Rotary Electric Machine Stator Core Positioning
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Solution Overview
Problem
Conventional rotary electric machines face issues with positioning accuracy and motor characteristics due to low stiffness and manufacturing accuracy, leading to noise generation and torque reduction, particularly when the stator core is press-fitted or burn-fitted to the ring component.
Innovation Solution
A rotary electric machine design featuring a ring component with a cylinder and flange, where the fitting outer surface of the cylinder is fitted to a fitting inner surface of the housing with a lower clearance, enhancing stiffness and manufacturing accuracy, and allowing precise positioning of the stator core in the diameter direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the other end portion of the cylinder is used for positioning with lower clearance to the housing, then positioning accuracy in radial direction is improved, but stiffness of that portion is low causing deformation during press-fitting
Solution Approach 1:
The patent divides the positioning function into two separate locations: the flange portion for primary positioning and radial positioning, and the other end portion for axial positioning only. This segmentation allows each portion to have optimized clearance values suitable for its specific function, with the flange having higher stiffness for radial positioning and the other end having lower clearance for axial positioning without requiring high radial stiffness.
Solution Approach 2:
The patent applies different clearance values to different portions of the cylinder based on their specific functions. The flange portion has one clearance value optimized for radial positioning and stiffness, while the other end portion has a different (lower) clearance value optimized for axial positioning. This local differentiation resolves the contradiction by matching clearance characteristics to functional requirements at each location.
2Manufacturing precision
If the ring component is manufactured with high precision, then positioning accuracy is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The patent segments the positioning requirements into two independent locations (flange and other end portion), allowing each to be manufactured and assembled separately with appropriate tolerances. This reduces overall manufacturing complexity compared to requiring the entire cylinder to have uniformly high precision, while still achieving accurate positioning through the combined effect of both segmented positioning locations.
3Strength
If the stator core is press-fitted to the ring component, then connection strength is improved, but deformation of the ring component occurs due to low stiffness
Solution Approach 1:
The patent segments the support function by introducing the flange as a separate structural element that provides high-stiffness support during the press-fitting process. The flange acts as a rigid backing that prevents deformation of the ring component while the stator core is being press-fitted, while the other end portion with lower clearance provides axial positioning without requiring high radial stiffness.
Data Source
AI summary
In the rotary electric machine, a cylinder 04a of a ring component 04 is formed in such a way that a fitting outer surface 04c1 of the cylinder 04a of the ring component 04 is fitted to a fitting inner surface 02a of a first housing 02; a clearance value between the fitting outer surface of the cylinder and a fitting inner surface of the first housing is lower than a clearance value between an outer surface, in which the fitting outer surface is excepted, of the cylinder and an inner surface, in which the fitting inner surface is excepted, of the first housing; and a position in a diameter direction of a stator core 3 facing to the first housing is set by above-described fitting process.