Laminated Core Manufacturing Method for Rotary Electric Machines
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Solution Overview
Problem
The existing laminated core manufacturing methods face issues with shape accuracy and magnetic strain, leading to decreased efficiency and increased torque pulsations in rotary electric machines, and the durability of punches used for forming clearances is compromised due to discontinuous punching, making mass production challenging.
Innovation Solution
A method involving the sequential punching of specific regions on core pieces to facilitate linear arrangement and die-cut caulking, allowing for enhanced productivity and material yield by reducing processing-induced strain, and using a simpler punch design to improve durability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If lancing is used to form fit-abutting portions of adjacent core pieces, then the core pieces can be connected, but strain occurs in the bending supporting point region causing deterioration of shape accuracy and magnetic strain
Solution Approach 1:
The invention extracts and eliminates the lancing process from the manufacturing method. Instead of using lancing to form fit-abutting portions, the patent uses a punching process that directly forms the portions without creating strain in the bending supporting point region, thereby removing the harmful effect while maintaining the connection function.
2Productivity
If a single-step punch is designed to punch out clearances and peripheral portions together, then productivity is improved, but stress concentrates in the connected portion causing deteriorated punch durability
Solution Approach 1:
The invention segments the punching operation into multiple steps: first punching out the clearance portions, then punching out the peripheral portions. This segmentation distributes the stress throughout the process rather than concentrating it in a single step, thereby maintaining high productivity while significantly improving punch durability by avoiding stress concentration in connected portions.
3Loss of substance
If core pieces are arranged linearly for pressing to enhance yield ratio, then material utilization is improved, but processing-induced strain occurs affecting efficiency and torque pulsations
Solution Approach 1:
The invention replaces the traditional lancing-based mechanical system with a punching-based system. The punching process, when applied to linearly arranged core pieces, creates minimal processing-induced strain compared to lancing, thereby maintaining the high material yield ratio advantage of linear arrangement while preserving shape accuracy and reducing torque pulsations.
4Reliability
If punching is performed in multiple steps to improve punch durability, then manufacturing reliability is improved, but processing time increases reducing productivity
Solution Approach 1:
The invention applies preliminary action by first punching out the clearance portions, then subsequently punching out the peripheral portions. This staged approach allows each punch to be optimized for its specific task, improving overall punch durability while maintaining efficient processing. The preliminary clearance punching creates favorable conditions for the subsequent peripheral punching, reducing overall processing time compared to a single-step approach.
Data Source
AI summary
A laminated core manufacturing method is linearly arranging and punching out a plurality of separate core pieces formed of a back yoke portion and a magnetic-pole teeth portion protruding from the back yoke portion and die-cut caulking. The manufacturing method includes: a first step of punching out a first region located on an opposite side to the magnetic-pole teeth portion between adjacent ends of the back yoke portions of the core pieces; a second step of punching out a second region located on a side of the magnetic-pole teeth portion between the adjacent ends of the back yoke portions of the core pieces; a third step of punching out a region that brings the first region punched out in the first step and the second region punched out in the second step into communication; and a fourth step of forming the magnetic-pole teeth portion by punching.