JP7243670B2 - METHOD FOR MANUFACTURING PRESS PARTS, AND METAL PLATE - Google Patents

Description

The present invention has a cross section such as a hat-shaped cross section or an L-shaped cross section having at least a top plate portion, a side wall portion continuing to the top plate portion, and a flange portion, and in the longitudinal direction that is the direction intersecting the above cross section Also, the present invention relates to a method of manufacturing a pressed part having a shape of a pressed part having one or more curved portions that are concave on the side wall side (width direction) when viewed from above.
Here, in this specification, the top view refers to the case where the top plate and the like are seen from the plate thickness direction of the top plate.

Many stamped parts for automobiles and home appliances are made by deforming flat metal plates into various shapes. When mass-producing pressed parts, press forming (pressing) is widely used in which a metal plate is deformed using a press machine and a die. Since a metal plate is generally flat before processing, the metal plate must expand and contract according to the three-dimensional shape in order to transform it into a complicated three-dimensional shape. However, the more complicated the shape of the press part becomes, the more difficult it becomes to give the metal plate an expansion and contraction matching the three-dimensional shape. In particular, when a difficult-to-form member made of a high-strength steel plate or an aluminum alloy plate having a tensile strength of 590 MPa or more and having inferior ductility and Lankford value is used as the metal plate, the above difficulties are likely to occur.

If the metal plate is not stretched and contracted in accordance with the three-dimensional shape, molding defects such as cracks and wrinkles occur in the metal plate. In other words, when a metal plate is deformed into a three-dimensional shape, the metal plate has no choice but to stretch in areas where the length of the metal plate is insufficient and the shortfall cannot be compensated for by the surroundings, and the metal plate is stretched beyond its own ductility. Cracking occurs when On the other hand, when the metal plate must be shortened when deformed into a three-dimensional shape, or when the metal plate is excessively inflowed from the surroundings, wrinkles tend to occur.
As an example of a part shape that is difficult to press-form, a cross section having a top plate portion, a side wall portion continuing to the top plate portion, and a flange portion formed continuously to the side wall portion, and having a longitudinal direction of There are press-formed parts having one or more curved shapes in the width direction when viewed from above.

When such a complicated part shape is press-molded from a flat metal plate, the pressed part is likely to crack or wrinkle because tensile deformation or compression deformation occurs during molding.
Here, when a product having a complicated shape as described above is press-molded from a metal plate, for example, bending using a mold consisting of a punch, die, and pad, punch, die, and blank holder (wrinkles) Drawing is performed using a die consisting of a presser. In the case of bending, wrinkles are generated in the flange portion, which causes poor molding. In addition, in the case of drawing, wrinkles are generated in the top plate portion, which causes molding defects.
As a countermeasure for this problem, for example, there is a curved part manufacturing method and a curved part manufacturing apparatus described in Patent Document 1.

Japanese Patent No. 5733475

In the case of draw molding, tension and compression deformation of the flange portion can be suppressed because the flange surface is constrained by the die and blank holder. However, in the case of foam molding or pad foam molding, since the flange portion is not constrained, it may be affected by tensile or compressive deformation and wrinkles may occur. Therefore, it may not be possible to suppress the occurrence of wrinkles unless the tensile and compressive deformation of the metal plate that occurs throughout the part shape is taken into consideration.

As for foam molding, although the mold structure is simple and low cost, wrinkles are likely to occur not only on the flange but also on the top plate surface because neither the top plate nor the flange are constrained. For this reason, conventionally, foam molding is not mainly performed, and pad foam molding, draw molding, and their combined processes are used.
Here, in the method described in Patent Document 1, since the top plate portion is constrained by the pad and the flange portion is also constrained by the blank holder, tensile and compressive deformation of both the top plate portion and the flange portion can be suppressed. I can. However, in addition to the usual squeezing process, it is necessary to constrain the material with a pad, resulting in poor productivity. Also, the cost of the mold is high.

The present invention has been made by paying attention to the above points, and is a pressed part having one or more curved portions that are concavely curved toward the side wall portion side (width direction) along the longitudinal direction when viewed from above. It is an object of the present invention to suppress the occurrence of wrinkles on the concave side of a curved portion by a simple means during press molding into a shape.

The inventor studied wrinkles generated on the convex side of the curved portion and wrinkles generated on the concave side, and found out the mechanism of wrinkle generation on the convex side of the curved portion and the generation mechanism of wrinkles generated on the concave side. I got the knowledge that it is different from The present invention is made based on such findings.

