A process for controlling the rounded corners of the appearance contour of automobile cover parts

Abstract

The present application relates to a process method for controlling the rounded corners of the appearance contour of an automobile cover, comprising the following steps: using the swept surface command in the three-dimensional design software, selecting a defined vector direction in the draft direction option, the vector direction is consistent with the actual flanging direction of the flanging die, and then defining the draft angle, the direction of the draft angle is consistent with the direction of the springback angle expected to be generated by the flanging along the actual flanging direction, and generating the required swept surface as the design folding surface of the fender outer panel; using the stretch surface command in the three-dimensional design software to achieve folding, selecting the appearance modeling contour line, the definition of the stretching direction is consistent with the vector square of the draft angle of the design folding surface of the appearance contour of the fender outer panel, and generating a stretch surface along the flanging direction as the process folding surface, and the process folding surface is a spatial single curved surface. The present application makes the physical size of the appearance contour rounded corners of the fender outer panel uniform and consistent, meets the product size requirements of the fender outer panel, and improves the perceived quality of the automobile appearance modeling.

Description

Technical Field

[0001] The present application relates to the technical field of passenger car bodies, and in particular to a process method for controlling the rounded corners of the appearance contour of an automobile covering part. Background Art

[0002] In order to facilitate processing and assembly, the appearance of the car is divided into multiple external stamping parts and non-metal parts, such as Figure 1 The hood outer panel 1, the fender outer panel 2, the door outer panel 3, the front bumper 4, the front headlight 5, etc. are then assembled into one body, wherein the product appearance contour on both sides of the appearance styling block is an important feature of the automobile styling, and the quality of the appearance contour directly affects the perceived quality of the automobile appearance styling.

[0003] like Figure 2 As shown, taking the division of the hood outer panel 1 and the fender outer panel 2 as an example, the appearance contours of the hood outer panel 1 and the fender outer panel 2 at the division point, the appearance contour of the hood outer panel 1 is an edge-wrapped structure, including a hood appearance contour fillet 6 and an edge-wrapped surface 9, and the appearance contour of the fender outer panel 2 is a folded edge structure, including a fender appearance contour fillet 7 and a designed folded edge surface 8. The edging structure of the appearance contour of the hood outer panel 1 can be achieved by robot hemming or mold pressing, so that the hood outer panel 1 is folded along the edge of the hood inner panel 10 to achieve the assembly of the inner and outer panels. Whether using robot hemming or mold pressing, both methods can ensure that the size of the hood appearance contour fillet 6 of the hood outer panel remains consistent.

[0004] The folding structure of the appearance contour of the fender outer panel 2 is realized by using a flanging process with a stamping die, and the function of the designed folding surface 8 is to enhance the rigidity of the product. The hood appearance contour fillet 6 and the fender appearance contour fillet 7 are part of the appearance styling features. In actual production and assembly, defects such as inconsistent size and uneven fillet of the fender appearance contour fillet 7 of the fender outer panel 2 often occur, resulting in uneven gaps in the appearance styling of the car in this area, uneven appearance contour fillet, and other appearance defects, affecting the perception and beauty of the car appearance styling.

[0005] The exterior shape of the car is a three-dimensional curved surface, so the contours of the exterior shape blocks are also located on the three-dimensional curved surface, such as the appearance contour of the fender outer panel 2. Figure 3 As shown, the appearance contour folding structure of the fender outer panel 2 is realized by the stamping flanging process. Taking the appearance contour folding structure of the fender outer panel 2 as an example, the traditional fender outer panel 2 stamping process design process is: ① product engineers complete the appearance contour folding structure design of the fender outer panel 2 according to certain functional requirements, ② stamping process engineers complete the stamping process design according to product characteristics, ③ mold engineers complete the mold structure design according to the stamping process plan, ④ mold processing, manufacturing and debugging, and produce qualified parts.

[0006] In the first step of the process, when product engineers carry out structural design, they usually cannot consider the specific details of the stamping process design and the physical quality, and only ensure that the stamping flanging process can be realized. The appearance contour folding structure of the fender outer panel 2 is designed using CAD design software. Taking CATIA software as an example, the specific steps are as follows: (1) Use the stretch surface command in the CATIA design software to realize the folding. Click the stretch surface command to select the appearance contour line 11, select the stretching direction, and input the parameters to determine the stretching range along a defined vector direction to generate a stretch surface. The surface is a spatial single curved surface that intersects with the automobile appearance contour line at the appearance contour line. (2) Use the edge fillet command to fillet the corners. Select the appearance contour line 11 to be filleted and generate the fender appearance contour fillet 7, thereby completing the design of the appearance contour folding structure features of the fender outer panel 2.

