Manufacturing method for press-formed products

Abstract

To reduce press molding man-hours.SOLUTION: In order to manufacture a press-molded product comprising a tabular part and a wall part, a tabular blank is pinched by a first pinching structure which is positioned on a first side in a plate thickness direction with respect to the blank and a second pinching structure which is positioned on a second side opposite to the first side in the plate thickness direction with respect to the blank. By press molding that is performed moving a first metal mold in a press direction which is parallel to the plate thickness direction and in which the first metal mold relatively approaches the blank, the wall part is formed on the blank. By press molding that is performed by further moving the first metal mold in the press direction, the tabular part having a recess is formed on the blank.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a press-formed product.

Background Art

[0002] There is known a technique for forming an elongation flange on a plate-like blank material by press forming. The elongation flange is a shape formed, for example, by bending the blank material, and refers to a shape in which the ridge line at the bent portion is a concave arc shape with respect to the blank material.

[0003] For example, Patent Document 1 discloses a technique for suppressing wrinkles in a blank material by sandwiching and fixing the blank material between a punch and a pad when forming an elongation flange on the blank material by press forming.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In addition to the elongation flange, consider forming a press-formed product having a recess recessed in the plate thickness direction in a plate-like portion that is a portion on the opposite side of the elongation flange with respect to the ridge line. In the conventional technology as disclosed in Patent Document 1, when simultaneously forming the formation of the elongation flange and the formation of the recess by press forming, in order to form the recess by the punch and the pad that sandwich the blank material, a convex portion protruding in the plate thickness direction needs to be formed on the punch or the pad. For this reason, when the blank material is sandwiched between the punch and the pad, pad lifting occurs in which the gap between the blank material and the punch or the pad becomes more than the plate thickness due to the convex portion.

[0006] When a pad lift occurs in the blank material, and stretch flanges are formed by press molding, wrinkles are likely to form in the blank material, especially if the blank material is made of a material with low material elongation, such as high-tensile steel.

[0007] Therefore, in order to obtain a press-formed product having a stretched flange and a recess, it was necessary to form the recess in a process after the formation of the stretched flange in order to suppress the occurrence of wrinkles during the formation of the stretched flange. Furthermore, it was necessary to prepare a separate mold for forming the recess from the mold used for the stretched flange.

[0008] One aspect of this disclosure is to reduce the man-hours required for press forming. [Means for solving the problem]

[0009] One aspect of the present disclosure is a method for manufacturing a press-formed product comprising a plate-like portion having a recess that is concave in the thickness direction, and a wall portion extending from the end of the plate-like portion in a direction intersecting the plate-like portion. The method for manufacturing a press-formed product comprises clamping a blank material, forming a wall portion on the blank material, and forming a plate-like portion having a recess on the blank material.

[0010] Clamping a blank material involves clamping the blank material with a first clamping structure and a second clamping structure. The first clamping structure is located on the first side in the thickness direction relative to the plate-shaped blank material. The second clamping structure is located on the second side in the thickness direction relative to the blank material, opposite to the first side.

[0011] Forming a wall portion in a blank material involves press forming the blank material, which is clamped by a first clamping structure and a second clamping structure, by moving the first die and at least one of the clamping portion in a pressing direction parallel to the thickness direction and in which the first die approaches the blank material relatively, thereby forming a wall portion in the blank material. The first die is located first to the blank material. The clamping portion is a collection of the first clamping structure, the second clamping structure, and the blank material.

[0012] Forming a plate-like portion having a recess in a blank material involves press forming of a blank material on which a wall portion is formed by further moving at least one of the first and second dies in the pressing direction so that the first and second dies are closer together, thereby forming a plate-like portion having a recess in the blank material. The second die is located on the second side of the blank material.

[0013] With this configuration, by first positioning the first and second molds on the first and second sides of the blank material, respectively, and then moving the object in the same pressing direction, walls and recesses can be formed in the blank material. This reduces the number of steps required for press forming.

[0014] According to one aspect of the present disclosure, forming a wall portion may include forming a wall portion in the blank material by moving the first die in the pressing direction. Forming a plate-like portion may include forming a plate-like portion having a recess in the blank material by further moving the first die in the pressing direction such that a recess is formed in the blank material due to the proximity of the first die and the second die.

[0015] With this configuration, by moving the first die once in the pressing direction, walls and recesses can be formed in the blank material. This reduces the number of steps required for press forming. In one aspect of this disclosure, the plate-like portion may have a first recess and a second recess. The first recess is configured as a recess. The second recess is shallower than the first recess and recessed in the thickness direction of the plate. Clamping the blank material may include forming the second recess in the blank material by clamping the blank material with the first clamping structure and the second clamping structure.

[0016] With this configuration, a second recess, which is shallower than the first recess, can be formed when the blank material is clamped between the first and second clamping structures. This reduces the number of steps required for press forming.

[0017] In one aspect of the present disclosure, sandwiching the blank material may include sandwiching the blank material at at least two points separated in a direction orthogonal to the plate thickness direction by a first sandwiching structure and a second sandwiching structure. The at least two points may include a first point and a second point. Forming the plate-like portion may include forming a recess in the blank material by moving at least one of the first mold and the second mold so as to pass between the first point and the second point.

[0018] According to such a configuration, a recess can be formed between the two points where the blank material is sandwiched by the first sandwiching structure and the second sandwiching structure. In one aspect of the present disclosure, the blank material may be made of a high-tensile material. The high-tensile material may be read as high-tensile steel.

[0019] According to such a configuration, when forming a press-formed product from a blank material made of a high-tensile material, it is possible to suppress the occurrence of cracks or wrinkles in the press-formed product.

