KR102794116B1 - Vehicle body manufacturing method combined tailor welded blank method and patchwork method - Google Patents

Abstract

The method for manufacturing a body part by combining the TWB method and the patchwork method according to the present invention comprises: a material preparation step of preparing a first blank material, a second blank material, and a third blank material as materials for the body part; a material arrangement step of butting a first edge portion of the first blank material with a third edge portion of the third blank material and overlapping the second blank material on the first blank material to patch it; a material welding step of welding the third edge portion with the first edge portion or the first edge portion and the second edge portion of the second blank material in a TWB shape and welding the patched second blank material and the first blank material to form a TWB patchwork assembly in which the first blank material, the second blank material, and the third blank material are joined; and an assembly forming step of press-forming the TWB patchwork assembly to form the body part.

Description

{VEHICLE BODY MANUFACTURING METHOD COMBINED TAILOR WELDED BLANK METHOD AND PATCHWORK METHOD}

The present invention relates to a method for manufacturing a body part by combining the TWB method and the patchwork method, which manufactures a body part by the TWB method and the patchwork method before material forming.

As global environmental regulations and carbon emission regulations are strengthened, the automobile industry is experiencing a paradigm shift from internal combustion engine vehicles to eco-friendly electric vehicles. In response to the recent trend of increasing demand for eco-friendly parts for electric vehicles due to mass production of eco-friendly electric vehicles, policies are being implemented to impose environmental fees by strengthening environmental regulations on carbon emissions generated during the manufacturing process of automobile parts.

Among the automobile body parts, body parts used to improve side collision performance, such as the center pillar outer panel, are manufactured using hot forming hot stamping manufacturing technology. Hot stamping body parts are the body parts with the highest carbon emissions among the automobile body parts. In order to respond to the environmental contribution policy arising from the manufacturing process according to global environmental regulations, it is necessary to find a solution for body parts that can respond to collision performance while reducing carbon emissions.

Republic of Korea Patent Publication No. 10-2013-0002214

The present invention has been created to solve the above problems, and its purpose is to provide a method for manufacturing a body part by combining a TWB method and a patchwork method using a blank material made of stainless steel.

In order to achieve the above-described object, the present invention provides a method for manufacturing a body part by combining a TWB method and a patchwork method, comprising: a material preparation step of preparing a first blank material, a second blank material, and a third blank material as materials for a body part; a material arrangement step of butting a first edge portion of the first blank material with a third edge portion of the third blank material and overlapping the second blank material on the first blank material to patch it; a material welding step of welding the third edge portion with the first edge portion or the first edge portion and the second edge portion of the second blank material in a TWB shape, and welding the patched second blank material and the first blank material to form a TWB patchwork assembly in which the first blank material, the second blank material, and the third blank material are joined; And a joint forming step of forming the TWB patchwork assembly by press forming the body part; In the material preparation step, compared to each other, the first blank material and the second blank material are relatively high-strength materials and thin materials, and the third blank material is relatively low-strength materials and thick materials, and at least one of the first blank material and the second blank material is made of stainless steel, and the third blank material is made of the same material as the first blank material, and the joint forming step is performed by cold forming, and in the material arrangement step, the third blank material is arranged on both sides of the first blank material so that the third edge portion is adjacent to the first edge portion of both sides of the first blank material, and the second edge portion and the third edge portion are overlapped, and in the material welding step, the second edge portion and the third edge portion are spot-welded to form a TWB, and the patched second blank material and the first blank are The materials are spot-welded to form the above TWB patchwork assembly.

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The method for manufacturing a body part by combining the TWB method and the patchwork method according to the present invention uses the TWB method and the patchwork method in combination before material molding in manufacturing the body part, so that a first blank material, a second blank material, and a third blank material can be formed into a TWB patchwork assembly and molded simultaneously, and further, since only one mold for the TWB patchwork assembly is required due to this, the investment cost for molding can be significantly reduced compared to the prior art where multiple molds are required for manufacturing individual products for each blank material.