That is, in order to solve the problem, one aspect of the present invention provides a top plate portion, a side wall portion continuous to at least one of the top plate portion in the width direction via a first bent portion, and a second bent portion on the side wall portion. 1 or 2 curved portions that have a cross section having a flange portion that is continuous through the section and that are curved concavely toward the side wall portion side in a top view along the longitudinal direction that is the direction intersecting the cross section In the method of manufacturing a pressed part for forming a metal plate into the shape of the pressed part having the above, the second A first bead extending along the longitudinal direction is formed at a position to be a bent portion, and at least the top plate portion and the first bead are formed in a region to be the curved portion forming the first bead. a preforming step including a step of forming a second bead extending along the longitudinal direction at a position corresponding to at least one of the bent portions; and forming the metal plate after the preforming step into the shape of the pressed part. and a part molding process.

Another aspect of the present invention is a top plate portion, a side wall portion that is continuous with at least one of the top plate portion in the width direction via a first bent portion, and a side wall portion that is continuous with the side wall portion via a second bent portion. a press part having a cross section having a flange portion and having one or more curved portions curved concavely toward the side wall portion in a top view along a longitudinal direction that is a direction intersecting the cross section. (2) a method of manufacturing a pressed part for forming a metal plate, wherein the metal plate is provided with a position that becomes the second bent portion with respect to the side wall portion that is the concave portion in at least a region that becomes the curved portion; and a second bead extending along the longitudinal direction at a position corresponding to at least one of the top plate portion and the first bent portion. a preforming step having a step of forming at least one bead selected from the beads, and the metal plate after the preforming step is restrained with a pad at a position to be the top plate portion, and the press part and a part forming step for forming into a shape.

Another aspect of the present invention is a top plate portion, a side wall portion that is continuous with at least one of the top plate portion in the width direction via a first bent portion, and a side wall portion that is continuous with the side wall portion via a second bent portion. a press part having a cross section having a flange portion and having one or more curved portions curved concavely toward the side wall portion in a top view along a longitudinal direction that is a direction intersecting the cross section. 2, a metal plate for press forming, which extends along the longitudinal direction at a position that becomes the second bent portion with respect to the side wall portion that is at least the area that becomes the curved portion and is the recessed side wall portion. extending along the longitudinal direction to a position corresponding to at least one of the top plate portion and the first bending portion with respect to the existing first bead and the area serving as the curved portion forming at least the first bead. and a second bead present.

Another aspect of the present invention is a top plate portion, a side wall portion that is continuous with at least one of the top plate portion in the width direction via a first bent portion, and a side wall portion that is continuous with the side wall portion via a second bent portion. a press part having a cross section having a flange portion and having one or more curved portions curved concavely toward the side wall portion in a top view along a longitudinal direction that is a direction intersecting the cross section. In addition, a metal plate for press-molding while restraining the top plate portion with a pad, the second bending portion and and a second bead extending along the longitudinal direction at a position corresponding to at least one of the top plate portion and the first bent portion. The gist is that at least one bead selected from two types of beads is formed.

According to the aspect of the present invention, for example, the second bead relaxes the compressive force along the longitudinal direction in the flange portion due to the material wrapping around the flange portion on the concave side of the curved portion generated during molding, The first bead improves the shape rigidity at the position on the concave side of the curved portion, making it possible to suppress buckling during molding on the concave side of the curved portion. Therefore, in the embodiment of the present invention, it is possible to efficiently suppress the occurrence of wrinkles in the side wall portion and the flange portion on the concave side of the curved portion without necessarily constraining the flange portion with a mold for press molding.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the press part shape which concerns on embodiment based on this invention, (a) is a perspective view, (b) is sectional drawing. It is a figure which shows the process example of the manufacturing method of the press part which concerns on embodiment based on this invention. It is a perspective view explaining the 1st bead and the 2nd bead which are fabricated at a preforming process. It is a schematic diagram seen from the front showing an example of a bead after a preforming process. It is a figure explaining the molding example in a component molding process. FIG. 10 is a schematic plan view from the perspective of information explaining the reason why wrinkles are generated on the concave side of the curved portion; It is a figure which shows the example of wrinkle generation. It is a top view for demonstrating the evaluation method in an Example. It is a figure explaining evaluation.

Next, embodiments of the present invention will be described with reference to the drawings.
(Press part shape)
The shape of the pressed part after press forming, which is the target of this embodiment, includes at least the top plate portion and the side wall portion that is continuous to at least one of the left and right sides of the top plate portion through the first bent portion, and the side wall portion has the second bent portion. It has a cross-sectional shape such as a hat-shaped cross section or an L-shaped cross section having a continuous flange portion. Furthermore, the shape of the press part has one or more curved portions that are curved in the width direction along the longitudinal direction when viewed from above, at one or more locations in the longitudinal direction, which is the direction that intersects the cross section. Shape. Note that the curved portion may be determined by determining whether or not the top plate portion is curved in the width direction.
Here, the present embodiment is a technology suitable for manufacturing pressed parts using a metal plate made of a difficult-to-form member with inferior ductility and Lankford value, such as a high-tensile steel plate or an aluminum alloy plate having a tensile strength of 590 MPa or more. be.

