WO2015130078A1 - Pressing unit-equipped hot stamping molding apparatus and molding method using same - Google Patents

Abstract

The present invention relates to a pressing unit-equipped hot stamping molding apparatus, and a molding method by means of same, and the purpose of the present invention is to provide a pressing unit-equipped hot stamping molding apparatus capable of increasing the effectiveness of thermal conductivity when press-molding by pressing with an upper mold by installing a pressing unit for pressing and supporting a workpiece in between a low pad and a lower plate of a lower mold to support and press-adhere the workpiece to the upper mold and the lower mold by means of the pressing unit, and a molding method by means of the pressing unit-equipped hot stamping molding apparatus. Disclosed is a hot stamping molding apparatus for molding a workpiece into a molded product by means of the upper mold driven by a press mechanism and provided with a cooling line in the interior, and the lower mold installed on the lower plate so as to correspond to the upper mold and provided with a cooling line in the interior, the lower mold comprising: a low pad which comes in contact with a workpiece to mold same, and which is provided with a cooling line in the interior thereof; a first low die on which the low pad is seated to be supported; a second low die fixed on the lower plate so as to be positioned below the first low die; and a pressing unit, installed so as to be positioned between the first low die and the second low die, for supporting one side of the low pad and pressing same in the molding direction. Thus when a workpiece is hot formed, the workpiece is in close and uniform contact with the upper and lower molds due to the pressing unit to increase cooling effectiveness.

Description

Hot stamping forming apparatus having a pressurizing portion and forming method using the same

The present invention relates to a hot stamping molding apparatus having a pressurizing portion and a molding method using the same, wherein a lower portion of the hot stamping molding apparatus is provided with a pressurizing portion, and the low pad of the lower mold in the upper mold direction during hot stamping press molding. The present invention relates to a hot stamping molding apparatus and a molding method using the same by supporting and pressing the material and the upper mold and the lower mold to make close contact with each other, thereby increasing the heat transfer efficiency of the material and improving the cooling efficiency.

In general, a method of manufacturing a molded body by heating a boron steel material above the Ac3 temperature and quenching it in a closed mold immediately after high temperature molding is called a hot press method. This method is called a hot stamping method. It is also called press hardening method because high strength martensite structure appears in steel sheet.

In this hot stamping method, the boron steel material, which is hardened by adding B, Mo, Cr, and the like, is fully austenitized by heating to a high temperature of about 900 ° C. which is higher than the Ac3 transformation point, and then the steel sheet is It is a method for manufacturing high strength products by martensite through rapid cooling while hot forming into product shape at once, and is widely used to manufacture high strength automobile body parts with tensile strength of 1470 MPa.

In the press hardening process using the hot stamping method, the wound steel sheet C is cut into a predetermined size by a cutting facility, and the cut sheet is charged into a heating facility such as an oven or a furnace. After that, the steel plate is heated to a temperature above the Ac3 transformation point so that the steel plate is completely austenite, and then the plate is immediately transferred to the mold of the press to be formed by stamping, and the plate is defined inside the closed mold. It is designed to transform into high strength martensite by quenching using a cooling system under pressure.

At this time, the steel sheet is supplied in a sheet form in a blanking state in advance, and is heated in a box furnace to be heated after reaching a target temperature for about 5 minutes and then pressing within 10 seconds by a transfer robot. Pre-process rapidly injected into the device, the main process (press molding-mold cooling) and the post process (trimming, piercing) process.

Since the steel sheet manufactured by the hot stamping process has a martensite structure, the steel sheet has a high tensile strength of 1500 MPa or more, so that the car body can be formed in a thin thickness, so that the car body can be reduced in weight and formed under high temperature conditions. As a result, it has a high elongation rate, and the spring back phenomenon is prevented while cooling is performed at the same time as the sheet is constrained inside the closed mold, thereby improving the dimensional accuracy and thus having high formability. Since there is little springback, it can contribute to the ultra-high strength demanding parts that are difficult to form and contribute to the weight reduction of automobiles.

Conventional hot press molding apparatus is configured to be formed between the upper and lower molds having a molding area of the shape to be heated to be molded, and to be formed by applying mechanical force, the molded object is the upper and lower parts In order to perform the cooling of the molded object immediately in the state where the molding is made by pressurization of the mold, a cooling passage through which a refrigerant flows is provided inside the mold.

The conventional hot press forming apparatus configured as described above is an indirect cooling method in which cooling occurs due to contact between the upper and lower molds formed with the cooling flow path and the object to be formed, and the contact surfaces of the upper and lower molds with the cooling flow path formed and the molding are uniform. Only then can efficient cooling be carried out and control of the cooling temperature for the entire area of the molding can be achieved.

However, the conventional hot press forming apparatus is formed by pressurization of the press apparatus connected to the upper mold, so that the contact between the mold and the molding is not smooth due to the thickness of the material and the combination of the mold itself. In this case, when the gap is generated, the cooling of the molding is not made uniformly, so that the physical properties of the entire region of the molding are changed, making it difficult to produce a product having a uniform strength or the required strength. There was a problem.

Of course, in order to solve this problem, it is necessary to design the mold so that the contact is made correctly, but it is difficult to manufacture the mold itself as well as such a design, and even if the mold is manufactured so that the contact is made correctly, the interface between the upper and lower molds Due to the problem that the shape is formed in the molded object, there is a problem in that it is difficult to produce the physical properties of the molding uniformly.

In addition, there is a method of controlling the pressure between the mold and the molded object in the press apparatus so that there is no gap between the mold and the molded object, but domestic hot press processing is performed by using a cold press method. In order to control the pressure in the press apparatus, since it is necessary to change the entire mold and equipment structure, there is a problem that can not be practically applied due to the huge increase in equipment costs.

