External Rotor Flux Return Ring With Elastic Magnet Clamping
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Solution Overview
Problem
Existing methods for attaching permanent magnets to external rotor motors require additional fixing elements and adhesives, increasing costs and assembly complexity, while adhesives can lead to contamination and process inefficiencies.
Innovation Solution
A return ring with radially distributed receptacles on its inside surface, featuring integrally formed bending legs that elastically and plastically deform to clamp permanent magnets, eliminating the need for additional fixing elements and adhesives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional fixing elements and adhesives are used to attach permanent magnets to the return ring, then the fastening reliability is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The fixing function is merged into the return ring itself through integrally formed bending legs. The bending legs are directly formed on the return ring and perform both the structural support function and the fastening function by elastically deforming to clamp the permanent magnets, eliminating the need for separate fixing elements and adhesives.
Solution Approach 2:
The bending legs perform self-service by using their own elastic deformation capability to provide the fastening force. When the permanent magnets are inserted, the bending legs automatically deform elastically to exert clamping force and secure the magnets in place without requiring additional fixing mechanisms or adhesive application processes.
2Reliability
If additional fixing elements and adhesives are used to attach permanent magnets, then the fastening reliability is improved, but the manufacturing cost and assembly effort increase
Solution Approach 1:
The fastening function is combined with the return ring structure through integrally formed bending legs. This merging eliminates the need for separate fixing elements and adhesives, reducing the number of parts, manufacturing steps, and associated costs while maintaining reliable fastening through the elastic clamping action of the bending legs.
Solution Approach 2:
The harmful and costly elements (adhesives and additional fixing elements) are extracted from the fastening system. By removing these unnecessary components and replacing them with the integrated bending leg mechanism, the manufacturing process is simplified and costs are reduced while maintaining fastening reliability.
3Reliability
If adhesives are used to attach permanent magnets, then the fastening reliability is improved, but contamination of mounting fixtures occurs and productivity decreases
Solution Approach 1:
The chemical bonding method (adhesive) is replaced with a mechanical fastening system using elastic bending legs. The bending legs exert clamping force through elastic deformation to secure the permanent magnets mechanically, eliminating the need for adhesives and thereby preventing contamination of mounting fixtures and improving productivity.
Solution Approach 2:
The bending legs provide self-service fastening through their elastic deformation capability. When permanent magnets are inserted into the receptacles, the bending legs automatically deform and exert clamping force to secure the magnets, eliminating the need for adhesive application processes and associated contamination risks.
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
Provides a cost-effective and efficient fastening method for permanent magnets, enhancing performance and heat dissipation by eliminating the need for adhesives and additional parts, while allowing for dimensional tolerance and compact design.
Implementation Method 1
Each of the receptacles has at least one bending leg formed integrally on the return ring, which is at least elastically bendable in the circumferential direction. Due to its elastic bendability, the at least one bending leg is designed to exert a clamping force on the respective permanent magnet for fastening it in the receptacle.
Implementation Method 2
In addition to elastic bending, the bending legs can also be plastically deformable, whereby when the respective permanent magnet is inserted, the bending legs experience not only the elastic clamping force but also an interference fit in the respective receptacle caused by the plastic deformation.
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a flux return ring for an electrical external rotor motor, with receptacles distributed on the radially inner side in the circumferential direction of the flux return ring and intended to fasten in position a permanent magnet each, wherein each of the receptacles has at least one bending limb formed integrally on the flux return ring, which bending limb is at least elastically bendable in the circumferential direction and designed to exert a clamping force on the corresponding permanent magnet in order to fasten the permanent magnet that can be arranged in the corresponding receptacle.