JPH08267154A - Press die device - Google Patents

Abstract

PURPOSE: To prevent the occurrence of wrinkles as much as possible even in the case of being applied to a press machine low in loading capacity. CONSTITUTION: A 1st step part 13a and a 2nd step part 13b whose projecting heights are gradually decreased toward the side are provided on the top part of a bead 13, the inside of a bead housing part 23 is provided with a 1st step like recessing part 23a and a 2nd step like recessing part 23b being corresponding to these step parts 13a, 13b, and when a blank material is clamped between both, the projecting and recessing parts corresponding to the 1st step part 13a and the 2nd step part 13b are formed on the edge parts of the blank material.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bead for forming a bead in a portion corresponding to an edge of a blank material in one die and accommodating the bead in a portion facing the bead in the other die. The present invention relates to an improvement of a pressing die device in which a housing portion is formed and the bead and the edge portion of the blank material are sandwiched between the bead housing portions and the blank material is squeezed and stretched.

[0002]

2. Description of the Related Art Conventionally, a press die apparatus for applying a press machine to draw and project a blank material has been
In order to prevent wrinkles from occurring in the press-formed product,
As shown in (a), a bead 2 is formed on a portion of the upper die 1 corresponding to the edge of the blank material B, specifically, on the lower surface of the blank holder 1a, and the bead 2 is opposed to the bead 2 on the lower die 3. A bead accommodating portion 4 is formed in a portion, and the blank material B is subjected to drawing and overhanging processing while the edge portion of the blank material B is sandwiched between the bead 2 and the bead accommodating portion 4. There is.

According to such a pressing die device, as shown in FIGS. 5 (b) and 5 (c), the bead 2 is used.
When the blank material B is sandwiched between the bead accommodating portions 4, the unevenness 5 corresponding to the beads 2 is formed at the edge of the blank material B, and the punch 1b of the upper die 1 and the lower die 3 are formed.
When the blank material B is subjected to drawing / bulging processing by the molding concave portion 3a, the unevenness 5 becomes a resistance and the blank material B
Since it is possible to limit the amount of the resin that flows into the molding recess 3a, it is possible to prevent wrinkles from occurring in the press-molded product.

[0004]

By the way, in this type of pressing die device, the recess 3 for forming the blank B is formed.
When it is necessary to further limit the amount of inflow to a, that is, when the wrinkle suppressing force when the blank material B is subjected to the drawing / bulging processing by the punch 1b and the forming recess 3a is increased, normally, FIG. As shown in the drawing, a plurality of the beads 2 and the bead accommodating portions 4 are arranged in parallel, and the number of times of bending / bending / extending at the time of inflow of the blank material B into the molding recess 3a is increased so as to deal with this. ing.

However, in the pressing die apparatus as described above, when the unevenness 5a, 5b is formed at the edge of the blank B by the beads 2a, 2b and the bead accommodating portions 4a, 4b arranged in parallel, As shown in FIG. 7, an extremely large load is required as compared with the case where the single bead 2 and the bead accommodating portion 4 are provided. That is, as shown in FIG. 6, between the bead 2b and the bead accommodating portion 4b arranged on the outer edge portion side (the right side in the figure) of the blank material B, the blank material B sufficiently flows in from the outer edge portion which is free. However, although the unevenness 5b can be formed mainly by bending with a relatively small forming load, the bead 2b and the bead 2b and the bead 2b arranged outside are arranged between the bead 2a and the bead accommodating portion 4a arranged inside. This is because the inflow of the blank material B is restricted by the housing portion 4b and both sides are suppressed, that is, the unevenness 5b is formed in a state close to the drawing process that requires a relatively large forming load (FIG. 8). ).

Therefore, when the blank material B is subjected to drawing and overhanging processing by applying a press machine having a low load capacity, desired unevenness 5a, 5b can be formed on the edge portion of the blank material B. Therefore, it may be difficult to prevent the press-formed product from wrinkling.

In view of the above situation, an object of the present invention is to provide a press die device capable of preventing the occurrence of wrinkles even when applied to a press machine having a low load capacity. It is in.

[0008]

According to the present invention, a bead is formed in a portion of one die corresponding to an edge of a blank material, and the bead is housed in a portion of the other die opposite to the bead. To form a bead housing,
In a die unit for a press adapted to perform drawing and overhanging processing on the blank material while sandwiching the edge portion of the blank material between the beads and the bead accommodating portion, individual protrusion heights at the tip end portion of the bead Is provided with a step portion of a mode that gradually decreases toward the side, and a step-like recessed portion corresponding to the step portion is provided inside the bead accommodating portion, and when a blank material is sandwiched between them, Concavities and convexities corresponding to the stepped portions are formed on the edge portion.

It is preferable that each of the step portions has a flat portion at a portion facing the other mold.
Further, it is preferable that the protruding height gradually decreases toward the edge of the blank material.

