Electric Machine Cooling Assembly Rotor Stator Gap
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Solution Overview
Problem
Existing electric machine cooling systems, such as those described in U.S. Patent Application No. 2015/0048699, disrupt magnetic flux and cause excessive friction between the rotor and stator, leading to reduced performance and efficiency due to the positioning of cooling outlets and excess coolant.
Innovation Solution
A cooling assembly with an axial passage directing cooling oil along a shaft's longitudinal axis, angled passages redirecting oil to a gap between the rotor and stator, and arcuate grooves on the rotor's surface to efficiently distribute cooling oil and minimize magnetic flux disruption and friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a vertical cooling outlet is positioned within the rotor body, then cooling of the rotor body is improved, but the magnetic flux of the rotor body is reduced due to separation of laminations
Solution Approach 1:
The cooling outlet is repositioned from a vertical orientation within the rotor body to a horizontal orientation in the gap between the rotor and stator. This dimensional change allows the cooling function to be achieved without penetrating the rotor laminations, thereby preserving magnetic flux while maintaining cooling effectiveness through the alternative pathway in the radial gap.
2Temperature
If excess coolant is provided to the gap between the rotor and stator, then cooling coverage is improved, but friction between the rotor and stator increases
Solution Approach 1:
The coolant flow parameters are precisely controlled by designing specific flow paths and outlet configurations that deliver the exact amount of coolant needed for effective cooling. This parameter optimization ensures sufficient cooling coverage while preventing excess coolant from causing increased friction between the rotor and stator surfaces.
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 cooling assembly enhances heat dissipation and maintains magnetic flux integrity, reducing friction and improving the overall efficiency and performance of the electric machine by directing cooling oil effectively to heat-generating components without disrupting the magnetic field.
Implementation Method 1
an axial passage formed along a longitudinal axis of the shaft and configured to direct cooling oil from a first end of the shaft towards a second end of the shaft
Implementation Method 2
an angled passage fluidly connected to the axial passage and configured to redirect the cooling oil towards a gap between an outer surface of the rotor and an inner surface of the stator
Implementation Method 3
an arcuate groove formed along the outer surface of the rotor and configured to sling the cooling oil towards opposing ends of the rotor
Implementation Method 4
As coolant travels through the interior rotor cooling path and the exterior cooling path, the rotor body and the stator are gradually cooled
Data Source
AI summary
A cooling assembly is disclosed for use with an electric machine having a housing, a shaft rotatably supported within the housing, a rotor operatively coupled to rotate with the shaft, and a stator annularly surrounding the rotor. The cooling assembly may have an axial passage formed along a longitudinal axis of the shaft and configured to direct cooling oil from a first end of the shaft towards a second end of the shaft opposite the first end of the shaft. The cooling assembly may also have an angled passage fluidly connected to the axial passage and configured to redirect the cooling oil towards a gap between an outer surface of the rotor and an inner surface of the stator. The cooling assembly may further have an arcuate groove formed along the outer surface of the rotor and configured to sling the cooling oil towards opposing ends of the rotor.