Rotary Electric Machine Core Punch Strength via Extended Stator Holes
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Solution Overview
Problem
The conventional manufacturing method for rotary electric machine cores faces challenges in ensuring the strength of the punch for forming holes radially outward of the bridge portion, particularly when performing composite molding of rotor and stator plate members from the same electric steel plate, as the through holes are often formed in regions where the stator core is located, leading to difficulties in punch strength and eccentric load resistance.
Innovation Solution
The method involves forming stator side hole portions with a larger width than the air gap between the rotor and stator cores, allowing for increased punch strength and enabling composite molding of rotor and stator plate members with bridge portions on the outer periphery by blanking the electric steel plate, ensuring the punch's strength against eccentric loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the through hole is formed only at the position corresponding to the air gap, then the stator core formation is enabled, but the punch strength is insufficient due to the small width
Solution Approach 1:
The through hole is extended in the circumferential direction beyond the air gap region, utilizing the wider stator core region to increase punch width. This dimensional extension allows the punch to be supported by a broader area, resolving the strength insufficiency while maintaining the ability to form the stator core.
Solution Approach 2:
The bridge portion serves as an intermediary structure that connects the rotor core region with the stator core region. By positioning the through hole to pass through the bridge portion and extend into the stator core region, the punch gains additional support area while still enabling stator core formation.
2Ease of manufacture
If the through hole is formed in the region outward of the rotor core, then the bridge portion is formed, but the composite molding of rotor and stator plate members becomes difficult
Solution Approach 1:
The through hole formation process merges the bridge portion formation with the stator core region utilization. By extending the through hole into the stator core region, the punch gains support area while the same structure enables both bridge portion formation and stator core formation, maintaining composite molding capability.
Solution Approach 2:
The through hole is positioned to extend in the radial direction through the bridge portion and into the stator core region. This spatial arrangement allows the hole to serve dual purposes: forming the bridge portion on the rotor side and providing punch support on the stator side, thus maintaining composite molding versatility.
3Manufacturing precision
If the punch width is reduced to match the air gap width, then the through hole positioning is improved, but the punch strength against eccentric load is insufficient
Solution Approach 1:
The through hole is extended in the circumferential direction beyond the air gap boundaries, utilizing the wider stator core region. This extension provides increased punch width and cross-sectional area for resisting eccentric loads, while the hole remains positioned to accurately define the bridge portion location.
Solution Approach 2:
The bridge portion acts as an intermediary that transmits the positioning function from the through hole to the rotor core, while the extended through hole in the stator core region provides the necessary structural support for punch strength against eccentric loads.
Data Source
AI summary
A manufacturing method of a core for a rotary electric machine including forming a bridge portion, forming a stator side hole portion in at least a first portion of a portion of an electric steel plate in which a slot portion is formed. Then forming a rotor side hole portion in at least a part of a portion of the electric steel plate in which a hole portion is formed; and forming a rotor plate member and a stator plate member by blanking the electric steel plate.