Motor Cooling Seal Assembly for Rotor Cavity Isolation
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Solution Overview
Problem
Existing electric motor cooling systems face challenges in sealing the stator cooling arrangement from the rotor cavity, leading to coolant leakage into the air gap, which results in drag losses and decreased motor efficiency.
Innovation Solution
A sealing assembly is developed using an elastomeric seal with a molded annular bead that is compressed between the stator and a sealing ring, creating a sealed cavity around the stator end windings, preventing coolant from entering the rotor cavity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If coolant is directed through interior cavities for stator cooling, then motor efficiency is improved through effective cooling, but coolant may leak into the air gap causing drag losses and decreasing motor efficiency
Solution Approach 1:
The cooling system is segmented into separate sealed cavities - a first sealed cavity for coolant flow and a second sealed cavity for the rotor. This segmentation prevents coolant from leaking into the air gap while maintaining effective cooling of the stator windings through dedicated coolant passages.
Solution Approach 2:
Sealing components (sealing ring, sealing sleeve, and elastomeric seal) act as intermediaries between the coolant cavity and rotor cavity. These sealing elements create fluid barriers that prevent coolant leakage into the air gap while allowing the cooling system to function effectively.
2Volume of stationary object
If sealing components are positioned at interfaces with minimal surface area, then the sealed cavity is compact, but sealing effectiveness is reduced increasing risk of coolant leakage
Solution Approach 1:
An elastomeric seal is used instead of rigid sealing components. The elastomeric material provides flexibility and compliance, allowing it to conform to the sealing surface and maintain effective sealing even in compact spaces with minimal surface area available for sealing.
Solution Approach 2:
The sealing system uses composite construction with a sealing ring, sealing sleeve, and elastomeric seal working together. This composite approach combines different material properties to achieve both compact dimensions and high sealing reliability.
3Reliability
If seal protrusion is used to extend past the interface into the rotor cavity, then sealing coverage is improved, but the seal degrades and increases risk of oil leakage
Solution Approach 1:
The elastomeric seal provides flexible sealing coverage without requiring protrusion into the rotor cavity. The flexibility of the elastomeric material allows it to maintain sealing effectiveness while remaining within the designated sealing interface, preventing degradation from protrusion.
Solution Approach 2:
The elastomeric seal acts as an intermediary that provides sufficient sealing coverage through its material properties rather than geometric protrusion. This eliminates the need for the seal to extend past the interface into the rotor cavity, preventing degradation.
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 sealing assembly effectively isolates coolant from the rotor cavity, reducing the risk of leakage and maintaining motor efficiency by ensuring consistent sealing pressure across varying temperature and pressure conditions.
Implementation Method 1
a molded annular bead arranged to define an inner diameter of the elastomeric seal and configured to be compressed axially to further separate a coolant for the plurality of end windings from a rotor
Implementation Method 2
an elastomeric seal interposed radially between a lateral surface of a stator of an electric motor and a sealing ring
Data Source
AI summary
Systems and methods for a sealing assembly for a motor cooling system are herein described. In one example, the sealing assembly includes an elastomeric seal interposed radially between a lateral surface of a stator of an electric motor and a sealing ring. The elastomeric seal includes a plurality of openings configured to receive a plurality of end windings of the stator and a molded annular bead arranged to define an inner diameter of the elastomeric seal and configured to be compressed axially to further separate a coolant for the plurality of end windings from a rotor.