Stator Lamination Sub-segment Arrangement for Grain Alignment
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Solution Overview
Problem
Existing methods for producing lamination stacks for electric machines do not efficiently utilize sheet metal and achieve optimal electromagnetic properties, leading to suboptimal efficiency and material waste.
Innovation Solution
The method involves arranging and stamping out sheet metal sub-segments in rows aligned with the rolling direction of the sheet metal strip, with radial edges transverse to the strip's longitudinal direction, and using a tongue-and-groove connection for assembly, ensuring uniform grain alignment and efficient material use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If ring-shaped sheet metal laminations are stamped out of a sheet metal strip, then a stator can be formed, but material utilization is poor and waste is generated
Solution Approach 1:
The ring-shaped sheet metal lamination is divided into multiple sub-segments (first sub-segments and second sub-segments) that can be arranged and stamped out in rows from the sheet metal strip. This segmentation allows for more efficient nesting and utilization of the strip material, reducing waste portions while maintaining the ability to assemble a complete stator ring.
2Loss of substance
If sub-segments are arranged in rows aligned with rolling direction, then material utilization improves, but achieving uniform grain alignment for optimal magnetic flux becomes challenging
Solution Approach 1:
The patent employs asymmetric arrangement of sub-segments in two different rows (first row and second row) with specific orientations relative to the rolling direction. The first sub-segments have radial edges at specific angles while second sub-segments are rotated by 180 degrees, creating an asymmetric pattern that optimizes both material utilization and grain alignment for magnetic flux consistency.
Solution Approach 2:
Different sub-segments are oriented at different angles relative to the rolling direction based on their position in the stator ring. This local variation in orientation ensures that each sub-segment's grain structure aligns optimally with the magnetic flux path in its specific location, while collectively achieving uniform electromagnetic properties across the entire stator.
3Loss of substance
If sub-segments are stamped out with radial edges transverse to strip longitudinal direction, then material waste is minimized, but manufacturing precision requirements increase
Solution Approach 1:
The sheet metal strip is pre-oriented with its rolling direction aligned with the desired radial direction of the stator ring before stamping. The sub-segments are designed with radial edges that are transverse to the strip longitudinal direction, and the stamping process is configured to cut along these predetermined lines, thereby minimizing waste while maintaining achievable manufacturing precision through proper tooling and process setup.
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 enhances the electromagnetic properties and efficiency of electric machines by minimizing material waste and ensuring consistent magnetic flux across the lamination stack, resulting in improved performance and economical production.
Implementation Method 1
When rolling a sheet metal strip the process results in a stretching of the metal grains in the sheet metal strip in the longitudinal direction of rolling or rather in the longitudinal direction of the strip
Implementation Method 2
In order to form a tongue-and-groove connection when assembling the sub-segments each sub-segment is stamped out with a groove on a first lateral edge and with a matching tongue on the opposite second lateral edge
Data Source
AI summary
The invention relates to a method for producing a lamination stack for a rotor and/or a stator of an electric machine, wherein the lamination stack is produced of a stack of disk- or ring-shaped sheet metal laminations which are assembled of sub-segments that each have a radial outer edge, a radial inner edge and two lateral edges, wherein the sub-segments are stamped out of a sheet metal strip having a strip longitudinal direction that corresponds to a rolling direction of the sheet metal strip. In accordance with the invention provision is made in that for the purpose of stamping-out of the sheet metal strip first sub-segments are arranged in a first row and second sub-segments are arranged in a second row and stamped out, wherein the first row and the second row run in the strip longitudinal direction of the sheet metal strip and lie next to each other, in that the first sub-segments in the first row are aligned identically with respect to each other, wherein the radial outer edge and/or the radial inner edge run transversely to the longitudinal direction of the strip, and in that the second sub-segments in the second row are arranged identically with respect to each other, with radial outer edges and/or radial inner edges running transversely to the longitudinal direction of the strip, but diametrically opposed to the first sub-segments in the first row on the sheet metal strip.