JP7283439B2 - 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 technique for manufacturing a pressed part having a shape of a pressed part having one or more curved portions that are curved so as to be convex on the top view side and side wall portion side (width direction).
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 inferior in ductility and Lankford value is used as the metal plate, the above-mentioned 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 molding is performed by pad foam molding, draw molding, and their combined processes.
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 convexly curved toward the side wall portion side (width direction) in a top view along the longitudinal direction. It is an object of the present invention to suppress the occurrence of wrinkles on the convex side of a curved portion by a simple means during press molding into a shape.

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 width direction of the top plate portion via a first bent portion, and a side wall portion connected to the side wall portion via a second bent portion. It has a cross section having a flange portion that is continuous with the cross section, and has one or more curved portions that are curved so as to be convex toward the side wall portion when viewed from above along the longitudinal direction that is the direction that intersects the cross section. A method of manufacturing a pressed part for forming a metal plate into a shape of a pressed part, wherein the second bent portion is formed on the metal plate at least in a region to be the curved portion toward the convex side wall portion side. A preforming step having a step of forming a first bead extending along the longitudinal direction at a position where the The gist is to provide

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 that are curved so as to be convex 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 to 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 side wall portion that becomes the convex. The gist is that an existing first bead is formed.

According to the aspect of the present invention, before press-molding a metal plate into a press part shape having a curved portion that curves toward the side wall side in a top view, at least the region that will become the curved portion and the convex side wall portion side On the other hand, a bead is formed at a bent portion (ridgeline portion) connecting the side wall portion and the flange portion. As a result, according to the aspect of the present invention, the shape rigidity of the metal plate at the position on the convex side of the curved portion is improved. As a result, in the embodiment of the present invention, the surfaces of the side walls and the flange on the convex side of the curved portion are prevented from buckling due to being unable to withstand the compressive force during press forming. It is possible to efficiently suppress the occurrence of wrinkles in the flange portion without necessarily restraining the flange portion with a mold and performing 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. FIG. 4 is a perspective view explaining a first bead formed in a preforming step; It is a schematic diagram seen from the front showing an example of a bead after a preforming process. It is a schematic diagram seen from the front showing a second example of beads after the preforming process. It is a figure explaining the molding example in a component molding process. FIG. 10 is a schematic plan view from the viewpoint of information explaining the reason why wrinkles are generated on the convex side of the curved portion; It is a figure which shows the example of wrinkle generation.

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 object of the present embodiment, includes at least a top plate portion and a side wall portion continuous to at least one of the left and right sides of the top plate portion via a first bent portion, and a second bent portion on the side wall 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 upper side wall portion 1B is the convex side wall portion in the left curved portion, and the lower side wall portion 1B is the convex 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 in which the metal plate 4 is preliminarily formed 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, a flat metal plate 4 is formed at least in a region that will become the curved portion 10, toward the convex side wall portion 1B side, and the second bent portion 1e (see FIG. 3). 4), the first bead 4a extending along the longitudinal direction is formed in a press molding process.

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. An example of the first bead 4a is shown in FIG. This example is an example in which the first bead 4a is composed of a full bead.
Here, the first bead 4a of the present embodiment has a shape extending in the longitudinal direction (longitudinal direction of the top plate portion 1A), which is the direction in which the cross section of the bent shape intersects the cross section. The first bead 4a is a full bead, a half bead having a stepped cross-section, or the like. The same applies to the second bead 4b, which will be described later.

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.
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 position of the second bent portion 1e, the first bead 4a is formed. A bead shape that imitates is formed. The position at which the first bead 4a is formed is a position in the part molding process 3 where it can come into contact with the die shoulder ridge line of the mold in the part molding process 3 .
Then, in the preforming step 2, the metal plate 4 is press-formed using the upper mold and the lower mold described above to form the metal plate 4 having the first beads 4a extending along the longitudinal direction.

<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 on the convex side 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 bent in the same direction, the first bead 4a is formed only along the second bent portion 1e on one side wall portion 1B side of the curved portion 10, which is the convex side. Just do it. 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 where the curved portion 10 is to be formed and the curved portion is convex.
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 to be curved.

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 convex and which is the region that becomes the curved portion 10 . For example, it is presumed that wrinkles are generated in the flange portion 1C or the side wall portion 1B when the metal plate 4 made of a flat plate is press-molded into the shape of the press part on the side of the side wall portion 1B that is convex in the area that becomes the curved portion 10. The first bead 4a may be partially formed only in the region including the plate portion to be welded.
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.
Alternatively, for simplicity, the convex side of the curved portion 10 where the radius of curvature of the curved portion 10 is greater than or equal to a preset value may be the plate portion where wrinkles are estimated to occur.

<Second bead 4b>
The preforming step 2 may be a pressing step for forming the second bead 4b on the metal plate 4 together with the first bead 4a, as shown in FIG.
The second bead 4b is a bead that extends along the longitudinal direction at the position of the first bent portion 1d. Here, 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. This ridgeline portion 1D is curved so as to be convex upward.

