Stator Lamination with Movable Tips for Cogging Torque Reduction
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Solution Overview
Problem
The existing methods for manufacturing stators in electric machines face challenges such as non-uniform torque due to cogging torque, which leads to noise and vibration, and limit the amount of wire that can be used for coils, making the process slow and costly.
Innovation Solution
The use of laminations with strategically designed tips, including living hinges and pivotally connected portions, to create varying gaps between teeth, allowing for increased wire fill and reduced cogging torque by optimizing the winding process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If tips or protrusions are added to the radially inward teeth edges to reduce cogging torque, then cogging torque is reduced, but access to the cavities between adjacent teeth is further limited
Solution Approach 1:
The tip is designed with a movable portion that can change position between a first position (protruding from the tooth edge) and a second position (retracted). During motor operation, the tip protrudes to reduce cogging torque. During coil winding, the tip is retracted to allow needle access to the cavities between teeth. This dynamic repositioning resolves the contradiction between reducing harmful cogging torque and maintaining ease of coil formation.
2Ease of manufacture
If the needle needs to pass between adjacent teeth and tips to form coils, then coil formation is possible, but the process becomes slow and costly with limited wire amount
Solution Approach 1:
The movable tip design allows the tip to be retracted to a second position during coil winding, creating sufficient space for the needle to access and form coils without obstruction. This dynamic adjustment enables faster coil formation and allows for greater wire fill while maintaining the ability to form coils between teeth.
3Quantity of substance
If more wire is positioned about the stationary assembly to maximize slot fill, then motor power is increased, but access during winding becomes more difficult
Solution Approach 1:
By retracting the movable tip to its second position during the winding process, sufficient space is created for the needle to access and pack wire into the cavities between teeth. This enables maximization of slot fill with more wire while maintaining ease of operation during the winding process.
Data Source
AI summary
A lamination for use in an electric machine stator includes a body having a generally circular outer periphery and a generally circular inner periphery, spaced from the outer periphery and a plurality of spaced apart teeth extending inwardly from the circular inner periphery. Each of said teeth define opposed inner edges thereof. The lamination includes a first pair of tips extending tangentially in opposed directions from the inner edge of one of said teeth and a second pair of tips extending tangentially in opposed directions from the inner edges of another one of said teeth. A tip of the first pair of tips and a tip of the second pair of tips define a first configuration having a first gap therebetween and defining a second configuration having a second gap therebetween. The first gap being substantially less than the second gap.