Slip Ring Radial Openings for Cooling and Stability
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Solution Overview
Problem
Existing slip ring arrangements for electric machines face issues with mechanical stability and cooling efficiency, leading to surface deformation and increased vibrations at high power applications, requiring additional cooling surfaces and larger diameters.
Innovation Solution
The slip ring arrangement incorporates radial openings with a rounded rectangular cross-section, distributed homogeneously along the cylinder, which form passages for cooling media, reducing flow resistance and mechanical stress, and are manufactured using an erosion technique in combination with helical grooves to enhance cooling and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If helical grooves are added along the axial length of the slip ring to improve cooling, then cooling efficiency is improved, but mechanical stability deteriorates due to increased surface deformation in long term operation
Solution Approach 1:
The slip ring is segmented by introducing radial openings that divide the continuous helical groove into discrete cooling passages. This segmentation allows cooling functionality to be provided while maintaining the structural integrity of the remaining slip ring material, thus preventing surface deformation and mechanical instability.
Solution Approach 2:
Cooling passages are created only in specific localized regions through radial openings and selective groove formation, rather than creating continuous grooves along the entire axial length. This local quality approach provides cooling where needed while preserving the mechanical strength of the overall slip ring structure.
2Temperature
If additional cooling surfaces are added to improve cooling, then cooling efficiency is improved, but device complexity and outer diameter increase
Solution Approach 1:
Instead of adding cooling surfaces in the radial direction (increasing outer diameter), the invention creates cooling passages by extending grooves radially inward from the outer surface through radial openings. This dimensional approach to cooling provides adequate heat dissipation without increasing the overall outer diameter of the slip ring.
Solution Approach 2:
The cooling passages are nested within the existing slip ring structure by forming grooves that extend into the slip ring body through radial openings. This nesting approach incorporates cooling functionality inside the existing outer diameter, avoiding the need for additional external cooling 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
This design minimizes surface deformation and vibrations, ensuring mechanical stability and efficient cooling, reducing the need for large outer diameters and additional radial fans, while maintaining effective heat dissipation through self-ventilation.
Implementation Method 1
a cooling medium is led through the at least one passage formed by the grooves and the radial openings
Implementation Method 2
the radial openings are formed in the slip ring by an erosion technique
Data Source
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AI summary
The present disclosure relates to a slip ring arrangement for an electric machine to transfer current from a current source to a rotor of an electric machine. It is an object of the invention to provide a slip ring arrangement for an electric machine which guarantees appropriate cooling properties and mechanical stability. Disclosed is a slip ring arrangement for an electric machine with a slip ring composed of a cylindrical body, an end section and a shrink seat, whereas in the cylindrical body radial openings are formed, the shrink seat is shrinkable on a shaft, the shaft has a reduced diameter under the cylindrical body in order to form a sloped annular air gap beneath the cylindrical body to direct cooling medium through the radial openings.