Abstract: A method for manufacturing a dynamoelectric machine frame according to which heat dissipating fins made of metallic sheet bent to provide a joining portion are placed on an outer peripheral surface of a cylindrical frame main body. A laser beam is irradiated in the direction parallel to the contact surface between the portion of the heat dissipating fins to be joined on the frame main body and the outer peripheral surface of the frame main body. Thus, the laser welding of the heat dissipating fins to the frame main body is achieved without large thermal distortion of the frame main body.

Abstract: A method of producing a frame body for an electric motor comprises a step of bending a flat plate having a given size into a generally round body, a step of pressing the generally round body in the radial direction by a metal mold having a given inner diameter, a step of welding edge surface portions opposing each other of the generally round body to form a cylindrical frame body, a step of attaching heat radiation fins on the outer circumferential surface of the frame body by welding, and a step of pressing the inner circumferential surface of the frame body in the radial direction so that the frame body has a predetermined inner diameter.

Abstract: A method of producing a motor for electric motor comprises a step of forming a heat radiation fin by bending a rectangular metallic plate, a step of forming a dummy fin having electrical conductivity, a step of disposing the heat radiation fin and the dummy fin on the outer circumferential surface of a frame body which has been formed in a cylindrical form so as to be symmetrical with respect to the axial centerline of the frame body, a step of disposing upper and lower core electrodes in the frame body so as to be in contact with the inner circumferential surface of the frame body and to respectively oppose the heat radiation fin and the dummy fin, a step or respectively connecting movable and stationary electrodes to the heat radiation fin and the dummy fin, and a step of melt-bonding only the heat radiation fin to the frame body by projection welding.

Abstract: A longitudinal seam welding apparatus for welding a longitudinal joint of a cylindrical main body of an electric motor frame comprises, on a base, a rigid tubular welding jig including a guide for engaging the joint of the frame main body to be welded for longitudinally guiding the frame main body, a hydraulic pusher for passing the main frame body through the welding jig, and a welding torch for seam welding the longitudinal joint of the frame main body.

Abstract: 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.

Abstract: An automatic welding apparatus for welding plate-like welding workpieces is provided wherein a weld line of the plate-like welding workpieces is detected, while a compressive force is being applied on the workpieces, by a detecting means which is adapted to be moved along the weld line, and a welding torch is moved in accordance with the results of the detection to carry out automatic welding of the workpieces.