KR20220010905A - Method of manufacturing a torsion beam for a vehicle suspension and torsion beam for a vehicle suspension - Google Patents

Abstract

The present invention relates to a method for manufacturing a torsion beam of a suspension for a vehicle, capable of simultaneously achieving weight reduction while reinforcing the strength of a torsion beam weak region. The present invention comprises: a coil preparation step of arranging a second coil on which a second steel plate having a second thickness thicker than a first thickness is wound on both sides of a first coil on which a first steel plate having the first thickness is wound; a welding step of uncoiling the first coil and the second coil, arranging the second steel plate on both sides of the first steel plate, and welding a boundary portion between the first steel plate and the second steel plate in a longitudinal direction to form a welded steel plate; a cutting step of cutting the welded steel plate to a predetermined length; a canning step of rolling the cut welded steel plate to form a pipe having a circular closed cross-section; and a beam forming step of forming a torsion beam having a "V"-shaped closed cross-section by pressing the pipe.

Description

TECHNICAL FIELD The present invention relates to a method of manufacturing a torsion beam for a vehicle suspension and a torsion beam for a vehicle suspension.

The present invention relates to a method for manufacturing a torsion beam of a vehicle suspension and to a torsion beam for a vehicle suspension, and more particularly, to a method for manufacturing a torsion beam of a vehicle suspension capable of simultaneously achieving weight reduction while reinforcing the strength of a weak region of the torsion beam, and for vehicle It relates to the torsion beam of the suspension.

The suspension of a passenger car is an essential part of vehicle operation that connects the body, powertrain, driving parts and wheels. These suspensions are divided into front and rear wheels, and the torsion beam axle (CTBA, Coupled Torsion Beam Axle), which has fewer parts and a simpler structure than the multi-link type, is advantageous in manufacturing cost compared to the multi-link type, focusing on small and semi-medium vehicles. has been widely adopted.

In general, the configuration of the torsion beam axle is composed of a trailing arm that can be connected to a wheel and a vehicle body, and a torsion beam that crosses by connecting the center of the left/right trailing arm. Such a torsion beam is an important part that controls the attitude of the wheel through the torsion action of the movement of the wheel that occurs during vehicle driving. It can be classified into two types of beam types. While the combination of V-beam and torsion bar has excellent torsional resistance, due to the increase in weight of parts, it is recently trending to be specified for reasons such as vehicle weight reduction, and tubular beam that can maximize vehicle weight reduction. type is mainly used.

However, this conventional torsion beam of the tubular beam type is advantageous for vehicle weight reduction, but has a low torsional resistance in its structure. There was a problem that occurred easily. In addition, if the material strength and thickness of the torsion beam are reinforced in order to solve these problems and secure a durable life, there is a problem in that the weight of the vehicle cannot be reduced due to an increase in the weight of the parts.

The present invention is to solve various problems including the above problems, and to provide a method of manufacturing a torsion beam for a vehicle suspension capable of simultaneously achieving weight reduction while reinforcing the strength of a torsion beam weak region, and a torsion beam of a vehicle suspension aim to However, these problems are exemplary, and the scope of the present invention is not limited thereto.

According to one embodiment of the present invention, there is provided a method for manufacturing a torsion beam of a suspension for a vehicle. In the method for manufacturing a torsion beam of a vehicle suspension, a coil in which a second coil having a second thickness thicker than the first thickness is wound on both sides of a first coil wound around a first steel sheet having a first thickness preparatory stage; After uncoiling the first coil and the second coil so that the second steel plate is disposed on both sides of the first steel plate, the boundary portion between the first steel plate and the second steel plate is welded along the longitudinal direction. A welding step of forming a welded steel sheet; a cutting step of cutting the welded steel sheet to a predetermined length; a pipe making step of roll forming the cut welded steel sheet to form a pipe making pipe having a circular closed cross-section; and a beam forming step of forming a torsion beam having a “V”-shaped closed cross-section by press-molding the pipe making pipe.

