Electric Motor Skew Angle Optimization for Winding Efficiency
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Solution Overview
Problem
Existing electric motor designs that form teeth or slots at an optimum skew angle face difficulties in winding efficiency due to large angles, degrading work efficiency while attempting to minimize cogging torque and torque ripple.
Innovation Solution
An electric motor design featuring a yoke with decentered segment-type permanent magnets and armature core with specific skew angles and groove configurations, allowing for minimized cogging torque and torque ripple without relying on the optimum skew angle derived from magnetic poles and slots, thus maintaining high work efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If teeth or slots are formed at an optimum skew angle to minimize cogging torque and torque ripple, then motor performance is improved, but the skew angle becomes too large making it difficult to wind winding wire around teeth, degrading work efficiency
Solution Approach 1:
The invention applies different skew angles to different parts of the armature core. Specifically, the teeth have a first skew angle while the slots have a second skew angle that is different from the first. This local differentiation allows each component to be optimized independently - the teeth can have sufficient skew to reduce cogging torque while the slots have a smaller skew that facilitates easier winding wire insertion and improves work efficiency.
Solution Approach 2:
The invention segments the skew angle parameter into two distinct values: one for teeth and another for slots. By dividing the armature core structure into these two functional zones with different skew characteristics, the design achieves a balance between reducing harmful magnetic effects and maintaining manufacturing efficiency.
2Object-affected harmful factors
If a large skew angle is used to minimize cogging torque, then torque ripple is reduced, but winding wire cannot be easily wound around teeth, degrading work efficiency
Solution Approach 1:
The invention applies different skew angles to different parts of the armature core. Specifically, the teeth have a first skew angle while the slots have a second skew angle that is different from the first. This local differentiation allows each component to be optimized independently - the teeth can have sufficient skew to reduce cogging torque while the slots have a smaller skew that facilitates easier winding wire insertion and improves work efficiency.
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 cogging torque and torque ripple while maintaining excellent motor efficiency and work efficiency, avoiding the inefficiencies associated with optimum skew angles.
Implementation Method 1
a magnetic field is formed at the teeth by the winding wire that is supplied with the electric power
Implementation Method 2
the armature is rotated by a magnetic suction force or repulsion force that occurs between the magnetic field and the permanent magnet provided on the yoke
Data Source
Figure 1
Figure 2
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AI summary
In an electric motor (2) which includes four permanent magnets (12) and in which the number of teeth (20) and the number of slots (23) are set to 6, when a polar arc angle of the permanent magnet (12) is θ1, and a skew angle of the teeth (20) and the slots (23) is θ2, the polar arc angle θ1 and the skew angle θ2 are set so as to satisfy 50° ≤ θ1 < 70° and 0° < θ2 ≤ 20°.