Manufacturing process of a press-molded product

Abstract

Manufacturing method of a press-molded product (1), comprising: a plate-shaped section (2) with a recessed portion (21a, 21b) recessed in a first thickness direction of the plate-shaped section (2); and a wall section (3) extending from an edge of the plate-shaped section (2) in a direction intersecting with the plate-shaped section (2), wherein the manufacturing method comprises: clamping a blank (10) with a plate mold by means of and between a first clamping structure (62) and a second clamping structure (72), wherein the first clamping structure (62) is located on a first side in a second thickness direction, which is a thickness direction of the blank (10),wherein the second clamping structure (72) is located on one of the second sides opposite the first side in the second thickness direction with respect to the blank (10) (S10); forming the wall section (3) on the blank (10) by performing compression molding on the blank (10) clamped by means of and between the first clamping structure (62) and the second clamping structure (72), wherein the compression molding is carried out by moving at least one first compression mold (61) located on the first side with respect to the blank (10) and / or a clamping / clamped body (62, 72, 10, 71), which is a collection comprising the first clamping structure (62), the second clamping structure (72), the blank (10) and a second compression mold (71), in a compression direction that runs parallel to the second thickness direction and that allows the first compression mold (61) and the blank (10) to come closer to each other,wherein the second press form (71) is located on the second side with respect to the blank (10) (S20); and forming the plate-shaped section (2) with the recessed part (21a, 21b) on the blank (10) by performing press forming on the blank (10) on which the wall section (3) is being formed, wherein the press forming is carried out by further moving at least the first press form (71) and / or the clamping / clamped body (62, 72, 10, 71) in the pressing direction to allow the first press form (61) and the second press form (71) to come closer to each other (S30), wherein, when the blank (10) is clamped by means of and between the first clamping structure (62) and the second clamping structure (72), a gas cushion (63) which is arranged on the second side with respect to the first press form (61) and on the first side with respect to the first clamping structure (62) contracts or expands under pressure in the pressing direction,while being pressed by the first press mold (61) and the first clamping structure (62), wherein the gas cushion (63) is compressed by the first press mold (61) and the first clamping structure (62) in the pressing direction during the forming of the wall section (3) and before the forming of the plate-shaped section (2).

Description

STATE OF THE ART This disclosure concerns a manufacturing process for a press-molded product. A method for forming an expansion flange on a blank with a plate shape by press forming is known. The expansion flange is achieved, for example, by bending the blank, and a ridge line corresponding to a part where the blank is bent has an arc shape that is recessed in the direction of an unbent part of the blank. The Japanese unexamined patent application, publication JP 2017 - 42 826 A, discloses a method for forming the expansion flange on the blank by means of press molds in order to prevent the occurrence of wrinkling on the blank by clamping and fixing the blank by means of and between a punch and a cushion. From DE 10 2013 002 121 A1, a method for manufacturing body components for a motor vehicle with areas of varying wall thickness is known. This method involves providing a metal strip, which is produced in such a way that wall sections with different wall thicknesses, adapted to the loads of the body components, are created along the length of the metal strip. Sheet metal panels are cut from the metal strip. The metal strip is made of a naturally hard aluminum alloy, and the body component is produced from the sheet metal panels by semi-hot forming in a press tool that is at least partially heated. SUMMARY A case is discussed concerning the forming of a press-molded product which, in addition to the expansion flange, includes a recessed part that is recessed in a plate thickness direction in a plate-shaped section which is a section opposite the expansion flange with respect to the ridge line. In the conventional method, such as that disclosed in the Japanese unexamined patent application, Publication No. 2017-042826, in a case where the expansion flange and the recessed part are formed simultaneously by pressing, the punch or pad must be provided with a projecting portion that extends in the plate thickness direction in order to form the recessed part using the punch and pad clamping the blank between them. When the blank is thus clamped by and between the punch and the pad, the projecting portion creates a gap between the blank and the punch or between the blank and the pad that is greater than or equal to the thickness of the blank. When the expansion flange is formed by press forming with the gap created between the blank and the punch or between the blank and the cushion, the blank tends to wrinkle, especially if the blank is made of a material with lower elasticity, such as a high-strength steel sheet. If the press-molded product is to include the expansion flange and the recessed section, the recessed section must be formed after the expansion flange to prevent wrinkling during the expansion flange formation process. Furthermore, a separate mold for forming the recessed section must be prepared in addition to the mold for the expansion flange. In contrast, the present invention aims to reduce the number of steps in a press forming process. One aspect of the present disclosure for solving this problem is a manufacturing process for a press-molded product according to claim 1, comprising: a plate-shaped section with a recessed portion that is recessed in a first thickness direction of the plate-shaped section; and a wall section extending from an edge of the plate-shaped section in a direction intersecting the plate-shaped section. The manufacturing process for the press-molded product includes: clamping a blank; forming the wall section on the blank; and forming the plate-shaped section with the recessed portion on the blank. Clamping the blank involves clamping it between a first clamping structure and a second clamping structure. The first clamping structure is located on one side in a second thickness direction, which is a thickness direction of the blank with a plate shape. The second clamping structure is located on the opposite side of the blank in the second thickness direction. Forming the wall section of the blank involves shaping the wall section of the blank by performing press forming on the blank, which is clamped by and between the first clamping structure and the second clamping structure. Press forming is performed by moving at least one first press form and / or a clamping / clamped body in a pressing direction. The first press form is located on the first side of the blank with respect to the blank. The clamping / clamped body is a collection comprising the first clamping structure, the second clamping structure, the blank, and a second press form. The second press form is located on the second side of the blank with respect to the blank. The pressing direction is a direction parallel to the second thickness direction, allowing the first press form and the blank to move closer together. When the blank is clamped by means of and between the first clamping structure and the second clamping structure, a gas cushion, which is arranged on the second side with respect to the first die and on the first side with respect to the first clamping structure, contracts or expands under pressure in the pressing direction while it is pressed by the first die and the first clamping structure, the gas cushion being compressed by the first