WO2024042593A1 - Procédé de fabrication et flan pour produit formé à la presse - Google Patents

Procédé de fabrication et flan pour produit formé à la presse Download PDF

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Publication number
WO2024042593A1
WO2024042593A1 PCT/JP2022/031656 JP2022031656W WO2024042593A1 WO 2024042593 A1 WO2024042593 A1 WO 2024042593A1 JP 2022031656 W JP2022031656 W JP 2022031656W WO 2024042593 A1 WO2024042593 A1 WO 2024042593A1
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WIPO (PCT)
Prior art keywords
blank
press
corner
intersection
straight line
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PCT/JP2022/031656
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English (en)
Japanese (ja)
Inventor
稔 菅原
康治 田中
貴行 野崎
昂 山本
Original Assignee
日本製鉄株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Application filed by 日本製鉄株式会社 filed Critical 日本製鉄株式会社
Priority to PCT/JP2022/031656 priority Critical patent/WO2024042593A1/fr
Priority to JP2022568532A priority patent/JP7216937B1/ja
Publication of WO2024042593A1 publication Critical patent/WO2024042593A1/fr

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
    • B21D22/20—Deep-drawing
    • B21D22/22—Deep-drawing with devices for holding the edge of the blanks
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21D24/00—Special deep-drawing arrangements in, or in connection with, presses
    • B21D24/04—Blank holders; Mounting means therefor

Definitions

  • the present invention relates to a method for producing a press-formed product and a blank.
  • Electric vehicles are being rapidly deployed with the goal of reducing CO 2 emissions, such as regulations based on CAFE (Corporate Average Fuel Efficiency).
  • CAFE Corporate Average Fuel Efficiency
  • high-priced electric vehicles are the mainstream, but in order to reduce the price of electric vehicles, it is necessary to develop parts that use metals such as steel materials.
  • molding technologies are being developed for battery boxes, front pillar lowers, door inners, etc. that use steel materials.
  • these parts are constructed to include a bottom plate, a vertical wall, and a flange, where the vertical wall has a curved corner (also referred to as a corner) and has multiple members.
  • a curved corner also referred to as a corner
  • Manufactured by welding and assembling when the radius of curvature of the corner is relatively small or when the depth of press forming is deep, wrinkles may occur in the flange near the corner.
  • the width of the flange in the circumferential direction decreases as the flange is formed. Wrinkles occur as a result of the circumferential width of the flange being reduced. This tendency becomes more pronounced as the object to be processed is a high-strength material. Further, as the height of the vertical wall of the tray increases, the amount of shrinkage of the flange increases, and therefore wrinkles are more likely to occur in the flange. The wrinkles created by the shrinkage flange remain even when the workpiece is drawn from the flange into the vertical wall of the tray. That is, wrinkles also occur on the vertical walls of the tray.
  • Patent Document 1 attempts to provide a bead on the pressing surface of the mold to control the flow direction of the material during drawing.
  • the technique of Patent Document 1 there is a high possibility that bead marks or scratches will be formed on the product after press molding, which may impair the appearance.
  • the technique of Patent Document 1 when press forming a high-strength steel material or the like, there is a high possibility that the desired effect cannot be achieved, and it is difficult to perform stable production.
  • the inventors have conducted extensive studies on the causes of suppressing the occurrence of wrinkles and cracks. Geometrically, the outer flanges at the corners of the tray shrink as they become narrower as they are drawn toward the vertical walls. In addition, in a molded product with wrinkles on the outer flange of the corner of the tray, wrinkles also occur on the edges of the molded product. From this, it is easy to think that the entire outer flange of the corner of the tray is shrinking and deforming.
  • the flow resistance from the flange toward the vertical wall is different between the straight ridgeline between the flange and the vertical wall of the tray and the corner
  • the flow resistance from the flange to the vertical wall is different between the flange and corner ridgeline adjacent to the straight ridgeline before and after forming.
  • the flanges adjacent to the corner ridgeline and their surroundings bulge away from the ridgeline. From this, the inventors thought that the end of the flange (the edge of the workpiece) was actually stretched. This hypothesis was confirmed to be correct through finite element analysis and actually forming the blank by scratching it.
  • the inventors further investigated and found that when assuming a rectangular area in the blank that perpendicularly crosses the bisector of the corner of the blank, the rectangular area becomes convex toward the corner of the blank as it is formed.
  • the inventors thought that it deforms into an arch shape.
  • the inventors thought that the concave side of the arch shape is compressively deformed and wrinkles occur.
  • the inventor believes that the convex side of the arch shape undergoes tensile deformation, but if this tensile deformation is alleviated, the deformation to the arch shape is alleviated, and as a result, the compressive deformation of the concave side of the arch shape is also alleviated, thereby suppressing the occurrence of wrinkles. thought.
  • the inventors made the distance between the edge of the corner of the die hole and the edge of the blank wider than before, compared to the distance between the edge of the die hole and the edge of the blank, which extend straight.