In the present embodiment, the shape of the desired pressed part 1 after press molding is a hat-shaped cross section as shown in FIG. A case of molding into a component shape will be described as an example. That is, in the present embodiment, as shown in FIG. 1, the target press part shape has a hat-shaped cross section and two locations along the longitudinal direction, that is, the top plate portion 1A is curved in the width direction when viewed from the top. A case where there is a curved portion 10 is illustrated. In the example of FIG. 1A, the lower side wall portion 1B is the concave side wall portion in the left curved portion, and the upper side wall portion 1B is the concave side wall portion in the right curved portion.
However, in this embodiment, the bending portion 10 may be provided at one location, or the bending portions 10 may be provided at three or more locations. Further, there may be two or more curved portions 10, and two adjacent curved portions 10 may be curved in the same direction.
Note that the dimensions shown in FIG. 1(b) are the dimensions in the example, and do not limit the present invention.

(composition)
The manufacturing method of the pressed part 1 of this embodiment comprises a preforming step 2 and a part forming step 3, as shown in FIG.

<Preforming step 2>
The preforming step 2 is a step of preliminarily forming the metal plate before the main forming to obtain a metal plate for the main forming in which wrinkles are less likely to occur.
In the preforming step 2, as shown in FIG. 3, the flat metal plate 4 is formed with the second bent portion 1e (see FIG. 1), the top plate portion A press molding process is provided to form a second bead 4b extending along the longitudinal direction at a position corresponding to at least one of 1A and the first bent portion 1d.

In the preforming step 2 of the present embodiment, as shown in FIG. 3, the flat metal plate 4 is provided with first beads extending along the longitudinal direction over the entire positions of the left and right second bent portions 1e. 4a and forming second beads 4b extending in the longitudinal direction over the entire positions of the left and right first bent portions 1d. An example of the first bead 4a and the second bead 4b is shown in FIG. This example is an example in which the first bead 4a and the second bead 4b are formed of full beads.
Here, the first bead 4a and the second bead 4b of the present embodiment have a shape extending in the longitudinal direction (longitudinal direction of the top plate portion 1A) in which the cross section of the bent shape intersects the cross section. ing. The first bead 4a is a full bead, a half bead having a stepped cross-section, or the like.

The second bent portion 1e corresponds to the cross section of the ridgeline portion 1E formed between the side wall portion 1B and the flange portion 1C. This ridge line portion 1E is curved upward to form a concave shape. The first bent portion 1d corresponds to the cross section of the ridgeline portion 1D formed between the top plate portion 1A and the side wall portion 1B. The ridgeline portion 1D is curved upward to form a concave shape.
On the molding surfaces of the upper mold (die) and the lower mold (punch), which constitute the mold used in the preforming step 2, along the positions of the second bent portion 1e and the first bent portion 1d, respectively, A bead shape is formed following the first bead 4a and the second bead 4b extending along the longitudinal direction. The positions at which the first bead 4a and the second bead 4b are formed are positions in the part forming process 3 where they can come into contact with the punch shoulder ridge and the die shoulder ridge of the mold in the part forming process 3.
Then, in the preforming step 2, the metal plate 4 is press-formed using the upper mold and the lower mold, and the metal plate 4 having the first bead 4a and the second bead 4b extending along the longitudinal direction. do.

<Regarding Formation of First Bead 4a>
The position where the first bead 4a is formed is a position where it can come into contact with the die shoulder ridge line of the mold in the component molding step 3. As shown in FIG.
The first bead 4a preferably has a concave shape (a shape convex downward) in the same direction as the concave direction of the second bent portion 1e (see FIG. 4).
The bead height of the first bead 4a is preferably at least one time the thickness of the metal plate 4. As shown in FIG. It is preferably twice or more. The upper limit of the height of the first bead 4a is 30 mm.

In this embodiment, the two bending portions 10 are provided, and the bending directions of the two bending portions 10 are different from each other. That is, since both the left and right side wall portions 1B are concave sides of the curved portion 10, the first beads 4a are individually formed along the left and right second bent portions 1e.
When all the curved portions 10 are curved in the same direction, the first bead 4a is formed only along the second curved portion 1e on the concave side wall portion 1B side of the curved portion 10. good. However, even in this case, the first bead 4a may be formed on the opposite side.
In the above description, regardless of the position of the curved portion 10, the first bead 4a is formed along the entire position of the ridgeline portion 1E formed between the side wall portion 1B and the flange portion 1C. exemplified.