die and the first clamping structure in the pressing direction during the forming of the wall section and before the forming of the plate-shaped section. The forming of the plate-shaped section with the recessed part on the blank comprises forming the plate-shaped section with the recessed part on the blank by performing press forming on the blank on which the wall section is currently being formed, and the press forming is carried out by further moving at least the first press form and / or the clamping / clamped body in the pressing direction, so that it is possible for the first press form and the second press form to come closer to each other. With this design, it is possible to form the wall section and the recessed part of the blank by moving the object in the same pressing direction in a state where the first and second pressing dies are pre-positioned on the blank, respectively, on the first and second sides. This allows for a reduction in the number of steps required for pressing. In one aspect of the present disclosure, forming the wall section on the blank may include forming the wall section by moving the first die in the pressing direction. Forming the plate-shaped section with the recessed part on the blank may include forming the plate-shaped section by further moving the first die in the pressing direction, such that the recessed part on the blank is formed by bringing the first and second dies closer together. With this design, it is possible to form the wall section and the recessed part of the blank with a single movement of the first press die in the pressing direction. This allows for a reduction in the number of steps required for press forming. In one aspect of the present disclosure, the plate-shaped section can comprise a first recessed portion and a second recessed portion. The first recessed portion is shaped as a recessed portion. The second recessed portion is recessed to a shallower depth in the first thickness direction than the first recessed portion. Clamping the blank can involve clamping the blank by means of and between the first clamping structure and the second clamping structure to form the second recessed portion on the blank. With this design, it is possible to form the second recessed section with a shallower recess than the first recessed section if the blank is clamped between the first and second clamping structures. This allows for a reduction in the number of steps required for press forming. In one aspect of the present disclosure, clamping the blank may comprise clamping the blank by means of and between the first clamping structure and the second clamping structure at at least two points spaced apart from each other in a direction perpendicular to the second thickness direction. The at least two points may comprise a first point and a second point. Forming the plate-shaped section may comprise forming the recessed part on the blank by moving at least the first die and / or the second die in such a way that a portion of at least the first die and / or the second die passes between the first point and the second point. With such a design, it is possible to form the recessed part between the two points on the blank clamped between the first clamping structure and the second clamping structure. In one aspect of the present disclosure, the blank can be formed from a high-strength steel sheet. With such a design, it is possible to prevent the occurrence of cracks and wrinkles in the press-formed product if the press-formed product is manufactured from a blank formed from a high-strength steel sheet. BRIEF DESCRIPTION OF THE DRAWINGS Exemplary embodiments of the present disclosure are described below with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of a press-molded product; Fig. 2 is a schematic perspective view of an upper cushion, a blank, a lower cushion, and a lower die; Fig. 3 is a sectional view of the blank and the structures surrounding it along a pressing direction during a clamping step; Fig. 4 is a sectional view of the blank and the structures surrounding it along the pressing direction during a wall section forming step; Fig. 5 is a sectional view of the blank and the structures surrounding it along the pressing direction during a head plate section forming step; Fig. 6 is an additional sectional view of a section of the blank and the structures surrounding it along the pressing direction during the clamping step; Fig.Fig. 7 is an additional sectional view of a section of the blank and the structures around it along the pressing direction during the clamping step; Fig. 8 is an additional sectional view of a section of the blank and the structures around it along the pressing direction during the end plate section forming step; Fig. 9 is a sectional view of the blank and the structures around it along the pressing direction during a wall section forming step in another embodiment; Fig. 10 is a sectional view of the blank and the structures around it along the pressing direction during a wall section forming step in yet another embodiment; Fig. 11 is a schematic perspective view of a press-molded product in which a recessed part lies along an edge of a plate-shaped section in yet another embodiment; Fig.Figure 12 is a schematic perspective view of a press-molded product in which a recessed portion extends from a first end to a second end of a plate-shaped section in yet another embodiment; Figure 13 is a schematic perspective view of a press-molded product in which a recessed portion has a gently raised form in yet another embodiment; Figure 14 is a flowchart showing a manufacturing process for the press-molded products; Figure 15A is a perspective view of another press-molded product; Figure 15B is a top view of the press-molded product in Figure 15A; and Figure 15C is a side view of the press-molded product in Figure 15A. DETAILED DESCRIPTION OF EXAMPLE EXECUTION FORMS The embodiments of this disclosure are not limited to those described below and may take various forms as long as they fall within the technical scope of this disclosure. [1. First embodiment] A press-molded product 1 shown in Fig. 1 is an exemplary press-molded product used to describe a manufacturing process for a press-molded product according to a first embodiment. The manufacturing process in the present embodiment can be used not only to produce the press-molded product 1 shown in Fig. 1, but also to produce press-molded products with various shapes. In the present embodiment, the manufacturing process can be used to produce a press-molded product with any desired shape, comprising, for example, a plate-shaped section with a recessed portion that is recessed in a thickness direction of the plate-shaped section; and a wall section that extends from an edge of the plate-shaped section in a direction intersecting the plate-shaped section. [1-1. Structure of the press-molded product] The press-formed product 1 shown in Fig. 1 is formed by pressing a metallic material. The press-formed product 1 is formed from a high-strength steel sheet. For example, the press-formed product 1 can be formed from a high-strength steel sheet with a tensile strength of 980 MPa or more, or from a high-strength steel sheet with a tensile strength of 1180 MPa or more. The press-molded product 1 has a head plate section 2, a wall section 3 and a bottom plate section 4. Most of the end plate section 2, with the exception of a few parts, lies in the same plane. The end plate section 2 has a plate shape. The end plate section 2 may or may not be curved in one direction of its thickness. Hereinafter, the thickness direction of the end plate section 2 is referred to as an up-down direction. The thickness direction can be read as a right-left direction or a front-to-back direction, without being limited to the up-down direction. "Up" and "down" can be read interchangeably in the context of the up-down direction. The head plate section 2 has a first upwardly recessed part 21a, a first downwardly recessed part 21b, a second upwardly recessed part 22a and a second downwardly recessed part 22b. The first