  • the inventors have come up with the idea that the occurrence of wrinkles can be suppressed by setting the positional relationship between the edge of the die hole and the edge of the blank in this manner.
  • the inventors came up with the idea of suppressing cracks that occur at the ridgeline of the vertical wall extending from the corner of the tray when the radius of curvature of the corner of the tray is small.
  • FIGS. 17A and 17B are explanatory diagrams for explaining the movement of points (a, b, c, d) to be processed before and after conventional press forming, based on finite element analysis results.
  • FIG. 17A is an explanatory diagram showing points to be processed before conventional press forming based on finite element analysis results.
  • FIG. 17B is an explanatory diagram showing points to be processed after press forming, based on finite element analysis results.
  • Points a and b are points located at the ends of the curved portion of the ridgeline (edge of the die hole) of the mold after molding.
  • Points c and d are points at the end of the press-formed product that are on a line that passes through the end of the curved part of the mold and is perpendicular to the extending direction of the ridgeline of the mold after molding. If you use the function of the finite element analysis software to back-calculate the blank shape from the product shape as shown in the developed diagram, the points (a, b, c, d) to be processed in Fig. 17B will be located at the positions in Fig. 17A before forming. become.
  • the inflow of the workpiece accompanying molding includes an inflow FA that is sucked into the straight ridgeline of the mold, and an inflow FB that is sucked into the curved portion of the ridgeline of the mold.
  • the inflow FA has deformation resistance that causes the workpiece to be bent by the ridgeline of the mold.
  • the inflow F B has deformation resistance in which the workpiece is compressed in a direction that crosses the inflow direction as the workpiece approaches the curved part of the mold ridgeline. . That is, the deformation resistance of the inflow F B is higher than that of the inflow F A. Therefore, the inflow amounts of inflow F A and inflow F B are not uniform.
  • the width of the flange of the molded product becomes wider at the location where the inflow F B occurs. Furthermore, the width of the flange of the molded product is widened by the workpiece pushed out from the location where the inflow F B occurs at the location where the inflow F A occurs around the location where the inflow F B occurs.
  • the flange of the molded product may be damaged by the workpiece being pulled out by the inflow F A from the location where the inflow F B occurs, even at the location where the inflow F A occurs around the location where the inflow F B occurs.
  • the width becomes wider.
  • a region H surrounded by points a, b, c, and d is deformed into an arch-like convex shape in the same direction as the convex curve of the curved portion of the ridgeline of the mold due to molding.
  • the shaded area H in FIG. 17A corresponds to the corner flange after molding. After molding, region H in FIG. 17A transforms into region H shown by diagonal lines in FIG. 17B. As shown in FIGS.
  • points a, b, c, and d move during molding.
  • point a has an inflow trajectory as shown in FIG. 17B. Wrinkles occur in the molded product because points a and b become closer together during molding.
  • the inventor thought that if the arch-like deformation of the region H surrounded by points a, b, c, and d could be alleviated, the generation of wrinkles could be suppressed. It is thought that if the stretch between points c and d can be suppressed, the arch-like deformation can be alleviated.
  • FIGS. 18A and 18B are explanatory diagrams for explaining the movement of the processing target point (a, b, c, d) before and after press forming according to the present disclosure, based on the finite element analysis results.
  • FIG. 18A is an explanatory diagram showing points to be processed before press forming according to the present disclosure, based on finite element analysis results.
  • FIG. 18B is an explanatory diagram showing points to be processed after press forming according to the present disclosure, based on finite element analysis results.
  • the dotted line in FIG. 18A shows the shape of a conventional blank.
  • Point e is the intersection of the straight line passing through points b and c and the edge of the blank.
  • point f is the intersection of the straight line passing through points a and d and the edge of the blank.
  • the blank extends outward from points c and d. It has been found that this reduces the stretching between points c and d due to molding. There are two main reasons for this. First, even if the workpiece is drawn into the curved part of the mold ridge line by the same length, the rate at which the distance between points e and f becomes closer is smaller than the rate at which the distance between points c and d approaches. small.
  • the present disclosure has been made in view of the above, and an object of the present disclosure is to provide a method for manufacturing a press-formed product and a blank that can suppress the occurrence of wrinkles in the flange portion of the press-formed product and cracks in the corner portion and the vicinity thereof. shall be.
  • a method for manufacturing a press-formed product includes sandwiching a blank between a support surface of a first press mold and a support surface of a third press mold, and placing the second press mold in the second press mold. drawing and forming the blank by pressing it into a press mold, wherein the edge line of the press hole of the first press mold has a curved area extending in a curved manner, when viewed from the vertical direction of the blank.
  • a first normal line passing through a first end of the curved area in the extending direction of the ridge line is a straight line L1
  • a second normal line passing through a second end of the curved area in the extending direction of the ridge line is a straight line L1.
