Automobile roof outer plate sunroof negative angle flanging compound die and forming method thereof

Abstract

This invention discloses a composite mold for flanging the negative corner of a car sunroof outer panel and its forming method. The composite mold includes an upper mold body, a lower mold body, an upper mold guide plate, a sliding positioning structure, and an outer flanging insert and an inner flanging insert for shaping the negative corner of the sunroof. The inner flanging insert is fixed on the sliding positioning structure, and the outer flanging insert is slidably disposed within the sliding positioning structure. The sliding positioning structure is slidably disposed on the lower mold body, and the upper mold guide plate is disposed at the lower part of the upper mold body. The upper mold guide plate is a bidirectional guide plate structure that can simultaneously drive the sliding positioning structure and the outer flanging insert. After the lower mold guide plate contacts the outer flanging insert, it pushes the outer flanging insert to generate a movement trajectory in the Y direction. At the same time, the bidirectional upper mold guide plate contacts the sliding positioning structure and generates a movement trajectory opposite to that of the outer flanging insert in the Y direction. This allows the inner flanging insert and the outer flanging insert to cooperate with each other to perform shaping operations on the negative corner flanging area of ​​the sunroof, ensuring product quality stability.

Description

Technical Field

[0001] This invention relates to the field of automotive mold technology, and in particular to a composite mold for the negative angle flange of the sunroof outer panel of an automobile roof and its forming method. Background Technology

[0002] In today's booming automotive industry, consumer demands for automobiles are becoming increasingly diversified and their standards are constantly rising. To meet the diverse needs of different consumers, automakers are continuously increasing their efforts in model development, launching more and more new models. The continuous development of new models means that a large number of new molds need to be developed accordingly. Each new model has different body structures, component dimensions, and other characteristics, requiring corresponding molds to be custom-made. Mold development involves not only design costs but also a series of expenses including material procurement, processing and manufacturing, testing and debugging, which keeps mold investment costs high. For automakers, the huge mold development costs have become a heavy economic burden, hindering the company's development to some extent.

[0003] To alleviate this pressure, many automakers are considering platform-based design for the sunroof structure. The core idea of ​​platform-based design is to allow multiple car bodies to share the same basic structure and molds, thereby significantly reducing new model development costs. However, platform-based design faces a key technical challenge: how to meet the simultaneous production requirements of the edge flanging of the outer roof panel and the negative angle flanging of the inner sunroof within a single mold, while reducing the total number of mold processes. Furthermore, traditional sequential production methods not only involve large mold investments but also suffer from cumulative errors due to multiple positioning steps, severely impacting the appearance quality of the A-side of the outer roof panel and the sealing accuracy of the sunroof area. For example, a sunroof side shaping mold disclosed in patent CN104384329A cannot complete the negative angle flanging in one step. Platform-based design faces a crucial technical challenge: how to meet the design requirement of changing the inner sunroof flanging from a positive angle to a negative angle within a single mold, and complete production while reducing the total number of mold processes. Solving this problem is of paramount importance for promoting the platform-based development of automotive sunroof structures and achieving cost control, and is therefore particularly urgent. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a composite mold for negative angle flanging of the sunroof outer panel of an automobile roof and its forming method, which can realize flanging and shaping of the negative angle flanging area, and the product quality is stable and reliable.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A composite mold for flanging the negative corner of a car roof sunroof includes an upper mold body and a lower mold body, as well as an upper mold guide plate, a sliding positioning structure, and an outer flanging insert and an inner flanging insert for shaping the negative corner of the sunroof. The inner flanging insert is fixed on the sliding positioning structure, the outer flanging insert is slidably disposed within the sliding positioning structure, the sliding positioning structure is slidably disposed on the lower mold body, and the upper mold guide plate is disposed at the lower part of the upper mold body. The upper mold guide plate is a bidirectional guide plate structure that can simultaneously drive the sliding positioning structure and the outer flanging insert.

[0006] Further or preferred: The lower mold body is provided with a groove, the bottom of the sliding positioning structure is located in the groove through a bottom slider, and the end of the sliding positioning structure is provided with an elastic block.

[0007] The sliding positioning structure is a hollow frame structure, with the inner flanged inlay located on the inner end of the frame structure and the outer flanged inlay located within the hollow area of ​​the frame structure.

[0008] The lower part of the upper mold guide plate is a wedge structure with a larger upper part and a smaller lower part. The inner and outer sides of the wedge structure are provided with inclined guide plates. The inner inclined guide plate cooperates with the outer flange insert, and the outer inclined guide plate cooperates with the end guide plate located at the outer end of the frame structure.

