JP5444687B2 - Die for press molding, press molding method, and hat-shaped molded product - Google Patents

Description

  The present invention relates to a press forming technique for forming a plate-like workpiece into a hat-shaped molded product having a container part main body having a side wall part and a flange part continuous to the container part main body, and its The present invention relates to a molded product formed by molding.

  In recent years, in order to reduce the weight of automobile vehicles, press molded products such as member members and cross members in vehicles tend to have higher strength materials. However, increasing the strength of the material will cause a larger spring back that causes molding defects. Such a springback is caused by residual stress (stress difference between the inside and outside of the plate thickness) caused by bending and unbending at the die R of the mold during molding (drawing and bending). As the strength increases, it becomes more prominent.

As countermeasures against such problems, conventionally, the mold shape was designed in anticipation of the occurrence of springback, or much time was spent tuning the mold to suppress the occurrence of springback. . However, such a measure takes time and labor to manufacture the mold.
As a technique for such a problem, for example, there is a technique described in Patent Document 1. This prior art device applies a compressive force that applies a compressive force in the direction of easy buckling in a molded product, in which the spring back is generated by press-molding the hat shape once. Device.

  Specifically, a compression means for applying a compressive force to a predetermined portion of the molded product by a pair of molds, and a seat that is in close contact with the molded product through before and after compression to prevent buckling. Bending prevention means is provided. The buckling prevention means is constituted by a side wall forming surface composed of a plurality of members that can move relative to each other in the direction in which the compressive force is applied. Although it is possible, the cavity shape that corrects the molded product to the ideal shape is configured by providing the coupling portions that alternately mesh so that the movement in the direction orthogonal to the clamping direction is restricted. 1 and a second mold clamping state for applying a compressive force to the molded product.

  And since the compression means which provides compression force to the predetermined part of a molded product is comprised by a pair of metal mold | die, compression force can be provided to the said molded product by mold clamping. In addition, the buckling prevention means is constituted by a side wall portion molding surface composed of a plurality of members that can move relative to each other in the direction in which the compressive force is applied, and the plurality of members move relative to each other in the mold clamping direction. It is possible, however, to provide a cavity shape that corrects the molded product to the ideal shape by providing alternately meshing connection parts so that the movement in the direction orthogonal to the clamping direction is restricted. Since the first mold-clamping state and the second mold-clamping state for applying a compressive force to the molded product, the side wall portion molding surface is in close contact with the molded product continuously before and after compression. The compression force can be applied to a predetermined portion of the molded product while preventing buckling of the molded product.

In addition, as mentioned above, this technique assumes that a residual stress removing step for applying a compressive force without causing buckling is provided for a plate material in which a springback or the like is generated after forming a molded product. It is what. As a result, it is not necessary to anticipate the occurrence of a springback or the like at the time of mold manufacture, and the mold can be tuned in a short time, and the mold can be easily manufactured.
Japanese Patent No. 3856094 Japanese Patent No. 3772965

  In the above prior art, the side wall of the molded product is warped before compression is applied, and the warp is corrected by in-plane compression. However, in order to correct the warp once generated, it is necessary to apply a large compressive force. If a large compressive force is applied, buckling may occur, and the shape improvement effect is reduced accordingly. In addition, a mold for correcting a molded product is complicated.

Although there is a technique described in Patent Document 2, in this technique, the spring back is suppressed by pulling, and there is a possibility that cracking may occur due to pulling bending when pulling strongly.
The present invention pays attention to the above-mentioned points, and does not complicate the mold, and can greatly reduce the occurrence of springback, a press mold, a press molding method, and a hat mold shape. The issue is to provide molded products.

