Metal plate molding method, raw material metal plate and battery tray

Abstract

The invention relates to a forming method of a metal plate, a raw material metal plate and a battery tray. In a molding method for processing a metal plate and a battery tray, a raw material metal plate (10A) has a predetermined excess length of each side portion and a predetermined corner shape of a corner portion. In the raw material metal plate (10A), the outer shape line (163) of the raw material metal plate (10A) is located on the opposite side of a bottom surface part (110C), namely the outer side, of a folding line formed by a line segment (P1P3) and a line segment (P3P2), in a part of a first side part (15) closer to a blank corner part (17) than a straight line (L11) and parts of the blank corner part (17) and a second side part (16) closer to the blank corner part (17) than a straight line (L21).

Description

Technical Field

[0001] This invention relates to a method for forming metal sheets, raw material metal sheets, and battery trays. Specifically, this invention relates to a method for forming metal sheets with corner shapes, such as deep-drawn square tubes with flanges, raw material metal sheets, and battery trays with corner shapes.

[0002] This application is based on and claims priority to Japanese Patent Application No. 2023-162926, filed in Japan on September 26, 2023, the contents of which are incorporated herein by reference. Background Technology

[0003] Batteries used in electric vehicles and similar applications require not only improved battery cell loading efficiency and lighter weight to extend driving range, but also enhanced collision safety and reduced costs.

[0004] In such batteries, the battery tray that houses the battery cells typically becomes... Figure 1A and Figure 1B The bottom surface, as shown, is a roughly quadrilateral, roughly hexagonal, or other polygonal shape, with its longitudinal walls connected to the outer perimeter of the bottom surface. At the front end of each longitudinal wall, there is a flange that serves as a mating surface with the top cover. Therefore, near the vertices (corners) of the polygonal bottom surface, it is composed of longitudinal wall portions connected to the straight sections on both sides of the bottom corner via edges, and flange portions connected to the longitudinal wall portions via edges. Figure 2 The corner shape shown is preferred. To improve the loading efficiency of the battery cells, the shape is preferably one where the vertical angle of the longitudinal wall relative to the bottom surface does not widen but is closer to vertical (straight wall), and the radius of curvature of each edge connecting the longitudinal wall, bottom surface, and flange is smaller (smaller R). In addition, to improve collision safety, it is preferable to use high-strength metal sheet as the raw material, and to ensure sealing, it is preferable to use integral molding instead of joining based on welding or the like.

[0005] As a method of integrally forming this shape from a raw metal sheet using a common stamping method, namely deep drawing, the method described in Patent Documents 1 to 3 can be considered, for example.

[0006] Patent document 1 discloses that after preforming the bottom corner of the corner shape so that it protrudes outward toward the outside of the molded article, it is molded into a molded article.

[0007] Patent document 2 discloses the following method: after the raw material steel plate is formed, cuts are made on the edges of the flange areas on both sides of the part that forms the longitudinal wall ridge of the deep-drawn square tube to suppress the generation of longitudinal wall cracks and flange wrinkles.

[0008] Furthermore, Patent Document 3 discloses a method in which the gap between the edge of the corner of the die hole and the edge of the blank, which is the raw material metal sheet, is widened during deep drawing, that is, the raw material metal sheet is shaped with protrusions at the corners, thereby suppressing shrinkage flanges and improving formability.

[0009] However, in order to suppress cracks during forming, these methods require the use of materials with good formability, making it difficult to apply high-strength steel plates with low formability.

[0010] Existing technical documents Patent documents Patent Document 1: Japanese Patent No. 7063429 Patent Document 2: Japanese Patent No. 7070820 Patent Document 3: Japanese Patent No. 7216937 Summary of the Invention

[0011] The problem that the invention aims to solve For example, in use Figure 4 The die 1000V shown consists of a punch 200V, a die 100V, and a retainer 300V. It is formed integrally from a raw metal sheet using a common stamping method, namely deep drawing, to produce a die comprising multiple... Figure 2 The corner shape shown Figure 3 In that shape, while the raw material metal sheet is pressed against the die 100V by the holder 300V, the center portion of the raw material metal sheet is pressed from the holder 300V side towards the die 100V side by the punch 200V to form the shape. During this forming process, the outer periphery of the raw material metal sheet, which is sandwiched between the die 100V and the holder 300V, flows towards the center portion to form a corner shape and a longitudinal wall.

[0012] At this time, as Figure 5A As shown, material flows into the inner side during the stamping process. Figure 5B The image roughly illustrates the inflow of material near the corner of the raw material metal plate 10V at this time. Figure 5BPoints a and b on the raw material metal sheet 10V before stamping, shown by the dashed line 410V, move to the positions of points a' and b' on the formed shape, shown by the solid line 411V, as the material flows in. At the center line of the corner portion 144, considering the length between a' and b' along the circumferential direction (perpendicular to the flow direction) of the corner portion 144 and the length between a and b along the circumferential direction on the raw material metal sheet 10V before forming, the length between a' and b' becomes shorter. That is, during deep drawing, the curved flange portion 143V of the corner portion 144 is compressed in the circumferential direction during forming. This phenomenon is generally referred to as a shrinkage flange, which increases the resistance to material flow and inhibits material flow. Therefore, cracks are prone to occur near the vertices (corners) of the polygonal bottom portion 110V and along the corner longitudinal wall edges, and wrinkles are prone to occur in the curved flange portion 143V of the corner portion 144. If the pressure of the retainer is increased, wrinkles can be reduced, but the resistance to material flow increases and cracks become more pronounced.

[0013] In Patent Document 1, preforming can disperse the concentration of deformation at the shoulder, thus effectively suppressing cracks at the corner. However, even with dispersed deformation, a certain degree of strain will still occur, thus limiting the crack suppression effect, and the material needs a certain degree of formability.

[0014] Furthermore, in Patent Document 2, slits are made in the raw material steel plate to reduce the shrinkage flange, thereby effectively reducing material inflow resistance and suppressing crack formation. However, since the shrinkage flange cannot be completely suppressed, some degree of material inflow resistance remains. Therefore, the crack suppression effect is limited, and the material still requires a certain degree of formability.

[0015] Furthermore, Patent Document 3 discloses a method that, during deep drawing, shapes the raw material sheet into a shape with protrusions at the corners, thereby suppressing shrinkage flanges and improving formability. However, this method cannot completely suppress shrinkage flanges, leaving some degree of material inflow resistance. Therefore, the crack suppression effect is limited, and the material requires a certain level of formability.

[0016] In any of the methods disclosed in Patent Documents 1-3, the improvement in formability is limited. In Patent Documents 1-3, to form a shape including corners with high longitudinal wall height, longitudinal walls standing at a near-vertical angle to the bottom surface (straight wall construction), and small radii of curvature of the edges connecting the longitudinal walls, bottom surface, and flanges (small R-shape), the material requires a certain degree of formability. Therefore, it is difficult to apply materials with low formability in any of the methods disclosed in Patent Documents 1-3. On the other hand, generally, the higher the strength of a metal sheet, the lower its formability, making high-strength materials difficult to form. For example, in the case of steel sheets, steel sheets with a tensile strength of 390 MPa or higher present the problem of difficulty in suppressing cracks and wrinkles.

[0017] The inventors conducted in-depth research on deep drawing of shapes including corner shapes and discovered the following:

[0018] For example, Figure 6A The image roughly illustrates the molding process using a rectangular raw material metal sheet 10V. Figure 6A (a) represents before stamping, and (b) represents after stamping. Figure 6A The solid line 410V1 shown in (a) is the outline of the raw material metal sheet 10V1 before stamping. Figure 6A The solid line 411V1 shown in (b) is the outline of the raw material metal sheet 10V1 after stamping. Points a1 and b1 on the raw material metal sheet 10V1 before stamping are moved to the positions of points a1' and b1' on the shape of the raw material metal sheet 10V1 after stamping by the flow of material.

[0019] When using a rectangular raw material metal sheet 10V1 for stamping, such as Figure 6A As shown, in the stamping process, a contraction flange is formed at the centerline of the corner portion 144V1, where the material of the corner portion 144V1 contracts circumferentially (in the direction perpendicular to the flow direction) at the curved flange portion 143V1, increasing the resistance to material flow. This hinders the flow of material.

[0020] exist Figure 6B The diagram shows the forming of the raw material metal sheet 10V2 in a simplified manner. Unlike Patent Document 3, which has a rectangular shape, the raw material metal sheet 10V2 has a blank protrusion 13V2 (diagonal section) protruding outward from the corner 144V2 of the raw material metal sheet 10V2. Figure 6B The billet protrusion 13V2 shown is in Figure 6A The corner 144V1 of the rectangular raw material metal plate 10V1 shown extends outward from the solid line 410V1 of the raw material metal plate 10V1. Figure 6B(a) represents before stamping, and (b) represents after stamping. Figure 6B The solid line 410V2 shown in (a) is the outline of the raw material metal sheet 10V2 before stamping. Figure 6B The solid line 411V2 shown in (b) is the outline of the raw material metal sheet 10V2 after stamping. Points a2 and b2 on the raw material metal sheet 10V2 before stamping are moved to the positions of points a2' and b2' on the shape of the raw material metal sheet 10V2 after stamping by the material flow. At this time, Figure 6B The outline of the blank protrusion 13V2 before stamping shown in (a) becomes Figure 6B The outline of 13V2' as shown in (b). Regarding Figure 6A and Figure 6B The virtual unfolded shape 162 and the end 162E will be described later.

[0021] like Figure 6B As shown, when a blank protrusion 13V2 is provided at the corner 144V2 of the raw material metal sheet 10V2, the shrinkage flange is suppressed. This is because, as Figure 7 The protruding portion (j portion) is not compressed in the circumferential (inward) direction, and therefore is difficult to shrink. As a result, although the material (k portion) located inside the protruding portion 13V2 of the blank is compressed in the inward direction and attempts to shrink, the j portion inhibits the compression of the k portion because it is connected to the k portion. However, if... Figure 6B If the protruding part is only the curved flange 143V2, the material in the curved flange 143V2 will not shrink in the circumferential direction. Therefore, the flange portions (F portions) on both sides of the curved flange 143V2 are compressed, and the flow of material is hindered in these portions.

[0022] exist Figure 6C The diagram schematically illustrates the forming of a raw material metal sheet 10V3 in which the blank protrusion 13V3 extends to a portion of the straight flange portion on both sides. Figure 6C (a) represents before stamping, and (b) represents after stamping. Figure 6C The solid line 410V3 shown in (a) is the outline of the raw material metal sheet 10V3 before stamping. Figure 6C The solid line 411V3 shown in (b) is the outline of the raw material metal sheet 10V3 after stamping. Points a3 and b3 on the raw material metal sheet 10V3 before stamping are moved to the positions of points a3' and b3' on the shape of the raw material metal sheet 10V3 after stamping by the material flow. At this time, Figure 6C The outline of the blank protrusion 13V3 shown in (a) before stamping becomes Figure 6C The 13V3' outline is shown in (b).

[0023] like Figure 6C As shown, by extending the blank protrusion 13V3 of the raw material metal sheet 10V3 to a portion of the straight flange portion on both sides, the compression of the flange portions (F portions) on both sides of the curved flange portion 143V3 is alleviated, and the material flow at the corner portion 144V3 is improved. Furthermore, Figure 6C The billet protrusion 13V3 shown is in Figure 6A The corner 144V1 of the rectangular raw material metal plate 10V1 shown extends outward from the solid line 410V1 of the raw material metal plate 10V1.

[0024] Moreover, such as Figure 8A As shown, if a draw bead is provided on the die and retainer of the mold at a position corresponding to the center of the straight flange portion connected to the longitudinal wall of the raw material metal sheet at the location indicated by the dashed line, the inflow resistance of the straight flange portion is increased and the inflow volume is reduced, thus mitigating the compression of the flange portions (F portions) on both sides of the curved flange portion. Furthermore, Figure 8A The location of the drawbeads 165 on the retainer 300 is shown, but pairs of drawbeads 165 are also provided at the same location on the die 100. As a result, while the inflow at the straight flange portion is somewhat suppressed, the material inflow at the corner portion, which leads to crack formation, is further improved. However, as... Figure 8B As shown, if the draw bead 1650 provided in the retainer 300V is too long, it will hinder the flow of the flange portions (F portions) on both sides of the bent flange portion. Therefore, the draw bead 1650 needs to be set so that it does not reach the F portion.

[0025] Furthermore, the shrinkage flange suppression effect of the protrusion is greater the closer it is to the protrusion (j part) in the material inflow direction, and decreases as the distance increases. Figure 9B The diagram schematically illustrates a case where the portion of the raw material metal sheet other than the protrusion at the corner is formed relative to the raw material metal sheet 10A which is too large in shape. Figure 9A This indicates the inflow of material into the raw material metal plate 10A of one embodiment of the present invention, as described later. Figure 9B This indicates that the shape ratio of the raw material metal sheet 10A is... Figure 9A The inflow of raw material metal sheet 10V4 under the condition of increased situation. Figure 9A The dashed line 410 shows the outline of the raw material metal sheet 10A before stamping, and the solid line 411 shows the outline of the raw material metal sheet 10A after stamping. Points a and b on the raw material metal sheet 10A move to the positions of points a' and b' on the shape of the stamped raw material metal sheet 10A as the material flows in.

[0026] At the centerline of the corner portion 144, if we consider the length between a and b before molding and the length between a' and b' after molding of the curved flange portion 143 of the corner portion 144 along the circumferential direction (perpendicular to the flow direction), although it is slightly shorter and compressed, the compression is suppressed due to the protrusion of the corner portion 144, similar to... Figure 5B Compared to the case without protrusions, the compression is smaller and the contraction of the flange is suppressed.

[0027] Figure 9B The dashed line 410V shows the outline of the raw material metal sheet 10V4 before stamping, and the solid line 411V shows the outline of the raw material metal sheet 10V4 after stamping. Points a and b on the raw material metal sheet 10V4 move to the positions of points a' and b' on the shape of the stamped raw material metal sheet 10V4 as material flows in. Figure 9B Considering the length of the curved flange portion 143V of the corner portion 144V before molding (in the direction perpendicular to the inflow direction) and the length of the flange portion 143V after molding between points a and b, the distance between points a and b in the inflow direction is farther than that of the protruding portion (j portion). Therefore, the compression suppression effect of the protruding portion is greater than that of the central line portion of the corner portion 144V. Figure 9A As the size decreases, the compression increases, the shrinkage flange is not suppressed, and the resistance to material flow increases. Therefore, if the portion of the raw material metal plate 10V4 other than the protruding part at the corner is set to a size below a certain level, the suppression effect of the shrinkage flange will not decrease, and the material flow will increase.

