JP7000459B2 - Blank material, press forming method and press forming apparatus for the blank material - Google Patents

Description

The present invention relates to a blank material having an opening, a press forming method for performing draw forming on the blank material, and a press forming apparatus thereof.

Conventionally, for example, the side panel of an automobile is produced by press-molding a metal plate material, and this side panel is molded by deep drawing molding, and the entire circumference of the pre-molded side panel and the same pre-molding are performed. The entire circumference of the edge of the opened opening was sandwiched between blank holders to perform deep drawing.

In recent years, in order to enhance the design of automobiles, for example, it is known that the upper part of the rear wheel arch in the side panel is formed more convex by deep drawing. When such a side panel is deep-drawn from a single plate, especially in the opening for the rear door preformed on the rear wheel arch side, a straight portion that is close to the convex shape of the upper part of the rear wheel arch in this opening. Is a place where tension is required because the amount of material flowing into the convex shape of the upper part of the rear wheel arch is large and wrinkles are likely to occur during molding.

Further, in the opening for the rear door, the R portion in the vertical direction is stretched by the inflow of the material and cracks are likely to occur, so that it is required to reduce the amount of stretching of the material. Therefore, different correspondence is required between the R portion and the straight portion at the opening. There is also a method of forming the rear wheel arch and the side panel separately and joining them by welding or the like, but in this case, there is a problem that the manufacturing process increases and the manufacturing cost increases.

For example, in the press molding method disclosed in Japanese Patent No. 3814711, when forming a recess from a metal plate material, a slit is formed in advance along the entire circumference inside the scrap portion in the molded product. Since the force acts only on the outside of the slit when drawing is performed, it is possible to perform molding without causing cracks or the like at the end of the slit.

However, in the above-mentioned press molding method, the recess is drawn and molded so that the bead is installed only in the inner portion of the central portion of one side of the scrap portion, and tension can be applied to the straight portion where tension is required. There is a problem that it is difficult.

Further, in the press molding apparatus disclosed in Japanese Patent Publication No. 63-145519, a storage groove is formed in a position near the blank holder arranged on the outer peripheral side of the lower punch, and a floating punch is formed in this storage groove. Is provided so as to be movable up and down via a cylinder. Then, with the work placed on the upper surface of the punch, the die descends from above, the outer edge of the work is held by the die and the blank holder, and then the die further descends to come into contact with the floating punch. As a result, the work is drawn and formed between the die and the lower mold while holding the work.

The present invention has been made in connection with the above proposal, and it is possible to obtain a high-quality molded product while preventing the occurrence of cracks in the opening in drawing molding of a blank material having an opening. It is an object of the present invention to provide a blank material, a press forming method for the blank material, and a press forming apparatus.

In order to achieve the above object, the present invention is a blank material which is drawn by a press forming apparatus to become a body panel of an automobile.
It has an opening consisting of an arc portion provided in the vertical direction of the body panel and a substantially linear connecting portion provided in the front-rear direction of the body panel substantially orthogonal to the arc portion and connected to the arc portion.
The connecting portion is characterized by being provided with a tension adjusting portion that extends toward the inside of the opening and can adjust the tension applied to the outside during molding.

According to the present invention, in a blank material drawn by a press forming apparatus, a substantially linear connection between an arc portion provided in the vertical direction of the body panel and the arc portion provided in the front-rear direction of the body panel and connected to the arc portion. An opening consisting of a portion is provided, and a tension adjusting portion extending toward the inside of the opening is provided in the connecting portion to adjust the tension applied to the outside of the connecting portion when drawing molding is performed. It is possible.

Therefore, even when deep drawing is performed with a blank material having an opening, by appropriately adjusting the inflow amount to the outside of the connecting portion formed in a substantially linear shape with respect to the arc portion, the front and back of the opening can be adjusted. It is possible to obtain a high-quality molded product by preventing the occurrence of wrinkles on the convex molded portion provided in the direction.

Further, in order to prevent wrinkles due to the amount of material flowing into the convex shape of the upper part of the rear wheel arch during molding, tension adjusting portions may be formed for each set of connecting portions. As a result, the tension can be applied by gripping the tension adjusting portion with the (first and second) blank holders of the press forming apparatus, so that the occurrence of wrinkles can be prevented.

