| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a hydroforming method capable of increasing the sheet thickness of a corner of a hydroformed product while simplifying a device and reducing a production cost, and to provide the hydroformed product. <P>SOLUTION: The hydroforming method, in which a pipe member W containing a liquid is formed into a shape with a corner while making a hydraulic pressure act by pushing the pipe member W with a mobile mold 5b that presses the pipe member W radially inwardly and a pair of right and left cam molds 4 that presses the pipe member W radially inwardly in a different direction from the mobile mold 5b, includes a pre-pressing process in which the pair of right and left cam molds 4 press the pipe member W radially inwardly prior to the pressure operation of the mobile mold 5b; a hydraulic pressure maintaining process in which the hydraulic pressure P in the pipe member W is maintained at a post-contact hydraulic pressure P1 after the pair of right and left cam molds 4 and the mobile 5b come in contact with the pipe member W; and a hydraulic pressure decreasing process in which the hydraulic pressure P in the pipe member W is decreased to a pre-bottom dead center hydraulic pressure P2, that is set lower than the post-contact hydraulic pressure P1, before the cam molds 4 and the mobile mold 5b reach a bottom dead center. <P>COPYRIGHT: (C)2013,JPO&INPIT |
