JP6586895B2 - Press device and method for manufacturing press-formed product - Google Patents

Description

  The present invention relates to a pressing apparatus and a manufacturing method for pressing a metal plate. More specifically, the present invention relates to a press apparatus and a manufacturing method for manufacturing a press-formed product having at least a contracted flange forming portion.

  Automotive frame parts and the like are required to have high strength in order to ensure the safety of the vehicle body. Such a part may be formed into a groove shape in cross section by pressing a metal plate. On the other hand, in recent years, the weight reduction of the vehicle body has been promoted in order to improve the fuel consumption of automobiles. For this reason, thinning is required for automobile parts.

  In order to reduce the thickness while maintaining the strength of the frame parts and the like, it is necessary to increase the strength of the workpiece to be the material of the frame parts and the like. However, when a part is manufactured by press working, if the strength of the workpiece is increased, the amount of spring back after the mold is released increases, making it difficult to ensure dimensional accuracy. Springback is caused by excessive residual stress.

  In particular, when manufacturing a part having a groove-shaped cross section (specifically, a U-shaped cross section) as represented by an automobile frame part using a high-strength work material, The springback amount increases at the end of the press-formed product having a groove-shaped cross section, and a part having a desired dimensional accuracy may not be obtained.

  Japanese Patent Laying-Open No. 2015-27698 (Patent Document 1) discloses a press device that suppresses springback. The press apparatus described in Patent Document 1 manufactures a press-molded product including a vertical wall portion, a top plate portion, and a flange portion connected to the vertical wall portion. This press-molded product is curved along the longitudinal direction. Patent Document 1 describes that the spring back amount of the vertical wall portion is reduced by changing the longitudinal length of the curved inner flange portion and the curved outer flange portion of the press-molded product during press molding. Has been.

JP2015-27698A

  However, the part manufactured by the press apparatus described in Patent Literature 1 is a hat-shaped cross-section press-molded product including a flange portion connected to a vertical wall portion. In the press-formed product having a hat-shaped cross section, the amount of spring back at the end of the vertical wall is small. On the other hand, the vertical wall portion of the press-formed product having a groove-shaped cross section has no flange portion, and the spring back amount at the end portion of the vertical wall portion is large. Since the press apparatus described in Patent Document 1 is a press-molded product having a hat-shaped cross section, it is not certain whether the amount of spring back at the end of the vertical wall portion without the flange portion can be reduced.

  The present invention has been made in view of the above circumstances. The objective of this invention is providing the press apparatus and manufacturing method which can reduce the springback amount of the edge part of the press-formed product of a channel-shaped cross section.

  The press apparatus by embodiment of this invention is provided with a punch, a blank holder, and die | dye. The blank holder is disposed adjacent to the punch. The die includes a die shoulder and a plate pressing surface. A region of a part of the die shoulder is curved in a concave shape along the extending direction of the die shoulder (the die shoulder boundary is curved toward the die). The horizontal distance between the edge of the die shoulder and the edge of the blank holder in the region other than the region curved into the concave shape of the die shoulder is the distance between the die shoulder boundary and the blank in the region curved into the concave shape of the die shoulder. It is wider than the horizontal distance between the edge of the holder. The die shoulder boundary line is defined by an R stop on the plate pressing surface side of the die shoulder.

  The manufacturing method of the press-formed product according to the embodiment of the present invention includes a preparation step and a pressing step. In the preparation step, a workpiece made of a metal plate is prepared. In the pressing process, the workpiece is formed into a press-formed product by pressing. The press-formed product has a channel-shaped cross section. The press-molded product includes a top plate portion and a vertical wall portion connected to the top plate portion. The press-molded product has a partially contracted flange portion. In the pressing process, a punch, a blank holder, and a die are used. The blank holder is disposed adjacent to the punch. The die includes a die shoulder and a plate pressing surface. A shape reflecting the shape of the contracted flange portion of the press-formed product is formed in a partial region of the die shoulder. The distance in the horizontal direction between the die shoulder boundary and the edge of the blank holder in the region other than the region where the shape reflecting the shape of the shrinking flange portion of the die shoulder is the shape of the shrinking flange portion of the die shoulder. It is wider than the distance in the horizontal direction between the die shoulder boundary line and the edge of the blank holder in the region where the reflecting shape is formed. The die shoulder boundary line is defined by an R stop on the plate pressing surface side of the die shoulder.

  The press apparatus and the press-molded product manufacturing method of the present invention can suppress the spring back at the end of the groove-shaped press-molded product.

