KR102023541B1 - Method for manufacturing stretch-flange-formed component - Google Patents

Abstract

Elongated flange molded parts produced with elongated flange molding are produced with a low molding load while suppressing elongated flange breakage. The flange part 7 which has the 2nd concave outer peripheral part 7a by bending to the top plate part 3 side continuously in the top plate part 3 and the vertical wall part 5 which have the 1st concave outer peripheral part 3a. It is a manufacturing method for manufacturing an elongated flange molded part having a. An ridge 9 extending along the second concave outer circumferential portion 7a to the outside of the position of the flange portion 7 with respect to the blank material and forming a curved shape portion 8 bent in the plate thickness direction; After the 1st process and the 1st process, the 2nd process of bending the vertical wall part 5 and the said flange part 7 by fixing the position which becomes the top plate part 3, and the outer part of the flange part 7, And a third step of trimming.

Description

Manufacturing method of elongated flange molded part {METHOD FOR MANUFACTURING STRETCH-FLANGE-FORMED COMPONENT}

The present invention relates to a technique for producing an elongated flange molded part in which the flange part is produced with elongated flange molding by having a concave outer peripheral part that is curved as a part of the outer periphery of the top plate is inwardly recessed. will be. As such an extended flange molded part, for example, a press-formed part used as a vehicle body skeleton part can be exemplified a part having an L-shaped part or a T-shaped part in plan view. This invention is a technique suitable especially when manufacturing by press molding using the ultra high tenn material of 980 Mpa or more.

Parts having L-shaped or T-shaped portions such as a front pillar reinforcement or a center pillar reinforcement (see Figs. 6 and 7), which are car body frame parts of automobiles, are made of flat metal plates (blanks). In the case of manufacturing by press molding from ash), drawing molding or bending molding is generally employed.

Drawing molding is normally performed using the metal mold | die which consists of a punch, a die, and a blank holder, The drawing process is performed to a metal plate by making the distance between a punch and a die close, holding the circumference of a metal plate with a die and a blank holder. It is a way. In addition, bending shaping | molding is normally performed using the metal mold | die which consists of a punch, a pad, and a die, and is a method of performing a bending process by carrying out relative movement of a die in the state which pinched | interposed the metal plate with a punch and a pad.

If a curved portion such as an L-shaped portion or a T-shaped portion that is in a sharply bent shape is formed by only drawing molding as described above, cracks, wrinkles, etc. are likely to occur as the vertical wall portion increases. In particular, in recent years, in order to achieve the safety improvement and light weight of an automobile body, there exists a tendency for the intensity | strength of the metal plate used as a molding material of an automobile body to become high gradually. Since such a high strength metal sheet cannot be expected to be as soft as conventionally used soft steel sheets, measures against cracks and wrinkles during press molding have become important.

The site | part which is easy to produce especially a crack by said press molding is the extension flange molding part of a curved part. In this site | part, at the time of drawing shaping | molding, it becomes a deformation | transformation state which material flows in, while material end surface is extended in a circumferential direction.

In contrast, there is a technique described in Patent Document 1. In the technique described in this Patent Document 1, when pressing a part having an L shape, the vertical wall portion and the flange portion are molded while sliding a part of the metal material on a portion corresponding to the top plate portion in the die mold. will be.

In addition, this Patent Document 1 describes that the portion corresponding to the L-shaped lower portion of the L-shaped portion is drawn toward the vertical wall portion, so that excessive tension is generated in the flange portion, and the occurrence of cracking can be prevented. (See paragraph number 0009 of patent document 1).

Japanese Laid-Open Patent Publication No. 2012-245536

However, in patent document 1, since the metal material of the site | part corresponded to a part of top plate part is slid, the location which stress concentrates on the cross section of a metal material arises. As a result, in patent document 1, the crack of a cross section is easy to generate | occur | produce in addition to the crack of the expansion flange of a curved part. For this reason, the method of patent document 1 is difficult to apply to the steel plate with high strength.