According to an embodiment of the present invention, in the coil preparation step, the first thickness of the first steel plate and the second thickness of the second steel plate may have a difference of 0.5 mm or more.

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, the diameters of the laser beams of the first laser welding machine and the second laser welding machine may be 0.8 mm to 1.2 mm.

According to an embodiment of the present invention, a distance between the laser beam of the first laser welding machine and the laser beam of the second laser welding machine may be 0.8 mm to 1.2 mm.

According to an embodiment of the present invention, the second laser welding machine may be formed to be inclined at the predetermined angle of 35 degrees to 45 degrees 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 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 an interval of 0.8 mm to 1.2 mm.

According to an embodiment of the present invention, in the welding step, the weld bead formed at the welding portion of the first steel sheet and the second steel sheet has a width of 1.5 mm to 2.5 mm, and is based on the side of the first steel sheet. As may have a tow angle of 135 degrees to 145 degrees.

According to another embodiment of the present invention, a torsion beam of a suspension for a vehicle is provided. The torsion beam of the vehicle suspension may include: a first section having the closed cross-section having the first thickness; and a second section that is formed on both sides of the first section, has the closed cross-section of the second thickness, and is coupled to a trailing arm that can be connected to a wheel and a vehicle body of the vehicle.

According to an embodiment of the present invention made as described above, a torsion beam is manufactured by using a welded steel sheet manufactured by continuously laser welding steel sheets having different thicknesses, thereby generating a torsion moment beam to which a trailing arm is attached. It is possible to manufacture a torsion beam having a thick side part and a thin middle part having a relatively small torsional moment compared to the side part.

Accordingly, it is possible to implement a method for manufacturing a torsion beam of a vehicle suspension and a torsion beam of a vehicle suspension, which can simultaneously achieve weight reduction while improving the durability life of parts by reinforcing the thickness of the durable weak part of the torsion beam. Of course, the scope of the present invention is not limited by these effects.

1 is a process flowchart sequentially illustrating a method of manufacturing a torsion beam of a vehicle suspension according to an embodiment of the present invention.
2 to 8 are cross-sectional views schematically illustrating each manufacturing process of a torsion beam of a vehicle suspension according to the process flowchart of FIG. 1 .
9 is an image showing an actual product of a vehicle suspension manufactured by the method for manufacturing a torsion beam of a vehicle suspension according to an 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 process flowchart sequentially illustrating a method for manufacturing a torsion beam of a vehicle suspension according to an embodiment of the present invention, and FIGS. 2 to 8 are each manufacturing process of a torsion beam of a vehicle suspension according to the process flowchart of FIG. are schematic cross-sectional views. And, FIG. 9 is an image showing an actual product of a vehicle suspension manufactured by the method for manufacturing a torsion beam of a vehicle suspension according to an embodiment of the present invention.

First, as shown in FIG. 1 , the method for manufacturing a torsion beam of a vehicle suspension according to an embodiment of the present invention is largely a coil preparation step (S10), a welding step (S20), and a cutting step (S30). And, it may include a pipe forming step (S40) and a beam forming step (S50).

As shown in FIG. 2 , in the coil preparation step S10 , the first steel plate 10 having a first thickness t1 is wound on both sides of the first coil C1 having a thickness greater than the first thickness t1 . A second coil C2 on which a second steel plate 20 having a thickness t2 is wound may be disposed. For example, in the coil preparation step (S10), the first thickness t1 of the first steel plate 10 and the second steel plate ( 20), the second thickness t2 may preferably have a difference of at least 0.5 mm or more. These, the steel plates 10 and 20, an ultra-high-strength steel plate may be used, for example, may have a strength of 780Mpa.