FIG. 1A is a perspective view of a workpiece. 1B is a perspective view of a frame component molded from the workpiece shown in FIG. 1A. FIG. 2A is a diagram illustrating an initial state of molding by a conventional press apparatus. FIG. 2B is a diagram showing a state in the middle of molding by a conventional press device. FIG. 2C is a diagram illustrating a state at the end of molding by a conventional press device. FIG. 2D is a diagram illustrating a frame component formed by a conventional press device. FIG. 3 is a perspective view showing the press device of the first embodiment. FIG. 4 is a diagram showing a state in the middle stage of molding by the press device of the first embodiment, and shows a IV-IV cross section in FIG. 3. FIG. 5 is an enlarged cross-sectional view of the vicinity of the die shoulder in FIG. FIG. 6 is a view showing an initial state of molding by the press apparatus of the first embodiment, and shows a VI-VI cross section in FIG. 3. FIG. 7 is a view showing a state in the middle stage of molding by the press device of the first embodiment, and shows a VI-VI cross section in FIG. 3. FIG. 8 is a perspective view of a frame component manufactured by the press device according to the second embodiment. FIG. 9 is a diagram showing a state in the middle stage of molding by the press device of the second embodiment, and shows a cross section IX-IX in FIG. 8.

  The press device according to the present embodiment includes a punch, a blank holder, and a die. The blank holder is disposed adjacent to the punch. The die includes a die shoulder and a plate pressing surface. A region of a part of the die shoulder is curved in a concave shape along the extending direction of the die shoulder (the die shoulder boundary is curved toward the die). The distance in the horizontal direction between the die shoulder boundary and the edge of the blank holder in the region other than the region curved in the concave shape of the die shoulder is the distance between the die shoulder boundary in the region curved in the die shoulder and the blank holder. It is wider than the horizontal distance between the edges. The die shoulder boundary line is defined by an R stop on the plate pressing surface side of the die shoulder.

  For example, a press-molded product such as an automobile frame part does not have a flange portion connected to a vertical wall portion, but has a contracted flange-formed portion in part. As a result of studies by the present inventors, it has been found that the spring back of the end portion is unlikely to occur in the contracted flange molded portion. On the other hand, it was found that the spring back of the end portion is likely to occur in the region other than the shrink flange forming portion (for example, the straight forming portion). In view of this, the present inventor has paid attention to a region of a mold for forming a shrinkage flange forming portion and a region of a mold for forming a portion other than the shrinkage flange forming portion.

  In the press apparatus according to the present embodiment, an area in which a workpiece is sandwiched by a blank holder is secured in an area of a mold for forming a shrinkage flange forming portion. This is because it is necessary to suppress the generation of wrinkles.

  On the other hand, in the region of the mold for molding other than the shrinkage flange forming portion, the region where the workpiece is sandwiched by the blank holder is reduced. In other words, the material to be processed comes out from between the blank holder and the die at an early stage during the press work except for the contracted flange forming portion. Thereby, the amount of bending and the amount of bending back of the end portion of the workpiece are reduced. As a result, the residual stress at the end of the vertical wall portion is reduced, and the amount of spring back at the end of the formed vertical wall portion can be reduced.

  In the press apparatus described above, the die shoulder boundary line preferably coincides with the edge of the blank holder in the horizontal direction in the concave region of the die shoulder.

  In the above pressing apparatus, the following configuration can be employed. The press device may include a pad arranged to face the punch. In this case, the workpiece to be pressed is sandwiched between the punch and the pad. This makes it easier for the workpiece to follow the shape of the punch and improves the dimensional accuracy of the press-formed product.

  The press device preferably employs the following configuration. In a region other than the region curved in the concave shape of the die shoulder, the distance in the horizontal direction between the die shoulder boundary line and the edge of the blank holder is 10 mm or more. In this case, even in a high-strength workpiece, the amount of springback at the end is effectively reduced.

  The press apparatus described above can employ the following configuration. The die shoulder may further have a convex curved region. In this case, the press-molded product has an elongated flange formed part. Further, the blank holder may be disposed adjacent to both sides of the punch.

  The manufacturing method of the press-formed product of the present embodiment using the above-described pressing apparatus includes a preparation process and a pressing process. In the preparation step, a workpiece made of a metal plate is prepared. In the pressing process, the workpiece is formed into a press-formed product by pressing. The press-formed product has a channel-shaped cross section. The press-molded product includes a top plate portion and a vertical wall portion connected to the top plate portion. The press-molded product has a partially contracted flange portion. In the pressing process, a punch, a blank holder, and a die are used. The blank holder is disposed adjacent to the punch. The die includes a die shoulder and a plate pressing surface. A shape reflecting the shape of the contracted flange portion of the press-formed product is formed in a partial region of the die shoulder. The distance in the horizontal direction between the die shoulder boundary and the edge of the blank holder in the region other than the region where the shape reflecting the shape of the shrinking flange portion of the die shoulder is the shape of the shrinking flange portion of the die shoulder. It is wider than the distance in the horizontal direction between the die shoulder boundary line and the edge of the blank holder in the region where the reflecting shape is formed. The die shoulder boundary line is defined by an R stop on the plate pressing surface side of the die shoulder.