In addition, in the case of drawing molding, since the molding load increases, when a raw material of 980 MPa or more ultrahigh tenant material is to be produced only by drawing molding, there is a concern that the draw shortage of the press machine may be a problem in drawing molding.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an extension flange molded part manufactured with extension flange molding, which can be manufactured with a low molding load while suppressing extension flange cracking. Doing.

MEANS TO SOLVE THE PROBLEM In order to solve a subject, the manufacturing method of the extension flange molded part of one Embodiment of this invention is a top plate part which has a concave outer periphery part curved like a part of outer periphery, and the said concave outer periphery of this top plate part. A method of manufacturing an elongated flange molded part comprising a vertical wall portion continuous to an edge portion and a flange portion continuously bent to the top plate portion side in succession to the vertical wall portion, wherein the flange portion is a flange material relative to a blank material. A first step of forming a curved shape in which the ridgeline extends along the position of the outer periphery of the flange portion and is bent in the plate thickness direction outward from the position, and after the first step, the position of the top plate portion is fixed After the second step of bending the vertical wall portion and the flange portion, and after the second process, the portion outside the flange portion It characterized in that it comprises a third step of reaming.

According to the embodiment of the present invention, even if a super high tenon material having a strength level of 980 MPa or more is used, in the first step, by forming the bent portion so as to surround the outer circumferential edge of the flange portion where the elongated flange crack is likely to occur, The expansion flange crack at the time of bending shaping in a 2nd process can be suppressed.

Moreover, in embodiment of this invention, since a vertical wall part is shape | molded by bending shaping | molding, without processing by drawing shaping | molding, it becomes possible to manufacture with low shaping load.

In view of the above, according to the embodiment of the present invention, even when an elongated flange molded part is produced with elongated flange molding from an ultra high tenon material having a strength level of 980 MPa or more, it is produced at a low molding load while suppressing elongated flange cracking. It becomes possible.

Here, since the said flange part is continuous through a vertical wall in the 1st concave outer peripheral part of a top plate part, and is bent to the top plate part side with respect to a vertical wall part, extension flange shaping | molding is carried out at the time of manufacture by press molding.

In addition, since the platelet (blank material) before the press molding which becomes a molding material is usually formed by punching processing or laser processing, burrs, minute scratches, etc. remain in the cross section of the material, and deformation is caused. When it is added, local stress concentration tends to occur. As a result, a crack called a stretch flange crack occurs in the cross section of the material during molding, and in the case of a super high tenon material (a high strength steel sheet having a strength level of 980 MPa or more), the crack rapidly propagates and causes large cracks. This is easy to occur.

As a countermeasure against elongated flanges, there is also a method of uniformly finishing the end face by machining or the like to prevent stress concentration. However, in the case of press molding a mass product, it is necessary to machine the end face one by one.

For this reason, in embodiment of this invention, after the 2nd process, the outer part of a flange part is trimmed and the outer periphery of a flange part is shape | molded, and parallel to this, the curved shape part formed in order to suppress the said extension flange crack is removed. Doing.

1 is a perspective view illustrating an example of an extension flange molded part according to an embodiment based on the present invention.
It is a perspective view explaining the blank material with a curved shape part which concerns on embodiment based on this invention.
It is a schematic diagram which shows the example of the curved shape part which concerns on embodiment based on this invention.
4 is a perspective view including a partial cross section of a mold used in a second step according to the embodiment of the present invention.
It is explanatory drawing of the 2nd process which concerns on embodiment based on this invention.
6 is a view showing an A pillar.
7 is a diagram illustrating a center pillar.

(Form to carry out invention)

Next, embodiment of this invention is described with reference to drawings.

In this embodiment, the case where an extension flange molded part which has a site | part which becomes an extension flange shaping | molding part is manufactured as an example is demonstrated using the super high tenth material 980 Mpa class or more as a platelet (blank material) before press molding. The manufacturing method of this invention is applicable even if the raw material consists of a metal plate whose strength is 980 Mpa or less.

