CN117260184A - Manufacturing method of lightweight bumper and bumper - Google Patents

Abstract

The application provides a light bumper manufacturing method and a bumper, and belongs to the technical field of bumpers. The method comprises a rectangular straight pipe manufacturing step of processing a first positioning hole on the rectangular straight pipe, a supporting box manufacturing step of welding corrugated plates at two ends of a cylindrical supporting piece to manufacture a supporting box, and processing a second positioning hole on the supporting box, a main beam blank manufacturing step of connecting the rectangular straight pipe and the supporting box, a bending forming step of bending the main beam blank into an arched beam, and a hot gas expansion forming step of processing the arched beam into a required bumper through a hot gas expansion forming process. The method increases the supporting strength by the way of connecting the supporting boxes through spot welding, has relatively low precision requirement, simpler process and low manufacturing cost. The bumper of its preparation is for increasing the strengthening rib structure that runs through whole bumper, only increases this department intensity and improves bulk strength at the mode of surface increase indent muscle through increasing the support box structure in the place that intensity requirement is high, can further realize the lightweight.

Description

Manufacturing method of lightweight bumper and bumper

Technical Field

The application belongs to the technical field of bumpers, and particularly relates to a manufacturing method of a lightweight bumper and the bumper.

Background

The automobile bumper can absorb and slow down external impact force, protect the automobile body and improve the aerodynamic characteristics of the automobile, and belongs to a safety piece. When the bumper is impacted, the energy of the impact is absorbed, and plastic deformation is generated at the same time, so that the energy transmission is reduced.

Metallic materials, such as steel, are materials commonly used for automotive bumpers. The load capacity is strong, and the collision resistance is good. However, the steel has a high density, which is disadvantageous for weight reduction. The Chinese patent publication No. CN110576292B (publication No. 2022.05.06) discloses a manufacturing method of an automobile bumper, which is characterized in that a rectangular straight pipe and a C-shaped material are welded to obtain a Chinese character 'ri' shaped material, and the short side of the rectangular straight pipe and the C-shaped material, which are connected, is a middle reinforcing rib of the Chinese character 'ri' shaped material, so that the manufacturing process is simplified while the weight is reduced. However, the bumper obtained by the method is formed by welding two main bodies of a rectangular straight pipe and a C-shaped material, the welding distance is long, the requirement on connection precision is high, and the simplification of the process is affected.

Disclosure of Invention

In one aspect, the present invention provides a method for manufacturing a lightweight bumper, which can be manufactured into a bumper having a lightweight structure and can ensure the strength of the bumper.

In order to achieve the above purpose, the technical scheme adopted in the application is as follows: provided is a method for manufacturing a lightweight bumper, which comprises:

the rectangular straight pipe manufacturing step comprises the following steps: manufacturing a rectangular straight pipe, and penetrating two groups of first positioning holes in the side wall of the rectangular straight pipe, wherein the two groups of first positioning holes are symmetrically arranged along the extending direction of the rectangular straight pipe;

and a support box manufacturing step: welding corrugated plates at two ends of a cylindrical supporting piece to manufacture a supporting box, and forming second positioning holes penetrating the corrugated plates at two ends on the supporting box;

and (3) manufacturing a main beam blank: placing the two groups of support boxes into the rectangular straight pipe, wherein the second positioning holes on the two groups of support boxes are aligned with the two groups of first positioning holes on the rectangular straight pipe respectively, and the corrugated plates at the two ends of the support boxes are supported and abutted on the inner side wall of the rectangular straight pipe; spot welding and fixing the support box and the rectangular straight pipe at the first positioning hole and the second positioning hole, so that the rectangular straight pipe and the support box are combined to form a locally reinforced main beam blank at the support box;

bending and forming: bending the positions, close to the two ends, of the main girder blank to form an arched beam, wherein the arched beam is respectively provided with a middle preformed section, a bending preformed section and an end preformed section from the middle to the two ends, and the supporting box is positioned in the middle preformed section;

and (3) a hot air expansion forming step: adopting a hot gas expansion forming process to process the arched beam into a beam main body, correspondingly forming a middle section by a middle preformed section, correspondingly forming a bending section by a bending preformed section, correspondingly forming an end section by an end preformed section, and forming concave ribs in the middle section by distributing towards and away from the outer side wall of the bending direction of the bending section; after the beam body is cooled, the desired bumper is obtained.