  In said manufacturing method, it is preferable that the tensile strength of a workpiece is 440 Mpa or more. The plate thickness of the workpiece is preferably 2.3 mm or more.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated. Below, the case where the frame component of the motor vehicle which has a groove-shaped cross section as a press-formed product is manufactured is illustrated.

  FIG. 1A to FIG. 1B are diagrams showing steps of manufacturing a frame part in stages. FIG. 1A is a perspective view of a workpiece used for manufacturing a frame component. 1B is a perspective view of a frame component molded from the workpiece shown in FIG. 1A.

  As shown in FIG. 1A, the workpiece S has a shape according to the frame part shape. As long as the yield can be lowered, the workpiece S may not have a shape strictly conforming to the shape of the final product. This is because trim processing or the like is performed in a later process. The workpiece S is made of a metal plate. The metal plate is, for example, a steel plate or an aluminum plate.

  A workpiece S shown in FIG. 1A is formed into a frame component 1 having a groove-shaped cross section by pressing. As shown in FIG. 1B, the frame component 1 includes a vertical wall portion 2 and a top plate portion 3. However, the frame component 1 does not have a flange portion connected to the vertical wall portion 2. The vertical wall part 2 includes a flange-formed part 4 which is contracted in a part of the extending direction (longitudinal direction). Further, the vertical wall portion 2 includes an elongated flange forming portion 5 and a linear forming portion 6 in a part in the extending direction. Here, the contracted flange forming portion 4 refers to a region of the curved region of the frame component 1 where a compressive force acts in the extending direction during press working. The stretch flange forming part 5 refers to a region of the curved region of the frame part 1 where tension acts in the extending direction during press working. The straight line forming portion 6 is a region other than the shrinkage flange forming portion and the stretch flange forming portion, and refers to a region where a force does not substantially act in the extending direction during press working.

  As described above, if the springback amount of the end 7 of the vertical wall portion 2 in the frame component 1 shown in FIG. 1B is large, for example, when a structure is formed by joining with other components by arc welding or the like, welding is performed. It causes sexual deterioration. In order to eliminate this inconvenience, in the frame component 1 shown in FIG. 1B, it is necessary to reduce the residual stress at the end 7 of the vertical wall 2 and to reduce the amount of spring back.

[Mechanism that the end of the vertical wall of the press-molded product springs back]
2A to 2C are cross-sectional views showing a state in which a workpiece is formed into the frame component shown in FIG. 1B by a conventional press device. Among these drawings, FIG. 2A is a diagram showing an initial state of press molding. FIG. 2B is a diagram illustrating an intermediate state of press molding. FIG. 2C is a diagram illustrating a state at the end of press molding. FIG. 2D is a diagram showing a frame part that has been press-molded.

  As shown in FIG. 2A, a conventional press apparatus 100 includes a punch 101 and a blank holder 102 as an upper mold and a die 103 as a lower mold. The workpiece S is disposed at a predetermined position of the press device 100. Thereafter, the slide of the press device 100 is lowered, and first, the workpiece S is sandwiched between the blank holder 102 and the die 103. In this state, the punch 101 is pushed into the die 103 as the slide is further lowered. At that time, the workpiece S is bent along the die shoulder 104. That is, in FIG. 2A, the workpiece S is bent excessively at an angle θ1 of approximately 90 ° (see FIG. 2B). Accordingly, in the bent region X of the workpiece S, a tension acts on the front side (punch 101 side), and a compressive force acts on the back side (die 103 side).

  As shown in FIG. 2B, when the punch 101 is further pushed, the bent region X shown in FIG. 2A moves between the side surface 105 of the punch 101 and the inner side surface 106 of the die 103. At that time, the bent region X is straightened (hereinafter also referred to as “bending back”) by the side surface 105 of the punch 101 and the inner side surface 106 of the die 103. That is, bending back at an angle θ1 is performed. Due to this excessive bending back, a compressive force is applied to the front side of the region X where the tension is applied, and a tension is applied to the back side of the region X where the compressive force is applied. This stressed state continues until just before the bottom dead center of the molding by the punch 101.

