JP7454433B2 - Manufacturing method for hat-shaped molded parts and mold - Google Patents

Description

The present invention relates to a method for manufacturing a hat-shaped molded part and a mold.

2. Description of the Related Art A method of manufacturing a hat-shaped molded part by press-molding a substantially rectangular metal plate (steel plate) using a mold is known.

Patent Document 1 discloses a press forming method in which a substantially rectangular plate material is press-formed using a lower mold and an upper mold having rounded portions on the periphery. In this press forming method, the edges of two opposing sides of the plate material are held down by a blank holder, the edges of the other two sides are not held down, and the ends of the other two sides are held inward from the rounded part of the lower mold. By setting the trim line outward from the trim line, the yield of press-formed products is improved.

Japanese Patent Application Publication No. 11-57877

In the method for manufacturing a press-formed product of a substantially rectangular plate material as described above, the yield of the press-formed product is improved compared to the case where the entire circumference of the metal plate is held down by a blank holder. However, in a hat-shaped molded part, if there is molding in which excess material such as dents or protrusions occurs near the end of the metal plate (inside the product) that cannot be pressed by the blank holder, the generation of wrinkles cannot be controlled. Furthermore, wrinkles also occur outside the product (the outside of the product outside the mold line than the trim line), and the mold can be damaged by crushing the wrinkles that occur on the metal plate between the upper and lower molds. There is sex.

Therefore, the present invention reduces the occurrence of wrinkles inside the product near the edges of the metal plate that are not held by the blank holder, and also prevents damage to the mold by crushing the wrinkles that occur outside the product with the upper mold and the lower mold. The purpose is to suppress

A method for manufacturing a hat-shaped molded component according to one aspect of the present invention is a method of manufacturing a hat-shaped molded component by press-molding a metal plate having a pair of opposing long side portions and a pair of opposing short side portions. be. While at least one pair of long side portions of the metal plate are held by a blank holder, a drawing process is performed to form the metal plate into a hat shape using an upper die and a lower die. Further, at least one of the pair of short sides of the metal plate that is not held by the blank holder is bent in the vertical direction using an upper mold and a lower mold.

A mold according to one aspect of the present invention is a mold for manufacturing a hat-shaped molded part by press-molding a metal plate having a pair of opposing long side portions and a pair of opposing short side portions. The mold includes an upper mold and a lower mold that face each other in the vertical direction, and a blank holder that holds at least one pair of long side portions of the metal plate. The upper mold and the lower mold are configured to bend in the vertical direction at least one of a pair of short side portions of the metal plate that are not held by the blank holder. The gap between the upper mold and the lower mold at the bottom dead center is larger than the thickness of the metal plate at the outside of the mold at the part where the metal plate is bent in the vertical direction by bending.

According to the manufacturing method and die for hat-shaped formed parts according to one embodiment of the present invention, even in cases where molding produces excess material such as dents or protrusions near the ends of the metal plate not held by the blank holder (parts within the product), the occurrence of wrinkles is reduced and a highly accurate press-formed product can be obtained. Furthermore, even if wrinkles occur in parts outside the product, damage to the die caused by the wrinkles being crushed by the upper and lower dies can be suppressed.

1 is a perspective view of a hat-shaped molded part press-molded using a mold according to an embodiment of the present invention. FIG. 1 is a sectional view of a mold according to an embodiment of the present invention. It is a perspective view of a lower die and a blank holder. It is a perspective view of a blank material, a lower die, and a blank holder after press forming. It is an explanatory view of the process of bending a metal plate. FIG. 3 is an explanatory diagram of a process of bending a metal plate. FIG. 3 is an explanatory diagram of a process of bending a metal plate. It is an explanatory view of the process of bending a metal plate. FIG. 2 is an enlarged cross-sectional view of the main parts of the upper die and the lower die at the bottom dead center.

Embodiments of the present invention will be described in detail below with reference to the drawings.

Hereinafter, a method for manufacturing a hat-shaped molded part 1 (see FIG. 1) having a hat-shaped cross section and a mold 10 (see FIG. 2) used for press-molding the hat-shaped molded part 1 will be described as an example.

