EC Motor Rotor Lamination with Annular Casting Channel
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Solution Overview
Problem
The assembly of EC motors is complicated by the alternating arrangement of laminations, which requires precise alignment and limits the flow of casting compound to permanent magnets, making the process difficult and costly.
Innovation Solution
An annular channel connected via radial channels between the rotor shaft and the rotor lamination stack allows for improved flow and radial distribution of the casting compound, simplifying the assembly and reducing the need for precise positioning of permanent magnets, while also enhancing the stability of the rotor lamination stack.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If laminations are arranged alternately to facilitate casting of permanent magnets, then the casting process is enabled, but the assembly process becomes more difficult and time-consuming due to alignment requirements
Solution Approach 1:
The rotor is divided into a rotor lamination stack with individual laminations, each containing integrated radial channels. This segmentation allows the channels to be formed separately in each lamination during manufacturing, eliminating the need for complex post-assembly alignment while enabling effective casting compound delivery to permanent magnets.
2Stability of the object's composition
If narrow radial channels are used in individual laminations, then the lamination structure is maintained, but the flow of casting compound to permanent magnets is limited
Solution Approach 1:
The radial channels extend in the axial direction through multiple laminations, utilizing the third dimension (axial direction) to increase channel width and cross-sectional area. This dimensional approach allows the casting compound to flow more effectively to permanent magnets while maintaining the integrity of individual lamination structures.
3Manufacturing precision
If precise positioning of permanent magnets is required during assembly, then magnet placement accuracy is achieved, but the assembly process becomes more difficult and costly
Solution Approach 1:
The radial channels are integrated directly into the lamination structure, creating self-aligning pathways that guide the casting compound and permanent magnets into correct positions automatically during the casting process. This self-service mechanism eliminates the need for complex external positioning fixtures and reduces assembly complexity while maintaining precision.
4Ease of manufacture
If alternating lamination arrangement is used, then permanent magnet casting is facilitated, but fabrication costs increase due to alignment requirements
Solution Approach 1:
The radial channels are merged directly into the lamination structure itself, combining the structural function of laminations with the fluid delivery function of channels. This integration eliminates the need for separate alignment operations and reduces fabrication costs by enabling both structural integrity and effective casting compound delivery through a unified design.
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 facilitates the secure fixation of permanent magnets with reduced leakage risk and fabrication costs, improving the assembly efficiency and stability of the EC motor.
Implementation Method 1
an annular channel, which is connected to the pockets in a fluid-conducting manner via radial channels, each of which is formed of a plurality of channel sections formed in adjacent laminations of the rotor lamination stack, is formed between the rotor shaft and the wall of the passage opening for supplying a casting compound from the annular channel to the pockets
Implementation Method 2
The casting compound also provides electrical insulation
Data Source
AI summary
An EC motor for an electric hand tool having a stator in which a rotor is rotatably mounted, which comprises a rotor lamination stack, which has a passage opening and is formed of individual laminations, and a rotor shaft which is cast in the passage opening of the rotor lamination stack by means of a casting compound, and having a plurality of permanent magnets, which are received in the pockets formed in the rotor lamination stack. An annular channel, which is connected to the pockets in a fluid-conducting manner via radial channels, each of which is formed of a plurality of channel sections formed in adjacent laminations of the rotor lamination stack, is formed between the rotor shaft and the wall of the passage opening for supplying the casting compound from the annular channel to the pockets. A method is also provided for producing a rotor for an EC motor.