Manufacturing method for deep-drawn products

Abstract

The present invention provides a method for manufacturing deep-drawn molded products that is less prone to cracking of the vertical walls at corners. [Solution] The manufacturing method for the deep-drawn product (10, 10i, 10Ai) includes a step of forming the deep-drawn product (10i, 10Ai) by applying a deep-drawn process to a blank (20). The deep-drawn product (10i, 10Ai) includes a bottom plate (11), a vertical wall (12), a ridge portion (13), and a flange (14i, 14Ai). In the forming step, a first bead (15, 151, 152) is formed. The first bead (15, 151, 152) is provided on the flange (14i, 14Ai) corresponding to the boundary between the right edge portion (131, 131a, 131b, 132, 132a, 132b) of the ridge portion (13) and the corner portion (133) of the ridge portion (13), and is positioned away from the ridge portion (13). In the flange (14i, 14Ai), the portion from the ridge (13) to the first bead (15, 151, 152) is flat.

Description

Technical Field

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

Background Art

[0002] For example, deep-drawn formed products are used in cases of battery packs for vehicles. The deep-drawn formed product includes a bottom plate, a vertical wall continuous with the bottom plate, and a flange connected to the vertical wall via a ridge portion. Such a deep-drawn formed product is formed by restraining the outer peripheral portion of a blank with the flange surface of a die and a blank holder, and pressing the central portion of the blank into the die cavity with a punch.

[0003] Patent Document 1 discloses a press die for deep-drawn formed products (deep drawing press die). In the deep drawing press die of Patent Document 1, two drawing beads are provided at the corner portion of the flange surface (material pressing surface) of the die. These drawing beads are connected to a drawing profile that is the ridge portion of the die cavity. The drawing beads are arranged on the material pressing surface substantially parallel to a straight line connecting the center point of the curved portion of the drawing profile and the center of curvature of this curved portion, and with the straight line interposed therebetween.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] For example, when forming a polygonal-shaped deep-drawn part in plan view, cracks in the vertical walls, known as wall breaks, can occur at the corners of the deep-drawn part. Wall breaks occur when, during the forming process, the flange material flows from the corners to the straight edges, resulting in excessive material flow from the flange to the vertical walls at the straight edges, while insufficient material flow from the flange to the vertical walls at the corners. If cracks in the vertical walls occur frequently during the forming of deep-drawn parts, it becomes difficult to obtain the desired deep-drawn part.

[0006] The object of this disclosure is to provide a method for manufacturing a deep-drawn molded product that is less prone to cracking of the vertical walls at the corners. [Means for solving the problem]

[0007] The method for manufacturing a deep-drawn product according to this disclosure comprises the steps of preparing a blank and forming a deep-drawn product by applying a deep-drawn process to the blank. The deep-drawn product includes a base plate, a vertical wall, a ridge portion, and a flange. The vertical wall is continuous with the base plate. The ridge portion is continuous with the vertical wall on the opposite side of the base plate. The flange is connected to the vertical wall via the ridge portion. In the forming step, a first bead is formed. The first bead is provided on the flange corresponding to the boundary between the right edge portion and the corner portion of the ridge portion. The first bead extends from the inner circumference to the outer circumference of the flange. In the flange, the first bead is positioned away from the ridge portion. In the flange, the portion from the ridge portion to the first bead is flat. [Effects of the Invention]

[0008] The method for manufacturing a deep-drawn product according to this disclosure makes it possible to reduce the occurrence of cracks in the vertical walls at the corners. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a perspective view showing an example of a deep-drawn product in the first embodiment. [Figure 2A]Figure 2A is a schematic diagram illustrating the manufacturing method of a deep-drawn product according to the first embodiment. [Figure 2B] Figure 2B is a schematic diagram illustrating the manufacturing method of a deep-drawn product according to the first embodiment. [Figure 2C] Figure 2C is a schematic diagram illustrating the manufacturing method of a deep-drawn product according to the first embodiment. [Figure 2D] Figure 2D is a schematic diagram illustrating the manufacturing method of a deep-drawn product according to the first embodiment. [Figure 3] Figure 3 is a perspective view showing an example of a mold used in the manufacturing method of a deep-drawn product according to the first embodiment. [Figure 4A] Figure 4A is a diagram illustrating the cross-sectional shape of the bead forming section provided in the mold shown in Figure 3. [Figure 4B] Figure 4B illustrates another cross-sectional shape of the bead forming section provided in the mold shown in Figure 3. [Figure 4C] Figure 4C illustrates yet another cross-sectional shape of the bead forming section provided in the mold shown in Figure 3. [Figure 4D] Figure 4D illustrates yet another cross-sectional shape of the bead forming section provided in the mold shown in Figure 3. [Figure 5] Figure 5 is a perspective view showing an example of a deep-drawn product immediately after the molding process according to the manufacturing method of the first embodiment. [Figure 6A] Figure 6A is a diagram illustrating the cross-sectional shape of a bead provided in the deep-drawn product shown in Figure 5. [Figure 6B] Figure 6B illustrates another cross-sectional shape of the bead provided on the deep-drawn product shown in Figure 5. [Figure 6C] Figure 6C illustrates yet another cross-sectional shape of the bead provided on the deep-drawn product shown in Figure 5. [Figure 6D] Figure 6D illustrates yet another cross-sectional shape of the bead provided on the deep-drawn product shown in Figure 5. [Figure 7] Figure 7 is a plan view of the deep-drawn product shown in Figure 5. [Figure 8]Figure 8 is a longitudinal sectional view of the draw-formed product shown in Figure 5. [Figure 9] Figure 9 is another longitudinal sectional view of the draw-formed product shown in Figure 5. [Figure 10] Figure 10 is a perspective view showing an example of the draw-formed product immediately after the forming step of the manufacturing method according to the second embodiment. [Figure 11] Figure 11 is a perspective view showing an example of a die used in the method for manufacturing a draw-formed product according to the second embodiment. [Figure 12A] Figure 12A is a sectional view of the die shown in Figure 11, and is a schematic diagram for explaining the method for manufacturing a draw-formed product according to the second embodiment. [Figure 12B] Figure 12B is a sectional view of the die shown in Figure 11, and is a schematic diagram for explaining the method for manufacturing a draw-formed product according to the second embodiment. [Figure 13] Figure 13 is a plan view of a draw-formed product in a modification of the first embodiment. [Figure 14] Figure 14 is a plan view of a draw-formed product in another modification of the first embodiment. [Modes for Carrying Out the Invention]