Optionally, in the rectangular straight tube manufacturing step, the round tube is manufactured into a rectangular straight tube through a continuous rolling mode or the steel coil is manufactured into the rectangular straight tube through a cutting and continuous rolling combined welding mode.

Optionally, for the hot gas bulge forming process in the hot gas bulge forming step, the heated forming portion of the arched beam is realized by a hot gas bulge forming die;

the hot air expansion forming die comprises a hot air expansion upper die, a hot air expansion lower die, a high-pressure air source, an air pipe, two groups of sealing push heads and two groups of oil cylinders; the thermal expansion lower film is provided with a lower groove matched with the arched beam, the thermal expansion upper film is provided with a lower convex groove matched with the arched beam, and the lower groove is arranged opposite to the lower convex groove; the two groups of sealing push heads are respectively communicated with a high-pressure air source through air pipes, and the two groups of oil cylinders are respectively communicated with the two groups of sealing push heads; the lower groove and the lower convex groove respectively comprise a middle forming section, a bending forming section and an end forming section which are respectively arranged from the middle to two ends so as to respectively correspond to the middle section, the bending section and the end section on the beam main body; the bottom wall of the lower groove positioned in the middle forming section and the top arm of the lower convex groove positioned in the middle forming section are both provided with convex ribs;

in the hot air inflation forming step, two groups of sealing push heads are respectively in butt joint with the end parts of the two end part pre-forming sections; the side wall of the arched beam is attached to the inner side wall of the lower groove and the lower convex groove after being pressed and expanded, and the part of the arched beam, which is contacted with the convex rib, forms an inner concave rib.

Optionally, the side wall of the middle forming section is provided with a sealing bump inserted into the first positioning hole.

Optionally, a pressing step is further arranged between the bending forming step and the hot air expansion forming step;

and (3) laminating: pressing and forming the two ends of the arched beam, so that the cross section shape of one end of the end preformed section far away from the bending preformed section is gradually changed from rectangular to circular;

in the hot air inflation forming step, the end part with a circular section in the end part preformed section is in butt joint communication with the sealing push head; after the beam body is cooled, the portion of the end section, which gradually transitions from rectangular to circular in cross-sectional shape, is cut off to obtain the desired bumper.

Optionally, in the pressing step, pressing and forming the two ends of the arched beam are realized through a pressing die;

the pressing die comprises an upper pressing die, a lower pressing die and a cylindrical mandrel, wherein the upper pressing die and the lower pressing die are respectively provided with a pressing half groove corresponding to each other, and the pressing half grooves on the upper pressing die and the pressing half grooves on the lower pressing die are combined into pressing grooves which are rectangular at one end and are transited into round at the other end;

in the pressing step, a mandrel is inserted into the end part of the end part preformed section far away from the end part of the bending preformed section, then the end part of the end part preformed section far away from the bending preformed section is placed into a pressing half groove of a pressing lower die, and the pressing upper die and the pressing lower die are clamped to press and form the end part of the arched beam.

Optionally, in the rectangular straight tube manufacturing step, the rectangular straight tube is made of BR1500HS, and the wall thickness range of the rectangular straight tube is 1.8-2.5mm;

in the step of thermal expansion forming, the heating temperature of the arched beam ranges from 900 ℃ to 1000 ℃, and the pressure of the thermal expansion gas ranges from 28MPa to 32MPa.

In another aspect, the present invention provides a bumper that achieves weight reduction while ensuring strength.

In order to achieve the above purpose, the technical scheme adopted in the application is as follows: provided is a bumper including an arch body and two support boxes; the cross section of the arch main body is in a hollow rectangular shape, the arch main body comprises a middle section, a bending section and an end section which are sequentially arranged from the middle to the two ends, and each supporting box comprises a cylindrical supporting piece and corrugated plates welded at the two ends of the supporting piece;

two support boxes are symmetrically arranged in the middle section, the inner side wall of the middle section is supported on the corrugated plate, and the outer side walls of the middle section, which face and deviate from the bending direction of the bending section, are all provided with concave ribs.

