Method for manufacturing a frame for an electric motor

摘要

A method for manufacturing a frame for an electric motor including a frame main body and a metallic member welded to the outer surface of the frame main body is disclosed. After metallic members such as cooling fins are attached to the outer surface of a hollow cylindrical frame main body by projection welding which results in distortion of the frame main body due to radial expansion, sizing is applied to the inner surface of the frame main body by applying a radially outward force from inside of the frame main body to remove the distortion and expand the frame main body so that the inner surface of the frame main body defines a true circle.