Method of manufacturing press-formed part

Abstract

A method of manufacturing a press-formed part curved in top view and including at least a top portion and a side wall portion continuous from the top portion, the method includes: a forming step of performing press forming by using a forming mold having a first estimated angle, which leaves twist (reverse twist) caused by springback in a direction opposite to twist (forward twist) generated by springback in a case where press forming is performed in one step without giving an estimated angle to a mold; and a restrike step of press-forming a formed part formed in the forming step by using a restrike mold having a second estimated angle.

1 .- 7 . (canceled) 
     
     
         8 . A method of manufacturing a press-formed part curved in top view and including at least a top portion and a side wall portion continuous from the top portion, the method comprising:
 a forming step of performing press forming by using a forming mold having a first estimated angle, which leaves twist (reverse twist) caused by springback in a direction opposite to twist (forward twist) generated by springback in a case where press forming is performed in one step without giving an estimated angle to a mold; and   a restrike step of press-forming a formed part formed in the forming step by using a restrike mold having a second estimated angle.   
     
     
         9 . The method of manufacturing a press-formed part according to  claim 8 , wherein the first estimated angle is larger than a one-step estimated angle at which twist caused by springback in a case where press forming is performed in one step to form the press-formed part has a predetermined threshold or less. 
     
     
         10 . The method of manufacturing a press-formed part according to  claim 9 , wherein a direction of twist caused by springback and the one-step estimated angle are determined by preliminarily performing press-forming analysis and springback analysis of the press-formed part. 
     
     
         11 . The method of manufacturing a press-formed part according to  claim 9 , wherein a direction of twist caused by springback and the one-step estimated angle are determined by preliminarily performing actual press forming of the press-formed part. 
     
     
         12 . The method of manufacturing a press-formed part according to  claim 8 , wherein the first estimated angle or the second estimated angle is defined as an inclination angle of a top portion forming surface portion of a cross section in a width direction at an end of the forming mold or the restrike mold in the longitudinal direction with reference to a top portion forming surface portion of a cross section in a width direction at a center of the forming mold or the restrike mold in the longitudinal direction. 
     
     
         13 . The method of manufacturing a press-formed part according to  claim 9 , wherein the first estimated angle or the second estimated angle is defined as an inclination angle of a top portion forming surface portion of a cross section in a width direction at an end of the forming mold or the restrike mold in the longitudinal direction with reference to a top portion forming surface portion of a cross section in a width direction at a center of the forming mold or the restrike mold in the longitudinal direction. 
     
     
         14 . The method of manufacturing a press-formed part according to  claim 10 , wherein the first estimated angle or the second estimated angle is defined as an inclination angle of a top portion forming surface portion of a cross section in a width direction at an end of the forming mold or the restrike mold in the longitudinal direction with reference to a top portion forming surface portion of a cross section in a width direction at a center of the forming mold or the restrike mold in the longitudinal direction. 
     
     
         15 . The method of manufacturing a press-formed part according to  claim 11 , wherein the first estimated angle or the second estimated angle is defined as an inclination angle of a top portion forming surface portion of a cross section in a width direction at an end of the forming mold or the restrike mold in the longitudinal direction with reference to a top portion forming surface portion of a cross section in a width direction at a center of the forming mold or the restrike mold in the longitudinal direction. 
     
     
         16 . The method of manufacturing a press-formed part according to  claim 8 , wherein an absolute value of the second estimated angle in the restrike step is smaller than an absolute value of the first estimated angle. 
     
     
         17 . The method of manufacturing a press-formed part according to  claim 9 , wherein an absolute value of the second estimated angle in the restrike step is smaller than an absolute value of the first estimated angle. 
     
     
         18 . The method of manufacturing a press-formed part according to  claim 10 , wherein an absolute value of the second estimated angle in the restrike step is smaller than an absolute value of the first estimated angle. 
     
     
         19 . The method of manufacturing a press-formed part according to  claim 11 , wherein an absolute value of the second estimated angle in the restrike step is smaller than an absolute value of the first estimated angle. 
     
     
         20 . The method of manufacturing a press-formed part according to  claim 12 , wherein an absolute value of the second estimated angle in the restrike step is smaller than an absolute value of the first estimated angle. 
     
     
         21 . The method of manufacturing a press-formed part according to  claim 13 , wherein an absolute value of the second estimated angle in the restrike step is smaller than an absolute value of the first estimated angle. 
     
     
         22 . The method of manufacturing a press-formed part according to  claim 14 , wherein an absolute value of the second estimated angle in the restrike step is smaller than an absolute value of the first estimated angle. 
     
     
         23 . The method of manufacturing a press-formed part according to  claim 15 , wherein an absolute value of the second estimated angle in the restrike step is smaller than an absolute value of the first estimated angle.