[0010]

According to the above-described structure, the blank material is sequentially brought into contact with the blank material from the step portion having a high protruding height to form the unevenness on the edge portion of the blank material.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings showing an embodiment. FIG. 1 conceptually shows a main part of a press die device according to the present invention. The die device illustrated here is a single-acting press machine for drawing (not shown).
The present invention is applied to the case where body parts such as a roof panel and a fender panel of a four-wheeled vehicle are press-molded by the single-acting press machine. The bead 13 is provided at a portion of the peripheral wrinkle suppressing surface 12 corresponding to the edge of the blank B, and the portion of the lower die 20 facing the bead 13, specifically, the periphery of the punch 21. The bead accommodating portion 23 is provided on the upper surface of the blank holder 22 configured as described above.

The bead 13 is, as shown in FIG.
0 is provided all over the periphery of the molding recess 11 and, as shown in FIG. 1, has a first step portion 13a and a second step portion 13b having different projecting heights in the cross section thereof. There is. The first step portion 13a has a rectangular cross section, and its tip portion is flat in a manner that it is orthogonal to the opening / closing direction of the mold (vertical direction in the drawing).
The upper mold 10 is arranged laterally close to the molding recess 11. The second step portion 13b has a rectangular cross-section whose protrusion height and width are approximately half of the first step portion 13a, and its tip portion is similar to the first step portion 13a. Has a flat shape in a manner orthogonal to the opening / closing direction of the mold. As is clear from the figure, the bead 13 is formed integrally with the upper mold 10, and the first sloped surface 1 on both sides of the second step portion 13b is smooth.
3c and the second inclined surface 13d allow the first step portion 13 to be formed.
a and the wrinkle suppressing surface 12 of the upper mold 10, and the individual corners are rounded by chamfering.

On the other hand, the bead accommodating portion 23 has the bead 1
The first step-shaped recess 23 is provided in a portion facing the first step 13a of
In addition to having a, the second stepped portion 23b is provided at a portion facing the second stepped portion 13b. First stepped recess 2
3a has a substantially rectangular cross section, and its bottom surface is flat so as to be orthogonal to the opening and closing direction of the mold, and has a depth deeper than the projecting height of the first step portion 13a. More specifically, it has a depth almost twice as large as that of the first step portion 13a, and the first step portion 13a and the first inclined surface 13c.
Is formed to have a width to accommodate the. Second stepped recess 23b
Has a depth substantially equal to the protruding height of the second stepped portion 13b, the bottom surface of which is formed flat so as to be orthogonal to the opening / closing direction of the mold, and the second inclined surface 13d has The facing portion constitutes a third inclined surface 23c having the same inclination angle as the second inclined surface 13d. As is clear from the figure, also in this bead housing portion 23, each corner portion is rounded by chamfering.

In the mold apparatus constructed as described above, when the above-mentioned single-acting press machine (not shown) is driven with the blank material B interposed between the upper mold 10 and the lower mold 20, first, The bead 13 provided on the wrinkle suppressing surface 12 of the upper mold 10 by sandwiching the edge of the blank material B between the wrinkle suppressing surface 12 of the upper mold 10 and the blank holder 22 of the lower mold 20.
And the bead accommodating portion 23 provided on the blank holder 22 of the lower die 20 makes the unevenness B on the entire circumference of the edge portion of the blank material B.
P is formed.

At this time, the bead 13 is used in the mold apparatus.
The first step portion 13a and the second step portion 13b of FIG.
As shown in (e) to FIG. 2 (g), after the first step portion 13a having a high protruding height abuts on the blank B and deforms it, the second step portion 13b having a low protruding height is It comes into contact with the blank B and deforms it, and the bead 1
Since the tip portions of the respective step portions 13a and 13b of No. 3 are configured to be flat, as shown in FIG. 2 (e), the first step portion 13a
Even after the blank material B has been deformed by
The flexure BT of the blank B remains at the portion corresponding to the tip of the first step portion 13a.

Therefore, any protrusion 1 of the bead 13
Even when deformed by 3a and 13b, the blank material B sufficiently flows in from the outer edge portion that becomes free, or the flexure BT remaining at the tip portion of the first step portion 13a that has been previously deformed,
Asperity B mainly due to bending with relatively small load
P will be formed.

The first step portion 13 of the bead 13 described above is also used.
Since a difference in protrusion height between a and the second step portion 13b causes a time lag during deformation, and the amount of deformation of the blank material B gradually decreases as the deformation progresses.
The load itself for forming P is also reduced.

These phenomena are not limited to the simulation results by the finite element method shown in FIG.
It is also clear from the experimental results shown in (b).

Therefore, according to the mold apparatus, even when a press machine having a low load capacity is applied, a desired unevenness BP, that is, the bead 13 is formed on the edge of the blank B.
Since it becomes possible to reliably form the unevenness BP having the two step portions BP1 and BP2 corresponding to the first step portion 13a and the second step portion 13b provided on the lower mold 2
When the blank material B is squeezed and stretched by the punch 21 of 0 and the molding recess 11 of the upper die 10, the blank material B is molded as compared with the case where the bead 13 and the bead accommodating portion 23 are provided alone. The number of times of bending / bending / extending at the time of inflow into the use recess 11 is increased, and it is possible to prevent the press-formed product from being wrinkled due to an increase in the wrinkle suppressing force.

