Rotary Electric Machine Core With Expandable Segments
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Solution Overview
Problem
Conventional rotary electric machine armature cores face issues with reduced material yield, increased labor costs, and decreased productivity due to enlarged notches or split magnetic pole tooth portions, which affect driving torque and torque pulsation, and require larger pressing dies.
Innovation Solution
A core segment linked body with rotatable back yoke portions and magnetic pole tooth portions that can expand or contract, allowing for staggered punching of core segments, improving material yield and productivity without compromising machine characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If notches are enlarged to accommodate magnetic pole tooth portion tips for punching two staggered straight rows together, then productivity is improved, but driving torque is reduced and torque pulsation deteriorates
Solution Approach 1:
The core is divided into multiple core segments that are linked together circumferentially. Each core segment contains multiple magnetic pole tooth portions, and the segmentation allows for flexible arrangement patterns (staggered, straight, or mixed) when punching multiple rows together, improving productivity without compromising torque characteristics
Solution Approach 2:
The core segments are designed with rotatable linkages at their ends, allowing them to be dynamically arranged in different configurations during assembly. This dynamic arrangement capability enables optimal positioning for punching efficiency while maintaining proper magnetic pole tooth alignment for torque performance
2Loss of substance
If magnetic pole tooth portions are split and separated to implement punching two staggered straight rows together, then material yield is improved, but labor time for manufacturing increases and pressing die size increases
Solution Approach 1:
The core is segmented into modular units that can be punched in multiple rows simultaneously. The segmentation allows for efficient material utilization with reduced waste while maintaining complete magnetic pole tooth structures within each segment, eliminating the need for splitting and subsequent assembly operations
Solution Approach 2:
Multiple core segments are combined circumferentially to form the complete core structure. This merging approach allows for punching two or more staggered straight rows together in a single operation, improving material yield without increasing labor time or pressing die size, as the segments are designed to be assembled through simple linking
3Reliability
If widths of magnetic pole tooth portions are increased to improve machine characteristics, then performance is improved, but material yield decreases
Solution Approach 1:
The core segments are arranged in a circumferential dimension around the rotary electric machine, allowing for efficient space utilization. This dimensional arrangement enables increased magnetic pole tooth widths for improved performance while maintaining high material yield through optimized circumferential packing and reduced radial waste
Data Source
AI summary
In a core for a rotary electric machine, first end portions of back yoke portions are linked to second end portions of back yoke portions of adjacent core segments so as to be rotatable around pivot portions. Each of the core segments is configured by alternately laminating first core segment sheets and second core segment sheets. The pivot portions are constituted by interfitting protruding portions that are formed on the first core segment sheets. The core segments are displaceable relative to the adjacent core segments between a contracted position in which spacing between the magnetic pole tooth portions is contracted and an expanded position in which spacing between the magnetic pole tooth portions is expanded, when the core segment linked body is opened out rectilinearly.