In addition, the present invention secures crash strength by making at least one of the first blank material and the second blank material made of stainless steel, which is a high-strength, high-elongation material, and further enables the TWB patchwork assembly to be formed by cold forming in the assembly forming step, thereby reducing carbon emissions compared to the hot stamping process in response to environmental regulations.

Specifically, the present invention performs welding in the form of a TWB by performing overlap welding using a laser in addition to butt welding using a laser in the material welding step of the first embodiment, thereby improving the bonding strength of the third blank material to the first blank material and the second blank material in the TWB patchwork assembly.

In addition, the present invention performs TWB blank welding by spot welding instead of laser welding in the material welding step of the second embodiment, thereby enabling TWB blank welding without expensive laser welding equipment, thereby reducing investment costs while ensuring welding quality.

Furthermore, in the case of welding a flange portion using a conventional high-strength material, there is concern about a deterioration in weld quality due to weld brittleness, whereas in the present invention, by applying a patch blank so that a welding flange portion is formed on a third blank material, which is a low-strength material, the concern about a deterioration in weld quality due to weld brittleness of a conventional high-strength material can be resolved, and the welding rigidity and welding performance are improved.

Figure 1 is a drawing showing a side body of a car body according to conventional technology.
Figure 2 is a cross-sectional view showing A-A' of Figure 1.
FIG. 3 is a drawing showing, as an example, the center filler inner panel and the center filler inner reinforcement panel in the side body of FIG. 2, each formed as a single piece and then joined together.
Figure 4 is a flow chart showing a method for manufacturing a body part by combining the TWB method and the patchwork method according to the present invention.
FIG. 5 is a drawing showing a part of a body part manufactured by a method for manufacturing a body part according to the first embodiment of the present invention.
Figure 6 is a cross-sectional view taken along line B-B' of Figure 5.
Figure 7 is a drawing showing a TWB patchwork assembly before press forming the body part of Figure 5.
FIG. 8 is a drawing showing a part of a body part manufactured by a method for manufacturing a body part according to a second embodiment of the present invention.
Figure 9 is a cross-sectional view taken along line B-B' of Figure 8.
Figure 10 is a drawing showing a TWB patchwork assembly before press forming the body part of Figure 8.
FIG. 11 and FIG. 12 are drawings showing a portion of a body part manufactured by a method for manufacturing a body part according to a third embodiment of the present invention.

Hereinafter, preferred embodiments will be described in detail with reference to the attached drawings so that those skilled in the art can easily practice the present invention. However, when describing preferred embodiments of the present invention in detail, if it is determined that a specific description of a related known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. In addition, the same reference numerals are used throughout the drawings for parts that have similar functions and actions. In addition, in this specification, terms such as “upper”, “upper part”, “upper surface”, “lower”, “lower part”, “lower side”, “side”, etc. are based on the drawings, and may actually vary depending on the direction in which the components are arranged.

In addition, throughout the specification, when a part is said to be 'connected' to another part, this includes not only the case where it is 'directly connected' but also the case where it is 'indirectly connected' with another component in between. Also, 'including' a component means that it can include other components rather than excluding other components unless specifically stated otherwise.

FIG. 1 is a drawing showing a side body of a car body according to the prior art, FIG. 2 is a cross-sectional view showing A-A' of FIG. 1, and FIG. 3 is a drawing showing a center pillar inner panel and a center pillar inner reinforcement panel of the side body of FIG. 2 each formed as a single product and then combined.

