CN115675345A - Profile for automobile rear bumper and manufacturing method thereof - Google Patents

Abstract

A section bar for a rear bumper of an automobile and a manufacturing method thereof are disclosed, wherein the section bar comprises a body of a rectangular pipe body structure and a reinforcing rib positioned in the middle of the body, and the section shape of the section bar is of a structure shaped like a Chinese character 'ri'; the cross section of the reinforcing rib is triangular, and the bottom edge and the top angle of the triangle are respectively connected with the inner walls of two opposite sides in the body. The invention ensures the stability of the product structure by optimally designing the reinforcing ribs and adopting the rolled section bar in combination with the online double laser welding process; the rolled section bar of the rear bumper has good quality, reasonable process and structure, and can reduce the thickness of materials under the same strength, thereby realizing the integration of light weight and functionalization.

Description

A profile for automobile rear bumper and its manufacturing method

technical field

The invention relates to the production of auto parts, in particular to a profile for the rear bumper of an automobile and a manufacturing method thereof.

Background technique

For a long time, the profile structures used in the traditional automotive rear bumper profiles are basically made by spot welding or high-frequency welding. This is mainly due to the limitation of traditional roll forming and welding process levels, and also because The profile used is a safety part, and its mechanical properties are its key factors, and it is not sensitive to operating hours and parts weight. And this kind of spot welding profile has certain benefits for cost control because of its low production technology threshold, convenient procurement and low price.

In recent years, with the continuous implementation of national energy conservation and emission reduction policies, vehicle lightweight regulations have become increasingly stringent, and traditional spot-welded steel profiles are no longer suitable for the lightweight and cost control requirements of passenger vehicles. This promotes the use of high-strength steel or even ultra-high-strength steel as raw materials for its products, and then through structural optimization design and manufacture, in order to achieve the dual effects of material lightweight and structural lightweight.

In addition, with the development of the national economy, my country's labor costs are also increasing year by year, and traditional labor-intensive industries are being replaced by advanced automated integrated production. In recent years, domestic automobiles have been competing with international counterparts at full speed. In order to achieve the purpose of reducing body weight, reducing labor costs, and improving product quality and stability, the automobile body is required to integrate structural parts with functional parts. The voice of quantifying precision profiles is getting louder and louder.

Existing automotive rear bumpers such as the "battery pack frame using rolled profiles" disclosed in Chinese patent 202021117069.X, and the "rolled profiles (Japanese font)" disclosed in Chinese patent 202030307398.X. The molding process of the above-mentioned patent profile is complicated. Compared with profiles with conventional cross-sections, the improvement in structural strength is not high, and it has no good effect on reducing body weight and labor costs.

Contents of the invention

The object of the present invention is to provide a profile for automobile rear bumper and its manufacturing method. By optimizing the design of the ribs and cooperating with the rolling profile combined with the online double laser welding process, the stability of the product structure is ensured; under the same strength, the The material is thinned to realize the integration of lightweight and functional.

For achieving the above object, technical scheme of the present invention is:

A profile for the rear bumper of an automobile, which includes a body of a rectangular tube structure and a reinforcing rib located in the middle of it, and its cross-sectional shape is a Japanese-shaped structure; wherein, the cross-section of the reinforcing rib is a triangle, and the bottom of the triangle and the top corners are respectively connected to the inner walls on both sides opposite to each other in the body.

Further, the cross-section of the reinforcing rib is triangular and extends from the apex of the triangle to form an in-line connection portion, and the connection portions of the bottom edge and apex of the triangle are respectively connected to the inner walls on opposite sides of the body.

Preferably, the profile is a triangular reinforcing rib formed by bending both ends of a steel plate in the same direction, and then bends from the apex of the triangle to both sides multiple times until the two ends of the steel plate are connected to the middle of the bottom and top surface of the triangle , forming a structural profile with a closed Japanese-shaped cross-section.

Preferably, the profile is a triangular reinforcing rib formed by bending both ends of a steel plate in the same direction, and the two sides of the steel plate at the apex of the triangle are closely attached to form a connecting part, and then bent multiple times from the lower end of the connecting part to both sides until The two ends of the steel plate are connected to the middle part of the bottom and top surface of the triangle to form a closed Japanese-shaped cross-section structural section.

