Additive Manufacturing Rotor with Material Gradient and Cooling Channels
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Solution Overview
Problem
Existing methods for producing rotors of electrical machines, such as copper die-casting and prefabricated copper rod insertion, face issues with tool wear, reduced conductivity due to contamination and voids, risk of cracks under centrifugal forces, and inability to achieve material gradients or optimize cooling structures like cavities and channels in short-circuit rings.
Innovation Solution
The method employs additive manufacturing with metal powder application (MPA) to create a rotor with a material-locking connection of cage bars and rings, allowing for a gradient of conductive materials and the integration of slots, channels, and cavities, using different materials like copper, steel, and titanium, and enabling supersonic powder deposition for efficient component construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper die-casting is used to produce cage bars and short-circuit rings, then the rotor can be manufactured with conductive material, but the tools have limited service life due to high thermal stress and the electrical conductivity is reduced due to contamination and voids
Solution Approach 1:
The patent replaces the mechanical die-casting process with additive manufacturing (MPA method). Instead of using traditional copper die-casting tools that suffer from thermal stress and limited service life, the invention uses a gas-powder mixture deposition process where metallic powder is introduced into a supersonic gas flow and deposited layer by layer. This substitution eliminates tool wear issues while maintaining electrical conductivity through controlled material deposition without contamination and voids.
2Ease of manufacture
If soldering or welding is used to attach short-circuit rings to cage bars, then the components can be connected, but cracks may form under centrifugal forces and vibrations
Solution Approach 1:
The patent merges the cage bars and short-circuit rings into a single integral component manufactured in one piece using additive manufacturing. Instead of separately manufacturing cage bars and short-circuit rings and then joining them through soldering or welding (which creates weak points prone to cracking), the invention deposits material continuously to form an integrated structure where the short-circuit ring and cage bars are monolithic, eliminating connection points and associated crack risks under centrifugal forces and vibrations.
Solution Approach 2:
The patent employs composite material deposition in the additive manufacturing process, using metallic powder that can include alloying elements and additives to enhance mechanical properties. The material composition can be optimized to provide both electrical conductivity and mechanical strength, creating a composite structure that resists cracking under operational stresses while maintaining ease of manufacture through automated layer-by-layer construction.
3Ease of manufacture
If the groove cross-section is not completely filled with copper, then the manufacturing process is simpler, but the rotor is less suitable for converter operation with immediate current application
Solution Approach 1:
The patent applies parameter changes by controlling the deposition parameters of the additive manufacturing process to achieve complete filling of groove cross-sections. By adjusting gas flow parameters, powder feed rate, and deposition layer thickness, the process ensures full penetration and complete filling of the groove spaces, eliminating voids and ensuring optimal electrical conductivity for converter operation while maintaining manufacturing simplicity through automated control.
4Adaptability or versatility
If traditional manufacturing methods are used, then the production process is established, but material gradients and optimized cooling structures like cavities and channels cannot be achieved in short-circuit rings
Solution Approach 1:
The patent applies local quality by enabling spatial variation of material properties within the short-circuit ring through additive manufacturing. The MPA method allows different metallic powders or alloy compositions to be deposited at different locations, creating material gradients where specific regions have optimized properties for their function (e.g., higher conductivity in current-carrying regions, enhanced strength in stress-bearing areas). This also enables integration of cooling cavities and channels directly into the structure during manufacturing, achieving functional optimization without significantly increasing process complexity.
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 approach enhances the rotor's efficiency and performance by achieving a material gradient, improved cooling, reduced centrifugal stress, and increased conductivity, allowing for higher speeds and better mass distribution, while enabling compact and integral connections.
Implementation Method 1
a metallic powder is introduced into a gas flow and this gas-powder mixture hits the product to be coated at supersonic speed
Implementation Method 2
The high kinetic energy of the powder particle is converted into heat on impact, causing the particle to stick
Implementation Method 3
subjecting it to a laser beam applied layer of the powdery metallic material
Data Source
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AI summary
The invention relates to a method for producing a rotor of an electric machine, which rotor is preferably designed as a squirrel-cage rotor. The end rings and/or squirrel-cage bars are produced by means of a metal powder application method. The invention further relates to an end ring for a rotor of an electric machine, said end ring in particular being produced by means of said method.