KR20100076653A - Hydroforming system and method - Google Patents

Abstract

PURPOSE: A hydro-forming system and a method thereof are provided to mold a component having the large diameter change of a section through a hydroforming process. CONSTITUTION: A hydro-forming system comprises a hydroforming member(200) and a tube reducing member(100). The hydroforming member comprises a first cross-section(230), molds(210,220), and one or more second cross-sections(240). The first cross-section has minimum section diameter. The second cross-section is formed inside the mold. The tube reducing member reduces the tube area corresponding to the first cross section lower than the section diameter of the first cross section.

Description

Hydroforming System and Method

The present invention relates to a hydroforming system and method, and provides a hydroforming system and method capable of molding a product having a large change in size between a maximum cross section and a minimum cross section.

In general, hydro-forming is one of processing methods for expanding a pipe (ie, a tube) using hydraulic pressure. It is a technology for molding into the shape of a mold covering a tube by expanding a tube by applying a high pressure using a fluid inside the tube. Such hydroforming is currently mainly used in the automobile industry.

In the conventional method of making a part having a closed cross section, two parts of the upper and lower open sections are separately manufactured by press molding, and then a flange part is joined.

In contrast, the hydroforming process uses one tube to shape the product. Therefore, the effect of shortening the process and the number of molds and reducing the weight of the material can be obtained.

In this case, the tube is expanded and molded by the internal pressure, so that the tube is greatly influenced by the elongation of the tube material. This is limited in the ratio of the cross-sectional size of the initial tube to the cross-sectional size of the tube which is expanded after molding. The disadvantage is that the tube cannot be expanded indefinitely. That is, the tube expansion ratio is limited by the elongation of the tube material.

Of course, the portion near the end of the tube can be enlarged to some extent by expanding the tube end at the same time by pushing the end of the tube. In other words, the material is introduced into the area where the material becomes thin due to expansion, thereby delaying it.

Of course, to solve this, a tube having a large cross-sectional size can be used. However, the cross sectional diameter of the initial tube that can be used for hydropopping depends on the size of the minimum cross section of the mold for molding. This has the disadvantage of not using a tube with a large cross-sectional size.

Therefore, conventionally, when the size difference between the maximum cross-section and the minimum cross-section of the molded tube is large, there is a problem that cannot be formed through hydroforming. This made it impossible to mold the tube by hydroforming if the size of the largest cross section to be formed exceeded the limit of tube forming of the tube material.

1 and 2 is a cross-sectional conceptual view for explaining the disadvantages of the conventional hydroforming.

As shown in FIG. 1, an upper mold 10 and a lower mold 20 are provided. Here, the upper mold 10 and the lower mold 20 are coupled to each other to form a minimum cross section 31 and a maximum cross section 32.

Thus, the initial tube 1 before shaping | molding is arrange | positioned inside the minimum cross section 31 and the largest cross section 32. As shown in FIG. In this case, as described above, the cross-sectional size (ie, diameter) of the tube 1 is determined by the cross-sectional size (ie, cross-sectional diameter) of the minimum cross-section 310.

Subsequently, as shown in FIG. 2, a high pressure is applied to the inside of the tube 1 using a fluid to expand the tube 1. At this time, the expansion type of the tube 1 is determined by the upper and lower molds 10 and 20.

However, as shown in FIG. 2, if the cross-sectional size (ie diameter) of the largest cross-section 32 is larger than the maximum range in which the tube 1 can be expanded (ie, the largest expansion cross-section), FIG. 2. The problem occurs that the tube 1 is torn in the region of the largest cross-section 32, such as K region.

That is, for example, the cross-sectional diameter of the minimum cross-section 31 is 45mm, the cross-sectional diameter of the maximum cross-section 32 is 62.5mm as follows.

As mentioned above, the tube 1 should be a tube 1 having a cross-sectional diameter of about 42.5 mm. This is because a tube 1 of a cross section diameter smaller than the minimum cross section 31 must be used. In this case, when the diameter is larger than the above range, there is a problem that wrinkles occur in the center of the tube.

