Edge covering process method

Abstract

The invention discloses an edge covering process method, and relates to the technical field of edge covering processes, the edge covering process method is applied to edge covering connection of an outer plate and a plurality of inner plates, and the edge covering process method comprises the following steps: obtaining an angle design range calculated according to an avoidance gap design value and the overlap amount of the inner and outer plates; adjusting the spliced side end of the inner plate to a corresponding inclination angle according to an angle design range; and after the outer plate is folded and wraps the end part of the inner plate, the outer plate is pressed through a roller. According to the technical scheme, the side ends of the multiple inner plates are obliquely arranged, under the condition that the design gaps between the inner plates are not changed, the situation of roller air pressure is reduced, specifically, the angle design range is calculated according to the receding gap design value and the lap joint amount of the inner plates and the outer plates, and the spliced side ends of the inner plates are designed according to the obtained angle design range; and it is guaranteed that inner plate supports exist in the vertical advancing direction of the rolling wheels, and therefore the problem that stamping recesses appear on the appearance face after edge covering and pressing are solved.

Description

Technical Field

[0001] The invention relates to the field of hemming art, and in particular to a hemming process method. Background Art

[0002] The current automobile industry is developing rapidly in terms of styling design. The hemming connection structure design of automobile sheet metal covering parts, which is highly related to the appearance, is an important part of the automobile manufacturing process, and is related to the appearance quality and structural strength of the body in white. In the automobile manufacturing industry, the manufacturing-oriented design concept can minimize manufacturing costs, improve product quality and shorten the development cycle. Usually, the hemming connection structure design is to use the hemming connection process to make the outer panel wrap the inner panel or the inner panel wrap the outer panel, forming a connection between the inner and outer panels and a safe part edge. For the same section of hemming, especially in the appearance area, the hemming connection structure is designed to connect the outer panel and the inner panel as a whole, and the complete inner panel hemming surface is a necessary condition to ensure a good hemming appearance.

[0003] For the inner panel shape with special structure, it may be impossible to achieve integrated stamping forming, there may be problems such as excessive local stress, which may easily cause quality defects such as drawing cracking. It is necessary to cut the stamped inner panel into 2 or more sheet metal forms to ensure good stamping formability, and then manufacture it into an inner panel assembly through welding and other connection processes. If such a part adopts a common continuous hemming structure, at the inner panel connection part, because there is an unavoidable gap between the inner panels, the hemming pressure will cause obvious appearance quality defects at the corresponding position of the hemming appearance surface. Summary of the invention

[0004] The main purpose of the present invention is to provide a hemming process method, aiming to solve the problem of stamping depressions on the appearance surface in the current hemming process.

[0005] To achieve the above object, the present invention provides a hemming process method, which is applied to the hemming connection of an outer panel and a plurality of inner panels. The hemming process method comprises the following steps:

[0006] Obtain the angle design range calculated based on the avoidance clearance design value and the overlap amount of the inner and outer plates;

[0007] Adjust the side ends of the inner panels to the corresponding tilt angles according to the angle design range;

[0008] The outer panel is folded over to cover the end of the inner panel and then pressed together by rollers.

[0009] In one embodiment, the step of obtaining the angle design range calculated according to the avoidance clearance design value and the overlap amount of the inner and outer plates specifically includes:

[0010] Calculate the limit design gap based on the gap design tolerance;

[0011] The first limit angle value is calculated according to the limit design gap and the overlap amount of the inner and outer plates, and the second limit angle value is calculated according to the radius of the fillet on the inner plate surface;

[0012] The first limit angle value and the second limit angle value are respectively used as breakpoint values ​​to confirm the angle design range.

[0013] In one embodiment, the first limit angle value is A, the limit design gap is a, the overlap amount of the inner and outer plates is b, and sinA>a / b.

[0014] In one embodiment, the second limit angle value is B, where B<45°.

[0015] In one embodiment, the step of “folding the outer panel to cover the end of the inner panel and then pressing the outer panel with a roller” further includes:

[0016] Calculate the preset hemming thickness based on the inner plate thickness design value, outer plate thickness design value and the height gap between the inner and outer plates;

[0017] In the step of “folding the outer panel and making it cover the end of the inner panel, and then pressing it together with a roller”, the portion of the outer panel that covers the end of the inner panel after being folded is the hemming portion;

[0018] The formation of the hemming portion is determined according to a preset hemming thickness.

