Soft-Magnetic Core Production Using Asymmetric Texture Orientation
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Solution Overview
Problem
Existing methods for producing soft-magnetic cores for generators face challenges such as anisotropic dimensional changes and imbalances in rotating core structures due to final annealing, which are intensified in large-volume applications, leading to undesirable anisotropies in magnetic and mechanical properties.
Innovation Solution
A method involving the preparation of CoFe or CoFeV alloy sheets with a cold-rolled texture, followed by magnetic forming and stacking with different texture directions, and subsequent structuring using erosion processes like wire erosion or laser beam cutting, with an electrically insulating coating applied to prevent thermal distortion and ensure rotational symmetry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cold-rolled sheets are stacked uniformly in the rolling direction to enhance magnetic effect, then magnetic properties in the GOSS texture direction are improved, but anisotropic dimensional changes and imbalances occur in rotating core structures
Solution Approach 1:
The patent applies asymmetry by deliberately orienting sheets with different texture directions (e.g., 0°, 45°, 90°) relative to the rolling direction, rather than uniform orientation. This asymmetric arrangement compensates for anisotropic dimensional changes during final annealing, preventing imbalances in rotating core structures while maintaining rotational symmetry of magnetic and mechanical properties.
Solution Approach 2:
The patent implements local quality by assigning different texture orientations to different sheets within the stack. Each sheet's orientation is locally optimized to counterbalance anisotropic effects, creating a heterogeneous structure that achieves overall dimensional stability and rotational symmetry in the final core.
2Reliability
If final annealing is performed after stacking to achieve optimal magnetic properties, then magnetic performance is improved, but anisotropic rearrangement causes dimensional changes and phase formations
Solution Approach 1:
The patent applies preliminary action by pre-orienting sheets with different texture directions before stacking and final annealing. This preliminary arrangement ensures that when anisotropic rearrangement occurs during final annealing, the dimensional changes are compensated, preventing phase formations and maintaining dimensional precision while achieving optimal magnetic properties.
3Productivity
If cold rolling is used to produce sheets, then manufacturing efficiency is improved, but crystalline texture forms causing anisotropies in magnetic and mechanical properties
Solution Approach 1:
The patent applies parameter changes by systematically varying the texture orientation parameter of individual sheets (e.g., 0°, 45°, 90°) while maintaining cold rolling for manufacturing efficiency. This parameter variation eliminates crystalline texture-induced anisotropies, achieving property uniformity and rotational symmetry without sacrificing productivity.
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 approach ensures dimensional stability and rotational symmetry of magnetic and mechanical properties, reducing anisotropic changes and achieving high saturation induction and mechanical strength suitable for high-speed applications.
Implementation Method 1
preparing a plurality of magnetically formed sheets of a CoFe alloy or a CoFeV alloy having a texture by means of a final anneal
Implementation Method 2
structuring the laminated core of magnetically formed laminations to form a soft-magnetic core, the structuring of the laminated core to form a soft-magnetic core by means of an erosion process, preferably by means of a wire erosion process
Implementation Method 3
by means of laser beam cutting or by means of water-jet-guided laser beam cutting
Data Source
AI summary
The invention relates to a method for production of a soft-magnetic core for generators and a generator comprising such a core. A number of magnetically-formed or magnetically-formable sheets of a CoFeV alloy with a texture are produced for the production of a core. The number of sheets are subsequently stacked to give a laminated core and the magnetically-formed laminated core eroded to give a soft-magnetic core. Such a core is suitable for a generator with a stator and rotor for a high-speed aircraft turbine, wherein the sheets on the laminated bundle are aligned with relation to each other in differing texture directions.