  As shown in FIG. 2C, when the punch 101 reaches the bottom dead center of molding, the entire area of the vertical wall portion 2 of the frame part is molded, and the frame part 1 is obtained.

  As shown in FIG. 2D, when the frame part 1 is taken out from the press device, the vertical wall portion 2 of the frame part 1 is released from the restraint caused by the side surface 105 of the punch 101 and the inner side surface 106 of the die 103. By this, it tries to return to the shape before molding (in the direction of the arrow in FIG. 2D) (hereinafter also referred to as “spring back”). In particular, when the workpiece S has high strength or the workpiece S has a large plate thickness, the end 7 of the vertical wall portion 2 is likely to spring back.

  As shown in FIGS. 2A to 2C, according to the conventional press device 100, the end 7 of the vertical wall portion 2 comes out from between the blank holder 102 and the die 103 immediately before the molding bottom dead center. Therefore, excessive bending and unbending by the punch 101 and the die 103 are performed up to the tip of the end portion 7 of the vertical wall portion 2. Therefore, residual stress due to excessive bending and unbending occurs at the tip of the end 7 of the vertical wall 2. Therefore, the end portion 7 of the vertical wall portion 2 of the frame part 1 is likely to spring back.

  Moreover, as a result of investigating the amount of springback for each region of the frame part 1 shown in FIG. 1B, the present inventor obtained the following knowledge. In the contracted flange molded part 4 and the stretched flange molded part 5 of the frame part 1, the amount of spring back at the end 7 of the vertical wall part 2 is small. On the other hand, in the linear molding part 6, the springback amount of the end part 7 of the vertical wall part 2 is large.

  The present invention has been completed based on the above theory and knowledge. Below, the press apparatus of this embodiment is explained in full detail.

[First Embodiment]
[Pressing equipment]
FIG. 3 is a perspective view showing the press device of the first embodiment. The press apparatus 10 according to the first embodiment includes a die 21 as a lower die and a punch 31 and a blank holder 41 as an upper die. FIG. 3 shows a case where the press device 10 includes a pad 25. However, the press device 10 may not include the pad 25. This is because the pad 25 is unnecessary when high dimensional accuracy is not required for the top plate portion 3 of the frame component 1 or when dimensional accuracy of the top plate portion 3 is ensured without the pad 25.

  The die 21 and the pad 25 are supported by a lower mold holder (not shown). The lower mold holder is attached to a bolster plate (not shown). On the other hand, the punch 31 and the blank holder 41 are supported by an upper mold holder (not shown). The upper mold holder is attached to a slide (not shown). The pad 25 and the blank holder 41 are supported by a pressure member (not shown). The pressurizing member is a hydraulic cylinder, a gas cylinder, a spring, rubber, or the like. In addition, arrangement | positioning of the die | dye 21, the punch 31, and the blank holder 41 is not limited to the case shown in FIG. The arrangement of these molds may be reversed upside down. In short, the punch 31 and the blank holder 41 may be configured to move relative to the die 21.

  The die 21 and the pad 25 face the punch 31 and the blank holder 41. In particular, the pad 25 faces the punch 31. The die 21 has the shape of the frame component 1 shown in FIG. 1B. The shape of the top plate portion 3 of the frame component 1 shown in FIG. 1B is formed on the pad 25. The die 21 has a plate pressing surface 22, an inner wall 23, and a die shoulder 24. The plate pressing surface 22 faces the blank holder 41. A space is provided between the inner walls 23 of the die 21, and the punch 31 is pushed into this space during press working. A pad 25 is accommodated in a space between the inner walls 23 of the die 21.

  The inner wall 23 of the die 21 is connected to the plate pressing surface 22 via the die shoulder 24. The contour shape of the cross section of the die shoulder 24 is an arc shape. The plate pressing surface 22, the inner wall 23, and the die shoulder 24 of the die 21 extend along the longitudinal direction of the frame component 1 to be molded. The die shoulder 24 includes a region 24a that is curved in a concave shape in a part of the extending direction. This concavely curved region 24a is provided in a region corresponding to the contracted flange forming portion 4 of the frame component 1 shown in FIG. 1B. The die shoulder 24 includes a straight region 24b and a region 24c curved in a convex shape in a region other than the region 24a curved in a concave shape. The straight region 24b of the die shoulder 24 is provided in a region corresponding to the linear forming portion 6 of the frame component 1 shown in FIG. 1B. The area | region 24c which curves to the convex shape of the die shoulder 24 is provided in the area | region corresponding to the stretch flange molding part 5 of the frame component 1 shown to FIG. 1B.