[0019] In one embodiment, the height gap between the inner and outer plates is C, 0.2mm≤C≤0.5mm.

[0020] In one embodiment, the step of determining the formation of the hemming portion according to the preset hemming thickness specifically includes:

[0021] Determine the distance between the edges of the inner and outer panels at the hemming location according to the preset hemming thickness;

[0022] Adjust the position of the inner panel according to the distance between the edges of the inner and outer panels at the hemming point.

[0023] In one embodiment, the step of “folding the outer panel to cover the end of the inner panel and then pressing the outer panel with a roller” further includes:

[0024] Glue is applied between the outer plate and the side of the inner plate facing away from the outer plate flange to form a glue-coated area on the outer plate.

[0025] In one embodiment, the distance from the edge of the glue-coated area close to the end of the inner panel to the folded portion of the outer panel is L1, and 0.3 mm ≤ L1 ≤ 0.7 mm.

[0026] In one embodiment, the end of the inner plate away from the edge is bent in a direction away from the outer plate;

[0027] The distance from the edge of the glue-coated area away from the end of the inner plate to the bending point of the inner plate is L2, and 0.3mm≤L2≤0.5mm.

[0028] The technical solution of the present invention reduces the occurrence of roller air pressure without changing the design gap between the inner plates by tilting the side ends of multiple inner plates. Specifically, the angle design range is calculated according to the design value of the avoidance gap and the overlap amount of the inner and outer plates, so that different angle design ranges can be adaptively obtained according to different design values. By designing the side ends of the spliced ​​inner plates according to the obtained angle design range, it is ensured that there is inner plate support in the vertical direction of the roller travel, thereby solving the problem of stamping depressions on the appearance surface after edge pressing. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0030] Figure 1 A schematic diagram of the partial structure of the inner plate and the outer plate during the hemming process of an embodiment provided by the present invention;

[0031] Figure 2 for Figure 1 Schematic diagram of the structure from one perspective of the inner and outer panels.

[0032] Description of Figure Numbers:

[0033] 1. Outer panel; 2. Inner panel; 3. Edge wrapping; 4. Glue coating area; 5. Outer panel folding area; 6. Inner panel bending area.

[0034] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0037] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0038] The styling design of the current automobile industry has developed rapidly. The hemming connection structure design of automobile sheet metal covering parts, which is highly related to the appearance, is an important part of the automobile manufacturing process, which is related to the appearance quality and structural strength of the white body. In the automobile manufacturing industry, the manufacturing-oriented design concept can minimize the manufacturing cost, improve product quality and shorten the development cycle. Usually, the hemming connection structure design is to make the outer panel wrap the inner panel or the inner panel wrap the outer panel through the hemming connection process to form a connection between the inner and outer panels and a safe part edge. For the same section of hemming, especially in the appearance area, the hemming connection structure is designed to connect the outer panel and the inner panel as a whole, and the complete inner panel hemming surface is a necessary condition to ensure a good hemming appearance.

[0039] For the inner panel shape with special structure, it may be impossible to achieve integrated stamping forming, there may be problems such as excessive local stress, which may easily cause quality defects such as drawing cracking. It is necessary to cut the stamped inner panel into 2 or more sheet metal forms to ensure good stamping formability, and then manufacture it into an inner panel assembly through welding and other connection processes. If such a part adopts a common continuous hemming structure, at the inner panel connection part, because there is an unavoidable gap between the inner panels, the hemming pressure will cause obvious appearance quality defects at the corresponding position of the hemming appearance surface.

[0040] The main purpose of the present invention is to provide a hemming process method, aiming to solve the problem of stamping depressions on the appearance surface in the current hemming process.

[0041] See also Figure 1 to Figure 2To achieve the above purpose, the present invention proposes a hemming process method, which is applied to the hemming connection of an outer panel 1 and a plurality of inner panels 2. The hemming process method comprises the following steps:

[0042] S10. Obtaining a design angle range calculated based on the design value of the avoidance gap and the overlap amount of the inner and outer plates.

[0043] It should be noted that the side ends of the plurality of inner panels 2 in the pressing direction are arranged in parallel, so as to ensure that the gaps between the inner panels 2 remain consistent, and the design value of the avoidance gap is the vertical distance between the side ends of two adjacent inner panels 2.

