| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for manufacturing a crank shaft, capable of easily and reliably preventing the lifetime of a holding die and a case from being shortened with a simple constitution. <P>SOLUTION: A crank shaft having a web part W of the predetermined thickness is manufactured by respectively holding a part forming a journal part of a material and a part p forming a pin part with circular hole parts 35, 36 of holding dies to press the parts in the axial direction and by molding the part w forming the web part to be squeezed between the holding dies. When manufacturing the crank shaft, at least one sectional shape of the part p forming the pin part of the material and the part forming the journal part is brought into contact with a bottom part (36a) of the circular hole parts 35, 36 of the corresponding holding die, and is molded into a shape for generating a gap to an opening part (36b) of the circular hole part 36 of the holding die 31. Then, pressurization in the axial direction of the material is started. <P>COPYRIGHT: (C)2012,JPO&INPIT |