[0010] The method for manufacturing a draw-formed product according to the embodiment includes a step of preparing a blank, and a step of subjecting the blank to drawing to form the draw-formed product. The draw-formed product includes a bottom plate, a vertical wall, a ridge portion, and a flange. The vertical wall is continuous with the bottom plate. The ridge portion is continuous with the vertical wall on the side opposite to the bottom plate. The flange is connected to the vertical wall via the ridge portion. In the forming step, a first bead is formed. The first bead is provided on the flange corresponding to the boundary between the straight side portion of the ridge portion and the corner portion of the ridge portion. The first bead extends from the inner peripheral side to the outer peripheral side of the flange. In the flange, the first bead is arranged at a distance from the ridge portion. In the flange, the portion from the ridge portion to the first bead is flat (First configuration).

[0011] In the manufacturing method relating to the first configuration, a first bead is formed on the flange during the process of forming the deep-drawn product. The first bead is provided on the flange corresponding to the boundary between the straight edge portion of the ridge line continuous with the vertical wall and the corner portion of the said ridge line, and extends from the inner circumference to the outer circumference of the flange. This first bead makes it difficult for material to flow from the corner portion to the straight edge portion in the flange during the forming of the deep-drawn product. As a result, the flow of material from the flange to the vertical wall at the corner is promoted. Therefore, cracking of the vertical wall at the corner is less likely to occur.

[0012] In the manufacturing method relating to the first configuration, the first bead of the flange is positioned away from the ridge. The portion of the flange from the ridge to the first bead is flat. In this case, the drawn product is easier to assemble to other parts. For example, the flat portion of the flange can be brought into surface contact with other parts and joined to them by spot welding or the like. The portion of the flange on which the first bead is provided may be removed before joining the drawn product to other parts.

[0013] In the manufacturing method relating to the first configuration, the angle that the first bead makes with respect to the straight edge at the corner portion may be 40° or more and 95° or less (second configuration).

[0014] With respect to the manufacturing method relating to the first or second configuration, the end of the first bead on the edge side may be positioned less than 100 mm from the boundary between the straight edge and the corner in the direction of extension of the straight edge (third configuration).

[0015] In a manufacturing method relating to any of the first to third configurations, the distance from the ridge to the ridge-side end of the first bead may be 13 mm or more (fourth configuration).

[0016] In a manufacturing method relating to any of the first to fourth configurations, a second bead extending parallel to the straight edge may be further formed on the flange during the molding process (fifth configuration).

[0017] In the manufacturing method relating to the fifth configuration, a first bead and a second bead are formed on the flange during the process of forming the deep-drawn product. The second bead extends parallel to the right edge of the flange. This second bead suppresses the flow of material into the vertical wall at the right edge during the forming of the deep-drawn product. As a result, the flow of material into the vertical wall at the corner is more easily promoted, and cracking of the vertical wall at the corner is less likely to occur.

[0018] Embodiments of this disclosure will be described below with reference to the drawings. In these drawings, the same or equivalent components are denoted by the same reference numerals, and the same description will not be repeated.

[0019] <First Embodiment> [Composition of a deep-drawn product] Figure 1 is a perspective view showing an example of a deep-drawn product 10 manufactured by the manufacturing method according to this embodiment. The deep-drawn product 10 has a polygonal shape in plan view. In the example of Figure 1, the deep-drawn product 10 has a rectangular shape in plan view. The deep-drawn product 10 includes a bottom plate 11, vertical walls 12, ridges 13, and flanges 14.

[0020] The vertical wall 12 is continuous with the base plate 11. The vertical wall 12 is continuous with the periphery of the base plate 11 and rises from the base plate 11. In a plan view of the drawn product 10, the vertical wall 12 surrounds the base plate 11.

[0021] In the example in Figure 1, the vertical wall 12 includes a pair of right-sided sections 121a, 121b, a pair of right-sided sections 122a, 122b, and four corner sections 123. The right-sided sections 121a, 121b face each other in the longitudinal direction of the deep-drawn product 10, for example. The right-sided sections 122a, 122b face each other in the short direction of the deep-drawn product 10, for example. The right-sided sections 121a, 121b, 122a, 122b may each have a flat shape. The right-sided section 121a is connected to each of the right-sided sections 122a, 122b via the corner section 123. The right-sided section 121b is connected to each of the right-sided sections 122a, 122b via the corner section 123 on the opposite side of the right-sided section 121a. Each of the corner portions 123 has a curved shape that is convex outward from the deep-drawn product 10 in a plan view of the deep-drawn product 10. Each of the corner portions 123 extends in the depth direction of the deep-drawn product 10. Hereafter, unless otherwise necessary, the straight edges 121a and 121b will be collectively referred to as the straight edge portion 121, and the straight edges 122a and 122b will be collectively referred to as the straight edge portion 122.