[0044] In the specific implementation, the avoidance clearance design value is D, and the tolerance is d. The maximum value of the avoidance clearance is D+d, and the minimum value is Dd. In order to avoid interference between the inner plates 2, it is necessary to ensure that Dd is greater than twice the inner plate 2 cutting edge dimension tolerance. When calculating the angle design range, the avoidance clearance design value is generally set to D+d, thereby ensuring that even with the maximum avoidance clearance, the occurrence of roller air pressure can be avoided.

[0045] It is worth mentioning that in order to ensure better hemming quality, the design value of the avoidance gap should be as small as possible.

[0046] S20, adjusting the spliced ​​side ends of the inner panels 2 to corresponding tilt angles according to the angle design range.

[0047] It should be noted that the inclination angle refers to the acute angle between the side end of the inner plate 2 and the direction perpendicular to the direction of travel of the roller, that is, when the angle is 0°, the side end of the inner plate 2 is perpendicular to the direction of travel of the roller, so that a depression will appear at the avoidance gap. Figure 1 In the figure, the tilt angle is marked as α.

[0048] S30, folding the outer panel 1 to cover the end of the inner panel 2, and then pressing them together with rollers.

[0049] The technical solution of the present invention reduces the occurrence of roller air pressure without changing the design gap between the inner plates 2 by tilting the side ends of multiple inner plates 2. Specifically, the angle design range is calculated according to the design value of the avoidance gap and the overlap amount of the inner and outer plates, so that different angle design ranges can be adaptively obtained according to different design values. By designing the side ends of the spliced ​​inner plates 2 according to the obtained angle design range, it is ensured that there is inner plate 2 support in the vertical direction of the roller travel, thereby solving the problem of stamping depressions on the appearance surface after edge pressing.

[0050] Furthermore, the step of S10, obtaining the angle design range calculated according to the avoidance clearance design value and the overlap amount of the inner and outer plates, specifically includes:

[0051] S11. Calculate the limit design gap based on the gap design tolerance.

[0052] It should be noted that the design value of the avoidance clearance is D, and the tolerance is d. The maximum value of the avoidance clearance is D+d, and the minimum value is Dd. In order to avoid interference between the inner plates 2, it is necessary to ensure that Dd is greater than twice the tolerance of the cutting edge dimension of the inner plate 2. When calculating the ultimate design clearance, it is necessary to ensure that under the maximum avoidance clearance, the occurrence of roller air pressure can be avoided. Generally, the design value of the avoidance clearance is set to D+d.

[0053] S12. Calculate the first limit angle value according to the limit design gap and the overlap amount of the inner and outer plates, and calculate the second limit angle value according to the radius of the fillet on the surface of the inner plate 2.

[0054] It should be noted that in order to eliminate stress concentration in parts, the corners of the inner plate 2 are provided with rounded corners. Due to the existence of the rounded corners, part of the inner plate 2 will be missing at the corners, resulting in the roller being empty. Especially for an excessively large inclination angle, the missing part at the rounded corner will be larger. At the same time, an excessively large inclination angle will also cause stress concentration.

[0055] It is worth mentioning that the first limit angle value is the minimum value, and the second limit angle value is the maximum value. By calculating the minimum value of the angle range according to the limit design gap and the overlap amount of the inner and outer plates, it is ensured that there is inner plate 2 support in the vertical direction of the roller movement, thereby solving the problem of stamping depressions on the appearance surface after edge pressing. By calculating the minimum value of the angle range according to the radius of the fillet on the surface of the inner plate 2, the roller air pressure caused by partial missing at the corner is prevented, and stress concentration is reduced at the same time.

[0056] It should be further explained that the first limit angle value is A, the limit design gap is a, and the overlap amount of the inner and outer plates is b, satisfying sinA>a / b. With such a design, in the vertical direction of the roller travel direction, the lower end of the overlap between the outer plate 1 and the inner plate 2 can be guaranteed to be supported by the inner plate 2, so that after the roller is pressed, no depression will occur, solving the problem of appearance deformation after edging. It is worth mentioning that since the inner plate 2 is provided with fillets at the corners, considering the partial loss of the inner plate 2 caused by the fillets, the inclination angle can be appropriately increased according to the fillet radius, and at the same time, it can also prevent local depressions caused by too few supporting parts.