[0009] The frame structure has a step on the side wall of the groove, and an outward-turned edge block guide plate is provided on the step. The outward-turned edge block is located on the outward-turned edge block guide plate.

[0010] The upper mold body is provided with a pressing core corresponding to the top of the outer flange insert, and the pressing core is provided with a contour pressing structure corresponding to the edge flange of the outer plate of the top cover.

[0011] The end guide plate is fixed to the inner wall of the outer end of the frame structure.

[0012] The inner end wall of the frame structure is provided with an elastic drive structure corresponding to the outward-flaring inlay.

[0013] The elastic drive structure is a set of springs arranged side by side. The inner end of the frame structure is provided with a mounting hole, and the outer wall of the inner end of the frame structure is provided with a cover plate. One end of the spring is installed in the mounting hole and positioned by the cover plate, and the other end of the spring is located in the groove provided on the inner side of the outer flange insert. The inner flange insert is fixed to the upper part of the inner end of the frame structure.

[0014] A forming method for shaping the negative corner of the sunroof on the outer panel of an automobile roof using the aforementioned composite mold for sunroof negative corner flanging includes the following steps: The upper mold body moves downward, and the bidirectional driven lower mold guide plate moves downward accordingly. When the lower mold guide plate applies downward pressure, it generates a shearing lateral force. After the inner side of the lower mold guide plate contacts the outer flange insert, it pushes the outer flange insert to generate a movement trajectory in the Y direction; at the same time, after the outer side of the upper mold guide plate contacts the sliding positioning structure, the sliding positioning structure and the inner flange insert on its inner end will generate a movement trajectory opposite to that of the outer flange insert in the Y direction, so that the inner flange insert and the outer flange insert cooperate to achieve the negative angle flange shaping of the top cover outer panel sunroof. When the outward-flared insert moves in the Y direction under the action of the oblique cutting lateral force, it will compress the spring located between the inner end of the sliding positioning structure and the outward-flared insert. The spring stores elastic potential energy. After the shaping is completed, the spring releases the elastic potential energy, providing driving force for the return reset of the outward-flared insert and the sliding positioning structure, ensuring that the mechanism can return to the initial state and prepare for the next shaping operation.

[0015] Compared with the prior art, the present invention has the following advantages: The composite mold and forming method for the negative angle flange of the sunroof outer panel of the car roof are reasonably designed. The upper mold guide plate is a two-way guide plate structure, which can simultaneously drive the sliding positioning structure and the outer flange insert. The sliding positioning structure drives the inner flange insert to move. Its special structural design can generate a diagonal lateral force when pressure is applied downward. After this lateral force contacts the outer flange insert, it pushes the outer flange insert to generate a movement trajectory in the Y direction. At the same time, the two-way upper mold guide plate and the sliding positioning structure constrain the inner flange insert to contact, generating a movement trajectory opposite to that of the outer flange insert in the Y direction. This allows the inner flange insert and the outer flange insert to cooperate with each other to perform shaping operations on the negative angle flange area of ​​the sunroof. It can effectively reduce the number of molds, improve production efficiency, reduce production costs, and at the same time ensure product quality stability, providing strong technical support for the efficient and platform-based production of the automotive manufacturing industry. Attached Figure Description

[0016] The following is a brief explanation of the contents of each of the accompanying drawings and the markings in the drawings: Figure 1 This is a schematic diagram of the outer structure of the top cover of the present invention.

[0017] Figure 2 For the present invention along Figure 1 Schematic diagram of section AA.

[0018] Figure 3 This is a schematic diagram of the top cover outer plate and composite mold of the present invention.

[0019] Figure 4 and Figure 5 This is a schematic diagram of the composite mold structure of the present invention.

[0020] Figure 6 This is a schematic diagram of the cross-section of the composite mold of the present invention.

[0021] Figure 7This is a schematic diagram of the overall mold structure of the present invention.

[0022] Figure 8 This is an enlarged schematic diagram of the mold for the flange shaping part of the present invention.

[0023] In the picture: 1. Sunroof negative angle flange, 2. Sliding positioning structure, 3. Upper mold guide plate, 4. Inner flange insert, 5. Outer flange insert, 6. Drive structure, 7. Bottom guide plate, 8. Upper guide plate, 9. Elastic block, 10. Cover plate, 11. Lower mold body, 12. Pressing core. Detailed Implementation

[0024] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and through the description of the examples.

[0025] Although the invention has been shown and described herein with reference to specific embodiments, it is not intended to be limited to the details shown. Rather, various modifications in detail may be made within the equivalent scope and scope of the claims without departing from the invention. In the drawings, the same item numbers refer to the same elements.

