Method and apparatus for grooving on rotor

摘要

Grooves are formed on a rotor by rotor holders for holding a rotor at both ends of a rotary shaft thereof, a groove rolling die for forming grooves in the outer surfaces of the field cores of the rotor, and a holder die having a groove pattern in conformity with a pattern of the grooves that are formed in the outer surfaces of the field cores by the groove rolling die. When the grooves are formed, the grooves are uniform in depth over the entire length of the magnetic poles from the root to the top, thereby preventing the eddy-current loss reduction effect from being deteriorated.