JPH0751757A - Press forming device and method therefor - Google Patents

Abstract

PURPOSE:To prevent a formed product from being occurred in wrinkle and surface strain and a material from being affected with work effect without adopting a complex structure and method when forming a three-dimensional- shaped product. CONSTITUTION:This device is equipped with a wrinkle press plate 25 holding a metal sheet 30 between a female die 20 whose opening part 21 is formed by plural corner parts 22 and ridgeline parts 23 and an outside surface 24 communicating with the opening part 21 of this female die 20, and a male die 28 pressurizing the metal plate 30 into the female die 20 inserted into the center opening part of this wrinkle press plate 25. The press forming of a metal sheet such as aluminum, an aluminum alloy, etc., is performed by a press forming device formed of plural hole parts 27... suppressing the flowing-in of the metal plate 30 in a position along with the ridgeline part 23 of at least either opening part 21 of the wrinkle keep plate 25 and the outside surface 24 of the female die 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press molding apparatus for molding a metal plate such as an aluminum plate into a desired shape and a press molding method using this apparatus.

[0002]

2. Description of the Related Art In general, a plate material such as aluminum having high workability is formed into a desired product by press forming. In such press forming, as shown in FIGS. 4 and 5, a punch (male mold) 2 having a desired shape for forming a plate material (workpiece) 1 and the punch 2 are the same as the plate material 1 described above. Using a press forming apparatus having a die (female die) 3 inserted at a predetermined interval corresponding to the thickness, the plate material 1 placed on the upper surface 4 of the die 3 is opened by the punch 2 in the die 3. By pressing into the part 5,
It is for molding into a product shape having a desired three-dimensional shape. Here, a wrinkle holding plate 8 having a smooth wrinkle holding surface 7 is provided at a position facing the upper surface 4 of the die 3, and the flange portion 6 of the plate material 1 placed on the upper surface 4 is disposed.
Are preliminarily clamped by the wrinkle holding plate 8.

In such press forming, the deformation which is an element for forming the plate material is the shrinking deformation of the flange portion 6 exclusively. However, as shown in FIG. 3, unlike the case of forming a cylindrical product such as a container such as a beverage can or a whiskey cap, a plurality of corners 10 such as an outer panel of an automobile and the corners 10 ... In the molding of a three-dimensional product defined by the connecting flat portion 11, the flow velocity of the material at the corner portion 10a is extremely small when the flange portion 12 is deformed.
The flow velocity of the material in the portion 11a along the ridge between the corners 10a is large, and as a result, a large difference in the flow velocity of the material causes a wrinkle on the surface of the molded product or a strain of the surface called surface strain. Will occur.

For this reason, in the conventional press-forming apparatus, as shown in FIGS. 4 and 5, by providing a protrusion called a bead 14 on a portion of the wrinkle holding surface 7 along the above-mentioned ridge line, the original material flow is prevented. The flow of the material is restrained in the portion where the speed is high to prevent the occurrence of the wrinkles.

[0005]

However, in the press forming using the above-mentioned conventional press forming apparatus, when the plate material is a steel plate, the forming can be performed without problems,
When the plate material is aluminum or an aluminum alloy plate, these metals are originally prone to seizure in the mold, so on the contrary, the resistance when passing through the bead 14 becomes abnormally high, and the material flows into the mold. There is a problem in that the material required for molding is not supplied because of the fact that it does not get stuck, so that the product part breaks. Also, the plate material is beads 14.
There is also a problem that the plate material is repeatedly bent when passing through the sheet, and as a result, the plate material is work-hardened and the formability is deteriorated.

For this reason, in order to reduce the passage resistance of the plate material in the bead 14, a method of increasing the viscosity of the lubricating oil attached to the wrinkle holding surface 7 and the like to prevent seizure can be considered. There is a drawback that it becomes difficult to remove it from the surface of the molded product later.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and in a press forming apparatus according to claim 1, an opening has a plurality of corners and these corners are connected to each other. A crease holding plate that holds the outer peripheral portion of the plate material between the female mold defined by the ridge line portion and the outer surface of the female mold that is continuous with the opening, and is inserted into the central opening of the wrinkle holding plate. A plurality of holes for suppressing the inflow of the plate material at a position along the ridge of the opening of at least one of the outer surface of the wrinkle holding plate and the female mold, Part is formed.

