Rotor Core Block Overlap for Coolant Flow Continuity
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Solution Overview
Problem
In rotating electrical machines, skewing of core blocks can lead to coolant reservoirs in the cooling passage, causing imbalance and potential vibration due to incomplete coolant discharge.
Innovation Solution
The rotor yoke is designed with core blocks stacked at a predetermined angle, where the outer-diameter-side inner wall portions of adjacent core blocks overlap, forming an arcuate surface without steps, ensuring continuous coolant flow and preventing residue.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If core blocks are skewed to equalize distortion and magnetic characteristics, then manufacturing quality is improved, but coolant reservoirs form in the cooling passage causing incomplete discharge
Solution Approach 1:
The patent applies asymmetry by intentionally designing the outer-diameter-side inner wall portion of the opening to have a specific width (5mm or more) that creates an overlapping region when core blocks are skewed. This asymmetric design ensures that the coolant flow paths align properly despite the skewing angle, preventing reservoir formation while maintaining the manufacturing quality benefits of skewed core blocks.
Solution Approach 2:
The patent changes the geometric parameter of the opening's outer-diameter-side inner wall portion by specifying a minimum width (5mm or more). This parameter change ensures that when core blocks are skewed by a predetermined angle, the opening portions overlap sufficiently to maintain continuous coolant flow without creating reservoirs, thus resolving the contradiction between skewing benefits and coolant discharge reliability.
2Temperature
If coolant remains in the cooling passage due to reservoir formation, then rotor imbalance occurs, but increasing cooling passage volume would improve cooling efficiency
Solution Approach 1:
The asymmetric design of the outer-diameter-side inner wall portion with sufficient width (5mm or more) creates an overlapping region that eliminates dead zones where coolant could accumulate. This ensures complete coolant discharge while maintaining adequate cooling passage volume for effective heat dissipation, preventing rotor imbalance without sacrificing cooling efficiency.
Solution Approach 2:
The patent converts the potential harm of skewed core blocks (which could create coolant reservoirs) into a benefit by designing the opening width such that the skewing actually improves coolant flow alignment. The overlapping openings created by skewing ensure continuous flow paths, transforming what could be a harmful effect into a beneficial flow pattern that prevents imbalance while maintaining cooling efficiency.
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 design prevents coolant imbalance and subsequent vibration by ensuring complete coolant discharge and circulation, maintaining rotor stability during operation.
Implementation Method 1
the coolant flow paths of the adjacent first core block and second core block communicate in the axial direction via an arcuate surface having no step or coolant reservoir
Data Source
AI summary
A rotor of a rotating electrical machine includes: a magnet; and a rotor yoke including at least a first core block and a second core block formed by stacking steel plates, each of the steel plates includes an opening portion serving as a coolant flow path, the opening portion positioned on an outermost diameter side includes an outer-diameter-side inner wall portion with a predetermined width in a circumferential direction and located on an imaginary circle centered on an axis of the rotor, the second core block is arranged adjacent to the first core block while the second core block is rotated by a predetermined angle with respect to the first core block, and the predetermined width is a length at which the outer-diameter-side inner wall portions of the opening portions of the first core block and the second core block overlap each other when seen from the axial direction.