Method for manufacturing press-formed product

Abstract

A method for manufacturing a press-formed product, the method including press forming a first formed product from a blank material, press forming a second formed product from the first formed product, and press forming the press-formed product from the second formed product. The press-formed product is a member extending in its longitudinal direction, and includes a top plate and two vertical walls. The first formed product includes a preliminary top plate, an inclined section, and a flat section. The second formed product includes a preliminary top plate, an inclined section, and a preliminary vertical wall. The preliminary vertical wall is formed by deforming the flat section while the preliminary top plate and the inclined section in the first formed product are held between dies.

What is claimed is: 
     
         1 . A method for manufacturing a press-formed product, the method comprising:
 forming a first formed product by press forming a plate-shaped blank material;   forming a second formed product by press forming the first formed product; and   forming the press-formed product by press forming the second formed product,   the press-formed product being a member extending in its longitudinal direction, the press-formed product comprising:   a top plate that is an elongated plate-shaped portion extending in the longitudinal direction; and   two vertical walls that are wall-like portions protruding on a first side from opposite ends of the top plate in a width direction of the top plate,   the first formed product being a member extending in the longitudinal direction, the first formed product including:   a preliminary top plate that is an elongated plate-shaped portion extending in the longitudinal direction;   an inclined section that is a plate-shaped portion extending in a curved manner on the first side from a first end of the preliminary top plate in a width direction of the preliminary top plate; and   a flat section that is a plate-shaped portion extending from an end of the inclined section opposite the preliminary top plate,   the second formed product being a member extending in the longitudinal direction, the second formed product including:   the preliminary top plate;   the inclined section; and   a preliminary vertical wall that is a wall-like portion protruding on the first side from the end of the inclined section opposite the preliminary top plate,   the preliminary vertical wall being formed by deforming the flat section while the preliminary top plate and the inclined section in the first formed product are held between dies.   
     
     
         2 . The method according to  claim 1 , wherein
 the first formed product is formed by holding the blank material between a first die disposed on the first side and a second die disposed on a second side opposite the first side, and   the preliminary vertical wall is formed by pressing the flat section from the second side with a third die disposed on the second side while the preliminary top plate and the inclined section in the first formed product are held between the first die and the second die.   
     
     
         3 . The method according to  claim 1 , wherein
 the press-formed product is formed by pressing and deforming the inclined section with a sixth die disposed on the first side while the preliminary top plate in the second formed product is held between a fourth die disposed on a second side opposite the first side and a fifth die disposed on the first side.   
     
     
         4 . The method according to  claim 3 , wherein
 the inclined section and the preliminary vertical wall contact the fourth die and the sixth die when the press-formed product is formed by press forming the second formed product.   
     
     
         5 . The method according to  claim 4 , wherein
 the second formed product includes a flange that is a plate-shaped portion bulging from an end of the preliminary vertical wall opposite the inclined section,   the flange in the second formed product corresponds to part of the flat section in the first formed product,   the flange in the second formed product contacts the fourth die and the sixth die when the press-formed product is formed by press forming the second formed product.   
     
     
         6 . The method according to  claim 1 , wherein
 press forming for forming the first formed product, the second formed product, and the press-formed product is performed by displacing the dies along a first direction,   the press-formed product includes a first top plate end that is located in the width direction of the top plate and corresponds to part of the inclined section in the second formed product,   a distance in the first direction between an end of the preliminary top plate on the inclined section side and an end of the preliminary vertical wall opposite the inclined section, in a first cross section of the second formed product orthogonal to the longitudinal direction, is defined as a first distance,   a distance in the first direction between the first top plate end and an end of one of the two vertical walls protruding from the first top plate end, in a cross section of the press-formed product orthogonal to the longitudinal direction corresponding to the first cross section, is defined as a second distance, and   the first distance and the second distance are approximately same.   
     
     
         7 . The method according to  claim 1 , wherein
 the top plate includes a curved section that is a curved area that bulges out toward the first side in a cross section along the longitudinal direction, and   the second formed product includes the inclined section in part of the press-formed product corresponding to the curved section.   
     
     
         8 . The method according to  claim 1 , wherein
 the press-formed product is made from high-tensile steel having a tensile strength of 980 MPa or more.   
     
     
         9 . The method according to  claim 1 , wherein
 the press-formed product is installed on a vehicle.   
     
     
         10 . The method according to  claim 9 , wherein
 the press-formed product forms part of a vehicle body.