(Prior art document)

(Patent Document 1) Registered Patent Publication No. 10-0951042 (2010.03.26)

(Patent Document 2) Registered Patent Publication No. 10-1225433 (January 16, 2013)

(Patent Document 3) Publication No. 10-2011-0081706 (July 14, 2011)

(Patent Document 4) Publication No. 10-2013-0015633 (2013.02.14)

An object of the present invention is to provide a pressurizing part for pressurizing and supporting the material between the lower pad and the lower plate of the lower mold, and during press forming of the upper mold by the press, the press is attached to the upper mold and the lower mold to support and press the material to the upper mold and the lower mold. It is to provide a hot stamping molding apparatus having a pressurizing portion that can increase the and a molding method using the same.

The present invention is a hot stamping molding for forming a material into a molding by an upper mold driven by a press machine and having a cooling line therein, and a lower mold installed on the lower plate so as to correspond to the upper mold and having a cooling line therein. In an apparatus;

The lower mold includes: a low pad having contact with the material to form a material and having a cooling line therein; a first low die on which the low pad is seated and supported; and fixedly mounted on the lower plate so as to be positioned below the first low die. And a pressurizing part installed to be positioned between the first low die and the second low die, and supporting one side of the low pad in the upper die direction. In close contact with the virtual mold and the lower mold, the cooling efficiency is increased.

According to the present invention, the pressurization part is installed at the lower part of the lower mold of the lower mold, and the material is in close contact with the upper pad by the pressing part during the molding process, and thus the heat transfer rate is improved. Cooling efficiency of the heated material is improved to ensure a molded article having high strength and uniform quality of the entire area.

Since the present invention improves the heat transfer efficiency for the material, it is possible to shorten the molding cycle time, thereby improving the overall productivity. For example, in the case of molding using an 800 ton press apparatus (approximately 750 tons of pressing force), a cycle time of about 35 to 40 seconds is conventionally formed for one molded article, whereas the present invention having a pressurizing unit is 15 to 20. Since the cycle time of about seconds is provided, the molding cycle time is reduced by almost half.

The present invention has a simple structure in which the pressing portion is installed in the lower portion of the lower pad of the lower mold, and thus can be simply applied to the hot press molding apparatus used in the prior art without changing the mold structure and the equipment structure entirely, and thereby, the overall equipment cost. And manufacturing costs can be reduced, and there is a very large ripple effect on industrial sites in the technology field.

According to an embodiment of the present invention, a pressurizing unit is divided into a first pressurizing unit having a long stroke, and a second pressurizing unit having a short stroke having a relatively short stroke compared to the first pressurizing unit, and the first pressurizing unit is disposed in the primary pressurizing section. The low center pad is supported (pressurized), and the first pressurizing part and the second pressurizing part support (pressurize) the low center pad with respect to the secondary pressure section, thereby maintaining the descending speed of the upper mold by the press to the maximum. Full contact with the upper and lower molds, the mass production rate is increased while the loss time during mass production.

The present invention is to straighten the cooling water supply line of the mold for press hardening, it is possible to simplify the cooling line located in the mold, through which uniform cooling, that is, the cooling blind spots generated in the conventional cooling line does not occur. It is possible to uniformly cool the material, thereby improving the overall cooling efficiency and improving the physical properties of the molding.

Since the present invention can straighten and simplify the cooling line, it is possible to easily meet the required molding load due to the structural problems of the mold, it is possible to facilitate the design and manufacture of the mold.

In the present invention, in the case of a two-cavity structure having two molding spaces, one of the two lower molds, the reinforcing pressure portion is installed between the lower mold and the lower plate, the thickness error of the material (the thickness of the material is not constant When one of the moldings cannot be uniformly cooled due to an error generated), the two-cavity moldings are uniformly cooled by the pressing force correction by the reinforcing pressurizing unit.

1 is an exemplary view showing a configuration according to the present invention

2 is an exemplary view showing a configuration of a molding according to the present invention

Figure 3 is an exemplary view showing the configuration of the upper mold according to the present invention

4 is an exemplary view showing a configuration of a lower mold according to the present invention

Figure 5 is another exemplary view showing the configuration of the lower mold according to the present invention

6 is an exemplary view showing a configuration of a low center pad according to the present invention;

7 is an exemplary view showing a configuration of a cooling line according to the present invention.

8 is an exemplary view showing a configuration of a conventional cooling line

9 is an exemplary view showing an assembled state of the pressing unit according to the present invention.

10 is an exemplary view showing a configuration of a pressing unit according to the present invention

11 is an exemplary view showing an operating state according to the present invention (falling section)

12 is an exemplary view showing an operating state according to the present invention (first pressure section)

13 is an exemplary view showing an operating state according to the present invention (second pressure section)

14 is an exemplary view showing a configuration in which the correction pressure unit according to the present invention is installed

15 is a graph showing the results according to the embodiment of the present invention

(Explanation of the sign)