[0007] The second step in the process is the design of the stamping process scheme for the appearance contour folding structure features, which is completed by combining multiple processes, such as Figure 4 As shown in the figure, in the first process, the rounded corners 7 and the designed folding surface 8 of the fender appearance that need to be realized by the flanging process are unfolded to the product drawing supplementary surface and drawn. In the second process, the excess waste part is cut off by the trimming process. In the third process, the flanging process is used to realize the structural characteristics of the folding surface. When the mold is used for stamping, after the external load on the mold is unloaded, the product process parts are accompanied by elastic deformation, and the size of the product process parts is inconsistent with the mold size. This phenomenon is called stamping springback. Figure 6 The medium-rebound folding surface 12 is the state of the designed folding surface 8 after the folding rebounds.

[0008] Therefore, when designing the stamping and flanging process plan in the third process, the stamping engineer will design the flanging stamping springback angle compensation based on experience and CAE simulation to eliminate the unqualified dimensional defects of the process parts caused by stamping springback. The specific steps are that the stamping engineer confirms the specific value of the springback angle compensation based on experience and CAE simulation springback analysis, and then completes the 3D design of the compensation sheet in the CAD software. Taking CATIA software as an example, the rotation command is used to rotate the folded edge surface along the normal of the spatial appearance contour line 11. The rotation direction is opposite to the direction of the springback folded edge surface 12. The rotation value is the angle value that needs springback compensation, and the compensation folded edge surface 13 after springback compensation is obtained. Then, the edge fillet command is used to select the appearance contour line 11 to be rounded, and the fender appearance contour fillet 7 is generated, thereby completing the springback compensation process sheet design of the appearance contour folding structural characteristics of the fender outer panel 2. The compensated appearance contour section is as shown Figure 5 and Figure 6 shown.

[0009] When designing the stamping and flanging process of the appearance contour folding structure of the fender outer panel 2, the definition of the stamping and flanging direction must be consistent with the vector direction of the compensated compensating flanging surface 13 to ensure that the gap between the flanging die 15 and the flanging punch 16 is uniform, thereby achieving good flanging quality.

[0010] In the implementation process of the existing technology, it is impossible to define the stamping flanging direction 14 to be consistent with the vector direction of the compensated compensating folding surface 13. The reason is that in the product design of step ①, the original product's appearance contour design folding surface 8 is a three-dimensional single curved surface, and the stretching direction of the designed folding surface 8 is determined and unique. When designing the stamping process plan in step ②, the stamping process must take into account the stamping flanging rebound of the appearance contour design folding surface 8. In order to ensure that the angle between the compensated compensating folding surface 13 and the appearance contour design folding surface 8 of the original product at any normal section is a constant value, it is necessary to rotate the original product's designed folding surface 8 along the normal direction of the appearance modeling contour line 11. The resulting compensating folding surface 13 is a spatial hyperbolic surface, and the flanging direction of the spatial hyperbolic surface at any section is different, such as Figure 7 shown.

[0011] When the stamping die is working, Figure 8 As shown, the flanging die 15 can only move along a certain vector direction for flanging, and cannot achieve simultaneous movement in multiple vector directions. Therefore, when defining the stamping flanging direction 14, it is impossible to define it accurately, and only an approximate flanging angle can be found and defined as the stamping flanging direction 14 for flanging. In this way, when the stamping flanging die structure is designed and processed, the flanging gap 17 between the flanging die 15 and the flanging punch 16 cannot be uniform at any cross section, resulting in inconsistent extrusion of the steel plate material between the flanging die 15 and the flanging punch 16 during the flanging process, and uneven material flow, which ultimately affects the consistency and smoothness of the size of the fender contour radius 7, thereby affecting the appearance perception and aesthetics of the car, and requiring a large amount of manpower and material resources to debug the mold to eliminate defects, increasing the cost of the entire vehicle. Summary of the invention

[0012] The embodiment of the present application provides a process method for controlling the radius of the appearance contour of an automobile cover, so as to solve the problem in the related art that it is impossible to define the stamping flanging direction to be consistent with the vector direction of the compensated flanging surface after compensation, resulting in inconsistent extrusion degrees of the steel plate material between the flanging die and the flanging punch, uneven material flow, and ultimately affecting the consistency and smoothness of the appearance contour radius.