  • the normal line is a straight line L2, the intersection of the straight line L1 and the edge of the blank is an intersection point M, the intersection of the straight line L2 and the edge of the blank is an intersection point N, and a line that passes through the intersection M and is perpendicular to the straight line L1
  • a straight line is a straight line L4
  • a straight line passing through the intersection N and perpendicular to the straight line L2 is a straight line L3
  • the intersection of the straight line L3 and the straight line L4 is an intersection point O
  • a line segment connecting the intersection point M and the intersection O is a line segment MO.
  • the corner end between the intersection point M and the intersection point N of the blank is the line segment MO and the line segment NO.
  • a portion of the corner end is outside a region between the line segment MO and the line segment NO.
  • the blank according to one aspect of the present disclosure is adjacent to a corner of the first rectangle, each side of which passes only through the edge and the outside of the blank, and the length of one side is 40 mm of the short side of the first rectangle. % square area, the blank touches both two sides of a second rectangle with each side passing only through the edges and inside of the blank, and the two sides of the second rectangle and the two sides of the blank In the region of the rectangle that passes through the contact point and whose corners overlap the first rectangle, the blank touches both two sides of the first rectangle.
  • the blank described in (2) above extends between the two sides of the first rectangle within 10% of the length of the short side of the first rectangle from the corner of the first rectangle. May be in contact with both.
  • the flow control area is defined on the plate surface of the corner of the blank corresponding to the corner area of the mold, so there are wrinkles in the flange part of the press-formed product and cracks in the corner part and its vicinity. The occurrence of can be suppressed.
  • the press-formed product manufacturing method and blank of the present disclosure it is possible to suppress the occurrence of wrinkles in the flange portion of the press-formed product, and cracks in the corner portions and their vicinity.
  • FIG. 2 is a schematic perspective view showing the vicinity of a corner area of a first press mold according to an embodiment of the present disclosure.
  • FIG. 2 is a diagram showing the vicinity of a corner region of a first press mold according to an embodiment of the present disclosure, and is a schematic plan view in a plan view in a direction perpendicular to the bottom surface.
  • 3 is a schematic cross-sectional view of the first press mold taken along a plane passing along the line A-A' in FIG. 2.
  • FIG. FIG. 1 is a schematic perspective view for explaining a set of press molds according to an embodiment of the present disclosure.
  • FIG. 1 is a schematic plan view for explaining a method for manufacturing a press-formed product according to an embodiment of the present disclosure.
  • FIG. 5A is a plan view showing the vicinity of a part of the corner ends shown in FIG. 5A.
  • FIG. FIG. 3 is a schematic plan view for explaining a method for manufacturing a press-formed product of a comparative example.
  • FIG. 7 is a schematic plan view for explaining a modification of the method for manufacturing a press-formed product according to an embodiment of the present disclosure.
  • FIG. 7 is a schematic plan view for explaining a modified example of the blank according to an embodiment of the present disclosure.
  • FIG. 3 is a schematic perspective view for explaining a corner area according to an embodiment of the present disclosure.
  • 1 is a diagram illustrating an example of a product in which the present disclosure can be preferably used.
  • FIG. 1 is a diagram illustrating an example of a product in which the present disclosure can be preferably used.
  • FIG. 1 is a diagram illustrating an example of a product in which the present disclosure can be preferably used.
  • FIG. 1 is a diagram illustrating an example of a product in which the present disclosure can be preferably used.
  • FIG. 1 is a diagram illustrating an example of a product in which the present disclosure can be preferably used.
  • FIG. 3 is a schematic plan view of the blank of Experimental Example 1.
  • FIG. 3 is a diagram showing the distribution of maximum principal strain obtained by finite element analysis when the blank of Experimental Example 1 was press-formed.
  • FIG. 3 is a schematic plan view of the blank of Experimental Example 2.
  • FIG. 7 is a schematic plan view of the blank of Experimental Example 3.
  • FIG. 4 is a schematic plan view of a blank of Experimental Example 4.
  • FIG. 2 is an explanatory diagram showing points to be processed before conventional press forming based on finite element analysis results.
  • FIG. 2 is an explanatory diagram showing points to be processed after conventional press forming based on finite element analysis results.
  • FIG. 2 is an explanatory diagram showing points to be processed before press forming according to the present disclosure, based on finite element analysis results.
  • FIG. 2 is an explanatory diagram showing points to be processed after press forming according to the present disclosure, based on finite element analysis results.
  • the present inventors investigated the shape of a blank to be press-formed in order to suppress wrinkles that occur in the flange part of a press-formed product, and found that by providing an extra part in the shape of a conventional blank, it was possible to suppress wrinkles during press-forming. It has been found that the flow direction of the material can be controlled, leading to the suppression of wrinkles in the flange, cracks in the corners, and their vicinity. However, on the other hand, the present inventors have also found that simply providing a surplus portion does not effectively suppress such wrinkles. As a result of extensive research, they discovered that wrinkles in the flange portion of a press-formed product can be effectively suppressed by setting an appropriate area according to the shape of the blank and the shape of the mold.
