Rectangular Wound Core Structure for Low-Noise Tight Bending
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Solution Overview
Problem
Existing methods for producing wound cores with small bending radii result in noise issues due to the combination of iron core shape and steel sheet properties, which are not effectively minimized despite similar crystal orientation and magnetostriction control.
Innovation Solution
A wound core design featuring grain-oriented electrical steel sheets with specific chemical composition, bent angles, and interlaminar friction coefficients, where the sheets are laminated with a 90° angle between planar and corner portions, and a radius of curvature between 1 mm to 5 mm, to reduce noise generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If steel sheets are bent in advance to form small bending areas with radius of curvature of 3 mm or less, then the conventional large-scale pressing process is eliminated and strain is concentrated at corner portions, but noise is generated due to the combination of iron core shape and steel sheet properties
Solution Approach 1:
The patent changes the radius of curvature parameter from the conventional 3 mm or less to 5 mm or more, which fundamentally alters the bending characteristics and strain distribution. This parameter change eliminates the noise issue while maintaining the manufacturing advantages of the pre-bending method
Solution Approach 2:
The patent applies preliminary bending with a specific radius of curvature (5 mm or more) to counteract the noise-generating effect. By pre-setting the curvature within this specific range, the steel sheets are prepared in advance to prevent noise generation during subsequent lamination and operation
2Manufacturing precision
If the radius of curvature is reduced to 3 mm or less, then the bending area becomes smaller and strain is concentrated at corner portions, but this combination of small radius and corner geometry generates noise
Solution Approach 1:
The patent identifies the radius of curvature as a critical parameter and changes it from the conventional small value (3 mm or less) to a larger value (5 mm or more). This parameter change maintains shape precision while eliminating the noise-generating geometric combination
3Productivity
If steel sheets with small bending radius are laminated to form wound core, then the iron core maintains precise shape without annealing, but noise is generated due to interlaminar friction and magnetostriction
Solution Approach 1:
The patent changes the radius of curvature parameter to 5 mm or more, which modifies the strain distribution and interlaminar interaction characteristics. This parameter change reduces noise generation while maintaining the high productivity advantages of the annealing-free process
Solution Approach 2:
The patent creates an optimized version of the pre-bending method by copying the essential features (pre-bending, small bending area) while modifying the critical parameter (radius of curvature to 5 mm or more) to eliminate noise, thus improving upon the conventional approach
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 proposed solution effectively minimizes noise in wound cores by optimizing the interlaminar friction coefficients and magnetostriction distribution, leading to improved magnetic efficiency and reduced vibration energy.
Implementation Method 1
small magneto-striction, which causes vibration and noise
Implementation Method 2
interlaminar friction coefficients which are dynamic friction coefficients of the laminated grain-oriented electrical steel sheets
Data Source
AI summary
Provided is a wound core including: a substantially rectangular wound core main body in a side view, in which the wound core main body includes a portion in which grain-oriented electrical steel sheets in which planar portions and corner portions are alternately continuous in a longitudinal direction and an angle formed by two planar portions adjacent to each other with each of the corner portions therebetween is 90° are stacked in a sheet thickness direction and has a substantially rectangular laminated structure in a side view, each of the corner portions has two or more bent portions having a curved shape in a side view of the grain-oriented electrical steel sheets 1, the sum of bent angles of the bent portions present in one corner portion is 90°, each bent portion in a side view has an inner side radius of curvature r of 1 mm to 5 mm, and interlaminar friction coefficients which are dynamic friction coefficients of the laminated grain-oriented electrical steel sheets in at least some of the planar portions are 0.20 or more.