Stator Outer Casing Brim Segmentation for Core Roundness
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Solution Overview
Problem
The reduction in thickness of the outer casing of electric rotating machines to achieve compactness leads to a decrease in the roundness of the stator core due to reduced rigidity, compromising the machine's performance.
Innovation Solution
The introduction of brim portions at the axial ends of the outer casing, which project in a direction receding from the center axis, increases the rigidity and maintains the roundness of the stator core by providing a clamping margin during the shrink-fitting process, allowing for a more compact and high-output design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thickness of the outer casing is reduced to achieve compactness, then the size of the electric rotating machine is reduced, but the roundness of the stator core is lowered due to reduced rigidity
Solution Approach 1:
The outer casing is divided into a body portion and brim portions, where the brim portions are spaced apart in the circumferential direction. This segmentation creates localized rigid structures that maintain the roundness of the stator core while allowing the overall casing thickness to be reduced for compactness.
Solution Approach 2:
The brim portions project in the radial direction (receding from the center axis) rather than only in the axial direction. This dimensional change adds rigidity in the radial direction where it is most needed for maintaining roundness, while keeping the axial length compact.
2Volume of moving object
If the thickness of the outer casing is reduced, then the machine becomes more compact, but the rigidity of the outer casing decreases
Solution Approach 1:
The outer casing is segmented into a body portion and multiple brim portions spaced circumferentially. This segmentation creates localized rigid structures that provide necessary rigidity while allowing the overall casing to be thinner for compactness.
Solution Approach 2:
The brim portions are provided with greater thickness or structural reinforcement at specific locations where rigidity is most needed, while other portions of the casing can be thinner. This local quality approach maintains overall rigidity without increasing the entire casing thickness.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enhances the roundness and rigidity of the stator core, ensuring a compact and high-output electric rotating machine while preventing deformation and maintaining the structural integrity of the stator core.
Implementation Method 1
the outer casing whose inner diameter is slightly smaller than the outer diameter of the ring assembly of the split cores is set in place, and the ring assembly is fitted into the outer casing which is being heated so that its inner diameter expands
Implementation Method 2
After completion of the shrink-fitting, the ring assembly of the split cores and the outer casing are fixed firmly to each other by the stress due to difference between their diameters
Data Source
AI summary
The stator of an electric rotating machine includes a stator core constituted of a plurality of split cores joined to one another in a ring, a plurality of phase windings wound around the stator core, and an outer casing to an inner periphery of which an outer periphery of the stator core is fitted with clamping margin therebetween. The outer casing is provided with a brim including at least two brim portions at least at one of axial ends thereof. The brim portions are spaced from each other in a circumferential direction of the outer casing and project in a direction receding from a center axis of the outer casing.