[0057] It should also be noted that when the inclination angle is too large, the missing area at the corner is too large, which will cause extremely uneven force on the edge during pressing, resulting in local depression. To address the above defects, the second limit angle value is B, satisfying B<45°.

[0058] S13. Using the first limit angle value and the second limit angle value as breakpoint values ​​respectively to confirm the angle design range.

[0059] In one embodiment of the present invention, please refer to Figure 2 , the step of “S30, folding the outer panel 1 and making it cover the end of the inner panel 2, and then pressing by rollers” also includes:

[0060] Calculate the preset hemming thickness based on the inner plate thickness design value, outer plate thickness design value and the height gap between the inner and outer plates;

[0061] It is worth mentioning that the height gap between the inner and outer panels refers to the margin left in the height direction between the outer panel 1 and the inner panel 2 during the edge forming process. During the edge forming process, due to the poor plasticity of part of the outer panel 1, the bending part of the outer panel 1 will not be smooth enough, resulting in the final overlap between the outer panel 1 and the inner panel 2 being smaller than the design value. By leaving a height margin in advance, the design length of the outer panel 1 extending beyond the inner panel 2 is increased, ensuring sufficient overlap length of the inner and outer panels, while also preventing interference between the folded part of the inner panel 2 and the outer panel 1. Figure 2 The "c" in the figure represents the preset hemming thickness.

[0062] In the step of "S30, folding the outer panel 1 and making it cover the end of the inner panel 2, and then pressing it together with a roller", the part of the outer panel 1 that covers the end of the inner panel 2 after being folded is the edging part 3; the formation of the edging part 3 is determined according to the preset edging thickness.

[0063] It should be noted that, in the process of forming the edging portion 3, the gap between the inner panel 2 and the folded portion 5 of the outer panel must also be considered to prevent interference between the inner panel 2 and the outer panel 1. When the edging thickness is determined, it is also necessary to increase the length of the outer panel 1 extending beyond the inner panel 2, so that the folding print of the outer panel 1 is effectively optimized, thereby improving the overall quality and aesthetics of the edging portion 3.

[0064] Specifically, the height gap between the inner and outer plates is C, 0.2 mm ≤ C ≤ 0.5 mm. For example, the height gap C between the inner and outer plates is 0.2 mm, 0.25 mm, 0.3 mm, 0.5 mm, etc. In a specific embodiment, the height gap between the inner and outer plates is 0.2 mm.

[0065] Furthermore, the step of determining the formation of the hemming portion 3 according to the preset hemming thickness specifically includes:

[0066] Determine the distance between the edges of the inner and outer panels at the hemming location according to the preset hemming thickness;

[0067] Adjust the position of the inner panel 2 according to the distance between the edges of the inner and outer panels at the hemming.

[0068] It is worth mentioning that the distance between the edges of the inner and outer panels is the length of the outer panel 1 extending beyond the inner panel 2 in the direction perpendicular to the movement of the roller before the edging. By determining the distance between the edges of the inner and outer panels at the edging according to the edging thickness, it can be ensured that the outer panel 1 can be covered on the inner panel 2, thereby ensuring the integrity of the edging.

[0069] In one embodiment of the present invention, please refer to Figure 2 , the step of “S30, folding the outer panel 1 and making it cover the end of the inner panel 2, and then pressing by rollers” also includes:

[0070] Glue is applied between the outer panel 1 and the side of the inner panel 2 facing away from the flange of the outer panel 1 to form a glue-coated area 4 on the outer panel 1 .

[0071] By configuring in this way, the sealing between the inner plate 2 and the outer plate 1 is effectively improved by applying glue on the outer plate 1, thereby improving the stability of the inner plate 2 during the roller pressing process and preventing the inner plate 2 from moving.

[0072] Specifically, in order to prevent the glue from overflowing toward the outer panel folding part 5 during the lamination process, the position of the glue-coated area 4 is limited, and the distance from the edge of the glue-coated area 4 close to the end of the inner panel 2 to the outer panel folding part 5 is L1, 0.3mm≤L1≤0.7mm. For example, the distance L1 from the edge of the glue-coated area 4 close to the end of the inner panel 2 to the outer panel folding part 5 is 0.3mm, 0.35mm, 0.5mm, 0.7mm, etc. In a specific embodiment, the distance from the edge of the glue-coated area 4 close to the end of the inner panel 2 to the outer panel folding part 5 is 0.5mm.

