A fender front retainer flange forming method and apparatus

Abstract

The application discloses a fender front protection flanging forming method and device, and belongs to the technical field of automobile covering part cold stamping die design and manufacturing. The method comprises the following steps: obtaining product geometric characteristics of a fender front protection flanging area; constructing a flanging tool body surface structure based on the product geometric characteristics, including a short transition surface corresponding to a lamp tip side and an extension surface corresponding to a wheel arc side, and the length of the short transition surface is less than the length of the extension surface; installing the flanging tool body to a stamping die; positioning a plate and driving a pressing component to press down to fix the plate; driving the flanging tool body to perform one-time flanging forming, and the short transition surface and the extension surface respectively constrain the material flow on both sides; and taking out the workpiece. Through the synergistic effect of product side geometric characteristic optimization and flanging tool body differential surface structure design, the flanging forming is completed in a single process, the number of processes and the cost of the die are reduced, and the occurrence probability of defects such as A surface arching, flanging material stacking and local material chasing is reduced.

Description

Technical Field

[0001] This invention relates to the field of automotive body panel cold stamping die design and manufacturing technology, specifically to a fender front bumper flanging forming method and apparatus. Background Technology

[0002] As an important component of automotive exterior panels, the fender typically has a long flange boundary in its front bumper flange area, accompanied by a double-step feature. The flange forming quality in this area directly affects the overall vehicle appearance quality and assembly precision, making it a key aspect of the fender stamping process design.

[0003] In traditional stamping processes, the fender area of ​​the front fender typically employs a multi-stage, step-by-step forming scheme. Specifically, a shallow fender is first performed in the first stage to form the characteristic rounded corners of surface A; subsequently, a secondary fender is performed in the second or even third stage to achieve the fender height required by the product design. While this multi-stage, step-by-step forming method can ensure forming quality to a certain extent and avoid excessive material flow during a single deformation, it also brings a series of problems. First, the multi-stage scheme requires more stamping dies, each of which needs to be independently designed, processed, and debugged, leading to a significant increase in die manufacturing costs. Second, multi-stage forming requires more press stations and production time, reducing production efficiency and increasing the unit cost of the part. Third, there is the issue of positioning datum conversion between multiple stages; each stage conversion may introduce positioning errors, which accumulate and affect the final forming accuracy.

[0004] To reduce costs, those skilled in the art have attempted a single-process flanging solution, completing the entire flanging process in a single stamping operation. However, in practical applications, single-process flanging faces numerous technical challenges. On one hand, due to the long flanging boundary and the presence of two stepped features, the material flow during flanging is complex. Without effective constraints, the flanging area on side A is prone to upward arching deformation, affecting the flatness of the surface. On the other hand, material stacking is prone to occur on the inner side of the flanging, especially at corners and step transition areas, where material accumulation leads to abnormally increased local thickness and even wrinkling defects. In addition, the problem of severe local material rushing is also prominent. The material flows too quickly in some areas and not enough in others, resulting in uneven distribution of forming stress and affecting the dimensional stability of the part.

[0005] A key reason for the aforementioned problems is the lack of a unified and stable design basis for the surface design of flanging tools. Currently, the surface parameters of flanging tools are mostly determined based on the personal experience of designers. Different designers may provide significantly different solutions for similar problems, leading to inconsistent solutions and large fluctuations in design quality. Furthermore, due to the lack of systematic design rules and parametric methods, the design of flanging tools for new car models or new parts often requires multiple rounds of trial molding and repeated adjustments to meet quality requirements. This results in numerous on-site trial moldings, long debugging cycles, and the difficulty in systematically reusing the accumulated experience.

[0006] Furthermore, there is often a lack of coordination between the geometric design of the product and the surface design of the flanging tool. The product design phase often focuses only on the functional and aesthetic requirements of the final product, with little consideration for the manufacturability of stamping; the mold design phase, on the other hand, performs process compensation based on a fixed product structure, making it difficult to improve material flow conditions from the source. This disconnect between product design and process design further increases the difficulty of single-stage flanging.

