KR102346892B1 - Vehicle parts manufacturing method - Google Patents

Abstract

The present invention relates to a method of manufacturing an automobile part including parts having different levels of strength. The method can include: a coil preparation step of placing a second coil on which a second steel sheet having a second level of strength lower than the first level of strength is wound, on at least one side of a first coil on which a first steel sheet having the first level of strength is wound; a welding step of uncoiling the first and second coils such that the second steel sheet is placed on the at least one side of the first steel sheet, and then, welding a border part between the first and second steel sheets in a longitudinal direction to form a welded steel sheet; a cutting step of cutting the welded steel sheet by a predetermined length; and a roll forming step of roll-forming the cut welded steel sheet into a final product including a U-shaped cross section. Therefore, the present invention is capable of improving the impact performance and reducing the weight of a vehicle at the same time.

Description

Vehicle parts manufacturing method

The present invention relates to a method of manufacturing a component for a vehicle, and more particularly, to a method for manufacturing a component for a vehicle including parts having different strengths.

The side sill part, which is the main side member of the car body, is a panel that replaces the frame at the lower part of the side of the vehicle. In the past, cold-rolled materials of 980 MPa or 1,180 MPa were applied. It is a trend that is gradually expanding as it develops. In general, side sill parts are parts having a 'C'-shaped cross section, and while 1,470 MPa grade material is applied, parts are being manufactured using roll forming.

However, in these conventional side sill parts, there may be a problem in that the vehicle body welded portion falls off due to large deformation during a side collision of the vehicle, and thus there may be a problem of lowering collision performance. As the brittleness of the In addition, due to the brittleness of the 1,470 MPa class material, there was a problem that the impact performance could be inferior due to the material fracture during a collision.

The present invention is to solve various problems including the above problems, and the strength of the part corresponding to the welding position of the side sill part of the vehicle or the part to avoid the brittleness of the material in order to prevent the material from breaking in the event of a collision An object of the present invention is to provide a method for manufacturing a vehicle part that can be formed differently from a region requiring rigidity. However, these problems are exemplary, and the scope of the present invention is not limited thereto.

According to an embodiment of the present invention, there is provided a method for manufacturing a vehicle component. The vehicle component manufacturing method may include: a coil preparation step of disposing a second coil wound around a second steel sheet having a second strength lower than the first strength on at least one side of a first coil wound on a first steel sheet having a first strength; After the first coil and the second coil are uncoiled so that the second steel plate is disposed on at least one side of the first steel plate, a boundary portion between the first steel plate and the second steel plate is welded along the longitudinal direction. A welding step to form a welded steel sheet; a cutting step of cutting the welded steel sheet to a predetermined length; and a roll forming step of roll forming the cut welded steel sheet to form a final product including a “c”-shaped cross section.

According to an embodiment of the present invention, the final product roll-formed in the roll forming step includes a body portion formed to extend long in the longitudinal direction having a “c”-shaped cross section; and a pair of wing portions extending in the width direction from both sides of the body portion.

According to an embodiment of the present invention, in the coil preparation step, the second coil is disposed on both sides of the first coil so as to be disposed in the left and right directions based on the roll forming forming direction of the roll forming step, In the welding step, after uncoiling the first coil and the second coil, a boundary portion between the first steel plate and the second steel plate can be welded parallel to the roll forming forming direction of the roll forming step By welding the first steel plate and the second steel plate in one direction, a first portion having the first strength and a second portion having the second strength and formed on both sides of the first portion are formed in the roll forming step. The welded steel sheet disposed in the left and right directions based on the roll forming forming direction may be formed.

According to an embodiment of the present invention, in the cutting step, the welded steel sheet is cut in a direction perpendicular to the roll forming forming direction of the roll forming step, and in the roll forming step, the final product is the first part The body is roll-formed with the body part to have the first strength, and the second part is roll-formed to the pair of wing parts so that the pair of wing parts have the second strength. It may be formed to have strength.