Further, in the opening for the rear door, in order to prevent the occurrence of cracks due to the material inflow of the arc portion (R portion), the arc portion is made smaller than the molded arc portion of the molded body in which the arc portion is formed, and the arc portion is made smaller. , It is preferable to form them in a close shape. This makes it possible to reduce the amount of elongation of the material in the arc portion and prevent the occurrence of cracks.

Furthermore, the present invention is a press forming method for performing drawing forming on a blank material having an opening portion consisting of an arc portion and a substantially linear connecting portion connected to the arc portion.
The peripheral edge of the opening is pressed and sandwiched by the first blank holder provided in the lower mold and the upper mold.
An arc portion outside the holding portion of the blank material sandwiched between the first blank holder and the upper mold is pressed between the second blank holder provided on the outside of the first blank holder and the upper mold. It is characterized in that the tension adjusting portion extending from the connecting portion toward the inside of the opening is sandwiched between the upper mold and the first blank holder to form a bead .

According to the present invention, when drawing and forming a blank material having an opening, the peripheral edge of the opening is pressed and sandwiched between the first blank holder provided in the lower mold and the upper mold. , The arc portion of the opening that is outside the sandwiching portion of the blank material sandwiched by the first blank holder and the upper mold is between the second blank holder provided on the outside of the first blank holder and the upper mold. Pressurize with and hold.

Therefore, while the peripheral edge of the opening is sandwiched between the upper mold by the first blank holder, the arc portion outside the sandwiched portion is sandwiched between the upper mold and the second blank holder provided on the outside thereof. It becomes possible.

As a result, by forming the opening so that the arc portion is on the outside of the first blank holder, the amount of inflow to the outside during molding is suppressed and the occurrence of cracks is prevented, while the second blank holder ensures. It becomes possible to perform draw forming. Further, by sandwiching the tension adjusting portion extending from the connecting portion toward the inside of the opening between the upper mold and the first blank holder to form a bead, tension can be applied to the blank material even more effectively. It becomes possible to grant.

Further, the present invention is a press forming apparatus for drawing and forming a blank material having an opening including an arc portion and a substantially linear connecting portion connected to the arc portion.
With the upper mold
The lower mold, which is arranged so as to face the upper mold and has a mounting surface on which the blank material is placed,
A first blank holder that is placed facing the upper mold and sandwiches the peripheral edge of the opening in the blank material together with the upper mold.
A second blank holder arranged outside the first blank holder and sandwiching an arc portion outside the holding portion of the blank material sandwiched between the first blank holder and the upper mold between the upper mold and the first blank holder.
Equipped with
The first blank holder and the upper die are provided with a bead that pressurizes and holds the tension adjusting portion extending inward from the connecting portion of the blank material.

According to the present invention, in a press forming apparatus for drawing and forming a blank material having an opening composed of an arc portion and a connecting portion, the first is to face the upper mold and sandwich the peripheral edge of the opening in the blank material together with the upper mold. A blank holder and a second blank holder arranged outside the first blank holder are provided, and the second blank holder is outside the holding portion of the blank material sandwiched between the first blank holder and the upper die. The arc portion is provided so as to be sandwiched between the upper mold and the upper mold.

Therefore, when drawing and forming the blank material, the outward tension applied to the connection portion at the opening is appropriately adjusted by the bead of the tension adjusting portion, and at the same time, the arc portion is subjected to the second blank holder. It is possible to adjust the tension to the outside by sandwiching it through.

As a result, when drawing is performed on a blank material having an opening, the tension of the connection portion where cracks are unlikely to occur even if the inflow amount of the blank material is large, and the cracks occur when the inflow amount is large. By appropriately balancing the tension adjustment of the arc portion, which is easy to do, it is possible to obtain a high-quality molded product with a deep drawing while preventing the occurrence of wrinkles on the peripheral edge of the connecting portion and the occurrence of cracks on the peripheral edge of the arc portion during molding. Will be.

Further, the second blank holder may be formed in an annular shape. As a result, the tension adjusting portion at the connecting portion is gripped by the second blank holder, and the tension can be applied even more effectively.

Furthermore, the bead may be extended along a direction substantially orthogonal to the extending direction of the tension adjusting portion. As a result, tension can be evenly applied to the blank material.