In the press-molding method according to the second aspect of the present invention, the opening is defined by a plurality of corners and a ridge line portion connecting the corners, and the opening of the female mold is formed in the female mold. At least one of the continuous outer surface and the opposing wrinkle retainer plate is formed at a position along the ridge of the opening, and a plurality of holes for suppressing the inflow of the plate material is formed, and then between the wrinkle retainer plate and the outer surface of the female mold. After the outer peripheral portion of the plate material is clamped by, the central portion of the plate material is pressed into the female mold by the male die inserted in the central opening of the wrinkle holding plate to form the plate material into a desired shape.

Further, in the press forming method according to claim 3, the plate material according to claim 2 is aluminum or an aluminum alloy, and the maximum opening size of the hole is 5 times the thickness of the work material. The hole portions are separated from each other by a distance of 5 times or less the hole diameter.

[0010]

According to the first and second aspects of the present invention, a plurality of corner portions such as an automobile outer panel and a plane portion connecting the corner portions are formed of a material such as aluminum or aluminum alloy. When molding a three-dimensional product defined by
Since the wrinkle pressing surface pressure between the above corners where the flow velocity of the material is originally high is increased, this increases the frictional resistance with the plate material at that portion and partially suppresses the material from flowing into the die. To be done. As a result, the difference in the flow velocity of the material between the corners and between the corners is reduced, and the formation of wrinkles and surface strain on the molded product is prevented.

Further, since the wrinkle holding surface where the hole is opened and / or the outer surface of the female mold is a flat surface, the material is not subjected to bending and bending back deformation unlike the conventional bead, so that the material is work hardened. Never.

Further, according to the invention of claim 3,
When aluminum or aluminum alloy is molded into the above-mentioned three-dimensional product, the plate material does not receive an abnormally high surface pressure in a very narrow range in the flange portion.
It is possible to prevent seizure from being formed on the female mold or the wrinkle holding surface in the flange portion. Here, the reason why the maximum opening size of the hole is set to be five times that of the work material is that when the maximum opening size of the hole exceeds the above value, the surface pressure acting on the plate material such as aluminum is ridged. This is because it becomes partially non-uniform along the direction, which leads to non-uniformity of the flow velocity of the material along the direction, which is inconvenient in molding. Furthermore, when the distance between the holes exceeds 5 times the hole diameter, Similarly, non-uniformity of the surface pressure occurs,
This is because wrinkles are more likely to occur.

[0013]

1 and 2 show an embodiment of the press forming apparatus of the present invention, in which reference numeral 20 is a die having a central opening 21. This press molding apparatus is for press-molding a bottomed rectangular tubular container having an R portion at a corner portion, and the opening 21 of the die 20 has four corners for molding the corner portion of the product. It is defined by the portions 22 and the linear ridge portions 23 that connect the corner portions 22 and form the side wall on the plane of the product.

On the upper surface (outer surface) 24 connected to the opening 21 of the die 20, a ring-shaped wrinkle pressing plate 25 is disposed so as to face the upper surface (outer surface) 24, and the straight edge line of the wrinkle pressing plate 25 is arranged. At the position along the portion 23 ...
A plurality of holes 27 ... Opening to the wrinkle holding surface 26 of No. 5 are formed. The holes 27 have a size of 2φ and are bored in plural rows (four rows in the figure) along the ridge portions 23. And these dice 20
In addition, in the opening of the wrinkle holding plate 25, a rectangular column-shaped punch (male type) 28 that substantially matches the inner surface shape of the product is formed in the die 2.
It is inserted movably toward 0.

Next, an embodiment of the press-molding method of the present invention using the press-molding apparatus having the above construction will be described. First, a plate material (workpiece) 30 made of substantially rectangular aluminum or aluminum alloy having a predetermined size obtained from the product size is prepared. Next, the plate member 30 is placed on the upper surface 24 of the die 20, and the outer peripheral portion 31 is sandwiched between the upper surface 24 and the wrinkle holding surface 26 of the wrinkle holding plate 25 with a predetermined pressure. Then, the punch 28 inserted into the central opening of the wrinkle holding plate 25 presses the central portion 32 of the plate material 30 into the die 20 to form the plate material 30 into a desired shape.

According to the molding method using such a press molding apparatus, a three-dimensional product having a corner portion and a flat portion connecting the corner portions, such as a rectangular tube-shaped container, can be obtained. At the time of molding, due to the large number of hole portions 27 formed along the ridge line portions 23 forming the flat portion,
The wrinkle pressing surface pressure between the corner portions 22 ... In which the flow velocity of the material is originally high is increased. Therefore, the frictional resistance between the plate material 30 and the wrinkle holding surface 26 is increased, and the material is partially suppressed from flowing into the die 20. Therefore, the difference in the material flow velocity between the corner portions 22 and the corner portions 22 ... Is reduced, so that wrinkles and surface strains are prevented from occurring in the molded product.