[0028] The present invention was made in view of the above circumstances, and its object is to provide a method for forming a metal sheet, a raw material metal sheet, and a battery tray, for integrally forming a shape using a high-strength metal sheet that includes the following corner shape: it is composed of a bottom part having a corner portion, such as a battery tray, a longitudinal wall portion connected to the straight portions on both sides of the corner portion of the bottom part via ridge lines, a longitudinal wall ridge line connected to each ridge line, and a flange portion connected to the longitudinal wall portion and the longitudinal wall ridge line via ridge lines, wherein the longitudinal wall height is relatively high, the longitudinal wall stands at a near-vertical angle relative to the bottom surface, and the radius of curvature of each ridge line connecting the longitudinal wall, the bottom surface, and the flange is relatively small.

[0029] Methods for solving problems (1) One method for forming a metal sheet according to the present invention involves processing the metal sheet into a shape including corner shapes, wherein, The corner shape includes: The bottom surface has a shape that includes, as part of the outline, a first straight line, a second straight line, and a first curved line connecting the first straight line and the second straight line; The first ridge line is connected to the bottom surface through the first straight line; The second ridge line is connected to the bottom surface through the second straight line; A first curved ridge line is connected to the bottom surface through the first curved line and is also connected to the first ridge line and the second ridge line; The first longitudinal wall rises on the opposite side of the bottom surface, connected to the first ridge line; The second longitudinal wall rises on the opposite side of the bottom surface, connected to the second ridge line; The longitudinal wall edge rises on the opposite side of the bottom surface, connected to the first curved edge, and is connected to the first longitudinal wall and the second longitudinal wall; The third ridge line is connected to the first longitudinal wall on the opposite side of the first ridge line; The fourth ridge line is connected to the second longitudinal wall on the opposite side of the second ridge line; The second curved edge line connects to the longitudinal wall edge line on the opposite side of the first curved edge line and connects the third edge line to the fourth edge line; The first flange is connected to the third ridge on the opposite side of the first longitudinal wall and extends substantially horizontally; The second flange, on the opposite side of the second longitudinal wall, connects to the fourth ridge and extends substantially horizontally; and A curved flange portion, connected to the second curved ridge on the opposite side of the longitudinal wall ridge, extends substantially horizontally and connects the first flange portion and the second flange portion. In the molding method, When observing a cross-section of the corner shape in a plane perpendicular to the outline of the bottom surface at various positions on the outline of the bottom surface, which is formed by the first straight line, the second straight line, and the first curved line, the length of the cross-section from the outline of the bottom surface to the end of the product is defined as the outer length of the bottom surface at each position of the outline of the bottom surface. The shape at each position on the outline of the bottom surface, in a direction parallel to and perpendicular to the outline of the bottom surface, extending the outer length of the bottom surface at each position on the outline of the bottom surface, is defined as a virtual unfolded shape. The portion of the outline of the virtual unfolded shape that extends from the first straight line on the bottom surface is designated as the third straight line. The portion of the outline of the virtual unfolded shape that extends from the first curved line on the bottom surface is designated as the second curved line, and the portion of the outline of the virtual unfolded shape that extends from the second straight line on the bottom surface is designated as the fourth straight line. In this case, the shape of the portion of the raw material metal sheet including the corner shape is: when viewed at various positions on the outline of the bottom surface in a cross-section in a plane perpendicular to the outline of the bottom surface, it is the same as the virtual unfolded shape or extends further than the virtual unfolded shape in a direction parallel to and perpendicular to the outline of the bottom surface. The length of the excess material α is defined as the length from the outline of the virtual unfolded shape to the outline of the raw material metal plate at each cross-sectional position. Furthermore, the junction of the first straight line and the first curved line is designated as point b1, and the junction of the second straight line and the first curved line is designated as point b2. Let the line passing through point b1, parallel to the bottom surface, and perpendicular to the first straight line be designated as the first normal line L1; let the line passing through point b2, parallel to the bottom surface, and perpendicular to the second straight line be designated as the second normal line L2; and let the intersection of the first normal line L1 and the second normal line L2 be designated as point O. The side of the raw material metal plate outside the bottom surface and that does not include the second curvature line relative to the first normal L1 is designated as the first edge; the side of the raw material metal plate outside the bottom surface and that does not include the second curvature line relative to the second normal L2 is designated as the second edge; and the area between the first normal L1 and the second normal L2 outside the bottom surface of the raw material metal plate is designated as the blank corner. The distance from the bottom surface to the curved flange in the direction perpendicular to the bottom surface of the corner shape is defined as the height h of the corner shape. When observing the remaining material length α along the first straight line from the first normal L1 in the direction opposite to the corner of the billet at the first edge of the raw material metal plate, if the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value is within 3h from the first normal L1, then the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value from the first normal L1 is set as the remaining material standing position of the first edge. If no minimum value is reached within 3h from the first normal L1, then the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value within 3h from the first normal L1 is set as the remaining material standing position of the first edge. The distance from the first normal L1 to the remaining material standing position of the first edge is set as C1, and the remaining material length at that position is set as α1. When observing the remaining material length α along the second straight line from the second normal L2 in the direction opposite to the corner of the billet at the second edge of the raw material metal plate, if the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value is within 3h from the second normal L2, then the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value from the second normal L2 is set as the remaining material standing position of the second edge. If it does not reach its minimum value within 3h from the second normal L2, then the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value within 3h from the second normal L2 is set as the remaining material standing position of the second edge. The distance from the second normal L2 to this remaining material standing position of the second edge is set as C2, and the remaining material length at this position is set as α2. The intersection point P1 is defined as the point where the straight line L11, which has been moved parallel to the first normal L1 towards the first edge by a length C1, intersects the outline of the raw material metal plate. The intersection point P2 is defined as the point where the straight line L21, which has been moved parallel to the second normal L2 towards the second edge by a length C2, intersects the outline of the raw material metal plate. Let the intersection point P3 be the line that passes through the intersection point P1 and is parallel to the first line, and the line that passes through the intersection point P2 and is parallel to the second line. In this case, in the portion of the first side closer to the corner of the billet than the straight line L11, and in the portion of the billet corner and the second side closer to the corner of the billet than the straight line L21, the outline of the raw material metal plate is positioned on the opposite side (outer side) of the bottom surface than the broken line formed by line segments P1P3 and P3P2. Furthermore, when the intersection points of the line passing through intersection point P3 and perpendicular to the line connecting intersection points O and P3 with the outline of the raw material metal plate are defined as intersection points Q1 and Q2, and the length of line segment Q1Q2 is defined as length B, and the length of line segment P1P2 is defined as length D, the following conditions are met: 0 < α1 ≤ h (Equation 1) 0 < α² ≤ h (Equation 2), Further satisfy: 0.3D≤B (Equation 3).

[0030] (2) In the manner described in (1) above, it can also be: The forming method includes a stamping process and a finishing process. Let C be the distance from the line segment Q1Q2 to the point on the outer contour line of the raw material metal plate between the intersection points Q1 and Q2 that is furthest away. On the side of the first edge opposite to the corner of the billet relative to the first normal L1 and on the side of the second edge opposite to the corner of the billet relative to the second normal L2, the following conditions are met: 0 < α < 3h (Equation 4), Further satisfy: 0.3D≤B≤1.5D (Equation 5) 0≤C≤2B (Equation 6).

[0031] (3) In one aspect of the present invention, the raw material metal sheet is a raw material metal sheet being formed into a shape including corners during the forming process, wherein... The corner shape includes: The bottom surface has a shape that includes, as part of the outline, a first straight line, a second straight line, and a first curved line connecting the first straight line and the second straight line; The first ridge line is connected to the bottom surface through the first straight line; The second ridge line is connected to the bottom surface through the second straight line; A first curved ridge line is connected to the bottom surface through the first curved line and is also connected to the first ridge line and the second ridge line; The first longitudinal wall rises on the opposite side of the bottom surface, connected to the first ridge line; The second longitudinal wall rises on the opposite side of the bottom surface, connected to the second ridge line; The longitudinal wall edge rises on the opposite side of the bottom surface, connected to the first curved edge, and is connected to the first longitudinal wall and the second longitudinal wall; The third ridge line is connected to the first longitudinal wall on the opposite side of the first ridge line; The fourth ridge line is connected to the second longitudinal wall on the opposite side of the second ridge line; The second curved edge line connects to the longitudinal wall edge line on the opposite side of the first curved edge line and connects the third edge line to the fourth edge line; The first flange is connected to the third ridge on the opposite side of the first longitudinal wall and extends substantially horizontally; The second flange, on the opposite side of the second longitudinal wall, connects to the fourth ridge and extends substantially horizontally; and A curved flange portion, connected to the second curved ridge on the opposite side of the longitudinal wall ridge, extends substantially horizontally and connects the first flange portion and the second flange portion. In the raw material metal plate, When observing a cross-section of the corner shape in a plane perpendicular to the outline of the bottom surface at various positions on the outline of the bottom surface, which is formed by the first straight line, the second straight line, and the first curved line, the length of the cross-section from the outline of the bottom surface to the end of the product is set as the outer length of the bottom surface at each position of the outline of the bottom surface. The shape at each position on the outline of the bottom surface, in a direction parallel to and perpendicular to the outline of the bottom surface, extending the outer length of the bottom surface at each position on the outline of the bottom surface, is defined as a virtual unfolded shape. The portion of the outline of the virtual unfolded shape that extends from the first straight line on the bottom surface is designated as the third straight line. The portion of the outline of the virtual unfolded shape that extends from the first curved line on the bottom surface is designated as the second curved line, and the portion of the outline of the virtual unfolded shape that extends from the second straight line on the bottom surface is designated as the fourth straight line. In this case, the shape of the corner portion of the raw material metal sheet is: when viewed from various positions on the outline of the bottom surface, in a cross-section of a plane perpendicular to the outline of the bottom surface, it is the same as the virtual unfolded shape or extends further than the virtual unfolded shape in a direction parallel to and perpendicular to the outline of the bottom surface. The length of the excess material α is defined as the length from the outline of the virtual unfolded shape to the outline of the raw material metal plate at each cross-sectional position. Furthermore, the junction of the first straight line and the first curved line is designated as point b1, and the junction of the second straight line and the first curved line is designated as point b2. Let the line passing through point b1, parallel to the bottom surface, and perpendicular to the first straight line be designated as the first normal line L1; let the line passing through point b2, parallel to the bottom surface, and perpendicular to the second straight line be designated as the second normal line L2; and let the intersection of the first normal line L1 and the second normal line L2 be designated as point O. The side of the raw material metal plate outside the bottom surface and that does not include the second curvature line relative to the first normal L1 is designated as the first edge; the side of the raw material metal plate outside the bottom surface and that does not include the second curvature line relative to the second normal L2 is designated as the second edge; and the area between the first normal L1 and the second normal L2 outside the bottom surface of the raw material metal plate is designated as the blank corner. The distance from the bottom surface to the curved flange in the direction perpendicular to the bottom surface of the corner shape is defined as the height h of the corner shape. When observing the remaining material length α along the first straight line from the first normal L1 in the direction opposite to the corner of the billet at the first edge of the raw material metal plate, if the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value is within 3h from the first normal L1, then the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value from the first normal L1 is set as the remaining material standing position of the first edge. If no minimum value is reached within 3h from the first normal L1, then the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value within 3h from the first normal L1 is set as the remaining material standing position of the first edge. The distance from the first normal L1 to the remaining material standing position of the first edge is set as C1, and the remaining material length at that position is set as α1. When observing the remaining material length α along the second straight line from the second normal L2 in the direction opposite to the corner of the billet at the second edge of the raw material metal plate, if the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value is within 3h from the second normal L2, then the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value from the second normal L2 is set as the remaining material standing position of the second edge. If it does not reach its minimum value within 3h from the second normal L2, then the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value within 3h from the second normal L2 is set as the remaining material standing position of the second edge. The distance from the second normal L2 to this remaining material standing position of the second edge is set as C2, and the remaining material length at this position is set as α2. The intersection point P1 is defined as the point where the straight line L11, which has been moved parallel to the first normal L1 towards the first edge by a length C1, intersects the outline of the raw material metal plate. The intersection point P2 is defined as the point where the straight line L21, which has been moved parallel to the second normal L2 towards the second edge by a length C2, intersects the outline of the raw material metal plate. Let the intersection point P3 be the line that passes through the intersection point P1 and is parallel to the first line, and the line that passes through the intersection point P2 and is parallel to the second line. In this case, in the portion of the first side closer to the corner of the billet than the straight line L11, and in the portion of the billet corner and the second side closer to the corner of the billet than the straight line L21, the outline of the raw material metal plate is positioned on the opposite side (outer side) of the bottom surface than the broken line formed by line segments P1P3 and P3P2. Furthermore, when the intersection points of the line passing through intersection point P3 and perpendicular to the line connecting intersection points O and P3 with the outline of the raw material metal plate are defined as intersection points Q1 and Q2, and the length of line segment Q1Q2 is defined as length B, and the length of line segment P1P2 is defined as length D, the following conditions are met: 0 < α1 ≤ h (Equation 1) 0 < α² ≤ h (Equation 2), Further satisfy: 0.3D≤B (Equation 3).

[0032] (4) In the manner described in (3) above, it can also be: Let C be the distance from the line segment Q1Q2 to the point on the outer contour line of the raw material metal plate between the intersection points Q1 and Q2 that is furthest away. On the side of the first edge opposite to the corner of the billet relative to the first normal L1 and on the side of the second edge opposite to the corner of the billet relative to the second normal L2, the following conditions are met: 0 < α < 3h (Equation 4), Further satisfy: 0.3D≤B≤1.5D (Equation 5) 0≤C≤2B (Equation 6).

