Electric Motor Stator Cooling via Integrated Coolant Annulus
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Solution Overview
Problem
Heat buildup in electric motors, particularly in hybrid electric motors with clutches, reduces operational performance and lifespan, necessitating effective cooling systems.
Innovation Solution
An electric machine design featuring a stator housing with a coolant annulus and spray passages that direct coolant onto the stator's end turns, combined with a coolant seal and distributor system to maintain coolant circulation and reduce heat, along with alignment features for precise stator positioning and a coolant reservoir for efficient fluid management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If coolant is passed through the electric motor to reduce heat buildup, then temperature is reduced, but device complexity increases due to the need for coolant annulus, spray passages, seals, and distributors
Solution Approach 1:
The patent combines multiple cooling functions into a single integrated coolant annulus system that circulates coolant around the stator assembly. The seal and distributor component integrates both sealing and coolant distribution functions, reducing the number of separate parts needed while achieving effective cooling of the stator windings.
Solution Approach 2:
The coolant acts as an intermediary substance that transfers heat from the stator windings to the surrounding environment. The coolant annulus serves as an intermediary structure that facilitates this heat transfer by providing a controlled pathway for coolant flow around the stator assembly.
2Reliability
If multiple coolant spray nozzles are added to improve coolant distribution, then cooling effectiveness is enhanced, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The coolant seal and distributor component performs multiple functions simultaneously: it seals the coolant within the annulus, distributes coolant through integrated spray nozzles, and positions the stator assembly. This multi-functionality reduces the total number of components needed while maintaining effective cooling coverage.
Solution Approach 2:
The spray nozzles are strategically positioned at specific locations where coolant is most needed, such as targeting the end turns and radial surfaces of the stator windings. This localized approach ensures effective cooling at critical heat generation points without requiring uniform spray coverage throughout the entire motor.
3Manufacturing precision
If alignment features and members are added to ensure precise stator positioning, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The alignment features are integrated directly into the stator housing structure, eliminating the need for separate alignment components. The housing itself provides the positioning function through built-in features that interface with corresponding features on the stator assembly.
Solution Approach 2:
The stator assembly includes self-aligning features such as protrusions that fit into corresponding recesses in the housing, allowing the components to automatically position themselves during assembly without requiring additional alignment tools or procedures.
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 solution effectively reduces stator operating temperatures, enhances the reliability and service life of electric machines by ensuring efficient coolant distribution and heat exchange, addressing the heat-related performance and lifespan issues.
Implementation Method 1
coolant is typically passed through the electric motor... coolant spray passages arranged to direct a spray of coolant at one of the first end turn and the second end turn
Implementation Method 2
coolant may take the form of a fluid such as air, water or oil... direct a spray of coolant onto the other of the first end turn and the second end turn
Data Source
AI summary
A stator housing has an annular wall including a first end, a second end, an outer surface and an inner surface defining an interior cavity. A stator is arranged within the interior cavity. The stator includes an outer surface portion, a first end turn and a second end turn. A coolant annulus extends about at least a portion of the stator housing. The coolant annulus includes at least one coolant spray passage arranged to direct a spray of coolant at one of the first end turn and the second end turn. A coolant seal and distributor is coupled to the stator housing at the first end sealing against the stator. The coolant seal and distributor includes one or more coolant spray nozzles arranged to direct a spray of coolant onto the other of the first end turn and the second end turn.