A hat-shaped molded part 1 shown in FIG. 1 is called a center pillar outer reinforcement, and is a reinforcing part formed inside the center pillar of a vehicle, and is generally made of a high-tensile steel plate or the like. be done.

In addition, in FIG. 1, the reference numeral 20 indicates a press-molded product to which a center pillar outer reinforcement (hat-shaped molded part 1) is coupled, and is called a roof side rail outer.

As shown in FIG. 1, the hat-shaped molded part 1, like the blank material 2 that is the raw material of the hat-shaped molded part 1, has a pair of opposing long sides 3a, 3b and a pair of opposing short sides 4a. , 4b, and is formed into a substantially rectangular shape.

The hat-shaped molded part 1 has an overall shape including a top plate part 5, a pair of side walls 6, and a flange part 7 extending from the side walls 6 to the outside in the transverse direction of the hat-shaped molded part 1. It is formed into a hat-shaped cross section.

The method for manufacturing the hat-shaped molded part 1 according to the present embodiment includes the following steps. All steps in the method for manufacturing the hat-shaped molded part 1 according to this embodiment are performed by press working using a mold.

Specifically, the method for manufacturing the hat-shaped molded part 1 according to the present embodiment includes a process of blanking, a process of press forming (drawing, bending), a process of trimming, and other processes. and a process to perform the process.

Each step will be explained below.

1. Blank Processing In this step, in order to mold an elongated, substantially rectangular hat-shaped molded part 1, a metal plate (blank material) 2, which is a substantially rectangular flat plate in plan view, is prepared (manufactured). The blank material 2 is, for example, a steel plate such as SPFC (workable cold-rolled high-strength steel plate for automobiles), has a tensile strength of 340 N/mm ² or more, and has a thickness (plate thickness) T (Fig. 5 A steel plate with a diameter of 1.0 mm to 2.3 mm (see Reference) is used.

In this embodiment, SPFC (workable cold-rolled high-strength steel plate for automobiles) with a tensile strength of 1470 N/mm ² and a plate thickness T of 1.6 mm is used as the blank material 2.

The blank material 2 has an outer shape developed into a flat plate shape from the shape of the hat-shaped molded part 1 which is a product (finished product). Therefore, the blank material 2 is formed into a substantially rectangular shape having at least a pair of opposing long side portions 3a, 3b and a pair of opposing short side portions 4a, 4b.

This process of performing blanking is a commonly performed process, and therefore a detailed explanation will be omitted.

2. Press forming (drawing, bending)
In this step, the blank material 2 is press-molded using a mold 10 (an upper mold 11 and a lower mold 13) into an elongated, substantially rectangular hat-shaped molded part 1.

As shown in FIGS. 2 and 3A, a mold 10 used for press forming (drawing, bending) includes, for example, an upper mold 11 (die 12) and a lower mold 13 (punch 14) that face each other in the vertical direction. , a blank holder 15, and a cushion pin 16.

The drawing process in this embodiment is performed using an upward drawing die having the above configuration.

In this embodiment, the entire circumference of the blank material 2 is not held (blank held) by the blank holder 15 and press-formed. In this embodiment, a pair of opposing long side portions 3a and 3b of the blank material 2 are held by a blank holder 15, and a pair of opposing short side portions 4a and 4b are press-formed without being held by the blank holder 15.

The step of press-forming the blank material 2 into a hat-shaped cross section while holding it by the blank holder 15 is a drawing step. The drawing process in this embodiment is performed in one process (single stage), but if the depth of the hat-shaped cross section is deep (the height of the side wall portion 6 is high), the drawing process is performed in multiple stages (multi-stages). It is also possible.

Below, the processing procedure of a pair of long side parts 3a and 3b in which the drawing process of the blank material 2 is performed will be explained using FIG. 3A and FIG. 3B.

FIG. 3A shows a blank holder 15 that holds a pair of long side portions 3a and 3b of the blank material 2. As shown in FIG.

The blank material 2 is held on a blank holder 15 in a state where an upper die 11 (die 12) and a lower die 13 (punch 14) set in a press machine (not shown) are open.

Due to the operation of the press machine, the pair of opposing long side portions 3a and 3b of the blank material 2 are held between the die 12 and the blank holder 15.

