JP2021176646A - Manufacturing method for press component, metal plate for press molding, and high-tensile steel plate - Google Patents

Abstract

To suppress occurrence of wrinkles on a projecting side of a curved part by simple means when press-molding along a longitudinal direction the material into a press component shape having a curved part along the longitudinal direction in a top view.MEANS FOR SOLVING THE PROBLEM: A manufacturing method for a press component 1 for forming a metal plate 4 into a press component shape that has a cross-section having a top plate part 1A, side-wall parts 1B and flange parts 1C and also has one or two or more curved parts 10 curved so as to project toward the side-wall part 1B side in a top view, along a longitudinal direction being a direction crossing the cross-section, includes: a preliminary forming step 2 having a step of forming on the metal plate 4, first beads 4a extending along the longitudinal direction in respective positions to become second bent parts 1e, relative to the projecting side-wall part 1B side, which respective positions are in areas to become at least the curved part(s) 10; and a component forming step 3 of forming the metal plate 4 after the preliminary molding step 2 into the press component shape.SELECTED DRAWING: Figure 2

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 and a side wall portion and a flange portion continuous with the top plate portion, and in the longitudinal direction which is a direction intersecting the cross section. Along the same, the present invention relates to a technique for manufacturing a pressed part that manufactures a pressed part in the shape of a pressed part having one or two curved portions curved so as to be convex on the upper surface view side and the side wall portion side (width direction).
Here, in the present specification, the top view refers to the case where the top plate portion and the like are viewed from the plate thickness direction of the top plate portion.

Many stamped parts, including automobiles and home appliances, are made by transforming a flat metal plate into various shapes. When mass-producing pressed parts, press forming (pressing) in which a metal plate is deformed using a press machine and a die is widely used. Normally, the metal plate before processing is flat, and in order to deform it into a complicated three-dimensional shape, the metal plate must expand and contract according to the three-dimensional shape. However, as the shape of the pressed part becomes more complicated, it becomes difficult to give the metal plate expansion and contraction according to the three-dimensional shape. In particular, when a difficult-to-mold 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 Rankford value is used for the metal plate, the above difficulties are likely to occur.

If the metal plate is not stretched or contracted according to the three-dimensional shape, molding defects such as cracks and wrinkles occur in the metal plate. That is, when the metal plate is deformed into a three-dimensional shape, the metal plate has to stretch in a part where the length of the metal plate is insufficient to make up for the shortage from the surroundings, and the metal plate pulls beyond its own ductility. If it is done, cracks will occur. On the other hand, wrinkles tend to occur when the length of the metal plate must be shortened when it is deformed into a three-dimensional shape, or when it excessively flows in from the surroundings.

As an example of a part shape that is difficult to press-mold, it has a cross section including a top plate portion, a side wall portion continuous with the top plate portion, and a flange portion continuously formed on the side wall portion, and in the longitudinal direction. Along the top view, there are press-molded parts having one or more curved shapes in the width direction.
When such a complicated part shape is press-molded from a flat metal plate, tensile deformation and compression deformation occur during molding, so that the press part is liable to crack or wrinkle.

Here, when a product having a complicated shape as described above is press-molded from a metal plate, for example, bending using a die consisting of a punch, a die, and a pad, punching, a die, and a blank holder (wrinkles) are performed. Drawing is performed using a mold consisting of a presser). In the case of bending, wrinkles are generated in the flange portion, which causes molding defects. In the case of drawing, wrinkles are generated on the top plate, which causes molding defects.
As a countermeasure for this problem, for example, there is a method for manufacturing a curved part and a device for manufacturing a curved part described in Patent Document 1.

Japanese Patent No. 5733475

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

Further, regarding foam molding, the mold structure is simple and low cost, but since neither the top plate portion nor the flange portion is restrained, wrinkles are likely to occur on the top plate surface in addition to the flange portion. Therefore, conventionally, foam molding is not mainly performed, but is molded by pad foam molding, draw molding, and a combined process thereof.
Here, in the method described in Patent Document 1, since the top plate portion is restrained by the pad and the flange portion is also restrained by the blank holder, tension and compressive deformation of both the top plate portion and the flange portion can be suppressed. You can. However, in addition to the normal drawing process, it is necessary to restrain the material with a pad, resulting in inferior productivity. The cost of the mold is also high.

