JPH06304677A - Recessed seat forming method - Google Patents

Abstract

PURPOSE:To provide a method to efficiently form a recessed seat part on a sheet like raw material. CONSTITUTION:A raw material 17 is mounted on the die surface of a lower die 25, the central part of a part to be formed to a recessed seat part of the raw material 17 is punched with a punching punch 19 of an upper die and a punching die 24 of the lower die 25 after descending the upper die 23 and clamping the peripheral part of the part to be formed of the raw material 17 between a pad 20 of the upper die 23 and the punch 21 of the lower die 25, next the recessed seat part is formed on the raw material by drawing th peripheral part of the part punched with a dending blade 18 of the upper die 23 and the punch 21 of the lower die 25. Therefore, the recessed seat part can be efficiently formed on the sheet like raw material with a single device, and because the wrinkles or the strain is not generated on the outer surface (design surface) of the article, the article of the excellent appearance and the quality can be easily obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recess seat forming method, and more particularly to a recess seat forming method capable of efficiently forming a recess seat portion on a thin plate-shaped material by a single apparatus.

[0002]

2. Description of the Related Art In order to efficiently produce various structural materials having various shapes, such as outer panels of automobiles, mechanical device parts, building materials, etc., a processing method using a molding die such as drawing or bending is widely used. ing.

A so-called recessed seat forming method for forming a recessed portion having a predetermined shape, that is, a recessed seat on a flat surface of a thin plate-shaped material is processed by forming the recessed seat on the thin plate-shaped material in one step. Since wrinkles and distortions are likely to occur on the outer surface (design surface) of the product due to the insufficient flow of the material involved, conventionally there are two steps, a drawing process using a drawing die and a bending process using a bending die. Was done in a way that consisted of

An example of a conventional recess seat forming method will be described with reference to the drawings. FIG. 3 is a diagram for explaining a drawing process in the conventional recess seat forming method. In the drawing process, the punch 1 and the die 2 are used to draw the thin plate-shaped material 3 into a predetermined shape. At this time, the end of the material 3 is clamped and fixed by the die 2 and the pressing member 4.

FIG. 4 is an enlarged view of a portion A surrounded by a broken line in FIG.
Shown in. In FIG. 4, the solid line portion of the material 3 shows the shape processed in the drawing process. The part indicated by the broken line of the material 3 shows the final product shape 5 of the material 3 to be processed. If an attempt is made to draw the final product shape 5 at a time in the drawing process, a product crack will occur due to the local elongation of the material 3 on the curved surface portion 6 and the curved surface portion 7 in the shape at the previous stage, so that the final product shape 5 The shape of the curved surface is smaller than that shown by the solid line.

FIG. 5 is a view for explaining a bending process in the conventional recess seat forming method. In the bending process, the material 9 that has been previously drawn is formed into a product shape by using a die 9 having a bending blade 8 for restrike, a punch 10 and a pad 11 (holding and fixing the peripheral portion of the processed portion). Bend.

An enlarged view of a portion B surrounded by a broken line in FIG. 5 is shown in FIG.
Shown in. The portion indicated by the broken line of the material 3 shows the drawn shape 12. The drawing shape 12 is bent into a final product shape by using the curved blade 8, the punch 10 and the pad 11.

In addition to the two-step method of the drawing process using the drawing die and the bending process using the bending die,
As a molding method for obtaining a product having excellent appearance quality, a press working method using a molding die in which a recess is formed in one die is proposed in recent years, for example, as disclosed in JP-A-4-167930. Has been done.

Based on FIGS. 7 and 8, Japanese Patent Laid-Open No. 4-16
The pressing method described in Japanese Patent No. 7930 will be described. As shown in FIG. 7, the upper mold 13 and the recess 14 (for example,
When the thin plate-shaped material 16 is pressed by using the lower mold 15 in which a predetermined number is provided at a place where wrinkles may occur, as shown in FIG. Since it enters the place 14, it is possible to prevent wrinkles of the material 16 after molding and product cracking.

[0010]

However, the conventional recess seat forming method having two steps of the drawing process using the drawing die and the bending process using the bending die has the following problems. 1) Problems in drawing When the concave seat part is preformed, the material is constrained due to the familiarity (contact resistance) caused by contact with the lower die punch, so that when the concave seat part is formed, Not only the material of the seat portion extends, but also the material is drawn into the recess seat portion from the design surface side near the recess seat portion, for example. For this reason, a difference occurs in the flow direction of the material in the recessed seat portion and its vicinity, and for example, wrinkles due to excess material occur on the design surface side of the four corners of the recessed seat portion after molding, causing surface distortion. 2) Problems in curved molds In order to mold the recessed seat part preformed by the drawing mold to the final product shape, the wrist-like molding with curved blades is performed.
Since the material released from the drawing die is deformed according to the shape of the lower die punch of the drawing die, the convex and concave parts of the preformed material and the mold surface of the lower die punch of the bending die are newly formed. It is necessary to match and. In addition, the curved surface formed by the drawing die is hard to be formed because it has rigidity. Therefore, even if the peripheral portion of the portion to be processed is sandwiched and fixed by the pad and the lower die punch, the above-mentioned portion is formed by the curved blade. When the process starts, surface distortion is likely to occur again on the design surface of the outer plate.