[0026] Throughout this disclosure, various terms are used to describe the physical shape or arrangement of features. Many of these terms are used to describe features conforming to a cylindrical or generally cylindrical geometry with the feature as its radius and a central axis perpendicular to that radius. Unless otherwise specified, the terms are given the following meanings: The terms “longitudinal,” “longitudinal,” “axial,” and “axial” refer to a direction, dimension, or orientation parallel to the central axis. The terms “radial” and “radially” refer to a direction, dimension, or orientation perpendicular to the central axis. The terms “inward” and “inner” refer to a direction, dimension, or orientation extending radially toward the central axis. The terms “outward” and “outer” refer to a direction, dimension, or orientation extending radially away from the central axis.

[0027] In this specification, relative terms such as “horizontal,” “vertical,” “upward,” “downward,” “top,” and “bottom,” and their derivatives (e.g., “horizontal,” “downward,” “upward,” etc.) should be interpreted as referring to the direction described or the direction shown in the accompanying drawings. These relative terms are for ease of description and are not generally intended to require a specific direction.

[0028] like Figures 1 to 8As shown, the composite mold for the negative corner flanging of the sunroof outer panel of an automobile roof includes an upper mold body, a lower mold body 11, an upper mold guide plate 3, a sliding positioning structure 2, and an outer flanging insert 5 and an inner flanging insert 4 for shaping the negative corner flanging of the sunroof. The outer flanging insert and the inner flanging insert are arranged opposite each other, and the sunroof edge is shaped by the movement of the outer flanging insert and the inner flanging insert towards each other, thereby realizing the flanging and shaping of the negative corner flanging area. The flanging composite mold is integrated to form a composite mold module. The module structure is easy to arrange and install, and can effectively improve production efficiency, reduce production costs, and ensure product quality stability, providing strong technical support for the efficient production of the automobile manufacturing industry.

[0029] The inner flange insert 4 is fixed on the sliding positioning structure 2, and the outer flange insert 5 is slidably disposed within the sliding positioning structure. The sliding positioning structure is slidably disposed on the lower mold body, and the upper mold guide plate 3 is disposed at the lower part of the upper mold body. The upper mold guide plate is a bidirectional guide plate structure that can simultaneously drive the sliding positioning structure and the outer flange insert. The bidirectional guide structure includes an outer guide plate and an inner guide plate arranged opposite to each other. The inner guide plate and the outer flange insert are fitted together, and the outer guide plate is fitted together with the inner side of the outer end of the sliding positioning structure. As the upper mold body moves downward, the upper mold guide plate can simultaneously drive the outer flange insert and the sliding positioning structure to move. The inner flange insert and the outer flange insert on the inner end of the sliding positioning structure are clamped synchronously to perform shaping treatment on the negative angle flange of the sunroof.

[0030] The upper mold guide plate of this invention is a bidirectional guide plate structure, which can simultaneously drive the sliding positioning structure and the outer flange insert. The sliding positioning structure drives the inner flange insert to move. That is, its special structural design can generate a lateral shearing force when pressure is applied downward. After this lateral force contacts the outer flange insert, it pushes the outer flange insert to generate a movement trajectory in the Y direction. At the same time, the bidirectional upper mold guide plate and the sliding positioning structure constrain the inner flange insert to contact, which will generate a movement trajectory opposite to that of the outer flange insert in the Y direction. This allows the inner flange insert and the outer flange insert to cooperate with each other to perform shaping operations on the negative angle flange area of ​​the sunroof. It can effectively reduce the number of molds, improve production efficiency, reduce production costs, and at the same time ensure product quality stability.

[0031] The lower mold body 11 has a groove, and the bottom of the sliding positioning structure is located in the groove via a bottom slider. The end of the sliding positioning structure is provided with an elastic block 9. That is, the sliding positioning structure is a movable sliding base. The sliding base is a rectangular base as a whole, and the groove of the lower mold body is also a rectangular groove. The sliding base is slidably located in the groove, resulting in a compact structure. Furthermore, the outer end of the sliding base is provided with two elastic blocks arranged side by side, or the inner wall of the groove of the lower mold body is provided with two elastic blocks arranged side by side corresponding to the outer end of the sliding base. The elastic blocks can be polyurethane elastic columns, which are fixedly installed by fasteners. This can limit the extreme position of the sliding base sliding outward and provide buffering to avoid abnormal noise.