The present invention has been made by paying attention to the above points, and is a pressed component having one or more curved portions that are convexly curved toward the side wall portion side (width direction) in the top view along the longitudinal direction. The purpose is to suppress the occurrence of wrinkles on the convex side of the curved portion by a simple means during press molding into a shape.

In order to solve the problem, in one aspect of the present invention, a side wall portion continuous with at least one of the top plate portion and the top plate portion in the width direction via the first bending portion and the side wall portion via the second bending portion. It has a cross section having a continuous flange portion, and has one or two or more curved portions curved so as to be convex toward the side wall portion in a top view along the longitudinal direction which is a direction intersecting the cross section. A method for manufacturing a pressed part in which a metal plate is formed into a pressed part shape. The second bent portion is formed on the metal plate with respect to at least the curved portion and 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 to be The gist is to prepare.

Further, in another aspect of the present invention, a side wall portion continuous with at least one of the top plate portion and the top plate portion in the width direction via the first bent portion and the side wall portion continuous with the side wall portion via the second bent portion. A pressed part shape having a cross section having a flange portion and having one or two curved portions curved so as to be convex toward the side wall portion in a top view along the longitudinal direction which is a direction intersecting the cross section. In addition, it is a metal plate for press molding, and extends along the longitudinal direction to a position to be the second bent portion with respect to the side wall portion side which is at least the region to be the curved portion and is convex. The gist is that the existing first bead is formed.

According to the aspect of the present invention, before the metal plate is press-molded into the shape of a pressed part having a curved portion curved toward the side wall portion in a top view, at least the region to be the curved portion and the convex side wall portion side. On the other hand, a bead is formed at a position that serves as a bending portion (ridgeline portion) that connects the side wall portion and the flange portion. As a result, according to the aspect of the present invention, the shape rigidity of the position on the convex side of the curved portion of the metal plate is improved. As a result, in the embodiment of the present invention, the side wall portion on the convex side of the curved portion and the surface of the flange portion are prevented from buckling because they cannot withstand the compressive force during press molding, and the side wall portion on the convex side of the curved portion and the side wall portion and the flange portion are prevented from buckling. The occurrence of wrinkles on the flange portion can be efficiently suppressed without necessarily restraining the flange portion with a mold and press forming.

It is a figure which shows the shape of the pressed part which concerns on embodiment based on this invention, (a) is a perspective view, (b) is a sectional view. It is a figure which shows the process example of the manufacturing method of the pressed part which concerns on embodiment based on this invention. It is a perspective view explaining the 1st bead formed in the preforming process. It is a schematic view seen from the front which shows the bead example after a premolding process. It is a schematic view seen from the front which shows the example of the 2nd bead after the preforming process. It is a figure explaining the molding example in a part molding process. It is a schematic plan view seen from the information explaining the reason why wrinkles occur on the convex side of a curved portion. It is a figure which shows the example of the occurrence of wrinkles.

Next, an embodiment of the present invention will be described with reference to the drawings.
(Pressed part shape)
The shape of the pressed part after press molding, which is the target of the present embodiment, has a side wall portion which is continuous with at least one of the top plate portion and both sides in the left-right width direction via the first bending portion and a second bending 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 through the cross section. Further, the above-mentioned pressed part shape has one or more curved portions curved in the width direction along the longitudinal direction in a top view at one or more locations in the longitudinal direction, which is a direction intersecting the cross section. The shape. The curved portion may be determined based on whether or not the top plate portion is curved in the width direction.
Here, the present embodiment is a technique suitable for manufacturing a pressed part using a metal plate made of a difficult-to-mold member having inferior ductility and Rankford value, such as a high-strength steel plate having a tensile strength of 590 MPa or more and an aluminum alloy plate. be.