[0033] (5) In the manner described in (1) or (2) above, it is also possible to be, A die-drawing device with a die, a punch, and a retainer is used to draw a sheet metal into a shape that includes corners. The corner shape includes: The bottom surface, which is shaped as part of the outline, includes a first straight line, a second straight line, and a first curved line connecting the first straight line and the second straight line; The first ridge line is connected to the bottom surface through the first straight line; The second ridge line is connected to the bottom surface through the second straight line; A first curved ridge line is connected to the bottom surface through the first curved line and is also connected to the first ridge line and the second ridge line; The first longitudinal wall rises on the opposite side of the bottom surface, connected to the first ridge line; The second longitudinal wall rises on the opposite side of the bottom surface, connected to the second ridge line; The longitudinal wall edge rises on the opposite side of the bottom surface, connected to the first curved edge, and is connected to the first longitudinal wall and the second longitudinal wall; The third ridge line is connected to the first longitudinal wall on the opposite side of the first ridge line; The fourth ridge line is connected to the second longitudinal wall on the opposite side of the second ridge line; The second curved edge line connects to the longitudinal wall edge line on the opposite side of the first curved edge line and connects the third edge line to the fourth edge line; The first flange is connected to the third ridge on the opposite side of the first longitudinal wall and extends substantially horizontally; The second flange, on the opposite side of the second longitudinal wall, connects to the fourth ridge and extends substantially horizontally; and A curved flange portion, connected to the second curved ridge on the opposite side of the longitudinal wall ridge, extends substantially horizontally and connects the first flange portion and the second flange portion. In the molding method, When observing a cross-section of the corner shape in a plane perpendicular to the outline of the bottom surface at various positions on the outline of the bottom surface, which is formed by the first straight line, the second straight line, and the first curved line, the length of the cross-section from the outline of the bottom surface to the end of the product is defined as the outer length of the bottom surface at each position of the outline of the bottom surface. The shape at each position on the outline of the bottom surface, in a direction parallel to and perpendicular to the outline of the bottom surface, extending the outer length of the bottom surface at each position on the outline of the bottom surface, is defined as a virtual unfolded shape. The portion of the outline of the virtual unfolded shape that extends from the first straight line on the bottom surface is designated as the third straight line. The portion of the outline of the virtual unfolded shape that extends from the first curved line on the bottom surface is designated as the second curved line, and the portion of the outline of the virtual unfolded shape that extends from the second straight line on the bottom surface is designated as the fourth straight line. In this case, the shape of the corner portion of the raw material metal sheet is: when viewed from various positions on the outline of the bottom surface, in a cross-section of a plane perpendicular to the outline of the bottom surface, it is the same as the virtual unfolded shape or extends further than the virtual unfolded shape in a direction parallel to and perpendicular to the outline of the bottom surface. The length of the excess material α is defined as the length from the outline of the virtual unfolded shape to the outline of the raw material metal plate at each cross-sectional position. Furthermore, the junction of the first straight line and the first curved line is designated as point b1, and the junction of the second straight line and the first curved line is designated as point b2. Let the line passing through point b1, parallel to the bottom surface, and perpendicular to the first straight line be designated as the first normal line L1; let the line passing through point b2, parallel to the bottom surface, and perpendicular to the second straight line be designated as the second normal line L2; and let the intersection of the first normal line L1 and the second normal line L2 be designated as point O. The side of the raw material metal plate outside the bottom surface and that does not include the second curvature line relative to the first normal L1 is designated as the first edge; the side of the raw material metal plate outside the bottom surface and that does not include the second curvature line relative to the second normal L2 is designated as the second edge; and the area between the first normal L1 and the second normal L2 outside the bottom surface of the raw material metal plate is designated as the blank corner. The distance from the bottom surface to the curved flange in the direction perpendicular to the bottom surface of the corner shape is defined as the height h of the corner shape. When observing the remaining material length α along the first straight line from the first normal L1 in the direction opposite to the corner of the billet at the first edge of the raw material metal plate, if the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value is within 3h from the first normal L1, then the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value from the first normal L1 is set as the remaining material standing position of the first edge. If no minimum value is reached within 3h from the first normal L1, then the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value within 3h from the first normal L1 is set as the remaining material standing position of the first edge. The distance from the first normal L1 to the remaining material standing position of the first edge is set as C1. When observing the remaining material length α along the second straight line from the second normal L2 in the direction opposite to the corner of the billet at the second edge of the raw material metal plate, if the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value is within 3h from the second normal L2, then the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value from the second normal L2 is set as the remaining material standing position of the second edge. If it does not reach its minimum value within 3h from the second normal L2, then the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value within 3h from the second normal L2 is set as the remaining material standing position of the second edge. The distance from the second normal L2 to this remaining material standing position of the second edge is set as C2, and the remaining material length at this position is set as α2. Let the straight line on the metal plate be a line that has been moved parallel to the first normal L1 and toward the first edge by a distance of 0.5 times the length C1, and be designated as line L12. Let the straight line on the metal plate that has been moved parallel to the second normal L2 and toward the second edge by a distance of 0.5 times the length C2 be designated as line L22. Draw beads are provided at one or both of the following locations: the first side of the die and the holder, which is located on the opposite side of the blank corner relative to the straight line L12, and the second side, which is located on the opposite side of the blank corner relative to the straight line L22. Draw beads are not provided at the locations corresponding to the die and the holder at the first side, the second side, and the blank corner between the straight lines L12 and L22.

[0034] (6) In the manner described in (1) or (2) above, it can be that, The raw material metal plate is a steel plate with a tensile strength of 390MPa or higher.

[0035] (7) In the manner described in (3) or (4) above, it can be that, The raw material metal plate is a steel plate with a tensile strength of 390MPa or higher.

[0036] (8) In one embodiment of the present invention, the battery tray is a steel plate made of a raw material metal plate with a tensile strength of 390 MPa or higher, and its shape includes a corner shape, wherein... The corner shape includes: The bottom surface has a shape that includes, as part of the outline, a first straight line, a second straight line, and a first curved line connecting the first straight line and the second straight line; The first ridge line is connected to the bottom surface through the first straight line; The second ridge line is connected to the bottom surface through the second straight line; A first curved ridge line is connected to the bottom surface through the first curved line and is also connected to the first ridge line and the second ridge line; The first longitudinal wall rises on the opposite side of the bottom surface of the first ridge; The second longitudinal wall rises on the opposite side of the bottom surface of the second ridge; The longitudinal wall edge rises on the opposite side of the bottom surface, connected to the first curved edge, and is connected to the first longitudinal wall and the second longitudinal wall; The third ridge line is connected to the first longitudinal wall on the opposite side of the first ridge line; The fourth ridge line is connected to the second longitudinal wall on the opposite side of the second ridge line; The second curved edge line connects to the longitudinal wall edge line on the opposite side of the first curved edge line and connects the third edge line to the fourth edge line; The first flange is connected to the third ridge on the opposite side of the first longitudinal wall; The second flange is connected to the fourth ridge line on the opposite side of the second longitudinal wall; and A curved flange portion is connected to the second curved ridge on the opposite side of the longitudinal wall ridge, and connects the first flange portion to the second flange portion. When the distance from the bottom surface to the curved flange in a direction perpendicular to the bottom surface of the corner shape is defined as the corner shape height h, the radius of curvature of the longitudinal wall edge is defined as Rb, the angle between the bottom surface and the first longitudinal wall is defined as E1, and the angle between the bottom surface and the second longitudinal wall is defined as E2, the following conditions are met: 1≤h / Rb≤15 (Equation 7) 90°≤E1<105° (Equation 8) 90°≤E2<105° (Equation 9) Formed from a single sheet of raw metal through stamping, excluding the joints between the raw metal parts, and when the thickness of the raw metal sheet is t, the radius of curvature of the first edge is r1, the radius of curvature of the second edge is r2, the radius of curvature of the third edge is r3, and the radius of curvature of the fourth edge is r4, the following conditions are met: 2.5t≤r1≤0.2h (Equation 10) 2.5t≤r²≤0.2h (Equation 11) 2.5t≤r3≤0.2h (Equation 12) 2.5t≤r4≤0.2h (Equation 13).

[0037] Invention Effects According to the present invention, a high-strength metal sheet is integrally formed into a shape including a corner shape, which is composed of a bottom surface having a corner portion, a longitudinal wall portion connected to straight portions on both sides of the corner portion of the bottom surface portion via ridge lines, a longitudinal wall ridge line connected to each ridge line, and a flange portion connected to the longitudinal wall portion and the longitudinal wall ridge line via ridge lines. This provides a method for forming a metal sheet with high strength, a relatively high longitudinal wall height, the longitudinal wall standing at a near-vertical angle relative to the bottom surface, a small radius of curvature of each ridge line connecting the longitudinal wall, the bottom surface, and the flange, and without any joints based on welding, bonding, etc., as well as a raw material metal sheet and a battery tray. Attached Figure Description

[0038] Figure 1A This is a perspective view showing an example of the shape of a typical battery tray.

[0039] Figure 1B This is a perspective view showing an example of the shape of a typical battery tray.

[0040] Figure 2 It is a magnified 3D view of a corner of a portion of the battery tray.

[0041] Figure 3 It means including multiple Figure 2 A perspective view of an example of a battery tray at the corner of the battery tray shown.

[0042] Figure 4 This is a schematic perspective view used to illustrate an example of a mold assembly.

[0043] Figure 5A It is a schematic diagram used to illustrate the flow of material from the raw material metal sheet.

[0044] Figure 5B It means Figure 5A A schematic diagram of the material flow near the corner of the raw material metal sheet.

[0045] Figure 6A It is a schematic diagram used to illustrate the flow of material from the raw material metal sheet, showing a corner section.

[0046] Figure 6B It is a schematic diagram used to illustrate the flow of material from the raw material metal sheet, showing a corner section.

[0047] Figure 6C It is a schematic diagram used to illustrate the flow of material from the raw material metal sheet, showing a corner section.

[0048] Figure 7 It is a schematic diagram used to illustrate the flow of material from the raw material metal sheet, showing a corner section.

[0049] Figure 8A This is a schematic top view of a retainer used to illustrate an example of a die assembly with draw beads.

[0050] Figure 8B This is a schematic top view of a retainer used to illustrate an example of a die assembly with draw beads.

[0051] Figure 9A It is a schematic diagram used to illustrate the flow of material from the raw material metal sheet, showing a corner section.

[0052] Figure 9B It is a schematic diagram used to illustrate the flow of material from the raw material metal sheet, showing a corner section.

[0053] Figure 10 This is a schematic perspective view of a metal sheet before forming (a), after stamping (b), and after finishing (c) in a metal sheet forming method according to one embodiment of the present invention.

[0054] Figure 11 This is a schematic perspective view illustrating an example of a mold apparatus used in a metal sheet forming method according to one embodiment of the present invention.

[0055] Figure 12 This is an enlarged perspective view of a portion of the corner shape of a battery tray according to one embodiment of the present invention.

[0056] Figure 13 This is a top view showing a portion of the metal plate in this embodiment, near the corner.

[0057] Figure 14 This is a schematic perspective view of a battery tray according to one embodiment of the present invention.

[0058] Figure 15A Therefore, through Figure 14 A schematic sectional view of the battery tray at position A-A' shown.

[0059] Figure 15B Therefore, through Figure 14 A schematic cross-sectional view of the position B-B' of the battery tray shown.

[0060] Figure 16 This is a schematic perspective view used to illustrate an example of a mold assembly.

[0061] Figure 17 This is a top view showing an example of the position of the drawbeads on the die corresponding to the position on the raw material metal plate.

[0062] Figure 18This is a schematic top view of a retainer used to illustrate an example of a die assembly with draw beads.

[0063] Figure 19 This is a schematic perspective view used to illustrate the shape of the embodiment.

[0064] Figure 20A This is a schematic top view of the raw material metal plate used to illustrate the embodiments.

[0065] Figure 20B This is a schematic top view of the raw material metal plate used to illustrate the embodiments.

[0066] Figure 20C This is a schematic top view of the raw material metal plate used to illustrate the embodiments.

[0067] Figure 20D This is a schematic top view of the raw material metal plate used to illustrate the embodiments.

[0068] Figure 21 This is a schematic perspective view illustrating an example of a mold apparatus used in the metal sheet forming method of the embodiment.

[0069] Figure 22A This is a schematic top view of the retainer used to illustrate an embodiment of a die assembly provided with draw beads.

[0070] Figure 22B This is a schematic top view of the retainer used to illustrate an embodiment of a die assembly provided with draw beads.

[0071] Figure 23A This is a schematic perspective view of the final product of the embodiment.

[0072] Figure 23B This is a schematic perspective view of the final product of the embodiment.

[0073] Figure 23C This is a schematic perspective view of the final product of the embodiment.

[0074] Figure 24A This is a schematic perspective view of the final product of the embodiment.

[0075] Figure 24B This is a schematic perspective view of the final product of the embodiment. Detailed Implementation

[0076] The following description illustrates embodiments of the present invention, but the invention is not limited to these examples. Specific values ​​and materials are sometimes shown in the following description, but other values ​​and materials can be used as long as the effects of the present invention are achieved. Furthermore, the constituent elements of the following embodiments can be combined with each other.

[0077] [First Implementation Method] (Metal sheet forming methods) Reference Figures 10 to 15B The forming method of the metal sheet according to this embodiment will be described.

[0078] The metal plate 10 in this embodiment is as follows: Figure 10 The raw material metal sheet 10A is shown in (a). The raw material metal sheet 10A is stamped and formed to become... Figure 10 A metal sheet 10B of the shape shown in (b). The stamped metal sheet 10B is then trimmed to become as shown in [the diagram]. Figure 10 The final product is a metal plate 10C as shown in (c). In the embodiment described later, the metal plate 10C is a battery tray. Thus, the metal plate forming method of this embodiment includes a step of stamping the raw material metal plate 10A and a step of trimming the stamped metal plate 10B.