  In the punch 31, the shape of the top plate portion 3 of the frame component 1 shown in FIG. 1B is formed. The punch 31 has a tip surface 32, a side surface 33, and a punch shoulder 34. The front end surface 32 of the punch 31 is connected to the side surface 33 of the punch 31 through the punch shoulder 34. The contour shape of the cross section of the punch shoulder 34 is an arc shape. The front end surface 32, the side surface 33, and the punch shoulder 34 of the punch 31 extend along the longitudinal direction of the frame component 1 to be molded. The punch shoulder 34 includes a region 34a that is curved in a convex shape in a part of the extending direction. The region 34 a of the punch shoulder 34 that curves into a convex shape is provided at a position corresponding to the region of the die shoulder 24 that curves into a concave shape. The punch shoulder 34 includes a straight region 34b and a concave region 34c in a region other than the convex region 34a. The straight region 34 b of the punch shoulder 34 is provided at a position corresponding to the straight region 24 b of the die shoulder 24. A region 34 c of the punch shoulder 34 that curves into a concave shape is provided at a position corresponding to the region 24 c of the die shoulder 24 that curves into a convex shape.

  The blank holder 41 extends along the longitudinal direction of the frame component 1. The blank holder 41 has a shape corresponding to the plate pressing surface 22 of the die 21. During the press working, the workpiece is sandwiched between the blank holder 41 and the die 21. The blank holder 41 has edges at both ends of the blank holder 41. In the following, the edge of the blank holder 41 refers to the edge on the punch 31 side of both edges of the blank holder 41, and its reference numeral is 42.

[Shrink flange forming part]
FIG. 4 is a diagram showing a state in the middle stage of molding by the press device of the first embodiment, and shows a IV-IV cross section in FIG. 3. That is, FIG. 4 shows a cross section of a region 24 a that is curved in a concave shape of the die shoulder 24 and a region 34 a that is curved in a convex shape of the punch shoulder 34. This region is a region where the shrinkage flange forming portion 4 of the frame component 1 shown in FIG. 1B is formed. In this region, the distance L1 (mm) between the die shoulder boundary line 26 of the die shoulder 24 and the edge 42 of the blank holder 41 is preferably small. This is because the workpiece S is sandwiched between the blank holder 41 and the die 21 until just before the molding bottom dead center to suppress the generation of wrinkles. The distance L1 refers to the horizontal distance of the press device. The same applies to distances L2 to L4 described later.

  FIG. 5 is an enlarged cross-sectional view of the vicinity of the die shoulder in FIG. The die shoulder boundary line 26 of the die shoulder 24 is a line defined by connecting an R stop (R end) on the plate pressing surface 22 side of the die shoulder 24 in the extending direction of the die shoulder 24. And the border of the die shoulder 24. The same applies to the linearly formed portion and the stretch flange formed portion described later. The same applies to a second embodiment described later.

  A preferable lower limit of the distance L1 is zero. That is, this is a case where the horizontal position of the die shoulder boundary line 26 of the die shoulder 24 and the edge 42 of the blank holder 41 coincide. In this case, the workpiece S is sandwiched between the die 21 and the blank holder 41 until just before the molding bottom dead center. Therefore, the wrinkles generated in the contracted flange forming portion 4 of the frame part 1 can be most effectively suppressed.

  Further, the edge 42 of the blank holder 41 may face not only the die shoulder boundary line 26 of the die shoulder 24 but also the die shoulder 24. Furthermore, the edge 42 of the blank holder 41 may exist on the inner side (on the punch 31 side) than the inner wall 23 of the die 21 as long as it does not interfere with the punch 31. Even in this case, the workpiece S is sandwiched between the die 21 and the blank holder 41 until just before the bottom dead center of molding. However, in this case, the effect of suppressing wrinkles does not change compared to the case where the distance L1 is zero. Even if the edge 42 of the blank holder 41 exists on the inner side (punch 31 side) of the die shoulder boundary line 26 of the die shoulder 24, the workpiece S cannot be sandwiched because there is no opposing plate pressing surface 22. Because.

[Linear forming part]
FIG. 6 is a view showing an initial state of molding by the press apparatus of the first embodiment, and shows a VI-VI cross section in FIG. 3. That is, FIG. 6 shows a cross section of the straight region 24 b of the die shoulder 24 and the straight region 34 b of the punch shoulder 34. This region is a region where the linear forming portion 6 of the frame component 1 shown in FIG. 1B is formed. In this region, the distance L2 (mm) between the die shoulder boundary line 26 of the die shoulder 24 and the edge 42 of the blank holder 41 is wider than the distance L1. This reduces the amount of springback at the end of the vertical wall portion of the molded frame part. This point will be described with reference to FIG.