Referring to the drawing, the side body of the car body includes a center pillar (CP). The center pillar (CP) is a pillar located between the front door and the rear door and is also called a B pillar. This center pillar (CP) safely protects the driver from a collision accident that may occur from the side. In addition, the center pillar (CP) acts as a pillar that supports the car body and the roof, and protects the passengers from injuries when the car roof collapses or the lower part of the car sinks when the car overturns. Specifically, the center pillar (CP) includes a center pillar inner panel (1), a center pillar inner reinforcement panel (2), a center pillar outer panel (3), and a side outer panel (4), and these car body parts are arranged sequentially from the inside to the outside. For reference, FIG. 3 illustrates a portion of a center pillar inner panel (1) that is substantially formed long.

Meanwhile, the center filler inner panel (1) and the center filler inner reinforcement panel (2) are each formed as a single piece as shown in Fig. 3 and then joined by welding. That is, each mold is manufactured so that each of the center filler inner panel (1) and the center filler inner reinforcement panel (2) can be formed, and the blank materials of each part are used to form the individual pieces, and then the formed individual pieces are joined by welding, thereby assembling the center filler inner panel (1) and the center filler inner reinforcement panel (2). According to this prior art, there is a limitation in that expensive mold manufacturing investment costs are incurred for the production of each individual piece.

Figure 4 is a flow chart showing a method for manufacturing a body part by combining the TWB method and the patchwork method according to the present invention.

In addition, FIG. 5 is a drawing showing a part of a body part manufactured by a method for manufacturing a body part according to the first embodiment of the present invention, FIG. 6 is a cross-sectional view taken along line B-B' of FIG. 5, and FIG. 7 is a drawing showing a TWB patchwork assembly before press-forming the body part of FIG. 5.

And FIG. 8 is a drawing showing a part of a body part manufactured by a body part manufacturing method according to a second embodiment of the present invention, FIG. 9 is a cross-sectional view showing B-B' of FIG. 8, and FIG. 10 is a drawing showing a TWB patchwork assembly before press-forming the body part of FIG. 8. For reference, FIGS. 5 to 12 show a part of a body part (100) formed substantially long.

The present invention is a method for manufacturing a body part by combining the TWB method and the patchwork method, and as an example, a center pillar outer panel or side sill, which is a body part, can be manufactured.

At this time, the TWB (Tailor Welded Blank) method is a method of welding materials with different strengths or thicknesses to create a single part. Through this TWB method, materials with the necessary strength and thickness are placed in each part of the body parts, so that the overall weight can be reduced and the strength can be increased only in the necessary parts. In other words, since thick materials do not have to be used in parts that do not necessarily require high strength, unnecessarily thick materials are not used in those parts. Of course, there is a method of adding reinforcing material and welding it instead of this TWB method, but this method has the disadvantage of causing deformation of the welded part because it requires another welding process to add reinforcing material to an already-made part, and furthermore, it has the disadvantage of being inefficient in terms of working time and labor load.

And, the patchwork method is a manufacturing method that welds two different body parts from a blank material state and forms them simultaneously. In other words, the patchwork method is a method that partially reinforces the parent material using a reinforcing plate, and before the forming process, a patch such as a reinforcing plate is joined so that the parent material and the patch are formed simultaneously, which can reduce the investment cost of the mold.

Next, we will examine the present invention, which is characterized by the combined use of the TWB method and the patchwork method prior to material forming in manufacturing body parts.

The method for manufacturing a body part by combining the TWB method and the patchwork method according to the present invention includes a material preparation step (S100), a material arrangement step (S200), a material welding step (S300), and a joint forming step (S400), as illustrated in FIG. 4.

First, the material preparation step (S100) is a step of preparing a first blank material (110), a second blank material (120), and a third blank material (130) as materials for the body part (100).

Next, the material arrangement step (S200) is a step of placing the first edge portion (111) of the first blank material (110) and the third edge portion (131) of the third blank material (130) against each other as shown in FIG. 7 and FIG. 10, and overlapping the second blank material (120) onto the first blank material (110) to patch it.