[0079] The forming method of the metal plate 10 in this embodiment is as follows: the raw material metal plate 10A is processed (cutting (shearing), laser cutting, etc.) into... Figure 13 After shaping it as shown, use Figure 11 The mold 1000W shown consists of a punch 200W, a die 100W, and a retainer 300W. While the retainer 300W applies pressure around the raw material metal sheet 10A and presses it against the die 100W, the punch 200W presses the center portion of the raw material metal sheet 10A from the retainer 300W side towards the die 100W side, thus forming the sheet. The metal sheet 10 is formed by performing the above-described deep drawing process. Figure 12 The method shown includes a molding method for a corner shape 124 formed by a bottom surface 110C, a first ridge 112c, a second ridge 113c, a first curved ridge 152c, a first longitudinal wall 125c, a second longitudinal wall 126c, a longitudinal wall ridge 121c, a third ridge 132c, a fourth ridge 133c, a second curved ridge 131c, a first flange portion 141c, a second flange portion 142c, and a curved flange portion 143c.

[0080] Here, regarding the corner shape 124, the bottom surface 110C is a shape that includes a first straight line 150c, a second straight line 151c, and a first curved line 111c connecting the first straight line 150c and the second straight line 151c as part of the outline.

[0081] The first ridge line 112c is connected to the bottom surface 110C via the first straight line 150c.

[0082] The second ridge line 113c is connected to the bottom surface 110C via the second straight line 151c.

[0083] The first curved ridge 152c is connected to the bottom surface 110C via the first curved ridge 111c and is also connected to the first ridge 112c and the second ridge 113c.

[0084] The first longitudinal wall 125c stands upright on the opposite side of the bottom surface 110C, connected to the first ridge line 112c.

[0085] The second longitudinal wall 126c stands upright on the opposite side of the bottom surface 110C, connected to the second ridge line 113c.

[0086] The longitudinal wall edge 121c stands on the opposite side of the bottom surface 110C, connected to the first curved edge 152c, and is connected to the first longitudinal wall 125c and the second longitudinal wall 126c.

[0087] The third ridge 132c is connected to the first longitudinal wall 125c on the opposite side of the first ridge 112c.

[0088] The fourth ridge 133c is connected to the second longitudinal wall 126c on the opposite side of the second ridge 113c.

[0089] The second curved ridge 131c is connected to the longitudinal wall ridge 121c on the opposite side of the first curved ridge 152c and connects the third ridge 132c with the fourth ridge 133c.

[0090] The first flange portion 141c is connected to the third ridge line 132c on the opposite side of the first longitudinal wall 125c and extends approximately horizontally.

[0091] The second flange portion 142c is connected to the fourth ridge line 133c on the opposite side of the second longitudinal wall 126c and extends approximately horizontally.

[0092] The curved flange portion 143c is connected to the second curved ridge 131c on the opposite side of the longitudinal wall ridge 121c and extends approximately horizontally, connecting the first flange portion 141c and the second flange portion 142c.

[0093] like Figure 13 As shown, protrusions are formed at each corner of the raw material metal plate 10A. Figure 13 The details describe the area near the corner of the raw material metal plate 10A.

[0094] First, use Figure 12 and Figure 13 Define the following: outer length of the bottom face, virtual unfolded shape 162, third straight line 152, second curved line 153, fourth straight line 154.

[0095] The outer length of the bottom part is defined as the length (mm) of the cross section of the corner shape 124 in a plane perpendicular to the outer line 164 of the bottom part 110C, which is formed by the first straight line 150c, the second straight line 151c, and the first curved line 111c. When viewing the cross section of the corner shape 124 in the plane perpendicular to the outer line 164 at various positions on the outer line 164, the length of the cross section from the outer line 164 to the end 162E of the final product of the molded article is defined as the length at each outer line position.

[0096] The virtual unfolded shape 162 is the shape obtained by extending the bottom surface 110C by the outer length of the bottom surface at each position on the outer contour line 164 of the bottom surface 110C in a direction that is parallel to and perpendicular to the outer contour line 164 of the bottom surface 110C.

[0097] The third straight line 152 is the portion of the outline of the virtual unfolded shape 162 that extends from the first straight line 150c on the bottom surface 110C.

[0098] The second curved line 153 is the portion of the outline of the virtual unfolded shape 162 that extends vertically from various positions of the first curved line 111c on the bottom surface 110C.

[0099] The fourth straight line 154 is the portion of the outline of the virtual unfolded shape 162 that extends from the second straight line 151c on the bottom surface 110C.

[0100] When viewing cross-sections in planes perpendicular to the outline 164 of the bottom surface 110C at various locations on the outline 164 of the bottom surface 110C, the shape of the portion of the raw material metal sheet 10A formed into the corner shape 124 is the same as the virtual unfolded shape 162, or is a shape that is further extended than the virtual unfolded shape 162 in a direction parallel to the bottom surface 110C and perpendicular to the outline 164 of the bottom surface 110C.

[0101] Furthermore, it is defined as follows.

[0102] The length extending from the outline of the virtual unfolded shape 162 to the outline 163 of the raw material metal plate 10A at each cross-sectional position is defined as the excess material length α (mm). In other words, the excess material length α is the vertical distance from the outline of the virtual unfolded shape 162.

[0103] The junction of the first straight line 150c and the first curved line 111c is designated as point b1.

[0104] The junction of the second straight line 151c and the first curved line 111c is designated as point b2.

[0105] Let the line passing through point b1, parallel to the bottom surface 110C, and perpendicular to the first straight line 150c be the first normal line L1.

[0106] Let the line passing through point b2, parallel to the bottom surface 110C, and perpendicular to the second line 151c be the second normal line L2.

[0107] Let point O be the intersection of the first normal L1 and the second normal L2.

[0108] The side of the raw material metal plate 10A other than the bottom surface 110C and which does not include the second curvature line 153 relative to the first normal L1 is designated as the first edge 15.

[0109] The side of the raw material metal plate 10A other than the bottom surface 110C and which does not include the second curvature line 153 relative to the second normal line L2 is designated as the second side 16.

[0110] The blank corner 17 is defined as the area outside the bottom part 110C of the raw material metal plate 10A and between the first normal line L1 and the second normal line L2.

[0111] like Figure 15A and Figure 15B As shown, the distance from the bottom surface 110C to the curved flange 143c in the direction perpendicular to the bottom surface 110C of the corner shape 124 is defined as the corner shape height h (mm).

[0112] like Figure 13 As shown, in the first edge 15 of the raw material metal plate 10A, when observing the remaining material length α along the first straight line 150c from the first normal L1 in the direction opposite to the blank corner 17, if the position on the outer line 163 of the raw material metal plate 10A where the remaining material length α first reaches its minimum value is within 3h from the first normal L1, then the position on the outer line 163 of the raw material metal plate 10A where the remaining material length α first reaches its minimum value from the first normal L1 is set as the remaining material standing position P1 (intersection P1) of the first edge 15. If the remaining material length α does not reach its minimum value within 3h from the first normal L1, then the position on the outer line 163 of the raw material metal plate 10A where the remaining material length α first reaches its minimum value within 3h from the first normal L1 is set as the remaining material standing position P1 of the first edge 15.

[0113] The distance from the first normal L1 to the standing position P1 of the first edge 15 is set as C1, and the length of the remaining material at that position is set as α1 (mm).

[0114] like Figure 13As shown, in the second side 16 of the raw material metal plate 10A, when observing the remaining material length α along the second straight line 151c in the direction opposite to the blank corner 17 from the second normal line L2, if the position on the outer line 163 of the raw material metal plate 10A where the remaining material length α first reaches its minimum value is within 3h from the second normal line L2, then the position on the outer line 163 of the raw material metal plate 10A where the remaining material length α first reaches its minimum value from the second normal line L2 is set as the remaining material standing position P2 (intersection point P2) of the second side 16. If the remaining material length α does not reach its minimum value within 3h from the second normal line L2, then the position on the outer line 163 of the raw material metal plate 10A where the remaining material length α first reaches its minimum value within 3h from the second normal line L2 is set as the remaining material standing position P2 of the second side 16.

[0115] Let C2 be the distance from the second normal L2 to the position P2 where the excess material is erected on the second side 16, and let α2 (mm) be the length of the excess material at that position.

[0116] The line that has been moved parallel to the first normal L1 by a length C1 toward the first side 15 is designated as line L11.

[0117] Let the line that has been moved parallel to the second normal L2 by a length C2 toward the second side 16 be line L21.

[0118] Let the intersection point P3 be the intersection point of the line that passes through intersection point P1 and is parallel to the first line 150c and the line that passes through intersection point P2 and is parallel to the second line 151c.

[0119] As defined above, in the portion of the first side 15 closer to the blank corner 17 than the straight line L11, and in the portions of the blank corner 17 and the second side 16 closer to the blank corner 17 than the straight line L21, the outline 163 of the raw material metal plate 10A is located on the opposite side of the bottom part 110C, i.e., on the outer side, than the broken line formed by line segments P1P3 and P3P2.

[0120] Furthermore, when the intersection points of the line passing through intersection point P3 and perpendicular to the line connecting intersection points O and P3, and the outline line 163 of the raw material metal plate 10A are defined as intersection points Q1 and Q2, and the length of line segment Q1Q2 is defined as length B (mm), and the length of line segment P1P2 is defined as length D (mm), the following conditions are met: 0 < α1 ≤ h (Equation 1) 0 < α2 ≤ h (Equation 2).

[0121] Further satisfy: 0.3D≤B (Equation 3).

[0122] In this embodiment, the metal plate 10 is stamped into a shape including the corner shape 124 as described above.

[0123] According to this embodiment, a shape including the desired corner shape can be integrally molded without joints based on welding, bonding, etc. Therefore, it exhibits excellent formability and can suppress wrinkles and cracks.

[0124] Let C (mm) be the distance from line segment Q1Q2 to the point on the outermost line 163 of the raw material metal plate 10A between intersection point Q1 and intersection point Q2.

[0125] On the side opposite to the blank corner 17 relative to the first normal L1 of the first side 15 and on the side opposite to the blank corner 17 relative to the second normal L2 of the second side 16, the following can be satisfied: 0 < α < 3h (Equation 4).

[0126] It can also be further satisfied: 0.3D≤B≤1.5D (Equation 5) 0≤C≤2B (Equation 6).

[0127] As a result, it has better formability and can further suppress wrinkles and cracks.

[0128] Here, the lengths of the remaining material α, α1, and α2 are explained (Equations 1, 2, and 4).

[0129] If we assume that the cross-sectional length of the raw material metal sheet 10A does not increase due to stamping, then the outline of the virtual unfolded shape 162 on the raw material metal sheet 10A becomes the end 162E of the final product. Here, the final product refers to the processed metal sheet obtained by further trimming its outer periphery after the raw material metal sheet 10A has been stamped into a shaped form. Figure 10 (c) of 10C). Therefore, when α, α1, and α2 are set to 0, the positions P1 and P2 are located on the outline of the virtual unfolded shape 162, and thus after forming, positions P1 and P2 become the ends 162E of the final product. The metal sheet that becomes the formed shape after stamping ( Figure 10 When (b) of 10B) is finished to produce the final product, there is no excess material that becomes a finishing allowance. In fact, due to the elongation of the profile line length due to stamping, a certain amount of excess material is generated, but due to the low extensibility of high-strength materials, the excess material is very small.

[0130] In actual stamping processes, deviations in stamping conditions can lead to variations in the shape of the stamped product. Therefore, to obtain a product with a high-precision shape, it is necessary to trim the outer periphery after stamping to form the final product. However, in trimming high-strength raw material sheet 10A, when the remaining material is minimal and the cut-off section is short, burrs easily form on the sheared surface, resulting in a rough, low-quality end face. To obtain a burr-free, high-quality end face, the cut-off section needs to be a certain length of remaining material.

[0131] Therefore, the raw material metal plate 10A needs to be in a shape where the lengths of the surplus material α, α1, and α2 are greater than 0.

[0132] Furthermore, the shrinkage flange suppression effect of the protruding portion between positions P1 and P2 of the raw material metal plate 10A is greater the closer it is to the protruding portion and less the further it is from the protruding portion, the less effective it becomes. Therefore, if the excess material lengths α1 and α2 are too large, the bent flange portion 143c will be further away from the protruding portion, thus reducing the shrinkage flange suppression effect and making it easier for cracks to form. Therefore, the excess material lengths α1 and α2 are preferably set to be less than or equal to the corner height h.

[0133] Furthermore, the size of the excess material at the straight edge has a relatively small impact on cracks during stamping. However, if it is too large, the portion to be removed after stamping the raw material sheet 10A becomes larger. As a result, the material yield decreases and the manufacturing cost increases. Therefore, the excess material length α is preferably set to be less than or equal to the corner height h.

[0134] The relationship between the length B of line segment Q1Q2 and the length D of line segment P1P2 is explained (Equations 3 and 5).

[0135] If the width of the protruding portion at a certain distance from the intersection point O is too small, the shrinkage flange suppression effect of the protruding portion between positions P1 and P2 at the corner of the raw material metal plate 10A becomes insufficient. Therefore, the length B is preferably 0.3 or more relative to the length D of the root of the protruding portion.

[0136] Furthermore, when the length B is too large relative to the length D, the shape of the protruding part becomes such that the width of the front end is wider than the width of the root, and the sides are concave. As a result, deformation is concentrated at the ends of the sides, making it prone to cracking. Therefore, it is preferable that B ≤ 1.5D.

[0137] The distance C from line segment Q1Q2 to the point on the outermost line 163 of the raw material metal plate 10A between intersection point Q1 and intersection point Q2, and the length B of line segment Q1Q2 are explained (Equation 6).

[0138] If the protrusion of the corner portion of the raw material metal plate 10A is insufficient, the shrinkage flange suppression effect will be insufficient. Therefore, the shape of the raw material metal plate 10A between position P1 and position P2 is preferably located on the opposite side of the bottom surface, i.e., the outer side, than the broken line formed by line segments P1P3 and P3P2, where 0≤C.

[0139] Furthermore, if the protrusion exceeds a certain level, the shrinkage flange suppression effect will not change significantly. However, if the protrusion is too large, the portion to be removed after stamping the raw material metal sheet 10A becomes larger. As a result, the material yield decreases and the manufacturing cost increases. Therefore, C ≤ 2B is preferred.

[0140] The raw material metal plate 10A can be a steel plate with a tensile strength of 390MPa or higher. Because the raw material metal plate 10A has a tensile strength of 390MPa or higher, it is lightweight and possesses excellent strength.

[0141] (raw material metal plate) Reference Figures 10 to 15B The raw material metal plate of this embodiment will be described.