In the present embodiment, as the shape of the press part 1 of the target press part 1 after press molding, a press having a hat-shaped cross section as shown in FIG. 1 and having curved portions 10 at two positions along the top view and the longitudinal direction. The case of molding into a part shape will be described as an example. That is, in the present embodiment, as shown in FIG. 1, as the target pressed part shape, the top plate portion 1A is curved in the width direction at two locations along the longitudinal direction, that is, in the top view, with a hat-shaped cross section. The case where there is a curved portion 10 is illustrated. In the example of FIG. 1A, in the curved portion on the left side, the upper side wall portion 1B is the convex side wall portion, and in the curved portion on the right side, the lower side wall portion 1B is the convex side wall portion.

However, in the present embodiment, the curved portion 10 may be at one location, or the curved portion 10 may be at three or more locations. Further, the number of curved portions 10 may be two or more, or the curved portions 10 at two adjacent portions may both be curved in the same direction.
It should be noted that the dimensions shown in FIG. 1B are the dimensions in the examples and do not limit the present invention in any way.

(composition)
As shown in FIG. 2, the method for manufacturing the pressed part 1 of the present embodiment includes a preforming step 2 and a part forming step 3.

<Preliminary molding process 2>
The preforming step 2 is a step of applying a preliminary molding before the main molding to the metal plate 4 to obtain a metal plate for the main molding, which is less likely to cause wrinkles.
In the preforming step 2, as shown in FIG. 3, the second bent portion 1e (FIG. 3) is formed on the flat metal plate 4 with respect to the side wall portion 1B side which is at least the region to be the curved portion 10 and is convex. It has a press molding process step of forming a first bead 4a extending along the longitudinal direction at a position (see 4).

In the preforming step 2 of the present embodiment, as shown in FIG. 3, the first bead extends along the longitudinal direction over the entire position of the left and right second bent portions 1e with respect to the flat metal plate 4. It has a step of forming 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 composed of a full bead, a half bead having a stepped cross section, or the like. The same applies to the second bead 4b described later.

The second bent portion 1e corresponds to the cross section of the ridge line portion 1E formed between the side wall portion 1B and the flange portion 1C. The ridge line portion 1E is bent so as to be concave on the upper side.
The molding surfaces of the upper mold (die) and the lower mold (punch) forming the mold used in the preforming step 2 are formed on the first beads 4a along the positions of the second bending portions 1e, respectively. A bead shape that imitates is formed. The position where the first bead 4a is formed is a position in the part molding step 3 where the die shoulder ridge of the mold in the part molding step 3 can be brought into contact with the die shoulder ridge.
Then, in the preforming step 2, the metal plate 4 is press-molded using the above upper and lower dies to obtain the metal plate 4 provided with the first bead 4a extending in the longitudinal direction.

<About the formation of the 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 of the mold in the part molding step 3.
The first bead 4a preferably has a shape that is concave in the same direction as the concave direction of the second bent portion 1e (a shape that is convex downward) (see FIG. 4).
The bead height of the first bead 4a is preferably one or more times the plate thickness of the metal plate 4. It is preferably twice or more. The upper limit of the height of the first bead 4a is 30 mm.

In the present embodiment, the two curved portions 10 are provided, and the curved directions of the two curved portions 10 are different from each other. That is, since both the side wall portions 1B on the left and right sides are on the convex side of the curved portion 10, the first beads 4a are individually formed along the second bent portions 1e on the left and right sides.
When all the bending directions of the bending portions 10 are the same, the first bead 4a is formed only along the second bending portion 1e on the one side wall portion 1B side which is the convex side of the bending portion 10. Just do it. However, even in this case, the first bead 4a may be formed on the opposite side as well.
Further, 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 ridge line portion 1E formed between the side wall portion 1B and the flange portion 1C. Illustrated.

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

At this time, it is not necessary to form the first bead 4a in all of the ridge line portions 1E located on the side wall portion 1B side where the curvature is convex in the region to be the curved portion 10. For example, it is estimated that wrinkles occur in the flange portion 1C or the side wall portion 1B when the metal plate 4 made of a flat plate is press-formed into the shape of the pressed part on the side wall portion 1B that is convex in the region to be the curved portion 10. The first bead 4a may be partially formed only in the region including the plate portion to be formed.
The process of determining the plate portion where wrinkles are presumed to occur may be executed by molding analysis using a computer, or may actually be press-molded.
Further, simply, the convex side of the curved portion 10 in which the radius of curvature of the curved portion 10 is equal to or larger than a preset value may be used as a plate portion where wrinkles are estimated to occur.

