Wound Core Grain Orientation Control for Lower Iron Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for producing wound cores by bending steel sheets and laminating them result in inefficiencies due to iron core efficiency deterioration during the bending process, particularly due to differences in iron loss, which are not effectively minimized.
Innovation Solution
A wound core design is implemented where grain-oriented electrical steel sheets with specific chemical composition and crystal orientation control are used, with bent portions having a radius of curvature between 1 mm and 5 mm, and planar portions adjacent to bent portions satisfying specific formulae to optimize iron core efficiency by controlling grain boundary distribution and crystal orientation variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If steel sheets are bent with a small radius of curvature (3 mm or less) to form corner portions, then the processing strain is concentrated only in the bent portion and annealing can be omitted, but the iron core efficiency deteriorates due to increased iron loss
Solution Approach 1:
The patent optimizes the radius of curvature parameter of bent portions to be 5 mm or less (specifically 1-5 mm in preferred embodiments), which concentrates strain in small regions without excessive iron loss. Additionally, the patent controls grain boundary characteristics (Nt/Nx ratio, Nb/Na ratio, Nb/Nc ratio) and average grain boundary angle (φ3Dave) to minimize iron loss while maintaining the bending advantage
Solution Approach 2:
The patent creates different grain boundary characteristics in different regions: planar portions adjacent to bent portions have controlled grain boundary distributions (specific Nt/Nx, Nb/Na, Nb/Nc ratios) that reduce iron loss, while bent portions concentrate the necessary processing strain. This local differentiation allows simultaneous achievement of manufacturing simplicity and low iron loss
2Loss of energy
If the radius of curvature of bent portions is increased, then iron core efficiency improves, but the bending precision and shape maintenance capability deteriorate
Solution Approach 1:
The patent identifies an optimal parameter range for the radius of curvature (5 mm or less, preferably 1-5 mm) that balances shape maintenance capability with iron core efficiency. This precise parameter control ensures that the bent portions maintain their shape while minimizing iron loss through controlled strain concentration
3Reliability
If grain-oriented electrical steel sheets with high magnetic flux density are used, then the magnetic properties improve, but the iron loss during bending increases
Solution Approach 1:
The patent creates favorable grain boundary conditions specifically in planar portions adjacent to bent portions (controlled Nt/Nx, Nb/Na, Nb/Nc ratios and φ3Dave angle) to reduce iron loss in high-stress regions, while maintaining high magnetic flux density in the bulk material. This local optimization allows high-performance steel sheets to be used without excessive bending loss
Data Source
AI summary
This wound core is a wound core including a wound core main body obtained by stacking a plurality of polygonal annular grain-oriented electrical steel sheets in a side view, and the grain-oriented electrical steel sheet has planar portions and bent portions that are alternately continuous in a longitudinal direction, and in a planar portion in the vicinity of at least one bent portion, when the three-dimensional crystal orientation difference between two adjacent points in a series of points arranged at equal intervals in the extension direction of the bent portion is φ, a total number of measured data items of φ is Nx, the number of data items that satisfy φ≥1.0° is Nt, the number of data items that satisfy φ of 1.0° or more and less than 2.5° is Na, the number of data items that satisfy φ of 2.5° or more and less than 4.0° is Nb, and the number of data items that satisfy φ of 4.0° or more is Nc, the following formulae (1) to (4) are satisfied:0.10≤Nt/Nx≤0.80 (1)0.37≤Nb/Nt≤0.80 (2)1.07≤Nb/Na≤4.00 (3)Nb/Nc≥1.10 (4)