Press molding apparatus and method for manufacturing press molded product

Abstract

To provide a press molding device which can improve robustness of dimensional accuracy of mass-produced articles.SOLUTION: A press molding device 1 manufactures a press molding product 2 with a top plate part 2A and a vertical wall part 2B from a metal plate S. The press molding device comprises: a punch 31 and a pad 41 which constrain a top plate region of the metal plate S; a cam driver 32 with an inclined sliding surface 32A; a bending blade 42 to execute a first molding step where the bending blade contacts with the metal plate S through sliding of the inclined sliding surface 32A to bend the metal plate S at a boundary part between a region to be the vertical wall part 2B of the metal plate S and the top plate region, and a second molding step where the bending blade is moved downward in continuation with the first molding step to sandwich the region to be the vertical wall part 2B between the punch 31 and the bending blade 42 to mold the vertical wall part 2B; and a height adjustment mechanism 33 which changes height of the inclined sliding surface 32A of the cam driver 32 in a vertical direction.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a press-forming device for forming a metal plate into a shape having a top plate portion and a vertical wall portion, and a method for manufacturing a press-formed product. In particular, the present invention relates to a press-forming technology that can improve the robustness of dimensional accuracy in mass production by changing the amount of springback of the vertical wall portion of the formed product. [Background technology]

[0002] Consider press forming a metal sheet into a hat-shaped cross section. In this case, after the die is unloaded, the vertical wall of the formed part may open outward relative to the top plate, resulting in a springback phenomenon known as wall opening. Wall opening changes due to the angle change caused by residual stress in the bent part (ridge part) connecting the top plate and the vertical wall, and the wall warpage caused by bending and unbending deformation of the vertical wall.

[0003] In recent years, the strength of steel sheets used in automotive frame parts has been increasing from the viewpoints of improving collision safety and reducing the weight of the vehicle body. As the strength of steel sheets increases, the residual stress after forming increases, which in turn increases the amount of springback, making it difficult to form the parts with high precision. Furthermore, as the strength of steel sheets increases, the amount of springback varies from product to product during mass production, which raises concerns about the reduced robustness of dimensional accuracy in mass-produced products. As a countermeasure against such springback or against a decrease in the robustness of the dimensional accuracy of mass-produced products, press forming methods equipped with a cam mechanism as described in Patent Documents 1 to 5 have been proposed.

[0004] Patent Document 1 proposes a technique for reducing angle change by applying strong pressure to the bent portion after bending is completed. By using a cam mechanism in the tool for strong pressure processing, the bent portion can be subjected to strong pressure processing from an inclined direction, which further reduces angle change.

[0005] Patent Document 2 proposes a technique for reducing wall warpage by gradually changing the approach angle of the cam bending blade during bending. By optimizing the approach angle, the ironing process on the vertical wall of the workpiece and the associated bending and unbending deformation are avoided, thereby reducing wall warpage.

[0006] Furthermore, Patent Document 3 proposes a technology in which a metal plate is formed into a hat shape using a cam, and then the upper half of the vertical wall portion is clamped and pressed against the lower half to compress the vertical wall portion and reduce wall warping.

[0007] In addition, in Patent Document 4, a slider is provided that can horizontally press the end of an L-shaped workpiece formed in advance into an L-shape using a cam mechanism. A technology is proposed in which the slider is used to adjust the bending angle. The slider is structured so that it can be divided into a portion that contacts a cam driver installed in the upper die and a portion that contacts the end of the workpiece. The length of the slider can be changed by adjusting the distance between them with a shim plate, and the bending angle of the workpiece can be easily adjusted and changed.

[0008] In addition, in Patent Document 5, the lower part of the bending blade that comes into contact with the vertical wall part is provided with a cam mechanism. This proposes a technology that can optimize the clearance for the plate thickness each time, even if the plate thickness of the vertical wall part varies, and can precisely control the bending angle. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent No. 5024212 [Patent Document 2] Patent No. 4746914 [Patent Document 3] JP 2005-254279 A [Patent Document 4] JP 2007-38258 A [Patent Document 5] Japanese Patent Application Publication No. 7-80551 Summary of the Invention [Problem to be solved by the invention]

[0010] Patent Document 1 describes a technique for reducing angle change. Patent Document 2 and Patent Document 3 describe techniques for reducing wall warpage. However, these techniques are techniques for suppressing the amount of springback itself. Furthermore, these techniques cannot intentionally adjust the amount of springback during mass production in order to improve the deterioration of the robustness of dimensional accuracy of mass-produced products caused by the variation in material properties of the processed material.

[0011] Patent Document 4 describes a technique for adjusting the bending angle by changing the length of a slider equipped with a cam mechanism. However, this requires the workpiece to be formed into an L-shape in advance, and two steps are required to adjust the angle.

[0012] Patent Document 5 describes a technique for precisely controlling the bending angle even if the plate thickness varies by using a bending blade equipped with a cam mechanism. However, this is a countermeasure technique that only works when the plate thickness varies, and it is not possible to precisely form the plate if, for example, the strength of the material varies.

[0013] The present invention has been made in view of the above-mentioned points, and has an object to provide a press-forming apparatus and a manufacturing method for press-formed products that can further improve the robustness of the dimensional accuracy of mass-produced products. [Means for solving the problem]

[0014] The inventors discovered that by adjusting the height of the inclined sliding surface provided on the cam driver, the amount of wall warp of the molded product can be intentionally varied, thereby improving the robustness of the dimensional accuracy of mass-produced products.

[0015] The inventor also considered adjusting the horizontal position of the cam driver to adjust the clearance between the bending blade and the vertical wall forming surface of the punch at the bottom dead center. The inventor then considered adjusting the distribution of residual stress in the bent portion of the formed product by adjusting the clearance, thereby intentionally varying the amount of change in angle of the bent portion. The inventor then discovered that this would improve the robustness of the dimensional accuracy of mass-produced products.

[0016] That is, in order to solve the above problems, the inventors have studied the combination of normal pad form molding (second molding) and cam molding (first molding). In normal pad form molding (second molding), the bending blade moves in a vertical direction (press direction) to mold the workpiece. In cam molding (first molding), the bending blade is guided (slid) by a cam driver having an inclined sliding surface, and the bending blade moves in an inclined direction to mold the workpiece. Then, the inventors came up with the idea that the shape of the molded product can be adjusted by adjusting the ratio of normal pad form molding and cam molding in the molding process of the workpiece.

[0017] The inventors have found that in normal pad forming, the vertical wall of the workpiece is subjected to bending and unbending deformation during forming. In contrast, in cam forming, the bending and unbending deformation is small, so that the amount of wall warping is reduced under conditions where the proportion of cam forming is high.

[0018] The inventors also studied cam forming, in which the bending blade slides against a cam driver with an inclined sliding surface to move in an inclined direction to form the workpiece.The inventors then came up with the idea of ​​adjusting the clearance between the bending blade and the punch at the bottom dead center by adjusting the position of the cam driver in the horizontal direction, thereby adjusting the shape of the formed product.

[0019] According to the present invention, since there is no need to form the workpiece into an L-shape in advance, the robustness of the dimensional accuracy of mass-produced products can be improved without increasing the number of processes. Furthermore, the robustness of the dimensional accuracy can be effectively improved with respect to the variations in the material properties of the workpiece other than the plate thickness.