[0007] Therefore, there is an urgent need in this field for a technical solution that can complete the fender front flange forming in a single process while ensuring forming quality. This solution should be able to effectively constrain material flow, reduce the probability of defects such as arching on the A-side, flange stacking, and local material rushing, and have a reusable and adjustable parametric design basis. Summary of the Invention

[0008] To overcome the above deficiencies, this invention proposes a fender front guard flanging forming method and device, which solves the problem of high mold cost caused by multi-process flanging, as well as the quality problems such as A-side rounded corner arching, flanging material stacking and serious material rushing that occur in single-process flanging. Furthermore, it solves the problems of flanging tool body design relying on experience, repeated experiments, long debugging cycle, inconsistent solutions and low design efficiency.

[0009] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for forming a flanged front fender, comprising: Obtain the product geometric features of the fender flange area; Based on the geometric features of the product, a surface structure for the flanging tool body is constructed, such that the surface structure includes a short transition surface corresponding to the two-layer step features on the lamp tip side, and an extended surface corresponding to the two-layer step features on the wheel arc side, and the length of the short transition surface is less than the length of the extended surface. The flanging tool body is installed onto the stamping die, so that the short transition surface corresponds to the position of the second-layer step area on the lamp tip side, and the extended surface corresponds to the position of the second-layer step area on the wheel arc side. The sheet material to be formed is positioned in the lower die positioning area of ​​the stamping die, and the pressing component is driven to press down to fix the sheet material to be formed; The flanging tool body is driven to perform a one-time flanging forming of the front guard flanging area; within the same mold, the material flow on the lamp tip side is constrained by the short transition surface, and the material flow on the wheel arc side is constrained by the extended surface; Demold and remove the part to obtain a fender with front guard flange features.

[0010] Optionally, obtaining the product geometric features of the fender front bumper flange area includes: identifying the short side segment and the long side segment in the fender front bumper flange area; A transition fillet is provided at the junction of the short side segment and the long side segment, and a step fillet is provided at the second-level step feature, with the radius of the transition fillet being larger than the radius of the step fillet; The product geometric features include the transition fillet located at the junction of the short and long sides of the front bumper flange, and the step fillet located at the second-level step feature.

[0011] Optionally, constructing the surface structure of the flanging tool body according to the product's geometric features includes: determining the start and end positions of the two-layer step features on the lamp tip side; designing the flanging tool body surface to be a single-layer product surface that separates from the two-layer step structure and transitions to the fender body after the end position of the two-layer step features; and setting a transition connection surface between the end position of the two-layer step features and the single-layer product surface.

[0012] Optionally, the transition connection surface is formed by processing a local transition surface, a small radius connection surface, or a polygonal buffer surface.

[0013] Optionally, the construction of the extended profile includes: determining the initial position of the two-layer step feature on the wheel arc side; extending the extended profile from the initial position along the flange direction to the flange rounded corner on the wheel arc side; and setting a connecting profile between the end formed after the extension of the extended profile and the flange rounded corner on the wheel arc side.

[0014] Optionally, the connecting surface is formed by processing a transition surface and connecting it to the flange fillet.

[0015] Optionally, the flanging tool body is provided with a partial rounded corner at a position corresponding to the rounded corner of the second step, and the radius of the partial rounded corner matches the radius of the rounded corner of the second step of the product; when the flanging tool body is driven to perform one-time flanging forming, the flow state of the material is constrained during the flanging process through the combined action of the partial rounded corner and the rounded corner of the second step of the product.

[0016] Optionally, before the pressure component is pressed down, the pressing gap of the pressure component is set according to the thickness of the sheet material.

[0017] Secondly, the present invention provides a fender front bumper flanging forming device, including an upper mold, a lower mold, a pressing component, a flanging insert, a guiding mechanism, and a limiting mechanism. The flanging insert includes a short transition surface corresponding to the two-layer step feature on the lamp tip side and an extended surface corresponding to the two-layer step feature on the wheel arch side. The length of the short transition surface is less than the length of the extended surface. The short transition surface is used to detach from the two-layer step structure after the termination position of the two-layer step feature on the lamp tip side and transition to the first-layer product surface of the fender body. The extended surface is used to extend the two-layer step feature along the flanging direction to the rounded corner of the wheel arch side flanging.

[0018] Optionally, the flanged insert has a partial rounded corner at a position corresponding to the rounded corner of the second step, and the radius of the partial rounded corner matches the radius of the rounded corner of the second step of the product.