Next, press forming is started, and the blank material 2 held between the die 12 and the blank holder 15 is drawn using the punch 14. This drawing process is started prior to the bending process described later.

Then, when the drawing process further progresses and the upper die 11 reaches the position of the press bottom dead center (bottom dead center), the press forming (drawing process) is completed, as shown in FIG. 3B.

Among the pair of opposing short side portions 4a and 4b of the blank material 2, one short side portion 4b is not held by the blank holder 15 and is bent. The bending process in this embodiment is performed only on one short side portion 4b, but depending on the shape (product shape) of the hat-shaped molded part 1 (for example, bumper reinforcement), the pair of short side portions 4a, It is also possible to perform this for both 4b.

Below, the processing procedure of the short side portion 4b in which the bending process of the blank material 2 is performed will be explained using FIGS. 4A to 4D.

4A to 4D are schematic cross-sectional views of the short side portion 4b (longitudinal direction of the top plate portion 5) of the blank material 2, which is bent without being held by the blank holder 15, from the start of press forming. The process steps for bending until press forming is completed are shown.

As shown in FIG. 4A, press forming is started, and the drawing process of the blank material 2 held between the die 12 and the blank holder 15 is started prior to the bending process, and the convex shape in the lower mold 13 (punch 14) is started. The apex portion (lower die apex portion) 17 contacts the blank material 2.

As shown in FIG. 4B, the drawing process further progresses, and the short side portion 4b of the blank material 2 that is not held by the blank holder 15 is lifted up into a convex shape by the lower die 13 (punch 14) and the upper die 11 (die 12). The bending process begins.

As shown in FIG. 4C, the bending process further progresses, and the convex apex portion (upper mold apex portion) 18 of the upper die 11 (die 12) comes into contact with the blank material 2.

As shown in FIG. 4D, the bending process further progresses and when the upper mold 11 reaches the bottom dead center of the press, the press forming (bending process) is completed.

When the blank material 2 is press-formed as shown in FIG. 3B, the short side portion 4b of the blank material 2 that is not held by the blank holder 15 is bent in the vertical direction and becomes convex, as shown in FIGS. 4A to 4D. formed into a shape. By doing so, the blank material 2 is formed in the longitudinal direction by the convex portion of the short side portion 4b that is not held by the blank holder 15 and the pair of long side portions 3a and 3b that are held between the die 12 and the blank holder 15. It is press-formed while being stretched.

Even if an excess of material such as a dent or a protrusion is generated in the top plate portion 5 or side wall portion 6 near the end of the hat-shaped molded part 1 due to blank holding in the transverse direction and tension in the longitudinal direction of the blank material 2, the edge The occurrence of wrinkles near the area (inside the product) is reduced. Therefore, according to this embodiment, it is possible to obtain a press-molded product (hat-shaped molded part 1) with high precision.

At the end of the hat-shaped molded part 1 in the longitudinal direction (short side portion 4b), by drawing in the short direction and bending in the longitudinal direction, a surplus of material is generated, resulting in a convexity. More wrinkles may occur on the outer side of the mold than on the lower mold apex 17. However, the portion where many wrinkles have occurred in the blank material 2 after press-forming is removed from the hat-shaped molded part 1 which is finally cut and becomes a product (trim cut).

As shown in FIG. 5, in this embodiment, the gap (distance) between the upper die 11 and the lower die 13 at the bottom dead center of the press is at the lower die vertex 17 where the blank material 2 is bent into a convex shape by bending. , is equivalent to the thickness T of the blank material 2 (gap Ga). This gap (gap in the direction perpendicular to the tangential direction of the mold) is gradually increased from the lower mold apex 17 toward the outside in the longitudinal direction (outside of the mold) of the blank material 2, and at the outermost part of the mold, the "plate thickness The gap Gb is "T+predetermined thickness".

In this embodiment, the above-mentioned predetermined thickness is 3.0 mm, and the gap between the upper mold 11 and the lower mold 13 at the bottom dead center of the press is 4.6 mm (1.6 mm) at the outermost part of the mold. (plate thickness T)+3.0 mm (predetermined thickness)) (gap Gb).

