KR20220157674A - Composite Press Mold Device - Google Patents

Abstract

The present invention relates to a composite molding press apparatus capable of preventing wrinkles, cracks, and spring back during high-strength steel press work. The molding press apparatus for pressing a steel plate material into a predetermined shape of a molded product comprises a lower mold provided in the lower part of the press apparatus and including a draw punch; an upper mold provided above the lower mold and including a draw cavity; and a holding pad provided inside the draw cavity and pressing the upper surface of the steel plate material.

Description

Composite Press Mold Device {Composite Press Mold Device}

The present invention relates to a press device, and more particularly, to a composite mold press device capable of preventing wrinkles, cracks, and spring back during high-strength steel sheet press work.

The press process, which processes parts using steel plate materials, involves drawing, which involves mounting a mold on the press and pressurizing it into a predetermined shape in an up and down direction, trimming, which cuts out unnecessary parts of the finished product, and additional shapes. It is common to go through the process of making flanging and piercing processing holes.

The above processes are collectively referred to as a stamping process, and a metal molding is typically completed through an average of four processes of forming, cutting, bending, and hole processing. Among the above processes, the drawing process usually refers to a process of placing a flat steel plate material on the upper surface of the blank holder or on a die and pressing it into a predetermined shape through a punch, and the die may be disposed on the upper or lower side.

In the mold press device used in the drawing process, a blank holder is installed along the edge of a lower mold in which a draw punch is formed, a draw cavity having a shape corresponding to the draw punch, and an upper die in which a binder is formed around the draw cavity. In a state in which the steel plate material located between the upper and lower molds is bound with a constant pressure between the blank holder and the binder by lowering the upper mold, the upper mold is lowered to the bottom dead center, so that the steel plate material is molded into a molding having a predetermined shape.

Compared to general forming mold devices, the above conventional mold press device for drawing is formed in a state in which the steel plate material is fixed by a blank holder and a binder, so even if it is molded into a molded product with a complex shape, the phenomenon of wrinkles in the molded product can be prevented. However, in recent years, as the supply of high-strength steel sheets increases, the number of cases in which molding defects occur in the conventional mold press apparatus for drawing has increased.

Looking at the above molding defects in more detail, when a product is formed by a drawing method using a high-strength steel plate material, the high-strength steel plate material located on the upper surface of the blank holder is in contact with the binder of the die descending from the upper mold side, and the lower surface of the high-strength steel plate material Some of them come into contact with the upper surface of the draw punch, and the material flows into the draw cavity. At this time, pressure can be applied to the upper surface of the material flowing into the draw cavity, but wrinkles, cracks and spring back occur due to the high yield point, which is a mechanical characteristic of high tensile steel. this happens

The spring back is caused by a difference in the thickness direction and in-plane stress of the area to be bent even when a force below or above the elastic limit is applied in the process of forming by bending the steel plate material. Since it is difficult to completely remove the elasticity of the plate itself, it refers to a phenomenon in which the steel plate material tries to recover to its original state, and has a great adverse effect on the dimensional accuracy and shape freezing of the molded product.

In particular, when there is a large difference in pressure between the upper and lower surfaces of the part in contact with the draw punch in the high-strength steel sheet material, wrinkles, cracks, and springback phenomena of the molded product tend to increase more. pointed out as a problem.

Republic of Korea Patent Registration No. 10-1582916

In order to solve the above problems, the present invention is a composite that can prevent wrinkles, cracks, and spring back occurring during high-tensile steel sheet press work by minimizing the difference in pressure between the upper and lower surfaces of the high-strength steel sheet material in contact with the draw punch. It is intended to provide a mold press device.

The present invention relates to a mold press device for press-processing a steel sheet material into a molding having a predetermined shape, wherein a lower mold is formed under the press device and includes a draw punch, and an upper mold is formed on the top of the lower die and includes a draw cavity. It is characterized in that it comprises a mold and a holding pad configured in the inner direction of the draw cavity to press the upper surface of the steel plate material.

The present invention presses the edges of the high-strength steel sheet material in the upper and lower directions by the action of the blank holder and the binder, and presses the upper surface of the corresponding steel sheet material with a holding pad when the draw punch presses the lower surface of the steel sheet material, It has the effect of minimizing the pressure difference between the upper and lower surfaces of the steel plate material.

In addition, the present invention has an effect of preventing excessive wrinkles, cracks, and spring back generated in a molded article by minimizing the difference in pressure between the upper and lower surfaces of the steel plate material during the high-strength steel plate press operation as described above.