[0032] Preferably, two parallel elastic columns are installed on the outer end of the sliding base; a circular groove is provided on the end face of the outer end of the sliding base, and a threaded hole is provided in the center of the circular groove. The center of the elastic column is fixedly installed by a mounting bolt through the threaded hole; furthermore, an opening groove is provided on the inner wall of the outer end of the lower mold body groove. The width of the opening groove is slightly larger than the outer diameter of the elastic column. Through the buffering of the elastic column, the end face of the sliding base fits against the inner wall of the outer end of the groove to achieve accurate positioning of the sliding base.

[0033] When the sliding base slides outward, the outer end of the elastic column enters the opening groove first. The deformation of the elastic column provides buffering, and the inner wall of the outer end of the groove limits the end face of the sliding base, avoiding abnormal noise and protecting the mold structure. The limiting is also accurate.

[0034] Preferably, the sliding positioning structure 2 is a hollow frame structure, that is, the frame structure is a hollow rectangular structure. The inner flanged inlay is fixed on the inner end of the frame structure. The inner flanged inlay and the sliding positioning structure move together. The outer flanged inlay is located in the hollow area of ​​the frame structure. The outer flanged inlay can slide in the hollow area. The negative angle flange is shaped by the combined movement of the inner flanged inlay and the outer flanged inlay.

[0035] The lower part of the upper mold guide plate 3 is a wedge structure that is larger at the top and smaller at the bottom. The upper part of the upper mold guide plate is a mounting plate. The wedge structure and the mounting plate are an integral structure, that is, the upper mold guide plate is an integral structural component, which is stable and reliable. The width of the mounting plate is greater than the width of the wedge structure, that is, the edge of the mounting plate protrudes. A set of mounting holes are provided on the protruding part. The upper mold guide plate is fixed to the upper mold body by fasteners passing through the mounting holes, and can move up and down with the upper mold body.

[0036] The wedge structure has inclined guide plates on both its inner and outer sides. These guide plates are fixed to the corresponding inclined surfaces of the wedge structure via countersunk holes and fasteners, and can be replaced. The inner inclined guide plate mates with the inclined guide plate of the outer flange insert, which is located on the outer flange insert. The outer inclined guide plate mates with the end guide plate located at the outer end of the frame structure. The upper mold guide plate has a bidirectional guide plate structure, which can simultaneously drive the outer flange insert and the sliding base when moving downwards.

[0037] Furthermore, the end guide plate is fixed to the inner wall of the outer end of the frame structure, and the end guide plate is also an inclined guide plate that cooperates with the outer inclined guide plate; the inner end wall of the frame structure is provided with an elastic drive structure corresponding to the outer flange insert; under the action of the bidirectional guide plate, the outer flange insert moves inward and the frame structure of the sliding base moves outward. At this time, the elastic drive structure is squeezed and stores elastic potential energy, and the negative angle flange shaping is stable and reliable; after the shaping is completed, the outer flange insert and the sliding base are synchronously reset through the elastic drive structure, and the operation is efficient.

[0038] The frame structure has steps on the side wall of the groove, and an outward-flared insert guide plate is provided on the steps, that is, an upper guide plate 8 is fixed on the steps; the outward-flared insert is set on the outward-flared insert guide plate, the structure is compact, and the outward-flared insert slides stably and reliably; the integrated setting forms an overall modular structure, which is conducive to installation and operation; or, a bottom guide plate 7 is provided at the bottom of the groove of the frame structure corresponding to the bottom of the outward-flared insert, the core structure is still that the outward-flared insert is within the frame structure, forming an overall mold structure.

[0039] A pressure core 12 is provided on the top of the outer flange insert on the upper mold body. The pressure core is provided with a contour pressing structure on the edge flange of the top cover outer plate. The contour pressing structure acts on the edge flange, and the forming is stable and reliable. Preferably, a vertical groove is provided at the bottom of the upper mold body. The pressure core is located in the vertical groove. A nitrogen spring is provided at the top of the pressure core. A vertical guide plate is provided between the side of the pressure core and the groove wall of the vertical groove. When the pressure core presses the material, it can move up and down in the vertical groove of the upper mold body, and the pressing is stable and reliable.

[0040] Preferably, the elastic drive structure 6 is a group of springs arranged side by side, the inner end of the frame structure is provided with mounting holes, and the outer wall of the inner end of the frame structure is provided with a cover plate 10. The end of the cover plate is fixed to the outer wall of the inner end of the frame structure by fasteners, which facilitates installation and makes the structure stable and reliable. One end of the spring is installed in the mounting hole and positioned by the cover plate, while the other end of the spring is located in the groove inside the outer flange insert. The inner flange insert is fixed to the upper part of the inner end of the frame structure. The integrated design is compact and occupies little space.