upwardly recessed portion 21a is recessed upwards in the head plate section 2. The first downwardly recessed portion 21b is recessed downwards in the head plate section 2. The depth of the first upwardly recessed portion 21a and the depth of the first downwardly recessed portion 21b are both greater than the thickness of the head plate section 2. That is, in a region corresponding to the first upwardly recessed portion 21a, an upper front surface of the head plate section 2 is located above an upper front surface of the head plate section 2 in a region around the first upwardly recessed portion 21a. In a region corresponding to the first downwardly recessed portion 21b, a lower front surface of the head plate section 2 is located below a lower front surface of the head plate section 2 in a region around the first downwardly recessed portion 21b. The second upwardly recessed portion 22a is recessed upwards in the head plate section 2. The first downwardly recessed portion 22b is recessed downwards in the head plate section 2. The depth of the second upwardly recessed portion 22a and the depth of the second downwardly recessed portion 22b are both less than the thickness of the head plate section 2. That is, the depth of the second upwardly recessed portion 22a and the depth of the second downwardly recessed portion 22b are both less than the depth of the first upwardly recessed portion 21a and the depth of the first downwardly recessed portion 21b. The positions where the first upwardly recessed part 21a, the first downwardly recessed part 21b, the second upwardly recessed part 22a and the second downwardly recessed part 22b are provided are not restricted, especially as long as they are located on the head plate section 2. Wall section 3 extends from an edge of the head plate section 2 in a direction intersecting the head plate section 2. Wall section 3 has a plate shape. In the present embodiment, wall section 3 extends from the edge of the head plate section 2 in a downward direction. A section where the head plate section 2 and the wall section 3 meet forms a ridge line 3a. The ridge line 3a has an arc shape recessed in one direction parallel to the upper front surface of the upper plate section 2. As shown in Fig. 1, the wall section 3 is curved along the ridge line 3a. The wall section 3 corresponds to an expansion flange formed along the edge of the head plate section 2. The base plate section 4 extends from an edge of the wall section 3 opposite the point where the ridge line 3a intersects the wall section 3 in one direction. The base plate section 4 has a plate-like shape. The base plate section 4 extends in a direction opposite to that in which the head plate section 2 extends with respect to the wall section 3. In the present embodiment, the base plate section 4 runs substantially parallel to the head plate section 2, but is not limited to it. [1-1. Design of the press molding device] The press-formed product 1 is formed by applying pressure dies to a blank 10 using a press die 5 (see Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7 to Fig. 8). The blank 10 is a sheet-shaped material. In the present embodiment, the blank 10 is, for example, a high-strength steel sheet made of metal. As shown in Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7 to Fig. 8, the press molding device 5 has an upper press mold 61, an upper cushion 62, a gas cushion 63, a lower press mold 71, a lower cushion 72 and a press mold cushion 73. The upper press mold 61 is a press mold for press forming. The upper press mold 61 has a head front surface 61a, an upper contact part 61b, an upper wall forming part 61c, an upper bottom plate forming part 61d and an upper projecting part 61e. The head front surface 61a is located on the underside of a part of the upper press mold 61. The head front surface 61a extends in a direction perpendicular to the upward-downward direction (hereinafter referred to as the horizontal direction). The upper contact part 61b protrudes downwards from a part of the head front surface 61a. The upper wall forming part 61c is a front surface that extends downwards from a position lower than the upper contact part 61b and is horizontally offset from the upper contact part 61b. The upper wall forming part 61c is curved so that it is convex towards the side on which the upper contact part 61b lies horizontally. An angle formed between an imaginary plane extended from the upper wall forming part 61c and the head front surface 61a is essentially the same as an angle formed between the head plate section 2 and the wall section 3 in the press-molded product 1. The upper base plate forming part 61d is a front surface that extends horizontally from a lower edge of the upper wall forming part 61c such that it moves away from the upper wall forming part 61c. The upper base plate forming part 61d runs substantially parallel to the horizontal direction. As shown in Figs. 6, 7 to 8, the upper contact part 61b projects downwards from a portion of the head front surface 61a. A lower end part of the upper projecting part 61e has a downwardly projecting form for forming the first downwardly recessed part 21b of the press-molded product 1. The upper cushion 62 is a cushion for compression molding. In the present embodiment, a section of the upper cushion 62 has a substantially rectangular shape along the upward-downward direction. As shown in Fig. 2, the upper cushion 62 has an upper first depression forming part 62a, an upper second depression forming part 62b, and an upper through-hole 62c. As shown in Figs. 2 and 3, the upper first depression forming part 62a is formed in a lower front surface of the upper cushion 62. The upper first depression forming part 62a is recessed upwards. The upper first depression forming part 62a has a shape for forming the first upwardly recessed part 21a of the press-molded product 1. As shown in Fig. 2, the upper first depression forming part 62a is formed in the lower front surface of the upper cushion 62. The upper second depression forming part 62b is recessed upwards or projects downwards to form, respectively, the second upwardly recessed part 22a or the second downwardly recessed part 22b of the press-molded product 1. As shown in Fig. 2 and Fig. 6, the upper through-hole 62c penetrates the upper cushion 62 in the upward-downward direction. The gas cushion 63 shown in Figs. 3, 4, 5, 6, 7 to 8 utilizes a reaction force of compressed gas. In response to pressure changes, the gas cushion 63 contracts or expands in the upward-downward direction. An upper front surface of the gas cushion 63 is in contact with the head front surface 61a. A lower front surface of the gas cushion 63 is in contact with an upper front surface of the upper cushion 62. The lower front surface of the gas cushion 63 is located below the upper contact part 61b. The lower press mold 71 is a press mold for compression forming. As shown, for example, in Fig. 2 and Fig. 3, the lower press mold 71 has a bottom front surface 71a, a lower contact part 71b, a lower wall forming part 71c, a lower bottom plate forming part 71d and a lower projecting part 71e. The bottom front surface 71a is located on the top of a part of the lower press mold 71. The bottom front surface 71a extends in a horizontal direction. The lower contact part 71b protrudes upwards from a part of the bottom front surface 71a. The lower wall forming part 71c is a front surface that extends downwards from a position higher than the lower contact part 71b, such that it moves away from the lower contact part 71b in a horizontal direction. The lower wall forming part 71c is curved so that it is convex towards the side on which the lower contact part 71b lies in a horizontal direction. In the press molding device 5, the upper wall forming part 61c and the lower wall forming part 71c run substantially parallel to each other. The lower floor slab forming part 71d extends horizontally away from a lower edge of the lower wall forming part 61c. The lower floor slab forming part 71d has a slab shape. The lower projecting part 71e extends upwards from a portion