JP7261826B2 - Method for manufacturing press-molded products - Google Patents

Description

The present invention relates to a method of manufacturing a press-formed product using a press machine.

Conventionally, as a press device for drawing a blank material, one having a die, a punch, and a blank holder is known. In such a pressing device, a part having a predetermined shape is formed by lowering the die and the blank holder together while holding the blank between them and pressing the blank material against the punch.

Here, when drawing is performed using a pressing device, if the die contacts the blank before the blank is clamped between the die and the blank holder (previous contact), it causes problems such as panel deformation. In order to address such a problem of front contact, for example, Patent Document 1 below discloses that a stepped portion is provided between a molding surface (recess) provided in an upper mold and a holding surface so that the held blank is A stamping die is disclosed with first contact flats. In the press molding die of Patent Document 1, it is said that by providing a flat portion, the pressure at the contact point is dispersed to lower the surface pressure, thereby suppressing the occurrence of defects such as draw marks.

JP 2019-42780 A

As described above, conventionally, measures have been taken to suppress defects such as panel deformation caused by frontal impact by providing a stepped portion. That is, conventionally, in order to avoid the front hit, the position of the blank holder (die face) is lowered with respect to the drawing surface of the die, and the position of the holding surface that holds the blank against the position of the drawing surface It was configured to lower the height (configured with a stepped portion).

However, the stepped portion is a portion to be removed in the final product (part). As a result, a large amount of material (blank) needs to flow in order to form the stepped portion, and the portion that is finally removed (excess portion) increases, which is a factor in lowering the yield. Therefore, there has been a demand for a technology capable of improving the quality of press-formed products while improving the yield.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method of manufacturing a press-formed product that can improve the yield and improve the quality of the press-formed product.

(1) A method for producing a press-formed product of the present invention, which is provided to solve the above-described problems, is a method for producing a press-formed product by forming a blank using a press machine, wherein the press-formed product is approximately It has a flat surface, and a concave portion forming a negative angle with respect to a direction intersecting the surface is formed at the edge of the surface, and the press machine presses the blank. It has a die and a punch, a first holding member that supports the blank from below, and a second holding member that presses and holds the blank against the first holding member, and narrows a part of the blank. and a first forming step of drawing the blank after the holding step, wherein in the holding step, a part of the blank is formed into the first holding member and the second holding member In the first forming step, the die is moved relative to the punch while the blank is held by the first holding member and the second holding member to form the punch The drawing is performed by pressing the blank between the die and the die.

In the method of manufacturing a press-formed product of the present invention, before the die contacts the blank (before the die hits), the material is held by the first holding member (lower blank holder) and the second holding member (upper blank holder). . Therefore, in the method of manufacturing a press-formed product of the present invention, it is possible to avoid the die from hitting the blank before it is gripped (preliminary contact) and raise the position of the blank holder (die face). As a result, it is possible to hit the die while tension is applied to the blank without providing a height difference (stepped portion) between the drawing surface and the clamping surface of the die. As a result, the method for producing a press-formed product of the present invention can suppress buckling and cracking, and improve quality and formability.

In addition, in the method of manufacturing a press-formed product of the present invention, since it is not necessary to provide a stepped portion, the depth of drawing (drawing amount) can be reduced (shallow drawing is possible). That is, in the method of manufacturing a press-formed product of the present invention, shallow drawing can be performed without providing a conventionally provided stepped portion, so that the amount of inflow of material can be reduced (the amount of blank required for drawing can be reduced). actual length can be reduced). As a result, the production method of the press-formed product of the present invention can improve the yield. In addition, in the method of manufacturing a press-formed product of the present invention, shallow drawing can be performed, so that the inflow of material can be reduced while the formability can be improved as compared with the conventional technology.

(2) In the method for manufacturing a press-formed product of the present invention, the second holding member and the first holding member are step-formed to form a step-shaped bead portion near the end of the blank. A portion may be provided, and the stepped bead portion may be formed in the holding step.