<Second bead 4b>
As shown in FIG. 5, the preforming step 2 may be a pressing step of forming the second bead 4b on the metal plate 4 together with the first bead 4a.
The second bead 4b is a bead extending 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 ridge line portion 1D formed between the top plate portion 1A and the side wall portion 1B. The ridge line portion 1D is bent so as to be convex upward.

In this case, as the dies used in the preforming step 2, the molding surfaces 20 and 21 of the upper die and the lower die are along the positions of the first bending portion 1d and the second bending portion 1e. That is, a bead shape following the second bead 4b extending along the longitudinal direction and a bead shape following the first bead 4a are formed. The position where the first bead 4a and the second bead 4b are formed is a position in the part molding step 3 where the punch shoulder ridge portion and the die shoulder ridge portion of the mold in the part molding step 3 can be brought into contact with each other.

Here, it is not necessary to form the second bead 4b over the entire position of the ridge line 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 serving as the first bending portion 1d with respect to a region serving as a 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. The second bead 4b is a region to be the curved portion 10, and is preferably provided on the first bent portion 1d side on the convex side wall portion 1B side.

Further, the second bead 4b preferably has a shape that is convex in the same direction as the convex direction of the first bent portion 1d (a shape that is convex upward in the cross section).
Further, the bead height of the second bead 4b is preferably 1 times or more the plate thickness of the metal plate 4. 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.

<Part molding process 3>
The part molding step 3 is a main molding step of molding the metal plate 4 processed in the preforming step 2 into a target pressed part shape.
In the part forming step 3, the metal plate 4 after the treatment of the preforming step 2 is press-molded using the upper and lower dies having the forming surfaces 20 and 21 as shown in FIG. Let's call it the pressed part 1.
FIG. 6 illustrates a case where pad foam molding having a pad 22 for pressing the top plate portion 1A is adopted. That is, in this example, the case of bending molding is illustrated. In the part molding step 3, foam molding in which the top plate portion 1A is not pressed by the pad 22 may be adopted.

(Operation and others)
In the present embodiment, in the preforming step 2, as preforming, a process of imparting at least the first bead 4a of the first bead 4a and the second bead 4b to the metal plate 4 is executed (FIG. 6). 3).
In the metal plate 4 of the preforming step 2, the shape rigidity in the longitudinal direction of the portion where the bead is formed and in the vicinity thereof is increased by applying the bead along the longitudinal direction.
Next, when the metal plate 4 after the pre-molding step 2 is pressed in the part molding step 3 to form a hat-shaped cross section having a curved portion 10 curved in the width direction (left-right direction) in the top view, the bead is formed. As a result, the shape rigidity of the convex side wall portion 1B and the flange portion 1C in the curved portion 10 in the longitudinal direction 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 described in more detail.
When focusing on the portion of the metal plate 4 that becomes the convex side wall portion 1B and the flange portion 1C of the curved portion 10, the line length of the flange end edge on the convex side of the curved portion 10 is a component as shown in FIG. When press molding is performed in the molding step 3, the line length changes in the direction of shortening as shown in L1 → L2 in FIG. As described above, the line lengths of the convex side wall portion 1B and the flange portion 1C of the curved portion 10 in the longitudinal direction are shortened by the press molding in the part molding step 3, so that the linear length is longer than that of the convex side flange portion 1C. A directional compressive force is generated.
As a result, conventionally, in the side wall portion 1B and the flange portion 1C on the convex side of the curved portion 10, the surface near the connection portion between the flange portion 1C and the flange portion 1C and the side wall portion 1B cannot withstand the compressive force during press molding. Bending causes wrinkles (see FIG. 8).