[0013] The present application provides a process for controlling the rounded corners of the appearance contour of an automobile cover, comprising the following steps:

[0014] Design of the hemming structural features of the outer fender panel appearance contour. Use the swept surface command in the 3D design software, select a defined vector direction in the draft direction option, the vector direction is consistent with the actual stamping flanging direction of the flanging die, and then define the draft angle. The direction of the draft angle is consistent with the springback angle expected to be generated by the flanging along the actual stamping flanging direction, and generate the required swept surface as the design hemming surface of the outer fender panel.

[0015] The process design of the fender outer panel appearance contour folding structure uses the stretch surface command in the 3D design software to achieve folding, selects the appearance modeling contour line, and defines the stretching direction to be consistent with the vector square of the draft angle of the designed folding surface of the fender outer panel appearance contour. A stretching surface is generated along the stamping flanging direction as the process folding surface, and the process folding surface is a spatial single curved surface.

[0016] In the embodiment of the present application, because the draft direction of the process folding surface is consistent with the design folding surface of the original appearance contour of the fender outer panel, and the draft direction of the design folding surface is consistent with the flange rebound angle direction of the process folding surface, the folding structure design of the appearance contour of the fender outer panel has actually taken into account the compensation of the flange rebound angle of the draft angle.

[0017] The process flanging surface is generated by the stretch surface command. It is a single curved surface in space with a unique drawing vector direction. The flanging direction is consistent with the drawing vector direction of the process flanging surface, avoiding the uneven design of the flanging gap between the flanging die and the flanging punch. The spacing of the flanging gap is the same as the thickness of the designed flanging surface.

[0018] After stamping and flanging, the stamping springback that is objectively generated will rebound at an angle of 3° to 5° along the normal direction of the appearance contour line, which is consistent with the position of the designed folding surface in the original appearance contour folding structure of the fender outer panel.

[0019] The flanging gap between the flanging die and the flanging punch is uniform, which also improves the flanging quality of the fender appearance contour radius and the designed folding surface of the fender outer panel, making the actual size of the fender appearance contour radius of the fender outer panel uniform and consistent, meeting the product size requirements of the fender outer panel, thereby improving the perceived quality of the automobile appearance styling.

[0020] In some embodiments, before selecting a defined vector direction in the draft direction option, the following steps are also included:

[0021] Select the straight contour type in the Contour Type option, select Use Draft Direction in the Subtype option, and select Appearance Modeling Contour in the Guide Curve 1 option.

[0022] In some embodiments, after generating the required swept surface as the designed hem surface of the fender outer panel, the following steps are further included:

[0023] The edge fillet command is used to complete the fillet operation of the fender appearance contour fillet, thereby completing the fender outer panel appearance contour folding structural feature design.

[0024] In some embodiments: the draft angle is 3° to 5°.

[0025] In some embodiments: the flanging mold includes a flanging die and a flanging punch, the stamping flanging direction of the flanging die is consistent with the vector direction, and a flanging gap of the flanging surface of the stamping process is provided between the flanging die and the flanging punch, and the spacing of the flanging gap is the same as the thickness of the designed flanging surface.

[0026] In some embodiments, the step of generating a stretching surface along the stamping flanging direction as a process flanging surface, wherein the process flanging surface is a spatial single curved surface, further comprises the following steps:

[0027] By using the edge fillet command, select the appearance contour line to be filleted and generate the fender appearance contour fillet, thus completing the fender outer panel appearance contour folding structure process design.

[0028] In some embodiments: the 3D design software is Catia or Pro-E.

[0029] In some embodiments: the fender outer panel is a front fender outer panel of an automobile.

[0030] In some embodiments: the exterior styling contour line intersects with the exterior styling surface of the automobile, and the exterior styling contour line is a splicing contour line of a fender outer panel and a hood outer panel and / or a splicing contour line of a fender outer panel and a door panel outer panel.

[0031] In some embodiments: the value of the angle between the designed folding edge surface and the vector direction defining the draft angle in any cross section is consistent with the defined draft angle.

[0032] The beneficial effects of the technical solution provided by this application include:

[0033] The embodiment of the present application provides a process method for controlling the fillet of the appearance contour of an automobile cover. The process method for controlling the fillet of the appearance contour of an automobile cover of the present application is to first design the structural features of the appearance contour folding of the fender outer panel, and use the swept surface command in the three-dimensional design software to select a defined vector direction in the draft direction option, the vector direction is consistent with the actual flanging direction of the flanging mold, and then define the draft angle, the direction of the draft angle is consistent with the direction of the springback angle expected to be generated by the flanging along the actual flanging direction, and generate the required swept surface as the design folding surface of the fender outer panel; the second step is to design the process of the fender outer panel appearance contour folding structure, and use the stretch surface command in the three-dimensional design software to achieve folding, select the appearance modeling contour line, the definition of the stretch direction is consistent with the vector square of the draft angle of the design folding surface of the appearance contour of the fender outer panel, and generate a stretch surface along the flanging direction as the process folding surface, and the process folding surface is a spatial single curved surface.