Optionally, two groups of first positioning holes are formed in the side wall of the middle section in a penetrating manner, and second positioning holes formed in the supporting box in a penetrating manner are formed in the supporting box, wherein the two groups of first positioning holes are aligned with the second positioning holes in the two supporting boxes respectively; the concave ribs aligned with the corrugated plate are arranged in the concave parts on the surface of the corrugated plate.

Optionally, lightening holes are distributed on the side wall of the arched body.

The beneficial effect of the technical scheme for prior art of this application lies in:

according to the manufacturing method of the light bumper, the supporting strength is increased through the mode of connecting the supporting box through spot welding, and the two main bodies are aligned and welded relative to a continuous long distance, so that the precision requirement is lower, the process is simpler, and the manufacturing cost is low. Meanwhile, compared with the reinforcing rib structure penetrating through the whole bumper, the strength of the part, which is higher in strength requirement and is close to the bending part, is increased only by increasing the supporting box structure, the overall strength can be further reduced by increasing the inner concave ribs on the surface, and the weight is further reduced. The first positioning hole and the second positioning hole are convenient for positioning the position between the rectangular straight pipe and the support box and for spot welding connection.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are required for the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic view of a rectangular straight tube structure;

FIG. 2 is a schematic view of a support box structure;

FIG. 3 is a cross-sectional view of the main beam blank at the support box;

FIG. 4 is a schematic view of the arched beam structure prior to the lamination step;

FIG. 5 is a schematic view of the arched beam structure after the lamination step;

FIG. 6 is a schematic view of a press mold;

FIG. 7 is an enlarged view of a portion of FIG. 6 at A;

FIG. 8 is a schematic view of a beam body structure;

FIG. 9 is a schematic view of a bumper structure;

FIG. 10 is a schematic view of a hot gas expansion die;

FIG. 11 is a schematic view of a thermal expansion upper die structure;

FIG. 12 is an enlarged view of a portion of FIG. 11 at B;

FIG. 13 is an enlarged view of a portion of FIG. 8 at C;

fig. 14 is a structural cross-sectional view of the bumper at the support case.

Icon: 10. a rectangular straight tube; 11. a first positioning hole; 20. a support box; 21. a support; 22. corrugated plates; 23. a second positioning hole; 30. a main beam blank; 40. arched beams; 41. a middle preform section; 42. bending the preformed section; 43. an end pre-forming section; 50. a beam body; 51. a middle section; 52. a bending section; 53. an end section; 54. concave ribs; 55. a lightening hole;

100. a hot air expansion forming die; 101. hot air inflation upper die; 102. a lower thermal expansion die; 103. a high pressure air source; 104. an air pipe; 105. sealing the push head; 106. an oil cylinder; 107. a lower groove; 108. a lower convex groove; 109. a middle forming section; 110. bending the forming section; 111. an end forming section; 112. convex ribs; 113. a sealing bump;

200. pressing a die; 201. pressing the upper die; 202. pressing the lower die; 203. a mandrel; 204. pressing the half groove; 205. a pressing groove; 206. and positioning the boss.

Detailed Description

In order to make the technical problems, technical schemes and beneficial effects to be solved by the present application more clear, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the present application.

It will be understood that when an element is referred to as being "fixed" or "disposed" with respect to another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or be indirectly connected to the other element.

It is to be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate or are based on the orientation or positional relationship shown in the drawings, merely to facilitate description of the present application and simplify description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be configured and operated in a particular orientation, and therefore should not be construed as limiting the present application.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature.

Example 1:

the present embodiment provides a lightweight bumper manufacturing method including:

s1, manufacturing a rectangular straight pipe: based on the illustration in fig. 1, a rectangular straight pipe 10 is manufactured, two groups of first positioning holes 11 are formed in the side wall of the rectangular straight pipe 10 in a penetrating manner, and the two groups of first positioning holes 11 are symmetrically arranged along the extending direction of the rectangular straight pipe 10.

In the rectangular straight tube manufacturing step, the round tube can be manufactured into the rectangular straight tube 10 by a continuous rolling method, or the steel coil can be manufactured into the rectangular straight tube 10 by a combination of cutting and continuous rolling and welding. The continuous rolling operation is achieved by a roll former.