In this case, as the mold used in the preforming step 2, the molding surfaces 20 and 21 of the upper mold (die) and lower mold (punch) are provided along the positions of the first bent portion 1d and the second bent portion 1e. That is, a bead shape that follows the second bead 4b and a bead shape that follows the first bead 4a extending in the longitudinal direction are formed. 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.

Here, 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 convex side wall portion 1B in the region 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.
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, the metal plate 4 after the preforming step 2 is press-molded using upper and lower molds having forming surfaces 20 and 21 as shown in FIG. is press part 1.
FIG. 6 illustrates a case of adopting pad foam molding having a pad 22 that presses 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 employed.

(Other operations)
In the present embodiment, in the preforming step 2, as preforming, the metal plate 4 is provided with at least the first bead 4a out of the first bead 4a and the second bead 4b (Fig. 3).
In the metal plate 4 in the preforming step 2, the shape rigidity in the longitudinal direction is increased in the beaded portion and in the vicinity of the beaded portion along the longitudinal direction due to the addition of the bead.
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 convex side wall portion 1B and the flange portion 1C of the curved portion 10 is high, so that the occurrence of wrinkles due to buckling on the convex side of the curved portion 10 is suppressed.

The operation and the like of this embodiment will be further described in detail.
When focusing on the portion of the metal plate 4 that becomes the side wall portion 1B and the flange portion 1C on the convex side of the curved portion 10, the line length of the flange edge on the convex side of the curved portion 10, as shown in FIG. In the case of press molding in the molding step 3, the line length changes in the direction of shortening, like L1→L2 in FIG. As described above, the longitudinal line lengths of the convex side wall portion 1B and the flange portion 1C of the curved portion 10 are shortened by the press forming in the component forming step 3, so that the convex side flange portion 1C has a longitudinal line length. directional compressive force is generated.
As a result, conventionally, the side wall portion 1B and the flange portion 1C on the convex side of the curved portion 10 cannot withstand the compressive force during press molding, and the flange portion 1C and the surface near the connection portion between the flange portion 1C and the side wall portion 1B are Buckling causes wrinkles (see FIG. 8).

On the other hand, in the present embodiment, the metal plate 4 press-formed in the component forming step 3 is bent at the first bent portion 1d, which is the connection portion between the side wall portion 1B and the flange portion 1C, on the convex side of the curved portion 10. After providing at least the first bead 4a along the position of the formed ridgeline 1D (along the longitudinal direction), press molding in the component molding step 3 is performed. For this reason, in the present embodiment, the metal plate 4 to be formed has a high longitudinal shape rigidity in the regions that become the side wall portion 1B and the flange portion 1C located on the convex side of the curved portion 10, and the desired pressed part shape is obtained. As a result of press molding, buckling during molding is suppressed, and wrinkles at the side wall portion 1B and the flange portion 1C on the convex side of the curved portion 10 are 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.
As a result, the occurrence of wrinkles in the side wall portion 1B and the flange portion 1C on the convex side of the curved portion 10 is suppressed without deteriorating the yield and without changing the intended shape of the pressed 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 .

Moreover, when it is desired to further suppress the occurrence of wrinkles, it is preferable to provide a second bead 4b as shown in FIG. In this case, the shape rigidity in the longitudinal direction is further increased in the regions forming the side wall portion 1B and the flange portion 1C located on the convex side of the curved portion 10, and the side wall portion 1B and the flange portion 1C located on the convex side of the curved portion 10 Wrinkles are less likely to occur.
It should be noted that the second bead is also erased by overlapping with the ridge line in the press molding in the component molding process 3 . The second bead may be left as part of the shape of the part if the shape of the part permits.
In this case as well, it is preferable to limit the second bead 4b within the area of the curved portion 10 when shape accuracy is taken into consideration.

(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 is curved so as to be convex toward the side wall portion 1B when viewed from the top along a longitudinal direction which is a direction intersecting the cross section. Alternatively, 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 is formed on the metal plate 4 at least in a region that becomes the curved portion 10 and is the convex. a preforming step 2 having a step of forming a first bead 4a extending along the longitudinal direction at a position to be the second bent portion 1e with respect to the side, and the metal plate after the preforming step 2 4 is formed into the shape of the press part.

According to this configuration, the shape rigidity of the metal plate 4 at the position on the convex side of the curved portion 10 is improved. As a result, in the present embodiment, the surfaces of the side wall portion 1B and the flange portion 1C on the convex side of the curved portion 10 are prevented from being unable to withstand the compressive force during press molding and buckling. It is possible to efficiently suppress the generation of wrinkles in the side wall portion 1B and the flange portion 1C in the above without necessarily restraining the flange portion 1C with a mold and performing press molding.