[0020] In order to solve the problem, one aspect of the present invention is a press forming apparatus for manufacturing a press-formed product having a top plate portion and a vertical wall portion continuous in a width direction of the top plate portion from a metal plate, the press forming apparatus including: a top plate forming surface that contacts from below a top plate region that is a region that becomes the top plate portion of the metal plate; a punch having a vertical wall forming surface that forms the vertical wall portion; a pad that presses the top plate region from above; a cam driver that is disposed at a lateral position of the punch opposite to the vertical wall forming surface and has an inclined sliding surface that is inclined so as to approach the punch side as it goes from the upper side to the lower side; and a cam slider surface that slides on the inclined sliding surface, the punch includes a bending blade for performing a first shaping step in which the punch slides along a moving surface to come into contact with the metal plate and bend the metal plate at the boundary between the area that will become the vertical wall portion and the top plate area, and a bending blade for performing a second shaping step in which the punch slides downward after guiding along the inclined sliding surface is completed, to sandwich the area that will become the vertical wall portion between the punch and the bending blade to form the vertical wall portion, and at least one or both of a height adjustment mechanism for changing the vertical position of the inclined sliding surface of the cam driver and an opposing distance adjustment mechanism for adjusting the opposing distance of the cam driver to the vertical wall forming surface.

[0021] Another aspect of the present invention is a manufacturing method of a press-molded product, which manufactures a press-molded product having a top plate portion and a vertical wall portion continuous in a width direction of the top plate portion by press molding a metal plate, comprising: a punch having a top plate molding surface that molds the top plate portion of the metal plate and a vertical wall molding surface that molds the vertical wall portion; a cam driver that is disposed at a lateral position of the punch facing the vertical wall molding surface and has an inclined sliding surface that is inclined so as to approach the punch side as it moves upward and downward; and a bending blade for molding the vertical wall portion that slides on the inclined sliding surface during molding to come into contact with the metal plate and start bending the metal plate at a boundary between an area that becomes the vertical wall portion and an area that becomes the top plate portion in the metal plate; and a top plate region that is the area that becomes the top plate portion of the metal plate is sandwiched and bound by the punch and a pad. The press forming press has a first forming step in which, in a bundled state, the bending blade is guided along the inclined sliding surface, the bending blade is brought into contact with the metal plate, and the metal plate is bent at the boundary between the region that will become the vertical wall portion of the metal plate and the top plate region, and a second forming step in which, after guiding along the inclined sliding surface is completed, the bending blade is moved downward to sandwich the region that will become the vertical wall portion between the punch and the bending blade to form the vertical wall portion.As a step prior to press forming, at least one or both of a first adjustment step in which the height of the inclined sliding surface is adjusted to change the movement path of the bending blade, and a second adjustment step in which the opposing distance of the cam driver to the vertical wall forming surface is adjusted to adjust the clearance between the bending blade and the vertical wall forming surface at the bottom dead center is provided. Effect of the Invention

[0022] According to this aspect of the present invention, the ratio of the first molding (cam molding) to the second molding (normal pad / form molding) is adjusted by adjusting the height and horizontal position of the cam driver. This adjustment makes it possible to adjust the shape of the molded product after demolding. As a result, according to this aspect of the present invention, even in press molding, where the dimensional accuracy and robustness of mass-produced products is low, it is possible to absorb dimensional fluctuations in the molded product and improve the robustness.

[0023] For example, when the height of the inclined sliding surface of the cam driver is changed, the movement path of the bending blade guided by the inclined sliding surface changes, and the distribution of residual stress in the bent part of the molded product changes. This change (adjustment) intentionally changes the amount of change in wall warpage, making it possible to improve the robustness of the dimensional accuracy of mass-produced products.

[0024] In addition, by changing the distance between the punch and the cam driver, the clearance between the bending blade and the punch at the bottom dead center is adjusted. This changes the distribution of residual stress in the bent part of the molded product. This change (adjustment) intentionally changes the amount of angle change in the bent part, making it possible to improve the robustness of the dimensional accuracy of mass-produced products. [Brief description of the drawings]

[0025] [Figure 1] FIG. 2 is a front view showing an example of a metal plate to be processed and a shape of a molded product using the same, where (a) is a schematic diagram showing the shape of the metal plate and (b) is a schematic diagram showing the shape of the molded product. [Diagram 2] FIG. 1 is a schematic diagram illustrating a configuration of a press-molding apparatus according to a first embodiment of the present invention. [Diagram 3] 1A to 1C are diagrams illustrating an example of a configuration of a height adjustment mechanism according to a first embodiment of the present invention. [Figure 4] 13 is a diagram showing a state of cam shaping (first shaping) when the height adjustment amount T is zero. FIG. [Diagram 5] 13 is a diagram showing a state of a second shaping process following a cam shaping process when a height adjustment amount T is zero. FIG. [Figure 6] 13 is a diagram showing a state of cam shaping (first shaping) when a height adjustment amount T is greater than zero. FIG. [Figure 7] 13 is a diagram showing a state of a second shaping process following a cam shaping process when a height adjustment amount T is greater than zero. FIG. [Figure 8] 13 is a diagram showing a state in which the bending blade has moved to the bottom dead center when the height adjustment amount T is greater than zero. FIG. [Figure 9] FIG. 4 is a schematic diagram illustrating the configuration of a press-molding apparatus according to a second embodiment of the present invention. [Figure 10] 13 is a diagram showing a state of cam shaping (first shaping) when the cam driver is retreated by an adjustment amount H. FIG. [Figure 11] 13 is a diagram showing a state in which the second forming following the cam forming is completed and the bending blade has moved to the bottom dead center when the cam driver is retreated by an adjustment amount H. FIG. [Figure 12] FIG. 2 is a diagram showing the shapes and dimensions of a metal plate to be processed and a molded product in the examples. [Figure 13] FIG. 4 is a conceptual diagram illustrating an angle θ in the embodiment. [Figure 14] FIG. 2 is a diagram for explaining an example based on the first embodiment. [Figure 15] FIG. 2 is a diagram for explaining an example based on the first embodiment. [Figure 16] FIG. 2 is a diagram for explaining an example based on the first embodiment. [Figure 17] FIG. 2 is a diagram for explaining an example based on the first embodiment. [Figure 18] FIG. 2 is a diagram for explaining an example based on the first embodiment. [Figure 19] FIG. 11 is a diagram for explaining an example based on the second embodiment. [Figure 20] FIG. 11 is a diagram for explaining an example based on the second embodiment. [Figure 21] FIG. 11 is a diagram for explaining an example based on the second embodiment. [Figure 22] FIG. 13 is a conceptual diagram for explaining the reason why a wall opening occurs. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Next, an embodiment of the present invention will be described with reference to the drawings. In addition, in each drawing for explaining the device, which is referred to in the following description, each contact portion is shown separated and some parts are exaggerated in order to make the drawing easier to see.

[0027] "First embodiment" First, the first embodiment will be described. In this embodiment, a press-molding device is used to press-mold a metal plate (blank material) as a workpiece to produce a press-molded product (also simply called a molded product).

[0028] The press-molded product 2 exemplified in this embodiment is a molded product having a hat-shaped cross section, which is manufactured by press-molding a metal plate S shown in Fig. 1(a). That is, the molded product 2 of this embodiment includes a top plate portion 2A, a vertical wall portion 2B, and a flange portion 2C, as shown in Fig. 1(b). The vertical wall portion 2B is continuous with both sides of the top plate portion 2A in the width direction via a bent portion 2D (ridge portion). The flange portion 2C is continuous with the lower end portion of the vertical wall portion 2B via a second bent portion 2E.