of the bottom front surface 71a. An upper end portion of the lower projecting part 71e has an upwardly projecting form for forming the first upwardly recessed portion 21a of the press-molded product 1. The lower cushion 72 is a cushion for compression molding. In the present embodiment, a section of the lower cushion 72 has a substantially rectangular shape along the upward-downward direction. As shown in Fig. 2, the lower cushion 72 has a lower first depression forming part 72a, a lower second depression forming part 72b, and a lower through-hole 72c. As shown in Figs. 2 and 6, the lower first depression forming part 72a is formed in an upper front surface of the lower cushion 72. The lower first depression forming part 72a is recessed downwards. The lower first depression forming part 72a has a shape for forming the first downwardly recessed part 21b of the press-molded product 1. As shown in Fig. 2, the lower second depression forming part 72a is formed in the upper front surface of the lower cushion 72. The lower second depression forming part 72b projects upwards or is recessed downwards, so that it forms, respectively, the second upwardly recessed part 22a or the second downwardly recessed part 22b of the press-molded product 1. As shown in Fig. 2 and Fig. 3, the lower through-hole 72c penetrates the lower cushion 72 in the upward-downward direction. As shown in Figs. 3, 4, 5, 6, 7 to 8, the compression mold cushion 73 is a cushion for compression molding. In response to pressure changes, the compression mold cushion 73 contracts or expands in the upward-downward direction. The reaction force of the compression mold cushion 73 is greater than that of the gas cushion 63. An upper front surface of the press-mold pad 73 is in contact with a lower front surface of the lower cushion 72. A lower front surface of the press-mold pad 73 is in contact with the base front surface 71a. The upper front surface of the press-mold pad 73 is located above the lower contact part 71b. As shown in Figures 2 and 3, the lower cushion 72 is arranged above the lower press die 71. The blank 10 is arranged above the lower cushion 72. The upper cushion 62 is arranged above the blank 10. The upper press die 61 is moved downwards from above the upper cushion 62 towards this arrangement to carry out pressing operations. Such press forming is not only carried out by moving the upper press form 61. Such press forming can be carried out by moving at least the upper press form 61 and / or a clamping / clamped body in a pressing direction that runs parallel to the upward-downward direction and that allows the upper press form 61 to come relatively closer to the blank 10. The clamping / clamped body refers to a collection comprising the upper cushion 62, the lower cushion 72, the lower press form 71, and the blank 10. As shown in Fig. 14, the manufacturing process of the press-molded product 1 includes a clamping step S10, a wall section forming step S20 and a head plate section forming step S30, which are carried out in this order. [1-3. Manufacturing process of a press-molded product with an upwardly recessed part] The manufacturing process of the press-molded product 1, which, viewed in a cross-section, comprises the first upwardly recessed part 21a and the wall section 3, is described with reference to Fig. 3, Fig. 4 to Fig. 5. [1-3-1. Clamping step] The clamping step S10 is a step for clamping the blank 10 by means of and between the upper cushion 62 located above the blank 10 and the lower cushion 72 located below the blank 10, as shown in Fig. 3. The upper cushion 62 is in contact with an upper front surface of the blank 10. The lower cushion 72 is in contact with a lower front surface of the blank 10. The blank 10 is clamped by means of and between the upper cushion 62 and the lower cushion 72, respectively, from the top and bottom. The upper cushion 62, the lower cushion 72, and the lower press mold 71 are arranged such that the positions of the upper first recess forming part 62a of the upper cushion 62, the lower through-hole 72c in the lower cushion 72, and the lower projecting part 71e of the lower press mold 71 are essentially the same in the horizontal direction. In this state, the blank 10 receives pressure from the upper cushion 62 and the lower cushion 72, causing it to deform along the upper second depression forming section 62b and the lower second depression forming section 72b, which are shown in Fig. 2. This results in the formation of the second upwardly indented section 22a and the second downwardly indented section 22b on the blank 10. However, the blank 10 remains displaceable in the horizontal direction even after the second upwardly indented section 22a and the second downwardly indented section 22b have been formed on the blank 10. In the following, an imaginary plane positioned essentially on the same plane as a part of the blank 10 in contact with the upper cushion 62 and the lower cushion 72 is referred to as a reference plane A (see Fig. 4 and Fig. 5). [1-3-2. Wall section forming step] The wall section forming step S20 is a step for performing press forming on the blank 10 clamped by means of and between the upper cushion 62 and the lower cushion 72 by moving the upper press form 61 downwards, whereby the wall section 3 is formed on the blank 10 as shown in Fig. 4. The upper base plate forming part 61d of the upper press mold 61 performs the press forming on the blank 10 clamped in the clamping step S10 by moving it in the direction of a part of the upper front surface of the blank 10 that is not in contact with the upper cushion 62. A portion of the blank 10 in contact with the upper base plate forming part 61d receives pressure from the upper base plate forming part 61d, causing it to deform so that it lies below the reference plane A. At this point, the blank 10 is bent downwards at an edge of the part clamped by and between the upper cushion 62 and the lower cushion 72. This results in the formation of the ridge line 3a on the blank 10. Subsequently, the blank 10 is deformed to come into close contact with the upper wall forming part 61c. This results in the formation of the wall section 3 on the blank 10. In the wall section forming step S20, the upper press mold 61 is moved downwards until the upper contact part 61b comes into contact with the upper front surface of the upper cushion 62. At this point, an upper edge of the upper wall forming part 61c is moved so that it is not below the reference plane A. The blank 10 and the upper first recess forming part 62a are spaced apart from each other. The lower projecting part 71e is located below the reference plane A. The reaction force of the gas cushion 63 is smaller than that of the mold cushion 73. Thus, in the wall section forming step S20, the gas cushion 63 is compressed downwards by the head surface 61a and the upper cushion 62 as a result of the downward movement of the upper mold 61. Although the mold cushion 73 receives a downward pressure from the lower cushion 72, the mold cushion 73 is essentially not deformed. [1-3-3. Head plate section forming step] The end plate section forming step S30 is a step for carrying out press forming on the blank 10, on which the wall section 3 is being formed by further moving the upper press form 61 downwards, whereby the end plate section 2 with the first upwardly recessed part 21a is formed on the blank 10, as shown in Fig. 5. In the head plate section forming step S30, the upper press mold 61 continues to move downwards after the wall section forming step S20. At this point, the upper press mold 61 moves downwards while in contact with the upper cushion 62 at the upper contact part 61b and with the gas cushion 63 at the head front surface 61a. Thus, the upper press mold 61, the upper cushion 62, and the gas cushion 63 move downwards as a single unit. The subsequent description of the head plate section forming step S30 focuses on the movement of the upper cushion 62. The downward movement of the upper cushion 62 means that the upper press mold 61 and the gas cushion 63 move downwards by the same distance