In this embodiment, the rectangular straight tube 10 is made of BR1500HS, belongs to high strength steel, and can be used for various automotive applications requiring high strength and good formability. The rectangular straight pipe 10 has a wall thickness of 2mm, and is reduced in weight by a thin wall thickness while ensuring strength. Of course, in other embodiments, the rectangular straight tube 10 may have a wall thickness of 1.8mm, 2.5mm, or other dimensions between 1.8mm and 2.5mm, depending on the vehicle being used.

S2, manufacturing a support box: based on the illustration of fig. 2, corrugated plates 22 are welded at both ends of a support 21 having a cylindrical shape to make a support box 20, and second positioning holes 23 penetrating the corrugated plates 22 at both ends are formed in the support box 20. The height dimension of the support box 20 is the same as the height dimension of the inside of the rectangular straight pipe 10, and the width dimension of the support box 20 is the same as the width dimension of the inside of the rectangular straight pipe 10, so that the support box 20 can be just placed inside the rectangular straight pipe 10.

S3, manufacturing a main beam blank: based on the illustration in fig. 3, two sets of support boxes 20 are placed into the rectangular straight pipe 10 from the end, the second positioning holes 23 on the two sets of support boxes 20 are aligned with the two sets of first positioning holes 11 on the rectangular straight pipe 10 respectively, and the corrugated plates 22 on the two ends of the support boxes 20 are supported and abutted on the inner side walls of the rectangular straight pipe 10. The support box 20 and the rectangular straight tube 10 are fixed by spot welding at the first positioning hole 11 and the second positioning hole 23, so that the rectangular straight tube 10 and the support box 20 are combined to form a main beam blank 30 which is locally reinforced at the support box 20.

In the final finished bumper, the strength required for the position of the support box 20 is high, and the strength required for the rest of the positions is low, so the support box 20 is provided at the corresponding position for support. Based on the illustration in fig. 3, the edges of the left and right sides of the corrugated plate 22 may be bent to fit the corners of the inner side of the rectangular straight pipe 10, so as to ensure the supporting strength.

S4, bending and forming: based on the illustration of fig. 4, the girder blank 30 is bent near both ends to form an arched beam 40. The bending operation can be realized by a pipe bender or by bending by a bending press. After the bending step is completed, the arched beam 40 forms a middle preform segment 41, a bending preform segment 42, and an end preform segment 43 from the middle to the ends, respectively, and the support box 20 is positioned within the middle preform segment 41.

S5, laminating: based on the illustration of fig. 5, the two ends of the arched beam 40 are press-formed, so that the cross-sectional shape of the end pre-forming section 43 at the end far from the bending pre-forming section 42 gradually changes from rectangular to circular.

The lamination step is provided as a transition step between the bending forming step and the hot gas expansion forming step for rounding the ends of the arched beam 40. The ends of the arched beam 40 are rounded because the arched beam 40 needs to interface with the sealing push head 105 during the subsequent hot gas expansion step, while the rounded cross-section effectively seals when in contact with the sealing push head 105.

In the press-fit step, press-fit forming of both ends of the arched beam 40 is performed by the press-fit mold 200. In detail, based on fig. 6 and 7, the press mold 200 includes a press upper mold 201, a press lower mold 202, and a mandrel 203 having a cylindrical shape. The upper pressing mold 201 and the lower pressing mold 202 are provided with pressing half grooves 204 corresponding to each other, and the pressing half grooves 204 on the upper pressing mold 201 and the pressing half grooves 204 on the lower pressing mold 202 are combined into pressing grooves 205 which are in rectangular transition from one end to the other end. In the press-fit step, the mandrel 203 is inserted into the end of the end pre-forming section 43 far from the bending pre-forming section 42 to form a support for the end pre-forming section 43 and control the wall thickness of the section at the port, and then the end of the end pre-forming section 43 far from the bending pre-forming section 42 is placed into the press-fit half groove 204 of the press-fit lower die 202, and the press-fit upper die 201 and the press-fit lower die 202 are clamped to press-fit the end of the arched beam 40. The end of the end preform section 43 remote from the bending preform section 42 is shaped by the pressing action of the two pressing half-grooves 204 to gradually transition from rectangular to circular. Meanwhile, in order to achieve axial limiting, a positioning boss 206 is disposed on the inner side wall of the pressing half groove 204, and the positioning boss 206 abuts against the end of the end pre-forming section 43.

