Stator Teeth Curved Contour Reduces Cogging Torque
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Solution Overview
Problem
Existing electric motors face challenges in minimizing cogging torque while maintaining motor performance, as known techniques often result in compromised performance.
Innovation Solution
The electric motor design features a rotor and stator configuration with radially inwardly extending teeth on the stator, each with a curved contour and tapered portions, which reduces cogging torque by optimizing the radial dimensions and gap variations between the teeth and rotor magnets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional tooth configurations are used, then motor performance is maintained, but cogging torque is not minimized
Solution Approach 1:
The patent applies local quality by varying the radial dimensions of stator teeth at different locations. Specifically, the teeth have different radial heights at their root portions versus their tip portions, creating localized dimensional variations that reduce cogging torque while preserving overall motor performance through controlled local geometry modifications.
Solution Approach 2:
The patent implements parameter changes by modifying the radial dimensions of stator teeth and adjusting the gap variations between teeth and rotor magnets. These parameter adjustments—including varying tooth radial heights and optimizing air gap dimensions—reduce cogging torque while maintaining motor performance through controlled geometric modifications.
2Object-affected harmful factors
If tooth radial dimensions are optimized to reduce cogging torque, then cogging torque is minimized, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies segmentation by dividing the stator tooth into distinct zones with different radial dimensions—specifically, the root portion has a different radial height than the tip portion. This segmentation allows each zone to be optimized independently for cogging torque reduction while using standard manufacturing tolerances for each segment.
Solution Approach 2:
The patent implements parameter changes by modifying the radial dimensions of stator teeth and adjusting the gap variations between teeth and rotor magnets. These parameter adjustments—including varying tooth radial heights and optimizing air gap dimensions—reduce cogging torque while maintaining motor performance through controlled geometric modifications.
Data Source
AI summary
An electric motor comprising a rotor rotatable about a rotor axis and a stator at least substantially circumscribing the rotor is provided. The stator includes a generally toroidal core including a plurality of arcuately spaced apart, radially inwardly extending teeth. Each of the teeth presents a radially innermost face that extends along a curved contour. A portion of the contour has a radius of curvature that corresponds to a circle having a center. The center is radially offset from the rotor axis. Furthermore, each of the teeth includes a radially extending arm having an end and a crown extending relative to the end. The crown presents a pair of arcuately spaced apart endmost tips, each of which has a rotor-facing side. The rotor-facing side includes a tapered portion that turns away from the rotor.