Panel body manufacturing method

Abstract

A method for producing a panel structure Dp including a first panel Ip obtained by butting and joining two panel materials B1, B2 differing in plate thickness and a second panel Op disposed on the outer side of the first panel Ip and connected thereto by hemming, the method comprising: press-forming the first panel Ip into a state in which the main surfaces, on the joint W side, of the two panel materials B1, B2 are flush with each other and a slant portion S due to the plate thickness difference appears on the reverse side therefrom; disposing the first panel Ip so that the main surfaces thereof on the joint W side face the second panel Op; and connecting the second panel Op by hemming to an edge portion, including some of the slant portion S, of the first panel Ip. This panel structure Dp combines inside and outside appearance quality.

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a panel body having a first panel and a second panel, and in particular to a method for manufacturing a panel body having a first panel having a structure in which two panel materials of different thicknesses are joined together, and a second panel that is positioned on the outside of the first panel and joined by hemming. [Background technology]

[0002] Conventionally, a method for manufacturing a panel body as described above is disclosed, for example, in Patent Document 1. The method for manufacturing a panel body described in Patent Document 1 is a method for manufacturing a panel body including a first panel made of different thickness materials formed by butt-joining a plurality of members having different plate thicknesses and welding them together, and a second panel facing the first panel.

[0003] The manufacturing method involves hemming the edge of the first panel, which includes a step due to a difference in thickness, onto the second panel so as to sandwich the edge. In this manufacturing method, the step at the edge of the first panel is partially removed, and then the second panel is hemmed to join the first and second panels, thereby preventing or suppressing distortion in the second panel. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2013-86153 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the conventional panel body manufacturing method described above, the joined portions (weld marks) between the components of the first panel are exposed on the surface of the panel body, which makes it difficult to achieve both high quality in appearance both inside and outside the panel body, and solving this problem was a challenge.

[0006] The present invention was made in response to the above-mentioned conventional problems, and aims to provide a manufacturing method that can achieve good external appearance quality both inside and outside the panel body when manufacturing a panel body having a first panel structure formed by joining two panel materials of different thicknesses, and a second panel that is positioned outside the first panel and connected by hemming. [Means for solving the problem]

[0007] The method for manufacturing a panel body according to the present invention includes a first panel having a structure in which two panel materials of different thicknesses are butt-joined, and a second panel arranged on the outside of the first panel and connected by hemming. This method for manufacturing a panel body includes press-forming the first panel so that the main surfaces of the two panel materials facing the joined portions are flush with each other and have an inclined portion due to the difference in thickness on their reverse sides, and then arranging the main surface of the first panel facing the joined portion toward the second panel. The method for manufacturing a panel body is characterized in that the first panel and the second panel are joined by hemming the second panel along the edge of the first panel, including the inclined portion. [Effects of the Invention]

[0008] By adopting the above-described configuration, the manufacturing method of the panel body according to the present invention is able to manufacture a panel body having a first panel structured by joining two panel materials of different thicknesses together, and a second panel that is positioned on the outside of the first panel and connected by hemming, such that the joined portions of the panel materials of the first panel are positioned on the inside of the panel body, thereby achieving good appearance quality both inside and outside the panel body. [Brief explanation of the drawings]

[0009] [Figure 1] In the first embodiment of the method for manufacturing a panel body according to the present invention, (A) is a perspective view showing a first panel, (B) is a perspective view showing the first panel after press processing, and (C) is a perspective view showing a main part of the panel body. [Figure 2] FIG. 1A is a plan view of the lower mold of a press mold; FIG. 1B is a cross-sectional view of the press mold taken along line AA in FIG. A; and FIG. 1C and FIG. 1D are cross-sectional views of the press mold taken along line BB in FIG. A, where FIG. 1C shows the main parts before molding, and FIG. 1D shows the main parts after molding. [Figure 3] As a specific example of hemming, (A) is a cross-sectional view showing a hemming process using a forming die from top to bottom, and (B) is a cross-sectional view showing a hemming process using a forming roller from top to bottom. [Figure 4] 1A and 1B are diagrams showing an example of a method for manufacturing a panel body using a molding die for hemming, in which FIG. 1A is a cross-sectional view showing the state during pre-forming, and FIG. 1B is a cross-sectional view showing the state during main forming. [Figure 5] FIG. 10 is a diagram showing an example of using a hemming forming roller in a manufacturing method for a panel body, and is a graph showing the amount of surface change of the second panel when (A) the second panel has a convex curved surface facing outward, (B) the second panel has a concave curved surface facing outward, and (C) the second panel is flat. DETAILED DESCRIPTION OF THE INVENTION

[0010] 1 to 5 are diagrams showing one embodiment of a method for manufacturing a panel body according to the present invention. The panel body of this embodiment is a door panel Dp of an automobile, and includes an inner panel Ip as a first panel and an outer panel Op as a second panel.

