METHOD OF MANUFACTURING A VEHICLE BODY COMPONENT

Abstract

A method of manufacturing a vehicle body component as a flange-integrated tube may include step (a) of forming a pipe material having a closed cross-section with a preset shape, step (b) of cold-forming at least one flange on the pipe material forming a flange formed material, and step (c) of performing hydroforming on the flange formed material having the at least one flange by using liquid pressure.

Claims

1. A method of manufacturing a vehicle body component of a flange-integrated tube, the method comprising: step (a) of forming a pipe material having a closed cross-section with a preset shape; step (b) of cold-forming at least one flange on the pipe material to form a flange formed material; and step (c) of performing hydroforming on the flange formed material having the at least one flange by using liquid pressure to form a molded product.

2. The method of claim 1, further comprising: step (d) of heating the molded product, on which the hydroforming is performed, to a preset temperature in a heating furnace; and step (e) of rapidly cooling the heated molded product in a water tub.

3. The method of claim 2, wherein trimming and piercing are performed on the molded product.

4. The method of claim 2, wherein a strength of the molded product, which has been subjected to steps (a)-(c), is 60 K or less.

5. The method of claim 4, wherein a strength of the molded product, which has been subjected to steps (a)-(e), is 100 to 150 K.

6. The method of claim 1, wherein, in step (a), pultrusion is performed on a pipe source material subjected to pipe-making forming to have a circular closed cross-section to form the pipe material having a non-circular closed cross-section.

7. The method of claim 6, wherein, in step (a), the pipe material is bent at a preset curvature.

8. The method of claim 1, wherein, in step (a), the pipe material having a non-circular closed cross-section is formed by bending a blank material using a press forming process.

9. The method of claim 8, wherein, in step (a), the pipe material is bent at a preset curvature.

10. The method of claim 1, wherein, in step (b), the pipe material having a non-circular closed cross-section is seated on a press mold and wherein the pipe material is cold-formed by the press mold.

11. The method of claim 1, wherein, in step (c), the flange formed material is expanded and formed by preset hydraulic pressure in a hydroforming mold.

12. The method of claim 1, wherein, trimming and piercing are performed on the molded product.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Because the drawings are provided for reference to describe embodiments of the present disclosure, the technical spirit of the present disclosure should not be construed as being limited to the accompanying drawings.

[0025] FIG. 1 is a view schematically illustrating a vehicle body component manufactured by a method of manufacturing a vehicle body component according to an embodiment of the present disclosure.

[0026] FIG. 2 is a flowchart for explaining a method of manufacturing a vehicle body component according to an embodiment of the present disclosure.

[0027] FIGS. 3-9 are process diagrams for explaining a method of manufacturing a vehicle body component according to an embodiment of the present disclosure.

[0028] It should be understood that the accompanying drawings are not necessarily drawn to scale. The drawings provide a somewhat simplified representation of various features that exemplify the basic principles of the present disclosure. For example, specific design features of the present disclosure, including particular dimensions, directions, positions, and shapes, will be partially determined by the particularly intended application and use environment.

DETAILED DESCRIPTION

[0029] Hereinafter, embodiments of the present disclosure are described in detail with reference to the accompanying drawings so that those with ordinary skill in the art to which the present disclosure pertains may carry out the embodiments. However, the present disclosure may be implemented in various different ways and is not limited to the embodiments described herein.

[0030] The terms used herein are merely for the purpose of describing a specific embodiment, and not intended to limit the present disclosure. The singular expressions used herein are intended to include the plural expressions unless the context clearly dictates otherwise.

[0031] It is to be understood that the term comprise (include) and/or comprising (including) used in the present specification means that the features, the integers, the steps, the operations, the constituent elements, and/or the components are present. However, the presence or addition of one or more other features, integers, steps, operations, constituent elements, components, and/or groups thereof is not excluded.

