Abstract: Disclosed is a method of forming a shaped configuration by cold forging at an end of a long element, such as the armature shaft of a starter motor for an automobile. The die used in this method has an inner space in which a section for forming the shaped configuration is provided at one end portion thereof, and the diameter of the inner space gradually increases from the shaped configuration forming section to the other end portion of the inner space. A material is placed in the die from the other end portion of the inner space and, then, is forced into the die by a punch to be forged into the shape corresponding to that of the inner space of the die. After the forging, the shaped material is pushed out of the die by a knock-out pin which is inserted into the die in the opposite direction to the direction in which the material is forced.

Abstract: A shaft is cold-forged to have a shaped portion at one end of the shaft and a flange portion at a middle of the shaft. A taper portion is provided at a root of the flange portion on the opposite side thereof to the shaped portion. The shaped portion is formed by forward extrusion of a bar material, and the flange portion is formed by upsetting. The taper portion is formed by extruding the root of the flange portion to provide a gently inclined continuous connection between the flange portion and an adjacent portion of the shaft. The apparatus for manufacturing the shaft has at least a first set of dies, at least a second set of dies, and a conveyance system for transferring the shaft between the die sets.

Abstract: Disclosed is a method of forming a shaped configuration by cold forging at an end of a long element, such as the armature shaft of a starter motor for an automobile. The die used in this method has an inner space in which a section for forming the shaped configuration is provided at one end portion thereof, and the diameter of the inner space gradually increases from the shaped configuration forming section to the other end portion of the inner space. A material is placed in the die from the other end portion of the inner space and then, is forced into the die by a punch to be forged into the shape corresponding to that of the inner space of the die. After the forging, the shaped material is pushed out of the die by a knock-out pin which is inserted into the die in the opposite direction to the direction in which the material is forced.

Abstract: The starter motor includes a first output shaft with a pinion gear in mesh with a ring gear of an engine. A first reduction mechanism outputs power from a motor shaft through the first output shaft. A second output shaft and a second reduction mechanism output power from the first output shaft through the second output shaft. The second output shaft is rotatably coupled onto the first output shaft and made coaxial therewith. Power can be taken out on the side of the pinion gear. Both output shafts are associated with each other through a stop member for regulating relative displacement in the axial directions, so that thrusts in directions opposite to the above directions different from each other, which have not been borne, can be borne by each of the output shafts on the other side, respectively.