[0019] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a method and apparatus for forming a fender front bumper flange. By setting a larger transition radius at the short and long sides of the flange and a smaller radius at the second-layer step radius on the product side, favorable conditions are provided for material flow from the perspective of product geometry. The larger transition radius can reduce local material accumulation and flange overlap caused by an excessively small transition radius, while also constraining the short side area, making the material rushing trend during the flange process more gradual. The smaller second-layer step radius can constrain the material flow speed during the flange process, avoiding excessively rapid material extrusion after the outer structural line at the second-layer step comes into contact with the material, thereby reducing the tendency for material to accumulate towards the A-side radius.

[0020] This invention employs a differentiated surface design on the flanging tool body, setting short transition surfaces and extended surfaces respectively to address the different material flow characteristics of the lamp tip side and the wheel arc side. The length of the short transition surface is shorter than the length of the extended surface, achieving differentiated constraints on material flow in different areas. The short transition surface on the lamp tip side shortens the constraint path of the local second-layer step on material flow, helping to reduce the upward arching degree of the large rounded corner of the A-side in the lamp tip area. The extended surface on the wheel arc side lengthens the local material flow path, which can disperse the material accumulation tendency and help alleviate the upward arching problem of the A-side of the wheel arc side flanging.

[0021] This invention combines product-side geometric feature optimization with differentiated surface design of the flanging tool body, completing the flanging forming of the front fender area in a single process. This reduces the number of stamping processes required, lowers mold manufacturing costs, and reduces production cycle time. Simultaneously, by effectively constraining material flow, it reduces the probability of defects such as A-surface arching, flanging overlap, and localized material rushing, thereby improving the forming quality and yield of the parts.

[0022] This invention establishes a correspondence between the local surface design rules of the flanging tool body and the local geometric parameters of the product, forming a parametric design method. This reduces reliance on personal experience, facilitates unified design schemes, reduces the number of trial moldings, shortens the debugging cycle, and enables the systematic accumulation and transfer of design experience for similar parts, thereby improving design and debugging efficiency. Attached Figure Description

[0023] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0024] Figure 1 This is a schematic flowchart of the fender front guard forming method in this invention; Figure 2 This is a schematic diagram of the flanged inlay surface structure in this invention; Figure 3 This is a schematic diagram showing the location of the flanged area of ​​the front fender in this invention; Figure 4 This is a schematic diagram of the product geometry of the flanged area of ​​the front fender in this invention; Figure 5 This is a schematic diagram of the outer side of the front fender flange area in the present invention; Figure 6 This is a cross-sectional schematic diagram of the flanging forming device in this invention; Figure 7 This is a schematic diagram of the lower mold of the flanging forming device in this invention; Figure 8 This is a schematic diagram of the upper mold structure of the flanging forming device in this invention.

[0025] In the diagram: 1-Short side of front bumper flange, 2-Long side of front bumper flange, 3-Transition rounded corner, 4-Rounded corner of second-layer step, 5-Feature of second-layer step on the lamp tip side, 6-Short transition surface, 7-First-layer product surface of the fender body, 8-Feature of second-layer step on the wheel arch side, 9-Extended surface, 10-Rounded corner of wheel arch side flange, 11-Upper mold, 12-Lower mold, 13-Pressure material component, 14-Flanged insert, 15-Guiding mechanism, 16-Limiting mechanism, 17-Partial rounded corner, 18-Transition connection surface, 19-Seamless connection surface. Detailed Implementation

[0026] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of the present invention and are therefore merely examples, and should not be construed as limiting the scope of protection of the present invention.

[0027] It should be noted that, unless otherwise stated, the technical or scientific terms used in this application should have the ordinary meaning as understood by those skilled in the art to which this invention pertains.

[0028] This invention provides a method and apparatus for forming the front fender flange of a fender. The embodiments of this invention are described below with reference to the accompanying drawings.

[0029] Example 1: As Figure 1 As shown, the fender front bumper flanging forming method provided in Embodiment 1 of the present invention specifically includes the following steps: Step S101: Obtain the product geometric features of the fender front bumper flange area.

[0030] like Figure 4 As shown, the fender front bumper flange area typically includes a short side 1 and a long side 2, connected by a transition fillet 3. This area also features a double-step characteristic, with a double-step fillet 4 at the double-step location. In this step, the product model is first analyzed to identify the short and long side segments in the fender flange area and determine their intersection position. Then, a transition fillet 3 is set at the intersection of the short and long side segments, and a step fillet 4 is set at the double-step characteristic, with the radius of the transition fillet 3 being larger than the radius of the step fillet 4. The product geometric features include the transition fillet 3 located at the intersection of the short and long sides of the fender flange, and the step fillet 4 located at the double-step characteristic.