[0073] Furthermore, in one embodiment, according to the process requirements, the end of the inner panel 2 away from the hemming is bent in a direction away from the outer panel 1; in order to prevent the occurrence of glue overflow toward the inner panel bending point 6 during the lamination process, the position of the glue-coated area 4 is limited, specifically, the distance from the edge of the end of the glue-coated area 4 away from the inner panel 2 to the inner panel bending point 6 is L2, 0.3mm≤L2≤0.5mm. For example, the distance L2 from the edge of the end of the glue-coated area 4 away from the inner panel 2 to the inner panel bending point 6 is 0.3mm, 0.35mm, 0.4mm, 0.5mm, etc. In a specific embodiment, the distance from the edge of the glue-coated area 4 away from the end of the inner panel 2 to the inner panel bending point 6 is 0.4mm.

[0074] It is worth mentioning that in order to reduce stress concentration, the inner panel bending part 6 is also provided with rounded corners. After the entire edging process is completed, the rounded corners of the inner panel bending part 6 will form an interference point with the outer panel 1. By limiting the scope of the glue coating area 4, the interference between the rounded corners of the inner panel bending part 6 and the outer panel 1 can be reduced.

[0075] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A hemming process method, applied to the hemming connection of an outer panel and a plurality of inner panels, characterized in that: The hemming process comprises the following steps: Obtain the angle design range calculated based on the avoidance clearance design value and the overlap amount of the inner and outer plates; Adjusting the side ends of the inner panels to corresponding tilt angles according to the angle design range; After the outer plate is folded and covered with the end of the inner plate, it is pressed together by rollers.

2. The hemming process according to claim 1, characterized in that: The step of "obtaining the angle design range calculated based on the avoidance clearance design value and the overlap amount of the inner and outer plates" specifically includes: Calculate the limit design gap based on the gap design tolerance; The first limit angle value is calculated according to the limit design gap and the overlap amount of the inner and outer plates, and the second limit angle value is calculated according to the radius of the fillet on the inner plate surface; The first limit angle value and the second limit angle value are respectively used as breakpoint values ​​to confirm the angle design range.

3. The hemming process according to claim 2, characterized in that: The first limit angle value is A, the limit design gap is a, the overlap amount of the inner and outer plates is b, and sinA>a / b.

4. The hemming process according to claim 2, characterized in that: The second limit angle value is B, where B<45°.

5. The hemming process according to claim 1, characterized in that: The step of "folding the outer panel to cover the end of the inner panel and then pressing the outer panel by rollers" also includes: Calculate the preset hemming thickness based on the inner plate thickness design value, outer plate thickness design value and the height gap between the inner and outer plates; In the step of "folding the outer panel and making it cover the end of the inner panel, and then pressing it together with a roller", the portion of the outer panel that covers the end of the inner panel after being folded is the hemming portion; The formation of the hemming portion is determined according to a preset hemming thickness.

6. The hemming process according to claim 5, characterized in that: The height gap between the inner and outer plates is C, 0.2mm≤C≤0.5mm.

7. The hemming process according to claim 5, characterized in that: The step of "determining the formation of the hemming portion according to the preset hemming thickness" specifically includes: Determine the distance between the edges of the inner and outer panels at the hemming location according to the preset hemming thickness; Adjust the position of the inner panel according to the distance between the edges of the inner and outer panels at the hemming point.

8. The hemming process according to claim 1, characterized in that: The step of "folding the outer panel to cover the end of the inner panel and then pressing the outer panel by rollers" also includes: Glue is applied between the outer plate and the side of the inner plate facing away from the outer plate flange to form a glue-coated area on the outer plate.

9. The hemming process according to claim 8, characterized in that: The distance between the edge of the glue-coated area close to the end of the inner plate and the folded portion of the outer plate is L1, and 0.3 mm ≤ L1 ≤ 0.7 mm.

10. The hemming process according to claim 8, characterized in that: The end of the inner plate away from the edge is bent in a direction away from the outer plate; The distance from the edge of the glue-coated area away from the end of the inner plate to the bending point of the inner plate is L2, and 0.3mm≤L2≤0.5mm.

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