Rotor Core Fiber Winding With Tension Feedback to Limit Flux Leakage
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Solution Overview
Problem
In drive motors used for electric vehicles, the magnetic flux generated by a magnet inserted into the rotor core often leaks due to the magnet being formed integrally with the rotor core.
Innovation Solution
A winding apparatus for a rotor core that includes a fiber unwinder, guide roller assemblies, a tension roller assembly, and a core support, which together wind the entire outer surface of the rotor core with fiber material of appropriate tension, preventing magnetic flux leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the magnet is formed integrally with the rotor core, then the manufacturing process is simplified, but magnetic flux leaks from the magnet
Solution Approach 1:
The rotor core is divided into a core body and a separate magnet insertion groove structure. The magnet is inserted into the groove rather than being formed integrally, creating distinct segments that prevent magnetic flux leakage while maintaining manufacturing efficiency.
Solution Approach 2:
A fiber material is introduced as an intermediary substance between the magnet and the rotor core. This fiber material fills the magnet insertion groove and prevents magnetic flux from leaking from the magnet surfaces, resolving the harmful effect while keeping the integral manufacturing approach.
2Object-generated harmful factors
If the fiber material tension is increased to prevent magnetic flux leakage, then the magnetic flux leakage is reduced, but the winding process becomes more difficult to control
Solution Approach 1:
A tension roller assembly with a load cell is installed to measure the tension of the fiber material in real-time during the winding process. The measured tension data is fed back to a controller, which adjusts the drive motor speed to maintain optimal tension, preventing both excessive tension (which would make winding difficult) and insufficient tension (which would fail to prevent magnetic flux leakage).
Solution Approach 2:
The system dynamically adjusts the drive motor speed based on measured tension parameters. By changing the speed parameter in response to tension measurements, the system maintains the fiber material tension within an optimal range that effectively prevents magnetic flux leakage while keeping the winding process easy to control.
3Object-generated harmful factors
If the fiber material is wound tightly to increase surface tension, then magnetic flux leakage is prevented, but the fiber material may break during winding
Solution Approach 1:
The tension roller assembly continuously monitors fiber material tension and provides feedback to the controller. When tension approaches levels that could cause fiber breakage, the system automatically reduces drive motor speed, maintaining tension within a safe range that prevents both magnetic flux leakage and fiber material failure.
Solution Approach 2:
The system preemptively adjusts tension levels to prevent fiber material breakage before it occurs. By monitoring tension in real-time and making preventive adjustments to drive motor speed, the system cushions against the risk of fiber failure while maintaining sufficient tension to prevent magnetic flux leakage.
Data Source
AI summary
A winding apparatus for a rotor core may include a fiber unwinder that unwinds a fiber material for winding the rotor core. The winding apparatus may include a plurality of guide roller assemblies that guide the fiber material unwound from the fiber unwinder to the rotor core. The winding apparatus may include a tension roller assembly that is provided between the plurality of guide roller assemblies and measures a tension of the fiber material. The winding apparatus may include a core support that is provided so that the rotor core is rotatable with respect to a core shaft, the rotor core is movable in an axial direction of the core shaft, and the rotor core is tilted with respect to the core shaft.