(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) 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 which 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. It is preferable to partially form the first bead 4a in a region including a plate portion that is presumed to be wrinkled.
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) In the preforming step 2, at least a first bent portion 1d extending along the longitudinal direction in a region to be the curved portion 10 forming the first bead 4a is formed. A process for forming two beads 4b may be performed.
According to this configuration, as a result of forming the second bead 4b together with the first bead 4a, the shape rigidity along the longitudinal direction on the convex side of the curved portion 10 can be set even higher. As a result, wrinkles are less likely to occur with this configuration.

(6) It is preferable that the second bead has a shape convex in the same direction as the convex direction of the first bent portion.
According to this configuration, the second bead 4b is superimposed on the ridgeline portion 1D formed by the first bent portion 1d and erased when forming the desired pressed part shape while further increasing the shape rigidity of the convex side of the curved portion. becomes easier.

(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 side wall portion 1B are provided with the second bent portion 1e. 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 is curved so as to be convex toward the side wall portion 1B when viewed from the top 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, at least in the area that becomes the curved portion 10, the side wall portion 1B side that becomes the convex, the above-mentioned second 2 A metal plate 4 is used in which a first bead 4a extending along the longitudinal direction is formed at a position to be the bent portion 1e.

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 the section, and is curved so as to be convex toward the side wall portion 1B in a top view 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 convex 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 convex 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 the comparative example, the metal plate 4 used was a flat plate material in which beads were not formed.
In addition, in the example of the present invention, 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 of the present invention example. 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.
Example No. of the present invention. 2 is an example in which the first bead 4a (full bead) is formed only on the portions located on the respective convex sides of the two curved portions 10. FIG. Note that the second bead 4b is not formed.

Example No. of the present invention. 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.
Example No. of the present invention. 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.

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 convex side of the curved portion 10 of the molded product, and evaluating the results in three stages of ⊚, ∘, and Δ.
Specifically, "×" indicates that significant wrinkles occurred, "◯" indicates that there were slight wrinkles although no significant wrinkles occurred, and "◎" indicates that no wrinkles occurred at all.

As can be seen from Table 2, in the comparative example, in the target pressed part shape, when the tensile strength of the metal plate 4 is 590 MPa or more, in any metal plate 4, when no bead is provided, the flange portion 1C has noticeable wrinkles. There has occurred.
On the other hand, No. of the present invention example. It was found that all of Nos. 1 to 4 were able to significantly reduce wrinkles.
At this time, No. 1 and No. 2, 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. 1 and No. 3, it was found that providing the second bead 4b together with the first bead 4a further enhances the effect of suppressing wrinkles.
Also, No. 4, when a half bead is adopted as the second bead 4b, no. Although it is equivalent to the evaluation of No. 1, according to visual observation, it is slightly inferior to No. 1. 4 was more effective in reducing wrinkles.

As described above, it was found that the formation of the bead according to the present invention effectively suppresses the occurrence of wrinkles on the convex side of the curved portion 10 .
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 (12)

a top plate portion and a cross section having a side wall portion continuous to at least one of the width direction of the top plate portion 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 curved so as to be convex 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 the region to be the curved portion and toward the side wall portion which is the convex portion. a preforming step comprising the step of
a part forming step of forming the metal plate after the preforming step into the shape of the pressed part;
with
The metal plate is a high-tensile steel plate having a tensile strength of 590 MPa or more,
The first bead is provided only on the side of the side wall portion that becomes the protrusion and only in the area that becomes 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 plate that is presumed to cause wrinkles in the flange portion or the side wall 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 region that becomes the curved portion and is the convex side. 3. The method of manufacturing a pressed part according to claim 1, wherein the first bead is partially formed in a region including the portion. 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. The preforming step includes forming a second bead extending along the longitudinal direction at a position to be the first bent portion in at least a region to be the curved portion forming the first bead. A method of manufacturing a pressed part according to any one of claims 1 to 4, characterized by: 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 width direction of the top plate portion 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 curved so as to be convex 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 is formed at a position to be the second bent portion at least on the side of the side wall portion which is the region to be the curved portion and which is the convex , and
The metal plate is a high-tensile steel plate having a tensile strength of 590 MPa or more,
The first bead is provided only on the side of the side wall portion that becomes the protrusion and only in the area that becomes the curved portion.
A metal plate characterized by: 8. The metal plate according to claim 7, wherein the first bead is concave in the same direction as the concave direction of the second bent portion. A plate that is presumed to cause wrinkles in the flange portion or the side wall 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 region that becomes the curved portion and is the convex side. 9. The metal plate according to claim 7 or 8, wherein the first bead is partially formed in a region including the portion. 10. The metal plate according to any one of claims 7 to 9, wherein the bead height of the first bead is at least 1 time the plate thickness of the metal plate. A second bead extending along the longitudinal direction is formed at a position to be the first bent portion with respect to a region to be the curved portion forming at least the first bead. The metal plate according to any one of claims 7 to 10. 12. The metal plate according to claim 11, wherein the second bead has a shape projecting in the same direction as the projecting direction of the first bent portion.

Images