[0032] The terms vehicle, for a vehicle, and automobile or the similar terms used in the present specification generally include vehicles. Such vehicles may include passenger vehicles, sport utility vehicles (SUVs), buses, trucks, and various commercially available vehicles. Such vehicles may also include hybrid vehicles, electric vehicles, hybrid electric vehicles, purpose built vehicles (PBVs) based on electric vehicles, hydrogen power vehicles, and other alternative fuel vehicles (e.g., fuel induced from resources other than petroleum).

[0033] Hereinafter, embodiments of the present disclosure are described in detail with reference to the accompanying drawings. When a component, device, element, or the like of the present disclosure is described as having a purpose or performing an operation, function, or the like, the component, device, or element should be considered herein as being configured to meet that purpose or perform that operation or function.

[0034] FIG. 1 is a view schematically illustrating a vehicle body component manufactured by a method of manufacturing a vehicle body component according to an embodiment of the present disclosure.

[0035] With reference to FIG. 1, the method of manufacturing a vehicle body component according to an embodiment of the present disclosure may be applied to a process of manufacturing a vehicle body component 1 that constitutes a vehicle body or part of a vehicle body. For example, the method may be applied to manufacturing a pillar assembly of a lateral part of the vehicle body.

[0036] In this case, examples of the vehicle body may include a vehicle body of a purpose-built mobility vehicle (hereinafter, referred to as a PBV).

[0037] The vehicle body of the PBV is manufactured to have a structure capable of reducing the number and weight of components and manufactured to have various shapes and sizes.

[0038] Furthermore, examples of the vehicle body component may include closed cross-section components made by joining panels by using welding or a bonding agent and may include a hybrid vehicle body with a combination of tubular closed cross-section components.

[0039] The method of manufacturing a vehicle body component according to an embodiment of the present disclosure may be applied to manufacture the tubular vehicle body component 1 applicable to the hybrid vehicle body.

[0040] Furthermore, the method of manufacturing a vehicle body component according to an embodiment of the present disclosure may be applied to manufacture a flange-integrated tube, i.e., a tubular shaped component with an integrated flange, as the vehicle body component 1. The component 1 may have at least one flange 3 integrally formed with the component, and a closed cross-section 5 having a preset shape.

[0041] However, it should not be understood that the scope of protection of the present disclosure is not limited to manufacturing of a vehicle body component. The technical spirit of the present disclosure may be applied as long as the component is a tubular component applicable to frames with various types and for various purposes in addition to the vehicle body.

[0042] In one embodiment, the vehicle body component 1 may include a bent portion 7 bent at a preset planar curvature, and at least one piercing hole 9.

[0043] FIG. 2 is a flowchart for explaining a method of manufacturing a vehicle body component according to an embodiment of the present disclosure.

[0044] With reference to FIG. 2, the method of manufacturing a vehicle body component according to an embodiment of the present disclosure may include a pipe material forming step S1, a flange forming step S2, a hydroforming step S3, a heat treatment step S4, a cooling step S5, a trimming step S6, and a piercing step S7.

[0045] In this case, the method of manufacturing a vehicle body component according to an embodiment of the present disclosure may include pre-processing steps or processes described below that are performed before the above-mentioned steps are performed.

[0046] The pre-processing steps or processes may include a process of designing the vehicle body component 1 (see FIG. 1) that is a finally molded or shaped product and may include a process of designing a layout of the forming or manufacturing facilities (e.g., molds) for manufacturing the vehicle body component 1.

[0047] In addition, the pre-processing steps or processes may include a process of performing a forming analysis on the vehicle body component 1 on the basis of the layout of the forming facilities and may include a process of manufacturing the forming facilities by designing the forming facilities, creating NC data, and performing machining on the basis of the forming analysis result.

[0048] Hereinafter, the steps of a method of manufacturing a vehicle body component according to an embodiment of the present disclosure is described in detail with reference to the accompanying drawings.

[0049] FIGS. 3-9 are process diagrams for explaining a method of manufacturing a vehicle body component according to an embodiment of the present disclosure.

[0050] With reference to FIGS. 3 and 4, the pipe material forming step S1 forms a pipe material 10 to have a closed cross-section 11 with a preset shape.

