Rotating Punch Relief Feature for Balanced IPM Rotor Laminations
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Solution Overview
Problem
Current methods for forming rotor cores for IPM motors are inefficient and costly due to the need for manual or servo motor-driven sub-die sets, which can result in inaccuracies and increased tooling costs, with a maximum rotational capability of 10-15°.
Innovation Solution
A rotating punch with a relief feature is used to form blanked laminates of electric steel, allowing for the formation of rotor cores with improved rotational balance and reduced cogging torque by varying the key rotational angles of the laminations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If manual or servo motor-driven sub-die sets are used to rotate laminations, then rotational capability is achieved, but tooling costs increase and manufacturing efficiency decreases
Solution Approach 1:
The punch automatically rotates the lamination through 180 degrees using its own movement during the punching operation, eliminating the need for separate rotation mechanisms. The lamination is rotated by the punching action itself, making the system self-servicing and improving manufacturing efficiency while maintaining rotational capability
Solution Approach 2:
The rotation function is merged with the punching operation. The punch that performs the cutting operation also performs the rotation, combining two functions into one operation. This eliminates the need for separate rotation mechanisms and reduces tooling complexity and costs
2Adaptability or versatility
If manual or servo motor-driven sub-die sets are used to rotate laminations, then rotational capability is achieved, but tooling complexity and costs increase
Solution Approach 1:
The system uses the existing punching mechanism to automatically rotate the lamination without requiring external rotation devices. The punch itself performs the rotation function, eliminating the need for complex sub-die sets with manual or servo-driven rotation mechanisms
Solution Approach 2:
The rotation function is integrated into the punching operation. The same punch that cuts the lamination also rotates it by 180 degrees, merging two functions into one component and operation, thereby reducing tooling complexity
3Stability of the object's composition
If 180 degree rotation of laminations is implemented, then weight balance is improved, but press speed decreases
Solution Approach 1:
The rotation action is performed continuously during the punching operation without interrupting the press cycle. The lamination is rotated by 180 degrees as part of the continuous punching action, maintaining press speed while achieving rotational balance
Solution Approach 2:
Rotation and punching are merged into a single continuous operation. The punch rotates the lamination while performing the cutting action, eliminating separate rotation steps and maintaining high press speed while achieving weight balance
Data Source
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Figure 4A~4D
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AI summary
Disclosed herein is a method for forming a rotor or stator core. The method includes the steps of: providing a plurality of key punches disposed about an inner diameter area of a sheet of electrical steel and circumferentially spaced from one another and activating a first key punch of the plurality of key punches to cut the electrical steel sheet to remove a portion to form a first key disposed at a first key rotational angle from the line of orientation from a plurality of key rotational angles.