It is a front view of the side outer panel for an automobile molded by the press molding apparatus which concerns on embodiment of this invention. It is a front view which shows the blank material before the side outer panel of FIG. 1 is molded. It is an enlarged plan view which shows the vicinity of the 2nd blank hole of the molded blank material. It is a top view of the lower mold, the 1st and 2nd blank holders constituting a press forming apparatus. It is an enlarged plan view of the 2nd holder part and the 2nd blank holder of the 1st blank holder shown in FIG. FIG. 5 is a cross-sectional view taken along the line VI-VI of FIG. FIG. 5 is a cross-sectional view taken along the line VII-VII of FIG. FIG. 8A is a conceptual diagram showing a cross-sectional change before and after molding when the straight line portion of FIG. 2 is molded, and FIG. 8B compares the arc portion before molding and the molded arc portion after molding in FIG. It is a conceptual diagram for.

The press forming apparatus 10 is for performing press forming on the blank material 14, and here, the press forming apparatus 10 makes the side outer panel (body panel) 12 for an automobile a steel plate that becomes the blank material 14. A case of molding from is described.

First, the side outer panel 12, which is a molded product, will be described with reference to FIG. The side outer panel 12 constitutes, for example, a side portion of a body in an automobile, and is formed on a front pillar portion 16 formed on the front side (arrow A direction) along the vehicle direction and on the rear side (arrow B direction). The rear pillar portion 18 is formed, the center pillar portion 20 formed in a substantially central portion in the vehicle direction, the roof portion 22 connecting the front pillar portion 16, the center pillar portion 20, and the upper ends of the rear pillar portion 18, and the front pillar. A side sill portion 24 connecting the lower ends of the portion 16, the center pillar portion 20 and the rear pillar portion 18 is included.

Further, the side outer panel 12 is formed with a first door opening 26 surrounded by a front pillar portion 16, a center pillar portion 20, a roof portion 22, and a side sill portion 24, and the center pillar portion 20 and a rear pillar portion. 18. A second door opening 28 surrounded by the roof portion 22 and the side sill portion 24 is formed, and on the rear side (arrow B direction) of the second door opening 28, above the rear tire (not shown). The rear fender portion 30 is formed at such a position.

Next, the blank material 14 to be press-molded will be described with reference to FIGS. 2 and 3.

The blank material 14 is made of, for example, a steel plate having a certain plate thickness, and is formed into long pieces along the front-rear direction (arrows A and B directions) of the vehicle. Further, the blank material 14 has a first blank hole 32 formed on one end side (direction of arrow A) and serving as a first door opening 26 of the molded product (side outer panel 12), and the other end side (arrow). A second blank hole (opening) 34 formed in the B direction) and serving as a second door opening 28 of the molded product is formed, and the first blank hole 32 and the second blank hole 34 are in the front-rear direction of the vehicle. The doors are opened at predetermined intervals along (arrows A and B).

The first blank hole 32 is formed, for example, in a substantially triangular cross section, while the second blank hole 34 is a substantially oval circle elongated in the vertical direction (arrow C direction) substantially orthogonal to the front-rear direction of the blank material 14. It is formed in a shape. The second blank hole 34 is a set of straight portions connecting the first and second openings 36 and 38, which are semicircularly opened at the upper and lower portions, respectively, and the first opening 36 and the second opening 38. (Connecting portions) 40a and 40b, and a set of tension adjusting portions 42a and 42b extending inward from the straight portions 40a and 40b.

The first opening 36 has an arc portion 44a formed upward and curved in an arc shape in a cross section upward, and the second opening 38 is formed downward with respect to the first opening 36. It has an arc portion 44b that is curved downward in a circular arc shape, and as shown in FIG. 3, the arc portions 44a and 44b are only slightly with respect to the molding arc portion 46 of the molded product after molding. It is formed so as to be inside in the radial direction.

In other words, the arc portions 44a and 44b have a diameter dimension smaller than that of the molding arc portion 46 of the molded product, and one arc portion 44a is close to the upper molding arc portion 46. The other arc portion 44b is formed so as to be close to the lower forming arc portion 46.

That is, the second blank hole 34 is formed so that the first opening 36 and the second opening 38 face each other in the vertical direction, and one straight line portion 40a and the other straight line portion 40b are formed in the front-rear direction (arrow A). , B direction), formed between the first and second openings 36, 38 so as to face each other.

One straight line portion 40a connects one end of the arc portion 44a of the first opening 36 and one end of the arc portion 44b of the second opening 38, and the other straight portion 40b is the arc in the first opening 36. The other end of the portion 44a and the other end of the arc portion 44b in the second opening 38 are connected.

