Segmented Sealed Stator End Ring for Airgap-Safe Oil Cooling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for sealing the inner diameter of an electric machine stator are costly and often compromise the performance of the electric machine, either by shrinking the mechanical airgap or allowing magnetic flux leakage.
Innovation Solution
A sealed stator design that includes a stator core with windings and end rings with pocket compartments and radial ribs, allowing for effective sealing without adverse effects on performance, and utilizing a method of applying filler material to ensure a secure seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional sealing methods are used to seal the stator inner diameter, then sealing effectiveness is improved, but manufacturing cost increases
Solution Approach 1:
The end ring is divided into multiple segments arranged circumferentially around the end ring, with each segment comprising a pocket compartment defined between two radial ribs. This segmentation allows the sealing function to be distributed across multiple simple components rather than requiring a single complex sealing structure, reducing manufacturing cost while maintaining sealing effectiveness.
Solution Approach 2:
The patent introduces an intermediary sealing structure consisting of the end ring with pocket compartments and radial ribs that acts as a mediator between the stator core and the cooling oil. This intermediary structure prevents oil from entering the airgap while allowing cooling oil to contact the full length of the coil, achieving effective sealing without the need for expensive traditional sealing methods.
2Reliability
If closed slot stator lamination stack is used for sealing, then sealing is achieved, but magnetic flux leakage increases affecting performance
Solution Approach 1:
Instead of using a closed slot stator lamination stack that creates continuous magnetic flux leakage paths, the patent segments the end ring into multiple sections with radial ribs. This segmentation allows the sealing function to be achieved without creating continuous magnetic flux leakage paths across the entire stator, thus preventing magnetic flux leakage while maintaining sealing effectiveness.
Solution Approach 2:
The patent applies sealing functionality locally at the end ring with pocket compartments and radial ribs rather than requiring a global closed slot stator lamination stack. This localized sealing approach achieves the necessary sealing effect at the end turns without compromising the magnetic properties of the entire stator core, preventing magnetic flux leakage while maintaining local sealing effectiveness.
3Reliability
If traditional sealing devices are used, then sealing is improved, but mechanical airgap shrinks resulting in performance losses
Solution Approach 1:
The end ring is segmented into multiple sections with radial ribs creating pocket compartments, which provides sealing functionality without requiring a single large sealing structure that would encroach on the mechanical airgap. This segmented approach achieves effective sealing while maintaining the necessary mechanical airgap dimensions for optimal performance.
Solution Approach 2:
Instead of using axial sealing structures that would reduce the radial mechanical airgap, the patent implements sealing in the circumferential dimension through the end ring with radial ribs and pocket compartments. This dimensional shift allows sealing to be achieved without shrinking the mechanical airgap, maintaining performance while achieving the sealing objective.
Data Source
AI summary
A sealed stator for an electric machine is disclosed herein. In at least one embodiment, the sealed stator includes a stator core, stator windings positioned on the stator core, and an end ring coupled to the stator core. The stator core includes a plurality of slots. The windings include a plurality of interconnected conductors extending through the plurality of slots in the stator core. The end ring includes a plurality of segments arranged circumferentially around the end ring, each of the plurality of segments comprising a pocket compartment defined between two radial ribs. Each pocket compartment includes a radially outward pocket floor and a radially inward opening through the end ring. The plurality of interconnected conductors further extend through the openings in the end ring.