According to an embodiment of the present invention, in the coil preparation step, the second coil is disposed on one side of the first coil so that it can be disposed in the front and rear directions based on the roll forming forming direction of the roll forming step, In the welding step, after uncoiling the first coil and the second coil, a boundary portion between the first steel sheet and the second steel sheet is welded perpendicular to the roll forming forming direction of the roll forming step By welding the first steel plate and the second steel plate in one direction, the first part having the first strength and the second part having the second strength and formed on one side of the first part are formed in the roll forming step. It is possible to form the welded steel sheet disposed in the front-rear direction based on the roll forming forming direction.

According to an embodiment of the present invention, in the cutting step, the welded steel sheet is cut in a direction parallel to the roll forming forming direction of the roll forming step, and in the roll forming step, the final product is the first part A part of the body part and a part of the pair of wing parts are roll-formed, at least a part has the first strength, and the second part is roll-formed into the other part of the body part and the other part of the pair of wing parts. The other parts may be formed to have different strengths in the longitudinal direction by having the second strength.

According to an embodiment of the present invention, in the welding step, the first steel sheet and the second steel sheet may be welded by a low heat input laser welding process.

According to an embodiment of the present invention, in the welding step, the welding device for welding the first steel sheet and the second steel sheet is a first laser welding machine formed perpendicular to upper surfaces of the first steel sheet and the second steel sheet. ; and a second laser welding machine inclined at a predetermined angle with respect to the upper surfaces of the first and second steel plates.

According to an embodiment of the present invention, in the welding step, the laser beam of the first laser welding machine and the laser beam of the second laser welding machine may be formed to be spaced apart from each other by a predetermined interval.

According to an embodiment of the present invention, in the welding step, the joint surface of the first steel plate and the joint surface of the second steel plate may be disposed to be spaced apart from each other by a predetermined interval.

According to an embodiment of the present invention made as described above, by manufacturing a side sill part of a vehicle using a welded steel sheet manufactured by continuously laser welding steel sheets having different thicknesses or different strengths, corresponding to the welding position It is possible to manufacture side sill parts whose strength is lower than that of other parts that require rigidity in the part to avoid the brittleness of the material in order to prevent the material from breaking in the event of a collision.

Accordingly, it is possible to implement a vehicle component manufacturing method capable of simultaneously reducing the weight of the vehicle and improving the crash performance by applying different thickness or strength to each part according to the requirements of the vehicle component. Of course, the scope of the present invention is not limited by these effects.

1 is a flowchart sequentially illustrating a method for manufacturing a vehicle component according to an embodiment of the present invention.
2 to 7 are process diagrams schematically illustrating each manufacturing process of a method for manufacturing a vehicle component according to an embodiment of the present invention.
8 to 11 are process diagrams schematically illustrating each manufacturing process of a method for manufacturing a vehicle component according to another embodiment of the present invention.

Hereinafter, several preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Examples of the present invention are provided to more completely explain the present invention to those of ordinary skill in the art, and the following examples may be modified in various other forms, and the scope of the present invention is as follows It is not limited to an Example. Rather, these embodiments are provided so as to more fully and complete the present disclosure, and to fully convey the spirit of the present invention to those skilled in the art. In addition, in the drawings, the thickness or size of each layer is exaggerated for convenience and clarity of description.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings schematically illustrating ideal embodiments of the present invention. In the drawings, variations of the illustrated shape can be envisaged, for example depending on manufacturing technology and/or tolerances. Accordingly, embodiments of the spirit of the present invention should not be construed as limited to the specific shape of the region shown in the present specification, but should include, for example, changes in shape caused by manufacturing.

1 is a flowchart sequentially illustrating a method for manufacturing a vehicle component according to an embodiment of the present invention, and FIGS. 2 to 7 are process diagrams schematically illustrating each manufacturing process of the method for manufacturing a vehicle component according to an exemplary embodiment of the present invention .