[0051] The pipe material forming step S1 is described in accordance with each embodiment. First, in one embodiment, as illustrated in FIG. 3, a pipe source material 14 having a circular closed cross-section 14a is manufactured by performing pipe-making processes on a blank material 13 (e.g., boron steel sheet) by means of a pipe-making apparatus 12.

[0052] Next, in one embodiment, the pipe material 10 having a non-circular closed cross-section 11 is manufactured by performing pultrusion on the pipe source material 14 by means of a pultrusion apparatus 15.

[0053] As illustrated in FIG. 4, in another embodiment for performing the pipe material forming step S1, the pipe material 10 having the non-circular closed cross-section 11 is manufactured by bending a blank material 17 (e.g., boron steel sheet) in a preset shape by means of a press forming facility 16.

[0054] For example, the pipe material 10 may include a polygonal closed cross-section 11.

[0055] Furthermore, other embodiments may each include a process of bending the pipe material 10 at a preset planar curvature by means of a bending machine 18.

[0056] After the above-mentioned processes, the flange forming step S2 is performed. As illustrated in FIG. 5, in the flange forming step S2, a flange formed material 20 having at least one flange 3 is primarily created by performing press forming on the pipe material 10.

[0057] In the flange forming step S2, the pipe material 10, which is seated on a lower mold of a press mold 22, is cold-formed by an upper mold, and the flange formed material 20 having at least one flange 3 may be formed from the pipe material 10.

[0058] For example, at least one flange 3 may be formed by cam forming units provided on the lower and upper molds. In the embodiment shown in the drawings, the flange formed material 20 is created having two flanges 3.

[0059] In this case, because the pipe material 10 has the polygonal closed cross-section 11, the seating properties of the press mold 22 may be ensured.

[0060] Next, the hydroforming step S3 is performed. As illustrated in FIG. 6, in the hydroforming step S3, a molded product 30 having at least one flange 3 and a closed cross-section 5 with a preset shape is manufactured by performing hydroforming on the flange formed material 20 with a liquid pressure.

[0061] In the hydroforming step S3, the flange formed material 20 is seated on a hydroforming mold 31 and may be expanded and formed by a hydraulic pressure.

[0062] As is well known to those of ordinary skill in the art, the hydroforming mold 31 may include a lower mold, an upper mold, two pressure intensifiers, and a punch.

[0063] In this case, the molded product 30, which is manufactured by being subjected to the pipe material forming step S1, the flange forming step S2, and the hydroforming step S3, has a ferrite structure. The strength of the molded product 30 may be 60 K or less.

[0064] Meanwhile, a method of manufacturing a vehicle body component according to and embodiment of the present disclosure performs the heat treatment step S4 and the cooling step S5, which are described below, so that the molded product 30 has a martensite structure with high strength.

[0065] As illustrated in FIG. 7, in the heat treatment step S4, the molded product 30 is heated to a preset temperature in a heating furnace 41.

[0066] In this case, the molded product 30 may be loaded into the heating furnace 41 by a robot. Further, the heating furnace 41 includes a heating furnace base 43 on which the molded product 30 is seated. As an example, the heating furnace base 43 may be implemented as a drawer type structure.

[0067] Furthermore, the heating furnace 41 may heat the molded product 30 to a high temperature (e.g., 900 C. or more) equal to or higher than a transformation point temperature by using heat generated by a plurality of heaters 45.

[0068] Therefore, a metal structure of the molded product 30 may change from a ferrite structure to an austenite structure.

[0069] Next, as illustrated in FIG. 8, in the cooling step S5, the molded product 30, which has been heated to a high temperature, is rapidly cooled in a water tub 51.

[0070] In this case, the molded product 30 may be loaded into the water tub 51 by a robot. The water tub 51 includes a water tub base 53 that may move in an upward/downward direction. As an example, the water tub base 53 may be implemented as a drawer type structure.