In order to solve the above-mentioned problems, the invention described in claim 1 of the present invention is characterized in that a flat plate-shaped workpiece is formed from a bottomed container-shaped container body having a side wall and a flange continuous to the container body. A mold for press molding for molding into a hat-shaped molded product comprising a portion,
A female mold, a punch that is relatively inserted into the recess of the female mold to form the container body, and a blank holder that is disposed on the outer periphery of the punch and that is opposed to the press surface formed on the outer side of the recess of the female mold. With
The blank holder is characterized in that a constraining portion is formed in which the end surface of the outer peripheral portion of the work piece comes into contact with the blank holder and the movement of the end surface to the outside is constrained.

Furthermore, the invention described in claim 1, compared upper Symbol punch, which is characterized in that a projecting portion facing the recess the outer edge of the female upon inserting the punch into the recess of the female It is.
Next, in the invention described in claim 2 , with respect to the configuration described in claim 1, the clearance between the inner surface of the concave portion of the female mold and the punch when the molding is completed is set wider than the plate thickness of the workpiece. It is characterized by doing.

Next, the invention described in claim 3 is a hat-shaped workpiece having a plate-shaped workpiece including a bottomed container-like container body having a side wall and a flange continuous with the container body. A mold for press molding for molding into a molded product, a female mold, a punch that is relatively inserted into a recess of the female mold to mold the container body, and a female disposed on the outer periphery of the punch. A blank holder facing the pressing surface formed on the outer side of the concave portion of the mold, and the outer peripheral end surface of the workpiece contacts the blank holder in the middle of molding to restrain the movement of the end surface to the outside. A press molding method using a press molding die in which a restraint portion is formed,
From the state in which the flat plate-shaped workpiece is disposed between the female mold and the punch, the punch is relatively placed in the female mold recess, and a gap is left where the compressive force can be transmitted from the flange side to the container body side. And insert it to a position before the molding completion position, and temporarily mold it into the shape of the container body,
Next, the blank holder is relatively moved closer to the female mold, the outer peripheral end surface of the workpiece is brought into contact with the blank holder, and the blank holder is further moved closer to the female mold, The outer peripheral end face is restrained by the restraining part,

Next, the compression force is applied from the outer peripheral end face of the workpiece to the container body side by relatively inserting the punch further into the recess of the female mold and relatively bringing the blank holder closer to the female mold. The container body is formed into a final shape while forming the flange portion in a state where is provided.
If there is a gap that can transmit the in-plane compressive force to the position before the molding completion position so that a gap that allows the in-plane compressive force to be transmitted from the flange side to the container body side remains. good. For example, the position before the molding completion position may be set within a range of 1 mm or less.
Next, the invention described in claim 4 is the same as that described in claim 3, except that when the punch is inserted into the recess of the female mold, the female mold is inserted into the press mold. An overhanging portion facing the outer edge of the recess is provided.
Next, the invention described in claim 5 provides a hat-shaped molded product formed by the press molding method according to claim 3 or claim 4 .

If the metal mold | die of the invention of Claim 1 is used, generation | occurrence | production of a spring back will be suppressed significantly, and it will become possible to shape | mold into a hat-shaped shape with sufficient dimensional accuracy, without complicating a metal mold | die.
Further, according to the invention described in claim 1, it is possible to restrain more reliably restrained portion of the end surface of the outer peripheral edge of the workpiece.

According to the second aspect of the present invention, by making the clearance at the time of final molding wider than the thickness of the workpiece, it becomes easy to transmit the compressive force in the in-plane direction to the container body. As a result, the shape accuracy is improved .

As a result, it is possible to significantly reduce the occurrence of springback without complicating the mold and to form a hat-shaped shape with good dimensional accuracy.
In addition, the invention according to claim 4 makes it possible to suppress the input of bending and unbending to the side wall when molding the container body, thereby reducing the occurrence of warping of the side wall. Moreover, the residual stress can be removed by applying an in-plane compressive force at the time of forming the flange portion. Moreover, it becomes easier to propagate the in-plane compression force to the container body.
That is, the invention described in claim 4 is effective when the in-plane compression force is difficult to propagate to the container body due to a small mold clearance or a small die R.

