Curved Stator Tooth Core Geometry for Magnetic Saturation Relief
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Solution Overview
Problem
Magnetic saturation in stator cores of small-sized motors limits the increase in magnetic flux and output torque, hindering the improvement of motor performance.
Innovation Solution
The magnetic core design incorporates curved surface forming portions on the tooth main body to facilitate smoother magnetic flux flow, reducing magnetic resistance and local saturation, while maintaining the cross-sectional area and allowing for increased magnetic flux density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the stator core is reduced in size for small-sized motors, then the motor size is reduced, but magnetic saturation occurs more easily in the stator core
Solution Approach 1:
The invention introduces curved surface forming portions (first and second curved surfaces) on the tooth main body portion of the stator core. These curved surfaces replace sharp corners with smooth transitions, allowing magnetic flux to flow more uniformly without concentrating at corner regions. This curvature modification reduces local magnetic saturation while maintaining the compact size of the stator core, thereby resolving the contradiction between small motor size and magnetic saturation resistance.
2Power
If the magnetic flux is increased to improve output torque, then the output torque increases, but magnetic saturation occurs in the stator core
Solution Approach 1:
The curved surface forming portions create smooth transitions for magnetic flux paths, preventing flux concentration at corner regions. This allows higher magnetic flux to be generated without causing local saturation, enabling increased output torque while maintaining magnetic core reliability.
Solution Approach 2:
The invention applies local quality modification by adding curved surface forming portions specifically at the tooth main body portion where magnetic flux concentration occurs. This localized structural change addresses the saturation problem at critical regions without requiring overall enlargement of the stator core, allowing increased magnetic flux for higher torque output.
3Ease of manufacture
If a flat end surface and flat front surface are connected directly, then the manufacturing is simpler, but magnetic resistance increases near the corner
Solution Approach 1:
The invention replaces the direct connection of flat surfaces (which creates sharp corners) with curved surface forming portions. While this adds a slight manufacturing step, the curved surfaces dramatically reduce magnetic resistance by eliminating flux concentration at corners. The manufacturing complexity increase is minimal compared to the significant improvement in magnetic performance.
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 design enhances the output torque and efficiency of rotary electric machines by minimizing magnetic saturation and increasing the slot fill factor of the coil.
Implementation Method 1
A direction of the magnetic flux is a direction from the tooth main body portion toward the front surface of the core back portion or the back surface of the tooth leading end portion
Implementation Method 2
magnetic resistance in a magnetic circuit increases near the corner
Implementation Method 3
energization of a coil wound around the tooth main body portion generates a magnetic flux in the magnetic core
Data Source
AI summary
A magnetic core that includes: a core back portion including a front surface that faces in a first direction toward a rotation axis of a rotary electric machine; and a tooth portion. The tooth portion includes a tooth main body portion extending from the front surface in the first direction, and a tooth leading end portion at a leading end of the tooth main body portion. The tooth leading end portion includes a back surface facing in a direction opposite to the first direction. The tooth main body portion includes an end surface that faces in a second direction along the rotation axis. The end surface includes a curved surface having a depressed shape and that is connected to the front surface of the core back portion or the back surface of the tooth leading end portion.