as the upper cushion 62. The upper end part of the lower projecting part 71e of the lower press mold 71 is located within the lower through-hole 72c in the lower cushion 72. The positions of the lower projecting part 71e and the upper first depression forming part 62a of the upper cushion 62 are essentially the same in the horizontal direction. By pressing the part of the blank 10 in contact with the upper cushion 62 and the lower cushion 72 downwards through the upper cushion 62, it is moved downwards following the upper cushion 62 together with the lower cushion 72. A portion of the blank 10, lying horizontally in the same position as the upper first recess forming part 62a and the lower through-hole 72c, is moved downwards and comes into contact with the upper end portion of the lower projecting part 71e. A further downward movement of the upper cushion 62 causes the lower cushion 72 to move downwards relative to the lower projecting part 71e, following the movement of the upper cushion 62. This downward movement of the lower cushion 72 relative to the lower projecting part 71e causes the upper end portion of the lower projecting part 71e to pass through the lower through-hole 72c and come into contact with the blank 10. A part of the blank 10 that is in contact with the lower projecting part 71e receives an upward pressure from the lower projecting part 71e and is thus deformed so that it is recessed upwards from the reference plane A.Further downward movement of the upper cushion 62 causes an upper front surface of the part of the blank 10 in contact with the lower projecting part 71e to come into contact with the upper first recess forming part 62a of the upper cushion 62 and subsequently to be further deformed so that it comes into close contact with the upper first recess forming part 62a. This results in the formation of the first upwardly recessed part 21a on the blank 10. In other words, the head plate section 2 is formed with the first upwardly recessed part 21a on the blank 10. In the end plate section forming step S30, the upper cushion 62 is moved downwards until the blank 10 comes into close contact with the upper first recess forming part 62a. At this point, the upper cushion 62 can be moved downwards in the end plate section forming step S30 until the lower cushion 72 comes into contact with an upper front surface of the lower contact part 71b. The upper cushion 62 reaches its bottom dead center through its downward movement in the end plate section forming step S30. When the upper cushion 62 reaches its bottom dead center, the wall section 3 formed on the blank 10 is in close contact with the upper wall forming part 61c and the lower wall forming part 71c. A portion of the blank 10 extending from the edge of wall section 3 opposite the ridge line 3a comes into close contact with the upper base plate forming part 61d and the lower base plate forming part 71d. This results in the formation of the base plate section 4 on the blank 10. In the head plate section forming step S30, the distance between the head front surface 61a, which is in contact with the gas cushion 63, and the upper cushion 62 is constant; thus, the gas cushion 63 is essentially not deformed. The press mold cushion 73 is compressed by the lower cushion 72 and the bottom front surface 71a as a result of the downward movement of the lower cushion 72. In this way, a part comprising the first upwardly recessed part 21a and the wall section 3 is formed on the press-molded product 1. A sectional view of the blank 10 in Fig. 5 corresponds to a view of a section of the press-molded product 1 along line VV in Fig. 1. [1-4. Manufacturing process of a press-molded product with a downward-recessed part] Up to this point, the manufacturing process of the press-molded product 1 has been described with reference to Figures 3, 4 to 5, focusing on the section of the press-molded product 1 along line VV in Figure 1. The following description of the manufacturing process of the press-molded product 1 is given with reference to Figures 6, 7 to 8, focusing on a section of the press-molded product 1 along line VIII-VIII in Figure 1. In other words, a description of the manufacturing process of the press-molded product 1, viewed in section, is given, encompassing the first downwardly recessed part 21b and the wall section 3 in the press-molded product 1. [1-4-1. Clamping step] In clamping step S10, as shown in Fig. 6, the upper press die 61 and the upper cushion 62 are arranged above the blank 10, and the lower cushion 72 and the lower press die 71 are arranged below the blank 10. Fig. 6 shows the arrangement of the upper projecting part 61e of the upper press die 61, the upper through-hole 62c in the upper cushion 62, and the lower first recess forming part 72a of the lower cushion 72 for forming the first downwardly recessed part 21b. The upper press die 61, the upper cushion 62, and the lower cushion 72 are arranged such that the positions of the upper projecting part 61e, the upper through-hole 62c, and the lower first recess forming part 72a are essentially the same in the horizontal direction. [1-4-2. Wall section forming step] In the wall section forming step S20 as shown in Fig. 7, the upper press mold 61 is moved downwards until the upper contact part 61b comes into contact with the upper front surface of the upper cushion 62, so that the upper projecting part 61e comes into contact with the upper front surface of the blank 10. When the upper projecting part 61e comes into contact with the upper front surface of the blank 10, the upper contact part 61b is spaced apart from the upper cushion 62. A portion of the upper wall forming part 61c near its upper edge has not yet been moved below the reference plane A. A lower end portion of the upper projecting part 61e is located within the upper through-hole 62c in the upper cushion 62. The blank 10 and the lower first recess forming part 72a are spaced apart from each other. A portion of the lower cushion 72 is in contact with the upper front surface of the lower contact part 71b. A portion of the blank 10 that is in contact with the lower edge of the upper wall forming part 61c (i.e., a portion where the upper wall forming part 61c and the upper bottom plate forming part 61d meet) is deformed so that it is lower than the reference plane A by receiving pressure from the upper wall forming part 61c. In other words, the blank 10 is bent downwards at an edge of the portion clamped by means of and between the upper cushion 62 and the lower cushion 72. At this point, the wall section 3 is being formed on the blank 10. [1-4-3. Head plate section forming step] In the end plate section forming step S30, as shown in Fig. 8, the press forming process on the blank 10, on which the wall 3 is currently being formed, progresses by moving the upper press die 61 further downwards. As a result, the end plate section 2 with the first downwardly recessed part 21b is formed on the blank 10. In this step, the upper press mold 61 is moved continuously downwards after the wall section forming step S20. Part of the upper projecting part 61e is located inside the upper through-hole 62c in the upper cushion 62. In this step, the lower cushion 72 is in contact with the upper front surface of the lower contact part 71b. This restricts the downward movement of the lower cushion 72. A portion of the blank 10 in contact with the upper projecting part 61e receives downward pressure from the upper projecting part 61e and is thus deformed so that it is indented downwards from the reference plane A. Further downward movement of the upper press mold 61 causes a lower front surface of the portion of the blank 10 in contact with the upper projecting part 61e to come into contact with the lower first indentation forming part 72a of the lower cushion 72 and to be further deformed so that it comes into close contact with the lower first indentation forming part 72a. This results in the formation of the first downwardly indented portion 21b on the blank 10.In other words, the head plate section 2 is formed on the blank 10 with the