First, as shown in Figure 1, the vehicle component manufacturing method according to an embodiment of the present invention is largely, a coil preparation step (S10), a welding step (S20), a cutting step (S30), and a roll forming step ( S40) may be included.

As shown in Figure 2, in the coil preparation step (S10), the first steel plate 10 having a first strength having a second strength lower than the first strength on at least one side of the first coil (C1) wound A second coil C2 on which the second steel plate 20 is wound may be disposed.

More specifically, the second coil (C2) on both sides of the first coil (C1) so that it can be arranged in the left and right directions based on the roll forming forming direction of the roll forming step (S40) to be described later in the coil preparation step (S10). can be placed.

Here, the first coil C1 may be a coil wound with ultra-high strength steel of 1,470 MPa class so that the final product 40 can have high strength, and the second coil C2 is welded in the final product 40 . As a material to be a part, it may be a coil wound with high-strength steel of 780 MPa class in order to prevent the welding part from falling off due to material brittleness.

Accordingly, the first steel sheet 10 wound around the first coil C1 may have the first strength higher than the second strength of the second steel sheet 20 wound around the second coil C2 . In addition, the second steel plate 20 of the second coil C2 may have a lower strength than that of the first steel plate 10 of the first coil C1, so as to be formed to a thinner thickness than the first steel plate 10. can However, the present invention is not necessarily limited thereto, and the first steel plate 10 and the second steel plate 20 may have the same thickness and may be formed with different strengths.

In addition, in this embodiment, an example is given from the step of preparing the first coil C1 on which the first steel plate 10 is wound and the second coil C2 on which the second steel plate 20 is wound, but it is not necessarily limited thereto. , it is also possible to directly arrange the first steel plate 10 and the second steel plate 20 prepared in advance in the form of a rectangular sheet material from the coil.

Next, as shown in FIG. 3 , after the second steel plate 20 is disposed on at least one side of the first steel plate 10 , the boundary portion between the first steel plate 10 and the second steel plate 20 is lengthened The welded steel sheet 30 may be formed by welding along the direction.

For example, in the welding step (S20), after the first coil (C1) and the second coil (C2) are uncoiled, the boundary portion between the first steel plate 10 and the second steel plate 20 may be welded. Thus, the first steel plate 10 and the second steel plate 20 may be welded in a direction parallel to the roll forming forming direction of the roll forming step (S40).

At this time, the first width W1 of the first steel plate 10 and the second width W2 of the second steel plate 20 disposed on both sides of the first steel plate 10 are final in the roll forming step (S40). It may be set in various ways according to the shape and requirements of the final product 40 to be molded.

In addition, in the welding step (S20), the first steel plate 10 and the second steel plate 20, can be welded by a low heat input laser welding process that is advantageous to secure the weldability of the ultra-high strength steel plate. In this way, since the first steel plate 10 and the second steel plate 20 are joined by low heat input welding using a laser welding machine, the amount of heat input during welding can be minimized, thereby improving the low-temperature toughness of the welded portion and preventing cracking. can get

More specifically, as shown in Figure 4, in the welding step (S20), the welding apparatus for welding the first steel plate 10 and the second steel plate 20, the first steel plate 10 and the second steel plate ( A first laser welding machine (R1) formed perpendicular to the upper surface of 20 and a second laser welding machine (R2) formed to be inclined at a predetermined angle (a1) with respect to the upper surfaces of the first and second steel plates 10 and 20 ) may be a dual laser welding machine including.

At this time, it may be preferable that the second laser welding machine R2 is inclined at a predetermined angle a1 of 35 degrees to 45 degrees with respect to the upper surfaces of the first and second steel plates 10 and 20, and more Preferably, it may be most preferable to be inclined at a predetermined angle a1 of 40 degrees.

In addition, the laser beam B1 of the first laser welding machine R1 and the laser beam B2 of the second laser welding machine R2 do not overlap each other on the welding site of the first steel plate 10 and the second steel plate 20 . The distance d between the two laser beams B1 and B2 may be equal to the diameter D of the two laser beams B1 and B2.