According to the above-described configuration, the size of the bead can be reduced as compared with a conventional arcuate or trapezoidal bead (concavo-convex bead). As a result, in the method of manufacturing a press-formed product of the present invention, the actual length of the blank for forming the bead can be reduced, and the yield can be improved.

More specifically, in the prior art, stepped portions and uneven beads were provided, and the stepped portions and uneven beads were used as hooks for the blank during the drawing process (see FIG. 8(b)).

On the other hand, in the method of manufacturing a press-formed product of the present invention, it is not necessary to provide a stepped portion, and shallow drawing can be achieved. In addition, by making the bead step-shaped (step-shaped bead portion), even if the bead is made small, the blank can be sufficiently hooked and stopped during drawing (suppressing the positional deviation of the blank). can be done). As a result, in the method of manufacturing a press-formed product of the present invention, the actual length of the blank for forming the bead or forming the stepped portion (for example, the blank W1 from the portion Y1 to the portion Y2 in FIG. 5(b) distance L1) can be reduced, and the yield can be improved.

(3) In the method for manufacturing a press-formed product of the present invention, the second holding member and the first holding member are step-formed to form a step-like bead portion, which is a step-like bead, near the end of the blank. a second forming step of bending the blank with the bending blade after the first forming step; and in the holding step, The step-like bead portion may be formed, and the step-like bead portion may function as a positioning portion of the blank in the second molding step.

According to the above configuration, the stepped bead shape (stepped bead portion) can be used as a positioning portion of the blank during bending (second forming step).

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the press-formed product which can contribute to the improvement of a yield and the quality improvement of a press-formed product can be provided.

1(a) is an example of a part manufactured by the method for manufacturing a press-formed product of the present invention, and FIG. 1(b) is a cross-sectional view taken along line A-A' in FIG. 1(a). 1 is a schematic diagram showing a press device used in the method for producing a press-formed product of the present invention; FIG. It is a schematic diagram which shows the holding process of the manufacturing method of the press-formed product of FIG. It is a schematic diagram which shows the 1st shaping|molding process of the manufacturing method of the press-formed product of FIG. It is a schematic diagram which shows the 1st shaping|molding process of the manufacturing method of the press-formed product of FIG. It is a schematic diagram which shows the 2nd shaping|molding process of the manufacturing method of the press-formed product of FIG. It is a schematic diagram which shows the 2nd shaping|molding process of the manufacturing method of the press-formed product of FIG. It is a reference drawing which shows the process of the manufacturing method of the conventional press-formed product. It is a reference drawing which shows the process of the manufacturing method of the conventional press-formed product. It is a reference diagram showing a press-formed product formed by a conventional method of manufacturing a press-formed product.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of the manufacturing method of the press-formed product of this invention is described, referring drawings.

The method of manufacturing a press-formed product is a method of forming a blank W1 using a press device 10 to produce a press-formed product W2. In the following description, an example of the press-formed product W2 and each configuration of the press device 10 will be described, and then a method for manufacturing the press-formed product will be described.

The press machine 10 forms a plate-like metal material (hereinafter simply referred to as "blank W1"). The blank W1 is made of a metal plate, such as a steel plate, especially a high-tensile material. In the following description, a molded product (press-molded product) obtained by press-molding the blank W1 may be simply referred to as a "press-molded product W2". Also, the product obtained by removing the surplus portion of the press-formed product W2 may be simply referred to as "part W3".

The press machine 10 is capable of molding various parts such as automobile roofs, fenders, hoods, front doors and rear doors. FIG. 1(a) shows an example of a part W3 after removing an excess portion of a press-formed product W2 formed by the method of manufacturing a press-formed product according to the present embodiment. The part W3 is used as the roof of the automobile (part W3).