Brief Description of the Drawings

[0020] [Figure 1] It is a schematic perspective view of a press-formed product. [Figure 2] It is a schematic perspective view of an upper pad, a blank material, a lower pad, and a lower mold. [Figure 3] It is a cross-sectional view along the press direction of the blank material and its peripheral structure in the sandwiching step. [Figure 4] It is a cross-sectional view along the press direction of the blank material and its peripheral structure in the wall forming step. [Figure 5] It is a cross-sectional view along the press direction of the blank material and its peripheral structure in the top plate portion forming step. [Figure 6] It is an additional cross-sectional view regarding the cross-section along the press direction of the blank material and its peripheral structure in the sandwiching step. [Figure 7] It is an additional cross-sectional view regarding the cross-section along the press direction of the blank material and its peripheral structure in the wall forming step. [Figure 8] An additional cross-sectional view along the pressing direction of the blank material and its peripheral structure in the top plate forming process. [Figure 9] A cross-sectional view along the pressing direction of the blank material and its peripheral structure in the wall forming process of another embodiment. [Figure 10] A cross-sectional view along the pressing direction of the blank material and its peripheral structure in the wall forming process of another embodiment. [Figure 11] A schematic perspective view of a press-formed product in another embodiment where a recess is located at the end of a plate-like portion. [Figure 12] A schematic perspective view of a press-formed product in another embodiment where a recess extends from the first end to the second end of a plate-like portion. [Figure 13] A schematic perspective view of a press-formed product in another embodiment where a recess has a gently convex shape. [Figure 14] A flowchart showing a method for manufacturing a press-formed product. [Figure 15] FIG. 15A is a perspective view of another press-formed product. FIG. 15B is a top view of the press-formed product. FIG. 15C is a side view of the press-formed product. [Embodiments for Carrying out the Invention]

[0021] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings. [1. First Embodiment] The press-formed product 1 shown in FIG. 1 is an exemplary press-formed product 1 for explaining the manufacturing method of the press-formed product according to the first embodiment. The manufacturing method of this embodiment is not limited to the press-formed product 1 shown in FIG. 1 and can be used for manufacturing press-formed products of various shapes. The manufacturing method of this embodiment can be used, for example, for manufacturing any shape of press-formed product having a plate-like portion with a recess recessed in the plate thickness direction and a wall portion extending from the end of the plate-like portion in a direction intersecting the plate-like portion.

[0022] [1-1. Configuration of Press-Formed Product] The press-formed product 1 shown in Figure 1 is formed by press-forming a metal material. The press-formed product 1 is made of high-tensile steel, also known as high-tensile steel. For example, the press-formed product 1 may be made of high-tensile steel with a tensile strength of 980 MPa or more, or it may be made of high-tensile steel with a tensile strength of 1180 MPa or more.

[0023] The press-formed product 1 comprises a top plate portion 2, a wall portion 3, and a bottom plate portion 4. The top plate portion 2 is a plate-like part that, with the exception of a small portion, extends in a flat plane for most of its length. The top plate portion 2 may or may not be curved in the direction of its thickness. Hereinafter, the direction of the thickness of the top plate portion 2 will be referred to as the up-down direction. The direction of thickness is not limited to the up-down direction; it may also be interpreted as the left-right direction or the front-back direction. The terms "up" and "down" in the up-down direction may be interpreted as mutually exclusive.

[0024] The top plate portion 2 has a first upper recess 21a, a first lower recess 21b, a second upper recess 22a, and a second lower recess 22b. The first upper recess 21a is a portion of the top plate 2 that is recessed upward when viewed from below. The first lower recess 21b is a portion of the top plate 2 that is recessed downward when viewed from above. The depths of both the first upper recess 21a and the first lower recess 21b are greater than the thickness of the top plate 2. That is, the upper surface of the top plate 2 in the region corresponding to the first upper recess 21a is located above the upper surface of the top plate 2 in the surrounding region. The lower surface of the top plate 2 in the region corresponding to the first lower recess 21b is located below the lower surface of the top plate 2 in the surrounding region.

[0025] The second upper recess 22a is a portion of the top plate 2 that is recessed on the upper side when viewed from below. The second lower recess 22b is a portion of the top plate 2 that is recessed on the lower side when viewed from above. The depths of both the second upper recess 22a and the second lower recess 22b are smaller than the thickness of the top plate 2. That is, the depths of both the second upper recess 22a and the second lower recess 22b are smaller than the depths of the first upper recess 21a and the first lower recess 21b.

[0026] The positions in which the first upper recess 21a, the first lower recess 21b, the second upper recess 22a, and the second lower recess 22b are provided are not particularly limited as long as they are on the top plate portion 2. The wall portion 3 is a plate-like portion that extends from the end of the top plate portion 2 in a direction intersecting the top plate portion 2. In this embodiment, the wall portion 3 extends substantially downward from the end of the top plate portion 2.

[0027] The portion where the top plate portion 2 and the wall portion 3 are connected forms a ridge line 3a. The ridge line 3a is a concave arc shape that is recessed in a direction parallel to the upper surface of the top plate portion 2. As shown in Figure 1, the wall portion 3 is curved along the ridge line 3a. The wall portion 3 corresponds to the extension flange formed at the end of the top plate portion 2.

[0028] The bottom plate portion 4 is a plate-like portion of the wall portion 3 that extends in a direction intersecting the wall portion 3 from the end opposite to the ridge line 3a. The bottom plate portion 4 extends in the opposite direction to the direction in which the top plate portion 2 extends relative to the wall portion 3. Although not limited, in this embodiment, the bottom plate portion 4 is approximately parallel to the top plate portion 2.