[0031] The transition fillet 3 features a larger radius design. Its purpose is to provide a smooth transition space for material flow from the short side to the long side, preventing rapid material accumulation at the corner due to an excessively small transition fillet. During the flanging process, material flows from the short side to the long side. The larger transition fillet guides the material to gradually diffuse, reducing localized material accumulation and thus lowering the probability of material stacking during flanging. Simultaneously, the larger transition fillet provides some constraint to the short side area, smoothing the material flow during flanging and helping to reduce the risk of defects on surface A.

[0032] The second-layer step fillet 4 employs a smaller radius design to constrain the material flow velocity during the flanging process. In the second-layer step area, when the outer structural line contacts the material, if the step fillet is too large, the material tends to flow rapidly along the step surface and accumulate in the A-side fillet area, causing the A-side fillet to arch upwards. By setting a smaller second-layer step fillet, the flow resistance of the material at the step can be increased, the material flow velocity can be slowed down, and excessively rapid material extrusion can be avoided, thereby reducing the tendency for material to accumulate in the A-side fillet. The smaller second-layer step fillet, as a local material flow constraint feature, works in conjunction with the subsequent flanging tool body profile design to improve the forming stability of the second-layer step area.

[0033] Step S102: Based on the product's geometric features, construct the surface structure of the flanging tool body, such that the surface structure includes a short transition surface corresponding to the two-layer step feature on the lamp tip side and an extended surface corresponding to the two-layer step feature on the wheel arc side, and the length of the short transition surface is less than the length of the extended surface.

[0034] Based on the obtained product geometry, this step involves differentiated construction of the flange tool's profile. The profile structure includes a short transition profile 6 corresponding to the second-layer step feature 5 on the lamp tip side, and an extended profile 9 corresponding to the second-layer step feature 8 on the wheel arc side, with the length of the short transition profile 6 being less than the length of the extended profile 9. The difference in length between the short transition profile and the extended profile is determined based on the different material flow characteristics of the lamp tip side and the wheel arc side, achieving differentiated constraints on material flow in different areas through differentiated profile lengths.

[0035] like Figure 2 As shown, the construction process of the short transition surface 6 is as follows: First, the start and end positions of the second-layer step feature 5 on the lamp tip side are determined, and the extension range of the second-layer step on the lamp tip side is clarified; then, after the end position of the second-layer step feature 5, the flange tool body surface is designed to detach from the second-layer step structure and transition to the first-layer product surface 7 of the fender body; finally, a transition connection surface 18 is set between the end position of the second-layer step feature 5 and the first-layer product surface 7. The transition connection surface 18 is formed by processing a local transition curved surface, a small radius connection surface, or a polygonal buffer surface, and the specific form can be selected according to processing convenience and adjustment requirements. The core feature of the short transition surface 6 is that the second-layer step structure quickly transitions to the first-layer product surface of the fender body after terminating on the lamp tip side, thereby shortening the constraint path of the local second-layer step on the material flow, reducing the continuous squeezing effect of the second-layer step on the material in the lamp tip area, and helping to reduce the upward arching degree of the large rounded corner of the A-side in the lamp tip area.

[0036] like Figure 2 As shown, the construction process of the extended surface 9 is as follows: First, the initial position of the two-layer step feature 8 on the wheel arc side is determined, clarifying the starting position of the two-layer step on the wheel arc side; then, the extended surface 9 is extended from the initial position along the flange direction to the flange fillet 10 on the wheel arc side, giving the two-layer step structure a longer extension length on the wheel arc side; finally, a connecting surface 19 is set between the end formed after the extension of the extended surface 9 and the flange fillet 10 on the wheel arc side. The connecting surface 19 is formed by processing the transition surface and connecting it smoothly to the flange fillet to ensure the smoothness of the surface transition. The core feature of the extended surface 9 is that the two-layer step structure extends to the flange fillet on the wheel arc side, thereby extending the local material flow path, allowing the material to gradually deform and flow along a longer path, which can disperse the tendency of material aggregation, avoid excessive concentration of material in local areas, and help alleviate the upward arching problem of the flange A surface on the wheel arc side.