S6, hot air expansion forming: based on the description of fig. 5, 8 and 9, the arched beam 40 is processed into the beam body 50 by adopting a hot air expansion forming process, the middle preformed section 41 corresponds to form a middle section 51, the bending preformed section 42 corresponds to form a bending section 52, the end preformed section 43 corresponds to form an end section 53, and the inner concave ribs 54 are distributed in the middle section 51 towards and away from the outer side wall of the bending direction of the bending section 52. After the beam body 50 is cooled, the portion of the end section 53 having a cross-sectional shape gradually transitioning from rectangular to circular is cut off to obtain the desired bumper.

In this embodiment, for BR1500HS material and 2mm wall thickness, the arched beam 40 is heated to 950℃and the hot gas expansion pressure is preferably 20MPa. Of course, a temperature in a certain range, such as 900 ℃, 1000 ℃ or a temperature between 900 and 1000 ℃, and a pressure in a certain range, such as 28MPa, 32MPa or a pressure between 28 and 32MPa, may satisfy the hot gas expansion forming conditions.

In the hot gas expansion forming step, for the hot gas expansion forming process in the hot gas expansion forming step, the heated formed portion of the arched beam 40 (including the formation of the concave ribs 54) is achieved by the hot gas expansion forming die 100. In detail, based on fig. 10 to 12, the hot air inflation forming die 100 includes a hot air inflation upper die 101, a hot air inflation lower die 102, a high pressure air supply 103, an air pipe 104, two sets of sealing plugs 105, and two sets of cylinders 106. Wherein the lower hot gas film has a lower groove 107 matching the arched beam 40, the upper hot gas film has a lower groove 108 matching the arched beam 40, and the lower groove 107 is disposed opposite the lower groove 108. The lower groove 107 and the lower tongue 108 each include a middle forming section 109, a bending forming section 110 and an end forming section 111 provided from the middle to both ends, respectively, to correspond to the middle section 51, the bending section 52 and the end section 53 on the beam body 50, respectively. The two groups of sealing push heads 105 are respectively communicated with the high-pressure air source 103 through air pipes 104, and the two groups of oil cylinders 106 are respectively communicated with the two groups of sealing push heads 105. Meanwhile, the bottom wall of the lower groove 107 located at the middle forming section 109 and the top arm of the lower groove 108 located at the middle forming section 109 are both provided with ribs 112 for forming the structure of the inner concave rib 54.

In use, arched beam 40 snaps between lower groove 107 and lower tongue 108 after being heated to a predetermined temperature. The middle preform section 41, the bend preform section 42 and the end preform are located at the middle section 51, the bend section 52 and the end section 53, respectively. After the upper hot air expansion die 101 and the lower hot air expansion die 102 are assembled, two groups of sealing push heads 105 are respectively in butt joint with the end parts of the two end part pre-forming sections 43, specifically, the end parts with circular cross sections in the end part pre-forming sections 43 are in butt joint communication with the sealing push heads 105. The cylinder 106 drives the piston in the sealing push head 105 to move, so that the high-pressure air source 103 and the inside of the arched beam 40 are switched on and off. When the high-pressure gas source 103 is communicated with the inside of the arched beam 40, the high-pressure gas source 103 fills the arched beam 40 with high-pressure inert gas, and the side walls of the arched beam 40 are attached to the inner side walls of the lower grooves 107 and the lower convex grooves 108 after being compressed and expanded, so that the arched beam 40 is processed into the beam main body 50, and the parts of the arched beam 40, which are contacted with the convex ribs 112, form the concave ribs 54. After the completion of the forming, the cylinder 106 is operated to block the high-pressure gas source 103 and the beam main body 50, separate the hot-air inflation upper die 101 and the hot-air inflation lower die 102, separate the seal push head 105 from the beam main body 50, and take out the beam main body 50. After the beam body 50 is cooled, the section of the end section 53 is cut off from the rectangular section to the circular section, and the required bumper is obtained.