Moreover, the bead 13 has the first step portion 13
a and the second step portion 13b are arranged as close to each other as possible, and the second step portion 13b has a lower protruding height than the first step portion 13a. A blank material B having a smaller area than that of a plurality of materials arranged in parallel can be applied, which is also advantageous in terms of yield.

In the above-mentioned embodiment, the die device applied to the single-acting press machine and for molding the body parts of the four-wheeled vehicle is illustrated, but a double-acting press machine, a three-action press machine, etc. Of course, it can be applied to a press machine, and of course, it may be a press-molded product other than a body part of a four-wheeled vehicle.

In the above embodiment, the upper mold is provided with the bead and the lower mold is provided with the bead accommodating portion. However, these beads and the bead accommodating portion may be provided in the opposite manner. The formation positions of these beads and bead accommodating portions are determined by the molding conditions such as the molding direction and the molding depth resulting from the shape of the press-molded product. It does not need to be provided all around.

Further, in the above-mentioned embodiment, the mold apparatus in which the bead is provided with two step portions is illustrated, but if the protrusion height is gradually reduced to the side, three or more step portions are provided. A bead provided with a part may be applied. In this case, although it is preferable that the projecting height of each step is arranged so as to gradually decrease only toward the edge of the blank material, according to the present invention, the projecting height toward the inner side of the blank material is increased. Even when the step portion is provided in a manner in which the step is gradually reduced, the amount of deformation of the blank material due to each step portion when forming the unevenness is gradually reduced, and the tip of each step portion is configured to be flat. In addition, since the bending of the blank material remains at the tip of the step that has been previously deformed, when unevenness is formed as compared to the case where a plurality of beads and bead accommodating portions of the same shape are arranged in parallel as before. It is possible to reduce the load.

[0024]

As described above, according to the present invention,
Since the blank material is sequentially contacted and deformed from the step portion having a high protruding height, the desired unevenness can be surely formed even when applied to a press machine having a low load capacity, and a wrinkle is formed on the press-formed product. It is possible to prevent the situation that occurs as much as possible.

Moreover, since the steps are arranged as close to each other as possible and the projecting heights of the steps are gradually reduced, as compared with the conventional method, a plurality of beads having the same shape are arranged in parallel. A blank material having a small area can be applied, which is advantageous in terms of yield.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view conceptually showing a main part of a pressing die device according to the present invention.

FIG. 2 is a cross-sectional view of an essential part conceptually showing a forming process of a blank material to which the apparatus of the embodiment shown in FIG. 1 is applied.

FIG. 3 is a perspective view conceptually showing one mold applied to the apparatus of the embodiment shown in FIG.

4A and 4B show a relationship between a stroke amount and a load in the embodiment apparatus shown in FIG. 1, where FIG. 4A is a diagram showing a simulation result by a finite element method, and FIG. 4B is a diagram showing an experimental result. is there.

FIG. 5 is a sectional view conceptually showing a forming process of a blank material to which a conventional pressing die device is applied.

FIG. 6 is a cross-sectional view of an essential part conceptually showing the forming process of a blank material to which a conventional pressing die device is applied.

FIG. 7 is a table showing a relationship between a stroke amount and a load depending on the number of beads in a conventional pressing die device.

FIG. 8 is a chart showing a relationship between a stroke amount and a load depending on a bead arrangement position in a conventional pressing die device.

[Explanation of symbols]

 10, 20 ... Mold 13 ... Bead 13a, 13b ... Step portion 23 ... Bead accommodation portion 23a, 23b ... Step concave portion B ... Blank material BP ... Concavity and convexity

Front page continuation (72) Inventor Ryozo Mizuno 300 Takatsukacho, Hamamatsu City, Shizuoka Prefecture Suzuki Stock Company

Claims (3)

[Claims] 1. A bead accommodating portion for accommodating the bead is formed in a portion of one die corresponding to an edge of a blank material, and a bead accommodating portion for accommodating the bead in a portion of the other die opposed to the bead. In a die unit for a press adapted to perform a drawing / expansion process on the blank material while sandwiching an edge portion of the blank material between the beads and the bead accommodating portion, the protrusion height of each of the beads at the tip end portion is increased. Is provided with a step portion of a mode that gradually decreases toward the side, and a step-like recessed portion corresponding to the step portion is provided inside the bead accommodating portion, and when a blank material is sandwiched between them, A press die device, characterized in that irregularities corresponding to the stepped portions are formed on an edge portion. 2. The press die device according to claim 1, wherein the stepped portion is configured such that a portion facing the other die is flat. 3. The press die apparatus according to claim 1, wherein the stepped portion has a projecting height that gradually decreases toward an edge of the blank material.