1 is an exemplary view showing the overall configuration of a composite mold press device according to the present invention.
Figure 2 is an exemplary view showing a state in which the upper mold is partially lowered in the composite mold press device according to the present invention.
Figure 3 is an exemplary view showing a state in which the upper mold is lowered to the bottom dead center in the composite mold press device according to the present invention.

Specific details for solving the problems according to the present invention will be described in detail together with the accompanying drawings. However, the accompanying drawings may be exaggerated, omitted, or schematically illustrated for convenience of description of essential parts, and the terms and names used in the description are implicitly defined by the shape, action, role, etc. of the configuration rather than the dictionary meaning. The description of the direction is determined based on the direction first presented from the initially presented drawing, and the description of the position is determined based on the middle of each configuration or the center of the circle. In addition, detailed descriptions of pre-registered known technologies and conventional technologies may obscure the gist, so they are omitted or replaced with simple codes or names.

In addition, the specific structure, shape, shape, arrangement, size, etc. of the configuration that can be identified through the drawings, the operation of the configuration that can be inferred through the drawings and the resulting action and effect, etc. may obscure the point, so detailed descriptions will be omitted. Bolts, welds, holes, etc. applied for coupling between components may obscure the point and may be omitted from the drawings.

1 is an exemplary view showing the overall configuration of a composite mold press device according to the present invention. Referring to FIG. 1 , the composite mold press device according to the present invention includes a lower mold 100, an upper mold 200, and a holding pad 300. In the following description, since the rest of the detailed configuration of the mold apparatus for press-working the raw material 400 for steel is a well-known technique, the description thereof will be omitted.

The lower mold 100 includes a draw punch 110 corresponding to the shape of the lower surface of the molded object and a blank holder 120 arranged at a predetermined distance from the draw punch 110 and configured to surround the draw punch 110. The blank holder 120 further includes a blank holder spring 121 formed of pneumatic or hydraulic pressure or a metal material.

The draw punch 110 is fixed to the lower mold 100 and flows into the draw cavity 210 of the upper mold 200 when the upper mold 200 descends, and the draw punch 110 and the draw cavity 210 ) The steel plate raw material 400 is placed between and press-formed.

The blank holder 120 presses the edge of the steel plate material 400 together with the binder 220 of the upper mold 200 according to the descent of the upper mold 200 in a state where the blank holder spring 121 is configured at the bottom, , As the upper mold 200 descends, the blank holder spring 121 contracts and presses the steel plate material 400 with a constant pressure.

The upper mold 200 includes a draw cavity 210 formed in a shape corresponding to the draw punch 110, a binder 220 configured to surround the circumference of the draw cavity 210, and the draw cavity 210. It includes a pad groove 230 formed in an upward direction from the upper end.

The draw cavity 210 has a shape corresponding to the shape of the upper surface of the molded object, and is configured inside the upper mold and disposed in the upper direction of the draw punch 110. The binder 220 is formed to surround the circumference of the draw cavity 210 in the upper mold 200 and is disposed in the upper direction of the blank holder 120 . That is, when the upper mold 200 descends, the binder 220 and the blank holder 120 pressurize the material steel sheet 400 in the upper and lower directions to firmly fix the material steel sheet 400 .

The pad groove 230 is formed inside the prize mold 200 in an upward direction from the upper end of the draw cavity 210 . The pad groove 230 has a shape in which a holding pad 300 to be described below is accommodated therein, and a pad control unit 310 to be described below is disposed above the pad groove 230 .

The holding pad 300 is formed inside the draw cavity 210 and protrudes further downward from the lower end of the draw cavity 210 . The holding pad 300 is coupled to the upper pad control unit 310 to apply a predetermined pressure downward. The pad control unit 310 may be formed of pneumatic or hydraulic pressure or a metal spring.

Figure 2 is an exemplary view showing a state in which the upper mold is partially lowered in the composite mold press apparatus according to the present invention, Figure 3 is an exemplary view showing a state in which the upper mold is lowered to the bottom dead center in the composite mold press apparatus according to the present invention to be. Since Figure 1 shows a state before the upper mold is lowered in the composite mold press device according to the present invention, the operation of the composite mold press device according to the present invention and its actions are as follows with reference to FIGS. 1 to 3 .

As shown in FIG. 1, the steel plate material 400 is seated in the blank holder 120 of the lower mold 100, and the blank holder 120 and the draw punch 110 are placed in the lower direction of the steel plate material 400 is placed Since the upper mold 200 has not started to descend, the steel plate raw material 400 and the upper mold 200 are not yet in contact.