(100): Lower die 110: First low die

111: upper surface 112: seating hole

(113): lower surface 114: first pressure hole

115: sliding block 120: the second low die

(121): upper surface 122: second pressure hole

(123): mounting hole 130: low pad

140: low steel portion (141): low body plate

(142): Low Steel (143): Lower Forming Groove

(144): low gas spring (150): low center pad

(151): Low Pad Steel (152): Low Pad Body

(153): Guidepost (154): Key

(155): Keyway (160,170): Low Cooling Line

180: pressure unit 181: first pressure unit

(182): second pressing section (183): first spring plate

(183a): Stroke hole (183b): Spring mounting hole

(183c): First through hole (183d): Upper stroke hole

(183e): Lower stroke hole (183f): Upper surface

(183g): Lower surface (184): Second spring plate

184a: fastening hole 184b: spring support hole

(184c): Second through hole (185): Second pressure spring

(186): Retainer 200: Pictograph

(210): Upper die (220): Upper gas spring

(221): gas spring stopper 230: upper pad

(240): upper steel part (241): upper steel plate

(242): Upper steel (243): Upper forming groove

(250): Upper Center Pad (260,270): Upper Cooling Line

300: Material 310: molding

311: bend portion 312: side wall portion

(313): Flange (500,500`): Hot Stamping Forming Equipment

(600): press machine (700): lower plate

(800): correction pressure part

1 is an exemplary view showing a configuration according to the present invention, FIG. 2 is an exemplary view showing a configuration of a molding according to the present invention, FIG. 3 is an exemplary view showing a configuration of an upper mold according to the present invention, FIG. Exemplary view showing the configuration of the lower mold according to the invention, Figure 5 is another exemplary view showing the configuration of the lower mold according to the invention, Figure 6 is an illustration showing the configuration of the low center pad according to the present invention, Figure 7 Is an exemplary view showing a configuration of a cooling line according to the present invention, Figure 8 is an exemplary view showing a configuration of a conventional cooling line, Figure 9 is an illustration showing an assembly state of the pressing unit according to the present invention, Figure 10 is Exemplary view showing the configuration of the pressing unit according to the invention, Figure 11 is an exemplary view showing a working state according to the present invention (falling section), Figure 12 is an exemplary view showing an operating state according to the present invention (first pressure section) 13 is an exemplary view showing an operating state according to the present invention (second pressure section) , That Fig. 14 is an exemplary view showing the pressure correcting portion installed configuration in accordance with the invention, Figure 15 shows a graph illustrating the effects of the present invention embodiment,

The present invention is driven by a press machine and provided with an upper mold 200 having a cooling line therein, and a lower mold 100 installed on the lower plate 700 so as to correspond to the upper mold 200 and having a cooling line therein. In the hot stamping forming apparatus 500 for molding the material 300 into the molding 310 by;

The lower mold 100 is formed of a low pad 130 in contact with the material 300 to form the material 300 and having cooling lines 160 and 170 therein, and the low pad 130 being seated and supported. A first low die 110, a second low die 120 fixed to the lower plate 700 to be positioned below the first low die 110, the first low die 110 and the second low It is installed to be located between the die 120 is configured to include a pressing unit 180 for pressing one side of the low pad 130 in the support and upper direction,

During the hot forming of the material, the material 300 is uniformly contacted with the upper mold 200 and the lower mold 100 by the pressing unit 180 to increase cooling efficiency.

The molding 310 refers to all moldings formed by hot pressing such as a hot stamping method, and in particular, the cross-sectional shape is a hat shape, that is, as shown in FIG. 2, the predetermined bending portion 311 and the bending portion. Means a molded article formed of a sidewall portion 312 positioned at both sides of the center portion 311 and a flange portion 313 positioned at the end of the sidewall portion 312 and having a hat shape in cross section. Such moldings are well-known molding shapes that are widely applied to automobile-related parts or ship-related parts, such as a center pillar, a front pillar, a rear pillar, a bumper, etc. of a vehicle, and thus detailed description thereof will be omitted. The molding 310 shown in the drawings of the present invention is shown by way of example a center pillar of an automobile.

As shown in FIG. 3, the upper die 200 is formed of an upper die 210 connected to the press 500 and a lower pad 130 connected to the upper die 210 to be attached to the upper die 210. An upper pad 230 for molding the material 300 into the molding 310, wherein the upper pad 230 is an upper steel part supported by the plurality of upper gas springs 220 on the upper die 210. 240 is inserted into the upper molding groove 243 fixedly installed on the upper die 210 and formed through the upper steel part 240 to form the bent portion 311 and the side wall portion 312 of the molding 310. The upper center pad 250 is included.

The upper portion 240 is an upper plate 241 supported by the upper gas spring 220 of the upper die 210 and the flange portion 321 of the molded article is fixed to the upper plate 241 It includes an upper 242 for molding.

The upper center pad 250 and the upper 242 form a material by directly contacting the material, and cooling lines 260 and 270 are installed inside the upper center pad 250 and the upper gas spring 220. The gas spring stopper 221 fixed to the plate 241 is provided. That is, the upper part 240 is supported and connected by the upper gas spring 220 by the gas spring stopper 221. Reference numeral 280 is a pictorial guide.

As shown in FIGS. 4 to 6, the low pad 130 is fixed to the first low die 110 and has a low steel portion 140 having a lower molding groove 143 and the first low. The low center pad 150 is installed to be movable in the die 110 and inserted into the lower molding groove 143 of the low steel part 140 to form the bent part 311 of the molding.

As shown in FIGS. 4 to 6, the low steel part 140 is a low body plate 141 fixed to the first low die 110 and a fixed body fixed to the low body plate 141. And a low steel 142 for molding the flange portion 313 and the side wall portion 312.

The low body plate 141 is provided with a plurality of low gas springs 144 corresponding to the upper gas springs 220. That is, the low gas spring 144 is supported by the gas spring stopper 221 of the upper gas spring 220, the upper gas spring is lowered, the low gas spring 144 is a gas spring, more preferably the pressurization time It consists of a color gas spring whose timing is adjusted.

As shown in FIGS. 4 to 7, the row center pads 150 are formed by being separated into a plurality of centers of the curved portions 314 of the molded curved portions 311. That is, when the curved portion 314 of the bent portion is one place, the low center pad 150 is formed in two, and when the curved portion 314 of the bent portion is formed in two, the low center pad 150 is separated into three. Can be formed. The low center pad 150 shown in the present invention shows a molded article having one curved portion 314 as an example, such as the automobile center pillar shown in FIG. ) Is shown in two separate configurations.

Each of the row center pads 150, which is separated into one or a plurality, is provided with a low pad steel 151 in contact with the material 300 when the upper die 200 descends due to a press force, and the low pad steel 151. It is connected to the lower portion of the) includes a low pad body 152 supporting the low pad steel 151.

In addition, as shown in FIG. 6, a key 154 protrudes from the lower pad steel 151, and a key groove 155 is formed in the low pad body 152 to insert the key 154. Thus, the low pad steel 151 and the low pad body 152 may be integrated by key / key groove coupling and bolt coupling.

In addition, a lower portion of the low pad body 152 is provided with a guide post 153 penetrating through the first and second low dies 110 and 120 and the pressing unit 180, and the guide post 153 is pressurized with an upper die. Guides the lowering of the low center pad 150 by.