As shown in FIG. 1(b), the component W3 has a portion (dent portion B) that is recessed inward in the rear portion in the front-rear direction when attached to the vehicle. More specifically, the recessed portion B formed in the rear portion of the component W3 is a recessed portion that forms a negative angle with respect to the vertical direction in a cross-sectional view. That is, the part W3 has a substantially flat surface that constitutes the ceiling surface (roof portion) of the vehicle. A portion (recess portion B) is formed. In addition, the recessed portion B shown in FIG. 1(b) is a portion formed to secure the rotation track of the back door.

It should be noted that the method of manufacturing a press-formed product of the present invention is not limited to the case of forming a roof, and can be used to manufacture various parts.

As shown in FIG. 2, the press apparatus 10 includes a die 20, a punch 30, a lower blank holder 40 (first holding member), and an upper blank holder 50 ( second holding member). Further, as shown in FIG. 6, the press device 10 is provided with a bending blade 70, a bending die 72, an upper blank holder 74, and a lower blank holder 76 as components used in the second forming step. The die 20 and the punch 30 move relatively in the vertical direction so as to approach or separate from each other to press the blank W1 for press working.

In the press device 10 of this embodiment, the die 20 can be moved up and down relative to the punch 30 . More specifically, in the press apparatus 10 of the present embodiment, the die 20 is attached to an upper die body (not shown) that can be moved up and down. Also, the punch 30 and the lower blank holder 40 are attached to a lower die main body (not shown). That is, in the press apparatus 10 of this embodiment, the die 20 is movable and the punch 30 is fixed.

As shown in FIG. 2, the lower surface of the die 20 is formed with a drawing surface 22 for holding the blank W1 between itself and the punch 30 and for drawing the blank W1. The punch 30 also has a draw forming surface 32 for drawing the blank W1 together with the draw forming surface 22 of the die 20 .

In the following description, the elevation direction (vertical direction) of the die 20 may be simply referred to as the ``vertical direction H'' or ``vertical direction H''.

A lower blank holder (first holding member) 40 and an upper blank holder 50 (second holding member) are for sandwiching and holding the end of the blank W1 before molding the blank W1.

As shown in FIG. 3A, the lower blank holder 40 holds the blank W1 by supporting it from below. As shown in FIG. 3( a ), the upper blank holder 50 is provided above so as to face the lower blank holder 40 . The upper blank holder 50 presses and holds the blank W1 against the lower blank holder 40 (see FIG. 3(b)).

In other words, the lower blank holder 40 and the upper blank holder 50 are placed in the blank W1 at a stage prior to a forming process such as drawing or bending (before the first forming process or the second forming process). It functions as a holding member that holds the The lower blank holder 40 is attached to the lower die body via a cylinder (not shown) and is movable in the vertical direction H relative to the punch 30 .

In this manner, the lower blank holder 40 and the upper blank holder 50 function as holding members that sandwich and hold the blank W1 before drawing or bending is performed. In other words, the upper surface (die face 41) of the lower blank holder 40 and the lower surface of the upper blank holder 50 form a clamping surface F that clamps the blank W1.

In the following description, of the upper surface of the lower blank holder 40, the surface that contacts the blank W1 (the surface that grips the blank W1) may be simply referred to as "die face 41".

As described above, the upper blank holder 50 and the lower blank holder 40 hold the blank W1 until the first forming process is completed. Also, the upper blank holder 74 and the lower blank holder 76 are used to hold the blank W1 in the second forming process.

As shown in FIG. 2 , the lower blank holder 40 and the upper blank holder 50 are provided with step forming portions 60 . The step-forming portion 60 is provided to form a step-like bead (step-like bead portion Ws) near the end portion of the blank W1 (see FIG. 3(b)).

More specifically, as shown in FIG. 2, the upper surface (die face 41) of the lower blank holder 40 is provided with a lower step forming portion 61 formed in a step shape. An upper side step molding portion 62 is provided on the side. The lower step-forming portion 61 and the upper step-forming portion 62 form a step for forming a step-shaped portion (step-shaped bead portion Ws) by holding the vicinity of the end portion of the blank W1 in pairs. It forms a molded portion 60 (see FIG. 3(b)).