[0029] However, the press-molded product 2 to which the present disclosure is applicable may have a cross-sectional shape that does not have a flange portion 2 C. In addition, the press-molded product 2 to which the present disclosure is applicable may have a part shape having an L-shaped cross section in which the vertical wall portion 2B is provided on only one side in the width direction of the top plate portion 2A. In this embodiment, the region of the metal sheet S to be formed that will become the top plate portion 2A is referred to as a top plate region, and the region that will become the vertical wall portion 2B is referred to as a vertical wall region.

[0030] (Press forming equipment 1) As shown in FIG. 1, a press molding apparatus 1 of this embodiment includes a lower die 3 and an upper die 4 that face each other vertically. The lower die 3 is provided with a punch 31 and left and right cam drivers 32. In this embodiment, a height adjustment mechanism 33 is further provided. The upper die 4 is provided with a pad 41 and a bending blade 42. In Fig. 2, reference numeral 43 denotes a slide rail for suspending the bending blade 42 from the upper die 4. The bending blade 42 is movable laterally relative to the lower die 3 by the slide rail 43. The lateral direction is the direction in which the bending blade 42 approaches or moves away from the punch 31 in a plan view.

[0031] <Punch 31> The punch 31 supports from below the top plate area of ​​the metal sheet S. The punch 31 has a top plate forming surface 31A, a vertical wall forming surface 31B, and a flange forming surface 31C. The top plate forming surface 31A is a surface that is brought into contact with the top plate region of the metal sheet S from below. The vertical wall forming surface 31B is continuous with the top plate forming surface 31A via a shoulder portion 31D. The shoulder portion 31D is a portion that forms the bent portion 2D. The flange forming surface 31C is formed continuous with the lower end portion of the vertical wall forming surface 31B. The forming surface of the punch 31 has a forming surface shape that follows the shape of the press-formed product 2 to be manufactured.

[0032] <Cam driver 32> The cam drivers 32 constitute a cam mechanism. The cam drivers 32 are disposed on the left and right sides of the punch 31, facing the vertical wall forming surface 31B of the punch 31, respectively. The cam driver 32 includes, as a surface on the punch 31 side, an inclined sliding surface 32A and an up-down guide surface 32B that is continuous with the lower end of the inclined sliding surface 32A and extends in the up-down direction (press direction). The inclined sliding surface 32A has an inclined surface shape obtained by obliquely cutting the upper end corner of the cam driver 32 on the punch 31 side. The inclined sliding surface 32A is an inclined surface that is inclined so as to approach the punch 31 side from the top to the bottom. The upper and lower guide surfaces 32B are surfaces that extend vertically along the pressing direction (downward movement direction).

[0033] The inclination angle α of the inclined sliding surface 32A is, for example, in the range of 5 degrees or more and less than 90 degrees, and preferably in the range of 30 degrees or more and 70 degrees or less. Further, the lateral distance between the vertical wall forming surface 31B of the punch 31 and the upper and lower guide surfaces 32B is set to a distance that allows the bending blade 42 to be accommodated therebetween (see FIG. 5, etc.).

[0034] <Height adjustment mechanism 33> The height adjustment mechanism 33 of this embodiment is disposed between the lower mold 3 and the cam driver 32. The height adjustment mechanism 33 is a mechanism that changes (adjusts) the downward position of the cam driver 32 relative to the lower mold 3, thereby displacing the vertical position of the inclined sliding surface 32A of the cam driver 32. However, the height adjustment amount T of the height adjustment mechanism 33 is set under the condition that the bending blade 42 can contact the metal sheet S in the cam forming (first forming) process described later even if the adjustment amount T is changed.

[0035] The height adjustment amount T is preferably set within a range equal to or less than the length W of the vertical wall portion 2B of the molded product 2 (see FIG. 2). The reason is that if the height adjustment amount T is greater than the length W of the vertical wall portion 2B of the formed product 2, there is a risk that the bending blade 42 will not come into contact with the metal sheet S in the cam forming (first forming) process described below.

[0036] The height adjustment mechanism 33 has, for example, a wedge inclined surface 33A and a height adjustment tool (shim plate 33B) as shown in FIG. 3. The wedge inclined surface 33A is a wedge inclined surface formed on a part or the whole of the bottom surface of the cam driver 32. The height adjustment tool is a height adjustment tool inserted between the lower die 3 and the wedge inclined surface 33A. The height adjustment tool 33B is configured to be slidable on the wedge inclined surface along the inclination direction of the wedge inclined surface. Then, the tool 33B is displaced by driving the actuator 33C. That is, the insertion amount (advance and retreat amount) of the height adjustment tool 33B is adjusted to displace the cam driver 32 in the vertical direction. This makes it possible to adjust the height of the inclined sliding surface 32A. In addition, there is a guide portion (not shown) that guides (restricts) the cam driver 32 so that it can move only in the vertical direction.

[0037] The height adjustment mechanism 33 is not limited to the mechanism using the shim plate 33B as described above. The height adjustment mechanism 33 may be configured, for example, by an actuator for lifting and lowering, which is arranged between the lower mold 3 and the cam driver 32 and is made up of a servo motor, a hydraulic cylinder device, or the like. The height adjustment mechanism 33 is preferably a mechanism that can be controlled from the outside. The height adjustment mechanism 33 is preferably a mechanism that can be operated while the continuous press line is in operation or stopped. Here, the initial position of the cam driver 32 may be a position where the height adjustment amount is zero, or may be the center position of the range where the height can be adjusted.

[0038] <Pad 41> The pad 41 is configured to be movable up and down relative to the upper die 4 by a known mechanism. The pad 41 is disposed at a position facing the top plate forming surface 31A of the punch 31. The pad 41 is brought into contact with the metal sheet S from above. That is, the pad 41 is a component that clamps the top plate region of the metal sheet S together with the top plate forming surface 31A of the punch 31 in the plate thickness direction, and restrains the top plate region of the metal sheet S.

[0039] <Bending blade 42> The bending blade 42 is disposed to the side of the pad 41. The bending blade 42 is attached to the lower die 3 by a slide rail 43 in a state in which the bending blade 42 is movable in a direction toward and away from the pad 41 relative to the lower die 3 in a plan view. The bending blade 42 has, on the surface facing the punch 31, a vertical wall forming surface 42C extending vertically, and a flange forming surface 42D that is continuous with the lower end of the vertical wall forming surface 42C via a shoulder portion 42B and faces downward.

[0040] Moreover, the bending blade 42 has, on the lower side distal to the punch 31, a cam slider surface 42A consisting of an inclined surface for a cam mechanism for sliding on the inclined sliding surface 32A of the cam driver 32. In this embodiment, the initial position of the bending blade 42 before starting forming is a position where at least a part of the cam slider surface 42A faces the inclined sliding surface 32A vertically as shown in Fig. 2. The center of gravity of the bending blade 42 is located closer to the punch 31 than the cam slider surface 42A. During press molding, the bending blade 42 moves downward together with the lower die 3 as the lower die 3 moves downward (in the pressing direction).

