Rotor core and method of manufacturing the same

摘要

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.

主权项

1. A method of manufacturing a rotor core, the rotor core formed by laminating a plurality of core sheets each punched out from a magnetic thin metal strip, each of the core sheets including a shaft hole in a center, the shaft hole including keys protruding radially inward of the core sheet, the method comprising:
a first process of punching out punched holes in the thin metal strip by a first punch and a first die paired with the first punch, the punched holes forming outlines of the keys, the punched holes including inside areas located inside the shaft hole and outside areas continuous with the inside areas and located outside the shaft hole; a second process of punching out the shaft hole by a second punch and a second die paired with the second punch, the shaft hole continuous with the punched holes, the shaft hole including recesses to avoid the keys; and a third process of punching out outlines of the core sheets each provided with the shaft hole and laminating the core sheets.