Next, the material welding step (S300) is a step of welding the third edge portion (131) to the first edge portion (111) or the first edge portion (111) and the second edge portion (121) of the second blank material (120) in a TWB shape as illustrated in FIGS. 7 and 10, and welding the patched second blank material (120) and the first blank material (110), thereby forming a TWB patchwork assembly (190) in which the first blank material (110), the second blank material (120), and the third blank material (130) are combined.

Lastly, the assembly forming step (S400) is a step of forming a body part (100) by press forming a TWB patchwork assembly (190) as shown in FIGS. 5 and 6, 8 and 9.

For reference, in this specification, the portions formed by the first blank material (110), the second blank material (120), and the third blank material (130) in the body parts (100) of FIGS. 5 and 6, FIGS. 8 and 9 are indicated by the same drawing reference numerals as the first blank material (110), the second blank material (120), and the third blank material (130) of FIGS. 7 and 10.

Specifically, in the first and second embodiments of the present invention, the material preparation step (S100) is a step of preparing a first blank material (110) and a second blank material (120), which are relatively high-strength materials compared to each other, and a third blank material (130) which is relatively low-strength material as materials of the body part (100). In the body part (100), the first blank material (110) and the second blank material (120) positioned in the central portion in the drawing may be made of high-strength materials to secure collision rigidity, and the third blank materials (130) positioned on both sides may be made of low-strength materials to improve collision absorption. In addition, since the third blank materials (130) positioned on both sides in this way are made of low-strength materials, although not shown in the drawing, welding performance can be secured when other parts, such as side outer panels, are welded and connected. Furthermore, since the central portion made of the first blank material (110) and the second blank material (120), which are high-strength materials overlapping in two layers, secures sufficient collision rigidity, as shown in the drawing, each of the first blank material (110) and the second blank material (120) can be made of a relatively thin material, and the third blank material (130), which is a single-layer low-strength material, can be made of a relatively thick material to secure at least a certain level of collision rigidity.

In this material preparation step (S100), at least one of the first blank material (110) and the second blank material (120) may be made of stainless steel, and the third blank material (130) may be made of the same material as the first blank material (110). As an example, when the first blank material (110) is made of steel, the second blank material (120) may be made of stainless steel, and the third blank material (130) may be made of steel.

Thereafter, the assembly forming step (S400) of forming a blank assembly in which the first blank material (110), the second blank material (120), and the third blank material (130) are combined can be performed by cold forming. In other words, the assembly forming step (S400) can be formed by cold forming rather than hot forming.

In general, high-strength materials have poor elongation, that is, low ductility, or in other words, high brittleness, and thus have poor processability. In the past, body parts (100) requiring crash rigidity used high-strength materials, and since high-strength materials are difficult to form, they are formed using processes such as hot forming hot stamping. However, this hot forming hot stamping process has the problem of generating a lot of carbon emissions due to the heat source emitted from a high-temperature heating furnace.

In contrast, the present invention secures collision rigidity by making at least one of the first blank material (110) and the second blank material (120) made of stainless steel in the material preparation step (S100), and further, in the assembly forming step (S400), the TWB patchwork assembly (190) can be formed by cold forming, thereby reducing carbon emissions compared to the hot stamping process in response to environmental regulations. Furthermore, the stainless steel material has the advantage of superior corrosion resistance compared to steel.

Next, the material arrangement step (S200) is a step of arranging the third blank material (130) on both sides of the first blank material (110) so that the third edge part (131) is adjacent to the first edge part (111) on both sides of the first blank material (110), and overlapping the second edge part (121) and the third edge part (131). That is, in the material arrangement step (S200), the third blank material (130) is arranged on both sides of the first blank material (110) so that the third edge part (131) is in contact with the first edge part (111) of both sides of the first blank material (110), and at this time, the third edge part (131) is overlapped with the second edge part (121) of the second blank material (120) patched to the first blank material (110).

Next, the material welding step (S300) is a step of welding the first edge portion (111) and the third edge portion (131) by laser butt welding, welding the end of the second edge portion (121) to the third edge portion (131) in the form of a TWB, and spot welding the patched second blank material (120) and the first blank material (110) to form a TWB patchwork assembly (190).