Further, since the wrinkle holding surface 26 in which the holes 27 ... Are opened is a flat surface, the plate material 3 is formed like a conventional bead.
Since no bending or bending back deformation is applied to 0, the material does not work harden.

Furthermore, since no abnormally high surface pressure acts on the plate material 30 in the flange portion in an extremely narrow range, seizure occurs between the plate material 30 and the wrinkle holding surface 26 in the flange portion. Never.

In the above embodiment, the die opening is defined by four corners and a straight ridge connecting the corners to form a rectangular cylindrical container. Although described above, the present invention is not limited to this, and the press molding apparatus and the press molding method according to the present invention have, for example, a plurality of corners such as an outer panel of an automobile and a gentle protruding curve shape connecting these corners. The same can be applied to the molding of a complicated three-dimensional shape defined by the ridge portion. Further, the cross-sectional shape of the hole is not limited to the circular shape, and the same effect can be obtained by forming a plurality of square-shaped hole portions.

[0020]

[Experimental example] Material is JIS A5182-0 and thickness is 1m
Corner plate with punch size of 400 x 400
Molding was performed using a press molding apparatus with a number of 30. In addition,
As an example of the present invention, one having a large number of holes having a diameter of 2 mm provided along the straight side portion of the wrinkle holding surface was used. Further, as a comparative example, a press molding apparatus provided with a bead in the above portion,
And a press molding device provided with nothing was used. As the lubricating oil, mineral oil having a kinematic viscosity of 32 cst at 40 ° C. was used. As shown in Table 1, as shown in Table 1, in the examples of the present invention, it was possible to perform press molding without breakage and wrinkles, but when a bead was provided, strong scuffing occurred at the bead portion, and fracture occurred at the rising of the straight side portion. did. Further, in the comparative example in which nothing is provided on the wrinkle holding surface, the wrinkles generated on the straight side part penetrate into the product part, and this wrinkle is eliminated by increasing the wrinkle holding force, but the breakage at the corner part Occurred.

[0021]

[0022]

As described above, according to the present invention as set forth in claims 1 and 2, a plurality of corner portions and a plane connecting the corner portions are made of a material such as aluminum or aluminum alloy. When molding a product having a three-dimensional shape defined by parts and parts, it is possible to easily prevent wrinkles and surface strains from being formed in the molded product, and the material is not bent and unbent and deformed. Does not work harden.

Further, according to the invention of claim 3,
When aluminum or aluminum alloy is molded into the above three-dimensional product, there is no risk of seizure between the plate material and the female mold or the wrinkle holding surface.

[Brief description of drawings]

FIG. 1 is a plan view of a main part showing an embodiment of a press molding apparatus of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a perspective view showing a deformed state of a molded product.

FIG. 4 is a plan view of a main part showing an example of a conventional press molding apparatus.

5 is a sectional view taken along line VV of FIG.

[Explanation of symbols]

 20 die (female type) 21 opening 22 corner 23 ridge line 24 upper surface (outer surface) 25 wrinkle holding plate 27 hole 28 punch (male type) 30 plate material (workpiece) 31 outer peripheral part 32 central part

Claims (3)

[Claims] 1. A wrinkle retainer plate for sandwiching an outer peripheral portion of a plate material between a female die having an opening and an outer surface of the female die connected to the opening, and a wrinkle retainer plate inserted into a central opening of the wrinkle retainer plate. In a press forming apparatus including a male die for pressing the central portion of the plate material into the female die, the opening of the female die is defined by a plurality of corners and a ridge line portion connecting the corners. And a plurality of hole portions that suppress the inflow of the plate material are formed at a position along the ridge line portion of the opening of at least one of the outer surface of the wrinkle holding plate and the female mold. Press forming equipment. 2. A female mold having an opening defined by a plurality of corners and a ridge line connecting the corners, and a wrinkle retainer plate facing an outer surface of the female mold continuous with the opening. Forming a plurality of holes for suppressing the inflow of the plate material at a position along the ridgeline portion of at least one of the openings, and then forming an outer peripheral portion of the plate material between the wrinkle holding plate and the outer surface of the female mold. A press-molding method, characterized by pressing the central portion of the plate member into the female mold by a male mold inserted into the central opening of the wrinkle retainer plate and then molding the plate member into a desired shape. 3. The plate material is aluminum or an aluminum alloy, and the maximum opening size of the hole is 5 times the thickness of the work material, and the holes are 5 times the hole diameter with respect to each other. The press molding method according to claim 2, wherein the following intervals are provided.