[0022] The ridge portion 13 is continuous with the vertical wall 12 on the opposite side of the base plate 11. The ridge portion 13 is continuous around the entire circumference of the vertical wall 12. In the example of Figure 1, the ridge portion 13 includes a pair of right edges 131a, 131b, a pair of right edges 132a, 132b, and four corner portions 133. The right edges 131a, 131b, 132a, 132b are continuous with the right edges 121a, 121b, 122a, 122b of the vertical wall 12, respectively. The right edges 131a, 131b extend, for example, in the short direction of the drawn product 10. The right edges 132a, 132b extend, for example, in the longitudinal direction of the drawn product 10. Each of the straight edges 131a, 131b, 132a, and 132b can have a substantially straight shape in a plan view of the deep-drawn product 10. The straight edge 131a is connected to each of the straight edges 132a and 132b via a corner portion 133. The straight edge 131b is connected to each of the straight edges 132a and 132b via a corner portion 133 on the opposite side of the straight edge 131a. Each of the corner portions 133 is continuous with the corner portion 123 of the vertical wall 12. The corner portion 133 corresponds to the corner portion 123 of the vertical wall 12 and has a curved shape that is convex outward from the deep-drawn product 10 in a plan view of the deep-drawn product 10. Hereinafter, unless there is a particular need to distinguish between them, the straight edges 131a and 131b will be collectively referred to as the straight edge 131, and the straight edges 132a and 132b will be collectively referred to as the straight edge 132.

[0023] The flange 14 is continuous with the ridge portion 13. The flange 14 is continuous around the entire circumference of the ridge portion 13. In a plan view of the drawn product 10, the flange 14 protrudes outward from the ridge portion 13. The flange 14 is connected to the vertical wall 12 via the ridge portion 13.

[0024] [Method for manufacturing drawn-out products] Next, the method for manufacturing a deep-drawn product according to this embodiment will be described with reference to Figures 2A to 2D. The manufacturing method according to this embodiment comprises a preparation step and a molding step.

[0025] (preparation process) As shown in Figure 2A, a blank 20 is prepared in the preparation step. The blank 20 is composed of, for example, one or more steel plates. However, the blank 20 may be composed of one or more non-ferrous metal plates. In the example in Figure 2A, the blank 20 has a rectangular shape in plan view. However, the blank 20 may have a shape other than a rectangle in plan view.

[0026] (molding process) As shown in Figures 2B to 2D, in the molding process, the blank 20 is subjected to a drawing process to form a drawn product 10i. A mold 30 can be used in the molding process. Figure 3 is a perspective view showing an example of a mold 30 used in the manufacturing method according to this embodiment. As shown in Figure 3, the mold 30 includes a die 31, a punch 32, and a blank holder 33.

[0027] In the example shown in Figure 3, the die 31 includes a bottom portion 311, a peripheral wall portion 312, a shoulder portion 313, and a flange surface 314.

[0028] The die 31 has a cavity 31C. In this embodiment, the cavity 31C is defined by a bottom portion 311 and a peripheral wall portion 312. The bottom portion 311 may be configured to be movable (up and down) relative to the peripheral wall portion 312 by a cushioning mechanism or the like. However, the cavity 31C does not necessarily have to have a bottom portion 311. The cavity 31C has a polygonal shape in a plan view of the die 31. The cavity 31C can have, for example, a rectangular shape in a plan view of the die 31.

[0029] In this embodiment, the peripheral wall portion 312 includes a pair of right-sided portions 3121a, 3121b, a pair of right-sided portions 3122a, 3122b, and four corner portions 3123. The right-sided portions 3121a, 3121b face each other, for example, in the longitudinal direction of the cavity 31C. The right-sided portions 3122a, 3122b face each other, for example, in the short direction of the cavity 31C. The right-sided portions 3121a, 3121b, 3122a, 3122b may each be planar. The right-sided portion 3121a is connected to each of the right-sided portions 3122a, 3122b via the corner portion 3123. The right-sided portion 3121b is connected to each of the right-sided portions 3122a, 3122b via the corner portion 3123 on the opposite side of the right-sided portion 3121a. Each of the corner portions 3123 has a curved shape that is convex towards the outer circumference of the cavity 31C in a plan view of the die 31. Each of the corner portions 3123 extends in the depth direction of the cavity 31C. Hereafter, unless otherwise necessary, the straight edges 3121a and 3121b will be collectively referred to as the straight edge portion 3121, and the straight edges 3122a and 3122b will be collectively referred to as the straight edge portion 3122.

[0030] The shoulder portion 313 is continuous with the peripheral wall portion 312 on the opposite side of the base plate 11. The shoulder portion 313 extends around the entire circumference of the peripheral wall portion 312. In the example of Figure 3, the shoulder portion 313 includes a pair of right-angle portions 3131a, 3131b, a pair of right-angle portions 3132a, 3132b, and four corner portions 3133. The right-angle portions 3131a, 3131b, 3132a, 3132b are continuous with the right-angle portions 3121a, 3121b, 3122a, 3122b of the peripheral wall portion 312, respectively. The right-angle portions 3131a, 3131b extend, for example, in the short-side direction of the cavity 31C. The right-angle portions 3132a, 3132b extend, for example, in the longitudinal direction of the cavity 31C. Each of the straight edges 3131a, 3131b, 3132a, and 3132b can be substantially straight in a plan view of the die 31. The straight edge 3131a is connected to each of the straight edges 3132a and 3132b via a corner portion 3133. The straight edge 3131b is connected to each of the straight edges 3132a and 3132b via a corner portion 3133 on the opposite side of the straight edge 3131a. Each of the corner portions 3133 is continuous with the corner portion 3123 of the peripheral wall portion 312. The corner portion 3133 corresponds to the corner portion 3123 of the peripheral wall portion 312 and has a curved shape that is convex to the outer circumference of the cavity 31C in a plan view of the die 31. Hereafter, unless otherwise necessary, the straight edges 3131a and 3131b will be collectively referred to as straight edge 3131, and the straight edges 3132a and 3132b will be collectively referred to as straight edge 3122.

[0031] The flange surface 314 is continuous with the shoulder portion 313. The flange surface 314 is continuous around the entire circumference of the shoulder portion 313. The flange surface 314 is connected to the peripheral wall portion 312 via the shoulder portion 313. In a plan view of the die 31, the flange surface 314 surrounds the cavity 31C.