However, when using a tube 1 having a cross section diameter of 42.5 mm, the tube 1 should be expanded by 38.9% in the region of the maximum cross section diameter. However, less than 30% coverage can be achieved with tubes made of conventional steel or metal. Therefore, 38.9% expansion is practically impossible. Therefore, as shown in FIG. 2, the forming limit of the tube 1 is also reached, causing the tube 1 to burst.

Therefore, the present invention was derived to solve the above problems, while performing hydroforming using a tube larger than the cross-sectional diameter of the minimum cross-section, the tube area corresponding to the minimum cross-sectional area is condensed, and then hydroforming is performed. It is an object of the present invention to provide a hydroforming system and method capable of forming parts having large cross-sectional diameter changes.

According to the present invention, a tube is formed by using a first end portion having a minimum cross-sectional diameter, a mold portion provided with an at least one second end portion having a larger cross-sectional diameter than the first end portion, and hydraulic pressure. Hydroforming means for shaping to have at least one second cross-sectional shape, and condensing means for conduiting the tube region corresponding to the first cross-section to less than the cross-sectional diameter of the first cross-section using electromagnetic force. Provide a system.

The hydroforming means may include the mold part having the first end face portion and at least one second end face portion formed therein through a combination of an upper mold and a lower mold having the tube inserted therein and the uneven parts formed therein, respectively; It is preferable to include a hydraulic pressure supply device for supplying hydraulic pressure to the tube located inside.

It is effective that the maximum cross-sectional diameter of the at least one second cross-sectional portion is at least 30% larger than the minimum cross-sectional diameter of the first cross-sectional portion.

Preferably, the conduit means includes a shaping coil section surrounding the tube region corresponding to the first end section, and a power supply section for applying a pulsed induced current to the shaping coil.

The cross-sectional diameter of the tube may be larger than the minimum cross-sectional diameter of the first cross-section and smaller than the maximum cross-sectional diameter of the at least one second cross-section.

It is possible that the cross-sectional diameter of the tube is smaller in the range of 5-30% than the maximum cross-sectional diameter of the at least one second cross-section.

In addition, a hydroforming for forming a tube by using a first end portion having a minimum cross-sectional diameter and at least one second end portion having a larger cross-sectional diameter than the first cross-section is formed inside and a hydraulic pressure. A method, comprising: providing a tube having a cross-sectional diameter greater than a minimum cross-sectional diameter of the first cross-sectional portion, and conduiting the tube region corresponding to the first cross-sectional portion smaller than the minimum cross-sectional diameter of the first cross-sectional portion; And disposing the tube having the tube region corresponding to the first cross-section portion inside the mold portion, and supplying hydraulic pressure to the inside of the tube.

Condensing the tube region corresponding to the first cross-sectional portion smaller than the minimum cross-sectional diameter of the first cross-sectional portion is effective to generate an electromagnetic force in the tube region and to condense it with a repulsive force by the electromagnetic force.

As described above, according to the present invention, hydroforming may be performed by using a tube having an average cross-sectional diameter larger than the minimum cross-sectional diameter of the mold part by conduiting a partial region of the tube by using an electromagnetic force. According to the present invention, a component having a large change in cross-sectional diameter can be molded by a hydroforming method.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention in more detail. It will be apparent to those skilled in the art that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know. Like numbers refer to like elements in the figures.

3 is a conceptual diagram of a hydroforming system according to an embodiment of the present invention.

Referring to FIG. 3, the hydroforming system according to the present embodiment includes a first cross-section portion 230 having the smallest cross-sectional diameter and at least one second cross-sectional portion having a larger cross-sectional diameter than the first cross-sectional portion 230. Hydro-forming means 200 to expand the tube 300 to include the first and second cross-sectional portion 230, 240 shape by using the mold portion (210, 220) having the 240 and the hydraulic pressure, and the electromagnetic force It includes a shaft end 100 for condensing the tube region corresponding to the first end portion 230 smaller than the cross-sectional diameter of the first end portion 230. In this embodiment, the tube 300 having a larger cross-sectional diameter than the first cross-sectional portion 230 and a smaller cross-sectional diameter than the second cross-sectional portion 240 is used.

Hydroforming means 200 is a mold portion (210, 220) having a tube 300 is inserted into the inner side as shown in Figure 3 and having a first end portion 230 and at least one second end portion 240 In addition, a hydraulic supply device 250 for providing hydraulic pressure (or hydraulic pressure) to the tube 300 inserted into the mold parts 210 and 220 is provided.