[0029] [1-2. Configuration of the press molding machine] The press-formed product 1 is formed by press-forming a blank material 10 using a press-forming apparatus 5 (see Figures 2 to 8). The blank material 10 is a plate-shaped member. In this embodiment, as an example, the blank material 10 is a high-tensile steel made of metal.

[0030] As shown in Figures 2 to 8, the press molding apparatus 5 comprises an upper mold 61, an upper pad 62, a gas cushion 63, a lower mold 71, a lower pad 72, and a die cushion 73. The upper die 61 is a die for press forming. The upper die 61 has a top surface 61a, an upper contact portion 61b, an upper wall forming portion 61c, an upper bottom plate forming portion 61d, and an upper protrusion 61e.

[0031] The top surface 61a is the surface located below the upper mold 61 and extends in a direction perpendicular to the vertical direction (hereinafter referred to as the horizontal direction). The upper contact portion 61b is a part that protrudes downward from a portion of the top surface 61a.

[0032] The upper wall forming portion 61c is a plate-like portion that extends downward from a position below the upper contact portion 61b and away from the upper contact portion 61b in a horizontal direction. The angle between the virtual plane formed by extending the upper wall forming portion 61c and the top surface 61a is approximately the same as the angle between the top plate portion 2 and the wall portion 3 in the press-formed product 1.

[0033] The upper bottom plate forming portion 61d is a plate-like portion that extends horizontally from the lower end of the upper wall forming portion 61c, away from the upper wall forming portion 61c. As shown in Figures 6 to 8, the upper protrusion 61e is a portion that protrudes downward from a part of the lower side of the top surface 61a. The lower end of the upper protrusion 61e has a shape that protrudes downward for forming the first lower recess 21b in the press-formed product 1.

[0034] The upper pad 62 is a pad for press molding. In this embodiment, the cross-section of the upper pad 62 in the vertical direction is substantially rectangular. The upper pad 62 has, for example, an upper first recess-forming portion 62a, an upper second recess-forming portion 62b, and an upper through hole 62c, as shown in Figures 2 and 3.

[0035] The upper first recess-forming portion 62a is formed on the lower surface of the upper pad 62 and is a recessed portion on the upper side. The upper first recess-forming portion 62a has a shape for forming the first upper recess 21a in the press-formed product 1.

[0036] The upper second recess-forming portion 62b is formed on the lower surface of the upper pad 62 and is a portion that is recessed from above or protrudes downward for forming the second upper recess 22a or the second lower recess 22b in the press-formed product 1.

[0037] The upper through-hole 62c is a through-hole in the upper pad 62 that penetrates in the vertical direction. As shown in Figures 3 to 8, the gas cushion 63 is a cushion that utilizes the reaction force of compressed gas. The gas cushion 63 expands and contracts vertically due to pressure.

[0038] The upper surface of the gas cushion 63 abuts against the lower surface of the top surface 61a. The lower surface of the gas cushion 63 abuts against the upper surface of the upper pad 62. The lower surface of the gas cushion 63 is located below the upper contact portion 61b.

[0039] The lower die 71 is a die for press forming. As shown in Figures 2 and 3, for example, the lower die 71 has a bottom surface 71a, a lower contact portion 71b, an upper wall forming portion 71c, a lower bottom plate forming portion 71d, and a lower convex portion 71e.

[0040] The bottom surface 71a is the surface located on the upper side of the lower mold 71 and extends horizontally. The lower contact portion 71b is a part that protrudes upward from a portion of the bottom surface 71a. The upper wall forming portion 71c is a plate-like portion that extends downward from a position above the lower contact portion 71b and away from the lower contact portion 71b in a horizontal direction. In the press forming apparatus 5, the upper wall forming portion 61c and the upper wall forming portion 71c are approximately parallel.

[0041] The lower bottom plate forming portion 71d is a plate-like portion that extends horizontally from the lower end of the upper wall forming portion 71c, away from the upper wall forming portion 71c. The lower protrusion 71e is a portion that protrudes upward from a part of the upper side of the bottom surface 71a. The upper end of the lower protrusion 71e has a shape that protrudes upward in order to form the first upper recess 21a in the press-formed product 1.

[0042] The lower pad 72 is a pad for press molding. In this embodiment, the cross-section of the lower pad 72 in the vertical direction is substantially rectangular. The lower pad 72 has, for example, a lower first recess-forming portion 72a, a lower second recess-forming portion 72b, and a lower through hole 72c, as shown in Figures 2 and 3.

[0043] The lower first recess-forming portion 72a is formed on the upper surface of the lower pad 72 and is a recessed portion on the lower side. The lower first recess-forming portion 72a has a shape for forming the first lower recess 21b in the press-formed product 1.

[0044] The lower second recess-forming portion 72b is formed on the upper surface of the lower pad 72 and is a portion that protrudes upward or is recessed from below for forming the second upper recess 22a or the second lower recess 22b in the press-formed product 1.

[0045] The lower through-hole 72c is a through-hole in the lower pad 72 that penetrates in the vertical direction. The die cushion 73 is a cushion for press molding, as shown in Figures 3 to 8. The die cushion 73 expands and contracts vertically due to pressure. The reaction force of the die cushion 73 is greater than the reaction force of the gas cushion 63.

[0046] The upper surface of the die cushion 73 abuts against the lower surface of the lower pad 72. The lower surface of the die cushion 73 abuts against the upper surface of the bottom surface 71a. The upper surface of the die cushion 73 is positioned above the lower contact portion 71b.