As shown in FIG. 2, the step forming portion 60 is shaped such that the holding surface F on the outer edge side of the blank W1 is lowered by one step from the holding surface F on the die 20 side. That is, the step forming portion 60 has a wall surface Fa formed substantially vertically so as to connect holding surfaces F formed at different positions in the vertical direction H, and has a stepped (step-like) shape. ing.

Further, the stepped portion 60 is formed such that the angle formed by the substantially horizontal holding surface F and the wall surface Fa is approximately a right angle. Therefore, the step forming portion 60 is formed so as not to form a negative angle with respect to an approaching direction X of a bending blade, which will be described later (see FIG. 6).

As shown in FIG. 6, the lower blank holder 76 and the upper blank holder 74 are provided with step locking portions 80 . The step engaging portion 80 has substantially the same shape (step height, etc.) as the step forming portion 60 . The step locking portion 80 hooks the step-shaped bead portion Ws during bending to position the blank W1.

The bending blade 70 and the bending die 72 are for forming the recessed portion B at the end of the blank W1 (see FIG. 6). As shown in FIG. 6B, the bending blade 70 is movable with respect to the blank W1 at a predetermined angle with respect to the elevation direction H of the die 20 (approaching direction X having an angle θ with respect to the elevation direction H). It forms a negative angle portion (recess portion B) in the blank W1.

The bending blade 70 is provided at the tip of a cam (not shown), and is pushed by the cam so as to approach the bending die 72 .

<Each step in the method of manufacturing a press-molded product>
Next, the method for manufacturing the press-formed product of the present invention will be described.

The method of manufacturing the press-formed product of the present embodiment includes a holding step of holding a part (end portion) of the blank W1, a first forming step of drawing the blank W1, and a bending process of the blank W1. and a second forming step.

The press device 10 shown as an example in this embodiment includes a plurality of processing areas, and after the holding process and the first forming process are performed in a predetermined processing area, the blank W1 is conveyed to another processing area. A second molding step is performed. Although the present embodiment shows an example in which the first forming step and the second forming step are performed in a plurality of processing areas (in different processing areas), the present invention is not limited to this embodiment, and one processing The holding step, the first forming step, and the second forming step may be performed in the area. Each step will be described in detail below.

<Holding process>
In the holding step, a portion (end portion) of the blank W1 is held between the lower blank holder 40 and the upper blank holder 50 to form a stepped bead portion Ws. More specifically, first, the blank W1 is placed on the die face 41 of the lower blank holder 40 as shown in FIG. 3(a).

Further, as shown in FIG. 3B, the upper blank holder 50 is lowered to press the upper blank holder 50 against the lower blank holder 40, and the blank W1 is held between the upper blank holder 50 and the lower blank holder 40. do. As a result, the ends of the blank W1 are clamped and held by the lower blank holder 40 and the upper blank holder 50 .

As shown in FIG. 3(b), in the holding process, the blank W1 is held between the lower blank holder 40 and the upper blank holder 50, and is pressed by the lower step forming portion 61 and the upper step forming portion 62 to hold the blank W1. A step-like bead (step-like bead portion Ws) is formed at the end of the .

<First molding process>
After the holding step, a first forming step is performed. In the first forming step, the die 20 moves relative to the punch 30 while the blank W1 is sandwiched between the lower blank holder 40 and the upper blank holder 50, and the blank is formed between the punch 30 and the die 20. W1 is pressed and drawing is performed.

More specifically, as shown in FIG. 4A, the die 20 descends toward the punch 30 while the blank W1 is held between the lower blank holder 40 and the upper blank holder 50. As shown in FIG. As a result, the blank W1 is pressed against the drawing surface 32 of the punch 30 to start drawing. Here, since the blank W1 is held between the lower blank holder 40 and the upper blank holder 50, the blank W1 is pushed in under tension. Further, as shown in FIG. 4(b), as the die 20 moves downward, the blank W1 is pushed by the two raised portions 22a and 22b formed on the drawing surface 22. As shown in FIG.

