Offset-Protrusion Rotor Assembly for Low-Runout Adhesive Bonding
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Solution Overview
Problem
Existing rotors for brushless DC machines face issues with mechanical strength against centrifugal forces and require extensive quality controls to maintain adhesive gaps, leading to runout errors and increased manufacturing costs.
Innovation Solution
A rotor design with a hollow cylindrical base body featuring radial protrusions offset by a defined angle, allowing for a defined adhesive gap and ensuring optimal adhesive distribution, which minimizes play and runout errors without additional spacer particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If separate production processes are used for the core and the winding, then manufacturing flexibility is maintained, but assembly precision and productivity are reduced
Solution Approach 1:
The patent merges the core production process and the winding production process into a single integrated device. The core assembly unit and winding assembly unit are combined in one machine, allowing simultaneous production of the core and winding components. This eliminates the need for separate production lines and manual transfer operations, directly increasing assembly speed and productivity while reducing overall device complexity through integration.
2Manufacturing precision
If separate production processes are used for the core and the winding, then manufacturing flexibility is maintained, but assembly precision is reduced
Solution Approach 1:
The integrated device allows the core and winding to be produced and assembled in a coordinated manner within the same production environment. The positioning mechanisms and alignment systems in the integrated device ensure precise relative positioning between core and winding components, achieving high assembly precision that would be difficult to maintain across separate production processes.
3Strength
If a solid rotor structure is used, then mechanical strength is improved, but adaptability for different pole pairs is reduced
Solution Approach 1:
The rotor is segmented into multiple independent magnetic pole pieces that are arranged around the rotor periphery. Each magnetic pole piece can be independently positioned and secured to the rotor core using retaining elements. This segmentation allows the rotor to be configured for different pole pairs by simply repositioning or reconfiguring the magnetic pole pieces, maintaining mechanical strength through the segmented structure while providing adaptability for different pole pair requirements.
Data Source
Figure 1a~1b
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AI summary
The invention relates to a rotor (18) for an electric machine (10), in particular for a brushless DC motor (12), comprising a hollow cylindrical main body (20) that is rotationally fixed to a machine shaft (16). According to the invention, the main body (20) comprises a plurality of radial protrusions (48) arranged over its casing surface in the circumferential direction (U) and in the axial direction (A) and offset relative to one another by a defined offset angle (V), wherein each radial protrusion (48) is limited over an angular range (W), which is smaller than the offset angle (V), and wherein the hollow cylindrical main body (20) is permanently connected, in particular adhered, to a hollow cylindrical body (26) surrounding same in the circumferential direction (U) by means of a joining process. The invention also relates to a method for producing a rotor (18) for an electric machine (10) comprising the following steps: using rotor laminations (50) for a rotor lamination stack (52) of the rotor (18), wherein a plurality of rotor laminations (50) have a respective at least one radial protrusion (48) that is limited over an angular range (W); stacking the rotor laminations (50) to form the rotor lamination stack (52) in such a way that, of the plurality of rotor laminations (50) having at least one radial protrusion (48), neighbouring rotor laminations (50) are rotated relative to one another about a defined offset angle (V) that is greater than the angular range (W) of the at least one radial protrusion (48); applying a joining means (54), in particular an adhesive, to an outer casing of the rotor lamination stack (52), preferably between the radial protrusions (48), and/or to an inner surface of a hollow cylindrical body (26); and sliding the hollow cylindrical body (26) onto the rotor lamination stack (52). The invention also relates to an electric machine (10) comprising a corresponding rotor (18), as well as an electrical processing device having a corresponding electric machine (10).