The tension adjusting portions 42a and 42b extend inward to each other so as to be substantially orthogonal to the set of straight portions 40a and 40b, and are formed in the vertical direction (arrow C direction) with a predetermined width and the straight portions. It protrudes from 40a and 40b by a predetermined length. In other words, the set of tension adjusting portions 42a and 42b extend so as to approach each other toward the center of the second blank hole 34.

Next, the press forming apparatus 10 that press-molds the blank material 14 described above will be described.

This press forming apparatus 10 is for performing so-called draw forming, and as shown in FIGS. 4 to 7, a lower die 48 as a forming die for deep drawing a work which is a blank material 14 and an illustration thereof are shown. It has an upper mold 50 that approaches or separates from the lower mold 48 under the action of an elevating mechanism, and first and second blank holders 52 and 54 for holding the blank material 14.

The lower mold 48 is a fixed mold fixed to a base or the like (not shown), the outer edge portion 56 (see FIGS. 6 and 7) has a convex shape, and the lower mold 48 has a concave molding recess 58 in a substantially central portion. ing. The upper mold 50 is a movable mold that can be displaced in the vertical direction (in the direction of arrow D in FIGS. 6 and 7), has a molding protrusion 60 that can be inserted into the molding recess 58 of the lower mold 48, and is formed thereof. A protruding portion 62 is formed on the lower surface of the convex portion 60 at a position facing the top of the first blank holder 52.

Then, when the upper mold 50 and the lower mold 48 are closed, the molding convex portion 60 of the upper mold 50 enters the molding concave portion 58 of the lower mold 48, whereby the molded product is placed between the two. A cavity having the shape of (side outer panel 12) is formed.

The first blank holder 52 is provided so as to be movable in the vertical direction in the molding recess 58 of the lower mold 48, and the first holder portion 64 for forming the vicinity of the first blank hole 32 of the blank material 14 and the blank material 14 are formed. It has a second holder portion 66 for forming the vicinity of the second blank hole 34. The first and second holder portions 64 and 66 are formed so as to be separated from each other along the front-rear direction (arrow A direction) of the lower mold 48 (see FIG. 4).

Further, as shown in FIGS. 6 and 7, the first and second holder portions 64 and 66 are supported by a plurality of cushion pins 68 whose lower ends extend from urging means (not shown), and the first and second holder portions 64 and 66 are supported. The first blank holder 52 including the second holder portions 64 and 66 is displaced in accordance with the forward (upward) and backward (downward) movements of the cushion pin 68 along the vertical direction (arrow D direction).

Further, in the first and second holder portions 64 and 66, a top portion facing the upper mold 50 is formed in a substantially planar shape, and an annular groove portion 70 is formed in the vicinity of the outer edge portion on the top portion of the first holder portion 64. On the other hand, a pair of groove portions 72 extending substantially in the vertical direction of the lower mold 48 are formed on the top of the second holder portion 66. Then, when the blank material 14 is formed between the upper mold 50 and the first blank holder 52, the protruding portion 62 (see FIG. 6) of the upper mold 50 is the annular groove portion 70 with the blank material 14 sandwiched between them. The bead 74 is formed in the vicinity of the first and second blank holes 32 and 34 of the blank material 14 by being inserted into the groove portion 72, respectively.

The bead 74 formed by the first holder portion 64 is formed in an annular shape corresponding to the annular groove portion 70, and the bead 74 formed by the second holder portion 66 is formed in a straight line corresponding to the pair of groove portions 72, respectively. (See FIG. 3).

The second blank holder 54 is formed in an annular shape so as to surround the second holder portion 66 of the first blank holder 52, and a plurality of cylinders 76 are provided at the lower portion and supported by the cylinder rod 78. Further, the molding surface 54a of the second blank holder 54 facing the upper mold 50 is formed so as to be higher from the inner side of the first blank holder 52 toward the outer side of the lower mold 48 in the radial direction.

Then, the second blank holder 54 moves forward and backward (up and down) in the vertical direction with respect to the lower mold 48 as the cylinder rod 78 of the cylinder 76 moves forward (up) and backward (down).

The press forming apparatus 10 according to the embodiment of the present invention is basically configured as described above, and then a forming method for forming the blank material 14 will be described.

First, the blank material 14 is arranged between the lower mold 48 and the upper mold 50 which have been opened. At this time, the first and second blank holders 52 and 54 are at the top dead center positions where they are most raised under the urging action of the cushion pin 68 and the cylinder 76, respectively, and the blank material 14 is the first and second blanks. The holders 52 and 54 are placed so as to be in contact with the tops (mounting surfaces) of the holders 52 and 54.