Moreover, as a flange molded part which has the site | part which becomes an extended flange molded part, A pillar (refer FIG. 6) and a center pillar (refer FIG. 7) are mentioned, for example.

In addition, below, it demonstrates focusing on the part containing the site | part which becomes an extension flange shaping part in an extension flange shaping part, and only the said part is shown in each drawing. The part is referred to as "extension flange molded part 1". Moreover, also in the metal mold | die, only the site | part which molds the said site | part is shown. It goes without saying that the other parts may be molded at the same time.

As shown in FIG. 1, the extension flange shaping | molding part 1 manufactured by the manufacturing method of this embodiment has the top plate part 3 which has the concave outer peripheral part 3a curved like a part of an outer peripheral edge inwardly. The vertical wall portion 5 formed along the concave outer peripheral portion 3a of the top plate portion 3 and the vertical wall portion 5 are bent to the top plate portion 3 side in succession, and a part of the outer peripheral edge is It has the flange part 7 which has the concave outer peripheral part 7a curved inwardly. And the flange part 7 is a site | part which becomes extension flange shaping | molding at the time of press molding. In addition, although the shape of the outer periphery of the flange part 7 does not need to be a curved shape like a dent, it is normally processed to the shape along the concave outer periphery 3a.

Here, in this embodiment, the concave outer peripheral part 3a of the top plate part 3 is the 1st concave outer peripheral part 3a, and the concave outer peripheral part 7a of the flange part 7 is 2nd concave. Also called shape outer peripheral part 7a. The contour shape of this 1st concave outer peripheral part 3a and the contour shape of the 2nd concave outer peripheral part 7a are a coincidence or similar contour shape normally. Of course, each curvature shape of the curvature of the contour shape of the 1st concave outer peripheral part 3a and the curvature of the contour shape of the 2nd concave outer peripheral part 7a may differ.

Here, the profile of the curvature does not need to be a constant curvature, and it is preferable that there is no curvature steeping portion in which curvature steeps along its extending direction.

The manufacturing method of the extension flange molded part of this embodiment is equipped with the 3 processes of a 1st process, a 2nd process, and a 3rd process, and molding process is performed in this process order.

In the first step, the bent portion 8 is provided to the outer circumferential portion at the position to be the flange portion 7 with respect to the flat platelet (blank material) before press molding. That is, a 1st process is a process of manufacturing the blank material with a curved shape as shown in FIG.

In FIG. 2, the outer raw material part is abbreviate | omitted from the curved part 8, and the position used as the 2nd concave outer peripheral part 7a is shown by the dashed-dotted line. Also in other drawings, in order to make it easy to see, the outer raw material part is abbreviate | omitted from the curved-shaped part 8 suitably.

In the second step, the first concave outer peripheral portion 3a of the top plate portion 3 is formed, and the vertical wall portion 5 and the flange portion 7 are bent along the first concave outer peripheral portion 3a. Mold. That is, a 2nd process is a process of making a blank material with a curved shape part into an intermediate component.

In the third step, the bent portion 8 is trimmed from the intermediate part. That is, a 3rd process is a process of shape | molding the outer periphery of the flange part 7 and making it the said extended flange molded part.

Hereinafter, each process is explained in full detail.

[Step 1]

In a 1st process, as shown in FIG. 2, the bending part 8 is formed in the outer peripheral position rather than the position used as the flange part 7 with respect to the plate-shaped plate (blank material) before press molding. The curved portion 8 has a shape in which the ridgeline 9 extends along the second concave outer circumferential portion 7a and is bent in the plate thickness direction. The bent portion 8 of the present embodiment has a stepped end shape that is bent in the plate thickness direction, for example.

Formation of the curved shape part 8 may be formed by press molding by a die and a punch, and may be formed by another processing method.

