Axial-Gap Stator Core Assembly With Interlocking Yoke Pieces
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Solution Overview
Problem
The assembly of axial-gap rotary electric machine cores into an annular shape is challenging due to radial displacement issues between core pieces with straight radial side surfaces, making it difficult to position and connect them effectively.
Innovation Solution
The core pieces are designed with protrusions on one side surface and corresponding recesses on the other, with an interval of 80% or less of the yoke portion's side surface length, allowing for easier alignment and assembly by fitting the protrusions into the recesses, reducing stress on the mold and preventing die breakage during formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If core pieces with straight radial side surfaces are used, then the manufacturing process is simple, but radial displacement occurs during assembly making it difficult to position and connect them effectively
Solution Approach 1:
The core is divided into multiple core pieces that are assembled together to form the complete annular core. Each core piece includes protrusions and recesses that enable precise positioning when assembled, solving the radial displacement issue while maintaining manufacturing simplicity through modular construction
Solution Approach 2:
Protrusions are provided on one side surface of each core piece while corresponding recesses are provided on the other side surface. This asymmetric design creates complementary features that fit together to prevent radial displacement during assembly, improving positioning accuracy without complicating the overall manufacturing process
2Ease of operation
If protrusions and recesses are provided on core pieces, then assembly is facilitated with reduced radial displacements, but the device complexity increases
Solution Approach 1:
The core is segmented into multiple pieces with standardized protrusion and recess features. This segmentation facilitates assembly by allowing pieces to be connected through simple fitting operations, and the standardized features prevent complexity from increasing proportionally with the number of core pieces
Solution Approach 2:
The core pieces have an annular configuration with curved side surfaces that connect to adjacent core pieces. This curvature is optimized to reduce radial displacement during assembly while maintaining manufacturability and avoiding excessive structural complexity
3Stress or pressure
If the interval between protrusions is large, then the mold stress is reduced, but the positioning accuracy during assembly deteriorates
Solution Approach 1:
The interval between protrusions is optimized to balance two competing requirements: it is sufficiently small to provide accurate positioning during assembly, yet sufficiently large to reduce stress concentration on the mold during the formation process. This parameter optimization resolves the contradiction between mold stress and positioning accuracy
Data Source
AI summary
A core for use in an axial-gap rotary electric machine is annular and includes a plurality of core pieces into which the core is divided in a circumferential direction. Each core piece includes a yoke portion and a tooth portion that is formed integrally with the yoke portion and that projects from the yoke portion in an axial direction. Each yoke portion includes a plurality of protrusions provided on one side surface connected to the yoke portion of an adjacent one of the core pieces, and a plurality of recesses provided on other side surface connected to the yoke portion of another adjacent one of the core pieces, the recesses corresponding to the protrusions. An interval between the protrusions is 80% or less of a length of the one side surface of the yoke portion, the length being a direct distance between inner and outer peripheries of the yoke portion.