Axial Flux Magnet Cooling with Stator Cover Spray Jets
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Solution Overview
Problem
Existing axial flux machines face challenges in efficiently cooling rotor magnets, leading to high temperatures that affect mechanical and magnetic performance, limit motor speed, and increase costs due to the use of higher temperature-grade magnetic materials.
Innovation Solution
An axial flux machine design that incorporates spraying elements on the stator cover to directly eject cooling fluid onto the rotor magnets through cooling channels, allowing for efficient heat transfer without modifying the rotor structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If air cooling is provided by impellor blades at the rotor side, then cooling is provided to the rotor, but direct cooling of the magnets is not possible and cooling efficiency is reduced
Solution Approach 1:
Instead of cooling the rotor from the rear side (away from stator), the invention inverts the approach by cooling the magnets from the front side (facing the air gap) through spraying elements on the stator. This allows direct cooling of the magnet surfaces that generate heat, improving cooling efficiency while maintaining simple integration into the existing stator structure.
2Temperature
If a sump with cooling fluid is used to submerge magnets, then improved cooling is obtained, but additional friction during rotation occurs and cooling efficiency is limited
Solution Approach 1:
The invention extracts the cooling fluid from a enclosed sump environment and delivers it directly to the magnet surfaces through spraying elements. This eliminates the need for the rotor to rotate through a fluid-filled sump, removing the harmful friction effect while maintaining effective direct cooling of the magnets.
3Reliability
If higher temperature grade magnetic material is used, then high temperature performance is improved, but machine cost increases substantially
Solution Approach 1:
The invention changes the thermal parameter of the system by introducing active cooling, thereby allowing the use of lower temperature grade magnetic materials. By controlling the magnet temperature through direct cooling, the system achieves reliable performance without requiring expensive high-temperature grade materials.
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
Enhances cooling efficiency, increases maximum rotational speed, reduces costs by using lower-grade magnets, and improves overall machine performance.
Implementation Method 1
one or more cooling channels adapted to guide a cooling fluid under pressure to the one or more respective spraying elements
Implementation Method 2
any of the spraying elements is adapted to eject cooling fluid towards the annular magnet zone, such that during operation with rotating rotor, the magnets are cooled by cooling fluid sprayed directly on the respective magnet surfaces
Implementation Method 3
the magnets are cooled by cooling fluid sprayed directly on the respective magnet surfaces
Data Source
AI summary
Axial flux machine includes a stator (100) and a rotor, where the stator (100) has a plurality of stator elements (204) enclosed by a stator housing. The stator housing has a first cover (103). The first rotor disk (101) has magnets (107) located in an annular zone (500). The stator (100) has one or more spraying elements (800) provided on the first cover (103), each of the spraying elements (800) having at least one exit hole, and one or more cooling channels (900) adapted to guide a cooling fluid under pressure to the one or more respective spraying elements (800). Any of the spraying elements (800) is adapted to eject cooling fluid towards the annular magnet zone (500), such that during operation with rotating rotor, the magnets (107) are cooled by cooling fluid sprayed directly on the respective magnet surfaces.