[0041] At this time, when the cam slider surface 42A overlaps the inclined sliding surface 32A vertically, the bending blade 42 moves obliquely downward while being guided by the inclined sliding surface 32A. The state where the cam slider surface 42A overlaps the inclined sliding surface 32A vertically means that the bending blade 42 and the inclined sliding surface 32A overlap vertically. That is, the bending blade 42 descends and comes into contact with the inclined sliding surface 32A as shown in FIG. 2. When the bending blade 42 comes into contact with the inclined sliding surface 32A, the bending blade 42 is guided by the inclined sliding surface 32A and moves obliquely downward toward the punch 31, approaching the punch 31. Here, the inclination angle of the cam slider surface 42A does not have to be the same angle as the inclination angle α of the inclined sliding surface 32A. However, if the angles of the two are the same, the bending blade 42 can be stably guided obliquely downward by the inclined sliding surface 32A without the posture of the bending blade 42 swinging.

[0042] Next, when the cam slider surface 42A and the inclined sliding surface 32A no longer overlap each other vertically, the bending blade 42 moves in the vertical direction (press direction) along the upper and lower guide surfaces 32B of the cam driver 32 (second forming step).

[0043] <Conditions for molding operation> Here, in this embodiment, the bending blade 42 is set so that the shoulder portion 42B of the bending blade 42 abuts against the upper surface of the metal sheet S while being guided along the inclined sliding surface 32A.

[0044] Further, the distance between the vertical wall forming surface 31B of the pad 41 and the upper and lower guide surfaces 32B of the cam driver 32 is set so that the bending blade 42 can be positioned between the vertical wall forming surface 31B and the upper and lower guide surfaces 32B.

[0045] <Basic operation of press forming device 1> The basic operation of press molding in the press molding apparatus 1 of this embodiment is as follows. That is, in the press forming apparatus 1 of this embodiment, first, the top plate area of ​​the metal sheet S is restrained by the punch 31 and the pad 41 (see FIG. 2). Then, the lower die 3 is moved in the pressing direction (downward) by an actuator (not shown). As the lower die 3 descends, the bending blade 42 also descends.

[0046] The bending blade 42 descends in the same direction as the lower die until it abuts against the inclined sliding surface 32A. When the bending blade 42 abuts against the inclined sliding surface 32A, the moving direction of the bending blade 42 changes. That is, the bending blade 42 moves obliquely downward by being guided by the inclined sliding surface 32A. The shaping at this time is the first shaping step. In this specification, the first shaping is also called cam shaping.

[0047] While the bending blade 42 is moving diagonally downward while being guided by the inclined sliding surface 32A, the shoulder 42B of the bending blade 42 comes into contact with the upper surface of the metal sheet S. Next, as the bending blade 42 moves diagonally downward while being guided by the inclined sliding surface 32A, the vertical wall region of the metal sheet S is pressed downward. As a result, the metal sheet S is bent at the bending portion 2D (the portion where the shoulder 42B of the punch 31 comes into contact) between the top plate region and the vertical wall region.

[0048] Next, when the bending blade 42 finishes guiding on the inclined sliding surface 32A, it moves downward along the vertical guide surface 32B of the cam driver 32 to further bend the metal sheet S at the bending portion 2D, and at the same time, the metal sheet S is sandwiched between the punch 31 and the bending blade 42, thereby forming the vertical wall portion 2B and the flange portion 2C. This step is the second forming step.

[0049] (operation) The operation of the device 1 will now be described with reference to the drawings. 4 and 5 are schematic diagrams of the molding operation under the condition that the height adjustment amount of the cam driver 32 is set to 0. FIG.

[0050] When the height adjustment amount is 0, in the cam forming process, the bending blade 42 moves obliquely downward while being guided by the inclined sliding surface 32A, while bending the metal sheet S at the bending section 2D, as shown in Fig. 4. This process is the cam forming process in which the bending blade 42 moves obliquely downward to bend the metal sheet S.

[0051] Thereafter, as shown in the schematic diagram of the bottom dead point of forming in Fig. 5, the vertical wall portion 2B and the flange portion 2C are formed by sandwiching the metal plate S between the punch 31 and the bending blade 42. In the example shown in Figs. 4 and 5, the metal plate S is bent only in the cam forming process.

[0052] On the other hand, FIGS. 6 to 8 are schematic diagrams of the molding operation when the height adjustment amount of the cam driver 32 is increased by T [mm] with respect to FIGS.

[0053] In this case, the bending blade 42 is guided by the inclined sliding surface 32A and moves in the inclined direction of the inclined sliding surface 32A as shown in Fig. 6 → Fig. 7. Then, the shoulder portion 42B of the bending blade 42 comes into contact with the metal sheet S closer to the bent portion 2D than in Fig. 4 and Fig. 5, and then the bending blade 42 moves in the inclined direction to bend the metal sheet S, which is a cam forming process.

[0054] When the guiding on the inclined sliding surface 32A is completed, as shown in Fig. 7 and Fig. 8, the bending blade 42 moves vertically to bend the metal sheet S to form the vertical wall portion 2B and the flange portion 2C. This forming process is the second forming process. Fig. 8 shows the state at the bottom dead center. This second forming process constitutes a forming process similar to normal pad form forming. It can be seen that the forming amount in the second forming process increases as the height adjustment amount T of the cam driver 32 is relatively increased.

[0055] As described above, the first shaping (cam shaping) is performed by the bending blade 42 being guided by the inclined sliding surface 32A and moving in the inclined direction. The second shaping is performed by the bending blade 42 moving vertically following the cam shaping. This second shaping process is the same as the conventional pad foam shaping process.

[0056] As can be seen from the above operation, the more the height adjustment amount T of the cam driver 32 is reduced, the more the molding amount in the cam molding increases and the molding amount in the second molding decreases. The reduction in the height adjustment amount T of the cam driver 32 is synonymous with the downward displacement of the inclined sliding surface 32A.

[0057] Here, in the cam forming in which the bending blade 42 is guided by the inclined sliding surface 32A and moves in the inclined direction, the vertical wall portion 2B of the metal sheet S to be processed is not easily bent or unbent, so the amount of wall warping is reduced. On the other hand, in the second forming in which the bending blade 42 moves in the vertical direction, the vertical wall portion 2B is bent or unbent, so the amount of wall warping increases.

[0058] Based on this knowledge, in this embodiment, the springback amount of the molded product 2 after demolding is adjusted by adjusting the height adjustment amount T, thereby adjusting the amount of bending and unbending deformation that the vertical wall portion 2B receives. That is, when the springback amount is smaller than the target value, the height adjustment amount T is adjusted to be larger. On the other hand, when the springback amount is larger than the target value, the height adjustment amount T is adjusted to be smaller.

[0059] As a result, in this embodiment, it becomes possible to adjust the shape of the molded product 2, absorb dimensional variations in mass-produced products, and improve the robustness of dimensional accuracy in mass production.

[0060] Here, in the molded product 2 having a hat-shaped cross section, the wall opening occurs due to an angle change of the bent portion 2D and wall warping, as shown in the schematic diagram of Fig. 22. In this embodiment, the shape of the molded product 2 is adjusted mainly by adjusting the wall warping. Note that the method disclosed herein may be combined with other molded product adjustment methods.

[0061] The height adjustment amount T may be adjusted based on the material characteristic value of the metal plate S. For example, the tensile strength of the metal sheet S is used as the material characteristic value. In general, the higher the tensile strength of the metal sheet S, the greater the springback amount tends to be. In view of this, when the tensile strength of the metal sheet S to be processed is high, the height adjustment amount T of the cam driver 32 is adjusted to be lower than when the tensile strength of the metal sheet S to be processed is low.

[0062] As a result, the amount of springback of the formed product 2 is adjusted such that the higher the tensile strength of the metal plate S, the smaller the amount of forming by the second forming is. In this adjustment, the amount of springback of the formed product 2 is adjusted in a feedforward manner.