For example, the diameter D of the laser beams B1 and B2 of the first laser welding machine R1 and the second laser welding machine R2 may be 0.8 mm to 1.2 mm, and the laser beam of the first laser welding machine R1 The distance d between (B1) and the laser beam B2 of the second laser welding machine R2 may be 0.8 mm to 1.2 mm. As such, as a result of repeated experiments, in order to effectively weld the first steel plate 10 and the second steel plate 20, the laser beams B1 and B2 of the first laser welding machine R1 and the second laser welding machine R2 are used. As for the conditions, it was shown that the range of the above conditions was preferable, and more preferably, the diameter (D) of the laser beams (B1, B2) of 1.0 mm and the spacing of the laser beams (B1, B2) of 1.0 mm were most preferable. .

Therefore, as shown in FIG. 4 , the first laser welding machine R1 and the second laser welding machine R2 are set under the above-described conditions, and the bonding surface of the first steel sheet 10 having the first thickness t1 The joint surface 21 of the second steel plate 20 having a second thickness t2 thinner than the first thickness t1 and the first thickness t1 is disposed to be spaced apart at intervals of 0.8 mm to 1.2 mm, and then welding is performed. If, as shown in FIG. 5 , the joint surface 11 of the first steel plate 10 and the joint surface 21 of the second steel plate 20 may be joined with the weld bead B interposed therebetween. At this time, when the first steel plate 10 and the second steel plate 20 are welded, the gap between the joint surface 11 of the first steel plate 10 and the joint surface 21 of the second steel plate 20 is a laser beam. A 1.0 mm equal to the diameter (D) of (B1, B2) may be most desirable.

As shown in Figure 5, in the welding step (S20), the weld bead (B) formed in the welding portion of the first steel plate 10 and the second steel plate 20, the width (W4) of 1.5mm to 2.5mm ) and may have a tow angle a2 of 135 degrees to 145 degrees with respect to the second steel plate 20 side. At this time, in order to effectively join the first steel plate 10 and the second steel plate 20, which are formed with different heights due to the thickness difference, in the welding step (S20), the weld bead (B) has a width of about 2.0 mm. It may be most desirable to be created with a toe angle of about 140 degrees.

Next, as shown in FIG. 6, the first steel plate 10 and the second steel plate 20 formed on both sides of the first steel plate 10 are joined by welding to a welded steel plate having a predetermined width W3 ( 30) can be formed. This, the welded steel sheet 30, the first portion 31 having the first strength and the second portion 32 having the second strength and formed on both sides of the first portion 31 is a roll forming step ( It may be arranged in the left and right directions based on the roll forming forming direction of S40).

Subsequently, as shown in FIG. 6 , the welded steel sheet 30 may be cut to a predetermined length L through a cutting step S30 . For example, in the cutting step (S30), the welded steel sheet 30 may be cut in a direction perpendicular to the roll forming forming direction of the roll forming step (S40). In this case, the predetermined length L at which the welded steel sheet 30 is cut may be determined in consideration of the length of the final product 40 which is a side sill component for a vehicle to be finally completed in the roll forming step ( S40 ).

Subsequently, as shown in FIG. 7 , in the roll forming step ( S40 ), the cut welded steel sheet 30 may be roll formed to form a final product 40 including a “c”-shaped cross section.

As such, the final product 40 roll-formed in the roll forming step (S40) is a welded portion with the body portion 41 and other vehicle parts formed to have a “C”-shaped cross-section and to extend long in the longitudinal direction. It may be formed in a shape including a pair of wing portions 42 that are formed to extend in the width direction from both sides of the body portion 41 .