[0071] Further, in a state in which the molded product 30 is seated on the water tub base 53, the water tub base 53 moves downward, such that the molded product 30 may be cooled directly by a coolant in the water tub 51.

[0072] Therefore, as the molded product 30 is rapidly cooled in the water tub 51, the molded product 30 has a martensite structure of about 100 to 150 K.

[0073] The molded product 30 manufactured as described above is subjected to the trimming step S6 and the piercing step S7, such that the vehicle body component 1, i.e., the finally molded product may be manufactured, as illustrated in FIG. 1.

[0074] In this case, as illustrated in FIG. 9, in the trimming step S6, an unnecessary portion 30a of the molded product 30 is removed or trimmed by using laser beams LB.

[0075] Further, as illustrated in FIG. 9, in the piercing step S7, at least one piercing hole 9 is formed in the molded product 30 by using the laser beams LB.

[0076] Hereinafter, the effect of a method of manufacturing a vehicle body component according to an embodiment of the present disclosure is described with reference to a comparison with a comparative example.

[0077] First, a method of manufacturing a flange-integrated tube according to the comparative example includes a process of forming a flange in a state in which a pipe material having a circular cross-section is electrically heated in a single mold, performing hydroforming by using a pneumatic pressure, and cooling the flange by using a coolant flowing along a cooling channel. This method of manufacturing the flange-integrated tube by the above-mentioned processes is typically referred to as a STAF process method in the art.

[0078] In contrast, the method of manufacturing a vehicle body component according to the embodiment of the present disclosure may form at least one flange 3 by cold-forming the pipe material 10 having the non-circular closed cross-section 11.

[0079] Therefore, because a method of manufacturing a vehicle body component according to an embodiment of the present disclosure cold-forms at least one flange 3 on the pipe material 10 having the non-circular closed cross-section 11, it is possible to ensure the mold seating properties of the pipe material 10, unlike the comparative example that forms the flange on the pipe material having a circular cross-section.

[0080] In addition, because the comparative example forms the flange by electrically heating the pipe material having a circular cross-section, non-uniform electrical application to the pipe material may be caused by a constraint such as a bending curvature numerical value of the pipe material. Therefore, because it is impossible to electrically heat the overall pipe, a degree of design freedom of the molded product may deteriorate.

[0081] Furthermore, a method of manufacturing a vehicle body component according to an embodiment of the present disclosure performs the hydroforming on the flange formed material 20 by the hydroforming mold 31 by using hydraulic pressure. However, the comparative example performs hydroforming on the material having the flange by using pneumatic pressure.

[0082] Therefore, because the hydraulic pressure is about at least 10 times higher than the pneumatic pressure, the method of manufacturing a vehicle body component according to the embodiment of the present disclosure may implement a corner portion 6 (see FIG. 6) of the vehicle body component 1 in accordance with a designed numerical value. In contrast, the comparative example cannot implement a shape of a final product because of a lack of a pressing force of a material.

[0083] If hydroforming is performed by hydraulic pressure in the comparative example, the electrically heated material is rapidly cooled, and the strength of the material increases, which makes it impossible to implement a shape of the final product.

[0084] While embodiments of the present disclosure have been described above, the present disclosure is not limited thereto. Various modifications can be made and carried out within the scope of the claims, the detailed description of the disclosure, and the accompanying drawings, and also fall within the scope of the present disclosure.

DESCRIPTION OF SYMBOLS

[0085] 1: Vehicle body component 3: Flange [0086] 5, 11, 14a: Closed cross-section 7: Bent portion [0087] 9: Piercing hole 10: Pipe material [0088] 12: Pipe-making apparatus 14: Pipe source material [0089] 15: Pultrusion apparatus 16: Press forming facility [0090] 18: Bending machine 20: Flange forming material [0091] 22: Press mold 30: Molded product [0092] 30a: Trimming portion 31: Hydroforming mold [0093] 41: Heating furnace 43: Heating furnace base [0094] 45: Heater 51: Water tub [0095] 53: Water tub base LB: Laser beam