[0063] Also, a shape measurement may be performed on all or a part of the molded product 2 previously molded, and the height adjustment amount T may be adjusted based on the shape measurement. In other words, the height position of the inclined sliding surface 32A is adjusted based on the amount of wall warpage of the vertical wall portion 2B actually occurring in the molded product 2 previously molded.

[0064] For example, if it is determined that the preceding product has wall warpage exceeding the target value, the height adjustment amount T of the cam driver 32 is adjusted to be lower than the current amount. Also, if it is determined that the preceding product has wall warpage less than the target amount, the height adjustment amount T of the cam driver 32 is adjusted to be higher than the current amount. In this adjustment, the amount of springback of the formed product 2 is adjusted in a feedback manner.

[0065] "Second embodiment" Next, a second embodiment will be described with reference to the drawings. The basic configuration of this embodiment is similar to that of the first embodiment, as shown in Fig. 9. However, this embodiment includes a facing distance adjustment mechanism 50 instead of the height adjustment mechanism 33 of the first embodiment.

[0066] However, the press forming apparatus 1 may have a configuration including the height adjustment mechanism 33 described in the first embodiment, together with the facing distance adjustment mechanism 50. In this case, for example, by arranging a movable mechanism (guide mechanism) portion of the facing distance adjustment mechanism 50 below the height adjustment mechanism 33, it is possible to use the two mechanisms 33 and 50 in combination.

[0067] (Press forming equipment 1) The press forming apparatus 1 of the second embodiment is similar to that of the first embodiment except for the configuration of the facing distance adjustment mechanism 50, and therefore, explanations of the components other than the facing distance adjustment mechanism 50 will be omitted.

[0068] <Opposing distance adjustment mechanism 50> The opposing distance adjustment mechanism 50 is a mechanism for adjusting the opposing distance between the vertical wall forming surface 31B of the punch 31 and the cam driver 32. As shown in FIG. 9, the opposing distance adjustment mechanism 50 of this embodiment includes a slider rail 51 for a cam driver and an actuator 52 for a cam driver.

[0069] The slider rail 51 for the cam driver is provided on the lower die 3. The slider rail 51 for the cam driver is a guide mechanism that enables the cam driver 32 to advance and retreat toward the punch 31 relative to the lower die 3.

[0070] The cam driver actuator 52 is an actuator formed of a hydraulic cylinder or the like, which displaces the cam driver 32 in the extending direction of the cam driver slider rail 51 . The opposing distance between the cam driver 32 and the punch 31 can be adjusted by driving the cam driver actuator 52 .

[0071] The opposing distance adjustment mechanism 50 has the function of adjusting the clearance between the bending blade 42 and the punch 31 at the bottom dead center of forming. In this embodiment, the initial value of the opposing distance of the cam driver 32 is set to the position where the clearance between the bending blade 42 and the punch 31 is narrowest within the adjustable range. However, the initial value is not limited to this.

[0072] In this embodiment, the opposing distance adjustment mechanism 50 adjusts the clearance between the bending blade 42 and the punch 31 by retracting the cam driver 32 based on the position of the initial value of the opposing distance (adjustment amount H=0). The setting of the position of the initial value of the opposing distance (adjustment amount H=0) is not limited to this.

[0073] The adjustment amount H of the opposing distance by the opposing distance adjustment mechanism 50 corresponds to the adjustment amount of the clearance between the bending blade 42 and the punch 31 at the bottom dead center of forming. The position adjustment by the opposing distance adjustment mechanism 50 may be a mechanism that can be controlled externally using an actuator, as described above, and is preferably a mechanism that can be performed while the continuous press line is in operation or stopped.

[0074] (operation) When the adjustment amount H of the cam driver 32 is set to 0 (initial value), the molding operation is the same as the molding operation shown in FIG. 4 and FIG. 5 in the first embodiment.

[0075] 10 and 11 are diagrams showing a forming operation in which the cam driver 32 is set in a direction that widens the clearance between the bending blade 42 and the punch 31 at the bottom dead point of forming. In other words, this condition is an example in which the opposing distance is changed (retracted) by the adjustment amount H.

[0076] In this case, as shown in the schematic diagram of the forming bottom dead center in FIG. 11, the clearance between the bending blade 42 and the punch 31 at the bottom dead center becomes wider as the adjustment amount H increases. Here, the adjustment amount H for the backward direction of the cam driver 32 is set to be positive.

[0077] In the case of forming as in this embodiment, when the clearance between the bending blade 42 and the punch 31 at the bottom dead center is increased, the residual stress is distributed more widely in the bent portion 2D of the formed product 2. As a result, the amount of springback of the angle change in the bent portion 2D becomes larger.

[0078] Therefore, according to this embodiment, the clearance between the bending blade 42 and the punch 31 at the bottom dead center is adjusted by adjusting the opposing distance of the cam driver 32 relative to the punch 31. As a result, the distribution of residual stress in the bent portion 2D of the molded product 2 is adjusted. In turn, the shape of the molded product 2 can be adjusted by adjusting the amount of change in angle of the bent portion 2D. Therefore, according to this embodiment, it is possible to absorb dimensional variations in mass-produced products and improve the robustness of dimensional accuracy in mass production.

[0079] The adjustment range of the adjustment amount H in this embodiment is significantly smaller than that of the adjustment amount T in the first embodiment. This is because, in the adjustment of the adjustment amount H, the effect of the angle change is much larger than the effect on the wall warpage (see FIG. 22) caused by the change in the molding amount of the cam molding. In other words, in this embodiment, the shape of the molded product 2 is adjusted mainly by adjusting the angle change.

[0080] Here, the adjustment amount H may be adjusted based on the material characteristic value of the metal plate S. For example, the tensile strength of the metal sheet S is used as the material characteristic value. In general, the higher the tensile strength of the metal sheet S, the greater the springback amount tends to be. In view of this, when the tensile strength of the metal sheet S to be processed is high, the adjustment amount H of the opposing distance of the cam driver 32 is set to be smaller than when the tensile strength of the metal sheet S to be processed is low.

[0081] As a result, the amount of springback of the formed product 2 is adjusted such that the higher the tensile strength of the metal plate S, the smaller the amount of forming by the second forming is. In this adjustment, the amount of springback of the formed product 2 is adjusted in a feedforward manner.

[0082] Also, a shape measurement may be performed on all or a part of the previously molded product 2, and the adjustment amount H may be adjusted based on the shape measurement. In other words, the adjustment amount H is changed based on the angle change of the bent portion 2D that actually occurs in the previously molded product 2.

[0083] For example, if it is determined that the angle change of the bent portion 2D in the predecessor product exceeds the target value, the adjustment amount H of the cam driver 32 is adjusted to be smaller than the current amount. Also, if it is determined that the angle change of the bent portion 2D in the predecessor product is smaller than the target value, the adjustment amount H is adjusted to be larger than the current amount. In this adjustment, the amount of springback of the formed product 2 is adjusted in a feedback manner.

[0084] Here, by using the adjustment of the height adjustment amount T in the first embodiment together with the adjustment of the adjustment amount H, the wall warp is also adjusted together with the adjustment of the angle change. In this case, it is possible to further adjust the shape of the molded product 2. In this case, as shown in the embodiment described later, a slight change in the wall warp occurs due to the adjustment of the adjustment amount H. It is preferable to adjust the height adjustment amount T taking into account the change in the wall warp due to the adjustment of the adjustment amount H, but the change in the wall warp due to the adjustment of the adjustment amount H may be ignored.