[0037] Furthermore, the flanging tool body has a local fillet 17 at a position corresponding to the fillet of the second-layer step, and the radius of the local fillet 17 matches the radius of the fillet 4 of the second-layer step on the product. Through the combined action of the local fillet 17 and the fillet 4 of the second-layer step on the product, the flow state of the material during the flanging process can be further constrained, reducing the degree of local stress concentration and minimizing the risk of material accumulation at the step corner. The specific value of the local fillet can be finely adjusted in an engineering manner, taking into account factors such as sheet thickness, material strength, and forming depth, to adapt to the forming requirements under different product and material conditions.

[0038] Step S103: Install the flanging tool body onto the stamping die, so that the short transition surface corresponds to the position of the second-layer step area on the lamp tip side, and the extended surface corresponds to the position of the second-layer step area on the wheel arc side.

[0039] like Figure 6 As shown, the fender front bumper flanging forming device mainly includes an upper mold 11, a lower mold 12, a pressing component 13, a flanging insert 14, a guiding mechanism 15, and a limiting mechanism 16. The flanging insert 14 is the aforementioned flanging tool body, on which a short transition surface 6 and an extended surface 9 are machined. During installation, the flanging insert 14 is installed to the corresponding position of the upper mold 11, so that the short transition surface 6 corresponds to the position of the second-layer step area on the lamp tip side, and the extended surface 9 corresponds to the position of the second-layer step area on the wheel arc side, ensuring that the surface positions accurately correspond to the product feature positions.

[0040] The upper die 11 is used to drive the flanging action, moving up and down with the press slide; such as Figure 7 As shown, the lower die 12 is used to support and position the workpiece and is fixed to the press table; the blank holder 13 is used to fix the sheet metal and control the material flow, usually by providing blank holder force through an elastic element; the flange insert 14 is used to form a local flange profile and is the core component for achieving differentiated material flow constraints; the guide mechanism 15 is used to ensure the closing accuracy of the upper and lower dies, usually by adopting a guide post and guide sleeve structure; the limiting mechanism 16 is used to control the forming stroke and ensure that the flange height meets the design requirements. The basic structure and function of the above components are all conventional structures in automotive body panel stamping dies, which can provide a stable assembly and motion basis for the local profile design of this invention.

[0041] Step S104: Position the sheet material to be formed in the lower die positioning area of ​​the stamping die, and drive the pressing component to press down to fix the sheet material to be formed.

[0042] like Figure 8As shown, before the flanging process begins, the incoming material or initial blank processed in the previous step is placed in the positioning area of ​​the lower die 12. The positioning area of ​​the lower die is equipped with positioning elements such as positioning pins and positioning blocks to limit the displacement of the sheet metal in the horizontal plane and ensure the accurate position of the sheet metal in the die. The positioning reference is usually selected from the formed features or process holes on the part to ensure positioning accuracy and consistency of the reference between the preceding and following processes.

[0043] Before the pressing component is driven down, the pressing gap of the pressing component is set according to the sheet thickness. The setting of the pressing gap directly affects the flow state of the sheet during the flanging process. If the gap is too large, the sheet is prone to instability and wrinkling; if the gap is too small, the material flow resistance is too large, leading to forming difficulties. Setting the pressing gap according to the sheet thickness ensures that the sheet is in an appropriate constrained state during the flanging process, guaranteeing the stability of the sheet while allowing the material to flow within a reasonable range.

[0044] After the sheet metal is positioned, the upper die 11 moves downward with the press slide, and the pressing component 13 first contacts the sheet metal and continues to press down to fix the sheet metal to be formed. The pressing component 13 presses the sheet metal onto the profile surface of the lower die 12 through the pressing force provided by the elastic element, preventing the sheet metal from shifting or arching during the flanging process.

[0045] Step S105: Drive the flanging tool body to perform a one-time flanging forming of the front guard flanging area.

[0046] After the pressing component completes the sheet metal fixing, the upper mold 11 continues to move downwards, and the flanging insert 14 moves downwards with the upper mold 11 to perform flanging forming on the front guard flanging area. In the same mold cycle, the short transition surface 6 and the extended surface 9 participate in the forming simultaneously. The short transition surface 6 constrains the material flow on the lamp tip side, and the extended surface 9 constrains the material flow on the wheel arc side.