[0142] In this embodiment, the raw material metal plate 10A is formed into a shape containing... Figure 12 The raw material metal sheet in the forming of the corner shape 124 shown is a metal sheet, which is composed of a bottom surface 110C, a first ridge 112c, a second ridge 113c, a first curved ridge 152c, a first longitudinal wall 125c, a second longitudinal wall 126c, a longitudinal wall ridge 121c, a third ridge 132c, a fourth ridge 133c, a second curved ridge 131c, a first flange portion 141c, a second flange portion 142c, and a curved flange portion 143c.

[0143] The bottom surface 110C is a shape that includes a first straight line 150c, a second straight line 151c, and a first curved line 111c connecting the first straight line 150c and the second straight line 151c as part of the outline.

[0144] The first ridge line 112c is connected to the bottom surface 110C via the first straight line 150c.

[0145] The second ridge line 113c is connected to the bottom surface 110C via the second straight line 151c.

[0146] The first curved ridge 152c is connected to the bottom surface 110C via the first curved ridge 111c and is also connected to the first ridge 112c and the second ridge 113c.

[0147] The first longitudinal wall 125c stands upright on the opposite side of the bottom surface 110C, connected to the first ridge line 112c.

[0148] The second longitudinal wall 126c stands upright on the opposite side of the bottom surface 110C, connected to the second ridge line 113c.

[0149] The longitudinal wall edge 121c stands on the opposite side of the bottom surface 110C, connected to the first curved edge 152c, and is connected to the first longitudinal wall 125c and the second longitudinal wall 126c.

[0150] The third ridge 132c is connected to the first longitudinal wall 125c on the opposite side of the first ridge 112c.

[0151] The fourth ridge 133c is connected to the second longitudinal wall 126c on the opposite side of the second ridge 113c.

[0152] The second curved ridge 131c is connected to the longitudinal wall ridge 121c on the opposite side of the first curved ridge 152c and connects the third ridge 132c with the fourth ridge 133c.

[0153] The first flange portion 141c is connected to the third ridge line 132c on the opposite side of the first longitudinal wall 125c and extends approximately horizontally.

[0154] The second flange portion 142c is connected to the fourth ridge line 133c on the opposite side of the second longitudinal wall 126c and extends approximately horizontally.

[0155] The curved flange portion 143c is connected to the second curved ridge 131c on the opposite side of the longitudinal wall ridge 121c and extends approximately horizontally, connecting the first flange portion 141c and the second flange portion 142c.

[0156] Regarding the external length of the bottom part, when observing the cross-section of the corner shape 124 in the plane perpendicular to the corner shape 164 of the bottom part 110C, which is formed by the first straight line 150c, the second straight line 151c, and the first curved line 111c at various positions on the outline line 164 of the bottom part 110C, the length of the cross-section from the outline line 164 to the end 162E of the final product is set as the length (mm) at each outline line position of the bottom part 110C.

[0157] The virtual unfolded shape 162 is a shape that extends the bottom surface 110C by the outer length of the bottom surface at each position on the outer contour line 164 of the bottom surface 110C in a direction that is parallel to and perpendicular to the outer contour line 164 of the bottom surface 110C.

[0158] The third straight line 152 is the portion of the outline of the virtual unfolded shape 162 that extends from the first straight line 150c on the bottom surface 110C.

[0159] The second curved line 153 is the portion of the outline of the virtual unfolded shape 162 that extends vertically from various positions of the first curved line 111c on the bottom surface 110C.

[0160] The fourth straight line 154 is the portion of the outline of the virtual unfolded shape 162 that extends from the second straight line 151c on the bottom surface 110C.

[0161] When viewing cross-sections in planes perpendicular to the outline 164 of the bottom surface 110C at various locations on the outline 164 of the bottom surface 110C, the shape of the portion of the raw material metal sheet 10A formed into the corner shape 124 is the same as the virtual unfolded shape 162, or is a shape that is further extended than the virtual unfolded shape 162 in a direction parallel to the bottom surface 110C and perpendicular to the outline 164 of the bottom surface 110C.

[0162] The length extending from the outline of the virtual unfolded shape 162 to the outline 163 of the raw material metal plate 10A at each cross-sectional position is defined as the excess material length α (mm). In other words, the excess material length α is the vertical distance from the outline of the virtual unfolded shape 162.

[0163] The junction of the first straight line 150c and the first curved line 111c is designated as point b1.

[0164] The junction of the second straight line 151c and the first curved line 111c is designated as point b2.

[0165] Let the line passing through point b1, parallel to the bottom surface 110C, and perpendicular to the first straight line 150c be the first normal line L1.

[0166] Let the line passing through point b2, parallel to the bottom surface 110C, and perpendicular to the second line 151c be the second normal line L2.

[0167] Let point O be the intersection of the first normal L1 and the second normal L2.

[0168] The side of the raw material metal plate 10A other than the bottom surface 110C and which does not include the second curvature line 153 relative to the first normal L1 is designated as the first edge 15.

[0169] The side of the raw material metal plate 10A other than the bottom surface 110C and which does not include the second curvature line 153 relative to the second normal line L2 is designated as the second side 16.

[0170] The blank corner 17 is defined as the area outside the bottom part 110C of the raw material metal plate 10A and between the first normal line L1 and the second normal line L2.

[0171] like Figure 15A and Figure 15BAs shown, the distance from the bottom surface 110C to the curved flange 143c in the direction perpendicular to the bottom surface 110C of the corner shape 124 is defined as the corner shape height h (mm).

[0172] like Figure 13 As shown, in the first edge 15 of the raw material metal plate 10A, when observing the remaining material length α along the first straight line 150c from the first normal L1 in the direction opposite to the blank corner 17, if the position on the outer line 163 of the raw material metal plate 10A where the remaining material length α first reaches its minimum value is within 3h from the first normal L1, then the position on the outer line 163 of the raw material metal plate 10A where the remaining material length α first reaches its minimum value from the first normal L1 is set as the remaining material standing position P1 (intersection) P1 of the first edge 15. If the remaining material length α does not reach its minimum value within 3h from the first normal L1, then the position on the outer line 163 of the raw material metal plate 10A where the remaining material length α first reaches its minimum value within 3h from the first normal L1 is set as the remaining material standing position P1 of the first edge 15.

[0173] The distance from the first normal L1 to the standing position P1 of the first edge 15 is set as C1, and the length of the remaining material at that position is set as α1 (mm).

[0174] like Figure 13 As shown, in the second side 16 of the raw material metal plate 10A, when observing the remaining material length α along the second straight line 151c in the direction opposite to the blank corner 17 from the second normal line L2, if the position on the outer line 163 of the raw material metal plate 10A where the remaining material length α first reaches its minimum value is within 3h from the second normal line L2, then the position on the outer line 163 of the raw material metal plate 10A where the remaining material length α first reaches its minimum value from the second normal line L2 is set as the remaining material standing position P2 (intersection point P2) of the second side 16. If the remaining material length α does not reach its minimum value within 3h from the second normal line L2, then the position on the outer line 163 of the raw material metal plate 10A where the remaining material length α first reaches its minimum value within 3h from the second normal line L2 is set as the remaining material standing position P2 of the second side 16.

[0175] Let C2 be the distance from the second normal L2 to the position P2 where the excess material is erected on the second side 16, and let α2 (mm) be the length of the excess material at that position.

[0176] The line that has been moved parallel to the first normal L1 by a length C1 toward the first side 15 is designated as line L11.

[0177] Let the line that has been moved parallel to the second normal L2 by a length C2 toward the second side 16 be line L21.

[0178] Let the intersection point P3 be the intersection point of the line that passes through intersection point P1 and is parallel to the first line 150c and the line that passes through intersection point P2 and is parallel to the second line 151c.

[0179] As defined above, in the portion of the first side 15 closer to the blank corner 17 than the straight line L11, and in the portions of the blank corner 17 and the second side 16 closer to the blank corner 17 than the straight line L21, the outline 163 of the raw material metal plate 10A is located on the opposite side of the bottom part 110C, i.e., on the outer side, than the broken line formed by line segments P1P3 and P3P2.

[0180] Furthermore, when the intersection points of the line passing through intersection point P3 and perpendicular to the line connecting intersection points O and P3, and the outline line 163 of the raw material metal plate 10A are defined as intersection points Q1 and Q2, and the length of line segment Q1Q2 is defined as length B (mm), and the length of line segment P1P2 is defined as length D (mm), the following conditions are met: 0 < α1 ≤ h (Equation 1) 0 < α2 ≤ h (Equation 2).

[0181] Further satisfy: 0.3D≤B (Equation 3).

[0182] This embodiment is a raw material metal sheet being formed into a metal sheet 10 having a corner shape 124 as described above.

[0183] According to this embodiment, a shape including the desired corner shape can be integrally molded without joints based on welding, bonding, etc. Therefore, it exhibits excellent formability and can suppress wrinkles and cracks.

[0184] Let C (mm) be the distance from line segment Q1Q2 to the point on the outermost line 163 of the raw material metal plate 10A between intersection point Q1 and intersection point Q2.

[0185] On the side opposite to the blank corner 17 relative to the first normal L1 of the first side 15 and on the side opposite to the blank corner 17 relative to the second normal L2 of the second side 16, the following can be satisfied: 0 < α < 3h (Equation 4).

[0186] It can also be further satisfied: 0.3D≤B≤1.5D (Equation 5) 0≤C≤2B (Equation 6).

[0187] As a result, it has better formability and can further suppress wrinkles and cracks.

[0188] (Battery tray) for Figure 10 The stamped metal sheet 10B shown in (b) is cut off as excess material for the product and then finished into the final product. For example, Figure 10 The battery tray 50 shown in (c) is finished into a product.

[0189] Reference Figures 14 to 15B The battery tray 50 involved in this embodiment will be described.

[0190] In this embodiment, the battery tray 50 is a steel plate with a tensile strength of 390 MPa or higher, made from raw material metal plate 10A.

[0191] The battery tray 50 is a shape that includes corner shape 124.

[0192] The corner shape 124 is composed of a bottom surface 110C, a first ridge 112c, a second ridge 113c, a first curved ridge 152c, a first longitudinal wall 125c, a second longitudinal wall 126c, a longitudinal wall ridge 121c, a third ridge 132c, a fourth ridge 133c, a second curved ridge 131c, a first flange portion 141c, a second flange portion 142c, and a curved flange portion 143c.

[0193] The bottom surface 110C is a shape that includes a first straight line 150c, a second straight line 151c, and a first curved line 111c connecting the first straight line 150c and the second straight line 151c as part of the outline.

[0194] The first ridge line 112c is connected to the bottom surface 110C via the first straight line 150c.

[0195] The second ridge line 113c is connected to the bottom surface 110C via the second straight line 151c.

[0196] The first curved ridge 152c is connected to the bottom surface 110C via the first curved ridge 111c and is also connected to the first ridge 112c and the second ridge 113c.

[0197] The first longitudinal wall 125c stands upright on the opposite side of the bottom surface 110C, connected to the first ridge line 112c.

[0198] The second longitudinal wall 126c stands upright on the opposite side of the bottom surface 110C, connected to the second ridge line 113c.

[0199] The longitudinal wall edge 121c stands on the opposite side of the bottom surface 110C, connected to the first curved edge 152c, and is connected to the first longitudinal wall 125c and the second longitudinal wall 126c.

[0200] The third ridge 132c is connected to the first longitudinal wall 125c on the opposite side of the first ridge 112c.

[0201] The fourth ridge 133c is connected to the second longitudinal wall 126c on the opposite side of the second ridge 113c.

[0202] The second curved ridge 131c is connected to the longitudinal wall ridge 121c on the opposite side of the first curved ridge 152c and connects the third ridge 132c with the fourth ridge 133c.

[0203] The first flange portion 141c is connected to the third ridge line 132c on the opposite side of the first longitudinal wall 125c. The second flange portion 142c is connected to the fourth ridge line 133c on the opposite side of the second longitudinal wall 126c.

[0204] The curved flange 143c is connected to the second curved ridge 131c on the opposite side of the longitudinal wall ridge 121c and connects the first flange 141c to the second flange 142c.

[0205] exist Figure 15A and Figure 15B The text is a jumbled mix of Chinese characters and symbols, making it impossible to translate coherently. It appears to be a collection of fragments from various sources, possibly related to news articles or reports. Figure 14 A schematic cross-sectional view of the battery tray 50 at various locations shown. Figure 15A Indicates that it has been passed Figure 14 A schematic cross-sectional view of the battery tray 50 at position A-A' (through the first longitudinal wall 125c). Figure 15B Indicates that it has been passed Figure 14 A schematic cross-sectional view of the battery tray 50 at the position of B-B' (through the second longitudinal wall 126c).

[0206] The distance from the bottom part 110B to the curved flange 143c in the direction perpendicular to the bottom part 110C of the corner shape 124c is defined as the height h (mm) of the corner shape.

[0207] When the radius of curvature of the longitudinal wall edge 121c is set to Rb, the angle between the bottom surface 110C and the first longitudinal wall 125c is set to E1 (°), and the angle between the bottom surface 110C and the second longitudinal wall 126c is set to E2 (°), the following conditions are met: 1≤h / Rb≤15 (Equation 7) 90°≤E1<105° (Equation 8) 90°≤E2<105° (Equation 9).

[0208] Angle E1 (°) is preferably 90°≤E1<95° or 92°≤E1≤100°. Angle E2 (°) is preferably 90°≤E2<95° or 92°≤E2≤100°.

[0209] also, Figure 14θ is the angle (°) formed by the first line 150c and the second line 151c. The angle θ is preferably 80°≤θ≤120°.

[0210] The curvature radius Rb of the corner shape height h and the longitudinal wall edge 121c is explained (Equation 7).

[0211] If the radius of curvature Rb is too small relative to the corner height h, it will be difficult to suppress the shrinkage flange even if the corner of the raw material metal plate 10A protrudes. Therefore, it is preferable that h / Rb ≤ 15. If the radius of curvature Rb becomes larger relative to the corner height h, the loading efficiency of the battery cells in the battery tray 50 decreases, so it is preferable that 1 ≤ h / Rb.

[0212] The angle E1 formed by the bottom surface 110C and the first longitudinal wall 125c, and the angle E2 formed by the bottom surface 110C and the second longitudinal wall 126c are explained (Equations 8 and 9).

