Corrugated Rotor-Shaft Coupling for Axial and Radial Load Relief
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Solution Overview
Problem
Existing electric machines, particularly in aircraft applications, face challenges in achieving a balance between energy efficiency, power-to-weight ratio, reliability, and service life, while also managing external forces such as axial and radial forces exerted on shafts due to side winds or propeller operation, which often require heavy and wear-prone mountings.
Innovation Solution
The electric machine incorporates a flexible coupling element with alternately curved connecting surfaces, allowing axial, radial translation, and tilting movements of the shaft relative to the stator, while transmitting torque between the rotor and shaft without the need for lubrication, thus enabling a compact, lightweight, and robust design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a stiff mounting is provided for the shaft to absorb axial and radial forces, then the shaft can withstand external forces, but the weight of the mounting increases
Solution Approach 1:
The patent employs a flexible coupling element with a bellows-like structure consisting of alternately curved connecting surfaces. This flexible membrane structure absorbs axial and radial forces through elastic deformation, replacing traditional stiff mountings and significantly reducing the weight of the mounting system while maintaining force absorption capability.
Solution Approach 2:
The coupling element's flexibility is achieved by controlling the geometry parameters of the alternately curved connecting surfaces, including the number, amplitude, and wavelength of curves. By optimizing these parameters, the coupling element can adaptively adjust its stiffness characteristics to absorb external forces while maintaining lightweight construction.
2Force
If a stiff mounting is provided for the shaft, then the shaft can withstand external forces, but wear on the components increases
Solution Approach 1:
The flexible coupling element made of elastomeric material absorbs forces through elastic deformation rather than rigid contact. This eliminates sliding friction and wear between mounting components, significantly improving reliability and service life of the shaft mounting system.
Solution Approach 2:
The patent replaces traditional mechanical mounting systems with sliding contacts and bearings that are prone to wear, with a flexible coupling element that absorbs forces through material elasticity. This substitution eliminates the need for lubrication and reduces wear-related failures.
3Weight of moving object
If a flexible coupling element with alternately curved connecting surfaces is used, then weight is reduced and wear is minimized, but the complexity of the coupling element increases
Solution Approach 1:
The coupling element is designed with a segmented bellows structure consisting of multiple alternately curved connecting surfaces. This segmentation allows the element to flex in multiple directions while maintaining a relatively simple overall form. The modular curved sections can be manufactured using standard forming processes, balancing structural flexibility with manufacturing simplicity.
4Adaptability or versatility
If the shaft is allowed to move axially and radially, then flexibility is improved, but the precision of shaft alignment decreases
Solution Approach 1:
The alternately curved connecting surfaces of the flexible coupling element provide controlled flexibility that allows shaft movement while maintaining alignment precision. The curved geometry is designed to accommodate thermal expansion and misalignment within specified tolerances, ensuring both adaptability and manufacturing precision are satisfied.
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 configuration enhances the electric machine's energy efficiency, reduces weight, and minimizes wear, while maintaining robust torque transmission and adaptability to various motor designs, making it particularly suitable for aircraft applications.
Implementation Method 1
The connecting surface of the coupling element forms a flexible bellows. The coupling element decouples the rotor from the shaft elastically in the axial and radial directions.
Implementation Method 2
a torque may be transmitted between the rotor and the shaft by the coupling element
Data Source
AI summary
The invention relates to an electric machine (1; 1′), comprising: a stator (10); a rotor (11) that can be rotated relative to the stator (10); a shaft (12) that can be rotated relative to the stator (10); and a flexible coupling element (13; 13′; 13″) having a first connecting section (130; 130′) fixed to the rotor (11) and a second connecting section (131; 131′; 131″) fixed to the shaft (12). which connecting sections have different diameters (D1, D2) and are connected to one another via an alternately curved connecting surface (132; 132′).