The mold units 210 and 220 include an upper mold 210 and a lower mold 220. At this time, a plurality of upper unevenness (concave portion and protrusion) is formed on the lower side of the upper mold 210, and lower unevenness corresponding to the unevenness of the upper mold 210 is formed on the upper side of the lower mold 220. . In this case, the first end surface portion 230 and the at least one second end surface portion 240 are formed by the unevenness of the upper mold 210 and the lower mold 220.

Here, the plurality of second end surfaces 240 may be provided, and the cross-sectional diameters of the plurality of second end surfaces 240 may be different from each other. At this time, it is effective that the maximum cross-sectional diameter of the second cross-section portion 240 is greater than 30% than the cross-sectional diameter (ie, the minimum cross-sectional diameter) of the first cross-section portion 230. As described above, the ratio capable of expanding the tube 300 through the conventional hydroforming was 30% or less. However, in the present embodiment, even if the ratio of the first and second end portions 230.240 in the mold parts 210 and 220 by the shaft tube means 100 using electromagnetic force is greater than 30%, the hydroforming is performed. This is because the tube 300 can be expanded. In this case, it is preferable that the maximum cross-sectional diameter of the second cross-section portion 240 is 30 to 100% larger than the cross-sectional diameter (ie, the minimum cross-sectional diameter) of the first cross-section portion 230. Of course, even if more than 100% is possible, there is a possibility that deformation due to the increase of the tube 300 at the time of expansion and expansion of the shaft tube.

And, although not shown, a separate pressing means for pressing for coupling the upper mold 210 and the lower mold 220 may be further provided.

In addition, in the present embodiment, a fluid is injected into the tube 300 positioned between the upper mold 210 and the lower mold 220 to form the tube 300 in the shape of the first and second end portions 230 and 240. And a hydraulic pressure supply device 250 for molding. The hydraulic pressure supply device 250 preferably provides hydraulic pressure to the tube 300 at both ends of the tube 300.

In this embodiment, the tube 300 may be a tube 300 having a cross-sectional diameter larger than the cross-sectional diameter of the first cross-section portion 230. Through this, various hydroforming may be performed by performing expansion of a ratio smaller than the ratio of 30% or more.

To this end, the present embodiment includes a conduit means 100 for conduiting the region of the tube 300 corresponding to the first end portion 230.

As the conduit means 100, an electromagnetic field forming apparatus for forming a metal using electromagnetic force is used. The conduit means 100 includes a shaping coil part 110 surrounding the conduit area of the tube 300 (that is, a tube area corresponding to the first end surface part 230), and induces an induction current to the shaping coil 110. A power supply unit 120 is applied.

Here, when a pulse current passes through the shaping coil unit 110, a large magnetic field changes in the shaping coil unit 110 due to a change in current. At this time, a strong magnetic field is generated by the induced current in the adjacent metal (ie, the tube 300). Therefore, the magnetic force of the forming coil unit 110 and the magnetic force of the tube 300 act as a repulsive force with each other. Therefore, the tube 300 is pushed by the repulsive force and is molded. In other words, the region of the tube 300 issued by the repulsive force is condensed.

At this time, a strong repulsive force is required to axially tube the tube 300, which means that a large magnetic force is generated in the forming coil part 110. In the end, this means that the power supply unit 120 should provide high energy to the forming coil 110. That is, the power supply unit 120 should flow a high-capacity charge to the forming coil 110 in a short time. Therefore, it is effective to use a large capacity capacitor as the power supply unit 120.

Here, the applied energy required for molding is generally tens of kJ or more. In addition, since the molding is performed by the discharge of the stored charge amount of the power supply unit 120, the material motion of 0.1 to 100 m / s is possible, and most metal materials such as high strength steel, aluminum, and magnesium can be formed.

In addition, in order to push the tube 300, the shaping coil unit 110 should have sufficient strength. In addition, although not shown, a fixing body surrounding the shaping coil unit 110 may be provided.

Non-contact molding is possible by the shaft tube means using such an electromagnetic field. As a result, problems such as surface defects, lubrication, and abrasion of the material (ie, the tube 300) do not occur. In addition, various molding and local molding of the material are possible.