[0047] The short transition surface 6 provides a shorter constraint path for material flow on the lamp tip side. This is because the curvature change in the lamp tip side region is significant, resulting in a shorter material flow path. If the second-layer step constraint is too long, it can easily lead to excessive material compression and accumulation in the large rounded corner area of ​​surface A. Therefore, a short transition surface is used to shorten the constraint path. The extended surface 9 provides a longer constraint path for material flow on the wheel arc side. This is because the flange boundary in the wheel arc side region is longer, resulting in a longer material flow distance. If the constraint path is insufficient, material can easily accumulate midway. Therefore, an extended surface is used to lengthen the constraint path and disperse the tendency for material accumulation. The length of the short transition surface is less than the length of the extended surface, which is determined based on the differences in material flow characteristics on both sides.

[0048] During the flanging process, the local fillet 17 on the flanging insert 14 works in conjunction with the fillet 4 of the second-layer step on the product to provide additional constraints on the material flow in the step area. The local fillet 17 makes the material flow more smoothly when passing through the step corner, reducing stress concentration and material accumulation. At the same time, the smaller fillet 4 of the second-layer step on the product side works synergistically with the matching local fillet 17 on the tool body side to jointly control the material flow speed and deformation distribution in the step area.

[0049] Step S106: Demold and remove the part to obtain a fender with front guard flange features.

[0050] After the flanging is completed, the upper die 11 moves upward with the press slide, and the flanging insert 14 and the pressing component 13 sequentially detach from the part. Subsequently, the formed fender is removed from the lower die 12 by the unloading device, completing the entire single-operation flanging process. After the part is removed, it can be inspected for quality to confirm whether the flatness of surface A, the flanging height, the step shape, etc., meet the product requirements.

[0051] The single-process flanging forming method described above achieves the flanging forming effect that originally required multiple processes in a single mold through the synergistic effect of optimizing the geometric features of the product side and the differentiated surface design of the flanging tool body. This reduces the number of processes and molds, while ensuring forming quality through effective constraints on material flow.

[0052] Example 2: Taking the front bumper area of ​​a car fender as an example, this area has a long flange boundary and a two-tiered step feature. When using the technical solution of this invention, the transition fillet between the short and long sides is set to a larger fillet, and the fillet of the two-tiered step is set to a smaller fillet; the surface structure of the flange tool body is constructed based on the product's geometric features, so that the surface structure includes a short transition surface corresponding to the two-tiered step feature on the lamp tip side and an extended surface corresponding to the two-tiered step feature on the wheel arch side, and the length of the short transition surface is less than the length of the extended surface; the short transition surface on the lamp tip side detaches from the two-tiered step structure after the two-tiered step feature ends and transitions to the first-tier product surface of the fender body, and a transition connection surface is provided between the two; the extended surface on the wheel arch side extends along the flange direction to the flange fillet on the wheel arch side, and a connecting surface is provided between the extension end and the flange fillet; the flange tool body has a local fillet at the position corresponding to the two-tiered step fillet, and the radius of the local fillet matches the radius of the two-tiered step fillet of the product.

[0053] Install the flanging tool body onto the stamping die, aligning the short transition surface with the position of the second-layer step area on the lamp tip side and the extended surface with the position of the second-layer step area on the wheel arc side; set the pressure gap of the pressure component according to the sheet metal thickness; position the sheet metal to be formed in the lower die positioning area and drive the pressure component to press down to fix the sheet metal; drive the flanging tool body to perform one-time flanging forming of the front guard flanging area, constraining the material flow on the lamp tip side through the short transition surface and constraining the material flow on the wheel arc side through the extended surface in the same die cycle; demold and remove the part to obtain a fender with front guard flanging features.

[0054] After the flanging process is completed in a single cycle, the material flow is relatively stable, and the arching and stacking phenomena on surface A are suppressed. This also reduces the pre-flanging and secondary flanging processes required in traditional multi-process solutions. This embodiment demonstrates that this solution can reduce the number of processes and improve forming stability while ensuring local appearance quality.