In addition, cooling lines 160 and 170 are installed inside the low pad steel 151 and the low steel 142.

The upper center pads 250, the upper 242, the low pad steel 151, and the low steel 142 having the cooling lines 160, 170, 260, and 270 are respectively provided with a plurality of steel blocks. It is to be made by the assembly of (SB), the plurality of steel blocks (SB) are connected to each other by a connection bolt (CB) to form the respective cooling line (160, 170, 260, 270). At this time, the O-ring (R) is installed between the cooling line of the one steel block and the cooling line of another steel block in contact with it. That is, each of the cooling lines (160, 170, 260, 270) is connected to maintain the watertight with each other by the coupling force of the O-ring (R) and the connection bolt (CB), the cooling lines (160, 170, 260, 270) connected in this way is the upper center pad (250), Since the upper steel 242, the low pad steel 151, and the low steel 142 are linearly formed, the uncooled zone generated in the conventional cooling line is not generated, and the cooling fluid flow resistance value is minimized.

The connection relationship between the cooling lines 160, 170, 260, and 270 will be described in more detail. Since the assembly methods of the upper center pad 250, the upper steel 242, the low pad steel 151, and the low steel 142 are the same, cooling is performed. FIG. 7 simplifies the connection relationship between the lines 160, 170, 260, and 270. FIG.

FIG. 7A illustrates a simplified assembly relationship, in which the upper center pad 250, the upper 242, the low pad steel 151, and the low steel 142 are first, second, third and fourth. When the steel blocks b1, b2, b3, and b4 are formed, the first and second steel blocks b1 and b2 are bolted together, and the third steel block b3 is formed on the second steel block b2. The fourth steel block b4 is bolted to the three steel blocks b3 to integrate the first, second, third and fourth steel blocks.

At this time, an O-ring r1 is installed between the first and second cooling lines w1 and w2 of the first and second steel blocks b1 and b2, and the second and third steel blocks b2 and b3 are formed. O-ring (r2) is installed between the 2,3 cooling line (w2, w3), O-ring (r3) between the third, fourth cooling line (w3, w4) of the third, fourth steel blocks (b3, b4) The first, second, third and fourth cooling lines w1, w2, w3 and w4, that is, the cooling lines 160, 170, 260 and 270, are installed in a straight line by the O-rings r1, r2 and r3.

In addition, a key (k1) protruding from the lower portion of each of the first, second, third and fourth steel blocks, and the body (low body plate, low pad body, The upper plate, the upper die) is formed with a key groove k2, and the first, second, third and fourth steel blocks and the body are bolted.

7 (b) shows the cooling lines 160 and 170 located in the low pad steel 151 and the low steel 142, and the other end at one end of the low pad steel 151 and the low steel 142. It can be seen that the cooling lines 160 and 170 are positioned in a straight line.

That is, the cooling line 900 of the conventional die die consisting of a plurality of steel blocks, as shown in Figure 8, due to the connection between the steel blocks the cooling line is a plurality of bending from the mold steel 910 to the mold plate 920. Since the uncooled zone 930 and the cooling resistance zone 940 are generated, the present invention is connected to the cooling lines 160, 170, 260, 270 in a straight line, so that the uncooled zone and the cooling resistance zone do not occur. do.

As shown in FIGS. 4 to 6, the first low die 110 has a low steel portion 140 fixedly installed on an upper surface 111 and is inserted and seated so that the low center pad 150 is movable. The first mounting hole 112 is formed to have a predetermined depth at the upper surface 111, and one side of the pressing unit 180 is inserted into the lower surface 113 so as to communicate with the mounting hole 112. The hole 114 is formed to have a predetermined depth. In this case, the seating hole 112 and the first pressing hole 114 is formed in the first low die 110 to communicate with each other and to have a step.

In addition, a plurality of sliding blocks 115 are further provided around the seating hole 112 to guide the movement of the low center pad 150.

As shown in FIGS. 4 to 6, the second low die 120 has a second pressing hole 122 in which one side of the pressing unit 180 is inserted into and supported by the upper surface 121. In the second pressing hole 122, a second post hole 123 through which the guide post 153 connected to the row center pad 150 is inserted and formed, and an installation hole 124 on which one side of the pressing unit is installed are formed. It is. In addition, the first low die 110 and the second low die 120 are bolted to each other.

The pressing unit 180 is to improve the uniform cooling and cooling efficiency by pressing the material in the upper mold direction in close contact with the material and the upper and lower molds during the molding of the material, Figures 4 to 6 9 and 10 As shown, the pressing unit 180 supports (presses) the low pad 130 with respect to the primary pressing section P1 according to the pressing force of the upper mold 200 to press the material 300 on the upper mold 200. And the lower pad 130 by secondary supporting the first pressing part 181 closely contacting the lower mold 100 and the secondary pressing section P2 according to the upper pressing force. ) And a second pressing portion 182 in close contact with the lower mold 100,

The second pressing part 182 is installed to be located between the first low die 110 and the second low die 120, and the first pressing part 181 is the second pressing part 182 and the first row. It is installed in the second low die 120 so that the upper end is in contact with the low pad 130 through the die 110.

The first pressing unit 181 is to support the raw pad 300 to the upper mold 200 and the lower mold 100 by primarily supporting the low pad 130 with respect to the primary pressing section according to the press pressing force of the upper mold. The upper end is fixed to one side of the low pad 130, that is, the lower center pad 150, and the lower end is fixed to the mounting hole 124 formed in the second pressing hole 122 of the second low die 120. The second pressing unit 182 and the first low die 110 may be installed to pass through.

The first pressing unit 181 is a support force (pressing pressure) in consideration of the lowering speed of the upper die 200 by the press in the primary pressure section (P1), and the adhesion between the low center pad 150 and the raw material 300 increases. ) Is set. That is, the first pressing part 181 is provided to have a pressurizing load of 0.05P to 0.3P with respect to the molding load P transmitted to the upper mold by the press. Since the setting of the pressure load of the first pressing unit 181 and the operation of the first pressing unit 181 in the primary pressing section P1 directly affect the molding cycle time, the setting range of the pressing load is It is a very important factor.