[0085] (others) The present disclosure may also have the following configuration. (1) A press-forming apparatus for manufacturing a press-formed product from a metal plate, the press-formed product having a top plate portion and a vertical wall portion continuous with the top plate portion in a width direction, a punch having a top plate forming surface that contacts a top plate region, which is a region that becomes a top plate portion of the metal plate, from below, and a vertical wall forming surface that forms the vertical wall portion; A pad that presses the top plate area from above; a cam driver disposed at a side of the punch opposite the vertical wall forming surface, the cam driver having an inclined sliding surface inclined so as to approach the punch side from the upper side to the lower side; a bending blade for executing a first forming step, which has a cam slider surface that slides on the inclined sliding surface and comes into contact with the metal plate during forming to bend the metal plate at the boundary between the region that will become the vertical wall portion and the top plate region by sliding on the inclined sliding surface, and a second forming step, which, after guiding on the inclined sliding surface is completed, moves downward to sandwich the region that will become the vertical wall portion between the punch and the bending blade to form the vertical wall portion; At least one or both of a height adjustment mechanism that changes the vertical position of the inclined sliding surface of the cam driver and an opposing distance adjustment mechanism that adjusts the opposing distance of the cam driver to the vertical wall molding surface; A press molding apparatus comprising: (2) A press molding apparatus as described in (1), characterized in that it is equipped with the above-mentioned height adjustment mechanism. (3) The amount of vertical adjustment by the height adjustment mechanism is set to be equal to or less than the height of the vertical wall portion. The press molding apparatus according to (2) above, (4) The cam driver is attached to the lower die. The height adjustment mechanism has a wedge inclined surface formed on a part or all of the bottom surface of the cam driver, and a height adjustment tool that is inserted between the lower die and the wedge inclined surface and slides on the wedge inclined surface, and height adjustment is possible depending on the insertion amount of the height adjustment tool. A press molding apparatus according to (2) or (3). (5) The press molding apparatus according to any one of (2) to (4), further comprising the opposing distance adjustment mechanism. (6) A method for manufacturing a press-molded product, in which a press-molded product having a top plate portion and a vertical wall portion continuous in a width direction of the top plate portion is manufactured by press molding a metal plate, a punch having a top plate forming surface for forming a top plate portion of the metal plate and a vertical wall forming surface for forming a vertical wall portion; a cam driver disposed at a side of the punch opposite the vertical wall forming surface, the cam driver having an inclined sliding surface inclined so as to approach the punch side from the upper side to the lower side; a bending blade for forming the vertical wall portion, which slides on the inclined sliding surface during forming to come into contact with the metal plate and start bending the metal plate at a boundary between a region of the metal plate that will become the vertical wall portion and a region of the metal plate that will become the top plate portion; Equipped with a first forming step of guiding the bending blade along the inclined sliding surface and bringing the bending blade into contact with the metal plate while a top plate region, which is a region of the metal plate that will become a top plate portion, is sandwiched and restrained between the punch and the pad, thereby bending the metal plate at a boundary portion between the region that will become the vertical wall portion of the metal plate and the top plate region; and a second forming step of forming the vertical wall portion by sandwiching the region that will become the vertical wall portion between the punch and the bending blade by moving the bending blade downward after the guiding along the inclined sliding surface is completed. As a process before press molding, at least one or both of a first adjustment process of adjusting the height of the inclined sliding surface in order to change the moving path of the bending blade, and a second adjustment process of adjusting the opposing distance of the cam driver to the vertical wall molding surface in order to adjust the clearance between the bending blade and the vertical wall molding surface at the bottom dead center is included. A method for producing a press-molded product comprising the steps of: (7) A method for producing a press-molded product according to (6), comprising the first adjustment step. (8) The adjustment amount of the height of the inclined sliding surface in the first adjustment step is set to be equal to or less than the height of the vertical wall portion. A method for producing a press-molded product according to (7). (9) The first adjustment step changes the height position of the inclined sliding surface based on a material characteristic value of the metal plate. A method for producing a press-molded product according to (7) or (8). (10) The first adjustment step changes the height position of the inclined sliding surface based on a shape measurement result of a preceding molded product. The method for producing a press-molded product according to any one of (7) to (9) above. (11) The method for producing a press-molded product according to any one of (6) to (10), further comprising the second adjustment step. (12) The second adjustment step changes the facing distance based on a material characteristic value of the metal plate. A method for producing a press-molded product according to (11), (13) The second adjustment step changes the facing distance based on a shape measurement result of a preceding molded product. A method for producing a press-molded product according to (11) or (12), EXAMPLES

[0086] Next, examples based on this embodiment will be described. (First embodiment) The first example corresponds to the first embodiment. The apparatus configuration used was the same as that described in the first embodiment. In this embodiment, a set of tools designed so that the inclination angle α of the inclined sliding surface 32A and the cam slider surface 42A is 45 degrees, and a set of tools designed so that the angle α is 60 degrees were prepared. In this embodiment, shim plates of various thicknesses were placed between the cam driver 32 and the lower die 3 to change the height adjustment amount T of the cam driver 32 in the range of 0 mm to 20 mm.

[0087] 12(a) is a plan view showing the dimensions before forming of the metal sheet S to be processed used in this example. That is, a rectangular metal sheet of 200 mm × 50 mm was used as the metal sheet S to be processed. In addition, a steel sheet with a tensile strength of 1500 MPa and a sheet thickness of 1.4 mm and a steel sheet with a tensile strength of 1630 MPa and a sheet thickness of 1.4 mm were used as the metal sheet S to be processed.

[0088] FIG. 12(b) is a diagram showing a target shape of a press-molded product 2 manufactured by press molding. The units of values ​​in FIG. 12 are [mm]. In the cross-sectional view of the hat shape, the target molded product 2 has a width of 40 mm for the top plate portion 2A, a radius of curvature of 10 mm for the bent portion 2D, a length of 40 mm for the vertical wall portion 2B, a height of 50 mm, and a radius of curvature between the vertical wall portion 2B and the flange portion 2C of 10 mm. However, a bead shape was given to the left vertical wall portion 2B. The bead height with respect to the vertical wall portion 2B was 5 mm, and the vertical wall portion 2B and the bead surface were connected to each other by a curved surface with a curvature radius of 5 mm to form a bead shape.

[0089] In this embodiment, the molding conditions were that the die clearance at the top plate portion 2A and the flange portion 2C was 0.05 mm larger than the plate thickness, and the die clearance at the vertical wall portion 2B was 0.35 mm larger than the plate thickness.

[0090] 13 is a schematic side view showing a cross section of an example of the shape of a molded product molded in this embodiment and released from the mold, i.e., after springback. In the cross section of the hat shape, the angle θ between the upper surface of the top plate portion 2A and the upper surface of the flange portion 2C was measured, and the angle θ was used as an evaluation index for the robustness of dimensional accuracy during mass production.

[0091] <Experimental Results> Fig. 14 is a diagram showing the experimental results when metal plates S having tensile strengths of 1500 MPa and 1630 MPa were formed into the hat-shaped formed product 2. Specifically, Fig. 14 is a graph showing the relationship between the height adjustment amount T and the angle θ in the shape of the formed product 2 after springback. The springback amounts of two types of metal plates S with different tensile strengths are compared under the condition that the height adjustment amount T of the cam driver 32 is equal. As can be seen from Fig. 14, the difference in the angle θ due to the difference in tensile strength was a maximum of 1 degree, whether the inclination angle α of the inclined sliding surface 32A was 45 degrees or 60 degrees.

