PRESS FORMING DEVICE, PRESS-FORMING METHOD USING SAME, AND ROTOR CORE OF ALTERNATING-CURRENT GENERATOR FOR AUTOMOBILE MANUFACTURED USING THIS PRESS-FORMING METHOD

摘要

[Problem] To achieve a press-forming device with which, when a steel rod-shaped projection having a tapered shape is press-formed, burrs generated between the projection and a back surface tool can be reduced without requiring an advanced lubricating film, and the forming of a back- surface part can be performed more suitably, and the service life of the forming tool can be prolonged. [Solution] A device for press-forming a steel rod-shaped projection having a tapered tip, the device being characterized in that a preformed material to be processed (31a) is held in a back surface tool (32) and a freely rotating rotary roll (41) is rolled toward the tapered tip part of this material to be processed (31a) while being pressed against this material to be processed, thereby plastically deforming the material to be processed (31a) to form a tapered shape.