As shown in FIG. 5(a), the die 20 is further lowered thereafter, and when the die 20 reaches the lower end position (bottom dead center), the drawing of the blank W1 is completed. In this way, the blank W1 is shaped along the drawing surface 22 of the die 20, as shown in FIG. 5(b).

Here, as shown in the reference diagram of FIG. 8A, in the conventional method of manufacturing a press-formed product, the die 120 is formed integrally with the drawing surface 122 and the holding surface 124 of the blank W1. It had been. In addition, conventionally, in order to avoid the die 120 from contacting the blank W1 (preliminary contact) before the blank W1 is sandwiched between the die 120 and the blank holder 140, the drawing surface 122 of the die 120 The position of the blank holder 140 (the die face 141) is lowered, and the position of the holding surface F' for holding the blank against the position of the drawing surface 122 is lowered (the stepped portion 126 is provided). rice field.

However, as shown in FIG. 10, the portion corresponding to the stepped portion 126 (stepped portion Wc) is a portion to be removed (removed portion E) in the final product (component). Therefore, a large amount of material (blank W1) needs to flow in order to form the stepped portion 126, and the portion to be finally removed (removed portion E) increases, causing a decrease in yield. Specifically, as shown in FIG. 10, in a press-formed product W2' formed using a die 120 having a stepped portion 126, a portion corresponding to the stepped portion 126 (stepped portion Wc) becomes a removed portion E, and is removed. The length L2' of the portion E becomes large.

In contrast, in the method of manufacturing a press-formed product of this embodiment, the material is gripped by the lower blank holder 40 and the upper blank holder 50 before the die 20 contacts the blank W1 (before the die hits). Therefore, in the method of manufacturing a press-formed product of the present embodiment, it is possible to avoid the die hitting the blank (first hit) before gripping the blank W1, and raise the position of the upper blank holder 50 . As a result, it is not necessary to provide a height difference (stepped portion 126) between the drawing surface 22 of the die 20 and the holding surface F, and the die 20 can be hit while the blank W1 is under tension. can. As a result, the method for producing a press-formed product according to the present embodiment can suppress buckling and cracking, and improve quality and formability.

Moreover, in the method of manufacturing a press-formed product of the present invention, it is not necessary to provide the stepped portion 126 . Therefore, as shown in FIG. 5B, in the method for manufacturing a press-formed product of the present embodiment, the depth of drawing (the amount of drawing M, the depth from the portion Y1 to the portion Y2 in FIG. 5B) can be reduced (shallow drawing is possible). That is, in the method for manufacturing a press-formed product of the present embodiment, shallow drawing can be performed without providing the conventionally provided stepped portion 126, so that the inflow amount of the material can be reduced. The actual length L1 of the blank W1 can be reduced). As a result, in the method for manufacturing a press-formed product according to the present embodiment, it is possible to improve the yield. In addition, in the method of manufacturing a press-formed product of the present embodiment, shallow drawing can be performed, so that the inflow of material can be reduced and the formability can be improved as compared with the conventional technology.

In addition, in the method of manufacturing a press-formed product of the present embodiment, a step-like bead portion Ws is formed in the vicinity of the end portion of the blank W1 in the holding step.

As a result, the size of the bead can be reduced as compared with the conventional arcuate or trapezoidal bead (the uneven bead Wb as shown in FIG. 8(b)). Therefore, in the method for manufacturing a press-formed product of the present embodiment, the length of the end portion of the blank W1 for forming the bead (length L2 in FIG. 5B) is reduced to improve the yield. can be done.

More specifically, in the conventional technique, the stepped portion 126 and the uneven bead Wb are provided, and the stepped portion 126 and the uneven bead Wb are used as hooks for the blank W1 in the drawing process (see FIG. 8B). ).