The first bead 4a may be partially formed along the ridgeline portion 1E formed between the side wall portion 1B and the flange portion 1C. However, it is preferable to form so as to include at least the ridge line portion 1E located on the side of the side wall portion 1B, which is a region to be the curved portion 10 and has a concave curve.
That is, the first bead 4a may be formed only on the ridge line portion located on the side of the side wall portion 1B where the curved portion 10 is formed and the curved portion is concave.

At this time, it is not necessary to form the first bead 4a on all of the ridgeline portions 1E located on the side of the side wall portion 1B where the curve is concave and which is the area to be the curved portion 10 . For example, on the side of the side wall portion 1B which is a region that becomes the curved portion 10 and is concave, there is a plate portion that is presumed to cause wrinkles in the flange portion 1C when the metal plate 4 made of a flat plate is press-formed into the shape of the press part. You may make it form the 1st bead 4a partially only in the area|region which contains.
The process of obtaining the plate portion where wrinkles are estimated to occur may be performed by molding analysis using a computer, or may be actually performed by press molding.
Further, for simplicity, the concave side of the curved portion 10 where the radius of curvature of the curved portion 10 is equal to or greater than a preset value may be set as the plate portion where wrinkles are estimated to occur.

<Second bead 4b>
It is not necessary to form the second bead 4b over the entire area of the ridgeline portion 1D formed between the top plate portion 1A and the side wall portion 1B. The second bead 4b may be formed so as to extend along the longitudinal direction at a position to be the first bent portion 1d with respect to the region to be the curved portion 10 forming at least the first bead 4a. The second bead 4b is formed along at least one of the left and right first bent portions 1d. It is preferable that the second bead 4b be provided on the first bent portion 1d side of the concave side wall portion 1B in the area that becomes the curved portion 10 .

Moreover, it is preferable that the second bead 4b has a shape that protrudes in the same direction as the protruding direction of the first bent portion 1d (a shape that protrudes upward in cross section).
Moreover, it is preferable that the bead height of the second bead 4b is equal to or greater than the plate thickness of the metal plate 4 described above. The upper limit of the bead height of the second bead 4b is 30 mm.
Also, the second bead 4b may be formed at a position that forms the top plate portion 1A separately from or together with the position that forms the first bent portion 1d. However, it is preferable to provide the second bead 4b at a position that becomes the first bent portion 1d.
Here, the second bead 4b is preferably provided on the convex side of the curved portion 10, but may be provided on the concave side.

<Parts molding process 3>
The part forming process 3 is a main forming process in which the metal plate 4 processed in the preforming process 2 is formed into a target pressed part shape.
In the part forming step 3, upper and lower molds having forming surfaces 20 and 21 as shown in FIG. is press part 1.
FIG. 5 illustrates a case of adopting pad foam molding having a pad 22 for pressing the top plate portion 1A. That is, this example illustrates the case of bending. In the component forming step 3, foam forming in which the top plate portion 1A is not pressed by the pad 22 may be adopted.

(Other operations)
In this embodiment, in the preforming step 2, as preforming, the metal plate 4 is provided with a first bead 4a and a second bead 4b (FIG. 3).
The metal plate 4 in the preforming step 2 is provided with the first beads 4a along the longitudinal direction, so that the shape rigidity in the longitudinal direction increases at the portion where the first beads 4a are formed and in the vicinity thereof. Furthermore, the metal plate 4 in the preforming step 2 can be restrained from being drawn into the concave side of the curved portion 10 by providing the second bead 4b.

Next, when the metal plate 4 after the preforming step 2 is pressed in the part forming step 3 to form a hat-shaped cross section having a curved portion 10 curved in the width direction (horizontal direction) in a top view, the bead As a result, the shape rigidity in the longitudinal direction of the side wall portion 1B and the flange portion 1C on the concave side of the curved portion 10 is increased, and the second bead 4b suppresses the material from being pulled into the concave side of the curved portion 10 during molding. Therefore, the occurrence of wrinkles due to buckling on the concave side of the bending portion 10 is suppressed.

The operation and the like of this embodiment will be further described in detail with reference to FIG.
The inventor studied the mechanism by which wrinkles are generated in the side wall portion 1B and the flange portion 1C on the concave side of the curved portion 10, and obtained the following findings. That is, while the metal plate is being formed into the intended shape of the pressed part, on the concave side of the curved portion 10, the material of the top plate portion 1A and the side wall portion moves (wraps around) in the M1 direction, so that the material moves into the curved portion. 10 is pulled into the flange portion 1C on the concave side, and a compressive force along the longitudinal direction is generated at the end portion of the flange.
As a result, conventionally, the flange portion 1C on the concave side of the curved portion 10 cannot withstand the compressive force during molding, and the surface of the flange portion 1C buckles, causing wrinkles (see FIG. 7).