[0034] Therefore, the process method of controlling the fillet of the appearance contour of an automobile cover in the present application, under the premise of meeting the product quality requirements of the appearance contour of the fender outer panel, changes the product design method of the designed folded edge surface in the fender appearance contour folding structure, and uses the swept surface command to complete the surface design of the designed folded edge surface. During the design process, the effective and unique definition of the flanging direction in the stamping project, the uniformity and consistency of the flanging gap, and the consistency of the rebound angle and compensation angle of any cross-section of the appearance contour line are considered in advance and guaranteed, thereby improving the appearance contour fillet of the fender outer panel and the flanging quality of the designed folded edge surface, making the actual size of the appearance contour fillet of the fender outer panel uniform and consistent, meeting the product size requirements of the fender outer panel, and improving the perceived quality of the automobile appearance. This method can be extended to the part development of the appearance contour folding structure of covers at all similar styling blocks in automobile appearance. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 It is a schematic diagram of some blocks of automobile exterior styling in the prior art;

[0037] Figure 2 for Figure 1 A cross-sectional view along the aa direction;

[0038] Figure 3 A schematic diagram of the folding of the folded edge surface of the fender outer panel in the prior art;

[0039] Figure 4 It is a schematic diagram of the fender outer panel stamping process flow in the prior art;

[0040] Figure 5 It is a structural schematic diagram of a fender outer panel in the prior art;

[0041] Figure 6 for Figure 5 A cross-sectional view along the bb direction;

[0042] Figure 7 It is a schematic diagram of the structure of the design of the folding surface and the compensation folding surface in the prior art;

[0043] Figure 8 A schematic diagram of the hemming of the fender outer panel compensating hemming surface in the prior art;

[0044] Fig. 9 A schematic structural diagram of a fender outer panel of an embodiment of the present application;

[0045] Fig.10 for Fig. 9 A cross-sectional view along the cc direction;

[0046] Fig.11 A schematic diagram of the folding of the process folding surface of an embodiment of the present application;

[0047] Fig.12 This is a working interface diagram of the swept surface command in an embodiment of the present application.

[0048] Reference numerals:

[0049] 1. Hood outer panel; 2. Fender outer panel; 3. Door outer panel; 4. Front bumper; 5. Headlight; 6. Hood appearance contour fillet; 7. Fender appearance contour fillet; 8. Design folding surface; 9. Edge surface; 10. Hood inner panel; 11. Appearance shape contour line; 12. Rebound folding surface; 13. Compensation folding surface; 14. Stamping flanging direction; 15. Flanging die; 16. Flanging punch; 17. Flanging gap; 18. Process folding surface. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0051] The embodiment of the present application provides a process method for controlling the radius of the appearance contour of an automobile cover, which can solve the problem in the related art that it is impossible to define the stamping flanging direction to be consistent with the vector direction of the compensated flanging surface after compensation, resulting in inconsistent extrusion degrees of the steel plate material between the flanging die and the flanging punch, uneven material flow, and ultimately affecting the consistency and smoothness of the appearance contour radius.

[0052] See also Figures 9 to 12 As shown, the embodiment of the present application provides a process for controlling the rounded corners of the appearance contour of an automobile cover, comprising the following steps:

[0053] Step 1: Design of the fender outer panel appearance contour folding structure features. Product engineers complete the fender outer panel appearance contour folding structure feature design in CAD software according to the automotive function requirements. Taking CATIA software as an example, the specific steps are:

[0054] (1) Fig.12 As shown, activate the Sweep Surface command in CATIA software and the local working interface of the Sweep Surface command.

[0055] (2) In the swept surface work interface, in the contour type option, select the second contour type, that is, the straight line contour type.

[0056] (3) In the Subtype options, select the Use draft direction option.

[0057] (4) In the Guide Curve 1 option, select Appearance Modeling Contour Line 11.

[0058] (5) In the draft direction option, select a defined vector direction that is consistent with the actual flanging direction of the flanging die, and then define a draft angle of 3° to 5°. The direction of the draft angle is defined to be consistent with the direction of the springback angle expected to be generated by the flanging along the actual flanging direction.

