PURPOSE: To shorten a machining required time by pressing an initial material with a die, and forming a projection part of raw material projecting from a circumferential edge boundary part of the die due to the expanding elongation of this initial material with a roll relatively rotating against the die to a dish like body so as to be curved toward a drum part side of the die. ;CONSTITUTION: A rim part composed of a rim of a wheel and a disk joining part succeeded the above internal side are formed as one body by machining an initial material composed of a raw material being enabled with deformation processing. The initial material is pressed with a pair of dies 301, 302 mutually opposing, a projecting part of raw material which projects from a circumferential edge boundary part of these dies due to the expanding elongation of the initial material followed to this pressing is formed with bending to a drum part side of one side die with a relatively rotating roller 401 and the initial material is formed to a dish like body. An outer circumferential part being matching to a bottom part of this dish like body is opened with cutting to an outer rim side and an inner rim side. Each part formed with this cut opening process is formed with roll to a rim section. In the bottom part of the dish like body is made so as to provide, at least, the disk joining part of the rim part.;COPYRIGHT: (C)1994,JPO&Japio
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