The manufacture method of profile for automobile rear bumper of the present invention, it comprises the steps:

1) Select the thickness of the strip steel according to the thickness of the rear bumper profile, and select the width of the strip steel according to the expanded length of the cross section of the rear bumper profile;

2) leveling the strip;

3) Roll forming

a) The reinforcing rib is formed, and the two sides of the middle part of the cross-section of the steel strip are bent downward to form a triangle, and then the steel plate is bent outward from the corner of the triangle to form a mountain-shaped structure;

b) Bending both sides of the steel strip with a mountain-shaped cross-section inward for several times until the two ends of the steel plate are located in the middle of the top surface of the triangular bottom of the reinforcing rib, so that the cross-section of the steel strip is Japanese-shaped;

4) Welding

Through laser welding, the two ends of the steel plate located in the middle of the bottom and top surface of the triangle of the reinforcing rib are welded and connected as a whole, and welded to the bottom and top surface of the triangle of the reinforcing rib to form a closed profile section;

5) Finishing

Finish the rolled profile of the rear bumper after laser welding, and bend the profile longitudinally through roll bending equipment and molds.

Preferably, the roll forming includes: adopting deformed rolls arranged in pairs up and down, supplemented by vertical rolls and skewed insert rolls, through multi-pass roll forming, forming the cross-section of the strip into a Japanese shape; The left and right vertical rollers are used as transition rollers.

The automobile rear bumper profile of the present invention has a Japanese-shaped cross-sectional shape, including a rectangular tube structure body and middle ribs. The main body of the rectangular tube structure is mainly used as a carrier and assembly to protect passengers and connect the vehicle body; the central rib is a carrier and is mainly used to increase the rigidity and strength of the product. The main body and the middle rib of the rectangular pipe structure are integrally formed by a strip of steel.

The cross-sectional shape of the rear bumper rolling profile product described in the present invention is approximately a Japanese-shaped structure, and the reinforcing rib in the middle of the product is combined with the peripheral rectangular material through laser welding to increase the strength and rigidity of the product, thereby satisfying the requirements for ensuring the structure of the product On the premise of strength and installation function, further thinning, weight reduction, cost reduction and efficiency increase.

In the traditional manufacturing method, the two sides are flat when forming the ribs. Since the profiles used in the bumper are mostly high-strength steel, the stress cannot be released when the external shape is formed, resulting in a large rebound, resulting in an out-of-tolerance profile , resulting in defective products.

When the profile of the present invention is forming the internal reinforcing ribs, the two sides are firstly harvested into arcs, and the arcs are arched upwards. In this way, when the internal reinforcing ribs are formed and the external shape is formed, the rebound stress of the parts has been released, so that the product can be formed later. When the springback is controlled within the tolerance range of the product's profile, it lays a good foundation for the welding of the subsequent parts after closing, and improves the yield of the product.

The manufacturing method of the present invention adopts the method of firstly forming the reinforcing ribs and then forming the Japanese-shaped closed structure, and adopting a large number of shaping rollers to shape the internal structure of the parts with the raised structure. Multi-frequency shaping releases the residual stress generated during the forming process of the part, avoiding the deformation problem caused by the stress release of the part in the later stage.

Beneficial effects of the present invention:

1. Lightweight materials and structures. The cross-sectional structure of the product of the present invention is similar to a Japanese font, and the reinforcing rib in the middle adopts a triangular design. As we all know, a triangle is the strongest structural form in geometry. After CAE analysis, the present invention uses Similar to the triangular rib structure, the structural strength of the material thickness of 1.5mm is equivalent to the structural strength of the traditional structure of 3.0mm material thickness, and its lightweight effect is unmatched by existing similar patents, so that the product does not decrease in strength and stiffness To achieve thinning and weight reduction, so as to achieve the purpose of reducing energy consumption.

2. Stable quality. In order to achieve a similar Japanese-shaped structure in the traditional process, two square tubes need to be used for off-line manual welding. The production efficiency is low, the product precision is low, the quality is unstable, and the appearance quality is poor. At the same time, the bumper is a mounting part. It needs to be installed on the rear end of the body with bolts to protect the safety of the body and passengers. The mounting holes of the traditional rolling process need to be formed off-line, with low precision and efficiency. The invention adopts the optimized design of the cross-section structure of the profile, and at the same time, the product is an integrated design, which simplifies the processing procedure, can realize fully automatic online production, has high production efficiency, high installation precision, and good appearance effect.

3. Reduce cost and increase efficiency. Through the online integration process, the product of the present invention uses the rolling process as a platform to integrate leveling, pre-punching, punching, rolling, laser welding and precise sizing into one production line for automatic production, reducing Labor costs, to achieve the effect of cost reduction and efficiency increase.

Description of drawings

Fig. 1 is a perspective view of the profile embodiment 1 of the present invention.

Fig. 2 is a perspective view of the profile embodiment 1 of the present invention.

Fig. 3 is a perspective view of Embodiment 2 of the profile of the present invention.

Fig. 4 is a perspective view of Embodiment 2 of the profile of the present invention.

5 to 12 are schematic diagrams of the rolling deformation process of the profile according to the present invention.