The steel plate material 400 is a high-strength steel plate having higher strength than a general steel plate of the same thickness, and has a tensile strength of 40 to 50 kg/mm² or more, and 100 kg for automobile body parts using collision and safety structures. /mm² or more Ultra High Strength Steel is used.

Referring to FIG. 2 , while the upper mold 200 descends, the draw cavity 210 moves in the direction of the draw punch 110 and the binder 220 moves in the direction of the blank holder 120, and thus the holding pad 300 It also moves in the direction of the draw punch 110. Thereafter, the binder 220 and the blank holder 120 press the edges of the steel sheet material 400, and the draw punch 110 and the holding pad 300 press the center of the steel sheet material 400 to form the steel sheet material 400. ) is started. The upper mold 200 is further lowered, the binder 220 and the blank holder 120 maintain the pressure of the steel plate material 400, and the holding pad 300 maintains the position to apply pressure to the steel plate material 400 keep

That is, in a situation where the upper mold 200 is lowered, and thus the draw punch 110 is connected to the inside of the draw cavity 210 and press processing of the steel plate material 400 is being performed, the holding pad 300 is the steel plate material The pressure imbalance situation in which pressure is applied only to the lower surface of the steel sheet material 400 due to the draw punch 110 during press processing is eliminated by pressing the central upper surface of the steel sheet 400 with a constant pressure.

As shown in FIG. 3 , the upper mold 200 descends to the bottom dead center, the holding pad 300 remains pressed, and the blank holder 120 and the binder 220 remain pressed. That is, until the press working of the steel sheet material 400 is completed, the holding pad 300 and the draw punch 110 maintain a balance in the upward and downward pressure, and the blank holder 120 and the upper, The downward pressure or balance is maintained to prevent excessive wrinkles, cracks, and spring back caused by a difference in pressure in the upward and downward directions during press processing of the steel sheet material 400 .

The above present invention is a drawing of the configuration of the present invention and specific components included in the configuration to help the understanding of the principle of the configuration to be pursued by the present invention and the principle, and explained based on the drawing, The structure, form, shape, arrangement, direction, and quantity of the components included in the present invention and their specific components are determined in consideration of the principle to be pursued, and these may be variously changed as needed. The configuration and specific components thereof presented in the present invention exemplify the effect that a person skilled in the art would like to obtain from the present invention and which principle is most preferable to apply in order to obtain a better effect from the effect. it did Accordingly, the present invention is most preferably completed by including all of the above-described configurations, but it is possible to complete the present invention by selecting or excluding some of the above-described configurations according to cost reduction, manufacturing convenience, environmental conditions, or needs. In addition, one or more components may be separated and merged with other components to complete the configuration. In addition, each configuration described above may be independently applied to other technical fields other than this technical field in consideration of principles, uses, functions, roles, actions, and effects. Based on this, the scope of the present invention can be claimed in the order in which the scope of rights is wide by specifying the scope of the claims of the present invention as follows.

100: lower mold 110: draw punch
120: blank holder 121: blank holder spring
200: prize mold 210: draw cavity
220: binder 230: pad groove
300: holding pad 310: pad control unit
400: steel plate material

Claims (2)

In the mold press device for press-working the steel plate raw material 400 into a molding having a predetermined shape,
A lower mold 100 configured under the press device and including a draw punch 110;
An upper mold 200 configured on an upper part of the lower mold 100 and including a draw cavity 210;
Composite mold press device, characterized in that it comprises a holding pad 300 configured in the draw cavity 210 in the inner direction to press the upper surface of the steel plate material 400.
The method of claim 1,
The lower mold 100 includes a draw punch 110 corresponding to the shape of the molding and a blank holder 120 disposed at a predetermined distance from the draw punch 110 and configured to surround the draw punch 110,
The upper mold 200 is composed of a draw cavity 210 formed in a shape corresponding to the draw punch 110 and surrounding the circumference of the draw cavity 210, corresponding to the blank holder 120 in the vertical direction. It includes a binder 220 formed at a location and a pad groove 230 formed upward from the upper end of the draw cavity 210,
The holding pad 300 further includes a pad control unit 310, wherein the holding pad 300 contacts the lower surface of the steel plate material 400 with the draw punch 110 so that the upper surface of the steel plate material 400 forms a draw cavity ( 210), it is configured to contact the upper surface of the steel plate material 400 to minimize the pressure difference between the upper and lower surfaces of the steel plate material 400, and the pad control unit 310 is inside the pad groove 230 Composite mold press device, characterized in that configured to be arranged to apply an appropriate pressure to the holding pad (300).

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