On the other hand, in the present embodiment, with respect to the metal plate 4 press-molded in the part molding step 3, the first bent portion 1d, which is the connecting portion between the side wall portion 1B and the flange portion 1C, on the convex side of the curved portion 10. After applying at least the first bead 4a along the position of the formed ridge line 1D (along the longitudinal direction), the press molding in the part molding step 3 is performed. Therefore, in the present embodiment, the metal plate 4 to be molded has a desired press component shape in a region where the side wall portion 1B and the flange portion 1C located on the convex side of the curved portion 10 have high shape rigidity in the longitudinal direction. As a result of press molding, buckling during molding is suppressed, and wrinkles on 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 pre-molding step 2 is press-molded in the part molding step 3, and is erased by overlapping with the ridge line 1E.
As a result, the generation of wrinkles on the convex side wall portion 1B and the flange portion 1C of the curved portion 10 is suppressed without deteriorating the yield and changing the shape of the target pressed part.
Here, when the metal plate 4 is a high-strength steel plate or the curved portion 10 has a component shape with a large curvature and the compressive force generated during molding is large, the shape accuracy of the pressed component shape is improved. If this is desired, it is preferable to reduce the range in which the first bead 4a is provided as much as possible. In this case, for example, it may be provided in the region of the curved portion 10.

Further, when it is desired to further suppress the occurrence of wrinkles, it is advisable to provide a second bead 4b as shown in FIG. In this case, the shape rigidity in the longitudinal direction in the region to be the side wall portion 1B and the flange portion 1C located on the convex side of the curved portion 10 is further increased, 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.
The second bead is also press-molded in the part molding step 3, and is erased by overlapping with the ridge line. If the part shape is acceptable, the second bead may be left as a part of the part shape.
Also in this case, when the shape accuracy is taken into consideration, it is preferable to limit the second bead 4b within the region of the curved portion 10.

(effect)
This embodiment has the following effects.
(1) In the present embodiment, a second bent portion 1e is provided on the side wall portion 1B and the side wall portion 1B which are continuous with the first bent portion 1d on at least one of the top plate portion 1A and the top plate portion 1A in the width direction. A curved portion 10 having a cross section having a continuous flange portion 1C via the cross section and being curved so as to be convex toward the side wall portion 1B in a top view along the longitudinal direction which is a direction intersecting the cross section is 1 Alternatively, it is a method of manufacturing a pressed part 1 in which a metal plate 4 is formed into a pressed part shape having two or more, and the side wall portion 1B which is at least a region to be a curved portion 10 and is convex on the metal plate 4. 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. A part molding step 3 for molding 4 into the shape of the pressed part is provided.

According to this configuration, the shape rigidity of the position of the curved portion 10 on the convex side of the metal plate 4 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 buckling because they cannot withstand the compressive force during press molding, and the convex side of the curved portion 10 is prevented. Wrinkles on the side wall portion 1B and the flange portion 1C in the above can be efficiently suppressed without necessarily restraining the flange portion 1C with a mold and press forming.

(2) The first bead 4a preferably has a shape that is concave in the same direction as the concave direction of the second bent portion 1e.
According to this configuration, when the first bead 4a is provided to increase the shape rigidity and the shape is formed into the desired pressed part shape, the first bead 4a is overlapped with the ridge line portion 1E composed of the second bent portion 1e. It becomes easy to erase.

(3) 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 pressed part on the side wall portion 1B side that is the region to be the curved portion 10 and is convex. It is preferable to partially form the first bead 4a in the region including the plate portion where wrinkles are presumed to occur.
According to this configuration, it is possible to reduce the region forming the first bead 4a.

(4) The bead height of the first bead 4a is preferably 1 times or more the plate thickness of the metal plate 4.
According to this configuration, wrinkle generation can be suppressed more reliably.

(5) The preforming step 2 extends along the longitudinal direction to a position of the first bent portion 1d with respect to a region of the curved portion 10 forming at least the first bead 4a. The process of forming the bead 4b of 2 may be executed.
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 to be higher. This makes wrinkles less likely to occur according to this configuration.

(6) The second bead preferably has a shape that is convex in the same direction as the convex direction of the first bent portion.
According to this configuration, the second bead 4b is overlapped with the ridge line portion 1D composed of the first bending portion 1d and erased when molding into the desired pressed part shape while further increasing the shape rigidity of the convex side of the curved portion. It will be easier.

