motors face limitations in mechanical strength and high-temperature performance due to the use of soft-magnetic materials, which are inadequate for applications with high mechanical stress and elevated temperatures.

Innovation Solution

The development of an electric motor with a stator and a moving component, where the moving component is made of an iron-based soft-magnetic structural material reinforced with ceramic fibers. This material includes crystallites of a ferromagnetic iron-based alloy with interlayer-free contact and ceramic fibers with a fiber content between 0.2% and 10% by volume, and an aspect ratio less than 0.1.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If SMC materials are used for soft-magnetic cores, then eddy current suppression and three-dimensional flux guidance are improved, but mechanical strength deteriorates

Engineering Contradiction:

Improveeddy current lossesVSAvoidmechanical strength

Core Design Contradiction:

Loss of energyVSStrength

Solution Approach 1:

The patent applies composite materials by combining ferromagnetic iron-based alloy crystallites with ceramic fibers to create a soft-magnetic structural material. This composite structure allows the material to simultaneously achieve low eddy current losses through the ferromagnetic properties and high mechanical strength through the ceramic fiber reinforcement, directly resolving the contradiction between energy loss suppression and mechanical strength.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the material parameters by controlling the fiber content between 0.2% and 10% by volume and the aspect ratio of fibers to be less than 0.1. These parameter optimizations enable the material to achieve both low electrical resistance for eddy current suppression and adequate mechanical strength for high-speed applications.

Inventive Principle:

Principle #35Parameter changes

2Strength

If conventional laminated stacks are used, then mechanical strength is improved, but three-dimensional flux guidance capability deteriorates

Engineering Contradiction:

Improvemechanical strengthVSAvoidthree-dimensional flux guidance

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

The composite material structure combines the mechanical strength advantages of laminated stacks with the three-dimensional flux guidance capabilities of SMC materials. The ceramic fiber-reinforced ferromagnetic alloy provides both structural integrity and isotropic magnetic properties, enabling the material to perform both functions simultaneously.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent achieves local quality optimization by creating a material with uniform distribution of crystallites and ceramic fibers throughout the structure. This homogeneous composite structure provides consistent mechanical strength in all directions while maintaining three-dimensional magnetic flux guidance capability, unlike conventional laminated stacks that are strong only in-plane.

Inventive Principle:

Principle #3Local quality

3Strength

If fiber content is increased to improve mechanical strength, then eddy current suppression deteriorates

Engineering Contradiction:

Improvemechanical strengthVSAvoidelectrical losses

Core Design Contradiction:

StrengthVSLoss of energy

Solution Approach 1:

The patent optimizes the fiber content parameter within the specific range of 0.2% to 10% by volume. This controlled parameter change ensures that sufficient ceramic fibers are present to provide mechanical strength reinforcement while maintaining low enough electrical resistance to achieve effective eddy current suppression. The aspect ratio parameter is also controlled to be less than 0.1 to minimize electrical pathway formation.

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 solution provides improved eddy current suppression, low electrical losses, and three-dimensional magnetic flux guidance, while significantly enhancing the mechanical strength of the magnetic core, enabling higher speeds of rotation or movement of the electric motor.

Implementation Method 1

improved eddy current suppression coupled with low electrical losses

Methodology Applied

Scientific EffectEddy current suppression: Eddy Currents

Implementation Method 2

crystallites (10) of a ferromagnetic iron-based alloy

Methodology Applied

Scientific EffectFerromagnetism: Ferromagnetism

Implementation Method 3

the possibility of three-dimensional magnetic flux guidance

Methodology Applied

Scientific EffectThree-dimensional flux guidance: Magnetic Field

Data Source

PatentUS12224623B2Electric motor

Publication Date: 2025.02.11 SIEMENS AG

AI summary

Various embodiments of the teachings herein include an electric motor. In some embodiments, the motor includes: a stator; and a moving component comprising an iron-based soft-magnetic structural material including crystallites of a ferromagnetic iron-based alloy separated by grain boundaries, wherein there is interlayer-free contact between the crystallites at grain boundaries. The structural material comprises ceramic fibers. A content of the ceramic fibers is between 0.2% and 10% by volume. An aspect ratio of the ceramic fibers is less than 0.1.