(First embodiment)
Next, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing a hat-shaped molded product according to the present embodiment. FIG. 2 is a schematic diagram showing the mold structure of the present embodiment.
Here, in this embodiment, the flat plate-like workpiece F0 is continuously connected to the container-shaped main body 1 with the bottom 1b having the side wall 1a and the container main body 1 as shown in FIG. This is an example in which a molded product F is manufactured by press-molding into a hat-shaped shape provided with a flange portion 2 projecting to the outer periphery. In addition, the side wall part 1a does not need to be flat and a level | step difference etc. may be formed in the middle.

(Mold structure)
The metal mold | die used for the press molding of this embodiment is provided with the female die 3 (die | dye) which comprises an upper mold | type, the punch 4 and the blank holder 5 which comprise a lower mold | type, as shown in FIG.
The female mold 3 and the blank holder 5 can be moved up and down separately by being driven by individual actuators.

The female mold 3 is formed with a recess 3A having the same shape as the container body 1. In addition, the lower surface, which is the outer peripheral surface continuous with the recess 3 </ b> A, in the female die 3 serves as the upper pressing surface 3 </ b> B that presses the flange portion 2. The outer edge 3a (die R portion) of the recess 3A, which is the boundary between the recess 3A and the upper pressing surface 3B, is provided with a convex radius (curvature).
The upper pressing surface 3B is divided into an upper pressing surface main body 3Ba and an upper pressing outer peripheral surface 3Bb on the outer peripheral side thereof. The upper presser surface main body 3Ba is a surface with which a portion to be the flange portion 2 of the workpiece F0 comes into contact. A step is formed between the upper presser surface main body 3Ba and the upper presser outer peripheral surface 3Bb, and the upper presser outer peripheral surface 3Bb is offset upward with respect to the upper presser surface main body 3Ba.

The punch 4 is disposed so as to be coaxial with the concave portion 3A of the female die 3 and can be moved up and down. The punch 4 includes a punch main body 4A and a pillar portion 4B continuous with the punch main body 4A. The punch body 4 </ b> A has the same outer shape as the container body 1, and the workpiece F <b> 0 is formed into the shape of the container body 1 by being inserted into the recess 3 </ b> A of the female mold 3.
Further, the size of the column 4B is larger than that of the lower end of the punch body 4A, and an overhang 4C is formed at the boundary between the punch body 4A and the column 4B. On the upper surface of the overhanging portion 4C, when the punch body 4A is inserted into the concave portion 3A of the female die 3 and formed, a concave radius that is opposite to the radius formed on the outer edge portion of the concave portion 3A is formed. It has the role of bending the plate material portion extending outward from the recess 3A so as to spread outward during molding.

  The blank holder 5 is disposed on the outer periphery of the punch body 4A, and the upper surface of the blank holder 5 is opposed to the upper pressing surface 3B of the female mold 3 from below. The upper surface of the blank holder 5 forms a lower pressing surface 5A. The lower presser surface 5A includes a lower presser surface main body 5Aa facing the upper presser surface main body 3Ba, and a lower presser outer peripheral surface 5Ab on the outer peripheral side thereof. A step is formed at the boundary between the lower presser surface main body 5Aa and the lower presser outer peripheral surface 5Ab on the outer periphery, and the lower presser outer peripheral surface 5Ab is offset upward with respect to the lower presser surface main body 5Aa. . The height of the step is equal to or greater than the thickness of the workpiece F0. The step becomes the restraining portion 6.