On the other hand, in the present embodiment, the first bead 4a and the second bead 4b are applied to the metal plate 4 to be press-molded in the part forming process 3, and then the press molding in the part forming process 3 is performed. do. Therefore, in the present embodiment, the second bead 4b reduces the compressive force during press molding in the component molding step 3, and suppresses movement of the material (rotation of the material) toward the concave side of the curved portion 10. . Further, the first bead 4a press-forms into the desired shape of the pressed part in a state of high longitudinal shape rigidity in the area that will become the flange portion 1C. As a result, buckling during molding is suppressed, and wrinkling of the flange portion 1C on the concave side of the curved portion 10 is suppressed.

Further, the first bead 4a formed in the preforming step 2 is erased by being overlapped with the edge line 1E in the press forming in the part forming step 3. The second bead 4b formed in the preforming process 2 is also erased by press forming in the component forming process 3 by overlapping with the edge line 1D. It should be noted that the second bead 4b may be left as part of the shape of the part if the shape of the part permits.
As a result, wrinkles can be suppressed without deteriorating the yield and without changing the desired shape of the press part.

Here, when the metal plate 4 is a high-strength steel plate, or the shape of the part is such that the bending portion 10 has a large curvature, and the compression force generated during forming is large, the shape accuracy of the shape of the pressed part is improved. If desired, it is preferable to reduce the range where the first bead 4a is provided as much as possible. In this case, for example, it may be provided in the region of the bending portion 10 .
It should be noted that it is preferable to limit the second bead 4b within the region of the curved portion 10 in consideration of shape accuracy.

(Modification)
In the above embodiment, the second bead 4b is provided together with the first bead 4a.
In the press process in the component molding process, when pressing the top plate portion 1A with a pad such as pad foam molding and press molding, only one of the first bead 4a and the second bead 4b is formed in the preforming process. It is good also as a structure to carry out.
When the top plate portion 1A is restrained and molded into the desired shape of the pressed part, the rotation of the material toward the concave side of the curved portion 10 is suppressed, so one of the first bead 4a and the second bead 4b is omitted. It becomes possible. However, providing both beads 4a and 4b makes it possible to efficiently suppress wrinkles.

(effect)
This embodiment has the following effects.
(1) In the present embodiment, a top plate portion 1A and a side wall portion 1B continuous to at least one of the top plate portion 1A in the width direction via a first bent portion 1d and a second bent portion 1e formed in the side wall portion 1B. A curved portion 10 which has a cross section having a flange portion 1C which is continuous with the flange portion 1C through the cross section and which is curved concavely toward the side wall portion 1B in top view along a longitudinal direction which is a direction intersecting the cross section. Or a method for manufacturing a pressed part 1 in which a metal plate 4 is formed into a pressed part shape having two or more, wherein the side wall portion 1B formed in the metal plate 4 is at least a region that becomes the curved portion 10 and is the concave portion. At least the first bead 4a that forms the first bead 4a extending along the longitudinal direction at the position that becomes the second bent portion 1e with respect to the region that becomes the curved portion 10 that forms the first bead 4a , a preforming step 2 having a step of forming a second bead 4b extending along the longitudinal direction at a position corresponding to at least one of the top plate portion 1A and the first bent portion 1d; and the preforming step and a part forming step 3 for forming the metal plate 4 after 2 into the shape of the pressed part.

According to this configuration, in the metal plate 4, the movement of the material toward the concave side of the curved portion during molding is suppressed, and the shape rigidity of the position on the concave side of the curved portion 10 is improved. Buckling during molding can be suppressed. Therefore, in the present embodiment, wrinkles in the side wall portion 1B and the flange portion 1C on the concave side of the curved portion 10 can be efficiently suppressed without necessarily constraining the flange portion 1C with a mold for press molding. becomes.
Further, according to this configuration, it is possible to adopt foam molding as the press molding in the component molding step 3 .

(2) It is preferable that the first bead 4a be concave in the same direction as the concave direction of the second bent portion 1e.
According to this configuration, the first bead 4a is provided to increase the shape rigidity, and when forming the desired pressed part shape, the first bead 4a is superimposed on the ridgeline portion 1E formed by the second bent portion 1e. Easier to erase.

(3) It is presumed that wrinkles are generated in the flange portion 1C when the metal plate 4 made of a flat plate is press-formed into the shape of the press part on the side of the side wall portion 1B that is the region that becomes the curved portion 10 and is the concave portion. It is preferable to partially form the first bead 4a in a region including the plate portion to be bonded.
With this configuration, it is possible to reduce the area for forming the first bead 4a.

