| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a burring method that enables burring to be performed without working of a prepared hole, even when the prepared hole can be hardly worked. <P>SOLUTION: In the method for burring a plate-like workpiece, a part of the workpiece W is pushed and inserted into a burring portion-forming recess 19 provided in a female mold 3, by a pressurizing protrusion 35 provided in a male mold 5, so as to form a protrusion on the workpiece W. An end of the protrusion is crushed between an end surface 23F of the pressurizing protrusion 23 and a bottom of the burring portion-forming recess 19 or an end surface 23F of a pressurizing protrusion 23 provided on an ascending/descending body 25 provided in a vertically movable manner in the female mold 3 and inserted into the burring portion-forming recess 19, so as to form a thin-walled portion WA thinner than a tubular portion of the protrusion at the end of the protrusion, and stamping is applied to the thin-walled portion WA at the end. The stamping of the thin-walled portion WA is performed in the state of sandwiching the protrusion between a punching mold and a die or in the state of sandwiching a peripheral portion of the protrusion between the punching mold and the die. <P>COPYRIGHT: (C)2012,JPO&INPIT |