[0032] The punch 32 has a shape that corresponds to the cavity 31C of the die 31. The punch 32 may have an uneven shape or holes. When the mold 30 is in use, the punch 32 faces the bottom 311 of the die 31. When the mold 30 is in use, the punch 32 is positioned inside the frame-shaped blank holder 33. The blank holder 33 faces the flange surface 314 of the die 31.

[0033] The flange surface 314 of the die 31 has at least one bead forming portion 315. The bead forming portion 315 may have a convex or concave shape relative to the rest of the flange surface 314. The bead forming portion 315 may also be a stepped portion formed on the flange surface 314.

[0034] In this embodiment, multiple bead forming sections 315 are arranged near each corner section 3133 of the shoulder section 313. Specifically, in the vicinity of each corner section 3133 of the flange surface 314, a bead forming section 315 is provided corresponding to the boundary between the corner section 3133 and the straight edge section 3131, and a bead forming section 315 is also provided corresponding to the boundary between the corner section 3133 and the straight edge section 3132.

[0035] The bead forming portion 315 extends from the inner circumference to the outer circumference of the flange surface 314. The bead forming portion 315 may extend to the outer peripheral edge of the flange surface 314, or it may not reach the outer peripheral edge of the flange surface 314. However, the bead forming portion 315 is not connected to the shoulder portion 313. That is, the bead forming portion 315 is positioned at a distance from the shoulder portion 313 on the flange surface 314. The portion of the flange surface 314 from the shoulder portion 313 to the bead forming portion 315 is a flat surface. The portion of the flange surface 314 adjacent to the shoulder portion 313 may be a flat surface extending around the entire circumference of the shoulder portion 313.

[0036] Figures 4A to 4D illustrate the cross-sectional shape of the bead forming section 315. Figures 4A to 4D show the cross-section of the mold 30 when cut across the bead forming section 315 (the cross-section along line IV-IV in Figure 3).

[0037] Referring to Figures 4A to 4D, the blank holder 33 is provided with a bead forming section 331 corresponding to the bead forming section 315 of the die 31. The bead forming section 331 is provided on the surface of the blank holder 33 facing the flange surface 314 of the die 31. In the example of Figure 4A, the bead forming section 315 of the die 31 is convex, while the bead forming section 331 of the blank holder 33 is concave. In the example of Figure 4B, the bead forming section 315 of the die 31 is concave, while the bead forming section 331 of the blank holder 33 is convex. In the examples of Figures 4C and 4D, both the bead forming section 315 of the die 31 and the bead forming section 331 of the blank holder 33 are stepped. In Figures 4C and 4D, the bead forming portion 315 is formed on the flange surface 314 of the die 31 such that the corner portion 3133 side (Figure 3) is higher than the straight edge portions 3131 and 3132 side (Figure 3). In Figure 4D, compared to Figure 4C, the bead forming portion 315 is formed on the flange surface 314 such that the height of the flange surface 314 changes gradually from the corner portion 3133 side towards the straight edge portions 3131 and 3132 side. However, the bead forming portion 315 may also be formed on the flange surface 314 such that the corner portion 3133 side is lower than the straight edge portions 3131 and 3132 side.

[0038] As described above, the mold 30 can be used in the molding process. Figures 2B to 2D show a cross-section of the mold 30 (cross-section along line II-II in Figure 3) when cut along the extending direction of the bead forming section 315 at the position of the bead forming section 315. Referring to Figure 2B, the blank 20 is placed between the die 31, the punch 32 and the blank holder 33 when the molding process is carried out. If the die 31 is positioned below the punch 32 and the blank holder 33, the blank 20 may be placed on the flange surface 314 of the die 31.

[0039] Referring to Figure 2C, in the molding process, the blank 20 is first clamped between the die 31 and the blank holder 33. More specifically, the flange surface 314 of the die 31 and the blank holder 33 clamp the outer circumference of the blank 20. At this time, a bead 15 is formed on the outer circumference of the blank 20 by the bead forming section 315 provided on the flange surface 314 of the die 31 and the bead forming section 331 provided on the blank holder 33.

[0040] Referring to Figure 2D, next, with the outer periphery of the blank 20 sandwiched between the flange surface 314 of the die 31 and the blank holder 33, the central part of the blank 20 is pushed into the cavity 31C of the die 31 by the punch 32. The portion of the blank 20 pushed into the cavity 31C is formed into a bottom plate 11 and vertical walls 12. The vertical walls 12 are formed by the peripheral wall portion 312 of the die 31 and the punch 32. The bottom plate 11 may be formed by the bottom portion 311 of the die 31 and the punch 32, or it may be formed by the punch 32 alone. When the blank 20 is pushed into the cavity 31C, the blank 20 is bent along the shoulder portion 313 of the die 31 to form a ridge portion 13. The portion of the blank 20 sandwiched between the flange surface 314 of the die 31 and the blank holder 33 becomes a flange 14i. This results in the formation of a deep-drawn product 10i, which includes a base plate 11, a vertical wall 12, a ridge portion 13, and a flange 14i.

[0041] Figure 5 is a perspective view of the deep-drawn product 10i immediately after the molding process. Referring to Figure 5, in the molding process, at least one bead 15 is formed on the flange 14i connected to the vertical wall 12 via the ridge portion 13. In this embodiment, in the molding process, multiple beads 15 are formed near each corner portion 133 of the ridge portion 13. Specifically, in the vicinity of each corner portion 133 of the flange 14i, a bead 15 is provided corresponding to the boundary between the corner portion 133 and the straight edge portion 131, and a bead 15 is also provided corresponding to the boundary between the corner portion 133 and the straight edge portion 132.

[0042] The bead 15 extends from the inner circumference to the outer circumference of the flange 14i. The bead 15 may extend to the outer edge of the flange 14i. However, the bead 15 is not connected to the ridge portion 13. That is, the bead 15 is positioned at a distance from the ridge portion 13 on the flange 14i. The portion of the flange 14i from the ridge portion 13 to the bead 15 is substantially flat. The portion of the flange 14i adjacent to the ridge portion 13 may be flat around the entire circumference of the ridge portion 13.