It should be noted that during the process of inflating the high-pressure air source 103 into the arched beam 40, the cylinder 106 may be controlled to allow both ends of the arched beam 40 to communicate with the high-pressure air source 103, or only one end to communicate with the high-pressure air source 103 and the other end to seal, both of which may realize the hot air inflation of the arched beam 40. Meanwhile, as shown in fig. 12, a sealing protrusion 113 inserted into the first positioning hole 11 is provided at a side wall of the middle forming section 109. During inflation of the high pressure gas source 103 into the interior of the arched beam 40, the sealing bumps 113 seal the first pilot holes 11 on the arched beam 40 to increase gas tightness and reduce gas leakage.

In this embodiment, for the portion of the arched beam 40 located in the first positioning hole 11 (i.e., the portion where the supporting box 20 is disposed), in order to ensure that the sidewall thereof is not separated from the corrugated plate 22 on the supporting box 20 by the high pressure gas, the lower groove 107 and the lower groove 108 need to be designed in a certain shape. Specifically, after the upper hot air expansion die 101 and the lower hot air expansion die 102 are assembled, the parts of the bottom walls of the lower grooves 107 and the lower convex grooves 108 facing the circumferential direction of the first positioning holes 11 are directly in contact with the arched beam 40, so that after high-pressure air is filled, the parts at the first positioning holes 11 are not expanded, and the side walls of the arched beam 40 are not separated from the corrugated plates 22. Other portions of the arched beam 40 have a gap with the bottom walls of the lower recess 107 and the lower recess 108 that expands when filled with high pressure gas, ultimately forming a slightly concave beam body 50 at the first pilot hole 11 shown in fig. 13. The depressions here also increase the strength of the location.

Meanwhile, for the portion of the inner concave rib 54, the inner concave rib 54 located near the first positioning hole 11 (i.e. the portion where the support box 20 is disposed) is formed by pressing the convex rib 112 at the corresponding position during the process of clamping the upper hot air expansion die 101 and the lower hot air expansion die 102. To ensure that the concave ribs 54 are in a positive fit with the surface of corrugated sheet 22, they are placed in depressions in the surface of corrugated sheet 22, as shown in fig. 14. And the processing of the inner concave ribs 54 of the rest parts is realized by pressing the convex ribs 112 at corresponding positions and expanding the inflated high-pressure gas in the process of clamping the upper hot-air expansion die 101 and the lower hot-air expansion die 102.

The light bumper manufacturing method in this embodiment increases the supporting strength by the way of spot welding the supporting box 20, and compared with continuous long distance alignment welding of two main bodies, the light bumper manufacturing method has lower precision requirement, simpler process and low manufacturing cost. Meanwhile, compared with the reinforcing rib structure penetrating through the whole bumper, the strength of the part, which is close to the bending part and has high strength requirement, is increased only by adding the structure of the supporting box 20, and the overall strength is improved by adding the inner concave ribs 54 on the surface, so that the weight can be further reduced, and the weight is reduced. The first positioning hole 11 and the second positioning hole 23 facilitate positioning the position between the rectangular straight tube 10 and the support box 20 and facilitate spot welding connection.

Example 2:

the present embodiment provides a bumper including an arch-shaped body and two support boxes 20, based on the views shown in fig. 2, 9 and 14. The cross section of arch main part is hollow rectangle shape, and the arch main part includes middle part section 51, section of bending 52 and the tip section 53 that set gradually from the middle part to both ends, and every support box 20 is all including being the support piece 21 of tube-shape and welding the buckled plate 22 at support piece 21 both ends. The two support boxes 20 are symmetrically arranged in the middle section 51, the inner side wall of the middle section 51 is supported on the corrugated plate 22, and the outer side walls of the middle section 51 facing to and departing from the bending direction of the bending section 52 are both provided with concave ribs 54.

The weight can be further reduced and the weight can be reduced by increasing the strength of the portion of the bumper that is closer to the bending portion, where the strength is required to be high, by increasing the structure of the support case 20, and by increasing the strength of the inner bead 54 on the surface, as compared with the case where the reinforcing bead structure that penetrates the entire bumper is increased. Wherein, in order to facilitate the welding between the supporting box 20 and the arch-shaped main body, two groups of first positioning holes 11 are formed through the side wall of the middle section 51, and the supporting box 20 is provided with second positioning holes 23 formed through the two corrugated plates 22. When the support boxes 20 are placed in the arch-shaped body, the two sets of first positioning holes 11 are aligned with the second positioning holes 23 on the two support boxes 20, respectively. The arch body and the supporting case 20 are fixed at the first and second positioning holes 11 and 23 by spot welding.