Further, the blank material 14 is placed so that the first blank hole 32 faces the first holder portion 64 of the first blank holder 52, and the straight portions 40a and 40b of the second blank hole 34 and the tension adjusting portion 42a, 42b is placed so as to face the second holder portion 66, and the arc portions 44a and 44b of the first and second openings 36 and 38 face the second blank holder 54.

Then, in order to perform press molding, the upper mold 50 descends and approaches the lower mold 48 under the driving action of an elevating mechanism (not shown), and the molding convex portion 60 of the upper mold 50 molds the lower mold 48. By entering the recess 58, the surface of the molded convex portion 60 facing the first blank holder 52 first abuts and presses against the portion of the blank material 14 placed on the first blank holder 52. ..

As a result, the first blank holder 52 receives the pressing force from the upper mold 50 and descends while pushing down the cushion pin 68, and the blank material 14 is moved to the annular groove portion of the first holder portion 64 by the protruding portion 62 of the upper mold 50. When pushed into 70, it is plastically deformed to form an annular bead 74. At the same time, the tension adjusting portions 42a and 42b of the second blank hole 34 are sandwiched between the upper die 50 and the top of the second holder portion 66, so that the tension adjusting portion is as shown in FIG. Two linear beads 74 that are recessed downward are formed in the portions 42a and 42b. The bead 74 is formed along the width direction of the tension adjusting portions 42a and 42b which are the vertical directions of the blank material 14, respectively.

When the upper mold 50 is further lowered, as shown in FIG. 6, drawing is performed in the vertical direction (arrow D direction) between the outer edge portion 56 of the molding convex portion 60 and the inner edge portion of the molding recess 58, and the upper die 50 is drawn. Along with this, the inside of the blank material 14 is pulled toward the outside, which is the rear side of the vehicle (direction of arrow B), with a predetermined tension. At this time, the straight portions 40a and 40b of the second blank hole 34 have a predetermined tension by the tension adjusting portions 42a and 42b sandwiched between the upper mold 50 and the first blank holder 52 via the bead 74. The amount of the blank material 14 inflowing into the vehicle front-rear direction (arrows A and B) is adjusted accordingly.

Further, as shown in FIG. 8A, in the straight portions 40a and 40b, the amount of deformation in the vertical direction (arrow D direction) is large due to the upper die 50 and the lower die 48, but the outside of the blank material 14 (arrow E). Since the amount of inflow into the direction) is large, cracks do not occur during molding.

At the same time, as the upper mold 50 is lowered, as shown in FIG. 7, the cylinder rod 78 of the cylinder 76 is pressed downward, the second blank holder 54 is pushed down through the blank material 14, and the second blank is pushed down. The arc portions 44a and 44b of the first and second openings 36 and 38 of the holes 34 are sandwiched between the first and second openings 36 and 38 and pressed with the second blank holder 54, so that drawing is performed on the forming surface 54a.

At this time, as shown in FIG. 3, the arc portions 44a and 44b of the first and second openings 36 and 38 in the second blank hole 34 are radially relative to the molded arc portion 46 after the arc portions 44a and 44b have been molded in advance. Since the shape is formed so as to be close to each other, the inflow amount of the blank material 14 to the outside in the radial direction with respect to the second blank hole 34 is small.

Here, the change in the inflow amount of the blank material 14 at the time of molding in the arc portion 44a of the second blank hole 34 described above will be briefly described with reference to FIG. 8B. In FIG. 8B, the first arc portion from which a part of the arc portion 44a before molding is taken out is referred to as R1, and the molded arc portion 46 obtained by forming the first arc portion R1 by press molding is designated as the second arc portion R2. There is.

As can be understood from FIG. 8B, the length of the first arc portion R1 which is a part of the arc portion 44a is L1, and the first arc portion R1 is formed to be extruded outward by a predetermined distance in the radial direction. It expands and becomes the second arc portion R2 of the molded arc portion 46. The second arc portion R2 has a length L2 longer than that of the first arc portion R1.

That is, when the inflow amount of the blank material 14, which is the extrusion distance in the radial direction, is F1, the difference between the length L2 of the second arc portion R2 after molding and the length L1 of the first arc portion R1 before molding. Is L2-L1.