first downwardly recessed part 21b. In this step, the upper press mold 61 is moved downwards until the blank 10 comes into close contact with the lower first recess forming part 72a. At this point, the upper press mold 61 can be moved downwards until the upper contact part 61b comes into contact with the upper cushion 62. The upper press mold 61 can be moved downwards until the upper edge of the upper wall forming part 61c comes into contact with the blank 10. The upper press mold 61 reaches its bottom dead center in this step due to its downward movement. When the upper press die 61 reaches bottom dead center, a portion of the blank 10 located between the upper wall forming part 61c and the lower wall forming part 71c is in close contact with these parts. This results in the formation of wall section 3 on the blank 10. The portion of the blank 10 extending from the lower edge of wall section 3 comes into close contact with the upper base plate forming part 61d and the lower base plate forming part 71d. This results in the formation of base plate section 4 on the blank 10. In this step, the gas cushion 63 is compressed by the head front surface 61a and the upper cushion 62 as a result of the downward movement of the upper press mold 61. Since the distance between the bottom front surface 71a, which is in contact with the press mold cushion 73, and the lower cushion 72 is constant, the press mold cushion 73 is essentially not deformed. In this way, a part comprising the first downwardly recessed part 21b and the wall section 3 is formed in the press-molded product 1. A sectional view of the blank 10 in Fig. 8 corresponds to a view of a section of the press-molded product 1 along line VIII-VIII in Fig. 1. [1-5. Actions and Effects] The embodiment detailed above provides for the actions and effects described below. (1a) In the wall section forming step S20 shown in Figs. 4 and 7, the press molding device 5 passes through the press molds by moving the upper press mold 61 downwards, thereby forming the wall section 3 on the blank 10. Subsequently, in the end plate section forming step S30 shown in Figs. 5 and 8, the press molding device 5 passes through the press molds by moving the upper press mold 61 further downwards, thereby forming the first upwardly recessed part 21a and the first downwardly recessed part 21b on the blank 10. In the end plate section forming step S30, the upper press mold 61 is moved continuously downwards after the wall section forming step S20. In this configuration, the upper press mold 61 is moved downwards only once during the wall section forming step S20 and the end plate section forming step S30. This makes it possible to form the wall section 3, the first upwardly recessed part 21a, and the first downwardly recessed part 21b on the blank 10 with a single press molding operation. This reduces the number of steps required for press molding. (1b) The depths of the second upwardly recessed part 22a and the second downwardly recessed part 22b are smaller than those of the first upwardly recessed part 21a and the first downwardly recessed part 21b. The second upwardly recessed part 22a and the second downwardly recessed part 22b are formed in the blank 10 by receiving pressure from the upper cushion 62 and the lower cushion 72 in the clamping step S10. With this design, it is possible to form the second upwardly recessed part 22a and the second downwardly recessed part 22b, which are relatively flat, when the blank 10 is clamped between the upper cushion 62 and the lower cushion 72. This allows for a reduction in the number of steps required for press forming. The depths of the second upwardly recessed part 22a and the second downwardly recessed part 22b are additionally smaller than the thickness of the head plate section 2. Thus, if the second upwardly recessed part 22a and the second downwardly recessed part 22b are clamped by means of and between the upper cushion 62 and the lower cushion 72, it is possible to prevent the creation of a gap between the blank 10 and the upper cushion 62 and between the blank 10 and the lower cushion 72 that is greater than or equal to the thickness of the blank 10. (1c) The first upwardly recessed part 21a and the first downwardly recessed part 21b are not clamped by means of and between the upper cushion 62 and the lower cushion 72. In this configuration, the first upwardly recessed part 21a and the first downwardly recessed part 21b, which are relatively deep, are less sensitive to pressure from the upper cushion 62 and the lower cushion 72. This makes it possible to prevent the occurrence of wrinkling and cracking in the first upwardly recessed part 21a and the first downwardly recessed part 21b. (1d) In the wall section forming step S20, a part of the blank 10 is clamped by means of and between the upper cushion 62 and the lower cushion 72. In such a design, if the blank 10 is bent downwards in the wall section forming step S20, the occurrence of wrinkling on the blank 10 can be prevented. (1e) Even after the second upwardly recessed part 22a and the second downwardly recessed part 22b were formed on the blank 10 in clamping step S10, the blank 10 is still displaceable in the horizontal direction. In the wall section forming step S20, neither the first upwardly recessed part 21a nor the first downwardly recessed part 21b were formed on the blank 10. In this configuration, the displacement of the blank 10 when it is bent downwards in the wall section forming step S20 causes an inflow of material into the area where the blank 10 is bent. This prevents the formation of cracks in the blank 10 during the wall section forming step S20. [1-6. Correspondence relationships between concepts] In the embodiment described above, the head plate section 2 corresponds to an example of the plate-shaped section, the top corresponds to an example of the first side in the thickness direction, and the bottom corresponds to an example of the second side in the thickness direction. The upper cushion 62 corresponds to an example of the first clamping structure, the lower cushion 72 corresponds to an example of the second clamping structure, the upper press mold 61 corresponds to an example of the first press mold and the lower press mold 71 corresponds to an example of the second press mold. The first upward-recessed part 21a and the first downward-recessed part 21b each correspond to an example of the first recessed part, and the second upward-recessed part 22a and the second downward-recessed part 22b each correspond to an example of the second recessed part. In a part of the upper cushion 62 adjacent to the upper through-hole 62c, two points that lie in a radial direction across the upper through-hole 62c correspond to an example of the first point and an example of the second point. In a part of the lower cushion 72 adjacent to the lower through-hole 72c, two points that lie in a radial direction across the lower through-hole 72c correspond to an example of the first point and an example of the second point. The clamping step S10 corresponds to an example of clamping the blank, the wall section forming step S20 corresponds to an example of forming the wall section on the blank, and the end plate section forming step S30 corresponds to an example of forming the plate-shaped section with the recessed part on the blank. [2. Other embodiments] Although the embodiment of the present disclosure has been described so far, the present disclosure may take various forms without being limited to the embodiment described above. (2a) In the embodiment described above, the first upwardly recessed part 21a is formed by bringing the blank 10 into close contact with the upper first recess forming part 62a of the upper cushion 62 by means of compression molding. However, the structure for forming the first upwardly recessed part 21a is not limited to the upper first recess forming part 62a. For example, a compression molding device 105 shown in Fig. 9 can be used, which comprises an upper compression mold 161 with an upper recessed part 161f instead of the upper compression mold 61 and