[0055] Example 3: For the front bumper area of ​​the fender with a smaller sheet thickness and more pronounced local curvature changes, the local fillet radius can be further adapted to a smaller engineering range. The lengths of the short transition surface on the lamp tip side and the extended surface on the wheel arch side can be differentiated according to the sheet metal flow trend, maintaining a relationship where the short transition surface length is less than the extended surface length. This method can further reduce concentrated deformation of local materials during the flanging process, decrease the risk of local bulging and edge wrinkling, and improve adaptability under different vehicle model conditions. This example illustrates that this solution is not limited to single vehicle model parameters but can be parametrically transferred according to conventional stamping design rules.

[0056] The above are merely embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of the claims of the present invention pending approval.

Claims

1. A method for forming a flanged front guard of a fender, characterized in that, include: Obtain the product geometric features of the fender flange area; Based on the geometric features of the product, a surface structure for the flanging tool body is constructed, such that the surface structure includes a short transition surface corresponding to the two-layer step features on the lamp tip side, and an extended surface corresponding to the two-layer step features on the wheel arc side, and the length of the short transition surface is less than the length of the extended surface. Install the flanging tool body onto the stamping die, so that the short transition surface corresponds to the position of the second-layer step area on the lamp tip side, and the extended surface corresponds to the position of the second-layer step area on the wheel arc side. The sheet material to be formed is positioned in the lower die positioning area of ​​the stamping die, and the pressing component is driven to press down to fix the sheet material to be formed; The flanging tool body is driven to perform a one-time flanging forming of the front guard flanging area; within the same mold, the material flow on the lamp tip side is constrained by the short transition surface, and the material flow on the wheel arc side is constrained by the extended surface; Demold and remove the part to obtain a fender with front guard flange features.

2. The method according to claim 1, characterized in that, The process of obtaining the product geometric features of the fender front bumper flange area includes: identifying the short and long side segments in the fender front bumper flange area; A transition fillet is provided at the junction of the short side segment and the long side segment, and a step fillet is provided at the second-level step feature, with the radius of the transition fillet being larger than the radius of the step fillet; The product geometric features include the transition fillet located at the junction of the short and long sides of the front bumper flange, and the step fillet located at the second-level step feature.

3. The method according to claim 1, characterized in that, The process of constructing the surface structure of the flanging tool body based on the product's geometric features includes: determining the start and end positions of the two-layer step features on the lamp tip side; designing the surface of the flanging tool body to be a single-layer product surface that separates from the two-layer step structure and transitions to the fender body after the end position of the two-layer step features; and setting a transition connection surface between the end position of the two-layer step features and the single-layer product surface.

4. The method according to claim 3, characterized in that, The transition connection surface is formed by processing a local transition surface, a small radius connection surface, or a polygonal buffer surface.

5. The method according to claim 1, characterized in that, The construction of the extended surface includes: determining the initial position of the two-layer step feature on the wheel arc side; extending the extended surface from the initial position along the flange direction to the flange rounded corner on the wheel arc side; and setting a connecting surface between the end formed after the extension of the extended surface and the flange rounded corner on the wheel arc side.

6. The method according to claim 5, characterized in that, The connecting surface is formed by processing the transition surface and connecting it to the flanged rounded corner.

7. The method according to claim 1, characterized in that, The flanging tool has a partial rounded corner at a position corresponding to the rounded corner of the second step. The radius of the partial rounded corner matches the radius of the rounded corner of the second step of the product. When the flanging tool is driven to perform a one-time flanging forming, the flow state of the material is constrained during the flanging process through the combined action of the partial rounded corner and the rounded corner of the second step of the product.

8. The method according to claim 1, characterized in that, Before the pressure component is pressed down, the pressing gap of the pressure component is set according to the thickness of the sheet material.

9. A fender front bumper flanging forming device, comprising an upper mold, a lower mold, a pressing component, a flanging insert, a guiding mechanism, and a limiting mechanism, characterized in that, The flanged insert includes a short transition surface corresponding to the two-layer step feature on the lamp tip side and an extended surface corresponding to the two-layer step feature on the wheel arch side. The length of the short transition surface is less than the length of the extended surface. The short transition surface is used to detach from the two-layer step structure after the termination position of the two-layer step feature on the lamp tip side and transition to the first-layer product surface of the fender body. The extended surface is used to extend the two-layer step feature along the flanged direction to the rounded corner of the flange on the wheel arch side.

10. The apparatus according to claim 9, characterized in that, The flanged inlay has a partial rounded corner at a position corresponding to the rounded corner of the second step, and the radius of the partial rounded corner matches the radius of the rounded corner of the second step of the product.

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