Motor Rotor Endplate With Soft Magnetic Core for Flux Redirection
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Solution Overview
Problem
Existing motor rotors experience efficiency and counter electromotive force deterioration due to magnetic flux leakage in the axial direction of permanent magnets, which current technologies have not adequately addressed.
Innovation Solution
A rotor design incorporating a rotor core with accommodation holes for permanent magnets, an endplate made of non-magnetic material, and a soft magnetic core that redirects magnetic flux paths, reducing leakage by switching the direction of magnetic flux from axial to torque magnetic flux, thereby improving efficiency and counter electromotive force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If permanent magnets are disposed in the rotor core without additional restriction members, then the structure is simplified and component count is reduced, but magnetic flux leaks in the axial direction causing deterioration in efficiency and counter electromotive force
Solution Approach 1:
A soft magnetic core is introduced as an intermediary component between the permanent magnets and the air gap. This soft magnetic core provides a low-reluctance path for magnetic flux, preventing flux leakage into the air while maintaining structural simplicity. The soft magnetic core acts as a mediator that guides the magnetic flux along the desired path through the rotor core.
Solution Approach 2:
The rotor structure is segmented into distinct functional components: the rotor core with accommodation holes for permanent magnets, and a separate soft magnetic core layer. This segmentation allows each component to perform its specific function optimally - the rotor core provides mechanical support and magnet accommodation, while the soft magnetic core manages magnetic flux paths.
2Productivity
If magnetic flux is allowed to leak into the air from the end of the permanent magnet, then the motor structure is simpler, but efficiency and counter electromotive force deteriorate
Solution Approach 1:
The soft magnetic core serves as a magnetic flux mediator that intercepts leakage flux before it enters the air gap. By providing an alternative low-reluctance path through the soft magnetic material, the flux is guided back into the productive magnetic circuit, thereby improving motor efficiency without requiring complex restriction members.
3Reliability
If anti-withdrawal binders are provided to prevent withdrawal of permanent magnets, then magnet fixation is improved, but motor structure becomes more complex and component count increases
Solution Approach 1:
The soft magnetic core is merged with the rotor core structure, forming an integrated magnetic circuit component. This integration eliminates the need for separate anti-withdrawal binders, as the soft magnetic core itself provides both magnetic flux management and mechanical retention functions through its positioning and magnetic properties.
Solution Approach 2:
The soft magnetic core performs multiple functions simultaneously: it provides a low-reluctance path for magnetic flux, prevents magnetic flux leakage into the air gap, and mechanically retains the permanent magnets in their accommodation holes. This multi-functionality reduces the overall component count while maintaining reliability.
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
The design effectively minimizes magnetic flux leakage, enhances motor efficiency, and increases counter electromotive force while simplifying the motor structure and reducing component count by eliminating the need for separate restriction members.
Implementation Method 1
A rotor design incorporating a rotor core with accommodation holes for permanent magnets, an endplate made of non-magnetic material, and a soft magnetic core that redirects magnetic flux paths, reducing leakage by switching the direction of magnetic flux from axial to torque magnetic flux
Data Source
AI summary
A rotor for a motor includes: a rotor core including accommodation holes penetrating the rotor core in an axial direction; permanent magnets respectively accommodated in the accommodation holes; an endplate configured to cover an end of the rotor core; and a soft magnetic core disposed on the endplate.