Disc Rotor Stator Cooling Channels for Higher Power Density
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Solution Overview
Problem
Existing disc rotor machines face inefficiencies in heat transfer due to the use of casting compounds and long radial paths for heat dissipation, limiting their power density.
Innovation Solution
The implementation of a cooling channel section in the carrier wheel, which separates the holding and sealing functions from the cooling fluid guiding function, allowing for direct cooling of coil windings and efficient coolant circulation, using a plastic material for the carrier wheel and a metal sheet for the retaining ring for enhanced stability and manufacturing ease.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If guide plates are inserted and coils are potted together using potting compound, then the coils are passively cooled during operation, but sufficient heat transfer from the coil windings to the guide vanes is limited and the cooling efficiency is very inefficient
Solution Approach 1:
The stator is segmented into multiple independent coil assemblies, each with its own cooling channel section in the carrier wheel. This segmentation allows each coil to be directly cooled by coolant flowing through dedicated channels, eliminating the reliance on passive heat transfer through potting compound and guide plates, thereby significantly improving cooling efficiency and heat transfer effectiveness.
2Strength
If the guide vanes are made relatively long to provide structural support, then the radial path for heat dissipation becomes relatively long, but heat must be dissipated outward over this long radial path reducing cooling effectiveness
Solution Approach 1:
The cooling approach transitions from radial heat dissipation through long guide vanes to axial cooling through channels in the carrier wheel. The cooling channels are formed by axially extending separating elements that create cooling passages through the carrier wheel, allowing coolant to flow axially and directly cool the coil windings from the axial direction rather than relying on radial heat transfer through long structural components.
3Ease of manufacture
If the carrier wheel is formed from a stable metal sheet for robustness, then manufacturing complexity and cost increase, but if formed from plastic material, then ease of manufacture improves but structural stability may be compromised
Solution Approach 1:
The stator assembly uses composite construction where the carrier wheel is made from plastic material that is easily manufactured with integrated cooling channels, while the retaining rings are made from metal sheets for structural stability. The core segments are also made from metal sheets firmly connected to form a stable core structure. This composite approach allows the plastic carrier wheel to provide cooling functionality without compromising overall structural integrity, as the metal components provide the necessary strength and stability.
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 design achieves direct and efficient cooling of coil windings, increasing power density and ease of manufacturing, while maintaining robust torque support and coolant sealing.
Implementation Method 1
the cooling channel section (14) directly receives at least one of the coil windings (6)... direct cooling of the coils during operation is enabled
Implementation Method 2
redirect the cooling fluid along the coil windings... efficient circulation of the coolant
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
The invention relates to a disc rotor machine (1) for a motor vehicle drive, comprising a disc-shaped stator (2), the stator (2) having a plurality of core segments (5), which are distributed in a circumferential direction and are rigidly connected to one another by means of at least one retaining ring (3, 4), and a plurality of coil windings (6) each extending around a core segment (5). The disc rotor machine also comprises a rotor (7) which is mounted rotatably relative to the stator (2), the rotor (7) having a first rotor disc (8) arranged adjacent to the stator (2) towards a first axial side (10a) and a second rotor disc (9) arranged adjacent to the stator (2) towards a second axial side (10b) opposite the first axial side (10a), which rotor discs (8, 9) can be driven by a plurality of coils (11) of the stator (2) which are distributed in a circumferential direction and include the core segments (5) and coil windings (6). The disc rotor machine further comprises a cooling device (12) which cools the coils (11) during operation, the stator (2) having a carrier wheel (13) which accommodates the coil windings (6) and is connected to the at least one retaining ring (3, 4), the carrier wheel (13) forming a cooling channel portion (14) of the cooling device (12) that directly accommodates at least one of the coil windings (6).