(4) The bead height of the first bead 4a is preferably equal to or greater than the thickness of the metal plate 4 .
According to this configuration, it is possible to more reliably suppress the occurrence of wrinkles.

(5) It is preferable that the second bead 4b is formed only at the position of the first bent portion 1d.
According to this configuration, since the top plate portion 1A is not provided with the second bead 4b, it becomes easy to connect the top plate portion 1A and other components.

(6) The second bead 4b preferably has a shape that protrudes in the same direction as the protruding direction of the first bent portion 1d.
According to this configuration, while suppressing the movement of the material to the concave side of the curved portion 10 during molding to suppress the occurrence of wrinkles on the concave side of the curved portion 10, the second bead is formed when forming the desired press part shape. 4b is superimposed on the ridgeline portion 1D formed by the first bent portion 1d to facilitate erasing.

(7) In the present embodiment, the top plate portion 1A and the side wall portion 1B that is continuous to at least one of the top plate portion 1A in the width direction via the first bent portion 1d and the second bent portion 1e are formed in the side wall portion 1B. A curved portion 10 which has a cross-section having a flange portion 1C which is continuous with the flange portion 1C through the cross-section and which is curved concavely toward the side wall portion 1B in a top view along a longitudinal direction which is a direction intersecting the cross-section. Alternatively, the metal plate 4 for press-molding the metal plate 4 into a press part shape having two or more, and is at least the region that becomes the curved portion 10, and the side wall portion 1B side that is the concave portion is attached to the side of the side wall portion 1B. 2 A first bead 4a extending along the longitudinal direction at a position to be the bent portion 1e, and a region to be the curved portion 10 forming at least the first bead 4a, the top plate portion 1A and A metal plate 4 having a second bead 4b extending along the longitudinal direction at a position corresponding to at least one of the first bent portions 1d is used.

When this metal plate 4 is used, the top plate portion 1A and the side wall portion 1B that is continuous with at least one of the top plate portion 1A in the width direction via the first bent portion 1d and the second bent portion 1e on the side wall portion 1B are formed. A curved portion 10 which has a cross section having a flange portion 1C which is continuous through a section and is curved so as to be concave toward the side wall portion 1B when viewed from above along the longitudinal direction which is the direction intersecting the cross section. When press-molding into a shape of a press part having one or more, wrinkles in the side wall portion 1B and the flange portion 1C on the concave side of the curved portion 10 do not necessarily have to be press-molded by constraining the flange portion 1C with a mold. can be efficiently suppressed.
Here, it is preferable that the first bead 4a be concave in the same direction as the concave direction of the second bent portion 1e.

In addition, when the metal plate 4 made of a flat plate is press-formed into the shape of the press part on the side of the side wall portion 1B that is the region that becomes the curved portion 10 and is the side wall portion 1B, the flange portion 1C or the side wall portion 1B is formed. The first bead 4a may be partially formed in the area including the plate portion where the crease is estimated to occur.
In addition, a second bead 4b extending along the longitudinal direction is formed at a position to be the first bent portion 1d in a region to be the curved portion 10 forming at least the first bead 4a. It may be in the shape of

(8) The method of manufacturing the pressed part 1 described above can be applied even when the metal plate 4 to be press-formed is a high-strength steel plate having a tensile strength of 590 MPa or more.

Next, an example of press molding of the above-described embodiment based on the present invention will be described. In addition, the present invention is not limited to the following examples.
"Applicable materials"
As the metal plate 4, as shown in Table 1, four types of steel plates of 590 MPa class steel plate (590 material), 980 MPa class steel plate (980 material), 1180 MPa class steel plate (1180 material), and 1470 MPa class steel plate (1470 material) are used. Using.
The metal plate 4 was a flat plate with a width W of 240 mm and a length L of 387 mm.

Moreover, as a target press part shape, a shape having a hat-shaped cross section and curved portions 10 at two locations along the longitudinal direction in a top view as shown in FIG. 1 was used.
Then, when the metal plate 4 (blank) of the comparative example and the metal plate 4 (blank) of the example of the present invention were press-molded into the target press part shape, the flange portion 1C on the concave side of the curved portion 10 The wrinkle generation was evaluated.
Table 2 shows the evaluation conditions and evaluation results (moldability).

In Table 2, in Comparative Example (No. 0), the metal plate 4 used was a flat plate material in which beads were not formed.
In addition, in the present invention examples (No. 1 to No. 6), a flat plate material having beads formed according to the present invention was used for the metal plate 4 to be molded.
Specifically, No. 1 is an example in which a first bead 4a (full bead) is formed over the entire area along the left and right second bent portions 1e. Note that the second bead 4b is not formed.
No. 2 is an example in which a second bead 4b (full bead) is formed over the entire area along the left and right first bent portions 1d. Note that the first bead 4a is not formed.