(7) In the present embodiment, a second bent portion 1e is provided on the side wall portion 1B and the side wall portion 1B which are continuous with the first bent portion 1d on at least one of the top plate portion 1A and the top plate portion 1A in the width direction. A curved portion 10 having a cross section having a continuous flange portion 1C via the cross section and being curved so as to be convex toward the side wall portion 1B in a top view along the longitudinal direction which is a direction intersecting the cross section is 1 Alternatively, the metal plate 4 for press-molding the metal plate 4 into the shape of a pressed part having two or more, and at least the region to be the curved portion 10 and the convex side wall portion 1B side. 2 A metal plate 4 in which a first bead 4a extending along the longitudinal direction is formed at a position to be a bent portion 1e is used.

When this metal plate 4 is used, the side wall portion 1B which is continuous with the top plate portion 1A and at least one of the top plate portion 1A in the width direction via the first bending portion 1d and the second bending portion 1e on the side wall portion 1B. A curved portion 10 having a cross section having a flange portion 1C continuous through the cross section and curved so as to be convex toward the side wall portion 1B in a top view along the longitudinal direction which is a direction intersecting the cross section. When press-molding into the shape of a pressed part having one or more, wrinkles on the side wall portion 1B and the flange portion 1C on the convex side of the curved portion 10 are not necessarily press-molded by restraining the flange portion 1C with a die. However, it can be suppressed efficiently.

Here, it is preferable that the first bead 4a has a shape that is concave in the same direction as the concave direction of the second bent portion 1e.
Further, when the metal plate 4 made of a flat plate is press-molded into the shape of the pressed part on the side wall portion 1B that is the region to be the curved portion 10 and is convex, the flange portion 1C or the side wall portion 1B is formed. The first bead 4a may be partially formed in a region including a plate portion where wrinkles are presumed to occur.
Further, at least the region serving as the curved portion 10 forming the first bead 4a is formed with a second bead 4b extending along the longitudinal direction at a position serving as the first bent portion 1d. It may have a certain shape.

(8) The above-mentioned manufacturing method of the pressed part 1 can be applied even if 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 the press molding of the above embodiment based on the present invention will be described. The present invention is not restricted to the following examples.
"Applicable material"
As the metal plate 4, as shown in Table 1, four types of steel sheets, 590 MPa class steel sheet (590 material), 980 MPa class steel sheet (980 material), 1180 MPa class steel sheet (1180 material), and 1470 MPa class steel sheet (1470 material), are used. Using.
The dimensions of the metal plate 4 were a flat plate material having a width W = 240 mm and a length L = 387 mm.

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

In Table 2, in the comparative example, a flat plate material that does not form a bead on the metal plate 4 was used.
Further, in the example of the present invention, a flat plate material on which a bead based on the present invention was formed was used with respect to the metal plate 4 to be molded.
Specifically, No. 1 of the example of the present invention. Reference numeral 1 denotes an example in which a first bead 4a (full bead) is formed in the entire area along the left and right second bent portions 1e. The second bead 4b is not formed.
No. of the example of the present invention. Reference numeral 2 denotes an example in which the first bead 4a (full bead) is formed only in the portion of the two curved portions 10 located on each convex side. The second bead 4b is not formed.

No. of the example 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) is formed over the entire area along the left and right first bent portions 1d. This is an example of forming the bead 4b (full bead) of.
No. of the example 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. This is an example of forming the bead 4b (half bead) of.

In Table 2, "FORM" is a case where foam molding is adopted as press molding. “PADFORM” is a case where foam forming is performed with the top plate portion 1A position pressed by a pad as press forming.
In the wrinkle determination, the surface texture on the convex side of the curved portion 10 of the molded product was visually confirmed, and the evaluation was evaluated on a scale of ⊚, ◯, and Δ.
Specifically, the case where a remarkable wrinkle was generated was evaluated as "x", the case where no significant wrinkle was generated but a slight wrinkle was formed was evaluated as "○", and the case where no wrinkle was generated was evaluated as "◎".