On the other hand, the gap between the upper die 11 and the lower die 13 at the bottom dead center of the press is located inside the blank 2 in the longitudinal direction (inner side of the die) than the lower die apex 17 that bends the blank 2 into a convex shape by bending ), it is assumed to be equivalent to the thickness T of the blank material 2 (gap Gc). The part of the blank material 2 that is inside the mold from the lower mold apex 17 is held between the die 12 and the blank holder 15 and press-formed while being stretched in the width direction, so the material stretches and wrinkles occur in this part. This is because it is difficult to occur.

In the press forming described above, a pair of opposing long sides 3a and 3b of the blank material 2 are held between a die 12 and a blank holder 15, and one of the pair of short sides 4a and 4b (short side part 4b) is An example of bending is shown. However, depending on the shape (product shape) of the hat-shaped molded part 1, a pair of opposing long sides 3a and 3b of the blank material 2 may be held between the die 12 and a blank holder 15, and a pair of short sides It is also possible to perform bending on both portions 4a and 4b.

3. Trimming process In this process, the unnecessary outer peripheral part (portion outside the product) of the short side part 4b of the hat-shaped molded part 1 after press molding is trimmed (cut, removed) using a mold, and the product is The external shape is determined.

In this embodiment, trimming is performed on the short side portion 4b of the hat-shaped molded part 1 after press molding at the trim line TL (see FIG. 3B) that is inside the mold from the lower mold apex 17.

The process of performing this trimming process itself is a commonly performed process, and therefore detailed explanation will be omitted.

4. Other Processing In addition to the above-mentioned processes, other processes are also performed.

In other processes, for example, after the process of trim cutting, the distortion remaining in the hat-shaped molded part 1 is corrected, and the surface accuracy of the part of the hat-shaped molded part 1 where it is assembled with other parts is improved. Restrike processing is performed. Further, for example, piercing holes are formed in the hat-shaped molded part 1 to be used when assembling with other parts.

The restriking process and the piercing process, which are examples of other processes, are commonly performed processes and are therefore not described in detail.

The effects of this embodiment will be explained below.

(1) The method for manufacturing the hat-shaped molded part 1 according to the present embodiment includes press-molding a blank material 2 having a pair of opposing long side portions 3a, 3b and a pair of opposing short side portions 4a, 4b. This is a method of manufacturing a hat-shaped molded part 1. With at least one pair of long side portions 3a and 3b of the blank material 2 held by the blank holder 15, drawing processing is performed to form the blank material 2 into a hat shape using the upper mold 11 and the lower mold 13. At least one of the pair of short side portions 4a, 4b of the blank material 2 that is not held by the blank holder 15 is bent in the vertical direction using the upper die 11 and the lower die 13.

By bending the short side portion 4b of the hat-shaped molded part 1 into a convex shape in the press forming process, the blank material 2 can be press formed (drawn) while being stretched in the longitudinal direction. Therefore, the occurrence of wrinkles near the end of the short side portion 4b (inside the product) of the blank material 2 that is not held by the blank holder 15 is reduced, and the hat-shaped molded part 1, which is a highly accurate press-formed product, is reduced. Obtainable.

Further, according to the method for manufacturing the hat-shaped molded part 1 according to the present embodiment, press molding can be performed using a general mold structure such as the punch 14, die 12, and blank holder 15, and productivity can be improved. A high quality hat-shaped molded part 1 can be produced without dropping.

(2) The drawing process is started before the bending process.

By doing this, press forming (drawing) can be performed while pulling the blank material 2 in the longitudinal direction, and the short side portion 4b (part inside the product) of the blank material 2 that is not held by the blank holder 15 is Even if there is molding that causes excess, the occurrence of wrinkles is reduced.

(3) The gap between the upper mold 11 and the lower mold 13 at the bottom dead center is determined by the thickness of the blank material 2 on the outside of the mold from the point where the blank material 2 is bent in the vertical direction during bending (lower mold apex 17). It is larger than T (gap Gb).

Even if wrinkles occur in the short side portion 4b (portion outside the product) of the hat-shaped molded part 1 during the press molding process, the wrinkles are prevented from being crushed by the mold 10 (upper mold 11 and lower mold 13). Therefore, damage to the mold 10 can be effectively suppressed.

(4) After the process of drawing and bending, a trim cut process is performed to cut and remove the portion of the blank material 2 that has been bent by the bending process.