Detailed ways

Referring to Fig. 1 and Fig. 2, the automobile rear bumper profile according to the present invention comprises a body 1 of a rectangular tubular structure and a reinforcing rib 2 located in the middle thereof, and its cross-sectional shape is a Japanese-shaped structure; wherein, the The cross-section of the reinforcing rib 2 is a triangle 21 , and the bottom and top corners of the triangle 21 are respectively connected to the inner walls of the two opposite sides of the body 1 .

Preferably, the profile is a triangular reinforcing rib formed by bending both ends of a steel plate in the same direction, and then bends from the apex of the triangle to both sides multiple times until the two ends of the steel plate are connected to the middle of the bottom and top surface of the triangle , forming a structural profile with a closed Japanese-shaped cross-section.

Referring to Fig. 3 and Fig. 4, it shows Embodiment 2 of the present invention. In Embodiment 2, the section of the reinforcing rib 2 is a triangle 21 and extends from the apex of the triangle 21 to form an in-line connecting portion 22. The triangle 21 The connecting portions 22 at the bottom and top corners of the body 1 are respectively connected to the inner walls on opposite sides of the body 1 .

Preferably, the profile is a triangular reinforcing rib formed by bending both ends of a steel plate in the same direction, and the two sides of the steel plate at the apex of the triangle are closely attached to form a connecting part, and then bent multiple times from the lower end of the connecting part to both sides until The two ends of the steel plate are connected to the middle part of the bottom and top surface of the triangle to form a closed Japanese-shaped cross-section structural section.

Referring to Fig. 3, Fig. 5～Fig. 12, the manufacturing method of profile for automobile rear bumper of the present invention, it comprises the following steps:

1) Select the thickness of the strip steel according to the thickness of the rear bumper profile, and select the width of the strip steel according to the expanded length of the cross section of the rear bumper profile;

2) leveling the strip;

3) Roll forming

a) The reinforcing rib is formed, and the two sides of the middle part of the cross-section of the steel strip are bent downward to form a triangle, and then the steel plate is bent outward from the corner of the triangle to form a mountain-shaped structure; as shown in Figures 5 to 11;

b) Bending both sides of the steel strip with a mountain-shaped cross-section inward for several times until the two ends of the steel plate are located in the middle of the top surface of the triangular bottom of the reinforcing rib, so that the cross-section of the steel strip is Japanese-shaped;

4) Welding

Through laser welding, the two ends of the steel plate located in the middle of the bottom and top surface of the triangle of the reinforcing rib are welded and connected as a whole, and welded to the bottom and top surface of the triangle of the reinforcing rib to form a closed profile section; see Figure 12 and Figure 3;

5) Finishing

Finish the rolled profile of the rear bumper after laser welding, and bend the profile longitudinally through roll bending equipment and molds.

Preferably, the roll forming includes: adopting deformed rolls arranged in pairs up and down, supplemented by vertical rolls and skewed insert rolls, through multi-pass roll forming, forming the cross-section of the strip into a Japanese shape; The left and right vertical rollers are used as transition rollers.

Example

The manufacturing process of bumper rolling profile of the present invention comprises the following steps:

1) Select the thickness of the strip steel according to the thickness of the rolled profile of the rear bumper, and select the width of the strip steel according to the unfolded length of the cross-section of the spoke profile of the rear bumper

The finished product of the rolled profile of the rear bumper in the embodiment of the present invention is: thickness=1.4mm; arc radius=6.4mm; the total width of the rolled profile of the rear bumper=120mm, the total height=68mm; the strip steel specification is: 1.4* 436.5mm; the material is HC820/1180DP ultra-high-strength steel, for slitting;

2) Leveling, through the online 21-roller precision leveler, the strip is leveled, the residual stress of the strip is eliminated, the flatness of the strip is improved, and defects such as distortion and arching after roll forming are avoided; the specific operation is: The strip steel is unrolled from the uncoiling stage and inserted into the leveler entrance, and the automatic tooling is completed, and then under the action of 21 times of vertically misaligned rollers, the strip steel is repeatedly bent up and down in waves for leveling;

3) Roll forming

Pre-sequence rough rolling of rear bumper rolling profiles: the rolling deformation process is divided into 34 passes, of which the pre-sequence rough rolling stage is from the 1st pass to the 22nd pass, and the pre-sequence rough rolling stage mainly adopts The upper and lower pairs of deformed rolls are supplemented by vertical rolls and oblique insert rolls in some passes, and 6 sets of left and right paired vertical rolls are used as transition rolls between passes to roll the strip steel It is the rough rolling stage of the front sequence section of the rolled profile of the rear bumper; as shown in Figure 3;

Through roll forming from the 1st pass to the 15th pass, the cross section of the strip steel is formed into a mountain shape;

