Press forming method and press formed part manufacturing method

Abstract

A press forming method of forming a press formed part including: a top portion having a convex peripheral edge having a whole of or part of an outer peripheral edge curved outward in a convex shape; a side wall portion continuous to the top portion via a punch shoulder R portion; and a flange portion continuous to the side wall portion via a die shoulder R portion, the method includes: (a) forming a metal sheet into a preformed part; and (b) forming the preformed part formed in (a) into the press formed part having a target shape, wherein (a) performs forming such that a bending radius of the die shoulder R portion formed corresponding to at least the convex peripheral edge of the top portion of the preformed part is larger than a bending radius of the die shoulder R portion of the press formed part having the target shape.

1 - 4 . (canceled) 
     
     
         5 . A press forming method of forming a press formed part, the press formed part including: a top portion having a convex peripheral edge having a whole of or part of an outer peripheral edge curved outward in a convex shape; a side wall portion continuous to the top portion via a punch shoulder R portion; and a flange portion continuous to the side wall portion via a die shoulder R portion,
 the press forming method comprising:   (a) forming a metal sheet into a preformed part; and   (b) forming the preformed part formed in (a) into the press formed part having a target shape, wherein   (a) performs forming such that a bending radius of the die shoulder R portion formed corresponding to at least the convex peripheral edge of the top portion of the preformed part is larger than a bending radius of the die shoulder R portion of the press formed part having the target shape.   
     
     
         6 . The press forming method according to  claim 5 , wherein
 (a) applies drawing or bending, and   (b) applies bending.   
     
     
         7 . The press forming method according to  claim 5 , wherein the metal sheet is a steel sheet having a tensile strength of 590 MPa or more. 
     
     
         8 . The press forming method according to  claim 6 , wherein the metal sheet is a steel sheet having a tensile strength of 590 MPa or more. 
     
     
         9 . A press formed part manufacturing method of manufacturing a press formed part, the press formed part including: a top portion having a convex peripheral edge having a whole of or part of an outer peripheral edge curved outward in a convex shape; a side wall portion continuous to the top portion via a punch shoulder R portion; and a flange portion continuous to the side wall portion via a die shoulder R portion,
 the method comprising:   (a) forming a metal sheet into a preformed part; and   (b) forming the preformed part formed in (a) into the press formed part having a target shape, wherein   (a) performs forming such that a bending radius of the die shoulder R portion formed corresponding to at least the convex peripheral edge of the top portion of the preformed part is larger than a bending radius of the die shoulder R portion of the press formed part having the target shape.