Stator Core Crimping Layout to Reduce Motor Iron Loss
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Solution Overview
Problem
Concentrated compressive stress in the stator core during the fixation of the casing and stator core leads to increased iron loss in rotating electric machines.
Innovation Solution
The crimping portions are arranged with long sides along the radial direction and short sides along the circumferential direction, and radial fixing portions are positioned to counteract the compressive stress with tensile stress, reducing stress concentration and iron loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the casing and stator core are fixed by applying compressive stress radially inward (arc welding method), then the fixation strength is improved, but compressive stress concentrates on the fixation portions causing iron loss to increase
Solution Approach 1:
The stator core is divided into multiple segments along the circumferential direction, with crimping portions and radial fixing portions arranged at different angular positions. This segmentation allows the stress distribution to be optimized, preventing stress concentration at any single location while maintaining strong fixation between the casing and stator core.
Solution Approach 2:
Different fixing methods are applied to different local regions of the stator core. Crimping portions are positioned at specific angular locations to provide localized stress relief, while radial fixing portions are strategically placed to maintain overall fixation strength. This local differentiation optimizes both fixation strength and stress distribution to reduce iron loss.
2Stability of the object's composition
If crimping portions are arranged to fix electrical steel sheets, then the stacking integrity is improved, but compressive stress in the circumferential direction increases
Solution Approach 1:
The crimping portions are designed with asymmetric positioning relative to the radial fixing portions along the circumferential direction. This asymmetric arrangement ensures that the compressive stress generated by crimping is counterbalanced by the tensile stress from radially inward fixation, preventing excessive circumferential compressive stress while maintaining stacking integrity.
Solution Approach 2:
The radial fixing portions provide a counteracting tensile stress that balances the compressive stress generated by the crimping portions. This stress counterbalance prevents excessive compressive stress in the circumferential direction while maintaining the stacking integrity of the electrical steel sheets.
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 arrangement effectively reduces compressive stress in the circumferential direction, minimizing iron loss and enhancing the efficiency of the electric motor.
Implementation Method 1
radial fixing portions (60) each arranged within an area of a first angle between two lines connecting an axial center of the stator core (32) and adjacent two of the crimping portions (50) in the circumferential direction and fixing the casing (11) and the stator core (32) using a method of applying compressive stress to the stator core (32) radially inward from an outside
Implementation Method 2
compressive stress in the circumferential direction is generated on both sides of the crimping portion (50) in the circumferential direction
Implementation Method 3
compressive stress by the crimping portions (50) is reduced by tensile stress in the circumferential direction by the radial fixing portions (60)
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A rotating electric machine includes a casing (11), a stator core (32), and radial fixing portions (60) fixing the casing (11) and the stator core (32) to each other using a method of applying point-like compressive stress to the stator core (32) radially inward from an outside. The radial fixing portions (60) are each arranged within the area of a first angle between two lines connecting the axial center of the stator core (32) and adjacent two of crimping portions (50) in a circumferential direction. The crimping portions (50) are each formed in a rectangular shape such that the long sides extend along the radial direction of the stator core (32) and the short sides extend along the circumferential direction of the stator core (32) when the stator core (32) is viewed in an axial direction.