Laminated Iron Core Bridge Deformation Control
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Solution Overview
Problem
Existing methods for manufacturing laminated iron cores with punched holes, such as magnet-insert holes, face issues with deformation of bridge portions between holes and the outer peripheral edge, leading to reduced magnetic efficiency due to clearance between punches and bridge portions during the blanking process.
Innovation Solution
A method involving coining to form thinned bridge portions between punched holes and the outer peripheral edge of the iron core piece, using a projection portion on the outer-shape blanking punch to support the bridge portions during blanking, thereby preventing deformation and enhancing magnetic efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If thin-wall processing is performed from the upper surface side of the iron core piece to form bridge portions, then the bridge portions can be formed between punched holes and the outer peripheral edge, but clearances are produced between the punch and bridge portions during blanking, causing the bridge portions to deform outward in the radial direction
Solution Approach 1:
The bridge portions are formed by thin-wall processing before the blanking operation. This preliminary formation of bridge portions with reduced thickness allows them to be more flexible during subsequent blanking, enabling the punch to contact and support them effectively, thereby preventing outward deformation during the blanking process.
Solution Approach 2:
The thin-wall processing creates localized thinning of the bridge portions specifically at the regions between punched holes and the outer peripheral edge. This local quality change allows the bridge portions to have different mechanical properties compared to the rest of the iron core piece, making them more susceptible to punch contact and support during blanking, thus preventing deformation.
2Shape
If the bridge portions are formed to extend over the outer peripheral edge of the iron core piece, then they can connect punched holes to the outer edge, but deformation is transmitted to the magnet-insert holes as well, reducing magnetic efficiency
Solution Approach 1:
The bridge portions are formed in advance by thin-wall processing before blanking. This preliminary formation ensures that when blanking occurs, the punch can contact the bridge portions and prevent deformation from being transmitted to the magnet-insert holes, thereby maintaining magnetic efficiency while still achieving the desired connectivity.
Solution Approach 2:
The thin-wall processing changes the thickness parameter of the bridge portions, creating a gradient where the bridge portions are thinner than the main body of the iron core piece. This parameter change allows the bridge portions to deform preferentially during blanking, protecting the magnet-insert holes from deformation and preserving magnetic efficiency.
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 method effectively eliminates or reduces deformation of bridge portions, improving the magnetic efficiency of magnet-insert holes and maintaining the precision of the iron core pieces by ensuring proper contact between the punch and bridge portions, thus enhancing the overall performance of the laminated iron core.
Implementation Method 1
coining the thin sheet from above to form a thinned bridge portion on an outer peripheral portion of an iron core piece
Implementation Method 2
magnetic flux directed toward the front and back of the permanent magnets provides a magnetic path in the outer peripheral portions of the magnet-insert holes
Data Source
AI summary
In a method for manufacturing a laminated iron core from a thin sheet, the method includes coining the thin sheet from above to form a thinned bridge portion on an outer peripheral portion of an iron core piece, blanking the iron core piece downwardly from the thin sheet using a set of an outer-shape blanking punch and a die after forming the bridge portion, wherein the outer-shape blanking punch includes a projection portion fitted into the bridge portion when blanking, and laminating the iron core piece on another iron core piece to manufacture the laminated iron core.