[0041] Furthermore, the upper part of the inner end of the frame structure is a mounting step, and the lower part of the inner flange insert is a step structure that matches the mounting step, ensuring a stable and reliable fit. The inner flange insert has a set of fixing holes in the vertical direction, and the mounting step has a set of mounting holes corresponding to the fixing holes, which are then fixed by bolts.

[0042] Both the inner and outer flanged inserts have matching shaping steps on their mating surfaces. A step is formed on the negative angle flange 1 of the sunroof on the outer panel of the car roof, which improves the strength of the upper structure of the part and reduces the risk of springback during side shaping.

[0043] This invention discloses a forming method for shaping the negative corner of the sunroof outer panel using a composite mold for flanging the sunroof outer panel of an automobile roof, comprising the following steps: The upper mold body moves downward, and the bidirectional driven lower mold guide plate moves downward accordingly. When the lower mold guide plate applies downward pressure, it generates a shearing lateral force. After the inner side of the lower mold guide plate contacts the outer flange insert, it pushes the outer flange insert to generate a movement trajectory in the Y direction; at the same time, after the outer side of the upper mold guide plate contacts the sliding positioning structure, the sliding positioning structure and the inner flange insert on its inner end will generate a movement trajectory opposite to that of the outer flange insert in the Y direction, so that the inner flange insert and the outer flange insert cooperate to achieve the negative angle flange shaping of the top cover outer panel sunroof. When the outward-flared insert moves in the Y direction under the action of the oblique cutting lateral force, it will compress the spring located between the inner end of the sliding positioning structure and the outward-flared insert. The spring stores elastic potential energy. After the shaping is completed, the spring releases the elastic potential energy, providing driving force for the return reset of the outward-flared insert and the sliding positioning structure, ensuring that the mechanism can return to the initial state and prepare for the next shaping operation.

[0044] The core objective of this invention is to provide a composite mold for flanging the negative angle of a sunroof on an automotive roof panel and its forming method. By optimizing the mold structure and production process, the development cost is reduced. This method not only meets the production requirements for flanging the negative angle of automotive sunroofs but also improves production efficiency and product quality stability, providing strong support for the sustainable development of the automotive manufacturing industry.

[0045] This composite mold mainly consists of an upper mold body, a lower mold body, an upper mold guide plate (bidirectional), an inner flange insert, an outer flange insert, a driver (spring), and a sliding base located on the lower mold. The key function of the sliding base is to constrain the stroke of the inner and outer flange inserts, ensuring that they move along a preset trajectory during operation and preventing product quality issues caused by stroke deviations.

[0046] The lower mold body is equipped with a drive structure connected to the movable baffle. The function of this drive structure is to provide the driving force required for the extension and retraction of the movable baffle, so as to ensure that the movable baffle can accurately and timely complete the blocking and avoidance actions, thereby improving the automation and accuracy of the production process. This part is an existing structure and will not be described in detail in this patent.

[0047] In this invention, the sliding base employs a spring laterally positioned within the base as the elastic driving structure. The choice of a spring as the driving structure is primarily based on the following advantages: Firstly, it has a simple structure and is easy to manufacture. Springs are common mechanical parts with mature production processes and low manufacturing difficulty, which can reduce the overall manufacturing cost of the mold. At the same time, the simple structure also makes the mold easier to assemble and maintain, reducing the workload and cost of later maintenance. Secondly, it reduces mold processes. The spring-driven structure can work in conjunction with other structures of the mold to achieve integrated motion control, avoiding the use of additional complex drive devices, thereby reducing mold processes, shortening the production cycle, and improving production efficiency. Thirdly, it meets the special design requirements of parts. For the production of special structures such as the negative angle flange of the sunroof outer panel of an automobile roof, the spring-driven structure can provide stable and controllable driving force to ensure the accuracy of the flange and shaping process and meet the design precision and quality requirements of the part. Through special structural design, it can simultaneously provide driving force for the return reset of the outer flange insert and the sliding positioning structure, with stable, reliable, and efficient operation.

[0048] Before designing the negative angle flange forming structure for the sunroof outer panel of an automobile, a comprehensive analysis of the component's structural characteristics, material properties, and manufacturing process requirements is necessary. As a crucial component of the automobile body, the appearance quality and structural strength of the outer panel are paramount. The structural design at the sunroof directly impacts the vehicle's sealing performance, aesthetics, and compatibility with other sunroof components.