[0092] Also, the effect when the height adjustment amount T of the cam driver 32 is changed from 5 mm to 20 mm is evaluated. As can be seen from FIG. 14, when the inclination angle α of the inclined sliding surface 32A is 45 degrees, the change amount of the angle θ with respect to the change in the height adjustment amount T is 11 degrees. Also, when the inclination angle α is 60 degrees, when the height adjustment amount T is changed from 5 mm to 20 mm, the change amount of the angle θ is 8 degrees. In this way, it was found that the wall warp amount can be adjusted by adjusting the height adjustment amount T. It was also found that the wall warp amount increases according to the height adjustment amount T.

[0093] Figures 15 and 16 show the evaluation results when metal plates S obtained from different positions in the width direction of a large plate cut from a coil and measuring approximately 1 m in width were formed into hat-shaped products.

[0094] The metal plates S obtained from different positions in the width direction are characterized by different initial flatness before forming. In this example, consider a side view of a cross-section that bisects the short side of the metal plate S. Also, for three points, namely two points at both ends of the long side and one point at the center of the long side, consider the shortest distance from the straight line connecting the two end points to the central point and the radius of curvature when the three points are approximated by a curvature circle. Then, the ratio of the radius of curvature to the height difference was used as the evaluation value of the flatness of each metal plate S.

[0095] First, compare the springback amounts of four types of metal plates S with different flatness under the condition that the height adjustment amount T is equal. As can be seen from FIGS. 15 and 16, the difference in the above angle θ was at most 2 degrees when the inclination angle α of the inclined sliding surface 32A was 45 degrees, and at most 4 degrees when the inclination angle α was 60 degrees.

[0096] Also, consider the case where the inclination angle α of the inclined sliding surface 32A is 45 degrees and the height adjustment amount T of the cam driver 32 is changed from 5 mm to 20 mm. As can be seen from FIG. 15, the change amount of the above angle θ in the shape of the molded product 2 after springback was 11 degrees. Further, when the inclination angle α was 60 degrees, as shown in FIG. 16, when the height adjustment amount T was changed from 0 mm to 20 mm, it was shown that the change amount of the above angle θ was 12 degrees.

[0097] Furthermore, from the above, it was found that the larger the above inclination angle, the larger the change amount of the above angle θ with respect to the adjustment amount T. Also, when the inclination angle α was 60 degrees and the adjustment amount H of the opposing position of the cam driver 32 was changed from 0 mm to 0.75 mm, the change amount of the above angle θ was 3.5 degrees.

[0098] <Analysis Results by CAE> FIG. 17 shows the evaluation results when each metal plate S (steel plate) with a tensile strength of 1470 MPa, 1520 MPa, and 1620 MPa and a plate thickness of 1.4 mm was press-formed. At this time, the height adjustment amount T was changed in the range of 0 mm to 20 mm. Specifically, FIG. 17 is a graph showing the relationship between the height adjustment amount T and the above angle θ.

[0099] The springback amounts of three types of metal plates S with different tensile strengths are compared under the condition that the height adjustment amount T is equal. As can be seen from Fig. 17, the difference in the angle θ due to the difference in tensile strength was a maximum of 1 degree when the inclination angle α of the inclined sliding surface 32A was 45 degrees, and a maximum of 1.5 degrees when the inclination angle α was 60 degrees.

[0100] Furthermore, the height adjustment amount T was changed from 5 mm to 20 mm when the inclination angle α of the inclined sliding surface 32A was 45 degrees and when it was 60 degrees. As can be seen from Fig. 17, the change amount of the angle θ was 12 degrees.

[0101] These results, as well as the CAE analysis results, show that by applying the present invention, the reduction in dimensional accuracy robustness caused by variations in the tensile strength of the metal plate S can be offset and absorbed, thereby improving the robustness.

[0102] Fig. 18 shows the results of CAE analysis when the height adjustment amount T of the cam driver 32 is set to 0 mm and 20 mm in the case of applying the press forming based on this embodiment. Specifically, Fig. 18 is a graph showing the difference in stress between the front and rear sides in the plate thickness direction before springback of the formed product 2 as a function of the long side dimension of the metal plate S.

[0103] As can be seen from Figure 18, when the height adjustment amount T is 20 mm, a stress difference is applied between the front and back sides in the plate thickness direction due to bending and unbending deformation of the vertical wall portion 2B of the metal plate S. In the above example of CAE analysis, the inclined sliding surface 32A has an angle of 45 degrees and an angle of 60 degrees. However, the present invention is not limited to this. It has been confirmed that the same effect can be obtained even if the inclination angle α of the inclined sliding surface 32A is 5 degrees or more and less than 90 degrees.

[0104] In addition, in the above-described embodiment, the cases where the metal plate S has a tensile strength of 1470 MPa, 1520 MPa, and 1620 MPa were described. However, the present invention is not limited thereto, and can be suitably applied to steel plates having a tensile strength of 590 MPa or more.

[0105] (Second Embodiment) The second embodiment is an embodiment based on the press forming of the second embodiment. <CAE Analysis Conditions> In this embodiment, the case where the inclination angle α of the inclined sliding surface 32A is 45 degrees and the case where the inclination angle α is 60 degrees were each implemented.

[0106] In addition, in this embodiment, the adjustment amount H was changed in the range of 0 mm to 0.75 mm. As described above, the adjustment amount H is positive in the retracting direction. Also, the state where the clearance between the bending blade 42 and the punch 31 at the bottom dead center is the narrowest was set as the adjustment amount H = 0 mm.

[0107] Here, as the adjustment amount H increases, as shown in FIG. 10, the position where the shoulder portion 42B of the bending blade 42 in the cam forming contacts the metal plate S moves away from the shoulder portion 42B of the punch 31. For this reason, as shown in FIG. 10, in the cam forming, the metal plate S is formed such that the bent portion 2D contacting the shoulder portion 31D of the punch 31 bulges more. Also, as the adjustment amount H increases, as shown in FIG. 11, the clearance between the bending blade 42 and the punch 31 at the bottom dead center becomes wider. Note that the dimensions of the metal plate S and the shape of the molded product 2 are the same as those in the first embodiment. In this embodiment, when the adjustment amount H of the opposing position of the cam driver 32 is 0, the clearance of the top plate portion 2A and the flange portion 2C is set to a value 0.05 mm larger than the thickness of the metal plate S. Also, the clearance of the vertical wall portion 2B is set to a value 0.35 mm larger than the thickness of the metal plate S.

[0108] Also, regarding the angle θ for evaluating the wall opening, the same evaluation as in the first embodiment is performed (see FIG. 13). That is, the angle θ was measured and used as an evaluation index for the dimensional accuracy robustness during mass production.

[0109] <CAE analysis result> FIG. 19 is a side view showing a cross section of the molded product 2 after springback when the adjustment amount H of the cam driver 32 is 0 mm, 0.25 mm, 0.50 mm, and 0.75 mm. The tensile strength of the metal plate S is 1520 MPa. The inclination angle α of the inclined sliding surface 32A of the cam driver 32 is 60 degrees. As can be seen from FIG. 19, the larger the adjustment amount H, the greater the angle change at the bent portion 2D.