Further, based on the illustration of fig. 14, the inwardly concave ribs 54 aligned with the corrugated plate 22 are placed in the depressions of the surface of the corrugated plate 22 to ensure the fit between the support box 20 and the arched body. At the same time, this arrangement facilitates the formation of the recessed ribs 54 without the corrugated plate 22 impeding the formation of the recessed ribs 54 when the recessed ribs 54 are machined.

Further, based on the illustration of fig. 9, the side walls of the arched body are distributed with weight-reducing holes 55 to further reduce the weight of the entire bumper.

In this embodiment, the bumper is made of BR1500HS high strength steel, and the thickness of the wall of the arched body ranges from 1.8mm to 2.5mm, preferably 2mm.

The foregoing description of the preferred embodiments of the present application is not intended to be limiting, but is intended to cover any and all modifications, equivalents, and alternatives falling within the spirit and principles of the present application.

Claims (10)

1. A method for manufacturing a lightweight bumper, comprising:

the rectangular straight pipe manufacturing step comprises the following steps: manufacturing a rectangular straight pipe (10), and penetrating two groups of first positioning holes (11) on the side wall of the rectangular straight pipe (10), wherein the two groups of first positioning holes (11) are symmetrically arranged along the extending direction of the rectangular straight pipe (10);

and a support box manufacturing step: corrugated plates (22) are welded at two ends of a cylindrical supporting piece (21) to manufacture a supporting box (20), and second positioning holes (23) penetrating through the corrugated plates (22) at two ends are formed in the supporting box (20);

and (3) manufacturing a main beam blank: placing two groups of support boxes (20) into the rectangular straight pipe (10), wherein second positioning holes (23) on the two groups of support boxes (20) are aligned with two groups of first positioning holes (11) on the rectangular straight pipe (10) respectively, and corrugated plates (22) at two ends of the support boxes (20) are supported and abutted on the inner side wall of the rectangular straight pipe (10); the support box (20) and the rectangular straight tube (10) are fixed at the first positioning hole (11) and the second positioning hole (23) through spot welding, so that the rectangular straight tube (10) and the support box (20) are combined to form a main beam blank (30) which is locally reinforced at the support box (20);

bending and forming: bending the positions, close to two ends, of the main beam blank (30) to form an arched beam (40), wherein the arched beam (40) is provided with a middle preformed section (41), a bending preformed section (42) and an end preformed section (43) from the middle to the two ends, and the supporting box (20) is positioned in the middle preformed section (41);

and (3) a hot air expansion forming step: adopting a hot gas expansion forming process to process the arched beam (40) into a beam main body (50), correspondingly forming a middle section (51) by a middle pre-forming section (41), correspondingly forming a bending section (52) by a bending pre-forming section (42), correspondingly forming an end section (53) by an end pre-forming section (43), and forming concave ribs (54) in the middle section (51) by distribution towards and away from the outer side wall of the bending direction of the bending section (52); after the beam body (50) is cooled, a desired bumper is obtained.

2. The method for manufacturing a lightweight bumper according to claim 1, wherein: in the rectangular straight tube manufacturing step, a round tube is manufactured into a rectangular straight tube (10) through a continuous rolling mode or a steel coil is manufactured into the rectangular straight tube (10) through cutting and continuous rolling combined welding modes.

3. The method for manufacturing a lightweight bumper according to claim 1, wherein: for the hot gas expansion forming process in the hot gas expansion forming step, the heated forming part of the arched beam (40) is realized by a hot gas expansion forming die (100);

the hot air expansion forming die (100) comprises a hot air expansion upper die (101), a hot air expansion lower die (102), a high-pressure air source (103), an air pipe (104), two groups of sealing push heads (105) and two groups of oil cylinders (106); the thermal expansion lower film is provided with a lower groove (107) matched with the arched beam (40), the thermal expansion upper film is provided with a lower convex groove (108) matched with the arched beam (40), and the lower groove (107) is opposite to the lower convex groove (108); the two groups of sealing push heads (105) are respectively communicated with the high-pressure air source (103) through air pipes (104), and the two groups of oil cylinders (106) are respectively communicated with the two groups of sealing push heads (105); the lower groove (107) and the lower convex groove (108) comprise a middle forming section (109), a bending forming section (110) and an end forming section (111) which are respectively arranged from the middle to the two ends so as to respectively correspond to the middle section (51), the bending section (52) and the end section (53) on the beam main body (50); the bottom wall of the lower groove (107) positioned on the middle forming section (109) and the top arm of the lower convex groove (108) positioned on the middle forming section (109) are both provided with convex ribs (112);