[0213] If angles E1 and E2 are less than 90°, the longitudinal wall will be at a negative angle relative to the forming direction of the die during stamping, making deep drawing impossible. Furthermore, if angles E1 and E2 are too large, the battery cell loading efficiency of the battery tray will decrease. Therefore, angles E1 and E2 are preferably 90° or greater and less than 105°.

[0214] It is formed by stamping from a single raw material metal sheet 10A, and does not include any joints between the raw material metals. The raw material metal sheet 10A does not include any joints based on welding, bonding, etc.

[0215] When the thickness of the raw material metal plate 10A is set to t (mm), the radius of curvature of the first edge 112c is set to r1 (mm), the radius of curvature of the second edge 113c is set to r2 (mm), the radius of curvature of the third edge 132c is set to r3 (mm), and the radius of curvature of the fourth edge 133c is set to r4 (mm), the following conditions are met: 2.5t≤r1≤0.2h (Equation 10) 2.5t≤r²≤0.2h (Equation 11) 2.5t≤r3≤0.2h (Equation 12) 2.5t≤r4≤0.2h (Equation 13).

[0216] The radius of curvature r1 is preferably 3t ≤ r1 ≤ 0.1h. The radius of curvature r2 is preferably 3t ≤ r2 ≤ 0.1h. The radius of curvature r3 is preferably 3t ≤ r3 ≤ 0.1h. The radius of curvature r4 is preferably 3t ≤ r4 ≤ 0.1h.

[0217] If the radii of curvature r1, r2, r3, and r4 are too small, the flow resistance of the material at these ridges increases during stamping in high-strength raw material metal sheets. According to the present invention, cracks are also more likely to occur, making forming difficult. Therefore, the radii of curvature r1, r2, r3, and r4 are preferably 2.5 times or more the sheet thickness t. Furthermore, if the radii of curvature r1, r2, r3, and r4 are too large, the loading efficiency of the battery cells in the battery tray 50 decreases. Therefore, the radii of curvature r1, r2, r3, and r4 are preferably 0.2h or less.

[0218] According to this embodiment, it can be integrally molded into a shape including the desired corner shape, without any joints based on welding, bonding, etc. Therefore, it has excellent formability and can suppress wrinkles and cracks. Furthermore, the raw material metal plate 10A of the battery tray 50 in this embodiment is a steel plate with a tensile strength of 390 MPa or higher, thus it is lightweight and has excellent strength.

[0219] [Second Implementation] Reference Figure 16-18 The method for forming the metal sheet according to the second embodiment will be described. In the second embodiment, the same reference numerals are used for components that are the same as those in the first embodiment, and their descriptions are omitted; only the differences are described.

[0220] The forming method of the metal sheet (raw material metal sheet) 10a in this embodiment is a forming method of drawing the metal sheet 10a into a shape including a predetermined corner shape 124 using a mold device 1000 having a die 100, a punch 200 and a retainer 300.

[0221] like Figure 13 As shown, a straight line on the metal plate 10 that has been moved parallel to the first normal L1 towards the first side 15 by a distance of 0.5 times the length C1 is designated as line L12, and a straight line on the metal plate 10 that has been moved parallel to the second normal L2 towards the second side 16 by a distance of 0.5 times the length C2 is designated as line L22.

[0222] When the metal sheet 10 is arranged in the die assembly 1000 for stamping, draw beads 165 are provided on the die 100 and the holder 300 at one or both of the following locations: the area on the side opposite to the blank corner 17 of the first edge 15 of the metal sheet 10 relative to the straight line L12, and the area on the side opposite to the blank corner 17 of the second edge 16 relative to the straight line L22. However, draw beads 165 are not provided at the locations corresponding to the die 100 and the holder 300 of the first edge 15, the second edge 16, and the blank corner 17 between the straight lines L12 and L22 of the metal sheet 10. Furthermore, the region between the first normal line L1 and the straight line L12, and the region between the second normal line L2 and the straight line L22 are designated as part F. Draw beads 165 are not provided at the locations corresponding to part F, corresponding to the die 100 and the holder 300.

[0223] exist Figure 18 The diagram shows an example of a draw bead 165 provided on the holder 300 at a position indicated by the dashed line on the metal plate 10a. It also shows a case where draw beads 165 are provided on both the die 100 and the holder 300 in the area corresponding to the first edge 15 of the metal plate 10a, opposite to the blank corner 17 (as opposed to straight line L12), and the second edge 16, opposite to the blank corner 17 (as opposed to straight line L22). Figure 17 The diagram shows the corresponding positions of the draw beads 165 on the metal plate 10a when a die device 1000 with draw beads 165 is used.

[0224] By configuring the draw bead 165 in this way, the inflow resistance of the first flange portion 141c and the second flange portion 142c increases while the inflow rate decreases. As a result, the compression of the flange portions (F portions) on both sides of the curved flange portion 143c is mitigated. Consequently, although the inflow of material into the first flange portion 141c and the second flange portion 142c is slightly suppressed, the material inflow into the corner portion that leads to crack formation is further improved.

[0225] (Mold assembly) Reference Figure 16 An example of a mold device that can be formed in the first and second embodiments will be described.

[0226] For example, such as Figure 16 As shown, the mold assembly 1000 includes a die 100, a retainer 300, and a punch 200.

[0227] The die 100, retainer 300 and punch 200 are arranged opposite each other in this order.

[0228] The punch 200 has a protrusion 223 on the surface opposite to the retainer 300.

[0229] The die 100 has a recess 123 on the surface opposite to the retainer 300. By moving the die 100 and the punch 200 relative to each other in the approaching direction P (the stamping direction), the protrusion 223 of the punch 200 is pressed into the recess 123 of the die 100.

[0230] The retainer 300 has a punch hole 323. The retainer 300 and the punch 200 move relative to each other in a direction of approach P, thereby the protrusion 223 of the punch 200 passes through the punch hole 323 of the retainer 300.

[0231] The raw material metal sheet 10A, which is the workpiece, is disposed between the punch 200 and the retainer 300. In this state, the die 100 and the punch 200 move relative to each other in the stamping direction, thereby causing the raw material metal sheet 10A to be plastically deformed.

[0232] The die 100, punch 200, and retainer 300 can each be composed of a single component or can each be composed of a segmented die. In addition, the die assembly 1000 may also include dies other than these dies.

[0233] In the above embodiments, the battery tray 50 can be a final product or an intermediate product for further processing (stamping, cutting, bending, welding, heating and cooling, plating, painting) to produce a final product.

[0234] Example The embodiments of the present invention will be described below.

[0235] First, Examples 1 to 12 will be described. Examples 4, 10, and 12 are embodiments of the present invention, while Examples 1, 2, 3, 5, 6, 7, 8, 9, and 11 are comparative examples used to illustrate the effects of the present invention.

[0236] Figure 19 This represents a general outline of the shape of the final product in Examples 1-12. Furthermore, the final product refers to the processed raw material metal sheet obtained by stamping and forming it into a shaped form, followed by further trimming of its outer periphery.

[0237] The bottom part 110d is approximately rectangular in shape with a width We and a length Le. The bottom part 110d is connected to the longitudinal wall 125d and the longitudinal wall edge 121d via the punch shoulder edge 112d. The longitudinal wall 125d and the longitudinal wall edge 121d form a deep-drawn square tube shape connected to the flange 141d via the die shoulder edge 132d, and it has a shape with four corners.

[0238] Regarding the shapes of each corner, if compared Figure 19 and Figure 12Then, the bottom surface 110d is equivalent to the bottom surface 110C, the longitudinal wall 125d is equivalent to the first longitudinal wall 125c and the second longitudinal wall 126c, the longitudinal wall edge 121d is equivalent to the longitudinal wall edge 121c, and the flange portion 141d is equivalent to the first flange portion 141c, the second flange portion 142c, and the curved flange portion 143c. Furthermore, the punch shoulder edge 112d is equivalent to the first edge 112c, the second edge 113c, and the first curved edge 152c, and the punch die shoulder edge 132d is equivalent to the third edge 132c, the fourth edge 133c, and the second curved edge 131c. Here, the radius of curvature of the short side of the straight portion of the punch shoulder edge 112d is set as the short side punch shoulder edge radius rep1. The radius of curvature of the long side of the straight portion of the punch shoulder edge is set as the long side punch shoulder edge radius rep2. Let the radius of curvature of the short side of the straight section of the die shoulder edge 132d be the short side die shoulder edge radius red1. Let the radius of curvature of the long side of the straight section of the die shoulder edge 132d be the long side die shoulder edge radius red2. Let the radius of curvature of the longitudinal wall edge 121d be reb. If comparing... Figures 14 to 15B and Figure 12 Then reb is equivalent to Figure 13 The radius of curvature Rb of the longitudinal wall edge 121c. rep1 and rep2 are equivalent to Figure 14 r1 and r2. red1 and red2 are equivalent to Figure 14 r3 and r4. Additionally, the vertical distance from the bottom surface 110d to the flange 141d is defined as the height He. Height He is equivalent to... Figure 14 The corner shape height h. Let θe be the angle formed by the long side and short side of the straight section of the bottom surface 110d. θe is equivalent to... Figure 13 θ.

[0239] In Examples 1-6 and Example 8, the width We, length Le, height He, longitudinal wall edge radius (radius of curvature) Rb, short side punch shoulder edge radius rep1, long side punch shoulder edge radius rep2, short side die shoulder edge radius red, and long side die shoulder edge radius red2 are the values ​​shown in Shape 1 of Table 1, and θe is 90°, the angle of the longitudinal wall relative to the bottom surface (equivalent to...) Figure 15A and Figure 15B The shape of the final product is defined by E1 and E2 with a 92° angle and a flange width of 30 mm.

[0240] In Example 7, the width We of the bottom surface, the length Le of the bottom surface, the height He, the radius Rb of the longitudinal wall edge, the radius rep1 of the short side punch shoulder edge, the radius rep2 of the long side punch shoulder edge, the radius red of the short side punch shoulder edge, and the radius red2 of the long side punch shoulder edge are the values ​​shown in Shape 3 in Table 1, and the shape with θe of 90°, the angle of the longitudinal wall relative to the bottom surface of 92°, and the width of the flange of 30mm is taken as the shape of the final product.

[0241] In Examples 9-12, the width We of the bottom surface, the length Le of the bottom surface, the height He, the radius Rb of the longitudinal wall edge, the radius rep1 of the short side punch shoulder edge, the radius rep2 of the long side punch shoulder edge, the radius red of the short side punch shoulder edge, and the radius red2 of the long side punch shoulder edge are the values ​​shown in Shape 2 of Table 1, and the shape with θe of 90°, the angle of the longitudinal wall relative to the bottom surface of 92°, and the width of the flange of 30mm is taken as the shape of the final product.

[0242] [Table 1] As raw material metal plates, Examples 1 and 2 used steel plates with a tensile strength of 270 MPa, a thickness of 1 mm, and an elongation EL of 49% (270 MPa material); Examples 3-8 used steel plates with a tensile strength of 590 MPa, a thickness of 1 mm, and an elongation EL of 30% (590 MPa material); Examples 9-11 used steel plates with a tensile strength of 980 MPa, a thickness of 1 mm, and an elongation EL of 20% (980 MPa material); and Example 12 used aluminum plates with a tensile strength of 240 MPa, a thickness of 1 mm, and an elongation EL of 22%.

[0243] In addition, the shape of the raw material metal plate was set in Example 1 as follows: Figure 20A The shape of the rectangle shown is set to be only in embodiments 2 and 3. Figure 20B The corner shown (will) Figure 13 The shape between the first normal L1 and the second normal L2 is designed as a protruding corner 17 of the billet, which is set in Examples 4 and 7. Figure 20C The corner shown and its surrounding area (including) Figure 13 The blank corner portion 17 is a shape that protrudes from the straight line L11 of the first side portion 15 to the second side portion 16 (between the straight line L21 and the blank corner portion 17). In embodiment 5, it is set to be relative to Figure 20C The shape of the raw material steel plate is such that the overall length is increased by 500mm, and the protruding part also elongates as the overall length is increased. In Example 6, it is set to be relative to... Figure 20C The shape of the protrusion is adjusted by shortening the central protrusion height, increasing the protrusion height at the end of the protrusion, and reducing... Figure 13The length B of line segment Q1Q2 is increased, and the shape of the length D of line segment P1P2 is increased. In Example 8, the raw material metal plate becomes relative to Figure 20C The shape of the protruding part is changed by decreasing the length D of line segment P1P2 and increasing the length B of line segment Q1Q2, where length B is greater than length D, i.e., the width of the protruding front end is wider than the root. In embodiments 9-12, the raw material metal plate is set as... Figure 20D The corner and the protruding shape around it are shown.

[0244] All examples used Figure 21 The die 1000X, as shown, consists of a punch 200X, a die 100X, and a retainer 300X. In a deep drawing process, the raw material metal sheet is pressed against the die 100X by pressure applied around its periphery by the retainer 300X, and then the central portion of the raw material metal sheet is pressed from the retainer 300X side towards the die 100X side by the punch 200X. Furthermore, in each embodiment, the shape of the die is a shape that matches the formed shape. Figure 21 This section provides an overview of the mold's structure and configuration; the detailed mold shape varies depending on the specific embodiment.

[0245] In addition, in Examples 1 to 9 and 12, no draw beads were provided on the mold, while in Examples 10 and 11, draw beads were provided on the retainer and the punch in the mold. Figure 22A This indicates the position of the drawbeads on the retainer in Embodiment 10. Furthermore, for the die in Embodiment 10, pairs of drawbeads are also provided at locations corresponding to the drawbead positions on the retainer. In Embodiment 11, in... Figure 22B The holder shown is provided with draw beads at the same position as in Embodiment 10. For the die, pairs of draw beads are also provided at the positions that are paired with the draw beads on the holder.

[0246] The length of the drawbar in Example 10 is... Figure 13 The first side 15 is located in the area opposite to the blank corner 17 compared to the straight line L12, and the second side 16 is located in the area opposite to the blank corner 17 compared to the straight line L22. On the other hand, the draw beads of Embodiment 11 are longer than those of Embodiment 10. That is, the draw beads of Embodiment 11 are not only arranged in... Figure 13 The first side portion 15 is located in the range opposite to the blank corner portion 17 compared to the straight line L12, and the second side portion 16 is located in the range opposite to the blank corner portion 17 compared to the straight line L22. It is also disposed in the range including the range of the first side portion 15 being closer to the blank corner portion 17 than the straight line L12 and the range of the second side portion 16 being closer to the blank corner portion 17 than the straight line L22.