[0110] FIG. 20 is a graph showing the relationship between the adjustment amount H and the angle θ when the adjustment amount H is changed in the range of 0 mm to 0.75 mm. FIG. 20 shows the results when each steel plate (metal plate S) with a tensile strength of 1470 MPa, 1520 MPa, and 1620 MPa and a plate thickness of 1.4 mm is press-molded. Note that the condition is that the adjustment amount T is equal. Compare the springback amounts of three types of metal plates S with different tensile strengths. As can be seen from FIG. 20, the difference in the angle θ was at most 0.3 degrees when the inclination angle α of the inclined sliding surface 32A was 45 degrees. When the inclination angle α was 60 degrees, the maximum was 1.2 degrees.

[0111] When the inclination angle α of the inclined sliding surface 32A is 45 degrees, consider the case when the adjustment amount H is changed from 0 mm to 0.75 mm. As can be seen from FIG. 20, the change amount of the angle θ was 3.5 degrees. Also, under the same conditions, when the inclination angle α was 60 degrees, as shown in FIG. 20, the change amount of the angle θ was 7.0 degrees.

[0112] From these results, it was also shown from the CAE analysis results that by applying the present invention, the variation amount can be offset and absorbed against the decrease in dimensional accuracy robustness caused by the variation in the tensile strength of the metal plate S, and the above robustness can be improved.

[0113] FIG. 21 is a graph showing the difference in the front and back surface stresses in the plate thickness direction of the molded product 2 before springback obtained by CAE analysis corresponding to the long side dimension of the metal plate S. The cases where the adjustment amount H is 0 mm and 0.75 mm are shown. As can be seen from Figure 21, when the adjustment amount H was 0.75 mm, the range in which the residual stress is distributed in the bent portion 2D of the molded product 2 expanded, and it was shown that residual stress exists in such a way that the angle change of the bent portion 2D becomes large.

[0114] In the embodiment based on the CAE analysis, the angle of the inclined sliding surface 32A is described as 45 degrees and 60 degrees. However, the present embodiment is not limited to this, and the inclination angle α may be any angle between 5 degrees and less than 90 degrees.

[0115] In the present embodiment, the metal plate S has a tensile strength of 1470 MPa, 1520 MPa, and 1620 MPa. However, the present invention is not limited to these and can be suitably applied to steel plates having a tensile strength of 590 MPa or more. [Explanation of symbols]

[0116] 1 Press forming equipment 2 Press-molded products 2A Top plate 2B Vertical wall section 2C Flange part 2D bends 3 Lower mold 4 Upper mold 31 Punch 31A Top plate molding surface 31B Vertical wall molding surface 31C Flange molding surface 31D Shoulder 32 Cam driver 32A Slanted sliding surface 32B Upper and lower guide surfaces 33 Height adjustment mechanism 33A Slope 33B Tools (shim plate) 33C Actuator 41 Pad 42 Bending blade 42A Cam slider surface 42B Shoulder 42C Vertical wall molding surface 42D flange forming surface 43 Slide rail 50 Opposing distance adjustment mechanism 51 Slider rail for cam driver 52 Cam driver actuator S Metal plate H Adjustment amount of opposing distance T Height adjustment amount α Incline angle θ angle

Claims

1. A press-molding apparatus for manufacturing a press-molded product from a metal plate, the press-molding apparatus comprising a top plate portion and a vertical wall portion continuous with the top plate portion in a width direction thereof, a punch having a top plate forming surface that contacts a top plate region, which is a region that becomes a top plate portion of the metal plate, from below, and a vertical wall forming surface that forms the vertical wall portion; A pad that presses the top plate area from above; a cam driver disposed at a side of the punch opposite the vertical wall forming surface, the cam driver having an inclined sliding surface inclined so as to approach the punch side from the upper side to the lower side; a bending blade for executing a first forming step, which has a cam slider surface that slides on the inclined sliding surface and comes into contact with the metal plate during forming, thereby bending the metal plate at the boundary between the region that will become the vertical wall portion and the top plate region of the metal plate, and a bending blade for executing a second forming step, which, after guiding on the inclined sliding surface is completed, moves downward to sandwich the region that will become the vertical wall portion between the punch and the bending blade, thereby forming the vertical wall portion; At least one or both of a height adjustment mechanism that changes the vertical position of the inclined sliding surface of the cam driver and an opposing distance adjustment mechanism that adjusts the opposing distance of the cam driver to the vertical wall molding surface; A press molding apparatus comprising:

2. 2. The press forming apparatus according to claim 1, further comprising the height adjustment mechanism.

3. The amount of vertical adjustment by the height adjustment mechanism is set to be equal to or less than the height of the vertical wall portion.

3. The press forming apparatus according to claim 2.

4. The cam driver is attached to the lower die, The height adjustment mechanism has a wedge inclined surface formed on a part or all of the bottom surface of the cam driver, and a height adjustment tool that is inserted between the lower die and the wedge inclined surface and slides on the wedge inclined surface, and height adjustment is possible depending on the insertion amount of the height adjustment tool.

3. The press forming apparatus according to claim 2.

5. The press forming apparatus according to any one of claims 2 to 4, further comprising the opposing distance adjustment mechanism.

6. A method for manufacturing a press-molded product, comprising: manufacturing a press-molded product having a top plate portion and a vertical wall portion continuous in a width direction of the top plate portion by press molding from a metal plate, a punch having a top plate forming surface for forming a top plate portion of the metal plate and a vertical wall forming surface for forming a vertical wall portion; a cam driver disposed at a side of the punch opposite the vertical wall forming surface, the cam driver having an inclined sliding surface inclined so as to approach the punch side from the upper side to the lower side; a bending blade for forming the vertical wall portion, which slides on the inclined sliding surface during forming to come into contact with the metal plate and start bending the metal plate at a boundary between a region of the metal plate that will become the vertical wall portion and a region of the metal plate that will become the top plate portion; Equipped with a first forming step of guiding the bending blade along the inclined sliding surface and bringing the bending blade into contact with the metal plate while a top plate region, which is a region of the metal plate that will become a top plate portion, is sandwiched and restrained between the punch and the pad, thereby bending the metal plate at a boundary portion between the region that will become the vertical wall portion of the metal plate and the top plate region; and a second forming step of forming the vertical wall portion by sandwiching the region that will become the vertical wall portion between the punch and the bending blade by moving the bending blade downward after the guiding along the inclined sliding surface is completed. As a process before press molding, at least one or both of a first adjustment process of adjusting the height of the inclined sliding surface in order to change the moving path of the bending blade, and a second adjustment process of adjusting the opposing distance of the cam driver to the vertical wall molding surface in order to adjust the clearance between the bending blade and the vertical wall molding surface at the bottom dead center is included. A method for producing a press-molded product comprising the steps of:

7. 7. The method for producing a press-formed product according to claim 6, further comprising the first adjusting step.

8. The adjustment amount of the height of the inclined sliding surface in the first adjustment step is set to be equal to or less than the height of the vertical wall portion. The method for producing a press-molded product according to claim 7 .

9. The first adjustment step changes a height position of the inclined sliding surface based on a material characteristic value of the metal plate. The method for producing a press-molded product according to claim 7 .

10. The first adjustment step changes the height position of the inclined sliding surface based on a shape measurement result of a preceding molded product. The method for producing a press-molded product according to claim 7 .

11. The method for manufacturing a press-molded product according to any one of claims 6 to 10, further comprising the second adjustment step.

12. The second adjustment step changes the opposing distance based on a material characteristic value of the metal plate. The method for producing a press-molded product according to claim 11.

13. The second adjustment step changes the facing distance based on a shape measurement result of a preceding molded product. The method for producing a press-molded product according to claim 11.

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