That is, when the pressure load of the first pressing unit 181 is less than 0.05P, it is difficult to support the balance of the low center pads, and when the pressure load exceeds 0.3P, the descending speed of the upper die by the press device is slowed down. Or, the lowering operation is not performed properly, the loss time is increased, the mass production rate is lowered.

As described above, the first pressing unit 181 may be composed of a plurality of gas springs or hydraulic springs or disk springs to stably support (pressurize) the low center pad 150. That is, the low center pad 150 is multi-point supported by a plurality of gas springs, the low center pad 150 is preferably supported by two or three or four points by the gas spring.

The second pressing unit 182 supports (presses) the low pad 130 in the secondary pressing section P2 according to the press pressing force of the upper mold to press the material 300 to the upper mold 200 and the lower mold 100. To improve the cooling efficiency of the material.

The second pressing unit 182 may include a first spring plate 183 inserted into the first low die 110, a second spring plate 184 inserted into the second low die 120, and the first spring plate 184. And a plurality of second pressing springs 185 installed to be positioned between the two spring plates 183 and 184 to elastically support the first spring plates 183 and the second spring plates 183 through the first spring plates 183. A plurality of retainers 186 are bolted to 184 to limit the range of movement of the first spring plate 183 by the second pressing spring 185.

The second pressing unit 182 may be composed of a plurality of gas springs or hydraulic springs or disk springs, preferably a gas spring or disk springs.

As described above, the pressing unit 180 including the first pressing unit 181 and the second pressing unit 182 has a supporting force (pressing force) smaller than the molding load P of the upper mold. That is, the first and second pressing portions 181 and 181 and 182 have a pressing force (supporting force) of 0.05P to 0.3P with respect to the molding load P transmitted to the upper mold by the press. The sum of the pressing force (supporting force) is smaller than the molding load (P).

The primary pressure section (P1) and the secondary pressure section (P2) is to separate the operation section of the mold during annual molding, in order to explain the molding process according to the present invention,

As shown in FIGS. 11 to 13, the upper mold 200 is lowered in the direction of the lower mold 100 by pressing, as shown in FIGS. 11 to 13, according to the present invention. The upper and lower sections P0 in which a predetermined gap G is maintained between the upper and lower upper center pads 250 is in contact with the material, and

While maintaining a predetermined gap (G) between the upper portion of the upper steel 242 and the material 300, the upper center pad 250 of the upper shape continues to descend to press the primary pressure section (P1) and press molding ,

The upper die 200 is pushed down so that there is no gap (G) between the upper aperture 242 and the lower steel 142, and the secondary 300 is pressurized. Cooling is separated into a secondary pressing section (P2) for molding the molding (310).

The predetermined gap G is a clearance for a smooth molding process and a phenomenon that the material is pinched between the upper mold and the lower mold during molding and prevents scratches, and when the material thickness is about 1.2 to 1.5 mm, 2-10 mm, Preferably it is about 2-6 mm, More preferably, it is about 5-6 mm.

Since the gap is used for deep drawing, the detailed description thereof will be omitted. In addition, the material 300 is placed so as to be positioned on the lower pad 130 of the lower mold during molding.

The first spring plate 183 is installed to be inserted into the first pressing hole 114 of the first low die, as shown in Figures 4, 5 and 10, when pressing the upper mold 200, The lower center pad 150 is inserted into the seating hole 112 of the first low die, that is, the lower center pad 150 of the lower pad body 152 of the contact support, a plurality of retainer 186 is inserted through A stroke hole 183a and a spring installation hole 183b are formed, and a plurality of first through holes 183c through which the first pressing part 181 passes is formed.

The shape of the stroke hole 183a is not particularly limited because the retainer 186 is inserted and the first spring plate 183 does not have to be separated from the second spring plate 184.

For example, the stroke hole 183a is formed such that the upper stroke hole 183d and the lower stroke hole 183e have a step difference, and the diameter d1 of the upper stroke hole 183d is formed of the lower stroke hole 183e. It is formed to be larger than the diameter (d2), the upper stroke hole (183d) to have a predetermined depth in the direction of the lower surface (183g) from the upper surface (183f) of the first spring plate, the lower stroke hole (183e) ) Has a predetermined depth in the direction of the upper surface (183f) from the lower surface (183g) of the first spring plate, the upper stroke hole (183d) and the lower stroke hole (183e) may be formed to communicate with each other.

The spring installation hole 183b is provided with a second pressing spring 185 therein, and is formed through the first spring plate 183 or in the direction of the upper surface from the lower surface 183f of the first spring plate. It may be formed to have a predetermined depth. That is, the spring installation hole 183b may be formed by deforming to fit the second pressing spring 185 to be installed.

The second spring plate 184 is installed to be inserted into the second pressing hole 122 of the second low die 120, and supports the second pressing spring 185 to which the retainer 186 is screwed. A fastening hole 184a, a spring support hole 184b to which the second pressing spring 185 is connected, and a plurality of second through holes 184c through which the first pressing part 181 passes are formed.

The second pressing spring 185 is composed of a disk spring or a gas spring or a hydraulic spring.

Since the second pressing spring 185 made of a disk spring is shown in the drawings of the present invention, the second pressing spring made of the disk spring will be described as an example, and the second pressing spring 185 is formed of the first spring plate. A plurality of disc springs 185a installed in the spring installation hole 183b and a spring guide bar having a lower end thereof fastened to the spring support holes 184b of the second spring plate 184 through the disc springs 185a ( 185b).

The retainer 186 has a retainer bolt 186a fastened to the stroke hole 183a of the second spring plate 184 and is in contact with the first spring plate and prevents the rise of the first spring plate 186b. Is formed at the top.