As for the height (protrusion height of a plate thickness direction) of the step of the curved part 8 to shape | mold, 3 mm or more and 10 mm or less are preferable.

In FIG. 2, the curvature is extended along the second concave outer peripheral portion 7a such that the ridgeline 9 extends in parallel or approximately parallel to the second concave outer peripheral portion 7a or the first concave outer peripheral portion 3a. The case where the shape part 8 was formed is illustrated. However, the curved portion 8 may not extend in parallel with or substantially parallel to the second concave outer peripheral portion 7a or the first concave outer peripheral portion 3a. In addition, the curved part 8 may be formed intermittently along the 2nd concave outer peripheral part 7a. In addition, the curved part 8 may not be formed so that the ridgeline 9 may extend along the perimeter of the 2nd concave outer peripheral part 7a. Among the first concave outer circumferential portions 3a, the curved portion 8 so that the ridgeline 9 extends only along the portion where the curvature of the curvature is large, that is, the extension flange cracking is expected to occur due to molding analysis or the like, and the vicinity thereof. May be formed.

Another example of the shape of the bent portion 8 is shown in FIG. 3. In FIG. 3, although the bending shape part 8 is an example bent so that it may protrude downward, you may bend in the plate | board thickness direction so that the bending shape part 8 may protrude upward.

Here, in the first step, the top plate of the elongated flange molded part as shown in Fig. 6 or 7 with respect to the position to be the top plate portion 3 in parallel with the formation of the curved portion 8. You may press-process in order to form the uneven | corrugated shape for the others for reinforcement provided to a part. In addition, although the uneven shape formed in the position which becomes the top plate part 3 may not be the same shape as the shape given to the top plate part of a final product, it is a shape near the shape given to the top plate part 3 of a final product. It is preferable. In addition, the uneven | corrugated shape may be only the shaping | molding shape of one part of the shape given to the top plate part 3 of a final product.

Thus, when forming an uneven | corrugated shape in the position which becomes the top plate part 3 in a 1st process, it respond | corresponds to the uneven | corrugated shape in the surface which pinches the position which becomes the top plate part 3 in the metal mold | die of a 2nd process. It is good to give the shape to make. In this case, the uneven | corrugated shape provided in the 1st process has the function of the alignment and prevention of misalignment at the time of installing a blank material with a curved shape in a metal mold | die in a 2nd process.

Second process

A 2nd process is a process of bending-molding the blank material with a curved shape which provided the curved shape part 8 as shown in FIG. 2 shape | molded at the 1st process by an intermediate part.

In this 2nd process, the die 32 is punched 30 in the state which pinched | interposed the top plate part 3 of the blank material with a curved shape formed in the 1st process between the punch 30 and the pad 31. FIG. By relatively moving along, the vertical wall part 5 is bend-molded, and the flange part 7 is bent-molded so that it may bend to the top plate part 3 side.

<The second process mold>

The metal mold | die for the 2nd process used at a 2nd process is demonstrated with reference to FIG. In FIG. 4, the state in which the part of the vertical wall part 5 was shape | molded in the 2nd process is shown so that the position of the 1st concave outer peripheral part 3a may be known.

Here, in the following description, it demonstrates as the case where the curved shape part 8 is bent and formed so that it may protrude upward.

As shown in Fig. 4, the mold for the second process includes the punch 30 constituting the lower mold, the die 32 constituting the upper mold, and the blank material with the bent portion. It has the pad 31 which pinches the site | part corresponded to the top plate part 3 of this.

<Punch>

The punch 30 has the standing part 30A for top plate narrowing, and the punch extension part 30B. The punch extension part 30B may be separate from the standing part 30A. The standing part 30A for top plate narrowing becomes a 1st punch, and the punch extension part 30B comprises a 2nd punch. The punch extension part 30B has a flange facing surface 30a which can be opposed from the lower side at least in the formation position of the flange part 7 of the blank material continuously to the lower end part of the standing part 30A.

