Electric Machine Cooling via Segmented Air Channels
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Solution Overview
Problem
Existing encapsulated electrical machines with air cooling systems face inefficiencies in heat dissipation, particularly in highly utilized scenarios, as the current internal cooling circuits do not effectively manage heat generated in the rotor and stator.
Innovation Solution
The electrical machine design incorporates multiple cooling channels and elements, including radially arranged first and second cooling channels, and axially extending third cooling channels, along with an outer ring element that deflects cooling air tangentially, enhancing heat dissipation through a combination of air guiding elements and materials with high thermal conductivity like aluminum, and utilizing cover elements with conveying elements to act as fans.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an internal cooling circuit is used to dissipate heat from rotor and stator, then heat dissipation is improved, but the cooling effectiveness is insufficient for highly utilized encapsulated machines
Solution Approach 1:
The cooling system is segmented into multiple independent cooling channels (first cooling channels in rotor shaft, second cooling channels in stator, third cooling channels in housing) that can be supplied with cooling air independently. This segmentation allows each channel to be optimized for specific cooling needs of different components, improving overall cooling effectiveness for highly utilized machines.
Solution Approach 2:
The patent introduces axial cooling channels (third cooling channels) in addition to the traditional radial cooling channels. This adds a new dimensional approach to heat dissipation by directing cooling air axially through the housing and stator, complementing the radial cooling paths and providing enhanced cooling capacity for high-utilization scenarios.
2Temperature
If multiple cooling channels are added to improve heat dissipation, then cooling effectiveness is improved, but device complexity increases
Solution Approach 1:
Multiple cooling channels (first, second, and third cooling channels) are merged into a single integrated cooling system that shares common cooling air supply and control mechanisms. The channels work together as a unified thermal management system, allowing improved heat dissipation without proportionally increasing system complexity through separate independent systems.
Solution Approach 2:
The cooling channels serve multiple functions: first cooling channels cool the rotor shaft and rotor windings, second cooling channels cool the stator windings, and third cooling channels provide additional axial cooling. This multi-functionality allows a single cooling system architecture to address thermal management needs of all major components, improving heat dissipation efficiency without requiring separate dedicated cooling systems for each 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
This configuration significantly improves heat dissipation efficiency by directing cooling air flow effectively through the machine, maintaining operational efficiency and potentially supporting emergency operations by acting as a fan, while maintaining a compact structural design.
Implementation Method 1
A cooling air flow, which is supplied to the first cooling channels via the air inlet, is deflected radially inward and supplied to the B-side through the rotor shaft
Implementation Method 2
Within the inner ring element, the cooling air flow, or the corresponding portion thereof, is deflected radially outwards and fed to secondary cooling channels
Implementation Method 3
Within the outer ring element, the corresponding portion 16b of the cooling air flow is deflected tangentially to the third cooling channels and thus fed to them
Implementation Method 4
utilizing cover elements with conveying elements to act as fans
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
An electric machine (1) has a rotor (2) mounted on a rotor shaft (3). The rotor shaft (3) is supported in bearings (4) so that the rotor (2) and the rotor shaft (3) can rotate about an axis of rotation (R). The rotor (2) is surrounded radially on the outside by a stator (5), and the stator (5) by a housing (7). Cover elements (8, 9) are arranged at the axial ends of the rotor (2) and stator (5), by means of which the rotor (2) and the stator (5) are encapsulated from the environment of the electric machine (1). One cover element (8) is surrounded radially on the outside and axially on the side facing away from the rotor (2) and stator (5) by an air guide element (12), the other cover element (9) by an inner ring element (13). Axially extending first and second cooling channels (14, 21) are arranged in the housing (7) or between the housing (7) and the stator (5). Axially extending rotor channels (20) are arranged in the rotor shaft (3) and/or in the rotor (2).The housing (7) has a radially external air inlet (15) through which a cooling airflow (16) is supplied to the first cooling channels (14). The cooling airflow (16), or at least a portion (16a) thereof, is supplied via the first cooling channels (14) to the air guide element (12) or to a space between one of the cover elements (8) and the air guide element (12), deflected radially inwards there, then supplied via the rotor channels (20) to the inner ring element (13) or to a space between the other cover element (9) and the inner ring element (13), deflected radially outwards there, supplied to the second cooling channels (21), and then guided axially through the electric machine (1) by means of the second cooling channels (21). Finally, it escapes into the surroundings of the electric machine (1).