On the other hand, the amount of the blank material 14 inflowing outward in the radial direction with respect to the first arc portion R1 is large, for example, at a position radially inside the first arc portion R1 before molding. When the 3 arc portion R1'(see the broken line in FIG. 8B) is set, the inflow amount F2 (distance) larger than the above is formed in order to form the second arc portion R2 from the third arc portion R1'. Moreover, the difference between the length L1'of the third arc portion R1'and the length L2 of the second arc portion R2 after molding is L2-L1'.

Therefore, the length of the second arc portion R2 is longer than the length L2 of the second arc portion R2 when molded with the inflow amount F1. The difference from L2 becomes longer by the amount of L1-L1'.

In the arc portion 44a, as shown in FIG. 8B, as the amount of inflow of the blank material 14 to the outside in the radial direction during molding increases, cracks are more likely to occur during molding. Therefore, it is understood that it is preferable to set the shape of the arc portion before molding so that the inflow amount is as small as possible with respect to the second arc portion R2 after molding, that is, the separation distance in the radial direction is small. ..

In the above description, the arc portion 44a of the first opening 36 has been described, but since the same applies to the arc portion 44b of the second opening 38, detailed description thereof will be omitted.

In this way, when the blank material 14 is formed, the tension applied to the straight portions 40a and 40b of the second blank hole 34 is adjusted by the tension adjusting portions 42a and 42b to control the tension in the vehicle front-rear direction. Moreover, the vertical tension applied to the arc portions 44a and 44b of the first and second openings 36 and 38 is controlled by the second blank holder 54.

Although shown briefly in each figure, in reality, the inner edge of the second blank hole 34 in the blank material 14 is given a three-dimensional shape, and in particular, as the molding progresses, the rear side of the vehicle A tensile force directed toward the rear side (direction of arrow B) acts on one straight line portion 40b (direction of arrow B). Due to this tensile force, the blank material 14 is deeply drawn in the width direction which is substantially orthogonal to the vehicle direction, and has a three-dimensional shape from the second door opening 28 to the rear fender portion 30 in the molded product. Can be done.

Then, when the upper die 50 reaches the bottom dead center where the upper die 50 is lowered to the maximum, the blank material 14 sandwiched between the lower die 48, the first and second blank holders 52, 54 and the upper die 50 is formed into the molding recess 58. And, it is molded into a molded product (side outer panel 12) corresponding to the shape of the cavity formed by the molding convex portion 60 that has entered the molding recess 58.

After that, the upper mold 50 is separated from the lower mold 48, the first and second blank holders 52, 54 to open the mold under the action of an elevating mechanism (not shown), and the molded product is removed from the press molding device 10 to remove the blank material. The press molding of 14 is completed, and the side outer panel 12 which is a molded product is obtained. By trimming the molded product, the side outer panels 12 having the first and second door openings 26 and 28 are obtained.

As described above, in the present embodiment, in the press forming apparatus 10 for drawing and forming the blank material 14 having the first and second blank holes 32 and 34, the first blank is formed in the forming recess 58 in the lower mold 48. A holder 52 and an annular second blank holder 54 are provided on the outer peripheral side of the second holder portion 66 of the first blank holder 52 arranged on the rear side of the vehicle, and the second blank hole 34 has a semicircular cross section. The first and second openings 36, 38 of the above, and a set of straight portions 40a, 40b connecting the first opening 36 and the second opening 38, and the straight portions 40a, 40b have a first. 2 A set of tension adjusting portions 42a and 42b extending toward the inside of the blank hole 34 is provided.

As a result, when drawing and forming the blank material 14, the bead 74 is formed by sandwiching the tension adjusting portions 42a and 42b between the upper mold 50 and the first blank holder 52, whereby the straight portion of the second blank hole 34 is formed. It is possible to suitably adjust the tension applied to the outside with respect to 40a and 40b. As a result, even when the inflow amount of the blank material 14 in the vehicle front-rear direction (arrows A and B directions) is increased, the tension thereof is appropriately adjusted so that the convex portion in the vicinity of the rear fender portion 30 in the side outer panel 12 It can be molded without causing wrinkles.

Further, the arc portions 44a and 44b of the first and second openings 36 and 38 in the second blank hole 34 where cracks are likely to occur during molding are close in diameter to the shape of the molded arc portion 46 after molding. By setting in advance so as to be, it is possible to suppress the inflow amount of the blank material 14 to the outside in the radial direction at the time of molding, and accordingly, by suppressing the deformation amount (elongation amount) after molding, the crack is formed. Can be suitably prevented.

