Laminated Iron Core Welding Sequence Inversion
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Solution Overview
Problem
The welding process for laminated iron cores often results in cracks due to residual stress in the tensile direction, leading to deteriorated welding quality, particularly at the welded portions where the endmost iron core piece is joined.
Innovation Solution
The laminated iron core manufacturing method involves welding the endmost metal sheet last, ensuring the welding end is in contact with at least one endmost metal sheet, and performing multiple overlapping welds while shifting the position to distribute stress and prevent crack formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If welding is performed on the endmost iron core piece to prevent separation, then the structural integrity of the laminated iron core is improved, but residual stress in the tensile direction causes cracks in the welded portion
Solution Approach 1:
The patent inverts the conventional welding sequence by welding the endmost iron core piece last instead of first. This reversal allows the welded portion to be free from constraints by adjacent pieces during welding, preventing residual stress-induced cracks while maintaining welding strength.
Solution Approach 2:
The patent applies preliminary action by positioning and fixing the endmost iron core piece in its final position before welding. This preliminary positioning ensures that when welding occurs, the piece is already in the correct location, allowing the weld to be performed without constraint from neighboring pieces, thereby preventing crack formation.
2Stability of the object's composition
If the endmost iron core piece is welded to adjacent pieces, then separation of the endmost piece is prevented, but the welding process generates residual stress that deteriorates welding quality
Solution Approach 1:
The patent inverts the welding sequence to weld the endmost piece last, which prevents the welded portion from being constrained by adjacent pieces during welding. This inversion eliminates the generation of residual stress in the tensile direction, thereby preventing cracks and improving welding quality while maintaining lamination stability.
Solution Approach 2:
The patent performs preliminary positioning of the endmost iron core piece before welding. By pre-positioning the piece in its final location, the welding process can be performed without the piece being constrained by adjacent pieces, preventing residual stress accumulation and crack formation while ensuring stable lamination structure.
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 improves the welding quality by relaxing residual stress and increasing the welding strength of the laminated iron core, preventing cracks and enhancing the structural integrity of the welded portions.
Implementation Method 1
an endmost metal sheet located at an endmost position in a lamination direction and the metal sheet in contact with the endmost metal sheet are welded
Implementation Method 2
cracks may occur in a welded portion due to residual stress in a tensile direction generated when the welded portion contracts during cooling
Data Source
AI summary
A laminated iron core includes a laminated body including a plurality of laminated metal sheets. The laminated body includes a welded portion where an endmost metal sheet located at an endmost position in a lamination direction and the metal sheet in contact with the endmost metal sheet are welded. A welding end of the welded portion is in contact with at least one endmost metal sheet.