(Press molding method)
FIG. 3 is a diagram for explaining the process.
Here, in this embodiment, the punch 4 and the blank holder 5 are set so as to be able to be moved up and down, and can be moved up and down individually. Further, it is assumed that the molding is completed by lowering the female die 3 to the bottom dead center and raising the blank holder 5 to the top dead center. Further, the clearance c between the female die 3 and the punch 4 at the time of completion of molding is set as in the following equation, for example, in relation to the plate thickness t of the workpiece F0. However, (c / t) may be set larger than 1.1. (C / t) may be set depending on the final forming accuracy.
1 ≦ (c / t) ≦ 1.1

First, as shown in FIG. 3A, a flat plate-like workpiece F <b> 0 is disposed between the female die 3 and the punch 4.
Here, the plate width of the workpiece F0 is set to be longer than the cross-sectional line length of the molded product. The difference between the plate width of the workpiece F0 and the cross-section line length of the molded product is preferably 5% or less of the cross-section line length of the molded product. This is because if it exceeds 5%, the flange portion 2 is likely to buckle. But if it is a molded article in which buckling may occur in the flange portion 2 and wrinkles may be formed, it may be set to exceed 5%.

Next, as shown in FIG. 3B, the container part main body 1 is molded by lowering the female mold 3 to the bottom dead center and relatively inserting the punch 4 into the recess 3A. In addition, the structure which raises the punch 4 side may be sufficient.
In consideration of the fact that the outer peripheral portion of the workpiece F0 faces downward during the molding process of the container body 1, the blank holder 5 is lowered to a position where the workpiece F0 does not contact the upper surface of the blank holder 5. Keep away from the incoming female mold 3.

  Further, as described above, when the punch 4 is relatively inserted into the recess 3A and the container body 1 is formed, the outer edge portion (die) of the recess 3A is lowered in the later stage when the female mold 3 is lowered to the bottom dead center. R) and the protruding portion 4C of the punch 4 and the bending is input to the boundary portion between the container portion main body and the flange portion 2 in the workpiece F0. As a result, the outer peripheral portion of the workpiece F0 is oriented in the direction of spreading outward.

Next, the blank holder 5 is raised to bring the blank holder 5 close to the female mold 3. At this time, the outer peripheral end face 10 of the workpiece F0 is in contact with the lower presser surface main body 5Aa in the middle of ascending, and as it further rises, it moves outward along the lower presser surface main body 5Aa. ), The contact with the step forming the restraining portion 6 is restricted, and further outward movement is restricted.
In this state, the blank holder 5 is further raised to FIG. At this time, since the outer peripheral end face 10 is in a state of being restrained by the restraining portion 6, bending is performed in a state where in-plane compression is applied.

(Operational effect of this embodiment)
Here, FIG. 4 shows an example of a drawing process generally performed. As shown in this figure, in normal drawing, the outer peripheral portion (flange portion) of the workpiece is held by the blank holder, and then the punch is relatively inserted into the female die for drawing.
For this reason, the part which becomes a side wall part of a container part main body is bent in the middle of shaping | molding, and receives bending back. By this bending and bending back, the side wall of the container body is warped.

Moreover, the example of the process of the die bending shaping | molding currently generally performed is shown in FIG. As shown in this figure, in normal mold bending, the container body 1 and the flange are simultaneously bent using the lower mold in which the punch and the blank holder are integrated.
In this case, at a later stage of molding, the end of the workpiece is bent so as to bend in contact with the lower mold, so that the portion that becomes the side wall of the container body is also bent and unbent. Thus, the side wall of the container body is warped.

On the other hand, in the molding method of the above embodiment, when the container 4 is molded by inserting the punch 4 into the recess 3A of the female mold 3, the outer peripheral portion of the workpiece F0 is released. No bending or unbending during molding or small.
Subsequently, when forming the flange portion 2 to be applied, bending is performed in a state where the outer peripheral end portion of the workpiece F0 is constrained by the constraining portion 6. That is, by applying an in-plane compressive force at the final stage of molding, the shape of the molded product F can be improved without causing cracks.