Further, even when the arcuate portions 44a and 44b are expanded outward in the radial direction as described above, the arcuate portions 44a and 44b are upper-molded by the second blank holder 54 provided on the outer peripheral side of the first blank holder 52. By securely sandwiching it with the 50, the tension applied outward in the radial direction can be suitably adjusted without providing a bead.

In other words, even if the diameter of the arcuate portions 44a and 44b in the first and second openings 36 and 38 is increased in the second blank hole 34 to be on the outer peripheral side of the first blank holder 52. The second blank holder 54 can be securely sandwiched and molded.

That is, when the blank material 14 is drawn and formed in the press forming apparatus 10, the tension adjusting unit having the bead 74 applies the tension applied to the outside of the straight portions 40a and 40b of the second blank hole 34, respectively. The arc portion 44a is appropriately adjusted by 42a and 42b, and the arc portion 44a and 44b are shaped to be closer to the radial direction with respect to the molded arc portion 46 after molding to prevent the occurrence of cracks. , 44b, the tension to the outside can be adjusted by sandwiching it with the second blank holder 54.

As a result, even when deep drawing is performed on the blank material 14 having an opening, even if the inflow amount of the blank material 14 is large, cracks are unlikely to occur, but wrinkles are likely to occur in the straight portion 40a. The tension adjustment of 40b and the tension adjustment of the arcuate portions 44a and 44b in the first and second openings 36 and 38 having an arcuate cross section that is easily stretched and cracks are likely to occur when the inflow amount is large are preferably compatible with each other. Even when deep drawing is performed, for example, the second door opening 28 does not cause a crack in the second blank hole 34 of the blank material 14 having the arc portions 44a and 44b and the straight portions 40a and 40b. It is possible to obtain a side outer panel 12 (molded product) for an automobile, which requires a deep drawing shape in the width direction of the vehicle from the rear fender portion 30 to the rear fender portion 30.

It should be noted that the blank material according to the present invention, the press molding method for the blank material, and the press molding apparatus are not limited to the above-described embodiments, and of course, various configurations can be adopted without departing from the gist of the present invention. Is.

Claims (7)

A blank material that is drawn by a press forming device and becomes a body panel of an automobile.
An opening consisting of an arc portion provided in the vertical direction of the body panel and a substantially linear connecting portion provided in the front-rear direction of the body panel substantially orthogonal to the arc portion and connected to the arc portion. Have and
The blank material is provided with a tension adjusting portion extending toward the inside of the opening and adjusting the tension applied to the outside during molding. In the blank material according to claim 1,
The tension adjusting portion is a blank material formed for each of the set of the connecting portions. In the blank material according to claim 1 or 2,
The arc portion is a blank material formed in a shape that is small and close to the molded arc portion of the molded body in which the arc portion is molded. A press forming method for drawing and forming a blank material having an opening including an arc portion and a substantially linear connecting portion connected to the arc portion.
The peripheral edge of the opening is pressed and sandwiched by the first blank holder provided in the lower mold and the upper mold.
The arc portion that is outside the holding portion of the blank material sandwiched between the first blank holder and the upper mold is formed by the second blank holder and the upper mold provided outside the first blank holder. Press molding in which a tension adjusting portion extending from the connection portion toward the inside of the opening is sandwiched between the upper mold and the first blank holder to form a bead. Method. A press forming apparatus for drawing and forming a blank material having an opening including an arc portion and a substantially linear connecting portion connected to the arc portion.
With the upper mold
A lower mold arranged so as to face the upper mold and having a mounting surface on which the blank material is placed, and a lower mold.
A first blank holder that is arranged to face the upper mold and sandwiches the peripheral edge of the opening in the blank material together with the upper mold.
A second arc portion arranged outside the first blank holder and outside the sandwiching portion of the blank material sandwiched between the first blank holder and the upper mold is sandwiched between the upper mold and the arc portion. 2 blank holders and
Equipped with
The first blank holder and the upper mold are provided with a bead that pressurizes and sandwiches a tension adjusting portion extending inward from the connecting portion of the blank material. In the press molding apparatus according to claim 5 ,
The second blank holder is a press molding apparatus formed in an annular shape. In the press molding apparatus according to claim 5 or 6 .
The bead is a press forming apparatus extending along a direction substantially orthogonal to the extending direction of the tension adjusting portion.

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