[0247] Table 2 shows the main conditions and whether or not cracks were generated in Examples 1-12.

[0248] [Table 2] In Example 1, by Figure 20A The rectangular shape of the 270MPa material shown was used to form the raw material metal sheet, but due to insufficient material flow caused by the shrinkage flange, cracks occurred. In contrast, in Example 2, the same 270MPa material was used to form... Figure 20B The raw material metal sheet shown has a protrusion, which can suppress shrinkage flanges and increase material flow, thus suppressing cracking during molding.

[0249] However, in Example 3, under the same conditions as Example 2, but with the raw material metal sheet changed to a 590MPa material with an elongation EL lower than that of the 270MPa material, the material flow became insufficient, resulting in cracks at the longitudinal wall edges. This is because the protruding portion of shape 2 is only at the corners ( Figure 13 The blank corner 17 between the first normal L1 and the second normal L2 in the blank is not sufficiently improved in terms of material flow. Therefore, under the same conditions as in Example 3, the shape of the raw material metal sheet is made such that the corner and its surrounding area (including...) Figure 13 The blank corner 17 protrudes between the straight line L11 of the first side 15 and the straight line L21 of the second side 16. Figure 20C In Example 4, the material flow was improved compared to Example 3. Therefore, in Example 4, even a 590MPa material with a lower elongation EL than the 270MPa material was able to be molded with crack suppression.

[0250] In Example 5, the raw material metal plate was increased compared to Example 4, so α1 became 3h or more. Therefore, a significant portion of the material in the bent flange portion was further displaced from the inflow direction of the protrusion. As a result, the shrinkage flange suppression effect of the protrusion decreased, material inflow reduced, and cracks formed at the longitudinal wall ridge.

[0251] In Example 6, compared to Example 4, the shape of the protruding portion was changed, and the length D of line segment P1P2 was increased while the length B of line segment Q1Q2 was decreased, so that B became less than 0.3D. Therefore, the shape became close to a rectangle. As a result, the shrinkage flange suppression effect decreased, material inflow was suppressed, and cracks were generated at the longitudinal wall ridges.

[0252] In Example 7, the radii of the short-side die shoulder edge, red1, and the radii of the long-side die shoulder edge, red2, were reduced to 2.4 mm compared to Example 4. With the die shoulder edge radii decreasing, red1(r2) and red2(r2) are less than 2.5t, thus increasing the inflow resistance at the edge portion during forming. As a result, material inflow decreases, and cracks occur at the longitudinal wall edge portion.

[0253] In Example 8, compared to Example 4, the shape of the protruding portion is changed, and the length D of line segment P1P2 is reduced, while the length B of line segment Q1Q2 is increased, with B becoming 1.5 or more. As a result, the width of the front end of the protruding portion of the angle becomes wider than the width of the root, thus creating a concave shape on the side of the protruding portion. Consequently, deformation concentrates at the end of the concave portion on this side, resulting in cracks.

[0254] In Example 9, compared to Example 4, the following was used Figure 20D The shape shown is a raw material steel plate of 980MPa material. Compared with 590MPa material, 980MPa material has a lower elongation (EL), so even in shapes with protrusions, cracks occur at the longitudinal wall edges.

[0255] Compared to Example 9, in Example 10, in the mold... Figure 13 Draw beads are provided on the first side 15, in the area opposite to the blank corner 17 compared to straight line L12, and on the second side 16, in the area opposite to the blank corner 17 compared to straight line L22. This mitigates compression of the flange portions (F portions) on both sides of the bent flange portion. As a result, material flow is increased, and even with a low elongation EL of 980 MPa, cracking can be suppressed during forming.

[0256] However, in Example 11, the drawbars were increased compared to Example 10. In Example 11, the drawbars were not only arranged in... Figure 13 The first side 15 is located in the area opposite to the blank corner 17 compared to the straight line L12, and the second side 16 is located in the area opposite to the blank corner 17 compared to the straight line L22. It is also disposed within the area including the area of ​​the first side 15 closer to the blank corner 17 than the straight line L12 and the area of ​​the second side 16 closer to the protrusion 13 than the straight line L22. Therefore, the material flow resistance at the flange portions (F portions) on both sides of the curved flange portion increases. As a result, in Embodiment 11, the material flow is reduced compared to Embodiment 10, thus cracks are generated at the longitudinal wall ridge portion.

[0257] In Example 12, the type of raw material metal sheet is set to aluminum sheet, as in Example 9. Therefore, in Example 12, according to the technology of the present invention, even if the raw material metal sheet is a material other than steel sheet, cracking can be suppressed during molding.

[0258] Next, Examples 13 to 16 will be described.

[0259] The shape of the final product of Example 13 is shown in Figure 23A The shape of the final product of Example 14 is shown in Figure 23B Example 13 uses a steel plate with a tensile strength of 590 MPa, a thickness of 1.2 mm, and an elongation EL of 30% for forming. Example 14 uses a steel plate with a tensile strength of 590 MPa, a thickness of 0.8 mm, and an elongation EL of 30% for forming. Thus, according to the technology of the present invention, even if the bottom surface shape is not rectangular but trapezoidal or a shape other than a quadrilateral such as an octagon, it can be formed well.

[0260] The shape of the final product of Example 15 is shown in Figure 23C Example 15 uses a steel plate with a tensile strength of 590 MPa, a thickness of 1.6 mm, and an elongation EL of 30% for forming. Thus, according to the technology of the present invention, even shapes that include corners but whose longitudinal walls and flanges are not continuous around the circumference can be formed well.

[0261] In Example 16, a steel plate with a tensile strength of 590 MPa, a thickness of 1.2 mm, and an elongation EL of 30% was pre-processed into... Figure 24A The shape shown is used as the raw material metal sheet, and is formed by the technology of this invention. Figure 24B The shape shown. Thus, in this invention, a pre-processed metal sheet can be used as a raw material metal sheet.

[0262] Industrial availability According to the present invention, a method for forming a metal sheet, a raw material metal sheet, and a battery tray can be provided for integrally forming a shape using a high-strength metal sheet, comprising a corner shape with a small radius of curvature of each edge connecting the longitudinal wall, the bottom surface, and the flange.

[0263] Explanation of symbols 10 Metal Plates 10A, 10a, 10V1, 10V2, 10V3, 10V4 raw material metal plates 10B (stamped) metal sheet 10C (trimmed and finished) metal sheet 11 corner 13. Protrusion 15 First side 16 Second side 17. Corner of billet 50 Battery Tray 100 stamping die Bottom surface of 110A, 110B, and 110C 111c First Curve 112c First edge line 113c Second edge line 121c Longitudinal wall edge 124 Corner Shape 125c First longitudinal wall 126c Second longitudinal wall 131c Second Curved Edge 132c Third edge line 133c Fourth edge 141c First flange portion 142c Second flange 143c, 143V1, 143V2, 143V3 curved flange 144V1, 144V2, 144V3 corner section 150c First straight line 151c Second straight line 152 Third straight line 152c First Curved Edge 153 Second Curve 154 Fourth straight line 162 Virtual unfolded shape 162E End of the final product 163 (Outline of raw material metal sheet) 164 (Bottom surface) outline 165 Tie bars 200 punch 300 retainer 1000 Mold Device

Claims

1. A method for forming a metal sheet, comprising processing the metal sheet into a shape including corners, characterized in that, The corner shape includes: The bottom surface has a shape that includes, as part of the outline, a first straight line, a second straight line, and a first curved line connecting the first straight line and the second straight line; The first ridge line is connected to the bottom surface through the first straight line; The second ridge line is connected to the bottom surface through the second straight line; A first curved ridge line is connected to the bottom surface through the first curved line and is also connected to the first ridge line and the second ridge line; The first longitudinal wall rises on the opposite side of the bottom surface, connected to the first ridge line; The second longitudinal wall rises on the opposite side of the bottom surface, connected to the second ridge line; The longitudinal wall edge rises on the opposite side of the bottom surface, connected to the first curved edge, and is connected to the first longitudinal wall and the second longitudinal wall; The third ridge line is connected to the first longitudinal wall on the opposite side of the first ridge line; The fourth ridge line is connected to the second longitudinal wall on the opposite side of the second ridge line; The second curved edge line connects to the longitudinal wall edge line on the opposite side of the first curved edge line and connects the third edge line to the fourth edge line; The first flange is connected to the third ridge on the opposite side of the first longitudinal wall and extends substantially horizontally; The second flange, on the opposite side of the second longitudinal wall, connects to the fourth ridge and extends substantially horizontally; and A curved flange portion, connected to the second curved ridge on the opposite side of the longitudinal wall ridge, extends substantially horizontally and connects the first flange portion and the second flange portion. In the molding method, When observing a cross-section of the corner shape in a plane perpendicular to the outline of the bottom surface at various positions on the outline of the bottom surface, which is formed by the first straight line, the second straight line, and the first curved line, the length of the cross-section from the outline of the bottom surface to the end of the product is defined as the outer length of the bottom surface at each position of the outline of the bottom surface. The shape at each position on the outline of the bottom surface, in a direction parallel to and perpendicular to the outline of the bottom surface, extending the outer length of the bottom surface at each position on the outline of the bottom surface, is defined as a virtual unfolded shape. The portion of the outline of the virtual unfolded shape that extends from the first straight line on the bottom surface is designated as the third straight line. The portion of the outline of the virtual unfolded shape that extends from the first curved line on the bottom surface is designated as the second curved line, and the portion of the outline of the virtual unfolded shape that extends from the second straight line on the bottom surface is designated as the fourth straight line. In this case, the shape of the portion of the raw material metal sheet including the corner shape is: when viewed at various positions on the outline of the bottom surface in a cross-section in a plane perpendicular to the outline of the bottom surface, it is the same as the virtual unfolded shape or extends further than the virtual unfolded shape in a direction parallel to and perpendicular to the outline of the bottom surface. The length of the excess material α is defined as the length from the outline of the virtual unfolded shape to the outline of the raw material metal plate at each cross-sectional position. Furthermore, the junction of the first straight line and the first curved line is designated as point b1, and the junction of the second straight line and the first curved line is designated as point b2. Let the line passing through point b1, parallel to the bottom surface, and perpendicular to the first straight line be designated as the first normal line L1; let the line passing through point b2, parallel to the bottom surface, and perpendicular to the second straight line be designated as the second normal line L2; and let the intersection of the first normal line L1 and the second normal line L2 be designated as point O. The side of the raw material metal plate outside the bottom surface and that does not include the second curvature line relative to the first normal L1 is designated as the first edge; the side of the raw material metal plate outside the bottom surface and that does not include the second curvature line relative to the second normal L2 is designated as the second edge; and the area between the first normal L1 and the second normal L2 outside the bottom surface of the raw material metal plate is designated as the blank corner. The distance from the bottom surface to the curved flange in the direction perpendicular to the bottom surface of the corner shape is defined as the height h of the corner shape. When observing the remaining material length α along the first straight line from the first normal L1 in the direction opposite to the corner of the billet at the first edge of the raw material metal plate, if the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value is within 3h from the first normal L1, then the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value from the first normal L1 is set as the remaining material standing position of the first edge. If no minimum value is reached within 3h from the first normal L1, then the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value within 3h from the first normal L1 is set as the remaining material standing position of the first edge. The distance from the first normal L1 to the remaining material standing position of the first edge is set as C1, and the remaining material length at that position is set as α1. When observing the remaining material length α along the second straight line from the second normal L2 in the direction opposite to the corner of the billet at the second edge of the raw material metal plate, if the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value is within 3h from the second normal L2, then the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value from the second normal L2 is set as the remaining material standing position of the second edge. If it does not reach its minimum value within 3h from the second normal L2, then the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value within 3h from the second normal L2 is set as the remaining material standing position of the second edge. The distance from the second normal L2 to this remaining material standing position of the second edge is set as C2, and the remaining material length at this position is set as α2. The intersection point P1 is defined as the point where the straight line L11, which has been moved parallel to the first normal L1 towards the first edge by a length C1, intersects the outline of the raw material metal plate. The intersection point P2 is defined as the point where the straight line L21, which has been moved parallel to the second normal L2 towards the second edge by a length C2, intersects the outline of the raw material metal plate. Let the intersection point P3 be the line that passes through the intersection point P1 and is parallel to the first line, and the line that passes through the intersection point P2 and is parallel to the second line. In this case, in the portion of the first side closer to the corner of the billet than the straight line L11, and in the portion of the billet corner and the second side closer to the corner of the billet than the straight line L21, the outline of the raw material metal plate is positioned on the opposite side (outer side) of the bottom surface than the broken line formed by line segments P1P3 and P3P2. Furthermore, when the intersection points of the line passing through intersection point P3 and perpendicular to the line connecting intersection points O and P3 with the outline of the raw material metal plate are defined as intersection points Q1 and Q2, and the length of line segment Q1Q2 is defined as length B, and the length of line segment P1P2 is defined as length D, the following conditions are met: 0 < α1 ≤ h (Equation 1) 0 < α² ≤ h (Equation 2), Further satisfy: 0.3D≤B (Equation 3).

2. The method for forming a metal sheet according to claim 1, characterized in that, The forming method includes a stamping process and a finishing process. Let C be the distance from the line segment Q1Q2 to the point on the outer contour line of the raw material metal plate between the intersection points Q1 and Q2 that is furthest away. On the side of the first edge opposite to the corner of the billet relative to the first normal L1 and on the side of the second edge opposite to the corner of the billet relative to the second normal L2, the following conditions are met: 0 < α < 3h (Equation 4), Further satisfy: 0.3D≤B≤1.5D (Equation 5) 0≤C≤2B (Equation 6).