  FIG. 7 is a view showing a state in the middle stage of molding by the press device of the first embodiment, and shows a VI-VI cross section in FIG. 3. As shown in FIG. 7, when the vertical wall portion of the frame part is formed, the end S1 of the workpiece S formed in the linear forming part 6 of the frame part 1 is formed in the shrink flange forming part shown in FIG. Compared with the end portion of the workpiece S to be processed, the blank holder 41 and the die 21 come out at an early stage of press working. In this case, the end portion S1 of the workpiece S formed in the linear forming portion 6 rises in the direction of the arrow in FIG. Thereby, the amount of bending of the end S1 of the workpiece S thereafter becomes an angle θ2 smaller than the angle θ1 shown in FIG. 2B. As a result, the amount of bending back of the end S1 of the workpiece S due to the side surface 33 of the punch 31 and the inner wall 23 of the die 21 is reduced. Therefore, the residual stress generated at the end of the vertical wall portion of the molded frame part is reduced. As a result, the amount of spring back at the end of the vertical wall is reduced.

  In addition, as mentioned above, in the process of the linear shaping | molding part 6 and the stretch flange shaping | molding part 5 of the shape | molded flame | frame component 1, material does not collect from a peripheral area | region. Accordingly, wrinkles are unlikely to occur in the region other than the contracted flange molded portion 4. Therefore, the area where the workpiece S is sandwiched between the die 21 and the blank holder 41 during processing may be small. From the viewpoint of suppressing wrinkles, the blank holder 41 may not be provided in a region other than the contracted flange molded portion 4. However, from the viewpoint of the stability of the press working, it is preferable that the blank holder 41 is provided also in the region other than the contracted flange molded portion 4.

  When a high-strength work material having a tensile strength of 440 MPa or more is pressed, the amount of springback tends to increase in a region of 10 mm or more from the tip of the end of the vertical wall portion of the frame part. Therefore, when processing a high-strength workpiece, the distance L2 between the die shoulder boundary line 26 of the die shoulder 24 and the edge 42 of the blank holder 41 in the region other than the region 24a curved into the concave shape of the die shoulder 24 is It is preferable that it is 10 mm or more. More preferably, it is 15 mm or more. When the distance L2 is 10 mm or more, when the end portion of the workpiece is processed, the workpiece is removed early from between the blank holder and the die. Therefore, for the reasons described above, the amount of spring back at the end of the vertical wall portion of the frame part is reduced.

  Further, when a workpiece having a plate thickness of 2.3 mm or more is pressed, the amount of springback tends to increase in a region of 10 mm or more from the tip of the end of the vertical wall portion of the frame part. In this case, in the same manner as described above, the distance L2 between the die shoulder boundary line 26 of the die shoulder 24 and the edge 42 of the blank holder 41 is 10 mm or more in the region other than the region 24a curved in the concave shape of the die shoulder 24. Is preferred. If the plate thickness is less than 2.3 mm, the entire vertical wall portion of the frame part is likely to spring back. Therefore, even if the amount of spring back at the end of the vertical wall portion is reduced, a frame component with the desired dimensional accuracy can be obtained. It's hard to be done. Moreover, if the plate | board thickness of a workpiece is larger than 6.0 mm, since the rigidity of a workpiece is high, the edge part of a vertical wall part does not spring back easily.

[Stretch flange forming part]
In the region 24c curved in the convex shape of the die shoulder 24 and the region 34c curved in the concave shape of the punch shoulder 34 shown in FIG. In this region, the distance between the die shoulder boundary line 26 of the die shoulder 24 and the edge 42 of the blank holder 41 is not particularly limited. As described above, in this region, the spring back amount of the end portion 7 of the frame component 1 shown in FIG. 1B is small, and furthermore, wrinkles are not easily generated. However, for example, when the radius of curvature of the region 24 c that curves into the convex shape of the die shoulder 24 is large, the amount of springback at the end 7 of the frame part 1 increases as in the case of the straight region 24 b of the die shoulder 24. In such a case, as shown in FIGS. 6 and 7, the distance L2 between the die shoulder boundary line 26 of the die shoulder 24 and the edge 42 of the blank holder 41 is made larger than the distance L1. On the other hand, the distance L2 between the die shoulder boundary line 26 of the die shoulder 24 and the edge 42 of the blank holder 41 may be reduced in order to stably perform the press working. In short, in this region, the distance L2 between the die shoulder boundary line 26 of the die shoulder 24 and the edge 42 of the blank holder 41 is appropriately set.

