Overmolded Cover With Flow Disruption Members for End Winding Cooling
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Solution Overview
Problem
Existing cooling methods for electric machine end windings result in inconsistent coolant coverage, leading to hot spots and inadequate heat removal, which can degrade the machine and reduce reliability.
Innovation Solution
A coolant chamber with flow disruption members is created between the stator and a cover, using a coolant fluid like hydrocarbon lubricant, which is supplied through passages and generates turbulence for enhanced heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a simple cover is used without flow disruption members, then the device complexity is reduced, but the coolant coverage becomes inconsistent leading to hot spots
Solution Approach 1:
The cover is designed with localized flow disruption members (ribs or protrusions) at specific positions where flow separation or dead zones are expected to occur. These local modifications create turbulence and improve coolant distribution in critical areas without requiring complete redesign of the entire cover structure, thus achieving consistent coolant coverage while maintaining manufacturing feasibility.
Solution Approach 2:
The flow disruption members are designed as simple geometric features (such as ribs or protrusions) that can be easily replicated during molding or manufacturing. By using standard geometric shapes that can be copied repeatedly, the complexity is minimized while still achieving the desired flow disruption effect for consistent coolant distribution.
2Temperature
If flow disruption members are added to the cover, then heat transfer is enhanced through turbulence, but the manufacturing complexity increases
Solution Approach 1:
The flow disruption members are designed as separate, discrete features that can be independently formed during the molding process. By segmenting the cover into regions with and without flow disruption members, the manufacturing process can use standard injection molding techniques with simple core pins or inserts to create the turbulent flow features, avoiding the need for complex multi-step manufacturing processes.
Solution Approach 2:
The flow disruption members are designed with optimized dimensions and spacing parameters that can be adjusted during the design phase to achieve the desired turbulence level. By carefully selecting parameters such as rib height, spacing, and angle, the heat transfer efficiency is maximized while keeping the manufacturing process simple and compatible with standard molding capabilities.
3Reliability
If coolant passages are added to the cover, then coolant supply is improved, but the device complexity increases
Solution Approach 1:
The cover is designed to serve multiple functions: it provides structural support for the end windings, defines the coolant chamber geometry, incorporates flow disruption members for turbulence generation, and includes integrated coolant passages for fluid distribution. By combining these functions into a single component, the overall system complexity is reduced compared to using separate parts for each function.
Solution Approach 2:
The coolant passages are integrated directly into the cover structure rather than being separate components. The passages are formed as hollow channels within the cover material itself, merging the fluid distribution function with the structural cover function. This integration eliminates the need for separate piping or mounting brackets, simplifying the overall assembly while ensuring consistent coolant supply to the coolant chamber.
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 solution provides consistent cooling to all end windings, preventing hot spots and improving the reliability and longevity of electric machines.
Implementation Method 1
The cover includes a plurality of flow disruption members extending from the inner surface into the coolant chamber
Implementation Method 2
provides consistent cooling to all end windings, preventing hot spots
Data Source
AI summary
An electric machine includes a stator. The stator has a plurality of slots defined between a plurality of laminated protrusions. A plurality of wire windings is disposed in the slots. The wire windings form end windings at respective ends of the stator. A cover is disposed about the end windings. A coolant chamber is defined between an inner surface of the cover and the stator. The cover includes a plurality of flow disruption members extending from the inner surface into the coolant chamber.