That is, the retainer 186 is formed by the upper stroke hole 183d and the lower stroke hole 183e having the step, when the stroke hole 183a is formed at the elasticity (pressurization force) of the second pressing spring 185. When the first spring plate 183 is raised by the distance, the distance washer 186b is in contact with the stepped portion of the upper stroke hole 183d and the lower stroke hole 183e of the first spring plate 183, and the first spring The movement range of the plate 183 is limited.

The second pressing unit 182 configured as described above, when the upper center pad 250 is lowered by the lower pressing force of the upper die 200 in the secondary pressing section P2, the first spring plate 183 is made of the first spring plate 183. The first pressure plate 185 compresses and descends while being in contact with the first spring plate 183, so that the pressing force by the second pressure spring 185 is applied to the low center pad 150 through the first spring plate 183. It is transmitted to increase the adhesion between the material 300 and the upper center pad 250 and the low center pad 150. In other words, the heat transfer efficiency of the material is improved.

In addition, the pressing force of the pressing unit 180 may be adjusted through a separate pressure supply line, or may be variously adjusted according to the molding conditions as the replacement setting by adjusting the pressure of the first and second pressing units.

The configuration of the present invention as described above is based on the 1-cavity (cavity) structure having one molding space, as shown in Figure 11 to 13, two-cavity (cavity) structure having two molding spaces In this case, two upper molds are installed side by side in the press machine, and two lower molds with pressing parts are installed side by side on the lower plate so as to correspond to the respective upper molds.

That is, in the two-cavity hot stamping apparatus 500 'in which the first mold LH and the second mold RH are driven by one press machine,

In the hot stamping forming apparatus 500 ′, an upper mold 200 of a first mold LH and a second mold RH is installed side by side in the press machine 600, and the first mold LH and the first mold LH. The lower mold of the second mold (RH) is installed side by side on the lower plate 700 so as to correspond to the respective upper mold (200),

The lower mold 100 is

A low pad 130 in contact with the material to form the material 300 and having cooling lines 160 and 170 therein;

A first low die 110 on which the low pad 130 is seated and supported;

A second low die 120 installed on the lower plate so as to be positioned below the first low die 110;

It is installed so as to be located between the first low die 110 and the second low die 120 is configured to include a pressing unit 180 for pressing one side of the low pad 130 in the upper and vertical direction.

In addition, as shown in FIG. 14, the two-cavity hot stamping forming apparatus 500 ′ has a second low die 120 having a first mold LH or a second mold RH. ) Is further installed between the lower plate 700 and the lower plate 700 so as to eliminate the gap caused by the thickness error of the material.

That is, even with the same material, there is an error with respect to the material thickness (t) even if the material of the product produced with a thickness of about 1.5 mm has a thickness error of 1.5 mm ㅁ 5% depending on the material. Thickness error of the material when the material is hot formed by a 2-cavity hot stamping forming device 500` having a first mold LH and a second mold RH by a press device. As a result of the floating phenomenon (gap) between the material located in the first mold (LH) or the second mold (RH) and the mold, the material located in the first mold (LH) or the second mold (RH) The cooling efficiency of the different from each other will cause a difference in the physical properties for the two moldings each formed in the two-cavity (cavity).

The correction pressure unit 800 according to the present invention is to prevent the lowering and deformation of physical properties of one side molding due to the thickness error of the material, the second low die 120 of the first mold (LH) or the second mold (RH) ) Is installed between the lower plate 700 and the other side mold (second mold or first mold) based on one mold (first mold or second mold) on which the correction pressure unit 800 is not installed. The material in the first mold LH or the second mold RH is brought into contact with the mold by the same pressure so as to uniformly cool the material.

The correction pressure unit 800 may use a variety of well-known springs, such as gas spring, hydraulic spring, disk spring, like the pressure unit 180 of the present invention, preferably using a gas spring or a disk spring. That is, the correction pressing unit 800 may be configured in the same configuration as the second pressing unit.

In addition, the pressing force of the correction pressure unit 800 as described above can be adjusted through a separate pressure supply line, or can be adjusted in response to a variety of situations quickly according to the replacement setting by adjusting the pressure.

Hereinafter, the hot stamping molding method according to the present invention will be described.

11 is an exemplary view showing an operating state according to the present invention (falling section), Figure 12 is an exemplary view showing an operating state according to the present invention (first pressure section), Figure 13 is an operating state according to the present invention Illustrated diagram (second pressure section) shown,

The present invention is a material input step of inserting the material to be seated on the lower pad of the lower mold;

An upper mold lowering step in which a predetermined gap G is maintained between the upper upper stylus 242 and the raw material 300 by a press, and the upper upper mold lowers so that the upper center pad 250 of the upper mold contacts the raw material;

A first pressurizing step in which the upper center pad 250 of the upper die is lowered while the predetermined gap G is maintained between the upper aperture 242 and the raw material 300 to pressurize the raw material 200 first;

The upper die 200 is pushed down so that there is no predetermined gap (G) between the upper upper stylus 242 and the raw material 300 so that the raw material 300 is secondaryly molded and the raw material is formed by cooling lines in the upper die and the lower die. Secondary pressing step is cooled to form a molding (310);

After the secondary pressing step, the material discharge step of raising the upper mold and separating the material from the lower mold;

In the first pressing step, the first pressing part 181 of the pressing unit 180 presses and supports the low center pad 150 of the low pad so that the material comes into close contact with the upper center pad 250 of the upper type.

In the secondary pressing step, the lower center pad 150 of the low pad is pressed and supported by the pressing unit 180, the first pressing unit 181, and the second pressing unit 182. And in close contact with the low center pad 150 is to improve the cooling efficiency of the material.

At this time, the sum of the holding forces (pressing pressures) of the first pressing unit 181 and the second pressing unit 182 is to have a holding force (pressing pressure) smaller than the upper mold forming load (P). That is, the first pressing portion 181 has a pressing force (supporting force) of 0.05P to 0.3P with respect to the molding load P transmitted to the upper mold by the press, and the second pressing portion 182 has 0.95P. The pressing force of ˜0.7P is provided, and the sum of the pressing force (supporting force) of the first and second pressing parts 181 and 182 is smaller than the molding load P.