  • the method for manufacturing a press-formed product includes sandwiching a blank between a support surface of a first press mold and a support surface of a third press mold (blank clamping step), and inserting a second press mold into the second press mold. 1) Pressing the blank into a press mold and drawing the blank (blank drawing process).
  • a press mold that can carry out the blank clamping process and the blank drawing process will be described.
  • FIG. 1 shows an example of a press mold (first press mold 100) that can be employed in the method for manufacturing a press-formed product according to the present embodiment.
  • FIG. 2 is a schematic diagram showing the vicinity of the corner region 121 of the side surface 120 of the first press mold 100, and shows a plan view in a direction perpendicular to the bottom surface 110.
  • the X axis is parallel to the direction in which one plane area (plane area 122a) of the side surface 120 extends
  • the Y axis is parallel to the direction in which the other plane area (plane area 122b) of the side surface 120 extends. It is parallel to the extending direction
  • the Z axis is parallel to the perpendicular to the bottom surface 110.
  • FIG. 1 is a schematic perspective view showing the vicinity of a corner region 121 of a side surface 120 of the first press mold 100.
  • the bottom surface 110 may be a substantially planar surface.
  • the bottom surface 110 is connected to the side surface 120 at its outer edge 111.
  • the entire outer edge 111 of the bottom surface 110 may be connected to the side surface 120, or a part of the outer edge 111 may be connected to the side surface 120.
  • a portion of the outer edge 111 includes a corner 111 a corresponding to a corner region 121 of the side surface 120 .
  • the bottom surface 110 and the side surface 120 may be connected via a bottom surface side ridgeline 112 provided along the outer edge 111. In a cross-sectional view perpendicular to the extending direction of the bottom side ridgeline 112 at each point of the bottom side ridgeline 112, the bottom surface 110 and the side surface 120 are smoothly connected via the bottom side ridgeline 112.
  • a portion of the bottom side ridgeline 112 that is connected to the corner region 121 of the side surface 120 is referred to as a corner 112a.
  • the bottom surface 110 may have a concave portion or a convex portion facing out of the surface of the bottom surface 110 to provide an uneven portion on the press-formed product.
  • the side surface 120 is connected to the bottom surface 110 and stands up toward the outside of the bottom surface 110. Part or all of the side surface 120 may be parallel to the normal to the bottom surface 110 or may be inclined relative to the normal to the bottom surface 110. As shown in FIG. 1 or 2, the side surface 120 has a corner region 121 that is curved in a plan view in a direction perpendicular to the bottom surface 110. The corner area 121 is connected to the plane area 122 (plane area 122a and plane area 122b) of the side surface 120 at the end portion 121a and the end portion 121b.
  • the corner region 121 may be connected to another corner region having a different radius of curvature in a plan view perpendicular to the bottom surface 110 or to a region of the side surface 120 that is gently curved. Alternatively, the end of the corner region 121 may be the end of the side surface 120.
  • the plane area 122a and the plane area 122b are orthogonal to each other when viewed from above in a direction perpendicular to the bottom surface 110, but when viewed from above in a direction perpendicular to the bottom surface 110, the plane area 122a The angle formed by 122b is not limited to this.
  • the side surface 120 is connected to the support surface 140 via the ridgeline 130 at the end opposite to the end to which the bottom surface 110 is connected.
  • the support surface 140 is provided on the side opposite to the bottom surface 110 with respect to the side surface 120.
  • a portion of the ridgeline 130 that is connected to the corner region 121 of the side surface 120 is referred to as a curved region 131.
  • the curved region 131 of the ridgeline 130 is connected to the straight region 132 (straight region 132a and straight region 132b) of the ridgeline 130 at the terminal end 131a and the terminal end 131b.
  • the curved region 131 may be connected to another curved region having a different radius of curvature in a plan view perpendicular to the bottom surface 110 or to a region of the ridge line 130 that curves gently.
  • the terminal end of the curved region 131 may be the end of the ridgeline 130.
  • the terminal ends (terminal end 131a and terminal end 131b) of the curved region 131 each include a terminal point (first end) P1 and a terminal point (second end) P2, which will be described later.
  • FIG. 3 shows a schematic cross-sectional view of the first press mold 100 taken along a plane passing along the line A-A' in FIG. 2.
  • the bottom surface 110 and the corner region 121 of the side surface 120 are smoothly connected via the corner 112a of the bottom surface side ridgeline 112, and the corner region 121 of the side surface 120 and the support surface 140 are connected to each other through the curve of the ridgeline 130. They are smoothly connected via region 131.
  • the corner region 121 of the side surface 120 is inclined with respect to the normal to the bottom surface 110.
  • the corner region 121 may be perpendicular to the bottom surface 110 in each cross section orthogonal to the bottom surface 110.
  • the first press mold 100 has a press hole 123.
  • the second press mold 200 is pushed into the press hole 123 by relatively moving the first press mold 100 and the second press mold 200, which will be described later, in a direction in which they approach each other.