an upper cushion 162 with an upper through-hole 162c instead of the upper cushion 62. The upper recessed part 161f projects downwards from a portion of the head front surface 61a. A lower end portion of the upper projecting part 161f has an upwardly recessed form for forming the first upwardly recessed part 21a of the press-molded product 1. The upper through-hole 162c penetrates the upper cushion 162 in an upward-downward direction. In the present case, during the head plate section forming step S30, a lower part of the upper recessed section 161f is located within the upper through-hole 162c. The lower end of the upper recessed section 161f is a substitute for the upper first recess forming section 62a. When the upper press mold 161 is moved downwards, a portion of the blank 10 in contact with the lower projecting section 71e receives an upward pressure from the lower projecting section 71e, causing it to deform upwards from the reference plane A, then contact the lower end of the upper recessed section 161f, and then deform further so that it comes into close contact with the lower end of the upper recessed section 161f. This results in the formation of the first upward recessed section 21a on the blank 10. (2b) In the embodiment described above, the first downwardly recessed part 21b is formed by bringing the blank 10 into close contact with the lower first recess forming part 72a of the lower cushion 72 by means of compression molding. However, the structure for forming the first downwardly recessed part 21b is not limited to the lower first recess forming part 72a. For example, a compression molding device 205 shown in Fig. 10 can be used, which comprises a lower compression mold 271 with a lower head front surface 271a and a lower recessed part 271f instead of the lower compression mold 71 and the lower cushion 72. The lower head front surface 271a is located on the top of a part of the lower press mold 271. The lower head front surface 271a extends in a horizontal direction. During the clamping step S10, the wall section forming step S20, and the head plate section forming step S30, the lower head front surface 271a is in contact with the lower front surface of the blank 10 to clamp the blank 10. The lower recessed part 271f is formed in the lower head front surface 271a. The lower recessed part 271f is recessed downwards. The lower recessed part 271f has a form for forming the first downwardly recessed part 21b of the press-molded product 1. In the present case, during the head plate section forming step S30, a lower front surface of the blank 10, comprising the part in contact with the upper projecting part 61e, is in contact with the lower recessed part 271f, which is a replacement for the lower first recessed part 72a, and such a part of the blank 10 is deformed to come into close contact with the lower recessed part 271f. This results in the forming of the first downwardly recessed part 21b on the blank 10. In the embodiment described above, the lower press die 271 corresponds to an example of the second clamping structure. (2c) In the embodiment described above, the first upwardly recessed part 21a is formed in a different position than where the edge of the end plate section 2 is located. However, the position in which the first upwardly recessed part 21a is formed is not limited to this. For example, as in a press-molded product 101 shown in Fig. 11, a first upwardly recessed part 121a can be formed in a portion of an end plate section 102 that extends towards the wall section 3. Alternatively, as in a press-molded product 201 shown in Fig. 12, a first upwardly recessed part 221a can be formed such that it extends from an edge of an end plate section 202 that extends towards the wall section 3 to an edge of the end plate section 202 opposite the wall section 3. (2d) In the embodiment described above, the first upwardly recessed part 21a and the first downwardly recessed part 21b each have an angular shape. However, the shapes of the first upwardly recessed part 21a and the first downwardly recessed part 21b need not be angular. For example, as in a press-molded product 301 shown in Fig. 13, a first upwardly recessed part 321a on a head plate section 302 can be formed such that it has a gently raised shape. The shape of the first upwardly recessed part 321a can be a preliminary shape before it is made angular. (2e) The manufacturing process in the embodiment described above is used to produce the exemplary press-molded product 1. However, the manufacturing process for press-molded products is not limited to being used to produce the press-molded product 1. For example, as shown in Figures 15A, 15B and 15C, the manufacturing process can be used to produce a press-molded product 401 having a configuration equivalent to that of the press-molded product 1. The press-molded product 401 has a head plate section 402, a wall section 403, and a bottom plate section 404 as sections corresponding to the head plate section 2, the wall section 3, and the bottom plate section 4 of the press-molded product 1. A portion where the head plate section 402 and the wall section 403 meet forms a ridge line 403a, corresponding to ridge line 3a. The end plate section 402 is curved in the direction of the thickness. In a case of forming the press-molded product 401, in which the end plate section 402 is curved in the direction of the thickness using the press-mold device 5, the front surfaces of the upper cushion 62 and the lower cushion 72, respectively, which are in contact with the blank 10, are curved along the curvature of the end plate section 402. The head plate section 402 has a first upwardly recessed part 421a, a first downwardly recessed part 421b, a second upwardly recessed part 422a and a second downwardly recessed part 422b as parts corresponding to the first upwardly recessed part 21a, the first downwardly recessed part 21b, the second upwardly recessed part 22a and the second downwardly recessed part 22b. The positions at which the first upwardly recessed part 421a, the first downwardly recessed part 421b, the second upwardly recessed part 422a and the second downwardly recessed part 422b are arranged are not restricted, especially as long as they are located on the head plate section 402. For example, the press-molded product 401 is used as a component forming the body of a vehicle. The press-molded product 401 can be used as a component forming a section of a vehicle other than the body. The press-molded product 401 can be used as a component not mounted in the vehicle. (2f) In the embodiment described above, the wall section 3 has a shape corresponding to an expansion flange. However, the shape of the wall section 3 is not limited to that of an expansion flange. For example, the shape of the wall section 3 may be such that it corresponds to a bent flange or a shrink flange. (2g) In the embodiments described above, functions of a single element can be performed by a plurality of elements, and a single function of a single element can be performed by a plurality of elements. Functions of a plurality of elements can be performed by a single element, and a single function performed by a plurality of elements can be performed by a single element. Part of the design of the embodiments described above can be omitted. At least part of the design of the embodiments described above can be added to or replaced by a design in other embodiments. [Technical ideas revealed herein] [Point 1] A manufacturing method for a press-molded product, comprising: a plate-shaped section with a recessed portion recessed in a first thickness direction of the plate-shaped section; and a wall section extending from an edge of the plate-shaped section in a direction intersecting the plate-shaped section, the manufacturing method comprising: clamping a blank with a plate shape by means of and between a first clamping structure and a second clamping structure, wherein the first clamping structure is located on a first side in a second thickness direction which is a thickness direction of the blank, wherein the second clamping