After press molding, by cutting and removing unnecessary outer peripheral portions (portions outside the product) of the short side portions 4b of the hat-shaped molded component 1, it is possible to improve the product quality of the hat-shaped molded component 1. It is.

(5) The mold 10 according to the present embodiment is produced by press-molding a blank material 2 having a pair of opposing long side portions 3a, 3b and a pair of opposing short side portions 4a, 4b to produce a hat-shaped molded part. 1. The mold 10 includes an upper mold 11 and a lower mold 13 that face each other in the vertical direction, and a blank holder 15 that holds at least one pair of long side portions 3a and 3b of the blank material 2. The upper die 11 and the lower die 13 are configured to bend at least one of the pair of short side portions 4a, 4b of the blank material 2 that is not held by the blank holder 15 in the vertical direction. The gap between the upper mold 11 and the lower mold 13 at the bottom dead center is larger than the thickness T of the blank material 2 at the outside of the mold from the point where the blank material 2 is bent in the vertical direction during bending (lower mold apex 17). is also large (gap Gb).

By bending the short side portion 4b of the hat-shaped molded part 1 into a convex shape in the press forming process, the blank material 2 can be press formed (drawn) while being stretched in the longitudinal direction. Therefore, the occurrence of wrinkles in the short side portion 4b (inside the product) of the blank material 2 that is not held by the blank holder 15 is reduced, and the hat-shaped molded part 1, which is a highly accurate press-formed product, can be obtained. .

Even if wrinkles occur in the short side portion 4b (portion outside the product) of the hat-shaped molded part 1 during the press molding process, the wrinkles are prevented from being crushed by the mold 10 (upper mold 11 and lower mold 13). Therefore, damage to the mold 10 can be effectively suppressed.

Further, according to the mold 10 according to the present embodiment, press molding can be performed using a general mold structure such as the punch 14, the die 12, and the blank holder 15, and high quality can be achieved without reducing productivity. hat-shaped molded parts 1 can be produced.

By the way, although the method for manufacturing a hat-shaped molded part of the present invention has been explained by taking the above-mentioned embodiment as an example, it is not limited to this embodiment, and various other embodiments may be adopted without departing from the gist of the present invention. be able to.

1 Hat-shaped molded part (center pillar outer reinforcement)
2 Blank material (metal plate)
10 Mold 11 Upper mold 13 Lower mold 15 Blank holder 17 Convex apex (lower mold apex)
T Thickness (plate thickness)
Gb Gap TL Trim line

Claims (4)

A method of manufacturing a hat-shaped molded part by press-molding a metal plate having a pair of opposing long side portions and a pair of opposing short side portions, the method comprising:
While at least the pair of long side portions of the metal plate are held by a blank holder, a drawing process is performed to form the metal plate into a hat shape using an upper die and a lower die, and
performing a bending process of bending at least one of the pair of short sides of the metal plate not held by the blank holder in the vertical direction using the upper die and the lower die;
starting the drawing process prior to the bending process;
A method for manufacturing hat-shaped molded parts. According to claim 1 , the gap between the upper die and the lower die at the bottom dead center is larger than the thickness of the metal plate at a position outside the die where the metal plate is bent in the vertical direction by the bending process. A method for manufacturing a hat-shaped molded part. Manufacturing the hat-shaped molded part according to claim 1 or 2 , wherein after the drawing process and the bending process, a trim cut process is performed to cut and remove a portion of the metal plate bent by the bending process. Method. A mold for manufacturing a hat-shaped molded part by press-molding a metal plate having a pair of opposing long side parts and a pair of opposing short side parts,
An upper mold and a lower mold facing each other in the vertical direction;
a blank holder that holds at least the pair of long side portions of the metal plate,
The upper mold and the lower mold include a drawing process in which the metal plate is formed while being held by the blank holder, and at least one of the pair of short sides of the metal plate that is not held by the blank holder is vertically moved . a bending process is performed, and the drawing process is started prior to the bending process ,
The gap between the upper mold and the lower mold at the bottom dead center is larger than the thickness of the metal plate at the outside of the mold than at the part where the metal plate is bent in the vertical direction by the bending process .
Mold.

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