[0043] The bead 15 may have a convex or concave shape relative to the rest of the flange 14i. The bead 15 may also be a stepped portion formed on the flange 14i. Figures 6A to 6D illustrate the cross-sectional shape of the bead 15 (cross-sectional view along line VI-VI in Figure 5). Figures 6A to 6D show the cross-section of the drawn product 10i when cut across the bead 15 extending to the outer circumference of the flange 14i.

[0044] In the example in Figure 6A, the bead 15 has a convex shape on the side opposite to where the bottom plate 11 (Figure 5) is located. In the example in Figure 6B, the bead 15 has a concave shape on the side where the bottom plate 11 is located. As shown in Figures 6C and 6D, the bead 15 may also be a stepped portion. In Figures 6C and 6D, the bead 15 is formed on the flange 14i such that the corner portion 133 side (Figure 5) is higher than the straight edge portions 131 and 132 side (Figure 5). In the example in Figure 6D, compared to the example in Figure 6C, the bead 15 is formed on the flange 14i such that the height of the flange 14i changes gradually from the corner portion 133 side towards the straight edge portions 131 and 132 side. However, the bead 15 may also be formed on the flange 14i such that the corner portion 133 side is lower than the straight edge portions 131 and 132 side.

[0045] Figure 7 is a plan view of the deep-drawn product 10i, showing an enlarged view of one of the corner portions 133 and its vicinity. Referring to Figure 7, the bead 15 extends in a direction intersecting the extending direction of the right-sided portions 131 and 132 of the ridge portion 13 in a plan view of the deep-drawn product 10i. When the bead 15 provided corresponding to the boundary between the corner portion 133 and the right-sided portion 131 is called bead 151, the angle θ1 that bead 151 makes with respect to the right-sided portion 131 on the corner portion 133 side may be 40° or more and 95° or less. When the bead 15 provided corresponding to the boundary between the corner portion 133 and the right-sided portion 132 is called bead 152, the angle θ2 that bead 152 makes with respect to the right-sided portion 132 on the corner portion 133 side may be 40° or more and 95° or less. It is preferable that angles θ1 and θ2 are 45° or more. The angles θ1 and θ2 are preferably 90° or less. The angles θ1 and θ2 may be equal or different. In other words, the beads 151 and 152 may be provided parallel or non-parallel on the flange 14i.

[0046] Figure 8 is a cross-sectional view taken along line VIII-VIII of Figure 7. Figure 8 shows the cross-section (longitudinal section) of the drawn product 10i when it is cut perpendicular to the extending direction of the right side portion 131 at the end of the bead 151 on the ridge portion 13 side. The end of the bead 151 on the ridge portion 13 side is defined as the position where a virtual straight line L1 (Figure 7), parallel to the right side portion 131 in a plan view of the drawn product 10i, touches the bead 151. Figure 9 is a cross-sectional view taken along line IX-IX of Figure 7. Figure 9 shows the cross-section (longitudinal section) of the drawn product 10i when it is cut perpendicular to the extending direction of the right side portion 132 at the end of the bead 152 on the ridge portion 13 side. The end of the bead 152 on the ridge portion 13 side is defined as the position where a virtual straight line L2 (Figure 7), parallel to the right side portion 132 in a plan view of the drawn product 10i, touches the bead 152.

[0047] Referring to Figures 8 and 9, the flange 14i includes a flat section 141. The flat section 141 is provided in the flange 14i in the range from the ridge section 13 to the beads 151 and 152. The flat section 141 is continuous with the ridge section 13. The flat section 141 may also be continuous around the entire circumference of the ridge section 13.

[0048] The flat portion 141 can be substantially straight in a longitudinal cross-sectional view of the drawn product 10i. On the other hand, the ridge portion 13 can be curved in a longitudinal cross-sectional view of the drawn product 10i. The ridge portion 13 is a bent portion provided between the flat portion 141 and the vertical wall 12. The vertical wall 12 can be substantially straight in a longitudinal cross-sectional view of the drawn product 10i, at least in the portion adjacent to the ridge portion 13.

[0049] Referring to Figure 8, the distance X1 from the ridge portion 13 to the end of the bead 151 on the ridge portion 13 side is, for example, 13 mm or more. Distance X1 is the shortest distance from the boundary between the ridge portion 13 and the flat portion 141 on the outer surface of the flange 14i to the bead 151. In other words, distance X1 is the length of the flat portion 141 between the ridge portion 13 and the bead 151. Distance X1 is preferably 15 mm or more. Distance X1 may be 50 mm or less, or 32 mm or less.

[0050] Referring to Figure 9, the distance X2 from the ridge portion 13 to the end of the bead 152 on the ridge portion 13 side is, for example, 13 mm or more. Distance X2 is the shortest distance from the boundary between the ridge portion 13 and the flat portion 141 on the outer surface of the flange 14i to the bead 152. In other words, distance X2 is the length of the flat portion 141 between the ridge portion 13 and the bead 152. Distance X2 is preferably 15 mm or more. Distance X2 may be 50 mm or less, or 32 mm or less. The distance X2 from the ridge portion 13 to the bead 152 may be equal to or different from the distance X1 from the ridge portion 13 to the bead 151 (Figure 8).

[0051] Returning to Figure 7, the end of the bead 151 on the ridge portion 13 side is positioned at a distance Y1 from the boundary between the straight ridge portion 131 and the curved corner portion 133 in the direction of extension of the straight edge portion 131. Distance Y1 is the distance along the direction of extension of the straight edge portion 131 from the boundary between the straight edge portion 131 and the corner portion 133 on the boundary line between the ridge portion 13 and the flange 14i in a plan view of the drawn product 10i to the end of the bead 151 on the ridge portion 13 side. When distance Y1 is defined as positive if the end of the bead 151 on the ridge portion 13 side is shifted toward the straight edge portion 131 side, and negative if the end of the bead 151 on the ridge portion 13 side is shifted toward the corner portion 133 side, with respect to the boundary between the straight edge portion 131 and the corner portion 133, distance Y1 may be less than 100 mm. In other words, the end of the bead 151 on the ridge portion 13 side may be positioned less than 100 mm from the boundary between the straight edge portion 131 and the corner portion 133 in the direction of extension of the straight edge portion 131. The distance Y1 is preferably 50 mm or less, and more preferably 30 mm or less. The distance Y1 is, for example, -10 mm or more, and preferably 0 mm or more. In the direction of extension of the straight edge portion 131, the position of the end of the bead 151 on the ridge portion 13 side may coincide with the position of the boundary between the straight edge portion 131 and the corner portion 133, but it does not have to coincide.