3. A raw material metal sheet, which is a raw material metal sheet in the process of forming a metal sheet into a shape including corner shapes, characterized in that, The corner shape includes: The bottom surface has a shape that includes, as part of the outline, a first straight line, a second straight line, and a first curved line connecting the first straight line and the second straight line; The first ridge line is connected to the bottom surface through the first straight line; The second ridge line is connected to the bottom surface through the second straight line; A first curved ridge line is connected to the bottom surface through the first curved line and is also connected to the first ridge line and the second ridge line; The first longitudinal wall rises on the opposite side of the bottom surface, connected to the first ridge line; The second longitudinal wall rises on the opposite side of the bottom surface, connected to the second ridge line; The longitudinal wall edge rises on the opposite side of the bottom surface, connected to the first curved edge, and is connected to the first longitudinal wall and the second longitudinal wall; The third ridge line is connected to the first longitudinal wall on the opposite side of the first ridge line; The fourth ridge line is connected to the second longitudinal wall on the opposite side of the second ridge line; The second curved edge line connects to the longitudinal wall edge line on the opposite side of the first curved edge line and connects the third edge line to the fourth edge line; The first flange is connected to the third ridge on the opposite side of the first longitudinal wall and extends substantially horizontally; The second flange, on the opposite side of the second longitudinal wall, connects to the fourth ridge and extends substantially horizontally; and A curved flange portion, connected to the second curved ridge on the opposite side of the longitudinal wall ridge, extends substantially horizontally and connects the first flange portion and the second flange portion. In the raw material metal plate, When observing a cross-section of the corner shape in a plane perpendicular to the outline of the bottom surface at various positions on the outline of the bottom surface, which is formed by the first straight line, the second straight line, and the first curved line, the length of the cross-section from the outline of the bottom surface to the end of the product is set as the outer length of the bottom surface at each position of the outline of the bottom surface. The shape at each position on the outline of the bottom surface, in a direction parallel to and perpendicular to the outline of the bottom surface, extending the outer length of the bottom surface at each position on the outline of the bottom surface, is defined as a virtual unfolded shape. The portion of the outline of the virtual unfolded shape that extends from the first straight line on the bottom surface is designated as the third straight line. The portion of the outline of the virtual unfolded shape that extends from the first curved line on the bottom surface is designated as the second curved line, and the portion of the outline of the virtual unfolded shape that extends from the second straight line on the bottom surface is designated as the fourth straight line. In this case, the shape of the corner portion of the raw material metal sheet is: when viewed from various positions on the outline of the bottom surface, in a cross-section of a plane perpendicular to the outline of the bottom surface, it is the same as the virtual unfolded shape or extends further than the virtual unfolded shape in a direction parallel to and perpendicular to the outline of the bottom surface. The length of the excess material α is defined as the length from the outline of the virtual unfolded shape to the outline of the raw material metal plate at each cross-sectional position. Furthermore, the junction of the first straight line and the first curved line is designated as point b1, and the junction of the second straight line and the first curved line is designated as point b2. Let the line passing through point b1, parallel to the bottom surface, and perpendicular to the first straight line be designated as the first normal line L1; let the line passing through point b2, parallel to the bottom surface, and perpendicular to the second straight line be designated as the second normal line L2; and let the intersection of the first normal line L1 and the second normal line L2 be designated as point O. The side of the raw material metal plate outside the bottom surface and that does not include the second curvature line relative to the first normal L1 is designated as the first edge; the side of the raw material metal plate outside the bottom surface and that does not include the second curvature line relative to the second normal L2 is designated as the second edge; and the area between the first normal L1 and the second normal L2 outside the bottom surface of the raw material metal plate is designated as the blank corner. The distance from the bottom surface to the curved flange in the direction perpendicular to the bottom surface of the corner shape is defined as the height h of the corner shape. When observing the remaining material length α along the first straight line from the first normal L1 in the direction opposite to the corner of the billet at the first edge of the raw material metal plate, if the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value is within 3h from the first normal L1, then the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value from the first normal L1 is set as the remaining material standing position of the first edge. If no minimum value is reached within 3h from the first normal L1, then the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value within 3h from the first normal L1 is set as the remaining material standing position of the first edge. The distance from the first normal L1 to the remaining material standing position of the first edge is set as C1, and the remaining material length at that position is set as α1. When observing the remaining material length α along the second straight line from the second normal L2 in the direction opposite to the corner of the billet at the second edge of the raw material metal plate, if the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value is within 3h from the second normal L2, then the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value from the second normal L2 is set as the remaining material standing position of the second edge. If it does not reach its minimum value within 3h from the second normal L2, then the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value within 3h from the second normal L2 is set as the remaining material standing position of the second edge. The distance from the second normal L2 to this remaining material standing position of the second edge is set as C2, and the remaining material length at this position is set as α2. The intersection point P1 is defined as the point where the straight line L11, which has been moved parallel to the first normal L1 towards the first edge by a length C1, intersects the outline of the raw material metal plate. The intersection point P2 is defined as the point where the straight line L21, which has been moved parallel to the second normal L2 towards the second edge by a length C2, intersects the outline of the raw material metal plate. Let the intersection point P3 be the line that passes through the intersection point P1 and is parallel to the first line, and the line that passes through the intersection point P2 and is parallel to the second line. In this case, in the portion of the first side closer to the corner of the billet than the straight line L11, and in the portion of the billet corner and the second side closer to the corner of the billet than the straight line L21, the outline of the raw material metal plate is positioned on the opposite side (outer side) of the bottom surface than the broken line formed by line segments P1P3 and P3P2. Furthermore, when the intersection points of the line passing through intersection point P3 and perpendicular to the line connecting intersection points O and P3 with the outline of the raw material metal plate are defined as intersection points Q1 and Q2, and the length of line segment Q1Q2 is defined as length B, and the length of line segment P1P2 is defined as length D, the following conditions are met: 0 < α1 ≤ h (Equation 1) 0 < α² ≤ h (Equation 2), Further satisfy: 0.3D≤B (Equation 3).

4. The raw material metal plate according to claim 3, characterized in that, Let C be the distance from the line segment Q1Q2 to the point on the outer contour line of the raw material metal plate between the intersection points Q1 and Q2 that is furthest away. On the side of the first edge opposite to the corner of the billet relative to the first normal L1 and on the side of the second edge opposite to the corner of the billet relative to the second normal L2, the following conditions are met: 0 < α < 3h (Equation 4), Further satisfy: 0.3D≤B≤1.5D (Equation 5) 0≤C≤2B (Equation 6).

5. The method for forming a metal sheet according to claim 1 or 2, characterized in that, A die-drawing device with a die, a punch, and a retainer is used to draw a sheet metal into a shape that includes corners. The corner shape includes: The bottom surface, which is shaped as part of the outline, includes a first straight line, a second straight line, and a first curved line connecting the first straight line and the second straight line; The first ridge line is connected to the bottom surface through the first straight line; The second ridge line is connected to the bottom surface through the second straight line; A first curved ridge line is connected to the bottom surface through the first curved line and is also connected to the first ridge line and the second ridge line; The first longitudinal wall rises on the opposite side of the bottom surface, connected to the first ridge line; The second longitudinal wall rises on the opposite side of the bottom surface, connected to the second ridge line; The longitudinal wall edge rises on the opposite side of the bottom surface, connected to the first curved edge, and is connected to the first longitudinal wall and the second longitudinal wall; The third ridge line is connected to the first longitudinal wall on the opposite side of the first ridge line; The fourth ridge line is connected to the second longitudinal wall on the opposite side of the second ridge line; The second curved edge line connects to the longitudinal wall edge line on the opposite side of the first curved edge line and connects the third edge line to the fourth edge line; The first flange is connected to the third ridge on the opposite side of the first longitudinal wall and extends substantially horizontally; The second flange, on the opposite side of the second longitudinal wall, connects to the fourth ridge and extends substantially horizontally; and A curved flange portion, connected to the second curved ridge on the opposite side of the longitudinal wall ridge, extends substantially horizontally and connects the first flange portion and the second flange portion. In the molding method, When observing a cross-section of the corner shape in a plane perpendicular to the outline of the bottom surface at various positions on the outline of the bottom surface, which is formed by the first straight line, the second straight line, and the first curved line, the length of the cross-section from the outline of the bottom surface to the end of the product is defined as the outer length of the bottom surface at each position of the outline of the bottom surface. The shape at each position on the outline of the bottom surface, in a direction parallel to and perpendicular to the outline of the bottom surface, extending the outer length of the bottom surface at each position on the outline of the bottom surface, is defined as a virtual unfolded shape. The portion of the outline of the virtual unfolded shape that extends from the first straight line on the bottom surface is designated as the third straight line. The portion of the outline of the virtual unfolded shape that extends from the first curved line on the bottom surface is designated as the second curved line, and the portion of the outline of the virtual unfolded shape that extends from the second straight line on the bottom surface is designated as the fourth straight line. In this case, the shape of the corner portion of the raw material metal sheet is: when viewed from various positions on the outline of the bottom surface, in a cross-section of a plane perpendicular to the outline of the bottom surface, it is the same as the virtual unfolded shape or extends further than the virtual unfolded shape in a direction parallel to and perpendicular to the outline of the bottom surface. The length of the excess material α is defined as the length from the outline of the virtual unfolded shape to the outline of the raw material metal plate at each cross-sectional position. Furthermore, the junction of the first straight line and the first curved line is designated as point b1, and the junction of the second straight line and the first curved line is designated as point b2. Let the line passing through point b1, parallel to the bottom surface, and perpendicular to the first straight line be designated as the first normal line L1; let the line passing through point b2, parallel to the bottom surface, and perpendicular to the second straight line be designated as the second normal line L2; and let the intersection of the first normal line L1 and the second normal line L2 be designated as point O. The side of the raw material metal plate outside the bottom surface and that does not include the second curvature line relative to the first normal L1 is designated as the first edge; the side of the raw material metal plate outside the bottom surface and that does not include the second curvature line relative to the second normal L2 is designated as the second edge; and the area between the first normal L1 and the second normal L2 outside the bottom surface of the raw material metal plate is designated as the blank corner. The distance from the bottom surface to the curved flange in the direction perpendicular to the bottom surface of the corner shape is defined as the height h of the corner shape. When observing the remaining material length α along the first straight line from the first normal L1 in the direction opposite to the corner of the billet at the first edge of the raw material metal plate, if the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value is within 3h from the first normal L1, then the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value from the first normal L1 is set as the remaining material standing position of the first edge. If no minimum value is reached within 3h from the first normal L1, then the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value within 3h from the first normal L1 is set as the remaining material standing position of the first edge. The distance from the first normal L1 to the remaining material standing position of the first edge is set as C1. When observing the remaining material length α along the second straight line from the second normal L2 in the direction opposite to the corner of the billet at the second edge of the raw material metal plate, if the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value is within 3h from the second normal L2, then the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value from the second normal L2 is set as the remaining material standing position of the second edge. If it does not reach its minimum value within 3h from the second normal L2, then the position on the outer line of the raw material metal plate where the remaining material length α first reaches its minimum value within 3h from the second normal L2 is set as the remaining material standing position of the second edge. The distance from the second normal L2 to this remaining material standing position of the second edge is set as C2, and the remaining material length at this position is set as α2. Let the straight line on the metal plate be a line that has been moved parallel to the first normal L1 and toward the first edge by a distance of 0.5 times the length C1, and be designated as line L12. Let the straight line on the metal plate that has been moved parallel to the second normal L2 and toward the second edge by a distance of 0.5 times the length C2 be designated as line L22. Draw beads are provided at one or both of the following locations: the first side of the die and the holder, which is located on the opposite side of the blank corner relative to the straight line L12, and the second side, which is located on the opposite side of the blank corner relative to the straight line L22. Draw beads are not provided at the locations corresponding to the die and the holder at the first side, the second side, and the blank corner between the straight lines L12 and L22.

6. The method for forming a metal sheet according to claim 1 or 2, characterized in that, The raw material metal plate is a steel plate with a tensile strength of 390MPa or higher.

7. The raw material metal plate according to claim 3 or 4, characterized in that, The raw material metal plate is a steel plate with a tensile strength of 390MPa or higher.

8. A battery tray, wherein the raw material metal plate is a steel plate with a tensile strength of 390 MPa or higher, and the shape includes a corner shape, characterized in that... The corner shape includes: The bottom surface has a shape that includes, as part of the outline, a first straight line, a second straight line, and a first curved line connecting the first straight line and the second straight line; The first ridge line is connected to the bottom surface through the first straight line; The second ridge line is connected to the bottom surface through the second straight line; A first curved ridge line is connected to the bottom surface through the first curved line and is also connected to the first ridge line and the second ridge line; The first longitudinal wall rises on the opposite side of the bottom surface of the first ridge; The second longitudinal wall rises on the opposite side of the bottom surface of the second ridge; The longitudinal wall edge rises on the opposite side of the bottom surface, connected to the first curved edge, and is connected to the first longitudinal wall and the second longitudinal wall; The third ridge line is connected to the first longitudinal wall on the opposite side of the first ridge line; The fourth ridge line is connected to the second longitudinal wall on the opposite side of the second ridge line; The second curved edge line connects to the longitudinal wall edge line on the opposite side of the first curved edge line and connects the third edge line to the fourth edge line; The first flange is connected to the third ridge on the opposite side of the first longitudinal wall; The second flange is connected to the fourth ridge line on the opposite side of the second longitudinal wall; and A curved flange portion is connected to the second curved ridge on the opposite side of the longitudinal wall ridge, and connects the first flange portion to the second flange portion. When the distance from the bottom surface to the curved flange in a direction perpendicular to the bottom surface of the corner shape is defined as the corner shape height h, the radius of curvature of the longitudinal wall edge is defined as Rb, the angle between the bottom surface and the first longitudinal wall is defined as E1, and the angle between the bottom surface and the second longitudinal wall is defined as E2, the following conditions are met: 1≤h / Rb≤15 (Equation 7) 90°≤E1<105° (Equation 8) 90°≤E2 <105° (Equation 9) Formed from a single sheet of raw metal through stamping, excluding the joints between the raw metal parts, and when the thickness of the raw metal sheet is t, the radius of curvature of the first edge is r1, the radius of curvature of the second edge is r2, the radius of curvature of the third edge is r3, and the radius of curvature of the fourth edge is r4, the following conditions are met: 2.5t≤r1≤0.2h (Equation 10) 2.5t≤r²≤0.2h (Equation 11) 2.5t≤r3≤0.2h (Equation 12) 2.5t≤r4≤0.2h (Equation 13).

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