Electric Motor End Cover Cooling Structure for Leak-Safe Stators
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Solution Overview
Problem
Existing cooling systems for electric motors in compact vehicles face challenges in effectively cooling the stator windings, are limited to single coolant types, and compromise air and liquid cooling efficiency due to design constraints, leading to potential damage and reduced lifespan of stator windings.
Innovation Solution
A combined air and liquid cooling system for electric motors, utilizing a first end cover with a radially enclosed passage for coolant flow and protruded portions to enhance heat transfer, while preventing coolant leakage and allowing diverse coolant use, integrated with air-cooling fins for comprehensive cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If liquid cooling system is implemented, then cooling efficiency is improved, but stator windings may be damaged by coolant leakage
Solution Approach 1:
The end cover is segmented into multiple functional regions: a radially enclosed passage for coolant flow, protruded portions for heat transfer enhancement, and a base surface that acts as a protective barrier. This segmentation allows the cooling system to efficiently remove heat while the base surface prevents coolant from reaching and damaging the stator windings.
Solution Approach 2:
The base surface of the first end cover serves as an intermediary barrier between the coolant in the radially enclosed passage and the stator windings. It allows thermal energy to be transferred from the stator to the coolant while preventing direct contact between the coolant and the windings, thus protecting the windings from coolant damage.
2Temperature
If cooling system design is optimized, then cooling performance is improved, but design flexibility for coolant selection is reduced
Solution Approach 1:
The radially enclosed passage design with protruded portions creates a universal cooling structure that can effectively cool stators regardless of the coolant type used. The structure provides optimized coolant flow paths and heat transfer surfaces that work efficiently with various coolant properties, allowing designers to select from different coolant types (water, glycol mixtures, synthetic fluids) without compromising cooling performance.
3Temperature
If air cooling fins are added, then air cooling efficiency is improved, but device complexity increases
Solution Approach 1:
The cooling system merges air cooling and liquid cooling functionalities into a single integrated end cover structure. The air cooling fins are integrated with the radially enclosed passage and protruded portions, allowing both air and liquid cooling systems to work simultaneously from the same structural platform. This reduces overall device complexity compared to having separate air and liquid cooling systems.
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
The system effectively cools the stator and rotor, prevents damage to windings, and allows flexibility in coolant choice, optimizing both air and liquid cooling efficiencies.
Implementation Method 1
The base surface is in thermal connection with the stator
Implementation Method 2
The radially enclosed passage receives coolant from the outer wall
Implementation Method 3
protruded portions to enhance heat transfer
Implementation Method 4
air-cooling fins for comprehensive cooling
Data Source
AI summary
An electrical machine includes a stator; a rotor, the rotor being electrically coupled to the stator; a first end cover, the first end cover being in thermally conductive contact with the stator at a first side of the stator; and a lid attached to the first end cover from one side of the electrical machine for enclosing a coolant within the first end cover. The first end cover includes an outer wall, the outer wall having one or more ports for receiving the coolant; an end cover annular portion, the end cover annular portion and the outer wall being spaced at a first predetermined distance ‘a’; and a base portion, the outer wall and the end cover annular portion being projecting orthogonally to the base portion thereby forming a radially enclosed passage.