In the case of welding in the form of TWB using a conventional laser, butt welding is performed using a laser at the part where blank materials of different thicknesses are butted together. In this case, there is concern about the deterioration of welding strength and welding quality due to the difference in thickness of the step portion.

In contrast, the present invention performs welding in the form of a TWB by performing overlap welding using a laser in addition to butt welding using a laser in the material welding step (S300), thereby improving the bonding strength of the third blank material (130) to the first blank material (110) and the second blank material (120) in the TWB patchwork assembly (190). That is, in the material welding step (S300), the first edge portion (111) of the first blank material (110) and the third edge portion (131) of the third blank material (130) are butt-welded using a laser, and the end of the second edge portion (121) of the second blank material (120) that overlaps the third edge portion (131) of the third blank material (130) is laser-welded, thereby welding the third blank material (130) to the first blank material (110) and the second blank material (120) in the form of a TWB. This means that in addition to simply butt-welding the third edge portion (131) to the first edge portion (111) using a laser, the bonding strength of the third blank material (130) in the TWB patchwork assembly (190) can be improved by overlapping-welding the second edge portion (121) using a laser.

Meanwhile, the material arrangement step (S200) according to the second embodiment of the present invention is a step of arranging the third blank material (130) on both sides of the first blank material (110) so that the third edge part (131) is adjacent to the first edge part (111) on both sides of the first blank material (110), as illustrated in FIGS. 8 to 10, and overlapping the second edge part (121) and the third edge part (131). That is, in the material arrangement step (S200), the third blank material (130) is arranged on both sides of the first blank material (110) so that the third edge part (131) is in contact with the first edge part (111) of both sides of the first blank material (110), and at this time, the third edge part (131) is overlapped with the second edge part (121) of the second blank material (120) patched to the first blank material (110).

Next, the material welding step (S300) is a step of spot welding the second edge portion (121) and the third edge portion (131) into a TWB shape, and spot welding the patched second blank material (120) and the first blank material (110) to form a TWB patchwork assembly (190).

In this way, the present invention performs TWB blank welding by spot welding instead of laser welding in the material welding step (S300), thereby enabling TWB blank welding without expensive laser welding equipment, thereby reducing investment costs while ensuring welding quality. That is, in the material welding step (S300), the second edge portion (121) of the second blank material (120) and the third edge portion (131) of the third blank material (130) are spot-welded, thereby welding the third blank material (130) to the second blank material (120) in the form of a TWB. While preventing the deterioration of welding strength and welding quality caused by butt-welding the third edge portion (131) to the first edge portion (111) using a laser in the past, the bonding strength of the third blank material (130) in the TWB patchwork assembly (190) can be improved, and since welding can be performed in the form of a TWB without using expensive laser welding equipment required for laser welding, the investment cost can be reduced while securing welding quality.

Furthermore, in the third embodiment of the present invention, unlike the first and second embodiments described above, as shown in FIGS. 11 and 12, the third blank material (130) may be placed on one end side of the first blank material (110) rather than on both sides.

For reference, in this specification, the drawing symbols of the first blank material (110), the second blank material (120), and the third blank material (130) are indicated on the portions formed by the first blank material (110), the second blank material (120), and the third blank material (130) in the body part (100) of FIGS. 11 and 12, and the following explanation will be given based on this.

In the material arrangement step (S200) according to the third embodiment of the present invention, as illustrated in FIGS. 11 to 10, the third blank material (130) is arranged on one end side of the first blank material (110) such that the third edge part (131) is adjacent to the first edge part (111) of one end side of the first blank material (110). That is, in the material arrangement step (S200), the third blank material (130) is arranged on one end side of the first blank material (110) such that the third edge part (131) is in contact with the first edge part (111) of one end side of the first blank material (110).