More specifically, the final product 40 is a vehicle side sill component, wherein the first portion 31 of the welded steel sheet 30 is roll-formed into the body portion 41 so that the body portion 41 has the first strength and the second part 32 of the welded steel sheet 30 is roll-formed into a pair of wing parts 42 that are welded parts, so that the pair of wing parts 42 has the second strength, so that in the width direction They may be formed to have different strengths.

Therefore, according to the method for manufacturing a vehicle component according to an embodiment of the present invention, the welded steel sheet 30 manufactured by continuously laser welding the steel sheets 10 and 20 having different thicknesses or different strengths is used in the vehicle. By manufacturing the side seal parts, the pair of wing parts 42 corresponding to the welding position can be formed with a lower strength than the body part 41, which requires rigidity so as to prevent breakage and drop-off of the weld part due to large brittleness. Thus, the brittleness of the material can be avoided.

Therefore, in the method for manufacturing a vehicle component according to an embodiment of the present invention, the thickness or strength can be applied differently for each part according to the requirements of the vehicle component, thereby achieving the effect of simultaneously achieving the weight reduction of the vehicle and the improvement of the collision performance. can have

8 to 11 are process diagrams schematically illustrating each manufacturing process of a method for manufacturing a vehicle component according to another embodiment of the present invention.

According to the method for manufacturing a vehicle component according to another embodiment of the present invention, as shown in FIG. 8 , in the coil preparation step ( S10 ), to be arranged in the front and rear direction based on the roll forming forming direction of the roll forming step ( S40 ) Thus, the second coil C2 may be disposed on one side of the first coil C1.

Subsequently, as shown in FIG. 9 , in the welding step S20 , after uncoiling the first coil C1 and the second coil C2 , the first steel plate 10 and the second steel plate 20 . A welded steel plate 30 can be formed by welding the first steel plate 10 and the second steel plate 20 in a direction perpendicular to the roll-forming forming direction of the roll forming step (S40) so that the boundary portion of the steel plate can be welded. have.

Accordingly, as shown in FIG. 10 , the welded steel sheet 30 includes a first portion 31 having the first strength and a second formed on one side of the first portion 31 having the second strength. The portion 32 may be formed to be disposed in the front-rear direction based on the roll forming forming direction of the roll forming step (S40).

Subsequently, the welded steel sheet 30 may be cut to a predetermined length (L) through the cutting step (S30). For example, in the cutting step (S30), the welded steel sheet 30 may be cut in a direction parallel to the roll forming forming direction of the roll forming step (S40). In this case, the predetermined length L at which the welded steel sheet 30 is cut may be determined in consideration of the width of the final product 40 , which is a vehicle side sill component to be finally completed in the roll forming step S40 .

Subsequently, as shown in FIG. 11 , in the roll forming step ( S40 ), the cut welded steel sheet 30 may be roll-formed to form a final product 40 including a “c”-shaped cross section.

In this way, the final product 40 roll-formed in the roll forming step (S40) has a “C”-shaped cross section and is formed to extend long in the longitudinal direction from both sides of the body 41 and the body 41 . It may be formed in a shape including a pair of wing portions 42 formed to extend in the width direction.

More specifically, the final product 40 is a vehicle side sill component, wherein the first portion 31 of the welded steel sheet 30 is rolled into a portion of the body portion 41 and a portion of the pair of wing portions 42 . Formed by forming, at least a portion has the first strength, and the second portion 32 of the welded steel sheet 30 is roll formed into the other portion of the body portion 41 and the other portion of the pair of wing portions 42, The other parts may be formed to have different strengths in the longitudinal direction by having the second strength.

For example, the front portion 40-2 of the final product 40, which must be appropriately deformed to absorb the impact during a collision, is formed with the second strength having relatively low strength, thereby preventing fracture due to high brittleness during a vehicle collision. The rear part 40-1, which must be supported while resisting the shock generated from the front part 40-2, is formed with the first strength having relatively high strength to reinforce the overall strength of the final product 40. can

Therefore, according to the method for manufacturing parts for a vehicle according to another embodiment of the present invention, using the welded steel sheet 30 manufactured by continuously laser welding steel sheets 10 and 20 having different thicknesses or different strengths to each other, By manufacturing the side sill parts, the strength of the final product 40 can be differently formed according to the required properties for each part, thereby avoiding the brittleness of the material.

