Electric Machine Oil Cooling Layout for Full Stator Coverage
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Solution Overview
Problem
Existing oil cooling systems for electric machines face challenges in effectively cooling stator windings and stators, particularly due to parallel straight pipes increasing manufacturing costs and being inflexible for machines of different axial sizes, while annular pipes with axial connections complicate installation and scalability.
Innovation Solution
An oil cooling system with separate annular pipes at each end of the stator and an axial oil application part between them, using housing and stator walls to form a cooling channel, allowing direct cooling of stator windings and adaptable to various machine sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If parallel straight cooling pipes are used, then the manufacturing cost increases, but the cooling coverage is limited to the middle part of the stator
Solution Approach 1:
The cooling system is segmented into multiple independent annular cooling pipes (first annular cooling pipe, second annular cooling pipe, third annular cooling pipe) positioned at different axial locations. Each pipe serves a specific axial segment of the stator, enabling comprehensive cooling coverage from the first end part through the middle part to the second end part without requiring complex parallel pipe arrangements.
2Reliability
If annular cooling pipes with axial connecting pipe are used, then the cooling coverage is improved, but the installation complexity increases and adaptability to different axial sizes is reduced
Solution Approach 1:
The axial connecting pipe is eliminated by segmenting the cooling system into independent annular cooling pipes. Each annular cooling pipe can be independently installed at its designated axial position, simplifying the installation process while maintaining comprehensive cooling coverage across all axial segments of the stator.
Solution Approach 2:
The cooling system is designed to be dynamically adaptable to different axial sizes through adjustable positioning mechanisms. The annular cooling pipes can be positioned at different axial locations based on the specific dimensions of the electric machine, allowing the same cooling system design to be effectively adapted to electric machines of various axial sizes.
3Reliability
If annular cooling pipes with axial connecting pipe are used, then the cooling coverage is improved, but the adaptability to different axial sizes is reduced
Solution Approach 1:
By eliminating the fixed axial connecting pipe and using independent annular cooling pipes, the system gains flexibility to adapt to different axial configurations. Each annular cooling pipe can be independently positioned to match the axial dimensions of specific electric machine models, improving versatility without compromising cooling coverage.
4Ease of operation
If the cooling system is designed for specific axial size, then the installation is simplified, but the scalability to different dimensions is poor
Solution Approach 1:
The cooling system is designed with universal applicability across different electric machine dimensions. The annular cooling pipes can be configured at various axial positions and the number of pipes can be adjusted based on the specific axial size requirements, allowing a single cooling system design to serve multiple applications with different scalability requirements while maintaining simple installation procedures.
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
Enables efficient cooling of stator windings and axial segments with reduced manufacturing costs and simplified installation, adaptable to different electric machine dimensions, and improved cooling efficiency.
Implementation Method 1
an axial oil application part, located between the first end part and the second end part and formed by a housing inner wall and a stator outer wall, the axial oil application part receiving cooling oil from at least one of the first annular oil application pipe and the second annular oil application pipe
Implementation Method 2
an oil inlet, for receiving external cooling oil; a first annular oil application pipe, located at the first end part and in fluid communication with the oil inlet; a second annular oil application pipe, located at the second end part and in fluid communication with the oil inlet
Data Source
Figure 1
Figure 2
Figure 3A
AI summary
An oil cooling system for an electric machine are disclosed. The electric machine comprising a housing and a stator accommodated in the housing. The stator has a first end part and a second end part in an axial direction of the electric machine. The oil cooling system comprises an oil inlet, for receiving external cooling oil; a first annular oil application pipe, located at the first end part and in fluid communication with the oil inlet; a second annular oil application pipe, located at the second end part and in fluid communication with the oil inlet; an axial oil application part, located between the first end part and the second end part and formed by a housing inner wall and a stator outer wall, the axial oil application part receiving cooling oil from at least one of the first annular oil application pipe and the second annular oil application pipe.