[0047] As shown in Figure 2, the lower pad 72 is positioned above the lower die 71. The blank material 10 is positioned above the lower pad 72. The upper pad 62 is positioned above the blank material 10. Press forming is performed on these positioned members by moving the upper die 61 downwards from above the upper pad 62.

[0048] Press forming is not limited to moving only the upper die 61, but may also be performed by moving at least one of the clamping portions, which is a collection of the upper die 61, the upper pad 62, the lower pad 72, and the blank material 10, in a direction parallel to the vertical direction and in a direction in which the upper die 61 moves relatively closer to the blank material 10 (in other words, the pressing direction).

[0049] The manufacturing method for press-formed product 1, as shown in Figure 14, comprises a clamping step S10, a wall forming step S20, and a top plate forming step S30. The manufacturing method for press-formed product 1 is performed in the order of clamping step S10, wall forming step S20, and top plate forming step S30.

[0050] [1-3. Method for manufacturing a press-formed product having an upwardly recessed recess] A method for manufacturing the press-formed product 1 in a cross-section including the first upper recess 21a and the wall portion 3 will be explained with reference to Figures 3 to 5.

[0051] [1-3-1. Clamping process] As shown in Figure 3, the clamping process S10 is a process of clamping the blank material 10 with an upper pad 62 located above the blank material 10 and a lower pad 72 located below the blank material 10.

[0052] The upper pad 62 abuts against the upper surface of the blank material 10. The lower pad 72 abuts against the lower surface of the blank material 10. The blank material 10 is held between the upper pad 62 and the lower pad 72 from above and below. The upper pad 62, the lower pad 72, and the lower mold 71 are arranged such that the horizontal positions of the upper first recess-forming portion 62a of the upper pad 62, the lower through-hole 72c of the lower pad 72, and the lower convex portion 71e of the lower mold 71 are all substantially the same.

[0053] At this time, the blank material 10 deforms along the upper second recess-forming portion 62b and the lower second recess-forming portion 72b due to pressure from the upper pad 62 and the lower pad 72. As a result, a second upper recess 22a and a second lower recess 22b are formed in the blank material 10. However, even after the second upper recess 22a and the second lower recess 22b are formed in the blank material 10, the blank material 10 can still slide horizontally.

[0054] Hereinafter, the hypothetical plane located on approximately the same plane as the portion of the blank material 10 that is in contact with the upper pad 62 and the lower pad 72 will be referred to as the reference plane A (see Figures 4 and 5). [1-3-2. Wall forming process] As shown in Figure 4, the wall formation step S20 is a step in which a wall 3 is formed on the blank material 10, which is sandwiched between the upper pad 62 and the lower pad 72, by pressing the upper die 61 downward.

[0055] In the upper die 61, the upper bottom plate forming section 61d moves toward the surface on the upper surface of the blank material 10 that is not in contact with the blank material 10, which was clamped in the clamping process S10, thereby performing press forming.

[0056] The portion of the blank material 10 that abuts the upper bottom plate forming portion 61d deforms to be located below the reference plane A due to the pressure from the upper bottom plate forming portion 61d. At this time, the blank material 10 bends downward from the end of the portion that is sandwiched between the upper pad 62 and the lower pad 72. This forms a ridge line 3a on the blank material 10. Subsequently, the blank material 10 deforms to abut along the upper wall forming portion 61c. This forms a wall portion 3 on the blank material 10.

[0057] In the wall forming process S20, the upper mold 61 moves downward until the upper contact portion 61b contacts the upper surface of the upper pad 62. At this time, the upper end of the upper wall forming portion 61c does not move below the reference plane A. The blank material 10 and the upper first recess forming portion 62a are separated. The lower convex portion 71e is located below the reference plane A.

[0058] The reaction force of the gas cushion 63 is smaller than the reaction force of the die cushion 73. Therefore, in the wall forming process S20, the gas cushion 63 is compressed downward by the top surface 61a and the upper pad 62 due to the movement of the upper mold 61. The die cushion 73 receives downward pressure from the lower pad 72, but does not deform substantially.

[0059] [1-3-3. Top plate forming process] As shown in Figure 5, the top plate forming step S30 is a step in which press molding is performed on the blank material 10 on which the wall portion 3 has been formed by further moving the upper die 61 downward, thereby forming a top plate portion 2 having a first upper recess 21a on the blank material 10.

[0060] In the top plate forming process S30, the upper mold 61 continues to move downward from the wall forming process S20. At this time, the upper mold 61 moves downward while in contact with the upper pad 62 at the upper contact portion 61b and in contact with the gas cushion 63 at the top surface 61a. Therefore, the upper mold 61, upper pad 62, and gas cushion 63 move downward as a single unit. The following explanation of the top plate forming process S30 will focus on the movement of the upper pad 62. The downward movement of the upper pad 62 means that the upper mold 61 and gas cushion 63 move downward by the same amount as the upper pad 62.

[0061] The lower protrusion 71e in the lower mold 71 is located inside the lower through hole 72c in the lower pad 72. The lower protrusion 71e and the upper first recess forming portion 62a in the upper pad 62 are in substantially the same position in the horizontal direction.

[0062] The portion of the blank material 10 that is in contact with the upper pad 62 and the lower pad 72 moves downward along with the lower pad 72 when pushed downward from the upper pad 62.

