Fiber-Composite Rotor Structure for High-Speed Magnet Stability
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Solution Overview
Problem
At high rotational speeds, the soft aluminum rotor body in existing electric motors deforms under centrifugal forces, leading to irreversible damage due to the deformation of magnets held in receptacles.
Innovation Solution
A rotor design featuring a stiffening element made of fiber composite material with star-shaped struts connecting the outer ring and rotor hub, which provides structural reinforcement and stability against deformation, allowing for the use of a lightweight yet robust rotor body that can withstand high speeds without significant deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a lightweight aluminum rotor body is used, then the rotor mass is reduced and acceleration is improved, but the rotor body deforms under centrifugal forces at high speeds
Solution Approach 1:
The patent applies composite materials by combining aluminum for the rotor body with fiber-reinforced plastic struts. The fiber strands (glass, carbon, or aramid) embedded in the plastic resin create a stiffening effect that prevents deformation under centrifugal forces while maintaining the lightweight advantage of aluminum. This composite construction resolves the contradiction between light weight and high-speed stability.
Solution Approach 2:
The rotor is segmented into functional components: the aluminum rotor body for light weight, the fiber-reinforced struts for structural strength, and magnet recesses for magnetic element placement. This segmentation allows each component to be optimized for its specific function while working together as a unified structure that achieves both lightweight design and deformation resistance.
2Device complexity
If magnets are held in receptacles in the rotor body, then the rotor structure is simplified, but the magnets deform the soft aluminum at high speeds causing irreversible damage
Solution Approach 1:
The patent applies local quality by making the struts locally stiffer where they contact the magnets. The fiber-reinforced plastic material provides concentrated structural support at the magnet interface zones, creating local stiffness exactly where needed to prevent magnet-induced deformation. This localized strengthening maintains overall structural simplicity while ensuring high-speed reliability.
Solution Approach 2:
The fiber-reinforced struts serve as pre-positioned structural reinforcement that cushions against the centrifugal forces and magnet pressures before damage can occur. The stiffening element is built into the rotor structure in advance, providing protective support that prevents irreversible deformation during high-speed operation rather than attempting to correct damage after it occurs.
3Strength
If a circumferential ring is added to reinforce the rotor body, then deformation resistance is improved, but the rotor mass increases
Solution Approach 1:
Instead of adding material in the circumferential direction (which would increase mass), the patent introduces reinforcement in the radial dimension through star-shaped struts that extend from the center hub to the outer circumference. This dimensional approach to strengthening provides deformation resistance through strategic structural geometry rather than through increased material quantity, maintaining lightweight design while achieving high strength-to-weight ratio.
Solution Approach 2:
The star-shaped struts utilize curved, spoke-like geometry that efficiently distributes centrifugal forces from the rotating magnets throughout the rotor structure. The curved form of the struts optimally channels the radial and tangential stresses, providing maximum strength with minimum material. This geometric optimization achieves deformation resistance without the mass penalty of a solid circumferential ring.
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
The rotor design enables reliable operation at speeds up to 40,000 to 50,000 rpm with minimal material usage, maintaining stability and preventing irreversible damage, while allowing for efficient production and assembly without additional adhesives.
Implementation Method 1
the magnets can deform the comparatively soft aluminum. Although it is also known to provide the rotor body with a circumferential ring made of a comparatively strong material in order to counteract possible deformation
Implementation Method 2
The stiffening element consists of a fiber composite material and was formed by winding a fiber strand. Since the struts are then also formed by the fiber strand, the struts can be loaded with a very large tensile force, which acts in a fiber direction of the fiber strand.
Data Source
Figure 1~2
Figure 3a~3c
AI summary
The invention relates to a rotor (10) for an electric motor, in particular a brushless disc rotor motor, synchronous motor, stepper motor or the like, and to a method for manufacturing a rotor, wherein the rotor has magnets (11) arranged on at least one axial side (12) of the rotor, wherein the rotor comprises a rotor body (13) forming receptacles (14) that hold the magnets, wherein the rotor body is formed with an outer ring (19) of a rotor hub (20) for coupling with a motor shaft of the electric motor, and a stiffening element (21) for connecting the outer ring and the rotor hub, wherein the stiffening element is formed with struts (22) extending star-shaped between the outer ring and the rotor hub, and wherein the stiffening element is formed from a fiber composite material with a fiber strand.