[0052] The end of the bead 152 on the ridge portion 13 side is positioned at a distance Y2 from the boundary between the straight edge portion 132 and the curved corner portion 133 in the direction of extension of the straight edge portion 132. Distance Y2 is the distance along the direction of extension of the straight edge portion 132 from the boundary between the straight edge portion 132 and the corner portion 133 on the boundary line between the ridge portion 13 and the flange 14i in a plan view of the drawn product 10i to the end of the bead 152 on the ridge portion 13 side. When distance Y2 is defined as positive if the end of the bead 152 on the ridge portion 13 side is shifted toward the straight edge portion 132 side, and negative if the end of the bead 152 on the ridge portion 13 side is shifted toward the corner portion 133 side, relative to the boundary between the straight edge portion 132 and the corner portion 133, distance Y2 may be less than 100 mm. In other words, the end of the bead 152 on the ridge portion 13 side may be positioned less than 100 mm from the boundary between the straight edge portion 132 and the corner portion 133 in the extending direction of the straight edge portion 132. The distance Y2 is preferably 50 mm or less, and more preferably 30 mm or less. The distance Y2 is, for example, -10 mm or more, and preferably 0 mm or more. The distance Y2 may be equal to or different from the distance X2. In the extending direction of the straight edge portion 132, the position of the end of the bead 152 on the ridge portion 13 side may coincide with the position of the boundary between the straight edge portion 132 and the corner portion 133, but may not coincide.

[0053] The manufacturing method according to this embodiment may include a trimming step in addition to the preparation step and the molding step. In the trimming step, the outer periphery of the flange 14i is removed from the deep-drawn product 10i. Specifically, the portion where the bead 15 was formed is removed, and the flange 14i is cut so that the flat portion 141 remains. This makes it possible to obtain the deep-drawn product 10 shown in Figure 1.

[0054] [effect] In the manufacturing method according to this embodiment, beads 151 and 152 are formed on the flange 14i during the process of forming the deep-drawn product 10i. The beads 151 and 152 are provided on the flange 14i corresponding to the boundary between the straight edges 131 and 132 and the corner portion 133 of the ridge portion 13, and extend from the inner circumference to the outer circumference of the flange 14i. These beads 151 and 152 suppress the flow of material from the corner portion 133 side to the straight edges 131 and 132 side in the flange 14i during the forming of the deep-drawn product 10i. As a result, the flow of material from the flange 14i to the corner portion 123 of the vertical wall 12 is promoted. Therefore, cracks are less likely to occur at the corner portion 123 of the vertical wall 12.

[0055] The beads 151 and 152 of the flange 14i are positioned away from the ridge portion 13. The portion of the flange 14i between the beads 151 and 152 and the ridge portion 13 is a flat portion 141. In this case, after forming the deep-drawn product 10i, the beads 151 and 152 can be removed from the flange 14i while leaving the flat portion 141. Therefore, the deep-drawn product 10 after the beads 151 and 152 have been removed can be easily assembled to other parts. Specifically, the flat portion 141 of the flange 14 can be brought into surface contact with other parts and joined to them by spot welding or the like. The flange 14 may also be joined to other parts by a combination of spot welding and adhesive. In this case, grooves for adhesive may be provided in the flange 14 along the ridge portion 13.

[0056] <Second Embodiment> Figure 10 is a perspective view of the deep-drawn product 10Ai in this embodiment. Figure 10 shows the deep-drawn product 10Ai immediately after the molding process. The deep-drawn product 10Ai differs from the deep-drawn product 10i in the first embodiment (Figure 5) in that the bead 16 is formed on the flange 14Ai.

[0057] Referring to Figure 10, the bead 16 is formed on the flange 14Ai during the molding process of the deep-drawn product 10Ai. In the example in Figure 10, the bead 16 is provided on the flange 14Ai corresponding to the right edges 131 and 132 of the ridge portion 13, respectively. The bead 16 extends parallel to the right edges 131 and 132 in a plan view of the deep-drawn product 10Ai. The bead 16 may be parallel to the right edges 131 and 132, but it may also be slightly inclined with respect to the right edges 131 and 132.

[0058] The bead 16, like the bead 15, is positioned at a distance from the ridge portion 13. In the flange 14Ai, the portion from the ridge portion 13 to the bead 16 is flat. That is, in the flange 14Ai, a flat portion 141 is provided not only between the ridge portion 13 and the bead 15, but also between the ridge portion 13 and the bead 16. The flat portion 141 may be provided so as to surround the ridge portion 13.

[0059] Although not shown in the illustration, the bead 16, like the bead 15, may have a convex or concave shape relative to the other parts of the flange 14Ai. Alternatively, the bead 16 may be a stepped portion formed on the flange 14Ai. In this case, the bead 16 may be formed on the flange 14Ai such that the outer circumference is higher than the inner circumference, or the outer circumference is lower than the inner circumference. On the flange 14Ai, the bead 16 may be provided separately from the bead 15, or it may be provided continuously with the bead 15.

[0060] The deep-drawn product 10Ai can be obtained, for example, by performing a molding process using the mold 30A shown in Figure 11. The mold 30A differs from the mold 30 in the first embodiment (Figure 3) in that a bead forming section 316 is provided on the flange surface 314A of the die 31A.