The cross-sectional diameter of the tube 300 can be made smaller than the cross-sectional diameter of the first cross-section portion 230 through the shaft tube means 100 as described above. This can improve the constraint of the cross-sectional diameter of the tube 300, which is the limit of the existing hydroforming. That is, as described in the background art, the cross-sectional diameter of the tube 300 used in the conventional hydroforming is the first end portion 230 of the mold portions 210 and 220, that is, the edge of the mold portions 210 and 220. It is determined by the small cross-sectional diameter. That is, a tube having a cross-sectional diameter smaller than the cross-sectional diameter of the first cross-sectional portion 230 should be used. This causes a problem that the tube 300 does not enter the mold parts 210 and 220 when the cross-sectional diameter of the tube 300 is larger than that of the first end surface 230.

However, in the present embodiment, it is possible to use the tube 300 having a larger cross-sectional diameter than the first end surface portion 230 by the shaft tube means 100. This causes the tube 300 to enter the mold parts 210 and 220 by condensing the region of the tube 300 corresponding to the first end surface portion 230 with the conduit means 100 using electromagnetic force. Through this, it is possible to solve the restrictions on the use of the tube 300 having a large cross-sectional diameter.

Hereinafter, a hydroforming method using the above-described hydroforming system will be described.

4 to 6 are cross-sectional views for explaining a hydroforming method according to an embodiment of the present invention. 7 is a tube picture of the tube tube by using an electromagnetic force according to an embodiment.

First, as shown in FIGS. 4 and 7, the tube 300 region corresponding to the first end face 230, which is the minimum cross-sectional diameter of the mold part 200, is reduced by using the shaft pipe means 100. The tube is made smaller in diameter than the cross-sectional diameter.

This allows the shaping coil 110 of the conduit means 100 to surround the region of the tube 300 (region A in FIG. 4) to be conduited. This may be performed by introducing the tube 300 into the inside of the forming coil 110 and adjusting the position of the tube 300.

Subsequently, the tube 300 is condensed by applying a pulse current to the forming coil 110 through the power supply 120, that is, the capacitor. As a result, as shown in FIG. 7, a tube 300 having a local region condensed may be manufactured.

Subsequently, as shown in FIG. 5, the tube 300 having the partial region condensed is positioned inside the mold parts 210 and 220 of the hydroforming means 200. In this case, the conduit tube 300 region is positioned in the first end surface region 230 of the mold portions 210 and 220.

Here, as shown in FIG. 5, the cross-sectional diameter T1 of the concentric tube 300 region is smaller than the cross-sectional diameter T2 of the first cross-sectional portion 230 of the mold parts 210 and 220. Do. In addition, the cross-sectional diameter T3 of the tube 300 except for the condensed region may be larger than the cross-sectional diameter T2 of the first cross-sectional part 230. In addition, it is effective that the cross-sectional diameter T3 of the tube 300 excluding the condensed area is smaller than the cross-sectional diameter T4 of the second cross-sectional part 240.

In the present embodiment, the cross-sectional diameter T4 (ie, the maximum cross-sectional diameter) of the second cross-section 240 is 30% or less than that of the cross-sectional diameter T3 of the tube 300 except for the condensed region. It is effective to use a tube 300 having a size. That is, it is preferable that the cross-sectional diameter T3 of the tube is smaller within the range of 5 to 30% than the maximum cross-sectional diameter T4 of the at least one second cross-section portion 240.

For example, when the cross-sectional diameter T2 of the first cross-sectional part 230 is 45 mm and the cross-sectional diameter T4 of the second cross-sectional part 240 is 62.5 mm, the tube 300 has a cross-section thereof. 50 mm diameter can be used. This was a tube that was not available in the background. However, in the present embodiment, the cross-sectional diameter T1 of the conduit region (ie, the region corresponding to the first end surface portion 230) of the 50 mm tube 300 is conduited to 42.5 mm. Through this, the 50mm tube 300 can also be used.

Subsequently, as shown in FIG. 6, the tube 300 is expanded by applying hydraulic pressure (ie, hydraulic pressure) to the inside of the tube 300. At this time, the tube 300 is not expanded indefinitely, it is expanded in accordance with the shape of the mold (210, 220) surrounding the outside. Through this, the tube 300 is formed into a shape having a cross section corresponding to the first cross section 230 and a cross section corresponding to the second cross section 240.

