Electric Motor End-Ring Channel Fluid Diversion
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Solution Overview
Problem
Hybrid vehicle powertrains face inefficiencies due to spin losses in electric motors caused by fluid accumulation in the air gap between the rotor and stator, leading to reduced performance and increased energy consumption.
Innovation Solution
An electric motor design featuring an end-ring with an annular channel that diverts cooling fluid away from the air gap, utilizing a non-magnetic material like stainless steel or aluminum, and attached via press-fit, staking, or welding, to minimize spin losses by directing fluid flow effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling fluid is allowed to flow freely through the air gap for cooling purposes, then cooling effectiveness is improved, but spin losses increase due to fluid accumulation in the air gap
Solution Approach 1:
The end-ring is segmented into multiple functional zones: an inner circumference with channels for catching fluid, an outer circumference for fluid ejection, and vertical surfaces for directing flow. This segmentation allows different portions of the end-ring to perform distinct functions in managing fluid flow paths, separating cooling functions from spin loss prevention functions.
Solution Approach 2:
The end-ring acts as an intermediary component between the rotor and stator, intercepting cooling fluid before it can accumulate in the air gap and redirecting it through controlled paths. The annular channels and vertical surfaces on the end-ring mediate the fluid flow, allowing the system to maintain cooling while preventing harmful fluid accumulation.
2Loss of energy
If fluid is diverted away from the air gap using end-ring channels, then spin losses are reduced, but cooling effectiveness may be compromised
Solution Approach 1:
Different regions of the end-ring are given different properties and functions: the inner circumference has channels for fluid interception, the outer circumference has ejection features, and vertical surfaces direct flow. This local differentiation ensures that fluid is diverted from the air gap in critical areas while maintaining cooling flow in other regions.
Solution Approach 2:
The end-ring utilizes vertical surfaces extending axially to redirect fluid flow in a new dimension. By creating vertical flow paths and using the axial dimension for fluid redirection, the system can divert fluid away from the air gap while still maintaining cooling effectiveness through multi-dimensional flow management.
3Loss of energy
If an end-ring with annular channels is added to divert fluid, then spin losses are limited, but device complexity increases
Solution Approach 1:
The end-ring serves multiple functions simultaneously: it provides structural support for the rotor, acts as a fluid interception barrier through its channels, directs fluid flow via vertical surfaces, and ejects fluid through the outer circumference. This multi-functionality reduces the need for separate components, offsetting the added complexity with consolidated design benefits.
Solution Approach 2:
The patent merges the fluid diversion function with the existing end-ring structural component of the rotor. Rather than adding a separate fluid management device, the end-ring is designed to perform both its traditional structural role and the new fluid diversion function, combining multiple purposes into a single integrated component.
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 significantly reduces spin losses and enhances the operational efficiency of the electric motor by preventing fluid accumulation in the air gap, thereby improving the overall performance and longevity of the motor.
Implementation Method 1
The electric motor is cooled by gravity feed via a fluid flowing onto and past the stator windings, from the windings to the rotor, and from the rotor back to the stator
Implementation Method 2
a fluid flowing onto and past the stator windings, from the windings to the rotor
Implementation Method 3
The electric motor is cooled by gravity feed via a fluid flowing onto and past the stator windings
Data Source
AI summary
An electric motor includes a rotor and a stator. The stator is fixed with respect to the drive-unit housing and includes windings, and the rotor is configured to rotate inside the stator about an axis. An air gap is defined between the rotor and the stator. The electric motor also includes an end-ring fixed to the rotor for rotation therewith. The electric motor is cooled by gravity feed via a fluid flowing onto and past the stator windings, from the windings to the rotor, and from the rotor back to the stator. The end-ring includes an annular channel configured to catch the fluid flowing from the windings to the rotor and divert the fluid away from the air gap as the fluid flows from the rotor back to the stator, thereby limiting spin losses in the electric motor. An electro-mechanical drive-unit employing the above-described electric motor is also disclosed.