[0061] The bead forming portion 316 is a part provided on the flange surface 314A of the die 31A for forming the bead 16 (Figure 10). The bead forming portion 316 is formed on the flange surface 314A corresponding to the right edges 3131 and 3132 of the shoulder portion 313 of the die 31A. The bead forming portion 316 extends parallel to the right edges 3131 and 3132 in a plan view of the die 31A. The bead forming portion 316 may be parallel to the right edges 3131 and 3132, but it may also be slightly inclined with respect to the right edges 3131 and 3132.

[0062] The bead forming section 316 is positioned at a distance from the shoulder section 313. On the flange surface 314A, the portion from the shoulder section 313 to the bead forming section 316 is a flat surface. That is, on the flange surface 314A, in addition to the space between the shoulder section 313 and the bead forming section 315, the space between the shoulder section 313 and the bead forming section 316 is also a flat surface.

[0063] Although not shown in the figures, the bead forming portion 316 may have a convex shape relative to other parts of the flange surface 314A, or it may have a concave shape, similar to the bead forming portion 315. Alternatively, the bead forming portion 316 may be a stepped portion formed on the flange surface 314A. In this case, the bead forming portion 316 may be formed on the flange surface 314A such that the outer circumference is higher than the inner circumference, or the outer circumference is lower than the inner circumference. On the flange surface 314A, the bead forming portion 316 may be provided separately from the bead forming portion 315, or it may be provided continuously with the bead forming portion 315.

[0064] Figures 12A and 12B show a cross-section of the mold 30A when cut across the bead forming section 316 (cross-section along line XII-XII in Figure 11). As shown in Figures 12A and 12B, the blank holder 33 is provided with a bead forming section 332 corresponding to the bead forming section 316 on the flange surface 314A of the die 31A. During the molding process, when the outer circumference of the blank 20 is clamped between the flange surface 314A of the die 31A and the blank holder 33, a bead 16 is formed on the flange 14Ai by the bead forming sections 316 and 332.

[0065] In the manufacturing method according to this embodiment, similar to the first embodiment, a bead 15 is formed on the flange 14Ai during the process of forming the drawn product 10Ai. Therefore, cracking is less likely to occur at the corner portion 123 of the vertical wall 12. In addition, a bead 16 is formed on the flange 14Ai during the forming process. The bead 16 extends parallel to the straight edges 131 and 132 of the ridge portion 13 on the flange 14Ai, suppressing material inflow into the vertical wall 12 at the straight edges 131 and 132. Therefore, material inflow from the flange 14i to the corner portion 123 of the vertical wall 12 is further promoted, making cracking of the vertical wall 12 at the corner portion 123 less likely.

[0066] In this embodiment as well, a trimming process may be performed after the molding process. In the trimming process, the outer periphery of the flange 14Ai is removed from the drawn product 10Ai. For example, the flange 14Ai is cut so that the portion where the beads 15 and 16 were formed is removed, leaving the flat portion 141. However, the beads 16 corresponding to the straight edges 131 and 132 do not need to be removed from the flange 14Ai by the trimming process. When joining the trimmed flange 14Ai to other parts using adhesive, the beads 16 may be used as grooves for the adhesive.

[0067] While embodiments relating to this disclosure have been described above, this disclosure is not limited to the embodiments described above, and various modifications are possible as long as they do not deviate from its spirit.

[0068] In the molding step of the manufacturing method according to the first embodiment described above, for each corner portion 133 of the ridge portion 13, a bead 151 corresponding to the boundary between the corner portion 133 and the straight edge portion 131, and a bead 152 corresponding to the boundary between the corner portion 133 and the straight edge portion 132 are formed on the flange 14i. However, as shown in Figures 13 and 14, in the molding step, only one of the beads 151 and 152 may be formed on the flange 14i. Similarly, in the second embodiment, only one of the beads 151 and 152 may be formed on the flange 14Ai.

[0069] In the molding step of the manufacturing method according to the second embodiment described above, beads 16 are formed on the flange 14Ai corresponding to both the straight edges 131 and 132 of the ridge portion 13. However, in the molding step, beads 16 may be formed on the flange 14Ai corresponding to only one of the straight edges 131 or 132. That is, the flange 14Ai may be provided with only beads 16 extending parallel to the straight edge 131, or with only beads 16 extending parallel to the straight edge 132.

[0070] In the above embodiment, the deep-drawn products 10i and 10Ai have a rectangular shape in plan view. However, the deep-drawn products 10i and 10Ai may have a polygonal shape other than rectangular in plan view. In this case as well, the ridge portion 13 includes a plurality of corner portions 133. In the process of forming the deep-drawn product 10i or 10Ai, it is sufficient that one or both of the beads 151 and 152 are formed on the flange 14i or 14Ai corresponding to at least one corner portion 133. The angles θ1 and θ2 and distances X1, X2, Y1, and Y2 with respect to the beads 151 and 152 can be set in the same manner as in the above embodiment.

[0071] In the above embodiment, the dies 31 and 31A of the molds 30 and 30A are positioned below the punch 32 and the blank holder 33. However, the positional relationship between the dies 31 and 31A and the punch 32 and the blank holder 33 is not limited to this. For example, the die 31 or 31A may be positioned above the punch 32 and the blank holder 33, and the molding process for the drawn product 10i or 10Ai may be carried out. [Examples]

[0072] The present disclosure will be further described below with reference to examples. However, the present disclosure is not limited to the following examples.

[0073] To confirm the effectiveness of this disclosure, an analysis was performed using general-purpose numerical analysis software (LS-DYNA, manufactured by Ansys) to form a deep-drawn product from a blank 20. In this analysis, the blank 20 was a mild steel sheet with a thickness of 0.7 mm. In the mold 30 used for deep drawing, the radius of curvature of the shoulder portion 313 of the die 31 in cross-sectional view was 6 mm, the radius of curvature of the shoulder portion of the punch 32 in cross-sectional view was 10 mm, and the angle that the peripheral wall portion 312 of the die cavity 31C made with the drawing direction was 7°. In addition, the radius of curvature of the corner portion 3123 of the die cavity 31C in plan view (flange surface 314 side) was 30 mm, and the radius of curvature of the corner portion of the punch 32 corresponding to the corner portion 3123 of the die cavity 31C in plan view was 20 mm. The forming depth (drawing depth) of the deep-drawn product was 90 mm.