In the above-described conventional example, since a compressive force is applied to the warp once generated, a large compressive force is required. In this embodiment, an in-plane compressive force is applied in a state where the warp is small. Therefore, the in-plane compressive force applied for removing the residual stress is smaller than that of the above-described conventional example, and the residual stress can be removed during molding.
Further, in the present embodiment, it is not necessary to process the mold in anticipation of the spring back, and the mold configuration itself does not need to be complicated.

Further, if the clearance c between the female die 3 and the punch 4 in the finished molding state is made larger than the plate thickness t of the workpiece F0, the in-plane compression force to the container body 1 is more easily transmitted. , Shape accuracy is improved.
Here, in the middle of molding, in order to restrain the outer peripheral end face 10 of the workpiece F0 by the restraining portion 6, as described above, the plate width of the workpiece F0 is made longer than the cross-sectional line length of the molded product. Set to. At this time, if the difference between the plate width of the workpiece F0 and the cross-sectional line length of the molded product is large, wrinkles (buckling) may be formed in the molded flange portion 2, but the above-described effects are obtained. It is possible to obtain.

(Modification)
(1) In the above-described embodiment, the case where the protruding portion 4C is provided with respect to the punch 4 is described as an example, but the present invention is not limited to this. As shown in FIG. 6, the punch 4 is not necessarily provided with the overhanging portion 4C.
In this case, when the container body is molded, the outer peripheral side of the work material F0 is not bent outward, but by the rise of the blank holder 5, which is the subsequent process of molding the flange 2 There is no problem as long as the outer peripheral end of the workpiece F0 comes into contact with the lower pressing surface main body 5Aa of the blank holder 5 and moves outward along the lower pressing surface 5A.

That is, if the side wall portion 1a of the container body to be molded is inclined so as to be separated from the bottom portion 1b, the outer peripheral end of the workpiece F0 is obliquely outward when the container body is molded. Extend. For this reason, when the outer peripheral end portion of the workpiece F0 comes into contact with the lower pressing surface main body 5Aa of the blank holder 5, a force is generated to move the outer peripheral end portion end face 10 of the workpiece F0 outward. . The protruding portion 4C is not necessarily required as long as it can be slid along the lower pressing surface main body 5Aa by the force to move outward.
However, it is possible to reliably bring the outer peripheral end portion of the workpiece F0 into contact with the restraint portion 6 by providing the overhang portion 4C and causing the bending.
(2) In the above embodiment, the case where the female mold 3 and the blank holder 5 are moved is described as an example. However, the above-described molding may be performed by appropriately moving the punch 4 side.

(Second Embodiment)
Next, a second embodiment will be described with reference to the drawings. Note that the above-described components and the like will be described with the same reference numerals.
The mold structure of the present embodiment is the same as that of the first embodiment.
However, the press molding process is slightly different.

(Press molding method)
FIG. 7 is a diagram for explaining the process.
First, as shown in FIG. 7A, a flat plate-shaped workpiece F <b> 0 is disposed between the female die 3 and the punch 4.
Here, the plate width of the workpiece F0 is set to be longer than the cross-sectional line length of the molded product.

  Next, as shown in FIG. 7B, the container part main body 1 is temporarily formed by lowering the female mold 3 to the vicinity of the bottom dead center. Note that the female mold 3 may be slightly raised after the female mold 3 is lowered to the bottom dead center. The vicinity of the bottom dead center is preferably set to a position 1 mm or less before the bottom dead center (molding completion position). By forming the gap slightly, an in-plane compression force described later is easily transmitted to the container body 1. That is, it is only necessary to provide the container body 1 with a gap as long as it can be easily transmitted from the position where the flange 2 is formed. Further, if lubricating oil is added between the workpiece F0 and the mold, the gap can be further reduced. Also in the first embodiment, lubricating oil may be added between the workpiece F0 and the mold.

At this time, the outer peripheral portion of the workpiece F0 is bent downward, but the blank holder 5 is separated from the descending female die 3 at a position where the workpiece F0 does not contact the blank holder 5.
At this time, the outer peripheral portion of the workpiece F0 is directed downward, but is slightly opened outward by the overhang portion 4C.