[0049] The roof cover's outer panel has a convex arc shape. This arc structure presents complex material flow and deformation during the stamping process. According to material forming principles, during side forming, the anisotropy of the material—meaning differences in mechanical properties across different directions—can easily cause deformation on the A-side of the roof cover (i.e., the car's exterior surface). This deformation severely impacts the car's appearance quality and requires effective measures to avoid it. Furthermore, the welded surfaces after side forming are prone to wrinkling, material overlap, and springback. Wrinkling and overlap reduce weld quality, affecting connection strength and sealing; springback causes the part shape to deviate from design requirements, increasing subsequent assembly difficulty. Therefore, these issues must be fully considered during the design process, and corresponding solutions must be developed.

[0050] Figure 1 and Figure 2 As shown, in order to reduce the risk of surface A deformation caused by side forming, improve the strength of the upper structure of the part, and reduce the risk of springback during side forming, this invention adds a stepped structure to the overlapping area of ​​the skylight flange on the outer panel of the top cover. Through extensive experiments and data analysis, it was determined that the depth HI of the step should be controlled at 2-3 mm, the width WI at 9-12 mm, and the depth H of the step should remain consistent.

[0051] The determination of this size range is based on consideration of multiple factors. From the perspective of material deformation, appropriate step depth and width can guide the material to flow uniformly during the molding process, reduce stress concentration, and thus reduce the possibility of deformation on surface A. At the same time, uniform step depth can ensure the consistency of the part structure, improve overall strength, and effectively suppress springback. From the perspective of manufacturing process, this size range facilitates mold processing and manufacturing, and can ensure the molding accuracy of the stepped structure.

[0052] The forming quality of the vertical flange at the sunroof on the outer panel of the roof directly affects the appearance matching and sealing requirements between the sunroof reinforcement plate and the roof. Since this vertical flange requires Y-axis inward shaping, traditional mold structures struggle to achieve this, often necessitating additional processes, which not only increases production costs but also reduces production efficiency. To meet the matching requirements, this invention designs a specialized sunroof side shaping structure.

[0053] The shaping mechanism of this invention consists of an upper mold guide plate (bidirectional), an outer flange insert, a sliding base constraining an inner flange insert, an inner flange insert, and a drive structure (spring), forming a top cover side shaping mechanism. The coordinated work between these components is key to achieving precise shaping.

[0054] The upper mold guide plate (bidirectional) plays a guiding and force-transmitting role in the mechanism. Its special structural design generates a shearing lateral force when downward pressure is applied. This lateral force contacts the outer flange insert, pushing it to move in the Y direction. Simultaneously, the upper mold guide plate (bidirectional) contacts the inner flange insert, constraining it, and generates a movement trajectory opposite to that of the outer flange insert in the Y direction. This allows the inner and outer flange inserts to cooperate in shaping the part until the design requirements are met.

[0055] The drive mechanism (spring) plays a crucial dynamic role in the system. When the outer flange insert moves in the Y direction under the action of the oblique lateral force, it compresses the driver (spring), which stores elastic potential energy. After the shaping is completed, the spring releases the elastic potential energy, providing the driving force for the outer flange insert to return to its original position, ensuring that the system can return to its initial state and prepare for the next shaping operation.

[0056] A safety limit screw is provided above the upper mold guide plate (bidirectional), which limits the downward distance of the upper mold guide plate and prevents excessive downward pressure from the upper mold guide plate and damage to other components of the mechanism. One end of the outward flange insert is equipped with a drive structure (spring), which, in addition to providing return reset force, also works with other limit components to ensure that the outward flange insert can accurately reset during the return process.

[0057] When the upper mold guide plate (bidirectional) is not in contact with the outer flange insert and the sliding base constraining the inner flange insert, the return spring of the drive structure (spring), together with the limiting top block and the sliding block return limiting block at the other end of the wedge slider, work together to ultimately achieve the reset of the entire mechanism. The precise reset of the mechanism not only facilitates the handling of parts but also ensures the consistency and stability of the next production run.

[0058] Furthermore, this invention arranges the top cover edge flanging module and the sunroof negative angle flanging module in the same mold, forming a composite integral mold structure. The layout is as follows: the top cover edge flanging module is arranged around the outside of the mold, and the sunroof negative angle flanging module is arranged in the middle of the mold. Both share a set of upper and lower mold bases and a guiding system. The workflow is as follows: Initial state: The upper mold is located at the upper stop point, and the sheet metal is placed on the lower mold positioning block; During the pressing stage: the upper die moves downward, the pressing plate contacts the sheet material, and the nitrogen spring applies a clamping force; Edge flanging stage: The upper mold continues to descend, and the edge flanging insert cooperates with the lower mold to complete the edge flanging; Sunroof negative angle flanging stage: The upper mold guide plate drives the sunroof negative angle flanging mechanism, and the inner and outer flanging inserts move towards each other to complete the negative angle flanging; Simultaneous completion: The edge flanging and the sunroof negative corner flanging are completed in the same stroke; Reset and unloading: The upper mold moves upward, the spring drives the flange insert to reset, and the unloading device ejects the workpiece.

