Method for manufacturing press-formed product and press-forming apparatus

1. A method of manufacturing a press-formed product by press forming a forming material made of a high-tensile strength steel sheet of 390 MPa or more, the press-formed product extending in a predetermined direction, having a substantially gutter-shaped cross section intersecting the predetermined direction, and including

a gutter bottom,

a ridge connected to the gutter bottom,

a vertical wall connected to the ridge, and

an outward continuous flange being continuously formed along at least the gutter bottom and the ridge in at least one end in the predetermined direction,

the method comprising:

a first step in which,

by using a first press-forming apparatus including a first punch, a first die, a first pad, and a second pad, the both pads facing the first punch,

the first pad presses at least a part of a portion to be formed into the gutter bottom of the forming material to press the forming material against the first punch in a manner that an end of the forming material connected to the portion to be formed into the gutter bottom is raised in a direction opposite to a pressing direction and at least a part of the portion to be formed into the gutter bottom is restrained by the first pad and the first punch, and

the second pad subsequently presses at least a part of an end in the predetermined direction of a portion to be formed into the ridge against the first punch in a manner that the end in the predetermined direction connected to the portion to be formed into the ridge is raised in the direction opposite to the pressing direction and the portion to be formed into the ridge is bent in the pressing direction, and simultaneously, at least the part of the portion to be formed into the ridge is restrained by the second pad and the first punch, and

the first punch and the first die carry out press forming to form an intermediate product while the forming material is restrained by the first pad and the second pad; and

a second step in which,

by using a second press-forming apparatus including a second punch and a second die,

the second punch and the second die press form the intermediate product to form the press formed product.

2. The method for manufacturing the press-formed product according to claim 1 , wherein, in the first step, the second pad presses, against the first punch, a portion of at least ⅓ the length of a perimeter of a cross section in the portion to be formed into the ridge starting from a border between the portion to be formed into the ridge and the portion to be formed into the gutter bottom.

3. The method for manufacturing the press-formed product according to claim 1 , wherein the first pad and the second pad are supported by the first die, and the first pad, the second pad, and the first die consecutively press the forming material in this order while the first die is moved toward the first punch.

4. The method for manufacturing the press-formed product according to claim 1 , wherein the press forming in the first step is bending forming.

5. The method for manufacturing the press-formed product according to claim 1 , wherein the press forming in the first step is deep drawing.

6. The method for manufacturing the press-formed product according to claim 1 , wherein the press-formed product is a formed product in which at least one of a width of the gutter bottom and a height of the vertical wall gradually increases toward the end having the outward continuous flange.

7. A press-forming apparatus used for manufacturing a press-formed product extending in a predetermined direction, having a substantially gutter-shaped cross section intersecting the predetermined direction, and including

a gutter bottom,

a ridge connected to the gutter bottom,

a vertical wall connected to the ridge, and

an outward continuous flange being continuously formed along at least the gutter bottom and the ridge in at least one end in the predetermined direction, the press-forming apparatus comprising:

a punch;

a die; and

a pad facing the punch, the punch and the die carrying out press forming while a forming material made of a high-tensile strength steel sheet of 390 MPa or more is restrained by the pad and the punch,

wherein the pad includes a first pad, and a second pad being different from the first pad,

the first pad presses and restrains at least a part of a portion to be formed into the gutter bottom of the forming material to press the forming material against the punch in a manner that an end of the forming material connected to the portion to be formed into the gutter bottom is raised in a direction opposite to a pressing direction and at least a part of the portion to be formed into the gutter bottom is restrained by the first pad and the first punch,

the second pad presses at least a part of an end of an end in the predetermined direction of a portion to be formed into the ridge against the punch in a manner that the end in the predetermined direction connected to the portion to be formed into the ridge is raised in the direction opposite to the pressing direction and the portion to be formed into the ridge is bent in the pressing direction and at least the part of the portion to be formed into the ridge is simultaneously restrained by the second pad and the punch, and

the second pad restrains at least the part of the portion to be formed into the ridge after the first pad restrains at least the part of the portion to be formed into the gutter bottom.

8. The press-forming apparatus according to claim 7 , wherein the second pad presses a portion of at least ⅓ the length of a perimeter of a cross section in the portion to be formed into the ridge starting from a border between the portion to be formed into the ridge and the portion to be formed into the gutter bottom.

9. The press-forming apparatus according to claim 7 , wherein the first pad and the second pad are supported by the die, and the first pad, the second pad, and the die consecutively press the forming material in this order while the die is moved toward the punch.