Rotor Core Manufacturing via Segmented Punching for Precision
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Solution Overview
Problem
Existing methods for manufacturing rotor cores with inward protruding keys are complex, reduce positional accuracy, and do not effectively manage wear of punches and dies, leading to thickness deviations and magnetic inhomogeneity.
Innovation Solution
A method involving separate punching processes for forming key outlines and shaft holes using paired punches and dies, with specific angular positions and auxiliary holes to prevent metal clippings and ensure precise lamination, maintaining constant physical properties and reducing stress concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If keys are formed by rotating punch and die during shaft hole formation, then keys are formed in shaft hole, but mechanical configuration becomes extremely complex and positional accuracy of keys is reduced
Solution Approach 1:
The patent divides the key formation process into two separate operations: first punching out the shaft hole with a simple circular punch, then separately forming keys by punching radial protrusions from the shaft hole perimeter. This segmentation eliminates the need for complex rotating mechanisms while maintaining precise key positioning through controlled punch movements from a stationary die.
Solution Approach 2:
The shaft hole is formed first as a preliminary step before key formation. The circular shaft hole is punched out first, providing a stable base from which keys are subsequently formed by radial punching operations. This preliminary action simplifies the overall process by establishing the main geometry before adding key features.
2Manufacturing precision
If shaft hole and keys are formed by rotating punch and die, then keys are formed, but accuracy between shaft and shaft hole is reduced
Solution Approach 1:
The formation of the shaft hole and keys are segmented into separate operations. The shaft hole is formed first by a simple circular punch, ensuring high circularity and perpendicularity. Keys are then formed separately by radial punching, maintaining their positional accuracy relative to the already-formed shaft hole without requiring complex coordinated rotation.
Solution Approach 2:
Instead of forming keys by rotating the punch and die together during shaft hole formation, the patent inverts the approach: the shaft hole is formed first by a stationary circular punch, and then keys are formed by radial punching operations from the shaft hole perimeter, reversing the conventional sequence to improve accuracy.
3Ease of manufacture
If punch and die are used to form shaft hole with keys, then keys are formed, but wear of punch and die increases and metal clippings are made
Solution Approach 1:
The punching process is segmented into two stages: first punching the shaft hole with a circular punch, then separately punching the keys with radial punches. This segmentation allows each punch to be optimized for its specific function, reducing overall wear. The separate key formation also controls metal flow to minimize clipping generation compared to forming keys during a single complex operation.
Solution Approach 2:
The shaft hole is formed as a preliminary operation before key formation. This preliminary punching establishes the main geometry with a simple circular punch, and subsequent key formation uses smaller radial punches that experience less stress and wear, extending tool life and reducing metal clipping.
Data Source
AI summary
A method of manufacturing a rotor core includes a first process of punching out punched holes 22, 23 forming outlines of keys 13, 14 in a thin metal strip 18, the holes 22, 23 including inside areas 25 located inside a shaft hole 12 and outside areas 26 continuous from the areas 25 and located outside the hole 12; a second process of punching out the hole 12 including recesses 35, 36 to avoid the keys 13, 14 and communicating with the holes 22, 23; and a third process of punching out an outline of a core sheet 11 having the hole 12 and laminating the sheets 11. Thereby, a shaft hole having keys is formed precisely, a thickness deviation of core sheets is eliminated, and a rotor core having homogeneous magnetism is provided.