[0059] (6) Click the OK button to generate the required swept surface as the designed folding surface 8 of the fender outer panel 2. The angle between the designed folding surface 8 and the vector direction of the defined draft angle in any cross section is consistent with the defined draft angle.

[0060] (7) Finally, use the edge fillet command to complete the fillet operation of the fender appearance contour fillet 7, thereby completing the design of the fender outer panel appearance contour folding structure feature.

[0061] Step 2: Fender outer panel appearance contour folding structure process design. After the product engineer completes the fender outer panel appearance contour folding structure feature design, the stamping process engineer begins to carry out the fender outer panel appearance contour folding structure process design. Taking CATIA software as an example, the specific steps are:

[0062] (1) The folding is realized by using the stretch surface command in the CATIA design software. The appearance contour line 11 is selected. The stretching direction is defined to be consistent with the vector square of the draft angle of the design folding surface 8 of the appearance contour of the fender outer panel 2. That is, a stretching surface is generated along the stamping flanging direction 14 as the process folding surface 18. The process folding surface 18 is a spatial single curved surface and intersects with the appearance styling surface of the automobile at the appearance contour line 11. The appearance contour line 11 is the splicing contour line of the fender outer panel 2 and the hood outer panel 1 and / or the splicing contour line of the fender outer panel 2 and the door panel outer panel 3.

[0063] (2) Then, the edge fillet command is used to select the appearance contour line 11 to be filleted, and the fender appearance contour fillet 7 is generated, thereby completing the fender outer panel appearance contour folding structure process design.

[0064] In the embodiment of the present application, because the process folding surface 18 is consistent with the draft direction of the designed folding surface 8 of the original appearance contour of the fender outer panel 2, the draft angle of the designed folding surface 8 is 3°~5°, and the draft direction is consistent with the flange rebound angle direction of the process folding surface 18, the appearance contour folding structure design of the fender outer panel 2 has actually taken into account the compensation of the flange rebound angle of 3°~5°.

[0065] The process flanging surface 18 is generated by the stretch surface command, which is a single curved surface in space with a unique drawing vector direction. The stamping flanging direction 14 is consistent with the drawing vector direction of the process flanging surface 18, avoiding the uneven design of the flanging gap 17 between the flanging die 15 and the flanging punch 16. The spacing of the flanging gap 17 is the same as the thickness of the designed flanging surface 8.

[0066] After the stamping and flanging, the stamping springback objectively generated will rebound at an angle of 3° to 5° along the normal direction of the appearance contour line 11 , which is consistent with the position of the designed folding surface 8 in the original appearance contour folding structure of the fender outer panel 2 .

[0067] The flanging gap 17 between the flanging die 15 and the flanging convex die 16 is uniform, which also improves the flanging quality of the fender appearance contour radius 7 and the designed folding surface 8 of the fender outer panel 2, making the actual size of the fender appearance contour radius 7 of the fender outer panel 2 uniform and consistent, meeting the product size requirements of the fender outer panel 2, thereby improving the perceived quality of the automobile appearance.

[0068] How it works

[0069] The embodiment of the present application provides a process method for controlling the rounded corners of the appearance contour of an automobile cover. Since the first step of the process method for controlling the rounded corners of the appearance contour of an automobile cover is to design the structural features of the appearance contour folding of the fender outer panel 2, the swept surface command in the three-dimensional design software is used to select a defined vector direction in the draft direction option, and the vector direction is consistent with the actual flanging direction of the flanging mold. Then, the draft angle is defined, and the direction of the draft angle is consistent with the direction of the springback angle expected to be generated by the flanging along the actual flanging direction, so as to generate the required swept surface as the designed folding surface 8 of the fender outer panel 2.

[0070] The second step is to carry out the process design of the folding structure of the appearance contour of the fender outer panel 2. The folding is realized by using the stretch surface command in the three-dimensional design software. The appearance modeling contour line 11 is selected. The definition of the stretching direction is consistent with the vector square of the draft angle of the design folding surface 8 of the appearance contour of the fender outer panel 2. A stretching surface is generated along the flanging direction as the process folding surface 18, and the process folding surface 18 is a spatial single curved surface.