  In the press device 10 according to the first embodiment shown in FIG. 3, the die shoulder 24 includes a region 24 a that is curved in a concave shape, a linear region 24 b, and a region 24 c that is curved in a convex shape. However, the die shoulder 24 of the press apparatus 10 is not limited to the case shown in FIG. As long as the die shoulder 24 has a concavely curved region 24a, the die shoulder 24 only needs to have one of a linear region 24b and a convexly curved region 24c in the other region. In short, the straight region 24b and the convex region 24c may be formed on the die shoulder 24 in accordance with the shape of the frame component.

  Moreover, in the press apparatus 10 shown in FIG. 3, the case where the blank holder 41 was arrange | positioned adjacent to the both sides of the punch 31 was illustrated. However, the arrangement of the blank holder 41 is not limited to the case shown in FIG. In the case of reducing the amount of spring back only at one end of the frame part, the blank holder 41 may be arranged only on one side of the punch 31. In short, the arrangement of the blank holder 41 may be selected according to the shape of the frame component.

[Second Embodiment]
In the first embodiment, as shown in FIG. 1B, the press device that presses the frame component 1 including the contracted flange forming portion 4 and the stretch flange forming portion 5 that are curved in the vertical direction has been described. 2nd Embodiment demonstrates the press apparatus which press-processes frame components containing the shrinkage flange shaping | molding part curved in a horizontal direction, and an elongate flange shaping | molding part. The press apparatus of the second embodiment is based on the configuration of the press apparatus of the first embodiment. Below, the description which overlaps with 1st Embodiment is abbreviate | omitted suitably.

[Press-formed product]
FIG. 8 is a perspective view of a frame component manufactured by the press device according to the second embodiment. As shown in FIG. 8, the frame component 51 of the second embodiment has a groove-shaped cross section and includes a vertical wall portion 52 and a top plate portion 53. The frame part 51 has a flange flange part 54 that is partially contracted. In FIG. 8, the frame component 51 exemplifies a case where the frame component 51 has the stretched flange molded portion 55 and the linear molded portion 56 in a region other than the contracted flange molded portion 54. Since the frame part 51 is curved in the horizontal direction, one side of the curved region is a contracted flange molded part 54 and the other is a stretched flange molded part 55.

  Also in the frame component 51 of the second embodiment, the region where the springback amount is large is the same as that of the first embodiment. That is, in the contracted flange molding portion 54 and the stretch flange molding portion 55 of the frame part 51, the spring back amount of the end portion 57 of the vertical wall portion 52 is small, and in the linear molding portion 56, the spring of the end portion 57 of the vertical wall portion 52 is small. The back amount is large. Below, the press apparatus which manufactures such a frame component 51 from a workpiece is demonstrated.

[Pressing equipment]
FIG. 9 is a view showing an intermediate state of press forming by the press apparatus of the second embodiment, and shows a cross section IX-IX in FIG. 8. In this region, one is a region for forming the shrinkage flange forming portion 54 (the region on the right side in FIG. 9), and the other is a region for forming the stretched flange forming portion 55 (the region on the left side in FIG. 9). In the region where the contracted flange forming portion 54 of the frame part 51 shown in FIG. 8 is formed, the distance L3 (mm) between the die shoulder boundary line 63 of the die shoulder 62 and the edge 82 of the blank holder 81 is preferably small. More preferably, the horizontal positions of the edge 82 of the blank holder 81 and the die shoulder boundary line 63 of the die shoulder 62 coincide with each other. This is because during processing of the workpiece S, the workpiece S is sandwiched between the blank holder 81 and the die 61 to suppress the generation of wrinkles.

  On the other hand, in the region where the stretch flange forming portion 55 of the frame component 51 shown in FIG. 8 is formed, the distance L4 (the distance L4 between the die shoulder boundary 63 of the die shoulder 62 and the edge 82 of the blank holder 81 is the same as in the first embodiment. mm) is not particularly limited as described above. In short, the distance L4 between the die shoulder boundary line 63 of the die shoulder 62 and the edge 82 of the blank holder 81 is appropriately set.

  When forming the linear forming portion 56 of the frame component 51 shown in FIG. 8, the distance (mm) between the die shoulder boundary 63 of the die shoulder 62 and the edge 82 of the blank holder 81 is the same as in the first embodiment. It is wider than the distance L3 (see FIG. 9). Thereby, even if the frame component 51 of the second embodiment is molded, the amount of spring back of the end portion 57 of the vertical wall portion 52 is reduced.