  Next, the blank holder 5 is raised to bring the blank holder 5 close to the female mold 3. At this time, the blank holder 5 is raised to the top dead center. That is, in the vicinity of the bottom dead center of the female mold 3, for example, when the blank holder 5 is raised, the female mold 3 is lowered until the outer peripheral end face of the workpiece F 0 comes into contact with the restraining section 6. It may be defined by making it close to the dead point.

Next, the female mold 3 is further lowered to the bottom dead center, whereby the final molding of the container body 1 and the bending molding of the flange 2 are performed. At this time, since the end portion of the workpiece F0 is constrained by the constraining portion 6, bending is performed in a state where an in-plane compression force is applied.
(Operational effect of this embodiment)
The effect of this embodiment is the same as that of the first embodiment.
That is, in the molding method of the second embodiment, when the container part body 1 is temporarily molded by inserting the punch 4 into the recess 3A of the female mold 3, the outer peripheral part of the workpiece F0 is released. No bending or unbending in the middle or small.

Subsequently, when forming the flange portion 2 to be applied, bending is performed in a state where the outer peripheral end portion of the workpiece F0 is constrained by the constraining portion 6. That is, by applying an in-plane compressive force at the final stage of molding, the shape of the molded product F can be improved without causing cracks.
At this time, the container part main body 1 is finally formed by stopping the female mold 3 just before the bottom dead center and applying the in-plane compression force by forming the flange part 2. It becomes easier to propagate the compressive force to the wall portion and the side wall portion 1a than in the first embodiment.
Other configurations / effects and modifications are the same as those in the first embodiment.

(Example)
Next, examples of molding using the mold structure shown in the first and second embodiments will be described.
As the workpiece F0, an alloyed hot-dip galvanized steel sheet having a tensile strength of 980 MPa and a thickness of 1.4 mm and a cold-rolled steel sheet having a tensile strength of 1180 MPa and a thickness of 1.2 mm were used.
As the mold, two types of punch 4 were used: a mold having the above-described overhanging portion 4C and a mold having no above-mentioned overhanging portion 4C. The mold provided with the overhang portion 4C is referred to as A type, and the mold not provided with the overhang portion 4C is referred to as B type. However, in the comparative example, no restraint is provided on the lower presser surface 5A.

Further, as the molding method, the molding method described in the first embodiment is referred to as type 1, and the molding method described in the second embodiment is referred to as type 2.
Further, the normal drawing and normal bending in the comparative example are the molding methods shown in FIGS. 4 and 5 described above. Moreover, what described the patent number shows having shape | molded with the patent technology.

Further, as shown in FIG. 8, the width of the molded product F after molding is referred to as W, and the warp of the side wall portion 1 a occurring in the molded product F is referred to as ρ. This warp ρ becomes a part of the springback. The warp ρ is measured with a span 25 mm curvature meter.
Further, as shown in FIG. 9, the die shoulder width Wd was set to 80 mm as a mold.
The experimental results are shown in Table 1 below.

Here, c is the clearance between the upper mold and the lower mold when the molding is completed, and t is the thickness of the workpiece F0 before molding.
Moreover, plate | board width ratio is represented by a following formula. In the present invention, the plate width ratio is a value larger than 1.
Sheet width ratio = (sheet width before molding) ÷ (section length of molded product)
ΔW is expressed by the following equation. A smaller ΔW indicates a smaller spring back.
ΔW = W−Wd
As can be seen from the above table, in all cases based on the present invention, ΔW is less than 1, and the occurrence of springback can be significantly suppressed as compared with the comparative example.

