Integrated Stator Cooling Jacket With Axial End-Turn Spray
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Solution Overview
Problem
Existing electric motor cooling systems are inefficient in removing heat from a larger surface area of the stator due to indirect contact and limited surface area, particularly in high-output systems installed in closed areas like motor vehicle engine compartments.
Innovation Solution
An integrated stator cooling system with a housing that includes a coolant flow path with circumferentially offset channels and end rings with coolant spray notches to direct coolant onto stator end turns, enhancing heat transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If coolant flows through a jacket radially outwardly of the stator, then heat is transferred from the end turns to the coolant, but the end turns have a relatively small surface area which limits cooling efficiency
Solution Approach 1:
The invention transitions from radial cooling (outward from stator center) to axial cooling (along the length of the stator). Coolant outlets are positioned at axial ends of the stator, directing coolant flow along the axial dimension onto end turns, thereby utilizing the full axial length of the stator for heat transfer rather than being limited to the radial surface area of end turns only
2Temperature
If heat flows from the stator through the housing into coolant, then cooling is achieved, but indirect contact between coolant and stator surface limits heat transfer capacity
Solution Approach 1:
The invention extracts the coolant flow path from the housing structure and integrates it directly into the stator laminations. Cooling channels are formed within the stator core itself, allowing coolant to flow in direct contact with the stator surface, eliminating the indirect cooling path through the housing and significantly improving heat transfer capacity
3Temperature
If the outer surface of the stator is cooled, then heat is removed, but the outer surface possesses a relatively small surface area when considered in relation to the overall area of stator laminations
Solution Approach 1:
The invention segments the stator core into multiple laminations with cooling channels distributed throughout. This segmentation allows coolant to access and cool multiple internal surfaces of the stator laminations simultaneously, vastly increasing the effective heat transfer surface area compared to cooling only the outer surface
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 increases heat shedding capacity by up to 50% and operational efficiency by 5% by exposing more stator surface area to cooling fluid, improving cooling efficacy.
Implementation Method 1
Heat may flow from the stator, through the housing, into the coolant passing through the cooling jacket
Implementation Method 2
The coolant may flow in a jacket arranged radially outwardly of a stator of the electric motor. Specifically, the coolant may flow through small openings in the housing down onto end turns of a stator winding
Data Source
AI summary
An electric machine includes a housing having an inner surface, an upper portion, and a bottom portion. The bottom portion supports a coolant inlet, and a coolant outlet. A stator is mounted in the housing. The stator includes a plurality of stator laminations having a first end turn and a second end turn. The plurality of stator laminations includes a coolant flow path having a plurality of coolant channels that extend circumferentially about the stator. A first portion of the plurality of coolant channels direct a coolant circumferentially about the stator in a clockwise direction and a second portion of the plurality of coolant channels direct the coolant circumferentially about the stator in a counter-clockwise direction. The coolant flow path includes a first outlet and a second outlet. The first outlet directs onto the first end turn, and the second outlet directs coolant onto the second end turn.