Subsequently, as shown in FIG. 3 , in the welding step S20 , the first coil C1 and the second coil C2 are uncoiled to both sides of the first steel plate 10 to the second steel plate 20 . After this arrangement, the boundary portion between the first steel plate 10 and the second steel plate 20 may be welded along the longitudinal direction. At this time, the width W1 of the first steel plate 10 and the width W2 of the second steel plate 20 disposed on both sides of the first steel plate 10 are basically the same, but it is not necessarily limited thereto, and the torsion It can be set in various ways depending on the required strength reinforcement part of the beam or the weight reduction goal.

For example, as shown in FIGS. 4 and 5 showing partial cross-sections taken along the perforated line AA of FIG. 2 , the first steel plate 10 and the second steel plate 20 in the welding step S20 are ultra-high-strength steel plates It can be welded by a low heat input laser welding process that is advantageous for securing weldability. 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 (W1) formed perpendicular to the upper surface of 20 and a second laser welding machine (W2) 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 W is inclined at a predetermined angle a1 of 35 degrees to 45 degrees with respect to the upper surfaces of the first steel plate 10 and the second steel plate 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 W1 and the laser beam B2 of the second laser welding machine W2 do not overlap each other on the welding site of the first steel plate 10 and the second steel plate 20 . The distance between the two laser beams B1 and B2 may be equal to the diameter 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 W1 and the second laser welding machine W2 may be 0.8 mm to 1.2 mm, and the laser beam of the first laser welding machine W1 The distance d between (B1) and the laser beam B2 of the second laser welding machine W2 may be 0.8 mm to 1.2 mm. As such, as a result of repeated experiments, for effective welding of the first steel plate 10 and the second steel plate 20, the laser beams B1 and B2 of the first laser welding machine W1 and the second laser welding machine W2 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 W1 and the second laser welding machine W2 are set under the above-described conditions, and the bonding surface 11 of the first steel sheet 10 and the second steel sheet are set. When welding is performed after arranging the joint surfaces 21 of (20) at intervals of 0.8 mm to 1.2 mm, as shown in FIG. 5, the joint surfaces 11 of the first steel plate 10 and the second The joint surfaces 21 of the two steel plates 20 may be joined with a weld bead (B) interposed therebetween. At this time, when the first steel plate 10 and the second steel plate 20 are welded, the gap G between the joint surface 11 of the first steel plate 10 and the joint surface 21 of the second steel plate 20 ) Most preferably 1.0 mm, equal to the diameter D of the silver laser beams B1 and B2.

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 first steel plate 10 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 to obtain a welded steel plate 30 having a predetermined width W3. can be formed. This, the welded steel sheet 30 may be cut to a predetermined length (L) through the cutting step (S30). At this time, the predetermined length L at which the welded steel sheet 30 is cut may be determined in consideration of the circumference of the pipe making pipe 40 to be piped in a pipe making step ( S40 ) to be described later.

Then, as shown in Figure 7, the welded steel sheet 30 cut to a predetermined length (L) in the pipe making step (S40) can be formed into a pipe making pipe 40 having a circular closed cross-section by roll forming. have. For example, the welded steel sheet 40 cut to a predetermined length (L) in the pipe making step (S40) is rolled little by little through a roll forming step that goes through several stages of rollers to form a round shape, and finally the abutting surface is joined by high frequency welding By doing so, the pipe making pipe 40 can be formed.

Subsequently, as shown in FIG. 8 , a torsion beam 100 having a closed cross-section of a “V” shape may be formed by press-molding a portion of the pipe making pipe 40 with a press device P. In this case, the press device P may be a hydro-forming device to easily process a cross section of a complex shape of the torsion beam 100 .

Accordingly, according to the method for manufacturing a torsion beam of a vehicle suspension according to an embodiment of the present invention, as shown in FIGS. 8 and 9 , a first section S1 having a closed cross section of a first thickness t1 and A second section (S2) formed on both sides of the first section (S1) to have a closed cross section of a second thickness (t2), and to which a trailing arm (200) capable of being connected to the wheel and body of the vehicle is coupled ), it is possible to manufacture the torsion beam 100 of the vehicle suspension 1000 including the.