[0063] In the blank material 10, the portion located at the same position as both the upper first recess-forming portion 62a and the lower through-hole 72c in the horizontal direction moves downward following the upper pad 62 and contacts the upper end of the lower convex portion 71e. As the upper pad 62 moves further downward, the lower pad 72 moves in accordance with the upper pad 62, and the lower pad 72 moves downward relative to the lower convex portion 71e. As the lower pad 72 moves downward relative to the lower convex portion 71e, the lower convex portion 71e penetrates the lower through-hole 72c and contacts the blank material 10. The portion of the blank material 10 that contacts the lower convex portion 71e receives upward pressure from the lower convex portion 71e and deforms so as to be recessed above the reference surface A. As the upper pad 62 moves further downward, the portion of the blank material 10 that is in contact with the lower protrusion 71e comes into contact with the upper first recess-forming portion 62a of the upper pad 62, and then deforms to come into contact with the outer surface of the upper first recess-forming portion 62a. As a result, a first upper recess 21a is formed in the blank material 10. In other words, a top plate portion 2 having the first upper recess 21a is formed in the blank material 10.

[0064] In the top plate forming process S30, the upper pad 62 moves downward until the blank material 10 contacts the outer surface of the upper first recess forming portion 62a. At this time, the upper pad 62 may also move downward in the top plate forming process S30 until the lower pad 72 contacts the upper surface of the lower contact portion 71b. The upper pad 62 reaches its bottom dead center due to its downward movement in the top plate forming process S30.

[0065] When the upper pad 62 reaches the bottom dead center, the wall portion 3 formed on the blank material 10 comes into contact with the upper wall forming portion 61c and the upper wall forming portion 71c. On the blank material 10, the portion of the wall portion 3 that extends from the end opposite to the ridge line 3a comes into contact with the upper bottom plate forming portion 61d and the lower bottom plate forming portion 71d. As a result, a bottom plate portion 4 is formed on the blank material 10.

[0066] In the top plate forming process S30, the distance between the top surface 61a that contacts the gas cushion 63 and the upper pad 62 is constant, so the gas cushion 63 does not deform substantially. The die cushion 73 is compressed downward by the lower pad 72 and the bottom surface 71a due to the movement of the lower pad 72.

[0067] As described above, the portion of the press-formed product 1 including the first upper recess 21a and the wall portion 3 is formed. The cross-sectional view of the blank material 10 in Figure 5 corresponds to the VV cross-sectional view of the press-formed product 1 in Figure 1.

[0068] [1-4. Method for manufacturing a press-formed product having a recess that is concave downwards] The above describes the manufacturing method of the press-formed product 1, focusing on the VV cross-section of the press-formed product 1 in Figure 1, using Figures 3 to 5. Below, the manufacturing method of the press-formed product 1 will be described, focusing on the VIII-VIII cross-section of the press-formed product 1 in Figure 1, using Figures 6 to 8. Specifically, the manufacturing method of the press-formed product 1 in a cross-section including the first lower recess 21b and the wall portion 3 will be described.

[0069] [1-4-1. Clamping process] In the clamping process S10, as shown in Figure 6, the upper mold 61 and upper pad 62 are positioned on the upper side of the blank material 10, and the lower pad 72 and lower mold 71 are positioned on the lower side of the blank material 10. Of particular note in Figure 6 is the arrangement of the upper convex portion 61e of the upper mold 61, the upper through hole 62c of the upper pad 62, and the lower first recess-forming portion 72a of the lower pad 72 for forming the first lower recess 21b. The upper mold 61, upper pad 62, and lower pad 72 are positioned such that the horizontal positions of the upper convex portion 61e, the upper through hole 62c, and the lower first recess-forming portion 72a are all substantially the same.

[0070] [1-4-2. Wall forming process] In the wall formation process S20, as shown in Figure 7, the upper mold 61 moves downward so that the upper convex portion 61e contacts the upper surface of the blank material 10 during the process until the upper contact portion 61b contacts the upper surface of the upper pad 62.

[0071] When the upper protrusion 61e contacts the upper surface of the blank material 10, the upper contact portion 61b is separated from the upper pad 62. The upper end of the upper wall forming portion 61c has not yet moved below the reference plane A. The upper protrusion 61e is located inside the upper through hole 62c in the upper pad 62. The blank material 10 and the lower first recess forming portion 72a are separated. The lower pad 72 is in contact with the upper surface of the lower contact portion 71b.

[0072] The blank material 10 does not deform until it comes into contact with the upper wall forming portion 61c, and remains separated from the upper wall forming portion 61c. However, the blank material 10 is in contact with the lower end of the upper wall forming portion 61c (in other words, the part where the upper wall forming portion 61c and the upper bottom plate forming portion 61d connect). That is, the blank material 10 is in a state where the wall portion 3 is being formed on the blank material 10.

[0073] [1-4-3. Top plate forming process] As shown in Figure 8, in the top plate forming process S30, the upper die 61 moves further downward on the blank material 10, which is in the process of having the wall portion 3 formed, thereby advancing the press forming process and forming a top plate portion 2 having the first lower recess 21b on the blank material 10.

[0074] In this process, the upper mold 61 continues to move downward from the wall formation process S20. The upper protrusion 61e is located inside the upper through hole 62c in the upper pad 62.

[0075] In this process, the lower pad 72 is in contact with the upper surface of the lower contact portion 71b, thus restricting its downward movement. The portion of the blank material 10 that is in contact with the upper convex portion 61e receives downward pressure from the upper convex portion 61e and deforms so as to be recessed below the reference surface A. Furthermore, as the upper mold 61 moves downward, the portion of the blank material 10 that is in contact with the upper convex portion 61e comes into contact with the lower first recess-forming portion 72a of the lower pad 72 and deforms further so as to come into contact along the lower first recess-forming portion 72a. As a result, a first lower recess 21b is formed in the blank material 10. In other words, a top plate portion 2 having the first lower recess 21b is formed in the blank material 10.