structure is located on a second side opposite the first side in the second thickness direction with respect to the blank;Shaping the wall section on the blank by performing press forming on the blank clamped by means of and between the first clamping structure and the second clamping structure, wherein the press forming is carried out by moving at least one first press form located on the first side with respect to the blank and / or a clamping / clamped body comprising the first clamping structure, the second clamping structure, the blank and a second press form in a pressing direction parallel to the second thickness direction, which allows the first press form to get relatively closer to the blank, wherein the second press form is located on the second side with respect to the blank;and forming the plate-shaped section with the recessed part on the blank by carrying out press forming on the blank on which the wall section is currently being formed, wherein the press forming is carried out by further moving at least the first press form and / or the clamping / clamped body in the pressing direction to allow the first press form and the second press form to come closer together. [Point 2] Manufacturing process of a press-molded product according to point 1, wherein the forming of the wall section on the blank comprises forming the wall section by moving the first press die in the pressing direction, and wherein the forming of the plate-shaped section with the recessed part on the blank comprises forming the plate-shaped section by further moving the first press die in the pressing direction, such that the recessed part on the blank is formed by bringing the first press die and the second press die closer together. [Point 3] Manufacturing method of a press-molded product according to point 1 or 2, wherein the plate-shaped section comprises a first recessed part as the recessed part and a second recessed part which is recessed more shallowly in the first thickness direction than the first recessed part, and wherein the clamping of the blank comprises clamping the blank by means of and between the first clamping structure and the second clamping structure in order to form the second recessed part on the blank. [Point 4] Manufacturing process of a press-molded product according to one of points 1 to 3, wherein clamping the blank comprises clamping the blank by means of and between the first clamping structure and the second clamping structure at at least two points spaced apart from each other in a direction perpendicular to the second thickness direction, wherein the at least two points comprise a first point and a second point, and wherein forming the plate-shaped section comprises forming the recessed part on the blank by moving at least the first press mold and / or the second press mold in such a way that a part of at least the first press mold and / or the second press mold passes between the first point and the second point. [Point 5] Manufacturing process of a press-formed product according to one of points 1 to 4, wherein the press-formed product is formed from a high-strength steel sheet.

Claims

Manufacturing method of a press-molded product (1), comprising: a plate-shaped section (2) with a recessed portion (21a, 21b) recessed in a first thickness direction of the plate-shaped section (2); and a wall section (3) extending from an edge of the plate-shaped section (2) in a direction intersecting with the plate-shaped section (2), wherein the manufacturing method comprises: clamping a blank (10) with a plate mold by means of and between a first clamping structure (62) and a second clamping structure (72), wherein the first clamping structure (62) is located on a first side in a second thickness direction, which is a thickness direction of the blank (10),wherein the second clamping structure (72) is located on one of the second sides opposite the first side in the second thickness direction with respect to the blank (10) (S10); forming the wall section (3) on the blank (10) by performing compression molding on the blank (10) clamped by means of and between the first clamping structure (62) and the second clamping structure (72), wherein the compression molding is carried out by moving at least one first compression mold (61) located on the first side with respect to the blank (10) and / or a clamping / clamped body (62, 72, 10, 71), which is a collection comprising the first clamping structure (62), the second clamping structure (72), the blank (10) and a second compression mold (71), in a compression direction that runs parallel to the second thickness direction and that allows the first compression mold (61) and the blank (10) to come closer to each other,wherein the second press form (71) is located on the second side with respect to the blank (10) (S20); and forming the plate-shaped section (2) with the recessed part (21a, 21b) on the blank (10) by performing press forming on the blank (10) on which the wall section (3) is being formed, wherein the press forming is carried out by further moving at least the first press form (71) and / or the clamping / clamped body (62, 72, 10, 71) in the pressing direction to allow the first press form (61) and the second press form (71) to come closer to each other (S30), wherein, when the blank (10) is clamped by means of and between the first clamping structure (62) and the second clamping structure (72), a gas cushion (63) which is arranged on the second side with respect to the first press form (61) and on the first side with respect to the first clamping structure (62) contracts or expands under pressure in the pressing direction,while being pressed by the first press mold (61) and the first clamping structure (62), wherein the gas cushion (63) is compressed by the first press mold (61) and the first clamping structure (62) in the pressing direction during the forming of the wall section (3) and before the forming of the plate-shaped section (2). Manufacturing method of a press-molded product (1) according to claim 1, wherein forming the wall section (3) on the blank (10) comprises forming the wall section (3) by moving the first press mold (61) in the pressing direction, and wherein forming the plate-shaped section (2) with the recessed part (21a, 21b) on the blank (10) comprises forming the plate-shaped section (2) by further moving the first press mold (61) in the pressing direction, such that the recessed part (21a, 21b) on the blank (10) is formed by bringing the first press mold (61) and the second press mold (71) closer together. Manufacturing method of a press-molded product (1) according to claim 1 or 2, wherein the plate-shaped section (2) comprises a first recessed part (21a, 21b) as the recessed part (21a, 21b) and a second recessed part (22a, 22b) which is recessed more shallowly in the first thickness direction than the first recessed part (21a, 21b), and wherein clamping the blank (10) comprises clamping the blank (10) by means of and between the first clamping structure (62) and the second clamping structure (72) in order to form the second recessed part (22a, 22b) on the blank (10). Manufacturing method of a press-molded product (1) according to claim 1 or 2, wherein clamping the blank (10) comprises clamping the blank (10) by means of and between the first clamping structure (62) and the second clamping structure (72) at at least two points spaced apart from each other in a direction perpendicular to the second thickness direction, wherein the at least two points comprise a first point and a second point, and wherein forming the plate-shaped section (2) comprises forming the recessed part (21a, 21b) on the blank (10) by moving at least the first press mold (61) and / or the second press mold (71) in such a way that a part of at least the first press mold (61) and / or the second press mold (71) passes between the first point and the second point. Manufacturing method of a press-formed product (1) according to claim 1 or 2, wherein the blank (10) is formed from a high-strength steel sheet.

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