  • the ridgeline 130 of the edge of the press hole 123 (the edge on the second press mold 200 side) includes a curved region 131 that extends in a curved manner.
  • the first press mold 100 may include one or more corner regions 121.
  • the bottom surface 110 of the first press mold 100 corresponds to the bottom plate part of the press molded product
  • the side surface 120 corresponds to the vertical wall part of the press molded product
  • the support surface 140 corresponds to the flange part of the press molded product.
  • Press molding is performed by a set of press molds 1000 including the first press mold 100, the second press mold 200, and the third press mold 300 described above.
  • FIG. 4 shows an example of a set of press molds 1000 including a first press mold 100, a second press mold 200, and a third press mold 300.
  • FIG. 4 illustrates a press mold 1000 including a first press mold 100 having four corner regions 121, the shape of the press mold is not limited to this, and the number of corner regions 121 and the shape of the bottom surface 110 are not limited to this shape. is not particularly limited.
  • the second press mold 200 has a bottom surface 210 corresponding to the bottom surface 110 of the first press mold 100, a side surface 220 corresponding to the side surface 120 of the first press mold 100, and a corner area 121 of the first press mold 100.
  • a corner area 221 corresponding to the corner area 221 is provided.
  • the outer surface shapes of the bottom surface 210 and side surfaces 220 of the second press mold 200 correspond to the outer surface shapes of the bottom surface 110 and side surfaces 120 of the first press mold 100.
  • the first press die 100 and the second press die 200 By relatively moving the first press die 100 and the second press die 200 in the direction (pressing direction), the blank is plastically deformed between the first press die 100 and the second press die 200. let The first press mold 100 is also called a die.
  • the second press die 200 is also referred to as a punch.
  • the third press mold 300 includes a support surface 340 corresponding to the support surface 140 of the first press mold 100.
  • the support surface 140 of the first press mold 100 and the support surface 340 of the third press mold 300 are arranged to face each other. , can hold the blank, which is the workpiece.
  • the blank is held between the support surface 140 of the first press mold 100 and the support surface 340 of the third press mold 300 so that it can move in the in-plane direction without moving in the out-of-plane direction.
  • the third press mold 300 is also referred to as a holder.
  • the first press mold 100, the second press mold 200, and the third press mold 300 may each be constructed from a single member, or each may be constructed from a divided mold. Further, the press mold 1000 may include molds other than these molds.
  • FIG. 5A is a schematic plan view for explaining the method for manufacturing a press-formed product according to the present embodiment of the present disclosure.
  • FIG. 5A is a plan view of the plate-shaped blank 10 in a direction perpendicular to the plate surface.
  • FIG. 5B shows the vicinity of a part of the corner ends 11 of the blank 10 shown in FIG. 5A.
  • FIG. 5B shows the ridgeline 130 of the die hole (press hole 123) and the ridge line 130 of the blank 10 when the blank 10 is placed on the die (first press mold 100) and sandwiched between the blank holders (third press mold 300). Indicates the position of the edge.
  • the first normal line passing through the first end P1 in the extending direction of the ridgeline 130 of the curved region 131 is the straight line L1
  • the second normal line in the extending direction of the ridgeline 130 of the curved region 131 is The second normal passing through the end P2 of is the straight line L2
  • the intersection of L1 and the end of the blank 10 is the intersection M
  • the intersection of the straight line L2 and the end of the blank 10 is the intersection N
  • the straight line perpendicular to L1 is the straight line L4
  • the straight line perpendicular to the straight line L2 is the straight line L3
  • the straight line L4 is the intersection point O
  • the line segment connecting the intersection point M and the intersection point O is the line segment MO
  • the intersection point A line segment connecting N and intersection O is defined as line segment NO.
  • the end of the blank 10 between the intersection M and the intersection N is defined as a corner end 11.
  • the corner end portion 11 is a portion outside the blank 10 from the line segment MN connecting the intersection point M and the intersection point N.
  • the corner end 11 includes all the line segments MO and NO, and one part of the corner end 11 includes the line segment MO and the line segment NO. is outside the area between line segment MO and line segment NO.
  • line segment MO and line segment NO have the shapes of the ends of a conventional blank.
  • the edge of the corner end 11 of the blank 10 is located outside the region sandwiched between the line segment MO and the line segment NO, and the edge of the corner end 11 of the blank 10 is located inside the region sandwiched between the line segment MO and the line segment NO. There isn't.
  • the corner end 11 of the blank 10 is outside the area between the line segment MO and the line segment NO. That is, the blank 10 has a shape in which the corner end portions 11 protrude outward.
  • the corner end portion 11 has a convex shape toward the outside of the corner of the blank 10.
  • the corner end portion 11 can also be said to have an arch shape toward the outside of the corner of the blank 10.
  • corner ends 11 do not need to be set at all corners in the blank 10, and the corner ends 11 may be set only at some of the corners.
