Press product forming method

Abstract

Provided is a press product forming method for press-forming a curved press product. The curved press product is formed into a hat-like cross-section including an upper surface portion, side wall portions, and flange portions. The press product forming method includes: a pre-forming step of forming, at a widthwise end portion of a flat plate-like blank, at least one bending portion extending along a longitudinal direction; and a main forming step of forming the upper surface portion and the side wall portions under a state in which the bending portion is left.

What is claimed is: 
     
         1 . A press product forming method for press-forming a curved press product,
 the curved press product being formed into a hat-like cross-section including:
 an upper surface portion; 
 side wall portions each bending and extending from a widthwise edge of the upper surface portion in a direction crossing the upper surface portion; and 
 flange portions each bending and extending from an edge of each of the side wall portions, 
 the widthwise edge of the upper surface portion being shaped so as to curve and extend along a longitudinal direction, 
   the press product forming method comprising:   a pre-forming step of forming, at a widthwise end portion of a flat plate-like blank, a highly rigid portion extending along the longitudinal direction; and   a main forming step of forming the upper surface portion and the side wall portions under a state in which the highly rigid portion is left.   
     
     
         2 . A press product forming method according to  claim 1 , wherein the main forming step is carried out by hot press forming. 
     
     
         3 . A press product forming method according to  claim 1 , further comprising a flange-portion flattening step of pressing and flattening the highly rigid portion into one of the flange portions. 
     
     
         4 . A press product forming method according to  claim 3 , wherein the main forming step is carried out by hot press forming. 
     
     
         5 . A press product forming method according to  claim 1 , wherein the highly rigid portion comprises at least one of:
 a ridge which protrudes to at least one of a front surface side and a back surface side of the flat plate-like blank; and   a bending portion which is formed through bending the widthwise end portion of the flat plate-like blank obliquely to at least one of the front surface side and the back surface side of the flat plate-like blank.   
     
     
         6 . A press product forming method according to  claim 5 , wherein the main forming step is carried out by hot press forming. 
     
     
         7 . A press product forming method according to  claim 5 , further comprising a flange-portion flattening step of pressing and flattening the highly rigid portion into one of the flange portions. 
     
     
         8 . A press product forming method according to  claim 7 , wherein the main forming step is carried out by hot press forming. 
     
     
         9 . A press product forming method comprising:
 providing a substantially flat plate-like blank;   pre-forming the blank to create at least one bending portion at or near a widthwise end portion of the blank, the at least one bending portion extending along a longitudinal direction of the blank;   forming the pre-formed blank into a curved press comprising a hat-like cross-section including:   an upper surface portion;   side wall portions each bending and extending from a widthwise edge of the upper surface portion at an angle from the upper surface portion; and   flange portions each bending and extending from an edge of each of the side wall portions,   the widthwise edge of the upper surface portion curving and extending along the longitudinal direction,   wherein the step of forming the pre-formed blank into the curved press is such that the upper surface portion and the side wall portions are formed while the at least one bending portion remains intact.   
     
     
         10 . The method of  claim 9 , wherein the step of forming the pre-formed blank into the curved press comprises hot press forming. 
     
     
         11 . The method of  claim 9 , further comprising pressing and flattening the at least one bending portion into one of the flange portions. 
     
     
         12 . The method of  claim 11 , wherein the step of forming the pre-formed blank into the curved press comprises hot press forming. 
     
     
         13 . The method of  claim 9 , wherein the at least one bending portion comprises at least one of:
 a ridge which protrudes from at least one of a front surface side and a back surface side of the flat plate-like blank; and   a bent flange formed by bending the widthwise end portion of the flat plate-like blank obliquely relative to at least one of the front surface side and the back surface side of the flat plate-like blank.   
     
     
         14 . The method of  claim 13 , wherein the step of forming the pre-formed blank into the curved press comprises hot press forming. 
     
     
         15 . The method of  claim 13 , further comprising pressing and flattening the at least one bending portion into one of the flange portions. 
     
     
         16 . The method of  claim 13 , wherein the ridge is triangular in cross-section. 
     
     
         17 . The method of  claim 9 , wherein the step of pre-forming the blank comprises creating at least two bending portions, with a first bending portion extending along the longitudinal direction of the blank at a first widthwise end portion of the blank and the a second bending portion extending along the longitudinal direction of the blank at a second widthwise end portion of the blank. 
     
     
         18 . The method of  claim 13 , wherein the bent flange extends from the at least one of the front surface side and the back surface side at an angle between approximately 10° and approximately 90°.