Plastic-Magnet Rotor Flange for Stable Permanent Magnet Positioning
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Solution Overview
Problem
Current electric motor rotors with permanent magnets experience axial movement due to centrifugal forces, leading to unbalancing and mechanical noise, and the use of springs and laminettes complicates manufacturing and assembly.
Innovation Solution
A rotor design where at least one flange is made of plastic material with magnetic particles, integrated with permanent magnets, and the other flange is metal, ensuring balanced density and reducing relative movement of magnets during operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If springs and laminettes are used to hold permanent magnets in position, then magnet stability is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent merges the magnet retaining function with the flange structure by integrating retaining protrusions directly into the flange. This eliminates the need for separate springs and laminettes, reducing structural complexity while maintaining magnet stability during rotor operation.
Solution Approach 2:
The patent replaces the spring-based mechanical retention system with a rigid flange structure that has integrated retaining protrusions. This substitution eliminates the need for elastic components and simplifies the overall mechanical system while providing reliable magnet positioning.
2Manufacturing precision
If springs and laminettes are used to retain permanent magnets, then magnet positioning is improved, but manufacturing and assembly complexity increase
Solution Approach 1:
The retaining protrusions are integrated directly into the flange structure, combining the positioning and retaining functions into a single component. This reduces the number of parts to be manufactured and assembled, simplifying both production processes while maintaining precise magnet positioning.
3Reliability
If permanent magnets are held by springs and laminettes, then initial magnet stability is improved, but rotor balancing deteriorates over time
Solution Approach 1:
The patent replaces the spring-based retention system with a rigid flange structure that provides consistent mechanical support for the magnets. This eliminates the progressive degradation of supporting force that occurs with spring fatigue, maintaining both magnet stability and rotor balance throughout the operational life of the motor.
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 simplifies assembly, reduces mechanical noise, and improves rotor balancing by eliminating magnet movement and matching the density of metal flanges for enhanced stability.
Implementation Method 1
As the rotor rotates, the permanent magnets are subjected to centrifugal force. Therefore, if the magnets were not held in position inside the cavities of the rotor body, they would tend to move in an axial direction within the cavities.
Implementation Method 2
the density of the plastic flange being substantially equal to the density of the metal flange
Data Source
Figure 1~2
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AI summary
The invention relates to a rotor (10) for an electric motor (30), comprising: - a rotor shaft (12) mounted so as to be able to rotate about an axis (X); - a stack of laminations (14) mounted coaxially on the rotor shaft (12), the stack of laminations (14) comprising a plurality of inner recesses (15); - a plurality of permanent magnets (16) accommodated inside the inner recesses (15) of the stack of laminations (14); - a front flange (17) and a rear flange (19) mounted coaxially on the rotor shaft (32) and arranged axially to either side of the stack of laminations (14); in which at least one of the front and rear flanges (17, 19) is formed from a plastic material and is integral with the plurality of permanent magnets (16), each permanent magnet (16) being formed from a matrix made from plastic material incorporating particles having magnetic properties.