The upper surface of the standing portion 30A serves as a pinching surface for cooperating with the pad 31 to pinch the top plate portion 3 of the molding material.

Moreover, the curved surface of the same curvature as the 1st concave outer peripheral part 3a is formed in the side surface 30b of the standing part 30A, and the shape which forms the vertical wall part 5 in an extension flange shaping | molding part is formed. It is. That is, the height of the side surface of the standing part 30A is set to the same height as the vertical wall part 5.

<Pad>

The pad 31 is provided so that the upper surface of the standing part 30A in the punch 30 can be contacted easily, and corresponds to the top plate part 3 in the blank material with a curved part. The site | part is able to cooperate with the upper surface of 30 A of standing parts of the punch 30, and can cooperate. That is, the pad 31 has a shape along the first concave outer circumferential portion 3a of the top plate portion 3, and at least on the first concave outer circumferential portion 3a side of the top plate portion 3. It is possible to sandwich the part along with the punch 30 together.

As shown in FIG. 4, the position of the 1st concave outer peripheral part 3a side in the pad 31 of this embodiment is seen from an upper surface, and the side surface 30b of 30A of the standing part 30A of the punch 30 is seen. Retreat from). For this reason, as shown in FIG. 4, when the site | part corresponded to the top plate part 3 is pinched by the upper surface of the standing part 30A in the punch 30, and the pad 31, the top plate part 3 is carried out. The 1st concave outer peripheral part 3a side in the site | part corresponded to will be in the state exposed upward.

<Die>

The punch side side surface of the die 32 is a curved surface which forms the vertical wall part 5 in cooperation with the side surface 30b of the standing part 30A. The punch side side surface of the die 32 is provided with the elongate part 32a which protruded to the outer side (punch 30 side) on the upper side surface. Since the elongate part 32a contacts the upper surface of the punch 30 through a raw material, it is restrict | limited that the die 32 moves below. That is, the regulation position becomes the position of the molding bottom dead center when the die 32 is lowered. In addition, the height of the die side surface from the elongate part 32a to the lower end position is set to the height of the vertical wall part 5.

Moreover, the concave relief part 32d is formed by forming the edge part 32b in the lower surface which opposes the flange part 7 in the die 32. By having the relief portion 32d, the lower surface of the die 32 does not pinch the curved portion 8, and preferably does not contact, until the die 32 moves to the bottom dead center of molding. It is. The width of the lower surface 32c of the end portion 32b is a width equal to or less than the width of the flange portion.

In the state where the die 32 is lowered to the position of the bottom dead center, the height difference (gap) between the flange facing surface 30a of the punch 30 and the bottom surface of the relief portion 32d of the die 32 is attached to the curved portion. It is set to be equal to or greater than the height of the bent portion 8 formed in the blank material.

By setting in this way, the curved shape part 8 is arrange | positioned in the space | gap (concave part) which arises by the relief part 32d of the die 32, and the curved shape part 8 is during the bending shaping | molding of a 2nd process. There is no arrest or coordination. As described above, by freely deforming the portion including the bent portion 8 during bending, the concentration of stress in a specific portion of the flange portion can be reduced, and the occurrence of cracking can be further prevented.

In addition, when the curved part 8 is convex toward the flange facing surface 30a side of the punch 30, what is necessary is just to set the recessed shape for relief parts mentioned above on the flange facing surface 30a side.

With reference to FIG. 5, the operation | movement of the 2nd process metal mold | die is demonstrated about the 2nd process using the 2nd process metal mold | die comprised as mentioned above.

FIG. 5 (a) shows a state in which the top plate portion 3 of the blank material with the bent portion is pinched by the punch 30 and the pad 31, and FIG. 5 (b) shows that the die 32 is relatively press-formed. The state is shown when moving to the point.