  • the method for manufacturing a press-formed product it is possible to define an appropriate corner end 11 for the blank, so wrinkles in the flange portion of the press-formed product and cracks in the corner portion and the vicinity thereof can be prevented. It can be suppressed. In the corner portions, cracking can be particularly suppressed at the corner portions 112a.
  • the corner portion 112a is a portion that continues to be stretched from the start to the end of press molding, and is the portion where cracks are most likely to occur.
  • FIG. 6 is a schematic plan view for explaining a modification of the method for manufacturing a press-formed product according to an embodiment of the present disclosure.
  • FIG. 6 shows the position of the edge line 130 of the die hole and the edge of the blank 10 when the blank 10 is placed on the die (first press die 100) and sandwiched between the blank holders (third press die 300). ing.
  • FIG. 6 shows the vicinity of one corner end 11 of the corner ends of the blank 10.
  • a part of the corner end 11 of the blank 10 is located outside the region between the line segment MO and the line segment NO, similar to FIG. 5B. That is, the blank 10 has a shape in which the corners protrude outward.
  • the corner end portion 11 has a convex shape toward the outside of the corner of the blank 10. Further, the corner end portion 11 can also be said to have an arch shape toward the outside of the corner of the blank 10.
  • FIGS. 5A and 5B show the vicinity of some of the corner ends 11 of the blank 10, but the corner ends 11 are approximately straight lines in a plan view in a direction perpendicular to the plate surface of the blank 10. This is the point where the first side S1 and the second side S2 of the shaped blank 10 intersect.
  • the field of view in FIGS. 5A and 5B is a square of 40% of the short side of a rectangular cutting board, adjacent to a corner of a first rectangle R1, each side of which passes only the edge and outside of the blank 10. An area A1 is assumed.
  • the blank 10 is molded so deeply that the corner of the ridgeline 1300 of the mold does not fit within this area A1 as shown in FIG. 5C, there is a concern that cracks may occur even using the knowledge of the present disclosure. If the corner of the ridge line 1300 of the mold does not fall within this region A1 and molding is performed to the extent that cracks do not occur, the width of the flange becomes excessive. In other words, the yield is poor.
  • the blank 10 is in contact with both two sides of the second rectangle R2, each side of which passes only through the edges and inside of the blank 10, and the two sides of the second rectangle R2 and the two contact points of the blank 10.
  • the blank 10 touches both of the two sides of the first rectangle R1.
  • blank 10 touches two points X1 and X2 on both sides of first rectangle R1.
  • the edge of the blank 10 and the edge of the rectangular cutting plate may coincide with each other from the two points X1 and X2 to the corner of the rectangular cutting plate.
  • Each side of the first rectangle R1 passes only through the edge and outside of the blank.
  • the first rectangle R1 has the shape of a rectangular cut plate.
  • Each side of the second rectangle R2 passes only through the edge and inside of the blank.
  • the second rectangle passes through intersections N and M with intersection O as its corner.
  • the blank 10 is placed on both two sides of the second rectangle R2. come into contact with In the region illustrated in FIG. 5B, the edge of the blank 10 passes through the intersections M and N.
  • the blank 10 contacts both of the two sides of the first rectangle R1.
  • the edge of the blank 10 touches the edge of the cutting plate in a region surrounded by the edge of the cutting plate, the straight line L1, and the straight line L2.
  • Press forming is performed by arranging the positions of the intersection point M and the intersection point N of the blank 10 having such a shape and the ridge line 130 of the die hole (press hole 123) as explained in the above-mentioned method for manufacturing a press-formed product. Then, the method for manufacturing a press-formed product of the present disclosure can be carried out.
  • FIG. 7 is a schematic plan view for explaining a modification of the blank according to an embodiment of the present disclosure.
  • a rectangular (rectangular) blank 10 is shown, but the shape of the blank 10 is not limited to this. may be provided. A part of the corner end 11 may become a part of the flange of the press-formed product after press-forming. The shape of the press-formed product may be adjusted by trimming the flange. In this case, the blank 10 has a shape that includes corner ends 11 at the corners of the blank 10 .
  • the blank 10 may be a steel plate, an aluminum alloy plate, a titanium alloy plate, or a composite material thereof. As the blank 10, it is more preferable to use a steel plate having a tensile strength of 270 to 440 MPa from the viewpoint of material elongation. Further, the blank 10 may be a high-strength steel plate, for example, a steel plate having a tensile strength of 980 MPa or more. Even when the tensile strength of the blank 10 according to this embodiment is high, the effect of suppressing wrinkles and cracks can be obtained. Furthermore, the blank 10 may be subjected to processing such as plating for the purpose of rust prevention and corrosion prevention.
  • a corner end 11 is defined on the plate surface of the corner of the blank 10. Therefore, it is possible to suppress the occurrence of wrinkles in the flange portion of a press-formed product press-formed from this blank 10 and cracks in the corner portion and the vicinity thereof.
  • the corner region where the corner end portion 11 is set is convex from the bottom side to the supporting surface side with respect to the side surface in a plan view in a direction perpendicular to the bottom surface of the first press mold.