With respect to the surface distortion caused by the above 1) and 2), the clearance between the upper mold and the lower mold is adjusted, the pad pressing surface is adjusted, and the punch curvature is changed (for example, overcrown and undercrown). It is necessary to take measures such as

On the other hand, even if the press working method described in Japanese Patent Laid-Open No. 4-167930 is applied to the recess seat forming, there is a possibility that the recess seat forming can be performed by a single device, but the material It is not possible to completely prevent the deformation of the material due to the local elongation of the material (formation of the convex portion on the material surface due to the material entering into the recess), and for example, post-treatment may be required.

The present invention is intended to solve the above-mentioned problems of the prior art. The object of the present invention is that it can be efficiently carried out by a single device, and the design surface of the material after processing can be improved. It is an object of the present invention to provide a recessed seat forming method that does not cause wrinkles or distortions.

[0014]

That is, a concave seat forming method according to the present invention comprises a curved blade, a punch for punching holes, an upper die having a pad and a pressing means for pushing the pad against a punch of a lower die, and a curved blade. A concave seat forming method for forming a concave seat portion on a thin plate-like material by using a punch forming a pair with a pad and a punch forming a pair of punches and a lower die including a pair of punching dies. Place it on the die surface of the die, then lower the upper die to sandwich the peripheral part of the material to be formed with the upper die pad and the lower die punch, and then punch the upper die punch and the lower die. Using the punching die, punch out the central part of the part where the concave seat part of the material should be formed, and then draw the peripheral part of the part punched with the upper mold blade and the punch of the lower mold It is characterized in that the seat is molded.

In the method of the present invention, as means for holding the peripheral portion of the material to be molded by the upper die pad and the lower die punch, a suitable conventional pressing means such as a pressure cylinder or an elastic means, for example, is used. A spring, rubber (for example, urethane rubber) or the like can be used. The case where a pressure cylinder is used as the pressing means will be described in more detail as an example. In this case, the arrangement and number of the pressure cylinders are appropriately selected according to the size and shape of the recessed seat portion to be molded. For example, in the case of a substantially rectangular recessed seat portion, it is advisable to arrange the pressure cylinders near the four corners of the recessed seat portion to be molded. Also, the number of pressurizing cylinders should be increased as much as possible due to the structure of the device. In addition,
As the driving means of the pressurizing cylinder, conventional means such as hydraulic pressure, air pressure, nitrogen pressure or the like can be used.

The punching punch of the upper die and the punching die of the lower die are formed by punching so that a product having a desired property can be obtained according to the size and shape of the concave seat portion to be formed. Select a shape. Further, the punching punch of the upper die and the punching die of the lower die are appropriately arranged so that the central portion of the portion where the concave seat portion of the material is to be formed can be punched.

The size and shape of the curved blade of the upper die are selected so that a predetermined concave seat portion can be formed in the material by drawing the peripheral portion of the punched portion together with the punch of the lower die.

The upper mold and the lower mold can be driven by automatic control using a computer, for example.

The thin plate-shaped material for forming the recessed seat may be a conventional press material which can be plastically deformed, such as a steel plate.

[0020]

[Operation] Prior to drawing, the central part of the part where the concave seat of the material is to be formed is punched out, so the flow of material during drawing is good, and wrinkles and distortion on the outer surface (design surface) of the product It never happens.

[0021]

The present invention will be described in more detail with reference to the following examples.

FIG. 1 shows a state in which a thin plate-shaped material 17 (steel plate) is placed on the mold surface of a lower mold in the method of the present invention.
As the material 17, a material other than the recessed seat portion may be molded in advance by a drawing die. The apparatus used in the method of the present invention comprises a curved blade 18, a punch 19 for punching, an upper die 23 provided with a pad 20 and a pressure cylinder 22 for pressing the pad 20 against a punch 21 of a lower die, and the curved blade 18 And a lower die 25 having a punch 21 paired with the pad 20 and a punching die 19 paired with the punching punch 19.

The curved blade 18 and the punch 21 are processed so as to form a concave seat shape on the material 17. A punch punch 19 is built in the center of the annular convex portion of the curved blade 18, and a punch die 24 is provided in the center of the recess of the punch 21.
Is built in. The pad 20 can be moved up and down by a pressure cylinder 22.

The pressurizing cylinder 22 is driven by changing the injection pressure of nitrogen, and the material 17 can be clamped and fixed by the pad 20 and the punch 21 with a predetermined restraining force. During molding, if the nitrogen injection pressure of the pressurizing cylinder 22 is changed while the material 17 is clamped and fixed, the restraining force of the material 17 (pressure per unit area of the outer periphery of the concave seat to be formed) is changed as desired. Can be made.

In this example, since the concave seats to be formed are substantially rectangular, one pressure cylinder 22 is arranged near each of the four corners of the concave seats to be formed.