Further, the predetermined gap G has a thickness of about 1.2 to 1.5 mm, preferably about 2 to 10 mm, preferably about 2 to 6 mm, and more preferably about 5 to 6 mm.

The upper die lowering step is a step in which the upper die is lowered in the material direction by a press device, and the gas spring stopper 221 installed on the upper upper gas spring 220 of the upper die contacts the lower gas spring 144 of the upper die. The upper center pad 250 is in contact with the material positioned on the low center pad of the low pad, and the upper type upper 242 has a predetermined gap with the material 300 positioned on the low steel portion 140 of the low pad. The upper die is lowered to maintain (G).

The first pressurization step is a step in which the upper center pad 250 of the upper die is pressed down by compressing the upper gas spring 220 by the pressing force of the press, and thus the material 200 is first press-molded. The 240 is supported by the low gas spring 144 in contact with the gas spring stopper 221 of the upper gas spring, so that a predetermined gap G is maintained between the upper type upper steel 242 and the material 300. In this case, the upper center pad 250 is lowered until the low center pad 150 is in contact with the second pressing part 182 of the pressing part, and the first pressing part 181 of the pressing part moves the material 300. As the material is pressed in the upward direction, the material is brought into close contact with the upper center pad 25 of the upper mold and the lower center pad 150 of the lower mold.

The secondary pressurization step is the upper die is lowered by the pressing force of the press, press forming and cooling so that there is no predetermined gap (G) between the upper die and the material and the lower die, the upper die is lowered by the pressing force of the press lower gas spring The first pressurizing part and the second pressurizing part of the pressurizing part are compressed, and the material is pressed upwardly by the first and second pressurizing parts, so that the entire material surface is upper upper center pad 25 and lower lower center pad. In close contact with the 150, the material is cooled by the cooling lines installed in the upper and lower molds.

In addition, the present invention, if the physical properties of the two moldings formed in a two-cavity (cavity) having a first mold (LH) and a second mold (RH) after the material discharge step, the first mold (LH) And adjusting or resetting the pressing force (supporting force) of the correction pressing unit so that the physical properties of the molding formed in the second mold RH are uniform.

Example

Forming load 400 TON, 1st pressure part 80 TON, 2nd pressure part 320 TON, Total press down stroke 600mm Using a hot stamping apparatus having a 5mm), the cooling time according to the material thickness was measured, the results are shown in FIG. At this time, as the control group, the cooling time for each material thickness in the state in which the first and second pressure parts were not provided was measured.

15 shows the difference in cooling rate according to the thickness of the material, when the cooling time of the present invention having the first and second pressure parts with the same material thickness is compared with the control group without the first and second pressure parts, It can be seen that there is about 50% cooling efficiency.

In addition, in the present invention having the first and second pressing portions, the upper die has a speed of 800 mm / sec (approximately 0.63 sec) in the molding lowering section, and the material is pressed by the second pressing portion in the upper mold direction In the first pressure section, it was found to have a speed of 300 mm / sec (takes about 0.43 sec). That is, the lowering speed of the upper mold of the present invention can be seen that a large difference does not occur as compared to the case where the first pressing unit is not installed, affecting the entire cycle time.

The present invention is not limited to the above-described specific preferred embodiments, and various modifications can be made by any person having ordinary skill in the art without departing from the gist of the present invention claimed in the claims. Of course, such changes will fall within the scope of the claims.

Claims (17)