  • the corner area is That is, in a plan view in a direction perpendicular to the bottom surface of the first press mold, a corner region that is convex from the support surface side to the bottom surface side with respect to the side surface is not a target of the above embodiment.
  • the side area B of the first press die shown in FIG. 8 is convex from the supporting surface side to the bottom side with respect to the side surface, and is not subject to the method for setting the corner end 11 according to the present disclosure. .
  • the above-mentioned corner end portion is set with these plurality of corner regions as one corner region.
  • the side region C of the first press mold shown in FIG. 8 includes a plurality of corner regions 121' and 121'' having different radii of curvature.
  • the side surface area C of the first press die shown in FIG. 8 is convex from the bottom side to the supporting surface side with respect to the side surface, and can be set as a setting target of the setting method of the corner end 11 according to the present disclosure.
  • the thickness of the blank is appropriately set depending on the characteristics required of a press-formed product obtained by press-molding the blank.
  • the thickness of the blank may be the average thickness of the metal plate that is the workpiece.
  • the average plate thickness may be the average value of the plate thicknesses at a plurality of arbitrary points on the metal plate (for example, three points in the range formed into the vertical wall portion or the bottom plate portion).
  • the thickness of the metal plate may be substantially the same as the thickness of the vertical wall preformed part or the bottom plate preformed part of the preformed product, or the thickness of the vertical wall part or the bottom plate part of the press formed product.
  • the thickness of the metal plate may be substantially the same as the clearance between the first mold and the second mold, or the clearance between the fourth mold and the fifth mold.
  • the radius of curvature of the corners is small, problems with cracks and wrinkles become apparent. Even in such a case, by implementing the press molding method of the present disclosure, the occurrence of cracks and wrinkles can be suppressed.
  • the smallest radius of curvature of the curvature in the extending direction of the ridge line 130 of the die hole (press hole 123) where the problem of cracking becomes apparent is 20 mm or less. This radius of curvature corresponds to 30 times the thickness of the blank.
  • the angle between the tangent to the ridgeline at the termination point P1 and the tangent to the ridgeline at the termination point P2 is not particularly limited.
  • it can be an acute angle as shown in FIG.
  • the angle between the tangent to the ridgeline at the termination point P1 and the tangent to the ridgeline at the termination point P2 is 30° or more and 150° or less. .
  • the planar region of the side surface of the first press die has a radius of curvature of 500 mm or more when viewed from above in a direction perpendicular to the bottom surface. Further, in the embodiment described above, it is more preferable that the height of the side surface of the first press mold is 20 times or more and 200 times or less the thickness of the blank 10.
  • the width of the flange portion of the blank 10 may be asymmetrical. That is, the length of the line segment OM and the length of the line segment ON may be different. Even in such a case, since an appropriate flow control region can be defined for the blank 10, it is possible to suppress the occurrence of wrinkles in the flange portion of the press-formed product and cracks in the corner portion and the vicinity thereof.
  • the press-formed product may be a final product, or an intermediate product to be further processed (press-forming, cutting, bending, welding, heating/cooling, plating, painting) into a final product. There may be.
  • the press-formed product according to the above embodiment has a corner portion corresponding to the corner area of the first press mold, and is suitable for use in vehicles such as battery boxes, front pillar lowers, door inners, etc. represented by battery boxes for vehicles. It can be preferably used for parts.
  • 9A to 12 are diagrams for explaining an example of a product in which the press-formed product manufacturing method and blank according to the present disclosure can be preferably used.
  • the press-molded product illustrated in FIG. 9A is a corner part 301 of a battery box, and has two corner parts 331 and 331'.
  • the press-molded product illustrated in FIG. 9B is a corner part 302 of a battery box, and has a corner part 332.
  • the entire battery box may be formed by joining these press-molded products with other members.
  • the press-molded product illustrated in FIG. 10 is a front pillar 303 having a corner portion 333.
  • the present disclosure can also be preferably applied to such a member whose entire body is curved into an L-shape.
  • the press-molded product illustrated in FIG. 11 is a C-pillar stiffener 304, and the vertical wall is high near the corner portion 334. In this way, the present disclosure can be preferably applied to members whose vertical walls are not uniform in height.
  • the press-molded product illustrated in FIG. 12 is a door inner 305.
  • the present disclosure can also be preferably applied to a press-molded product having a plurality of corner portions 335 and 335' having different curvature radii and opening angles, such as the door inner 305.
  • press forming was performed on each blank having corner portions shaped as shown in FIGS. 13A, 14, 15, and 16, and the strain distribution at the flange portion of the press-formed product was verified by finite element analysis. .
  • the figures shown in FIGS. 13A, 14, 15, and 16 show the vicinity of some corners of each blank. Common to all blanks, the tensile strength of the blank was 270 MPa, and the plate thickness was 0.8 mm.
  • the principal strain is three vertical strain components when the coordinate system Cp in which the shear strain is zero is used as a reference.