First, as shown in Fig. 5 (a), the top plate portion 3 of the blank material with the bent portion is placed on the upper surface of the punch 30 and sandwiched by the punch 30 and the pad 31. In addition, the pad 31 is not disposed on the entire surface of the portion corresponding to the top plate portion 3 in the extension flange molding portion, but is disposed on the first concave outer peripheral portion 3a of the punch 30. It is arrange | positioned in the position slightly shifted inward from the side surface which has a corresponding curvature.

In this state, the first concave outer periphery 3a, by moving the die 32 relative to the flange facing surface 30a along the side of the punch 30 to the position shown in FIG. 5 (b), The vertical wall portion 5 and the flange portion 7 are bent.

That is, by the relative movement of the die 32 in a 2nd process, the part of the 1st concave outer peripheral part 3a is first bent-molded by the blank material with a curved shape. Subsequently, the portion serving as the vertical wall portion 5 is bent downward in order from the upper side continuous to the first concave outer peripheral portion 3a, and the flange portion 7 side of the blank material is the punch extension portion ( In contact with the flange facing surface 30a of 30B, the boundary between the lower end of the vertical wall portion 5 and the flange portion 7 is bent. As described above, in the present embodiment, bending is sequentially applied continuously from the top plate portion side.

At this time, the site | part (outside from the position which becomes a flange part) in which the curved shape part 8 in the blank material with a curved shape part is formed is extended flange shaping | molding, and the tensile stress of a peripheral direction acts. However, since the ridgeline 9 of the curved portion 8 exists in a continuous shape in the circumferential direction unlike the cross section of the platelet before press molding, the site does not have a starting point of cracking and cracking occurs. Difficult to do In addition, since the ridgeline 9 of the curved portion 8 is a continuous shape in the circumferential direction, since the uniform tensile stress is added to the site without stress concentration, the stretched flange portion also in this point. Cracking is unlikely to occur.

Moreover, since the curved part 8 of this embodiment extends along the 2nd concave outer peripheral part 7a in planar view, the tensile stress acting on the curved part 8 can be made more uniform. Can be.

In addition, in the 1st process, the bending shape part 8 prescribed | regulated above is shape | molded at least in the vicinity of the curved part of the flange part extended and shape | molded, and the part which becomes the 2nd concave outer peripheral part 7a becomes at the time of a 2nd process. Even when the extension flange is subjected to deformation, the deformation is easily dispersed by the shape rigidity of the bent portion 8, and it is possible to prevent the deformation from being concentrated at the portion that becomes the second concave outer peripheral portion 7a.

In addition, by shape | molding the curved shape part 8 prescribed | regulated in the 1st process, when the 2nd concave outer peripheral part 7a receives the extension flange deformation at the 2nd process, the curved shape part 8 is By forming it at a constant height, the part which becomes the 2nd concave outer peripheral part 7a becomes flat, and the difference in the length of a line can be made. Therefore, the tensile stress in the circumferential direction that is strong on the second concave outer peripheral portion 7a is hard to act.

In this way, by uniformizing the tensile stress acting on the portion that becomes the second concave outer circumferential portion 7a, the uniform stress acts on the outer end surface of the curved portion 8, too. Even if the scratches and the like remain, the stress concentration is alleviated, and the crack suppression effect can also be obtained in this regard.

In the middle of forming, since the portion including the curved portion 8 is not constrained by a mold, it can be freely deformed (moved or reliefd) three-dimensionally, and in this respect, the cross section of the part under molding It is possible to further alleviate the tensile stress acting on the concentration.

In this way, the intermediate part is molded without cracking.

Here, although the case where the curved shape part 8 protruded upward was demonstrated, when the curved shape part 8 protrudes downward, the curved shape part is relief | released to the punch extension part 30B side of the punch 30. As shown in FIG. You may form a recessed part shape. In addition, you may form the recessed part for relief of a curved part in the surface which the punch extension part 30B of the punch 30 and the die 32 oppose.

[Third process]

In a 3rd process, the site | part of the outer side of the flange part 7 of an intermediate part is trimmed, and the 2nd concave outer peripheral part 7a is formed. As a result, an extension flange molded part including an extension flange molded part is manufactured. The bent portion 8 is included in the trimmed portion.