In contrast, in the method of manufacturing a press-formed product according to the present embodiment, it is not necessary to provide the stepped portion 126, and shallow drawing can be achieved. Further, by making the bead step-shaped (step-shaped bead portion Ws), even if the bead is made small, the blank W1 can be sufficiently hooked and stopped during the drawing process (positional deviation of the blank W1 can be can be suppressed). As a result, in the method of manufacturing a press-formed product of the present embodiment, the actual length of the blank W1 for forming the bead or forming the stepped portion 126 (for example, from the portion Y1 to the portion Y2 in FIG. 5B) is It becomes possible to reduce the distance L1) of the blank W1, and the yield can be improved.

<Second molding process>
After the first forming step, the blank W1 is conveyed to another working area and undergoes the second forming step. In the second forming step, the blank W1 formed into the predetermined shape in the first forming step is bent to form a negative angle portion.

More specifically, as shown in FIG. 6(a), in the second forming step, the stepped bead Ws formed near the end of the blank W1 is hooked on the step engaging portion 80 of the lower blank holder 76. In this state, the bending blade 70 moves in the approach direction X with respect to the blank W1. Further, as shown in FIGS. 6(b) and 7(a), the bending blade 70 pushes the blank W1 to form a hollow portion B. As shown in FIG.

That is, in the second forming step, the stepped bead portion Ws formed in the blank W1 is held (hooked) by the step engaging portion 80 of the lower blank holder 40, and the bending process is performed. In other words, the stepped bead portion Ws functions as a positioning portion of the blank W1 in the second forming process.

Thereby, the shape of the stepped bead portion Ws can be used for positioning the blank W1 in the bending process (second forming process).

Although the embodiment of the method for manufacturing a press-formed product of the present invention has been described above, the present invention is not limited to the above-described embodiment.

For example, in the press apparatus 10 described in the above-described embodiment, an example in which the die 20 is a movable die that can be raised and lowered and the punch 30 is a fixed die is shown. The apparatus is not limited to this, and the die 20 may be of a fixed type and the punch 30 of a movable type.

INDUSTRIAL APPLICATION This invention can be suitably employ|adopted as a method of manufacturing the press-formed product by drawing.

10 press device 20 die 30 punch 40 lower blank holder (first holding member)
41 die face 50 upper blank holder (second holding member)
60 step molding portion 61 lower side step molding portion (step molding portion)
62 upper side step forming part (step forming part)
70 Bending edge W1 Blank W2 Press-molded product W3 Part Ws Step-shaped bead

Claims (2)

A method for manufacturing a press-formed product by forming a blank using a press device,
The press-formed product has a substantially flat surface, and a concave portion forming a negative angle with respect to a direction intersecting the surface is formed in a portion that serves as an edge of the surface,
The press device
a die and a punch for pressing the blank;
a first holding member that supports the blank from below;
a second holding member that presses and holds the blank against the first holding member;
a holding step of holding a portion of the blank;
After the holding step, a first forming step of drawing the blank,
In the holding step, a portion of the blank is held between the first holding member and the second holding member,
The second holding member and the first holding member are provided with a step-shaped bead portion forming a step-shaped bead portion near the end of the blank,
A bending blade for bending the blank,
In the first forming step, the die is moved relative to the punch while the blank is held between the first holding member and the second holding member, and the punch and the die are separated from each other. The drawing is performed by pressing the blank between
After the first forming step, including a second forming step of bending the blank with the bending blade,
A method of manufacturing a press-formed product, wherein the step-like bead portion is formed in the holding step, and the step-like bead portion functions as a positioning portion of the blank in the second forming step. . The second holding member and the first holding member are provided with a step-shaped bead portion forming a step-shaped bead portion near the end of the blank,
2. The method of manufacturing a press-formed product according to claim 1, wherein said stepped bead portion is formed in said holding step.

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