No. 3 forms a first bead 4a (full bead) over the entire area along the left and right second bent portions 1e, and a second bead 4a (full bead) over the entire area along the left and right first bent portions 1d. This is an example in which a bead 4b (full bead) is formed.
No. 4 forms a first bead 4a (full bead) over the entire area along the left and right second bent portions 1e, and a second bead 4a (full bead) over the entire area along the left and right first bent portions 1d. is an example in which a bead 4b (half bead) is formed.

No. 5 forms a first bead 4a (full bead) only at the position on the concave side of the curved portion 10 along the left and right second bent portions 1e, and along the left and right first bent portions 1d, each full area This is an example in which a second bead 4b (full bead) is formed all the way.
No. 6 forms a first bead 4a (full bead) only at the position on the concave side of the curved portion 10 along the left and right second bent portions 1e, and only along the right first bent portion 1d, all over the entire area. This is an example in which a second bead 4b (full bead) is formed all the way.

In Table 2, "FORM" is when foam molding is adopted as press molding. "PADFORM" is press forming, in which form forming is performed in a state where the top plate portion 1A position is pressed with a pad.
The wrinkles were determined by visually confirming the surface properties of the concave side of the curved portion 10 of the molded product, and evaluating the results in three stages of ◯, Δ, and ×.
Specifically, "×" indicates that significant wrinkles occurred, "Δ" indicates that slight wrinkles were formed although no significant wrinkles occurred, and "◯" indicates that no wrinkles occurred at all.

As can be seen from Table 2, in the comparative example, wrinkles occurred in any steel type in the case of form forming when forming a target pressed part shape. In addition, in the comparative example, in pad foam molding that suppresses the top plate portion 1A, wrinkles are improved when the tensile strength of the metal plate 4 is 980 MPa or less, but noticeable wrinkles are observed when the tensile strength of the metal plate 4 is 1180 MPa or more. There has occurred.
On the other hand, No. of the present invention example. 1 to 6 were found to be more effective in suppressing wrinkles on the convex side of the curved portion 10 than in the comparative example.

No. 1 and no. 2, when the first bead 4a or the second bead 4b was formed, no noticeable wrinkles occurred on the concave side of the curved portion 10 by adopting pad foam molding.
Also, No. 3 to No. 6, when the first bead 4a or the second bead 4b is formed, it is possible to greatly suppress significant wrinkles on the concave side of the curved portion 10 in both foam molding and pad foam molding. .

At this time, No. 5 or No. 6, it was found that the same effect can be obtained even if the first bead 4a is arranged only in the wrinkle-prone portion.
Also, No. 5 and No. 6, it was found that providing the second beads 4b to the left and right first bent portions 1d, respectively, enhances the effect of suppressing wrinkles.
Also, No. 4, even when a half bead was adopted as the second bead 4b, a wrinkle reduction effect was obtained.

In addition, the amount of rotation due to molding was evaluated based on the movement of point A (the amount of movement before and after molding) with respect to wrinkle-generating danger area B, as shown in FIG.
The results are shown in FIG.
As can be seen from Figure 9, there is less material rotation in pad foam molding than in foam molding.
Moreover, it turned out that rotation of material can be suppressed by forming a bead in the top-plate part 1A or the 1st bending part 1d.

As described above, it was found that by forming the beads according to the present invention, the generation of wrinkles on the concave side of the curved portion 10 can be effectively suppressed.
Although described herein with reference to a limited number of embodiments, the scope of rights is not limited thereto, and modifications of each embodiment based on the above disclosure will be obvious to those skilled in the art.

1 Press part 1A Top plate part 1B Side wall part 1C Flange part 1D Ridge part 1E along the first bent part Ridge part 1d along the second bent part First bent part 1e Second bent part 2 Preforming step 3 Parts forming Step 4 Metal plate 4a First bead 4b Second bead 10 Curved portion

Claims (14)