As described above, in the present embodiment, the bent portion 8 is formed in the first step, and the blank material with the bent portion is formed into an intermediate part in the second step, and the intermediate part is formed in the third step. In order to trim the part of the outer side of the flange part 7 in the case, even if it uses 980 MPa or more ultrahigh tenth grade material as a platelet before press molding, cracking can be suppressed and the extension flange which preferably contains an extension flange shaping | molding part is carried out. Molded parts can be produced.

[Effect of this embodiment]

(1) With respect to the blank material, at the position outside of the flange portion 7, the ridgeline 9 extends along the second concave outer circumferential portion 7a and bends in the plate thickness direction to form a bent portion 8. And a second step of bending the vertical wall portion 5 and the flange portion 7 by fixing the position to be the top plate portion 3 after the first process.

According to this configuration, even if a super high tenon material having a strength level of 980 MPa or more is used, the vertical wall portion 5 can be formed by the bending process of the second step, and the second concave outer circumference easily prone to cracking of the extension flange. By forming the bent portion 8 in advance along the edge 7a, it is possible to suppress the elongation flange cracking at the time of bending molding in the second step.

In addition, since the vertical wall portion is molded by bending molding without processing by drawing molding, it is possible to manufacture with a low molding load.

In view of the above, according to the present embodiment, even in the case where an elongated flange molded part is produced from an elongated high strength material having a strength level of 980 MPa or more with elongated flange molding, it is possible to manufacture with a low molding load while suppressing elongated flange cracking. Become.

(2) After a 2nd process, the 3rd process of trimming the site | part of the outer side of the said flange part 7 is provided.

If the platelet (blank material) before press molding is trimmed by punching or laser processing, burrs, small scratches, etc. remain in the cross section of the material, so that local stress concentration is likely to occur when deformation is applied. It is. For this reason, a crack called elongation flange crack occurs in the cross section of the material during molding, and in the case of a super high tensile steel (high strength steel sheet having a strength level of 980 MPa or more), the crack propagates rapidly and large cracks are likely to occur.

On the other hand, by trimming the outer part of the flange part 7 after a 2nd process and shaping | molding the outer periphery of the flange part 7, it becomes hard to produce an extension flange crack in the cross section of the flange part 7 further.

(3) Moreover, the relief part 32d which reliefs the curved part 8 is formed in the metal mold | die for a 2nd process.

According to this structure, since the site | part containing the curved part 8 is not restrained by the metal mold | die for a 2nd process during shaping | molding, it can freely deform (move or relief) three-dimensionally, In view of this, the tensile stress acting on the end face of the part during molding can be further relaxed.

(4) The height of the step of the bent portion 8 is 3 mm or more and 10 mm or less.

By defining the height of the bent portion 8 in this range, even if a super high tenon material having a strength level of 980 MPa or more is used, it is possible to more reliably suppress the expansion flange cracking.

Example

Invention Example 1

When manufacturing a component of the same shape as A-pillar shown in FIG. 7 using a 980 Mpa grade cold-rolled steel sheet (plate thickness 1.6 mm) as a blank material, 1st process, 2nd process, 3rd shown by the said embodiment. The molded article of Inventive Example 1 was manufactured by a three-step manufacturing method which passes through a process.

That is, the processing process formed the curved part 8 in the 1st process as mentioned above. Next, in the second step, the first concave outer peripheral portion 3a, the vertical wall portion 5, and the flange portion 7 were successively bent and formed. Then, as a 3rd process, the site | part on the outer side of the flange part 7 was trimmed and it was set as the molded article of the example 1 of this invention. In addition, the height of the vertical wall portion was 100 mm.

On the other hand, the vertical wall part was formed only by the drawing shaping | molding of one process, and the component of the same shape as the A pillar shown in FIG. 6 was trimmed after that, and the molded article of the comparative example 1 was manufactured. In addition, in the comparative example 1, the bending shaping | molding part was not formed.