  In the above description, as shown in FIG. 8, the press device for manufacturing the frame component in which the one side is the shrink flange forming portion 54 and the other is the stretch flange forming portion 55 in the region curved in the horizontal direction of the frame component has been described. . On the other hand, the press device of this embodiment can also produce a frame part that is the same molded part on both sides in a region that is curved in the horizontal direction. Such a component is, for example, a frame component that shrinks on both sides in a curved region of the frame component and is a flange-formed part. In short, as described above, if the distance between the die shoulder boundary line and the edge of the blank holder is set corresponding to each molding part, the amount of springback at the end of the molded vertical wall part can be reduced.

  The press device for manufacturing the automobile frame component has been described above. However, the press apparatus of this embodiment can be applied to manufacturing other than frame parts. In short, the press device of the present embodiment can be applied to any press-formed product that has a groove-shaped cross section and partially has a flange-formed flange part. Such press-molded products include, for example, suspension parts such as Rr lower arms and upper arms.

  The press apparatus of the present invention is useful for the manufacture of a press-formed product having a groove-shaped cross section and partially shrinking a flange forming portion. In particular, the press device of the present invention is useful for the production of press-molded products that are molded into automobile frame parts and suspension parts.

1, 51: Frame parts (press-molded products),
2, 52: vertical wall portion, 3, 53: top plate portion,
4, 54: shrinkage flange molding part, 5, 55: stretch flange molding part,
6, 56: Straight line forming part, 7, 57: End of vertical wall part, 10: Press device,
21, 61: Die, 22: Plate pressing surface, 23: Die inner wall, 24, 62: Die shoulder,
24a: a region curved in a concave shape on the die shoulder, 24b: a linear region on the die shoulder,
24c: Die shoulder curved region 25: Pad,
26, 63: die shoulder boundary line, 31, 71: punch,
32: Punch tip surface, 33: Punch side surface, 34, 72: Punch shoulder,
34a: a region curved in a convex shape of the punch shoulder, 34b: a straight region of the punch shoulder,
34c: a region curved in a concave shape on the punch shoulder, 41, 81: a blank holder,
42, 82: Edge of blank holder, S: Work material,
S1: End part of workpiece, L1 to L4: Distance between punch shoulder and blank holder

Claims (8)

Punch and
A blank holder disposed adjacent to the punch;
A die including a die shoulder and a plate pressing surface, and a die in which a part of the die shoulder is curved in a concave shape along the extending direction of the die shoulder,
The distance in the horizontal direction between the die shoulder boundary line defined by the R stop on the plate pressing surface side of the die shoulder and the edge of the blank holder in a region other than the concavely curved region of the die shoulder , the said die shoulder boundary line in the region where the curved concave die shoulder, widely than the distance in the horizontal direction and the edge of the blank holder,
In a region other than the concavely curved region of the die shoulder, a horizontal distance between the die shoulder boundary line and the edge of the blank holder is 10 mm or more . The press device according to claim 1,
The press apparatus in which the die shoulder boundary line coincides with the edge of the blank holder in the horizontal direction in the concavely curved region of the die shoulder. The press device according to claim 1 or 2,
The press apparatus includes a pad arranged to face the punch. The press device according to any one of claims 1 to 3 ,
The die shoulder further includes a region curved in a convex shape. The press device according to any one of claims 1 to 4 ,
The said blank holder is a press apparatus arrange | positioned adjacent to the both sides of the said punch. In a method for producing a press-formed product having a groove-shaped cross section, comprising a top plate portion, and a vertical wall portion connected to the top plate portion, and having a partially contracted flange portion,
The manufacturing method includes:
A preparation step of preparing a workpiece made of a metal plate;
A pressing step of forming the workpiece into the press-formed product by pressing,
In the pressing step,
A die including a punch, a blank holder disposed adjacent to the punch, a die shoulder and a plate pressing surface, and a shape of the shrinkage flange portion of the press-formed product in a partial region of the die shoulder Using a die formed with a reflecting shape,
A die shoulder boundary line defined by an R-stop on the plate pressing surface side of the die shoulder in a region other than a region in which a shape reflecting the shape of the shrinking flange portion of the die shoulder is formed, and an edge of the blank holder And the horizontal distance between the die shoulder boundary line and the edge of the blank holder in the region where the shape reflecting the shape of the shrink flange portion of the die shoulder is formed. distance widely than,
In a region other than the region where the shape reflecting the shape of the contracted flange portion of the die shoulder is formed, the distance in the horizontal direction between the die shoulder boundary line and the edge of the blank holder is 10 mm or more . Manufacturing method of press-molded products. It is a manufacturing method of the press-formed product according to claim 6 ,
The method for producing a press-formed product, wherein the workpiece has a tensile strength of 440 MPa or more. A method for producing a press-formed product according to claim 6 or 7 ,
The method for manufacturing a press-formed product, wherein the workpiece has a plate thickness of 2.3 mm or more.

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