Electric Machine Shaft with Orbital Friction Welded Joints
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Solution Overview
Problem
Existing electrical machines are not cost-effectively adaptable to individual requirements due to material and shape-dependent connections, which limit their efficiency and mechanical stability.
Innovation Solution
The use of orbital friction welding for a cohesive and homogeneous connection between non-ferrous and ferrous metal sections of the shaft, allowing for a material- and shape-independent joint that meets mechanical and thermal stress requirements, enabling efficient power transmission and adaptation to various applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If material-dependent connection methods are used for joining shaft sections, then connection strength is improved, but adaptability to different material combinations deteriorates
Solution Approach 1:
The invention changes the fundamental parameter of the joining method from material-specific processes (welding, brazing, mechanical fastening) to a friction-based process that works universally across different material combinations. The friction connection method allows joining of shaft sections made from different materials (steel, aluminum, composite materials) without requiring material-matched connection technology, thus improving adaptability while maintaining connection strength through optimized friction surfaces and clamping forces.
2Adaptability or versatility
If complex connection structures are used to achieve shape-independent connections, then adaptability is improved, but device complexity deteriorates
Solution Approach 1:
The invention applies local quality by creating friction-optimized surfaces at specific locations on the shaft sections. Instead of making the entire shaft structure complex, only the connection surfaces are specially designed with appropriate friction coefficients, roughness, and geometry. This localized optimization enables shape-independent connections while keeping the overall device complexity low, as the friction connection mechanism itself remains simple and the special surface treatment is confined to small areas.
3Stability of the object's composition
If friction welding is used to connect shaft sections, then connection homogeneity is improved, but heat generation during joining increases
Solution Approach 1:
The invention converts the potentially harmful heat generation during friction connection into a beneficial effect. The friction heat generated during the joining process is used to temporarily reduce the friction coefficient, allowing the friction surfaces to slide smoothly and create a homogeneous connection. Once the connection is established and clamping force is applied, the surfaces cool and create a strong, homogeneous friction bond. This approach transforms the harmful heat into a useful tool for achieving uniform connection quality across the entire friction surface.
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 solution allows for the creation of electrical machines that are individually tailored to meet specific requirements at low cost, with improved mechanical stability, reduced material usage, and efficient heat dissipation, while maintaining high process reliability and cost-effectiveness in production.
Implementation Method 1
The first section and the second section are connected in an integral and homogeneous manner at the joint by orbital friction welding
Implementation Method 2
The first section is made of a low thermal conductivity stainless steel adapted to be supported in the bearings
Data Source
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AI summary
The invention relates to an electric machine (1, 200, 300) comprising a stator (2, 201), a rotor (4, 202) which magnetically interacts with the stator (2, 201) during operation of the electric machine (1, 200, 300), a first bearing device (8, 208), a second bearing device (81, 281) and a shaft (5, 25, 35) which is rotatably mounted in the first bearing device (8, 208) and the second bearing device (81, 281) about an axis of rotation (3) of the shaft (5, 25, 35), wherein the shaft (5, 25, 35) has successively in an axial direction (21) of the axis of rotation (3) a first section (301, 2301, 3301) with a first material and a second section (302, 2301) with a second material, wherein the rotor (4, 202) is attached to the first section (301,2301,3301) of the shaft (5,25,35) is attached, wherein the first material and the second material are joined in a material-bonded and homogeneous manner at a joint (9,209,309) of the first section (301,2301,3301) and the second section (302,2302),a shaft (5, 25, 35) for an electric machine (1, 200, 300), a rotor (4, 202) for an electric machine (1, 200, 300), a series (400) of electric machines (1, 200, 300) comprising at least one first electric machine (1, 200, 300) and at least one second electric machine (1, 200, 300), and a method for manufacturing an electric machine (1, 200, 300), as well as a method for manufacturing a series (400) of electric machines (1, 200, 300).