In this case, when the 50 mm tube 300 is used as in the previous example, even if the tube 300 is torn to fit the second end portion 240 (that is, the cross-sectional diameter is 62.5 mm), which is the largest expansion region, the tube 300 is torn or the like. Can be prevented. This is because when the 50 mm tube 300 is expanded to match the cross-sectional diameter T4 of the second end portion 240, the tube 300 may only be expanded to 30% or less, that is, only 25%. .

In the above description, the description has been made mainly on the case of having one second end portion 240. However, the present invention is not limited thereto, and second end faces 240 having different cross-sectional diameters may be formed in the mold parts 210 and 220.

In this case, the region of the tube 300 corresponding to the second end surface portion 240 except for the second end surface portion 240 having the largest cross-sectional diameter may be condensed by the conduit means 100 using electromagnetic force.

Although the invention has been described with reference to the accompanying drawings and the preferred embodiments described above, the invention is not limited thereto, but is defined by the claims that follow. Accordingly, one of ordinary skill in the art may variously modify and modify the present invention without departing from the spirit of the following claims.

1 and 2 is a cross-sectional conceptual view for explaining the disadvantages of the conventional hydroforming.

3 is a conceptual diagram of a hydroforming system according to an embodiment of the present invention.

4 to 6 are cross-sectional views for explaining a hydroforming method according to an embodiment of the present invention.

Figure 7 is a tube picture of the tube tube by using an electromagnetic force according to an embodiment.

<Explanation of symbols for the main parts of the drawings>

1, 300: tube 10: upper mold

20: lower mold 100: shaft pipe means

110: forming coil 120: power supply

200: hydroforming means 210: upper mold,

220: lower mold 230, 240: cross section

Claims (8)

The first cross-section having a minimum cross-sectional diameter, at least one second cross-sectional portion having a larger cross-sectional diameter than the first cross-section has a mold portion provided inside, and the tube is connected to the first cross-section and the at least one by using hydraulic pressure. Hydroforming means for shaping to have a second cross-sectional shape; And And conduit means for conduiting the tube region corresponding to the first cross-sectional portion to less than the cross-sectional diameter of the first cross-sectional portion using electromagnetic force. The method according to claim 1, wherein the hydroforming means, The mold portion having the first end face portion and the at least one second end face portion formed therein through the coupling of the upper mold and the lower mold having the tube inserted therein and the uneven portions respectively formed therein; And a hydraulic pressure supply device for supplying hydraulic pressure to the tube located inside the mold part. The method according to claim 1, And a maximum cross-sectional diameter of the at least one second cross-section is at least 30% greater (30-100%) than the minimum cross-sectional diameter of the first cross-section. The method according to claim 1, wherein the conduit means, A shaping coil part surrounding the tube region corresponding to the first end surface part; Hydroforming system including a power supply for applying a pulsed induction current to the forming coil. The method according to claim 1, And wherein the cross-sectional diameter of the tube is greater than the minimum cross-sectional diameter of the first cross-section and less than the maximum cross-sectional diameter of the at least one second cross-section. The method according to claim 5, And wherein the cross-sectional diameter of the tube is less than 5-30% less than the maximum cross-sectional diameter of the at least one second cross-section. In the hydroforming method of forming a tube by using a first end portion having a minimum cross-sectional diameter, at least one second end surface portion having a larger cross-sectional diameter than the first end portion and a mold portion provided inside and a hydraulic pressure, Providing a tube having a larger cross-sectional diameter than a minimum cross-sectional diameter of the first cross-section; Conduiting the tube region corresponding to the first cross-section to be smaller than the minimum cross-sectional diameter of the first cross-section; Disposing the tube in which the tube region corresponding to the first end surface portion is condensed inside the mold portion; And And supplying hydraulic pressure inside the tube. The method of claim 7, Axializing the tube region corresponding to the first cross-section is smaller than the minimum cross-sectional diameter of the first cross-section, And generating electromagnetic force in the tube region and causing the tube to retract with repulsive force caused by the electromagnetic force.

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