[0076] In this process, the upper die 61 moves downward until the blank material 10 contacts the lower first recess forming portion 72a. At this time, the upper die 61 may also move downward until the upper contact portion 61b contacts the upper pad 62. The upper die 61 may also move downward until the upper end of the upper wall forming portion 61c contacts the blank material 10. The upper die 61 reaches its bottom dead center through downward movement in this process.

[0077] When the upper die 61 reaches the bottom dead center, the portion of the blank material 10 located between the upper wall forming portion 61c and the upper wall forming portion 71c comes into contact with the upper wall forming portion 61c and the upper wall forming portion 71c. This forms a wall portion 3 on the blank material 10. On the blank material 10, the portion of the wall portion 3 that extends from the end opposite to the ridge line 3a comes into contact with the upper bottom plate forming portion 61d and the lower bottom plate forming portion 71d. This forms a bottom plate portion 4 on the blank material 10.

[0078] In this process, the gas cushion 63 is compressed downward by the top surface 61a and the upper pad 62 due to the movement of the upper mold 61. Since the distance between the bottom surface 71a and the lower pad 72 that contact the die cushion 73 is constant, the die cushion 73 does not deform substantially.

[0079] As described above, a portion of the press-formed product 1 including the first lower recess 21b and the wall portion 3 is formed. The cross-sectional view of the blank material 10 in Figure 8 corresponds to the cross-sectional view VIII-VIII of the press-formed product 1 in Figure 1.

[0080] [1-5. Actions and Effects] According to the embodiments described in detail above, the following actions and effects can be obtained. (1a) In the wall formation process S20 shown in Figures 4 and 7, the press forming apparatus 5 performs press forming by moving the upper die 61 downward to form the wall 3 on the blank material 10. Subsequently, in the top plate formation process S30 shown in Figures 5 and 8, the press forming apparatus 5 performs press forming by moving the upper die 61 further downward to form the first upper recess 21a and the first lower recess 21b on the blank material 10. In the top plate formation process S30, the upper die 61 continues to move downward from the wall formation process S20.

[0081] With this configuration, the upper die 61 moves downward only once in total through the wall formation process S20 and the top plate formation process S30. Therefore, the wall 3, the first upper recess 21a, and the first lower recess 21b can be formed on the blank material 10 in a single press molding process. Consequently, the number of press molding steps can be reduced.

[0082] (1b) The depths of the second upper recess 22a and the second lower recess 22b are both smaller than the depth of the first upper recess 21a and the first lower recess 21b. The second upper recess 22a and the second lower recess 22b are formed in the blank material 10 by pressure from the upper pad 62 and the lower pad 72 during the clamping process S10.

[0083] With this configuration, the relatively shallow second upper recess 22a and second lower recess 22b can be formed when the blank material 10 is clamped between the upper pad 62 and the lower pad 72. This reduces the number of steps required for press forming.

[0084] In addition, since the depths of both the second upper recess 22a and the second lower recess 22b are smaller than the thickness of the top plate 2, it is possible to suppress pad lifting when the second upper recess 22a and the second lower recess 22b are sandwiched between the upper pad 62 and the lower pad 72.

[0085] (1c) The first upper recess 21a and the first lower recess 21b are not held in place by the upper pad 62 and the lower pad 72. With this configuration, the relatively deep first upper recess 21a and first lower recess 21b are less susceptible to pressure from the upper pad 62 and lower pad 72. Therefore, it is possible to suppress the occurrence of wrinkles and cracks in the first upper recess 21a and first lower recess 21b.

[0086] (1d) In the wall forming process S20, the blank material 10 is held between the upper pad 62 and the lower pad 72. With this configuration, when the blank material 10 bends downward during the wall formation process S20, it is possible to suppress the occurrence of wrinkles in the blank material 10.

[0087] (1e) Even after the second upper recess 22a and the second lower recess 22b are formed in the blank material 10 during the clamping process S10, the blank material 10 remains slidable in the horizontal direction. In the wall forming process S20, neither the first upper recess 21a nor the first lower recess 21b is formed in the blank material 10.

[0088] With this configuration, when the blank material 10 bends downward during the wall formation process S20, the blank material 10 slides, causing material to flow into the bent portion of the blank material 10. Therefore, it is possible to suppress the occurrence of cracks in the blank material 10 during the wall formation process S20.

[0089] [1-6. Correspondence between terms] In the above embodiment, the top plate portion 2 corresponds to an example of a plate-like portion, the upper side corresponds to an example of a first side in the plate thickness direction, and the lower side corresponds to an example of a second side in the plate thickness direction.

[0090] The upper pad 62 corresponds to an example of the first clamping structure, the lower pad 72 corresponds to an example of the second clamping structure, the upper mold 61 corresponds to an example of the first mold, and the lower mold 71 corresponds to an example of the second mold. The first upper recess 21a and the first lower recess 21b correspond to a recess and an example of the first recess, while the second upper recess 22a and the second lower recess 22b correspond to an example of the second recess.

[0091] In the portion of the upper pad 62 adjacent to the upper through hole 62c, two points located on opposite sides of the upper through hole 62c in the radial direction of the upper through hole 62c correspond to an example of the first and second points.

[0092] In the portion of the lower pad 72 adjacent to the lower through hole 72c, two points located on opposite sides of the lower through hole 72c in the radial direction of the lower through hole 72c correspond to an example of the first and second points.

[0093] The clamping process S10 corresponds to an example of clamping a blank material, the wall forming process S20 corresponds to an example of forming a wall on the blank material, and the top plate forming process S30 corresponds to an example of forming a plate-like portion having a recess on the blank material.

[0094] [2. Other Embodiments] While embodiments of this disclosure have been described above, it goes without saying that this disclosure is not limited to the embodiments described above and can take various forms.

