Stator Core Recess Structure for Stable Motor Case Press-Fit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing stator core assembly process results in unstable press-fit forces, positional deviations, and increased core loss due to stress concentration and burr surface resistance during press-fitting into a motor case, leading to potential deformation and noise generation.
Innovation Solution
A stator core design featuring recessed surface portions on the back yoke and pole teeth to distribute stress evenly, with match marks further recessed inward to prevent edge resistance and ensure accurate lamination and assembly, reducing the risk of deformation and core loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If match marks are punched in the back yoke for positioning electromagnetic steel sheets, then lamination positioning accuracy is improved, but edge resistance is generated at the boundary between the back yoke and match marks during press-fitting
Solution Approach 1:
The patent applies local quality by creating recessed surface portions at specific locations where the back yoke and pole teeth cross each other. These recessed portions are localized modifications that reduce edge resistance only at the critical crossing areas, while preserving the positioning function of match marks elsewhere. This selective modification allows the press-fit force to be applied more uniformly without compromising lamination positioning accuracy.
2Ease of manufacture
If the entire periphery of the back yoke becomes a press-fit surface, then assembly simplicity is improved, but stress concentration occurs at crossing parts between pole teeth and back yoke
Solution Approach 1:
The patent segments the back yoke periphery by introducing recessed surface portions at the crossing parts between pole teeth and back yoke. This segmentation divides the continuous press-fit surface into distinct regions: the recessed portions that reduce stress concentration and the remaining areas that maintain press-fit functionality. This allows stress to be distributed more evenly during assembly while preserving the overall simplicity of the assembly process.
3Reliability
If press-fit force is increased to ensure stable assembly, then assembly reliability is improved, but deformation and core loss increase in the stator core
Solution Approach 1:
The patent implements beforehand cushioning by pre-forming recessed surface portions at the crossing parts between pole teeth and back yoke before the press-fitting process. These recessed portions act as cushioning zones that absorb and distribute press-fit stress, preventing excessive localized pressure that would cause deformation. This allows sufficient press-fit force to be applied for reliable assembly without exceeding the deformation threshold of the electromagnetic steel sheets.
Data Source
AI summary
In the stator core, recessed surface portions uniformly recessed toward an inner side in a radial direction over a range wider than a width of each of pole teeth are respectively formed on an outer peripheral surface where an annular back yoke and each of the pole teeth provided to protrude on the inner side in the radial direction cross each other.