As can be seen from Table 2, in the comparative example, when the tensile strength of the metal plate 4 is 590 MPa or more and the bead is not provided on any of the metal plates 4, the flange portion 1C has remarkable wrinkles. There has occurred.
On the other hand, No. It was found that in all of 1 to 4, remarkable reduction of wrinkles was achieved.
At this time, No. 1 and No. As can be seen from No. 2, it was found that the same effect can be obtained by arranging the first bead 4a only in the wrinkle-prone area.

In addition, No. 1 and No. As can be seen from No. 3, it was found that the effect of suppressing wrinkles was further enhanced by providing the second bead 4b together with the first bead 4a.
In addition, No. When a half bead is adopted as the second bead 4b as in No. 4, no. It is equivalent to the evaluation of No. 1, but visually, it is slightly No. 4 had a wrinkle reduction effect.

As described above, it has been found that by forming the bead based on the present invention, the occurrence of wrinkles on the convex side of the curved portion 10 can be effectively suppressed.
Although the description has been made 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 are obvious to those skilled in the art.

1 Pressed parts 1A Top plate part 1B Side wall part 1C Flange part 1D Ridge part along the first bending part 1E Ridge part along the second bending part 1d First bending part 1e Second bending part 2 Pre-molding process 3 Part molding Step 4 Metal plate 4a First bead 4b Second bead 10 Curved part

Claims (13)

It has a cross section having a side wall portion continuous via a first bent portion and a flange portion continuous with the side wall portion via a second bent portion on at least one of the top plate portion and the top plate portion in the width direction. A press component that forms a metal plate into a pressed component shape that has one or more curved portions that are curved so as to be convex toward the side wall portion in a top view along the longitudinal direction that intersects the cross section. It ’s a manufacturing method,
A first bead extending along the longitudinal direction is formed on the metal plate at a position that becomes the second bending portion with respect to the side wall portion that is at least the curved portion and is convex. A pre-molding process that has a process of
A part molding step of molding the metal plate into the shape of the pressed part after the preforming step, and
A method for manufacturing a pressed part, which comprises. The method for manufacturing a pressed 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 have wrinkles on the flange portion or the side wall portion when a metal plate made of a flat plate is press-formed into the shape of the pressed part on the side wall portion side surface that is the curved portion and is convex. The method for manufacturing a pressed part according to claim 1 or 2, wherein the first bead is partially formed in a region including a portion. The method for manufacturing a pressed part according to any one of claims 1 to 3, wherein the bead height of the first bead is at least one times the plate thickness of the metal plate. In the preforming step, at least the region to be the curved portion forming the first bead is formed with a second bead extending along the longitudinal direction at a position to be the first bent portion. The method for manufacturing a pressed part according to any one of claims 1 to 4. The method for manufacturing a pressed part according to claim 5, wherein the second bead has a shape that is convex in the same direction as the convex direction of the first bent portion. It has a cross section having a side wall portion continuous via a first bent portion and a flange portion continuous with the side wall portion via a second bent portion on at least one of the top plate portion and the top plate portion in the width direction. A metal plate for press molding into a pressed part shape having one or more curved portions curved so as to be convex toward the side wall portion in a top view along the longitudinal direction which is a direction intersecting the cross section. There,
It is determined that at least the first bead extending along the longitudinal direction is formed at the position of the second bent portion with respect to the side wall portion side which is the region to be the curved portion and is convex. Characterized metal plate. The metal plate according to claim 7, 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 have wrinkles on the flange portion or the side wall portion when a metal plate made of a flat plate is press-formed into the shape of the pressed part on the side wall portion side surface that is the curved portion and is convex. The metal plate according to claim 7 or 8, wherein the first bead is partially formed in a region including a portion. The metal plate according to any one of claims 7 to 9, wherein the bead height of the first bead is at least one times the plate thickness of the metal plate. It is characterized in that a second bead extending along the longitudinal direction is formed at a position of the first bending portion with respect to a region of the bending portion forming at least the first bead. The metal plate according to any one of claims 7 to 10. The metal plate according to claim 11, wherein the second bead has a shape that is convex in the same direction as the convex direction of the first bent portion. A high-strength steel plate having a tensile strength of 590 MPa or more for the method for manufacturing a pressed part according to any one of claims 1 to 6.

Images