And in this material arrangement step (S200), as an example, as shown in FIG. 11, a second blank material (120) can be patched by overlapping the first blank material (110), and as another example, as shown in FIG. 12, a second blank material (120) can be patched by overlapping the first blank material (110) and the second blank material (120).

Next, in the material welding step (S300), the first edge portion (111) and the third edge portion (131) are butt-welded with a laser to form a TWB, and as an example, as shown in FIG. 11, the patched second blank material (120) and the first blank material (110) are spot-welded, or as another example, as shown in FIG. 12, the patched second blank material (120), the first blank material (110), and the third blank material (130) are spot-welded to form a TWB patchwork assembly (190).

As a result, the present invention can simultaneously form a first blank material (110), a second blank material (120), and a third blank material (130) into a TWB patchwork assembly (190) by using the TWB method and the patchwork method in combination before material molding in manufacturing a body part (100), and furthermore, since only one mold for the TWB patchwork assembly (190) is required due to this, the investment cost for molding can be significantly reduced compared to the prior art where multiple molds are required for manufacturing individual products for each blank material.

In addition, the present invention secures collision rigidity by making at least one of the first blank material (110) and the second blank material (120) made of stainless steel, which is a high-strength, high-elongation material, and further, by forming the TWB patchwork assembly (190) through cold forming in the assembly forming step (S400), carbon emissions can be reduced compared to the hot stamping process in response to environmental regulations.

Specifically, the present invention performs welding in the form of a TWB by performing overlap welding using a laser in addition to butt welding using a laser in the material welding step (S300) of the first embodiment, thereby improving the bonding strength of the third blank material (130) to the first blank material (110) and the second blank material (120) in the TWB patchwork assembly (190).

In addition, the present invention performs TWB blank welding by spot welding instead of laser welding in the material welding step (S300) of the second embodiment, thereby enabling TWB blank welding without expensive laser welding equipment, thereby reducing investment costs while ensuring welding quality.

Although the embodiments of the present invention have been described with reference to the attached drawings, those skilled in the art will understand that the present invention can be implemented in other specific forms without changing the technical idea or essential features thereof. Therefore, it should be understood that the embodiments described above are exemplary in all respects and are not restrictive.

100: Body parts 110: First blank material
111: First edge part 120: Second blank material
121: 2nd border 130: 3rd blank material
131: 3rd border 190: TWB patchwork combination
S100: Material preparation stage S200: Material arrangement stage
S300: Material welding stage S400: Joint forming stage

Claims (5)

A material preparation step for preparing a first blank material, a second blank material, and a third blank material as materials for body parts;
A material arrangement step of placing the first edge portion of the first blank material and the third edge portion of the third blank material against each other and overlapping the second blank material onto the first blank material to patch it;
A material welding step of welding the third edge portion with the first edge portion or the first edge portion and the second edge portion of the second blank material in a TWB shape, and welding the patched second blank material and the first blank material to form a TWB patchwork assembly in which the first blank material, the second blank material, and the third blank material are combined; and
It includes a joint forming step of forming the above TWB patchwork joint by press forming to form the above body part;
In the above material preparation stage,
In comparison with each other, the first blank material and the second blank material are relatively high-strength materials but thin materials, and the third blank material is relatively low-strength materials but thick materials.
At least one of the first blank material and the second blank material is made of stainless steel, and the third blank material is made of the same material as the first blank material.
The above-mentioned composite forming step is performed by cold forming.
In the above material arrangement step,
The third blank material is placed on each side of the first blank material so that the third edge portion is adjacent to the first edge portion on both sides of the first blank material, and the second edge portion and the third edge portion overlap each other.
In the above material welding step,
A method for manufacturing a body part by combining a TWB method and a patchwork method, wherein the second frame portion and the third frame portion are spot-welded to form a TWB shape, and the patched second blank material and the first blank material are spot-welded to form the TWB patchwork assembly.
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