a top plate portion and a cross section having a side wall portion continuous to at least one of the top plate portion in the width direction via a first bent portion and a flange portion continuous to the side wall portion via a second bent portion; And a press part for forming a metal plate into a press part shape having one or more curved portions that are concavely curved toward the side wall portion when viewed from above along the longitudinal direction, which is the direction that intersects the cross section. A manufacturing method comprising:
A first bead extending along the longitudinal direction is formed on the metal plate at a position to be the second bent portion, at least in a region to be the curved portion and toward the concave side wall portion side. In addition, a second portion extending along the longitudinal direction at a position corresponding to at least one of the top plate portion and the first bent portion with respect to a region serving as the curved portion forming at least the first bead. a preforming step comprising forming a bead;
a part forming step of forming the metal plate after the preforming step into the shape of the pressed part;
with
The metal body is a high-tensile steel plate having a tensile strength of 590 MPa or more,
The first bead and the second bead are provided only in the area to be the curved portion,
A method of manufacturing a pressed part, characterized by: 2. The method of manufacturing a press part according to claim 1, wherein the first bead has a shape that is concave in the same direction as the concave direction of the second bent portion. A region that includes a plate portion that is presumed to cause wrinkles in the flange portion when a metal plate made of a flat plate is press-molded into the shape of the press part on the side of the side wall portion that is the curved portion and is the concave portion. 3. The method of manufacturing a press part according to claim 1, wherein the first bead is partially formed. 4. The method of manufacturing a pressed part according to any one of claims 1 to 3, wherein the height of the first bead is at least one time the thickness of the metal plate. 5. The method of manufacturing a pressed part according to any one of claims 1 to 4, wherein the second bead is formed only at a position corresponding to the first bent portion. 6. The method of manufacturing a pressed part according to claim 5, wherein the second bead has a shape projecting in the same direction as the projecting direction of the first bent portion. a top plate portion and a cross section having a side wall portion continuous to at least one of the top plate portion in the width direction via a first bent portion and a flange portion continuous to the side wall portion via a second bent portion; And a press part for forming a metal plate into a press part shape having one or more curved portions that are concavely curved toward the side wall portion when viewed from above along the longitudinal direction, which is the direction that intersects the cross section. A manufacturing method comprising:
a first bead that extends along the longitudinal direction at a position that becomes the second bent portion on the side of the side wall portion that becomes the recess in at least a region that becomes the curved portion in the metal plate; and forming at least one bead selected from two kinds of beads, ie, a second bead extending along the longitudinal direction at a position corresponding to at least one of the top plate portion and the first bent portion. a preforming step;
A part forming step of forming the metal plate after the preforming step into the shape of the pressed part while restraining the position of the top plate portion with a pad;
with
The metal body is a high-tensile steel plate having a tensile strength of 590 MPa or more,
At least one bead selected from the first bead and the second bead is provided only in the area to be the curved portion,
A method of manufacturing a pressed part, characterized by: a top plate portion and a cross section having a side wall portion continuous to at least one of the top plate portion in the width direction via a first bent portion and a flange portion continuous to the side wall portion via a second bent portion; and a metal plate for press forming into a press part shape having one or more curved portions that are concavely curved toward the side wall portion when viewed from above along the longitudinal direction, which is the direction that intersects the cross section. There is
a first bead extending along the longitudinal direction at a position serving as the second bending portion at least in a region serving as the curved portion and with respect to the concave side wall portion side;
a second bead extending along the longitudinal direction at a position corresponding to at least one of the top plate portion and the first bent portion with respect to a region serving as the curved portion forming at least the first bead;
has
The metal body is a high-tensile steel plate having a tensile strength of 590 MPa or more,
The first bead and the second bead are provided only in the area that becomes the curved portion,
A metal plate characterized by: 9. The metal plate according to claim 8, wherein the first bead is concave in the same direction as the concave direction of the second bent portion. A region that includes a plate portion that is presumed to cause wrinkles in the flange portion when a metal plate made of a flat plate is press-molded into the shape of the press part on the side of the side wall portion that is the curved portion and is the concave portion. 10. The metal plate according to claim 8 or 9, wherein the first bead is partially formed on the metal plate. 11. The metal plate according to any one of claims 8 to 10, wherein the bead height of the first bead is at least 1 time the plate thickness of the metal plate. 12. The metal plate according to any one of claims 8 to 11, wherein the second bead is formed only at a position that becomes the first bent portion. 13. The metal plate according to claim 12, wherein the second bead is concave in the same direction as the concave direction of the first bent portion. a top plate portion and a cross section having a side wall portion continuous to at least one of the top plate portion in the width direction via a first bent portion and a flange portion continuous to the side wall portion via a second bent portion; The top plate is restrained by a pad in a press part shape having one or more concave curved portions toward the side wall portion when viewed from above along the longitudinal direction, which is the direction intersecting the cross section. A metal plate for press molding with
a first bead extending along the longitudinal direction at a position serving as the second bending portion with respect to the side wall portion which is at least the area serving as the curved portion and which is the recess, and the top plate portion; and a second bead extending along the longitudinal direction at a position corresponding to at least one of the first bent portions, at least one bead selected from two kinds of beads is formed ,
The metal body is a high tensile plate having a tensile strength of 590 MPa or more,
At least one bead selected from the first bead and the second bead is provided only in the area that becomes the curved portion,
A metal plate characterized by

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