Stator Core Stamping Layout for Torque Cogging and Scrap Reduction
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Solution Overview
Problem
The existing methods for manufacturing stator cores from electromagnetic steel sheets result in significant scrap material and increased costs due to magnetic anisotropy issues caused by the rolling direction of the sheets, especially when cores are not aligned in the rolling direction, and arranging them in multiple rows does not effectively reduce scrap without introducing additional structural complexities.
Innovation Solution
The method involves setting the positions of stamping out stator cores with an angular difference of 360 degrees÷(4×motor pole pair number between their rolling directions, ensuring that the orientation of the shortest segments among virtual segments linking opposite sides or diagonals is not orthogonal to the rolling direction, and stamping out at least two cores alongside in the width direction, allowing for parallel or aligned shortest segments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stator cores are stamped out sloping relative to the rolling direction to suppress torque cogging, then magnetic performance is improved, but scrap amount increases and manufacturing cost increases
Solution Approach 1:
The patent transitions from single-row stamping to multi-row stamping arrangement, utilizing the width direction of the electromagnetic steel sheet more effectively. By arranging stamping positions in multiple rows with specific angular relationships, the method achieves both torque cogging suppression and reduced scrap material.
Solution Approach 2:
The patent employs asymmetric angular positioning of stator cores in different rows relative to the rolling direction. The angular difference between adjacent rows is set to 360°÷(4×motor pole pair number), creating an asymmetric pattern that balances magnetic anisotropy effects while optimizing material utilization.
2Loss of substance
If stator cores are arranged in multiple rows to reduce scrap, then material utilization is improved, but magnetic anisotropy influence may increase
Solution Approach 1:
The patent applies different angular orientations to stator cores in different rows. Each row has a specific angular relationship with the rolling direction, creating local variations in magnetic properties that collectively balance the overall magnetic anisotropy influence while maximizing material utilization.
Solution Approach 2:
The asymmetric angular positioning strategy is applied to different rows, where the angular difference between adjacent rows is precisely controlled at 360°÷(4×motor pole pair number). This asymmetric arrangement ensures that magnetic anisotropy effects are distributed and balanced across the stator assembly.
3Loss of substance
If stator cores are aligned in the rolling direction to minimize scrap, then manufacturing cost is reduced, but torque cogging increases
Solution Approach 1:
The patent moves beyond simple alignment in the rolling direction by introducing multi-row arrangement with controlled angular offsets. This dimensional expansion in the angular domain allows simultaneous achievement of low scrap and low torque cogging.
Solution Approach 2:
By introducing asymmetric angular positioning in multiple rows rather than simple alignment, the patent eliminates the harmful torque cogging effect while maintaining high material utilization. The asymmetric pattern distributes magnetic flux more evenly.
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 effectively reduces scrap material and suppresses the influence of magnetic anisotropy, leading to lower manufacturing costs and improved manufacturability by optimizing the arrangement of stator cores to minimize waste and enhance the quality of the stator assembly.
Implementation Method 1
The electromagnetic steel sheet serving as the material for the stator core has magnetic anisotropy whereby the magnetic permeability differs between the rolling direction thereof and a direction orthogonal to the rolling direction
Data Source
AI summary
In a method for manufacturing a stator of the present invention, positions of stamping out the first stator core and the second stator core are respectively set so that an angular difference between respective rolling directions thereof becomes 360 degrees÷(4×motor pole pair number), when laminating the first stator core which is not circular stamped out from a first electromagnetic steel sheet, and the second stator core which is not circular stamped out from a second electromagnetic steel sheet. For the second stator core, orientation of a shortest segment among virtual segments linking opposite sides or diagonals which pass through a center thereof is not orthogonal to the rolling direction, and at least two are stamped out alongside in a width direction.