in the hot air forming step, two groups of sealing push heads (105) are respectively in butt joint with the ends of the two end pre-forming sections (43); the side wall of the arched beam (40) is attached to the inner side walls of the lower groove (107) and the lower convex groove (108) after being pressed and expanded, and the contact part of the arched beam (40) and the convex rib (112) forms an inner concave rib (54).

4. The method for manufacturing a lightweight bumper according to claim 3, wherein: the side wall of the middle forming section (109) is provided with a sealing lug (113) inserted into the first positioning hole (11).

5. The method for manufacturing a lightweight bumper according to claim 3, wherein: a pressing step is further arranged between the bending forming step and the hot air expansion forming step;

and (3) laminating: pressing and forming two ends of the arched beam (40) to gradually transition the cross-sectional shape of one end of the end preformed section (43) far away from the bending preformed section (42) from rectangular to circular;

in the hot air inflation forming step, the end part with a round section in the end part pre-forming section (43) is in butt joint communication with the sealing push head (105); after the beam body (50) is cooled, the portion of the end section (53) having a cross-sectional shape that gradually transitions from rectangular to circular is cut off to obtain the desired bumper.

6. The method for manufacturing a lightweight bumper according to claim 5, wherein: in the pressing step, pressing and forming the two ends of the arched beam (40) are realized through a pressing die (200);

the pressing die (200) comprises a pressing upper die (201), a pressing lower die (202) and a cylindrical mandrel (203), wherein pressing half grooves (204) corresponding to each other are formed in the pressing upper die (201) and the pressing lower die (202), and the pressing half grooves (204) on the pressing upper die (201) and the pressing half grooves (204) on the pressing lower die (202) are combined into pressing grooves (205) which are in rectangular transition from one end to the other end;

in the pressing step, a mandrel (203) is inserted into the end part of the end part pre-forming section (43) far away from the bending pre-forming section (42), and then the end part of the end part pre-forming section (43) far away from the bending pre-forming section (42) is placed into a pressing half groove (204) of a pressing lower die (202), and the pressing upper die (201) and the pressing lower die (202) are clamped to press and form the end part of the arched beam (40).

7. The method for manufacturing a lightweight bumper according to claim 1, wherein: in the rectangular straight pipe manufacturing step, the rectangular straight pipe (10) is made of BR1500HS, and the wall thickness range of the rectangular straight pipe (10) is 1.8-2.5mm;

in the step of thermal expansion forming, the heating temperature of the arched beam (40) ranges from 900 ℃ to 1000 ℃, and the pressure of the thermal expansion gas ranges from 28MPa to 32MPa.

8. A bumper beam, characterized in that: comprises an arch-shaped main body and two supporting boxes (20); the cross section of the arch main body is in a hollow rectangular shape, the arch main body comprises a middle section (51), a bending section (52) and an end section (53) which are sequentially arranged from the middle to the two ends, and each supporting box (20) comprises a cylindrical supporting piece (21) and corrugated plates (22) welded at the two ends of the supporting piece (21);

two support boxes (20) are symmetrically arranged in the middle section (51), the inner side wall of the middle section (51) is supported by the corrugated plate (22), and inner concave ribs (54) are distributed on the outer side wall of the middle section (51) in the bending direction towards and away from the bending section (52).

9. The bumper of claim 8, wherein: the side wall of the middle section (51) is provided with two groups of first positioning holes (11) in a penetrating way, the supporting box (20) is provided with second positioning holes (23) which are arranged in a penetrating way through the two corrugated plates (22), and the two groups of first positioning holes (11) are respectively aligned with the second positioning holes (23) on the two supporting boxes (20); the concave ribs (54) aligned with the corrugated plate (22) are disposed in depressions in the surface of the corrugated plate (22).

10. The bumper of claim 8, wherein: weight-reducing holes (55) are distributed on the side wall of the arched main body.