Therefore, in the method for manufacturing vehicle parts according to another embodiment of the present invention, the thickness or strength can be applied differently for each part according to the requirements of the vehicle parts, thereby achieving the effect of simultaneously achieving the weight reduction of the vehicle and the improvement of the crash performance. can have

Although the present invention has been described with reference to the embodiments shown in the drawings, which are merely exemplary, those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention should be determined by the technical spirit of the appended claims.

10: first steel plate
20: second steel plate
30: welded steel plate
31: first part
32: second part
40: final product
41: body part
42: a pair of wings
C1: first coil
C2: second coil
R1: 1st laser welding machine
R2: 2nd laser welding machine

Claims (10)

a coil preparation step of arranging a second coil wound around a second steel sheet having a second strength lower than the first strength on at least one side of the first coil wound on the first steel sheet having a first strength;
After the first coil and the second coil are uncoiled so that the second steel plate is disposed on at least one side of the first steel plate, a boundary portion between the first steel plate and the second steel plate is welded along the longitudinal direction. A welding step to form a welded steel sheet;
a cutting step of cutting the welded steel sheet to a predetermined length; and
A roll forming step of roll forming the cut welded steel sheet to form a final product including a “c”-shaped cross section;
In the coil preparation step,
disposing the second coil on both sides of the first coil so as to be arranged in the left and right directions based on the roll forming forming direction of the roll forming step;
In the welding step,
After uncoiling the first coil and the second coil, the first and second coils are uncoiled in a direction parallel to the roll forming forming direction of the roll forming step so that a boundary portion between the first and second steel sheets can be welded. By welding the first steel plate and the second steel plate, the first portion having the first strength and the second portion having the second strength and formed on both sides of the first portion determine the roll forming forming direction of the roll forming step. Forming the welded steel sheet disposed in the left and right direction as a reference,
The final product roll-formed in the roll-forming step is,
a body portion in which the first portion having the first strength of the welded steel sheet is roll-formed to extend long in the longitudinal direction having a “c”-shaped cross-section; and
A pair of wing portions formed to extend in the width direction from both sides of the body portion by roll forming the second portion having the second strength lower than the first strength of the welded steel sheet; including,
A method of manufacturing a vehicle component, wherein the pair of wing portions corresponding to the welding positions with other components are formed with lower strength than the body portion requiring rigidity. delete delete The method of claim 1,
In the cutting step,
Cutting the welded steel sheet in a direction perpendicular to the roll forming forming direction of the roll forming step,
In the roll forming step, the final product is
The first part is roll-formed into the body part so that the body part has the first strength, and the second part is roll-formed into the pair of wing parts so that the pair of wing parts has the second strength, so that the width A method of manufacturing a vehicle component, which is formed to have different strengths in the direction. delete delete The method of claim 1,
In the welding step,
The method of manufacturing a vehicle component, wherein the first steel plate and the second steel plate are welded by a low heat input laser welding process. 8. The method of claim 7,
In the welding step,
A welding device for welding the first steel plate and the second steel plate,
a first laser welding machine formed perpendicular to upper surfaces of the first and second steel plates; and
a second laser welding machine formed to be inclined at a predetermined angle with respect to the upper surfaces of the first and second steel plates;
A method of manufacturing a vehicle component comprising a. 9. The method of claim 8,
In the welding step,
The laser beam of the first laser welding machine and the laser beam of the second laser welding machine are formed to be spaced apart by a predetermined interval, the method of manufacturing a vehicle component. 8. The method of claim 7,
In the welding step,
The joint surface of the first steel plate and the joint surface of the second steel plate are disposed to be spaced apart from each other by a predetermined interval, the method of manufacturing a vehicle component.

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