The upper mold 200 is driven by a press machine and has a cooling line therein, and the lower mold 100 is installed on the lower plate 700 so as to correspond to the upper mold 200 and has a cooling line therein. In the hot stamping apparatus 500 for molding the 300 into a molding (310); The lower mold 100 is A low pad 130 in contact with the material 300 to form the material 300 and having cooling lines 160 and 170 therein; A first low die 110 on which the low pad 130 is seated and supported; A second low die 120 fixed to the lower plate 700 so as to be positioned below the first low die 110; Is installed to be located between the first low die 110 and the second low die 120 is configured to include a pressing unit 180 for pressing one side of the low pad 130 in the support and the upper mold direction, Hot stamping molding having a pressurizing portion characterized in that the material 300 is in close contact with the upper mold 200 and the lower mold 100 by the press unit 180 during hot forming so as to increase the cooling efficiency. Device. In the two-cavity hot stamping forming apparatus 500 'in which the first mold LH and the second mold RH are driven by one press machine, In the hot forming apparatus 500 ′, an upper mold 200 of a first mold LH and a second mold RH is installed side by side in the press machine 600, respectively, and the first mold LH and the second mold 2. The lower mold of the mold (RH) is installed side by side on the lower plate 700 so as to correspond to the respective upper mold (200), The lower mold 100 is A low pad 130 in contact with the material to form the material 300 and having cooling lines 160 and 170 therein; A first low die 110 on which the low pad 130 is seated and supported; A second low die 120 installed on the lower plate so as to be positioned below the first low die 110; It is installed so as to be located between the first low die 110 and the second low die 120, characterized in that it comprises a pressing unit 180 for pressing and supporting one side of the low pad 130 in the upper mold direction Hot stamping molding apparatus having a pressing portion. The method according to claim 2; Hot stem provided with a pressurizing portion, characterized in that the correction pressing portion 800 is further provided between the second low die 120 and the lower plate 700 of the first mold (LH) or the second mold (RH). Ping molding machine. The method according to claim 1 or 2; The low pad 130 is fixed to the first low die 110 and has a low steel portion 140 having a lower molding groove 143 and is installed to be movable in the first low die 110. Hot stamping apparatus having a pressing portion, characterized in that it comprises a low center pad 150 is inserted into the lower forming groove 143 of the low steel portion 140 to form the bent portion 311 of the molding. The method according to claim 4; The low steel portion 140 is a low body plate 141 is fixed to the first low die 110, the low body plate 141 is fixed to the flange portion 313 and side wall portion 312 of the molding Low steel 142, The low center pad 150 is connected to the lower pad steel 151 and the lower pad steel 151 that are in contact with the material 300 when the upper die 200 is lowered by the press force. Hot-stamping molding apparatus having a pressing unit characterized in that it comprises a low pad body (152) for supporting the pad steel (151). The method according to claim 4; The low center pad 150 is a hot stamping molding apparatus having a pressing portion, characterized in that formed in a plurality of divided around the curved portion 314 of the molded portion (311). The method according to claim 5, Hot stamping molding apparatus having a pressing portion, characterized in that the lower portion of the low pad body 152 is further provided with a guide post 153 penetrating through the first and second low dies (110, 120) and the pressing portion (180). The method according to claim 5; Each of the low steel 142 and the low pad steel 151 has a plurality of steel blocks SB connected to each other by a connecting bolt CB, and an O-ring is installed between the steel blocks and the steel blocks, thereby providing a low steel 142. And a cooling line (170,160) located in the low pad steel (151) is a hot stamping forming apparatus having a pressurizing portion characterized in that the linear connection while maintaining the watertight. The method according to claim 1 or 2; The first low die 110 has a low steel portion 140 fixedly installed on the upper surface 111, and a seating hole 112 into which the low center pad 150 is inserted to be movable. Is formed to have a predetermined depth, and the first pressing hole 114 into which one side of the pressing unit 180 is inserted into the lower surface 113 so as to communicate with the seating hole 112 has a predetermined depth. Become The second low die 120 has a second pressing hole 122 in which one side of the pressing unit 180 is inserted into and supported by an upper surface 121, and a row is formed in the second pressing hole 122. The second post hole 123 through which the guide post 153 connected to the center pad 150 is inserted, and an installation hole 124 on which one side of the pressing part is installed is formed. Stamping forming device. The method according to claim 1 or 2; The pressing unit 180, The first pressing force of the low pad 130 is primarily supported (pressurized) with respect to the primary pressing section P1 according to the pressing force of the upper mold 200 to closely adhere the material 300 to the upper mold 200 and the lower mold 100. Second pressure for holding the raw material 300 in close contact with the upper mold 200 and the lower mold 100 by secondaryly supporting the lower pad 130 with respect to the portion 181 and the secondary pressing section P2 according to the upper mold pressing force. Hot stamping forming apparatus having a pressing portion, characterized in that it comprises a portion (182). The method of claim 10; The second pressing part 182 is installed to be located between the first low die 110 and the second low die 120, and the first pressing part 181 is the second pressing part 182 and the first row. Hot stamping forming apparatus having a pressurizing portion, characterized in that is installed in the second row die 120 so that the upper end is in contact with the low pad 130 through the die (110). The method of claim 10; The first pressing part 181 has a pressure load of 0.05 P to 0.3 P with respect to the molding load P transmitted to the upper mold by a press. The sum of the pressing force (supporting force) of the first and second pressing parts (181, 182) is installed so as to be smaller than the molding load (P) hot stamping forming apparatus having a pressing portion. The method of claim 10; The second pressing unit 182 may include a first spring plate 183 inserted into the first low die 110, a second spring plate 184 inserted into the second low die 120, and the first spring plate 184. And a plurality of second pressing springs 185 installed to be positioned between the two spring plates 183 and 184 to elastically support the first spring plates 183 and the second spring plates 183 through the first spring plates 183. Hot stamping molding having a pressing portion, characterized in that it includes a plurality of retainers 186 bolted to 184 to limit the moving range of the first spring plate 183 by the second pressure spring (185) Device. The method of claim 10; The first pressurizing part (181) is a hot stamping apparatus having a pressurizing portion, characterized in that consisting of a gas spring or a disk spring or a hydraulic spring. The method of claim 13; The second pressing spring (185) is a hot stamping molding apparatus having a pressing unit, characterized in that consisting of a gas spring or a disk spring or a hydraulic spring. The upper mold 200 is driven by a press machine and has a cooling line therein, and the lower mold 100 is installed on the lower plate 700 so as to correspond to the upper mold 200 and has a cooling line therein. In the hot-stamping molding method by the hot-stamping molding apparatus of 1-cavity or 2-cavity structure for molding the 300 into the molding (310); A material input step of inserting a material to be seated on a lower pad of a lower mold; An upper mold lowering step in which a predetermined gap G is maintained between the upper upper stylus 242 and the raw material 300 by a press, and the upper upper mold lowers so that the upper center pad 250 of the upper mold contacts the raw material; A first pressurizing step in which the upper center pad 250 of the upper die is lowered while the predetermined gap G is maintained between the upper aperture 242 and the raw material 300 to pressurize the raw material 200 first; The upper die 200 is pushed down so that there is no predetermined gap (G) between the upper upper stylus 242 and the raw material 300 so that the raw material 300 is secondaryly molded and the raw material is formed by cooling lines in the upper die and the lower die. Secondary pressing step is cooled to form a molding (310); After the secondary pressing step, the material discharge step of raising the upper mold and separating the material from the lower mold; In the first pressing step, the first pressing part 181 of the pressing unit 180 presses and supports the low center pad 150 of the low pad so that the material comes into close contact with the upper center pad 250 of the upper type. In the secondary pressing step, the lower center pad 150 of the low pad is pressed and supported by the pressing unit 180, the first pressing unit 181, and the second pressing unit 182. And a hot stamping molding apparatus having a pressurizing part, which is in close contact with the low center pad 150 to improve cooling efficiency of the material. The method of claim 16; After the material discharging step, when the properties of the two moldings formed in the 2-cavity hot forming apparatus are different from each other, by adjusting or resetting the pressing force (supporting force) of the compensating pressing part installed between one lower mold and the lower plate. And a correction step of correcting the physical properties of the two moldings formed in the 2-cavity hot forming apparatus to be uniform.

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