[0059] The machining accuracy of this flanging and shaping die directly affects the molding quality of the product. Therefore, it is necessary to strictly control various dimensional tolerances and geometric tolerances during the machining process. For key components such as the upper die guide plate (two-way), inner flanging insert, and outer flanging insert, high-precision machining equipment, such as CNC milling machines and grinding machines, is used to ensure that their surface roughness and dimensional accuracy meet the design requirements.

[0060] In terms of material selection, considering that the mold needs to withstand large impact and friction during operation, high-strength and high-wear-resistant alloy materials such as Cr12MoV are selected for key components, and appropriate heat treatment processes are carried out to improve the hardness and toughness of the materials and extend the service life of the mold.

[0061] The mold assembly process is equally crucial. Before assembly, all parts must be cleaned and inspected to ensure they are free of burrs and damage. During assembly, a reasonable assembly sequence and method should be adopted according to the assembly drawings to ensure uniform clearance and flexible movement between components. For critical components such as positioning devices and actuators, precise adjustments are required to ensure stable and reliable performance.

[0062] After assembly, the mold undergoes trial molding and debugging. Trial molding checks the product's forming quality, such as the flange angle and surface quality; any problems are addressed promptly. During debugging, the focus is on the coordination of the mechanism's movements, the accuracy of its reset, and the reliability of the safety limit devices, until the mold can stably produce qualified products.

[0063] When using this mold for production, a comprehensive production process specification is required to ensure the standardization and normalization of the production process. First, raw materials must be rigorously inspected to ensure their chemical composition and mechanical properties meet requirements. The cutting dimensions of the raw materials must be accurate to avoid forming defects due to dimensional deviations. During the stamping process, process parameters such as stamping speed and pressure must be carefully controlled. Excessive stamping speed may lead to uneven material deformation and defects such as cracks; insufficient pressure may result in incomplete part forming and inadequate dimensional accuracy. Optimal process parameters should be determined through multiple trials and monitored and adjusted in real time during production.

[0064] Regular maintenance and upkeep of the molds are crucial for ensuring their long-term stable operation. After production, promptly clean the mold surface of waste materials and oil stains, inspect the wear of each component, and replace or repair severely worn parts in a timely manner. Simultaneously, regularly inspect vulnerable parts such as actuators (springs) to ensure their elasticity is in good condition.

[0065] Compared with traditional mold structures, the negative angle flanging forming structure for the sunroof outer panel of the automobile roof designed in this invention has significant cost advantages. First, this mold can complete the conversion from a positive angle to a negative angle of the sunroof inner flanging in a single mold, reducing the number of molds and thus lowering the mold development and manufacturing costs.

[0066] Secondly, the mold has a simple structure, is easy to manufacture and assemble, reducing processing and assembly time and lowering labor costs. At the same time, mold maintenance and upkeep are relatively simple, reducing subsequent maintenance costs. In terms of production efficiency, because the mold reduces mold-making processes and shortens the production cycle, it increases production output per unit time. Product quality stability is guaranteed, reducing scrap rates and further lowering production costs.

[0067] Furthermore, this mold structure meets the platform design requirements of the sunroof structure on the vehicle body, allowing multiple vehicle bodies to share a single mold, significantly reducing the development cost of new models. This is of great significance for automakers to improve their market competitiveness. With the continuous development of the automotive industry, platform-based and modular design has become a development trend in the automotive manufacturing industry. The negative angle flanging forming structure for the outer panel sunroof of the vehicle body and its design method provided by this invention conform to this development trend and have broad application prospects.

[0068] This technology is not only applicable to the molding of the sunroof area of ​​the outer panel of the car roof, but its design concept and technical ideas can also be applied to the negative angle flanging molding of other outer covering parts of the car, such as car doors and trunk lids, providing a reference for technological innovation in the automotive manufacturing industry.

[0069] By promoting and applying this technology, automakers can effectively reduce mold development and manufacturing costs, improve production efficiency and product quality, and enhance their core competitiveness in the market. At the same time, the application of this technology also helps promote the sustainable development of the automotive manufacturing industry, reduce resource waste, and improve economic and social benefits.