Even when considering the warp ρ of the side wall 1a, it can be reduced to 0.001 or less compared to the comparative example.
In addition, No. of the present invention example. When comparing 1 to 4, there is a tendency that the larger the plate width ratio is, the smaller ΔW is improved.
Here, Comparative Example No. 30 is performed under the same conditions as in the present embodiment except for restraint by the restraint unit 6. Although it is possible to suppress the spring back as compared with other comparative examples, the present invention example No. Compared with 1-6, it turns out that the direction of this invention can hold down a spring back smaller.

It is a figure explaining the molded article which concerns on embodiment based on this invention. It is a figure explaining the metal mold | die which concerns on embodiment based on this invention. It is a figure explaining the press molding method which concerns on 1st Embodiment based on this invention. It is a figure explaining the process of normal drawing. It is a figure explaining the process of normal mold bending. It is a figure explaining the other example of the metal mold | die which concerns on embodiment based on this invention. It is a figure explaining the press molding method which concerns on 2nd Embodiment based on this invention. It is a figure explaining the molded article in an Example. It is a figure explaining the metal mold | die in an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Container part main body 1a Side wall part 1b Bottom part 2 Flange part 3 Female type | mold 3A Recessed part 3B Upper pressing surface 3Ba Upper pressing surface main body 3Bb Upper pressing outer peripheral surface 3a Outer edge part 4 Punch 4A Punch main body 4B Column part 4C Overhang part 5 Blank holder 5A Lower presser surface 5Aa Lower presser surface body 5Ab Lower presser outer peripheral surface 6 Restraint portion 10 Outer peripheral end surface F Molded product F0 Work material t Thickness c Clearance

Claims (5)

Press molding die for forming a plate-like workpiece into a hat-shaped molded product having a bottomed container-like container body having a side wall and a flange continuous with the container body. Because
A female mold, a punch that is relatively inserted into the recess of the female mold to form the container body, and a blank holder that is disposed on the outer periphery of the punch and that is opposed to the press surface formed on the outer side of the recess of the female mold. With
With respect to the blank holder, the outer peripheral end surface of the work piece abuts in the middle of molding to form a restraining portion that restrains the movement of the end surface to the outside, and the punch is inserted into the female concave portion with respect to the punch. A press-molding die having a protruding portion facing the outer edge of the female recess.   2. The press-molding die according to claim 1, wherein a clearance between the inner surface of the concave portion of the female die and the punch when the molding is completed is set wider than the plate thickness of the workpiece. Press molding die for forming a plate-like workpiece into a hat-shaped molded product having a bottomed container-like container body having a side wall and a flange continuous with the container body. A female mold, a punch that is relatively inserted into the recess of the female mold to form the container body, and a pressing surface that is disposed on the outer periphery of the punch and is formed outside the recess of the female mold. A blank holder, and a press-molding die having a restraint portion that restrains movement of the outer peripheral portion of the workpiece to the outside by contacting the blank holder in the middle of molding with respect to the blank holder. Press forming method,
From the state in which the flat plate-shaped workpiece is disposed between the female mold and the punch, the punch is relatively placed in the female mold recess, and a gap is left where the compressive force can be transmitted from the flange side to the container body side. And insert it to a position before the molding completion position, and temporarily mold it into the shape of the container body,
Next, the blank holder is relatively moved closer to the female mold, the outer peripheral end surface of the workpiece is brought into contact with the blank holder, and the blank holder is further moved closer to the female mold, The outer peripheral end face is restrained by the restraining part,
Next, the compression force is applied from the outer peripheral end face of the workpiece to the container body side by relatively inserting the punch further into the recess of the female mold and relatively bringing the blank holder closer to the female mold. A press molding method, wherein the container body is molded into a final shape while the flange portion is being molded in a state where the above is applied. To the press molding die, according to claim 3, characterized in that to the punch, and upon inserting the punch into the recess of the female mold provided with a projecting portion facing the recess the outer edge of the female mold Press forming method. A hat-shaped molded product, which is molded by the press molding method according to claim 3 or 4 .

Images