Next, when the upper die 23 is lowered as shown in FIG. 2, the pad 20 first comes into contact with the design surface of the material 17, and the material 17 is sandwiched and fixed by the pad 20 and the punch 21.
Next, the curved blade 18 of the upper die 23 and the punching punch 19 are lowered to move the blank 17 with the punching punch 19 and the punching die 24.
A punching piece 26 having a perfect circle shape is punched out from. In this case, if the punching shape is, for example, a shape with corners (for example, a rectangular shape), defects such as cracks and elongation will occur at the corners of the punching part and the vicinity thereof when forming the recessed seat. The end portion of the flange portion formed by punching as a perfect circle is made uniform in elongation, and defects such as cracking and distortion are prevented.

Further, the curved blade 18 is lowered, and the material 17 in the peripheral portion of the punched portion is formed into a concave seat shape by the curved blade 18 and the punch 21. In FIG. 2, the broken line portion of the material 17 shows a state in which the concave seat portion is being formed.

When forming the recessed seat portion, the peripheral portion (design surface side) of the portion of the material 17 where the recessed seat portion is to be formed is clamped and fixed by the pad 20 and the punch 21, so that it is formed by punching. Curved blade 1 in the form of flowing the material 17 toward the hole
Since the molding proceeds until 8 reaches the bottom dead center, defects such as wrinkles and distortion do not occur in the peripheral portion of the concave seat portion of the product.

[0029]

As described above, in the concave seat forming method of the present invention, the concave seat portion of the material should be formed by the punching punch of the upper die and the punching die of the lower die prior to forming the concave seat portion. The central part of the part is punched, and then the peripheral part of the punched part is drawn by the upper mold blade and the punch of the lower mold to form the concave seat part in the material, so the material is punched during drawing. Since it flows toward the generated holes, the flow of the material during drawing is good, and wrinkles and distortion do not occur on the outer surface (design surface) of the product, and it is possible to easily obtain a product with excellent appearance quality. .

Further, according to the method of the present invention, it is possible to continuously and efficiently perform the blanking process and the drawing process of the material by using a single molding apparatus, which is excellent in productivity.

Further, in the method of the present invention, since wrinkles and distortions do not occur on the product design surface as described above, the wrinkles on the product design surface which were necessary when the conventional concave seat forming method was used. Since there is no need to take measures to prevent distortion and to remove wrinkles and distortions, the molding process can be simplified, so that the costs associated with molding can be reduced as a whole.

Further, the method of the present invention requires only a single molding apparatus, and compared with the conventional two-step method of the drawing process using a drawing die and the bending process using a bending die, Since the number is reduced, the facility cost can be reduced.

Further, since it is only necessary to consider a single molding device in order to prevent wrinkles and distortion from occurring on the product design surface when forming concave seats of materials of various sizes and shapes, it is necessary to take measures in the production preparation stage. Since the lead time can be shortened, it is possible to supply high quality products to the market at an early stage.

[Brief description of drawings]

FIG. 1 is a view showing a state in which a thin plate-shaped material is placed on a mold surface of a lower mold in the concave seat molding method of the present invention.

FIG. 2 is a diagram for explaining a punching process and a drawing process of a thin plate-shaped material in the recess seat forming method of the present invention.

FIG. 3 is a diagram for explaining a drawing process in a conventional recess seat forming method.

FIG. 4 is an enlarged view of a portion A surrounded by a broken line in FIG.

FIG. 5 is a diagram for explaining a bending process in a conventional recess seat forming method.

6 is an enlarged view of a B portion surrounded by a broken line in FIG.

FIG. 7 is a diagram showing a state in which a thin plate-shaped material is placed on the mold surface of a lower mold in the conventional pressing method.

FIG. 8 is a diagram showing a state in which a thin plate-shaped material placed on a mold surface of a lower mold is then pressed by a conventional pressing method.

[Explanation of symbols]

 1,10,21 Punch 2,9 Dies 3,16,17 Material 4 Holding member 5 Final product shape 6,7 Curved part 8,18 Curved blade 11,20 Pad 12 Drawing shape 13,23 Upper mold 14 Recess 15 , 25 Lower die 19 Hole punch 22 Pressure cylinder 24 Hole die 26 Stamping pieces A, B Part surrounded by broken line

Claims (1)

[Claims] 1. An upper die having a curved blade, a punch punch, a pad and a pressing means for pushing the pad against a lower punch, and a pair of the punch and punch punch which are paired with the curved blade and the pad. It is a concave seat forming method for forming a concave seat portion on a thin plate-shaped material by using a lower mold equipped with a punching die, and the material is placed on the mold surface of the lower mold, and then the upper mold is placed. After lowering and clamping the peripheral part of the material to be molded with the upper mold pad and the lower mold punch, the concave seat part of the material should be molded by the upper mold punch and the lower mold punch. A recess seat forming method characterized by forming a recess seat part in a material by punching the central part of the part, and then drawing the peripheral part of the punched part with a curved blade of the upper die and a punch of the lower die. .