[0071] Therefore, the process method of controlling the rounded corners of the appearance contour of an automobile cover in the present application, on the premise of meeting the product quality requirements of the appearance contour of the fender outer panel 2, changes the product design method of the designed folded edge surface in the folded edge structure of the appearance contour of the fender outer panel 2, and uses the swept surface command to complete the surface design of the designed folded edge surface 8. During the design process, the effective and unique definition of the flanging direction in the stamping project, the uniformity of the flanging gap 17, and the consistency of the rebound angle and compensation angle of any cross-section of the appearance contour line 11 are considered in advance and guaranteed. This improves the appearance contour rounded corners of the fender outer panel 2 and the flanging quality of the designed folded edge surface.

[0072] The actual size of the rounded corners of the appearance contour of the fender outer panel 2 is made uniform and consistent, which meets the product size requirements of the fender outer panel 2 and improves the perceived quality of the automobile's appearance. This method can be extended to the development of parts for the appearance contour folding structure of the cover parts at all similar styling blocks in the automobile's appearance.

[0073] In the description of the present application, it should be noted that the terms "upper", "lower", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0074] It should be noted that, in this application, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0075] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A process for controlling the rounded corners of the appearance contour of an automobile cover, characterized in that: The following steps are involved: Designing the hemming structural features of the outer fender panel (2) by using the swept surface command in the three-dimensional design software, selecting a defined vector direction in the draft direction option, wherein the vector direction is consistent with the actual flanging direction of the flanging die, and then defining a draft angle, wherein the direction of the draft angle is consistent with the direction of the springback angle expected to be generated by the flanging along the actual flanging direction, and generating the required swept surface as the designed hemming surface (8) of the outer fender panel (2); The outer fender panel (2) appearance contour folding structure process design is implemented by using the stretch surface command in the three-dimensional design software, the appearance modeling contour line (11) is selected, the stretching direction is defined to be consistent with the vector direction of the draft angle of the design folding surface (8) of the appearance contour of the outer fender panel (2), and a stretching surface is generated along the stamping flanging direction (14) as a process folding surface (18), and the process folding surface (18) is a spatial single curved surface; The flanging die comprises a flanging die (15) and a flanging punch (16); the stamping flanging direction (14) of the flanging die (15) is consistent with the vector direction; a flanging gap (17) of a stamping process flanging surface (18) is provided between the flanging die (15) and the flanging punch (16); the spacing of the flanging gap (17) is the same as the thickness of the designed flanging surface (8).

2. A process for controlling the rounded corners of the appearance contour of an automobile cover as claimed in claim 1, characterized in that: Before selecting a defined vector direction in the Pull Direction option, the following steps are also included: Select the straight contour type in the Contour Type option, select Use Draft Direction in the Subtype option, and select Appearance Modeling Contour in the Guide Curve 1 option.

3. A process for controlling the rounded corners of the appearance contour of an automobile cover as claimed in claim 1, characterized in that: After generating the required swept surface as the design folding edge surface (8) of the fender outer panel (2), the following steps are also included: The edge fillet command is used to complete the fillet operation of the fender appearance contour fillet (7), thereby completing the design of the fender outer panel appearance contour folding structure feature.

4. A process for controlling the rounded corners of the appearance contour of an automobile cover as claimed in claim 1, characterized in that: The draft angle is 3° to 5°.

5. A process for controlling the rounded corners of the appearance contour of an automobile cover as claimed in claim 1, characterized in that: A stretching surface is generated along the stamping flanging direction as a process flanging surface (18), wherein the process flanging surface (18) is a spatial single curved surface, and the following steps are also included: By using the edge filleting command, the appearance contour line (11) to be filleted is selected to generate the fender appearance contour fillet (7), thereby completing the fender outer panel (2) appearance contour folding structure process design.

6. A process for controlling the rounded corners of the appearance contour of an automobile cover as claimed in claim 1, characterized in that: The three-dimensional design software is Catia or Pro-E.

7. A process for controlling the rounded corners of the appearance contour of an automobile cover as claimed in claim 1, characterized in that: The fender outer panel (2) is a front fender outer panel of an automobile.

8. A process for controlling the rounded corners of the appearance contour of an automobile cover as claimed in claim 1, characterized in that: The exterior styling contour line (11) intersects with the exterior styling surface of the automobile, and the exterior styling contour line (11) is a splicing contour line of the fender outer panel (2) and the hood outer panel (1) and / or a splicing contour line of the fender outer panel (2) and the door panel outer panel (3).

9. A process for controlling the rounded corners of the appearance contour of an automobile cover as claimed in claim 1, characterized in that: The value of the angle between the designed folding edge surface (8) and the vector direction defining the draft angle at any cross section is consistent with the defined draft angle.

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