The post-sequence rough rolling stage of the rear bumper rolling profile: the post-sequence rough rolling stage is from the 24th to the 30th pass. In the post-sequence rough rolling stage, the upper and lower paired deformed rolls are mainly used, and the Some passes are supplemented with vertical rollers and oblique insertion rollers, and 3 sets of left and right paired vertical rollers are used as transition rollers between passes, and the front section of the rear bumper rolling profile is used as a rear bumper roller The rough rolling stage of the cross-section after pressing the profile; through the 24th to 30th passes of roll forming, the cross-section of the strip is formed into a Japanese shape:

4) Welding

Through the online laser welding process, cooperate with the 3 sets of extrusion rollers in the 31st pass to weld the rectangular material around the Japanese-shaped profile to close the profile section;

5) Finishing, finishing the rolled profile of the rear bumper after rough rolling and laser welding to make it meet various precision requirements, among which, the 32nd pass and the 33rd pass adopt four-roller separation straightening head to ensure the flatness and straightness of the straight edge to meet the product requirements; the 34th pass uses a Turkish head straightening machine to adjust the twist of the bumper rolled profile to meet the product requirements;

6) In the longitudinal rolling and bending stage of the rear bumper rolling profile, the rear bumper rolling profile is longitudinally bent and formed through CNC three-roll bending equipment and molds.

Traditional automotive rear bumper profiles are rolled, using DP780 or DP980 grade steel raw materials. After roll forming, they are formed by spot welding or high frequency welding. The original specification is 120*68*2.0*1169mm tailor welding square tube.

The product of the present invention uses DP1180 grade material to achieve the effect of reducing the thickness of the product from 2.0mm to 1.4mm. At the same time, it applies rolling + online double laser welding process to realize the continuous production of closed profile products of DP1180 grade material.

Claims (6)

1. a profile for automobile rear bumper, it is characterized in that, comprise the body of rectangular pipe structure and the stiffener that is positioned at its interior middle part, its cross-sectional shape is a Japanese-shaped structure; Wherein, described stiffener section is triangle, The base and vertex of the triangle are respectively connected to two opposite inner walls of the body. 2. The section bar for automobile rear bumper as claimed in claim 1, wherein the cross section of the reinforcing rib is triangular and extends from the triangular vertex to form an in-line connecting portion, and the connection between the bottom edge and the vertex of the triangle is The parts are respectively connected to the inner walls on both sides opposite to each other in the body. 3. The section bar for automobile rear bumper as claimed in claim 1, wherein the section bar is a reinforcing rib formed by bending the two ends of a steel plate in the same direction to form a triangular rib, and then passes through multiple times from the apex of the triangle to both sides. After being bent, the two ends of the steel plate are connected to the middle of the top surface of the triangular bottom to form a closed Japanese-shaped structural profile. 4. The section bar for the rear bumper of an automobile as claimed in claim 2, wherein the section bar is formed by bending a steel plate two ends in the same direction to form a triangular reinforcing rib, and the two sides of the steel plate at the apex of the triangle are closely attached to form The connection part is bent multiple times from the lower end of the connection part to both sides until the two ends of the steel plate are connected to the middle part of the bottom edge top surface of the triangle to form a closed Japanese-shaped structural section. 5. the manufacture method of profile for automobile rear bumper as claimed in claim 1 or 2 or 3 or 4 is characterized in that, comprises the steps: 1) Select the thickness of the strip steel according to the thickness of the rear bumper profile, and select the width of the strip steel according to the expanded length of the cross section of the rear bumper profile; 2) leveling the strip; 3) Roll forming a) The reinforcing rib is formed, and the two sides of the middle part of the cross-section of the steel strip are bent downward to form a triangle, and then the steel plate is bent outward from the corner of the triangle to form a mountain-shaped structure; b) Bending both sides of the steel strip with a mountain-shaped cross-section inward for several times until the two ends of the steel plate are located in the middle of the top surface of the triangular bottom of the reinforcing rib, so that the cross-section of the steel strip is Japanese-shaped; 4) Welding Through laser welding, the two ends of the steel plate located in the middle of the bottom and top surface of the triangle of the reinforcing rib are welded and connected as a whole, and welded to the bottom and top surface of the triangle of the reinforcing rib to form a closed profile section; 5) Finishing Finish the rolled profile of the rear bumper after laser welding, and bend the profile longitudinally through roll bending equipment and molds. 6. The manufacturing method of profile for automobile rear bumper as claimed in claim 5, characterized in that, said roll forming comprises: adopting deformed rolls arranged in pairs up and down, supplemented by vertical rolls and skewed insert rolls, through multiple Pass roll forming, the cross-section of the strip steel is formed into a Japanese shape; the left and right pairs of vertical rolls are used as transition rolls between the passes.

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