Therefore, according to the method for manufacturing a torsion beam of a vehicle suspension and the torsion beam of a vehicle suspension according to an embodiment of the present invention, a welded steel sheet manufactured by continuously laser welding steel sheets 10 and 20 having different thicknesses ( By manufacturing the torsion beam 100 using 30), the side portion (the second section, S2) of the beam to which the trailing arm 200 where the torsion moment is generated is attached has a thick thickness and relatively little torsional moment occurs. The middle part (the first section, S1) may manufacture the torsion beam 100 having a thinner thickness than the side part. Accordingly, it is possible to implement a vehicle suspension that can simultaneously achieve weight reduction while improving the durability life of parts by reinforcing the thickness of the durable weak portion of the torsion beam 100 .

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
40: pipe making
100: torsion beam
200: trailing arm
1000: vehicle suspension
C1: first coil
C2: second coil
W1: 1st laser welding machine
W2: 2nd laser welding machine

Claims (10)

a coil preparation step of arranging a second coil wound on a second steel plate having a second thickness greater than the first thickness on both sides of the first coil wound on the first steel plate having a first thickness;
After uncoiling the first coil and the second coil so that the second steel plate is disposed on both sides of the first steel plate, the boundary portion between the first steel plate and the second steel plate is welded along the longitudinal direction. A welding step of forming a welded steel sheet;
a cutting step of cutting the welded steel sheet to a predetermined length;
Roll forming the cut welded steel sheet to form a pipe making pipe having a circular closed cross-section; and
a beam forming step of forming a torsion beam having a “V”-shaped closed cross-section by press-molding the tube pipe;
A method of manufacturing a torsion beam of a vehicle suspension comprising a. The method of claim 1,
In the coil preparation step,
The first thickness of the first steel plate and the second thickness of the second steel plate have a difference of 0.5 mm or more, a method of manufacturing a torsion beam for a vehicle suspension. The method of claim 1,
In the welding step,
The method of manufacturing a torsion beam for a vehicle suspension, wherein the first steel plate and the second steel plate are welded by a low heat input laser welding process. 4. The method of claim 3,
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 inclined at a predetermined angle with respect to upper surfaces of the first and second steel plates;
A method of manufacturing a torsion beam of a vehicle suspension comprising a. 5. The method of claim 4,
The diameter of the laser beams of the first laser welding machine and the second laser welding machine is 0.8 mm to 1.2 mm, a method of manufacturing a torsion beam for a vehicle suspension. 6. The method of claim 5,
The distance between the laser beam of the first laser welding machine and the laser beam of the second laser welding machine is 0.8 mm to 1.2 mm, a method of manufacturing a torsion beam for a vehicle suspension. 5. The method of claim 4,
The second laser welding machine,
The method for manufacturing a torsion beam for a vehicle suspension, which is formed to be inclined at the predetermined angle of 35 degrees to 45 degrees with respect to the upper surfaces of the first and second steel plates. 4. The method of claim 3,
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 an interval of 0.8 mm to 1.2 mm, a method of manufacturing a torsion beam for a vehicle suspension. 9. The method of claim 8,
In the welding step,
The weld bead formed at the welding portion of the first steel plate and the second steel plate has a width of 1.5 mm to 2.5 mm, and has a toe angle of 135 degrees to 145 degrees with respect to the first steel plate side, a vehicle suspension device of torsion beam manufacturing method. The torsion beam of a vehicle suspension manufactured by the method for manufacturing a torsion beam of a vehicle suspension according to any one of claims 1 to 9,
The torsion beam is
a first section having the closed cross-section of the first thickness; and
a second section formed on both sides of the first section, the second section having the closed cross section of the second thickness, and to which a trailing arm connectable to a wheel and a vehicle body is coupled;
Including, a torsion beam of a vehicle suspension.

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