[0070] The above description is merely an illustration of preferred embodiments of the present invention, and the above technical features can be arbitrarily combined to form multiple embodiments of the present invention.

[0071] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the concept and technical solution of the present invention, or the direct application of the concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A compound die for negative angle flanging of an automobile roof panel sunroof, comprising an upper die body and a lower die body, characterized in that: It also includes an upper mold guide plate, a sliding positioning structure, and an outer flange insert and an inner flange insert for shaping the negative angle flange of the sunroof; the inner flange insert is fixed on the sliding positioning structure, the outer flange insert is slidably disposed in the sliding positioning structure, the sliding positioning structure is slidably disposed on the lower mold body, the upper mold guide plate is disposed at the lower part of the upper mold body, and the upper mold guide plate is a bidirectional guide plate structure that can simultaneously drive the sliding positioning structure and the outer flange insert.

2. The composite mold for the negative angle flange of the sunroof outer panel of an automobile roof as described in claim 1, characterized in that: The lower mold body is provided with a groove, the bottom of the sliding positioning structure is located in the groove through a bottom slider, and the end of the sliding positioning structure is provided with an elastic block.

3. The composite mold for the negative angle flange of the sunroof outer panel of the automobile roof as described in claim 1, characterized in that: The sliding positioning structure is a hollow frame structure, with the inner flanged inlay located on the inner end of the frame structure and the outer flanged inlay located within the hollow area of ​​the frame structure.

4. The composite mold for the negative angle flange of the sunroof outer panel of the automobile roof as described in claim 3, characterized in that: The lower part of the upper mold guide plate is a wedge structure with a larger upper part and a smaller lower part. The inner and outer sides of the wedge structure are provided with inclined guide plates. The inner inclined guide plate cooperates with the outer flange insert, and the outer inclined guide plate cooperates with the end guide plate located at the outer end of the frame structure.

5. The composite mold for the negative angle flange of the sunroof outer panel of an automobile roof as described in claim 3, characterized in that: The frame structure has a step on the side wall of the groove, and an outward-turned edge block guide plate is provided on the step. The outward-turned edge block is located on the outward-turned edge block guide plate.

6. The composite mold for the negative angle flange of the sunroof outer panel of an automobile roof as described in claim 3, characterized in that: The upper mold body is provided with a pressing core corresponding to the top of the outer flange insert, and the pressing core is provided with a contour pressing structure corresponding to the edge flange of the outer plate of the top cover.

7. The composite mold for the negative angle flange of the sunroof outer panel of an automobile roof as described in claim 4, characterized in that: The end guide plate is fixed to the inner wall of the outer end of the frame structure.

8. The composite mold for the negative angle flange of the sunroof outer panel of an automobile roof as described in claim 4, characterized in that: The inner end wall of the frame structure is provided with an elastic drive structure corresponding to the outward-flaring inlay.

9. The composite mold for the negative angle flange of the sunroof outer panel of an automobile roof as described in claim 8, characterized in that: The elastic drive structure is a set of springs arranged side by side. The inner end of the frame structure is provided with a mounting hole, and the outer wall of the inner end of the frame structure is provided with a cover plate. One end of the spring is installed in the mounting hole and positioned by the cover plate, and the other end of the spring is located in the groove provided on the inner side of the outer flange insert. The inner flange insert is fixed to the upper part of the inner end of the frame structure.

10. A forming method for shaping the negative corner of the sunroof outer panel of an automobile roof using the composite mold for flanging the sunroof negative corner as described in any one of claims 1 to 9, characterized in that: The molding method includes the following steps: The upper mold body moves downward, and the bidirectional driven lower mold guide plate moves downward accordingly. When the lower mold guide plate applies downward pressure, it generates a shearing lateral force. After the inner side of the lower mold guide plate contacts the outer flange insert, it pushes the outer flange insert to generate a movement trajectory in the Y direction; at the same time, after the outer side of the upper mold guide plate contacts the sliding positioning structure, the sliding positioning structure and the inner flange insert on its inner end will generate a movement trajectory opposite to that of the outer flange insert in the Y direction, so that the inner flange insert and the outer flange insert cooperate to achieve the negative angle flange shaping of the top cover outer panel sunroof. When the outward-flared insert moves in the Y direction under the action of the oblique cutting lateral force, it will compress the spring located between the inner end of the sliding positioning structure and the outward-flared insert. The spring stores elastic potential energy. After the shaping is completed, the spring releases the elastic potential energy, providing driving force for the return reset of the outward-flared insert and the sliding positioning structure, ensuring that the mechanism can return to the initial state and prepare for the next shaping operation.

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