Stator Teeth Grooves Reduce Cogging Torque
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Solution Overview
Problem
Existing motors experience cogging torque and torque ripple due to differences in permeability between the stator core and air in slot openings, leading to noise and vibration issues.
Innovation Solution
The motor incorporates semicircular grooves on the stator teeth to increase the main cogging degree, reducing cogging torque and torque ripple by optimizing the groove width, radius, and position relative to the air gap, thereby enhancing motor quality and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If slot openings are formed between adjacent teeth to prevent flux leakage, then magnetic flux confinement is improved, but cogging torque increases due to permeability difference between stator core and air
Solution Approach 1:
The patent applies local quality by forming grooves only in specific regions of the teeth (at the tip or side surfaces) rather than uniformly across the entire tooth structure. This localized modification changes the magnetic permeability distribution specifically in the slot opening areas, reducing cogging torque while preserving the flux confinement function in other regions.
Solution Approach 2:
The patent changes the geometric parameters of the teeth by introducing grooves with specific dimensions (depth, width, shape) to modify the magnetic field distribution. By adjusting these parameters, the permeability difference between stator core and air in the slot opening is reduced, thereby decreasing cogging torque while maintaining flux confinement.
2Object-generated harmful factors
If grooves are formed on teeth to reduce cogging torque, then motor quality is improved, but manufacturing complexity increases
Solution Approach 1:
The patent employs curved or semicircular groove shapes rather than sharp angular cuts. This curvature simplifies the manufacturing process by allowing the use of standard milling or grinding tools with rounded edges, reducing tool wear, and improving surface finish quality while still achieving the desired magnetic field modification effect.
Solution Approach 2:
The patent applies partial action by forming grooves only in specific locations (tip or side surfaces of teeth) rather than throughout the entire tooth structure. This partial modification is sufficient to reduce cogging torque while minimizing the additional manufacturing complexity compared to complete tooth restructuring.
3Object-generated harmful factors
If groove radius is increased to reduce cogging torque, then permeability difference is reduced, but motor performance may deteriorate
Solution Approach 1:
The patent systematically investigates and optimizes the groove parameters (radius, depth, width, position) to find the optimal balance between reducing cogging torque and maintaining motor performance. By carefully controlling these parameters within specific ranges, the patent achieves significant cogging torque reduction while preserving sufficient motor output and efficiency.
Solution Approach 2:
The patent applies partial action by using moderate groove dimensions rather than extreme values. The groove radius is set to a specific range that provides enough magnetic field modification to reduce cogging torque but does not excessively remove material that would weaken the tooth structure or disrupt the magnetic circuit, thereby maintaining motor 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
The implementation significantly reduces cogging torque and torque ripple, improving motor quality while maintaining performance, as demonstrated by comparisons with motors without grooves or those with square notches.
Implementation Method 1
A motor is a device which obtains torque by converting electrical energy into mechanical energy
Implementation Method 2
the flux moves through a tooth side having high permeability while the rotor rotates
Implementation Method 3
torque pulsation may occur due to a difference in permeability in a slot opening area
Data Source
Figure 1
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AI summary
An embodiment relates to a stator and motor, the stator comprising: a stator core having teeth; and a coil wound on the teeth, wherein each tooth comprises a body around which the coil is wound, and a shoe connected to the body, and the shoe comprises a plurality of grooves, and the width of the grooves, which are in the circumferential direction, is 90-110% of the width of a slot opening between the teeth. In addition, the motor forms grooves on the teeth of the stator, increasing the main cogging differential, thereby providing the benefit of significantly reducing the cogging torque.