  • the principal strains are defined as "maximum principal strain ( ⁇ 1),” “intermediate principal strain ( ⁇ 2),” and “minimum principal strain ( ⁇ 3)” in order from the largest value.
  • Maximum principal strain is generally used to evaluate the maximum tensile strain that can be applied to a material. If this maximum principal strain is large, it can be determined that the material is likely to break. Note that the maximum principal strain can be determined using general finite element analysis software.
  • One of the functions of software commonly used in forming analysis is the function of back calculating the blank shape from the product shape as in a developed diagram (developed blank analysis).
  • a common blank design for those skilled in the art is to analyze using this function and consider the shape of the developed blank as a reference.
  • FIG. 13A is a schematic plan view of the blank 500 of Experimental Example 1. Corner end 511 of blank 500 is inside the area between line segment MO and line segment NO. That is, blank 500 is a conventional example.
  • FIG. 13B the blank 500 is shown by a two-dot chain line, and the shape after molding is shown by a solid line. The location showing the maximum value of the maximum principal strain in Experimental Example 1 was the location surrounded by the dotted line circle in FIG. 13B (near the curved region), and the maximum value was 0.85.
  • FIG. 14 is a schematic plan view of the blank 600 of Experimental Example 2. Corner end 611 of blank 600 is inside the area between line segment MO and line segment NO. That is, blank 600 is a conventional example.
  • FIG. 15 is a schematic plan view of the blank 700 of Experimental Example 3. A part of the corner end 711 of the blank 700 is outside the area between the line segment MO and the line segment NO, but the corner end 711 does not entirely include the line segment MO and the line segment NO.
  • the location showing the maximum value of the maximum principal strain in Experimental Example 3 corresponds to the location surrounded by the dotted line circle in FIG. 13B, and the maximum value was 0.92.
  • FIG. 16 is a schematic plan view of the blank 10 of Experimental Example 4. All of the corner edges 11 of the blank 10 are outside the area between the line segments MO and NO. That is, blank 10 is an example of the invention.
  • the location showing the maximum value of the maximum principal strain in Experimental Example 4 corresponds to the location surrounded by the dotted line in FIG. 13B, and the maximum value was 0.73.
  • Blank 10 showed an improvement in maximum principal strain compared to the conventional example.
  • the corner end 11 should include all of the line segments MO and NO, and a part of the corner end 11 should be an area between the line segments MO and NO. It turns out that it is necessary to be outside of the corner end 11

Abstract

Ce procédé de fabrication pour un produit formé à la presse comprend : la mise en sandwich d'un flan (10) entre une surface de support (140) d'une première matrice de presse (100) et une surface de support (340) d'une troisième matrice de presse (300) ; et l'insertion par poussée d'une deuxième matrice de presse (200) dans la première matrice de presse (100) pour former le flan (10). Une ligne de crête (130) au niveau d'un bord d'un trou de presse (123) de la première matrice de presse (100) est pourvue d'une région incurvée (131) qui s'étend de manière incurvée. Lorsqu'une extrémité de coin prescrite (11) est définie, l'extrémité de coin (11) entre une intersection M et une intersection N du flan (10) comprend la totalité d'un segment de ligne MO et la totalité d'un segment de ligne NO, et une partie de l'extrémité de coin (11) est à l'extérieur d'une zone entre le segment de ligne MO et le segment de ligne NO.
PCT/JP2022/031656 2022-08-23 2022-08-23 Procédé de fabrication et flan pour produit formé à la presse WO2024042593A1 (fr)

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JP2022568532A JP7216937B1 (ja) 2022-08-23 2022-08-23 プレス成形品の製造方法及びブランク

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63112029A (ja) * 1986-10-30 1988-05-17 Nippon Denso Co Ltd 円筒絞り加工方法
JPH0428424A (ja) * 1990-05-21 1992-01-31 Nissan Motor Co Ltd プレス型
JP2002170529A (ja) * 2000-12-01 2002-06-14 Hara Press Engineering:Kk バッテリケース、バッテリケース用ブランク、及びバッテリケースの製造方法
JP2017192972A (ja) * 2016-04-21 2017-10-26 三菱アルミニウム株式会社 アルミニウム樹脂複合積層板の絞り成形用ブランク材及びこれを用いた三次元成形品の製造方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63112029A (ja) * 1986-10-30 1988-05-17 Nippon Denso Co Ltd 円筒絞り加工方法
JPH0428424A (ja) * 1990-05-21 1992-01-31 Nissan Motor Co Ltd プレス型
JP2002170529A (ja) * 2000-12-01 2002-06-14 Hara Press Engineering:Kk バッテリケース、バッテリケース用ブランク、及びバッテリケースの製造方法
JP2017192972A (ja) * 2016-04-21 2017-10-26 三菱アルミニウム株式会社 アルミニウム樹脂複合積層板の絞り成形用ブランク材及びこれを用いた三次元成形品の製造方法

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