[0095] (2a) In the above embodiment, the first upper recess 21a is formed by press forming in contact with the upper first recess forming portion 62a of the upper pad 62. However, the structure in which the first upper recess 21a is formed is not limited to the upper first recess forming portion 62a. For example, as shown in Figure 9, the press forming apparatus 105 may include, instead of the upper mold 61 and upper pad 62, an upper mold 161 having an upper recess 161f and an upper pad 162 having an upper through hole 162c.

[0096] The upper recess 161f is a portion that protrudes downward from a part of the lower side of the top surface 61a. The lower end of the upper recess 161f has an upward recessed shape for forming the first upper recess 21a in the press-formed product 1.

[0097] The upper through-hole 162c is a through-hole in the upper pad 162 that penetrates in the vertical direction. In this case, during the top plate forming process S30, the upper recess 161f is located inside the upper through hole 162c. The upper recess 161f is positioned in place of the upper first recess forming portion 62a. As the upper mold 161 moves downward, the portion of the blank material 10 that is in contact with the lower convex portion 71e receives upward pressure from the lower convex portion 71e, deforms to recess above the reference surface A, comes into contact with the upper recess 161f, and further deforms to come into contact along the upper recess 161f. As a result, the first upper recess 21a is formed in the blank material 10.

[0098] (2b) In the above embodiment, the first lower recess 21b is formed by press forming in contact with the lower first recess forming portion 72a of the lower pad 72. However, the structure in which the first lower recess 21b is formed is not limited to the lower first recess forming portion 72a. For example, as shown in Figure 10, the press forming apparatus 205 may be equipped with a lower die 271 having a lower top surface 271a and a lower recess 271f instead of the lower die 71 and the lower pad 72.

[0099] The lower top surface 271a is a surface located above the lower mold 271 and extends horizontally. The lower top surface 271a contacts and clamps the lower surface of the blank material 10 during the clamping process S10, the wall forming process S20, and the top plate forming process S30.

[0100] The lower recess 271f is formed on the lower top surface 271a and is a recessed portion on the lower side. The lower recess 271f has a shape for forming the first lower recess 21b in the press-formed product 1.

[0101] In this case, during the top plate forming process S30, the portion of the blank material 10 that comes into contact with the upper convex portion 61e comes into contact with the lower recess 271f instead of the lower first recess forming portion 72a, and further deforms to come into contact along the lower recess 271f. As a result, the first lower recess 21b is formed in the blank material 10.

[0102] In the above embodiment, the lower top surface 271a corresponds to an example of a second clamping structure. (2c) In the above embodiment, the first upper recess 21a is formed in a portion of the top plate portion 2 other than the end. However, the position in which the first upper recess 21a is formed is not limited to this. For example, as shown in Figure 11, in the press-formed product 101, the first upper recess 121a may be formed in the portion of the top plate portion 102 that connects to the wall portion 3. Alternatively, as shown in Figure 12, in the press-formed product 201, the first upper recess 221a may be formed so as to extend from the end of the top plate portion 202 that connects to the wall portion 3 to the end opposite to the wall portion 3.

[0103] (2d) In the above embodiment, the first upper recess 21a and the first lower recess 21b had an angular shape. However, the shapes of the first upper recess 21a and the first lower recess 21b do not have to be angular. For example, as shown in Figure 13, in the press-formed product 301, the first upper recess 321a may be formed in a shape that gently rises on the top plate portion 302. The first upper recess 321a may be a preliminary shape before the angular shape is formed.

[0104] (2e) The manufacturing method of the above embodiment is used for manufacturing an exemplary press-formed product 1. However, the manufacturing method of a press-formed product is not limited to use in manufacturing a press-formed product 1. For example, as shown in Figure 15, it may be used to manufacture a press-formed product 401 having a configuration equivalent to that of press-formed product 1.

[0105] The press-formed product 401 comprises a top plate portion 402, a wall portion 403, and a bottom plate portion 404, which correspond to the top plate portion 2, wall portion 3, and bottom plate portion 4 of the press-formed product 1. The portion where the top plate portion 402 and the wall portion 403 are connected forms a ridge line 403a, which corresponds to the ridge line 3a.

[0106] The top plate portion 402 is curved in the thickness direction. When a press-formed product 401 in which the top plate portion 402 is curved in the thickness direction is formed by a press forming apparatus 5, the surfaces of both the upper pad 62 and the lower pad 72 that contact the blank material 10 are curved in the direction in which the top plate portion 402 is curved.

[0107] The top plate portion 402 has a first upper recess 421a, a first lower recess 421b, a second upper recess 422a, and a second lower recess 422b, which correspond to the first upper recess 21a, the first lower recess 21b, the second upper recess 22a, and the second lower recess 22b.

[0108] The positions in which the first upper recess 421a, the first lower recess 421b, the second upper recess 422a, and the second lower recess 422b are provided are not particularly limited as long as they are on the top plate portion 402. The press-formed product 401 can be used, for example, as a component of the body of a vehicle. The press-formed product 401 may also be used as a component of parts other than the body of a vehicle, or as a component that is not mounted on a vehicle.

[0109] (2f) In the above embodiment, the wall portion 3 has a shape corresponding to an expandable flange. However, the shape of the wall portion 3 is not limited to an expandable flange, and may be a bent flange or a contracted flange, for example.

[0110] (2g) Multiple functions of one component in the above embodiment may be realized by multiple components, or one function of one component may be realized by multiple components. Also, multiple functions of multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Furthermore, some of the configurations of the above embodiment may be omitted. Furthermore, at least some of the configurations of the above embodiment may be added to or replaced with the configurations of other above embodiments.