[0074] In this analysis, the angles θ1 and θ2 of the beads 151 and 152 relative to the straight edges 131 and 132, and the distances X1, X2, Y1, and Y2 from the ridge 13 to the beads 151 and 152 were varied to evaluate the presence or absence of cracks at the corners 123 of the vertical wall 12. The conditions and evaluation results of this analysis are shown in Table 1.

[0075] [Table 1]

[0076] In this analysis, angles θ1 and θ2 were kept the same, so in Table 1, the angle of beads 151 and 152 relative to the straight edges 131 and 132 is shown as θ. Similarly, in this analysis, distances X1 and X2 were kept the same, and distances Y1 and Y2 were kept the same, so in Table 1, the distances X1 and X2 and Y1 and Y2 from the ridge section 13 to beads 151 and 152 are shown as X and Y, respectively. Regarding "cracks in the vertical wall" in Table 1, if the maximum principal strain of the corner section 123 of the vertical wall 12 (from the R end of the base plate 11 to the R start of the ridge section 13) was 0.35 or less, it was evaluated as ○: no wall crack; if the maximum principal strain was greater than 0.35 but 0.40 or less, it was evaluated as △: small wall crack; and if the maximum principal strain exceeded 0.40, it was evaluated as ×: large wall crack.

[0077] Referring to Table 1, Comparative Example 1 is a case in which a deep-drawn product 10i was formed without providing beads on the flange 14i. Comparative Example 2 is a case in which a deep-drawn product 10i was formed by providing beads 151 and 152 on the flange 14i that correspond to the boundary between the straight edges 131 and 132 of the ridge portion 13 and the corner portion 133, but the beads 151 and 152 were connected to the ridge portion 13. In Comparative Example 2, there is no flat portion between the ridge portion 13 and the beads 151 and 152, and the distance X from the ridge portion 13 to the end of the beads 151 and 152 on the ridge portion 13 side is 0 mm. On the other hand, Examples 1 to 8 are cases in which a deep-drawn product 10i was formed by providing beads 151 and 152 on the flange 14i, and the beads 151 and 152 are positioned away from the ridge portion 13. In Examples 1 to 8, a flat section 141 exists between the ridge section 13 and the beads 151 and 152, and the distance X from the ridge section 13 to the end of the beads 151 and 152 on the ridge section 13 side is greater than 0 mm.

[0078] As shown in Table 1, in Comparative Examples 1 and 2, cracks occurred at the corner portions 123 of the vertical wall 12, whereas in each embodiment, cracks did not occur at the corner portions 123 of the vertical wall 12, or the degree of cracking was smaller compared to Comparative Examples 1 and 2. In other words, it was confirmed that cracking of the vertical wall 12 at the corner portions 123 is suppressed by providing beads 151 and 152 corresponding to the boundary between the straight edges 131 and 132 of the ridge portion 13 and the corner portion 133 on the flange 14i and performing deep drawing.

[0079] In Example 1, where the distance X was 7 mm, a slight crack occurred at the corner portion 123 of the vertical wall 12. On the other hand, in Examples 2-5, 7, and 8, where the distance X was 13 mm or more, no crack occurred at the corner portion 123 of the vertical wall 12. Therefore, it is preferable to set the distance from the ridge portion 13 to the end of the bead 151, 152 on the ridge portion 13 side to 13 mm or more.

[0080] In Example 6, where the distance Y was 100 mm, a slight crack occurred at the corner portion 123 of the vertical wall 12. On the other hand, in Examples 2-5, 7, and 8, where the distance Y was less than 100 mm, no crack occurred at the corner portion 123 of the vertical wall 12. Therefore, it is preferable that the ends of the beads 151 and 152 on the ridge portion 13 side be positioned less than 100 mm from the boundary between the straight edge portions 131 and 132 and the corner portion 133 in the direction of extension of the straight edge portions 131 and 132. [Explanation of Symbols]

[0081] 10, 10i, 10Ai: Deep-drawn parts 11: Bottom plate 12: Vertical wall 121,121a,121b,122,122a,122b:Right side part 123: Corner section 13: Ridge section 131,131a,131b,132,132a,132b:Right side part 133: Corner section 14, 14i, 14Ai: Flange 15,151,152: Bead (First Bead) 16: Bead (2nd Bead) 20: Blank

Claims

1. A method for manufacturing a deep drawing product, The process of preparing the blank, A step of forming a drawn product by applying a drawing process to the blank, which includes a bottom plate, a vertical wall continuous with the bottom plate, a ridge portion continuous with the vertical wall on the opposite side of the bottom plate, and a flange connected to the vertical wall via the ridge portion. Equipped with, In the molding process described above, a first bead is formed on the flange corresponding to the boundary between the straight edge portion and the corner portion of the ridge portion, and extending from the inner circumference to the outer circumference of the flange. A manufacturing method in which, in the flange, the first bead is positioned at a distance from the ridge line, and the portion from the ridge line to the first bead is flat.

2. A manufacturing method according to claim 1, A manufacturing method wherein the angle that the first bead makes with respect to the straight edge portion on the corner portion side is 40° or more and 95° or less.

3. A manufacturing method according to claim 1, A manufacturing method wherein the end of the first bead on the ridge side is positioned less than 100 mm from the boundary between the straight edge and the corner in the direction of extension of the straight edge.

4. A manufacturing method according to claim 1, A manufacturing method in which the distance from the ridge portion to the end of the first bead on the ridge portion side is 13 mm or more.

5. A manufacturing method according to claim 1, A manufacturing method wherein, in the molding step, a second bead extending parallel to the straight edge portion is further formed on the flange.

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