The stretched flange parts of the molded article of Example 1 and the molded article of Comparative Example 1 were compared. As for the evaluation result, in this invention example 1, the crack generate | occur | produced in the site | part shown in FIG.

As mentioned above, when manufacturing A filler, the advantage over Comparative Example 1 of Inventive Example 1 was revealed.

Invention Example 2

When manufacturing the parts of the same shape as the center pillar shown in FIG. 6 using the 1180 Mpa grade cold rolled steel sheet (plate thickness 1.6 mm) as a blank material, 1st process, 2nd process, and 3rd shown by the said embodiment. The molded article of Inventive Example 2 was manufactured by a three-step manufacturing method which passes through a process.

That is, the processing process formed the curved part 8 in the 1st process as mentioned above. Next, at the 2nd process, it bend | molded continuously in the order of the 1st concave outer peripheral part 3a, the vertical wall part 5, and the flange part 7 in order. Then, as a 3rd process, the site | part of the outer side of the flange part 7 was trimmed, and it was set as the molded article of the example 2 of this invention. In addition, the height of the vertical wall portion was 100 mm.

On the other hand, the vertical wall part was formed only by the drawing shaping | molding of one process, and the parts of the shape same as the center pillar shown in FIG. 7 were trimmed after that, and the molded article of the comparative example 2 was manufactured. In addition, in the comparative example 2, the bending shaping | molding part was not formed.

The stretched flange parts of the molded article of Example 2 and the molded article of Comparative Example 2 were compared. As for the evaluation result, in this invention example 2, the crack generate | occur | produced in the site | part shown in FIG.

As mentioned above, when manufacturing a center pillar, the superiority with respect to the comparative example 2 of this invention example 2 was revealed.

As mentioned above, all the content of the Japanese patent application 2015-169227 (August 28, 2015 application) which this application claims priority forms part of this indication by reference.

Although the description has been made here with reference to a limited number of embodiments, the scope of rights is not limited to them, and modifications of the embodiments based on the above disclosure are obvious to those skilled in the art.

1: flange forming part
3: top plate
3a: first concave shape outer periphery
5: vertical wall portion
7: flange
7a: second concave shape outer periphery
8: bend shape
9: ridge
30: Punch
30A: standing portion for first plate narrowing (first punch)
30B: punch extension portion (second punch)
31: Pad
32: Die
32d: relief part

Claims (3)

A top plate portion having a concave outer circumferential portion curved as a part of the outer circumference inwardly, a vertical wall portion continuous to the concave outer circumference portion of the top plate portion, and a flange portion continuously bent toward the top plate portion side in the vertical wall portion As a manufacturing method of an extension flange molded part which manufactures an extension flange molded part provided with:
A first step of forming a bent shape portion in which a ridgeline extends and is bent in a plate thickness direction along a position where the outer edge portion of the flange portion extends outward from the position of the flange portion with respect to the blank material;
A second step of bending the vertical wall portion and the flange portion by fixing a position to be the top plate portion after the first step;
And a third step of trimming a portion outside the flange portion after the second step. The method of claim 1,
In the second step, the concave outer peripheral portion, the vertical wall portion, and the flange portion are sequentially successively bent by relatively moving the die along the punch in a state where the top plate portion is sandwiched with a punch and a pad. A method for producing an elongated flange molded part, characterized in that the molding. The method according to claim 1 or 2,
The said 2nd process clamps and fixes the position which becomes the said top plate part with a punch and a pad, bending the said vertical wall part and the said flange part with a die, and has a surface which opposes the said die by sandwiching a blank material. With a second punch,
A concave relief portion capable of avoiding contact with the curved portion is formed on a surface facing the blank material of the die and the second punch, at least on the protruding side of the curved portion due to the bending of the curved portion. The manufacturing method of the extension flange molded part characterized by the above-mentioned.

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