[0111] [Technical concepts disclosed in this specification] [Item 1] A method for manufacturing a press-formed product comprising a plate-like portion having a recess that is concave in the thickness direction, and a wall portion extending from the end of the plate-like portion in a direction intersecting the plate-like portion, The blank material is clamped by a first clamping structure located on the first side in the thickness direction relative to the plate-shaped blank material, and a second clamping structure located on the second side in the thickness direction relative to the blank material, which is opposite to the first side. Press forming of the blank material clamped by the first clamping structure and the second clamping structure is performed by moving at least one of the first die located on the first side of the blank material, and the clamping portion which is a collection of the first clamping structure, the second clamping structure, and the blank material, in a pressing direction parallel to the thickness direction and in which the first die moves relatively closer to the blank material, thereby forming the wall portion on the blank material. Press forming of the blank material on which the wall portion is formed is performed by further moving at least one of the first mold and the second mold, which is located on the second side of the blank material, in the pressing direction so that the first mold and the second mold are closer together, thereby forming the plate-like portion having the recess in the blank material. including, A method for manufacturing press-formed products.

[0112] [Item 2] A method for manufacturing a press-formed product as described in item 1, Forming the wall portion includes forming the wall portion on the blank material by moving the first mold in the pressing direction, Forming the plate-like portion includes forming the plate-like portion having the recess in the blank material by further moving the first die in the pressing direction such that the recess is formed in the blank material as the first die and the second die approach each other. A method for manufacturing press-formed products.

[0113] [Item 3] A method for manufacturing a press-formed article as described in item 1 or item 2, The plate-like portion has a first recess as the recess, and a second recess that is shallower than the first recess and recessed in the thickness direction of the plate. The clamping of the blank material includes forming the second recess in the blank material by clamping the blank material with the first clamping structure and the second clamping structure. A method for manufacturing press-formed products.

[0114] [Item 4] A method for manufacturing a press-formed article as described in any one of items 1 to 3, The clamping of the blank material includes clamping the blank material at at least two points separated in a direction perpendicular to the thickness direction by the first clamping structure and the second clamping structure, The aforementioned two points include the first point and the second point, Forming the plate-like portion includes forming the recess in the blank material by moving at least one of the first mold and the second mold so as to pass between the first point and the second point. A method for manufacturing press-formed products.

[0115] [Item 5] A method for manufacturing a press-formed article as described in any one of items 1 to 4, The blank material is made of high-tensile steel. A method for manufacturing press-formed products. [Explanation of Symbols]

[0116] 1,101,201,301,401...Press-formed product, 2,102,202,302,402...Top plate section, 3,403...Wall section, 5,105,205...Press forming apparatus, 10...Blank material, 21a,121a,221a,321a,421a...First upper recess, 21b,421b...First lower recess, 61,161...Upper die, 62,162...Upper pad, 71,271...Lower die, 72...Lower pad, S10...Clamping process, S20...Wall section forming process, S30...Top plate section forming process.

Claims

1. A method for manufacturing a press-formed product comprising a plate-like portion having a recess that is concave in the thickness direction, and a wall portion extending from the end of the plate-like portion in a direction intersecting the plate-like portion, The blank material is clamped by a first clamping structure located on the first side in the thickness direction relative to the plate-shaped blank material, and a second clamping structure located on the second side in the thickness direction relative to the blank material, which is opposite to the first side. Press forming of the blank material clamped by the first clamping structure and the second clamping structure is performed by moving at least one of the first die located on the first side of the blank material, and the clamping portion which is a collection of the first clamping structure, the second clamping structure, and the blank material, in a pressing direction parallel to the thickness direction and in which the first die moves relatively closer to the blank material, thereby forming the wall portion on the blank material. Press forming of the blank material having a portion deformed to form the wall portion is performed by further moving at least one of the first mold and the second mold in the pressing direction so that the first mold and the second mold located on the second side of the blank material are closer together, thereby forming the plate-like portion having the recess in the blank material. Includes, When the blank material is held between the first clamping structure and the second clamping structure, a cushion that expands and contracts in the pressing direction due to pressure is located on the second side of the first mold and on the first side of the first clamping structure, and is pressed by the first mold and the first clamping structure. The cushion is compressed parallel to the pressing direction by the first mold and the first clamping structure during the process of forming the wall portion and before the process of forming the plate-like portion. A method for manufacturing press-formed products.

2. A method for manufacturing a press-formed article according to claim 1, Forming the wall portion includes forming the wall portion on the blank material by moving the first mold in the pressing direction, Forming the plate-like portion includes forming the plate-like portion having the recess in the blank material by further moving the first die in the pressing direction such that the recess is formed in the blank material as the first die and the second die approach each other. A method for manufacturing press-formed products.

3. A method for manufacturing a press-formed article according to claim 1, The plate-like portion has a first recess as the recess, and a second recess that is shallower than the first recess and recessed in the thickness direction of the plate. The clamping of the blank material includes forming the second recess in the blank material by clamping the blank material with the first clamping structure and the second clamping structure. A method for manufacturing press-formed products.

4. A method for manufacturing a press-formed article according to claim 1, The clamping of the blank material includes clamping the blank material at at least two points separated in a direction perpendicular to the thickness direction by the first clamping structure and the second clamping structure, The aforementioned two points include the first point and the second point, Forming the plate-like portion includes forming the recess in the blank material by moving at least one of the first mold and the second mold so as to pass between the first point and the second point. A method for manufacturing press-formed products.

5. A method for manufacturing a press-formed article according to claim 1, The blank material is made of high-tensile steel. A method for manufacturing press-formed products.

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