[0011] As shown in Figure 1(A), the inner panel Ip has a structure in which two panel materials B1 and B2 of different thicknesses are butt-joined together. This inner panel Ip is a so-called tailored blank material, with panel material B1, which has a relatively large thickness t1, positioned on the upper side of the door, and panel material B2, which has a relatively small thickness t2, positioned on the lower side of the door.

[0012] The inner panel Ip has a structure in which both panel materials B1 and B2 are butted together and integrated by, for example, the well-known friction stir welding (FSW). As a result, the inner panel Ip has a welded portion W along a step caused by the difference in plate thickness between the two panel materials B1 and B2. In the case of friction stir welding, tool marks appear on the surface of the welded portion W.

[0013] The outer panel Op is a metal plate that forms the exterior of the door panel Dp. It is positioned opposite the outer side of the inner panel Ip and is connected to the inner panel Ip by hemming its edges, as shown in Figure 1(C).

[0014] In the manufacturing method of the panel body, the inner panel Ip is pressed to form the two panel materials B1, B2 so that their main surfaces facing the joined portion W are flush with each other, as shown in Figure 1(B). As a result, the inner panel Ip has a sloped portion S formed on the back side of the joined portion W due to the difference in thickness between the two panel materials B1, B2. Note that the difference in thickness between the two panel materials B1, B2 is exaggerated in the drawing for ease of understanding, and the actual gradient of the sloped portion S is smaller than shown.

[0015] The press working of the inner panel Ip can be performed using a press die shown in Fig. 2. The press die includes a fixed lower die 51 shown in Figs. 2(A) and (B) and an upper die 52 that is movable up and down and faces the lower die 51. As shown in Figs. 2(C) and (D), in the portion that forms the to-be-joined portion W of the inner panel Ip, the upper surface of the lower die 51 is flat, and the lower surface of the upper die 52 has a shape that is the inverse of the surface of the inner panel Ip that faces the to-be-joined portion W.

[0016] Then, as shown in Figure 2(C), the press mold is placed on the lower mold 51 with the surface of the inner panel Ip facing downward toward the to-be-joined portion W, and then the upper mold 52 is lowered to flatten the surface of the inner panel Ip facing the to-be-joined portion W, as shown in Figure 2(D), and form a sloped portion S on the back side of the to-be-joined portion W.

[0017] Next, in the manufacturing method of the panel body, as shown in Figure 1(C), the main surface of the inner panel Ip on the side of the joined portion W is placed on the outer panel Op side, and the inner panel Ip and the outer panel Op are connected by hemming the outer panel Op along the edge of the inner panel Ip including the inclined portion S.

[0018] The outer panel Op can be hemmed using a forming die 11 as shown in Fig. 3(A) or using forming rollers 21 and 22 as shown in Fig. 3(B). In either hemming method, a flange F is formed on the edge of the outer panel Op in a previous process.

[0019] In hemming using the forming die 11, a lower die 12, a preforming die 13 arranged on the upper die side (not shown), and a main forming die 14 also arranged on the upper die side are used. The preforming die 13 has an inclined surface 13A for pre-bending.

[0020] To perform hemming, the outer panel Op is placed on the lower mold 12 with the flange F facing upward, and then the edge of the inner panel Op is placed so that it is aligned with the vicinity of the flange F. Then, as shown in the upper part of FIG. 3(A), the flange F is pre-bent to an appropriate angle (for example, 45 degrees) using the inclined surface 13A of the pre-forming mold 13. Then, as shown in the lower part of FIG. 3(A), the flange F is bent using the main forming mold 14 so as to sandwich the edge of the inner panel Ip, thereby completing the hemming.

[0021] Hemming using a forming roller uses a lower mold 12, a preforming roller 21, and a main forming roller 22. The preforming roller 21 has a conical surface 21A, and the main forming roller 22 is cylindrical.

[0022] To perform hemming, the outer panel Op and inner panel Ip are positioned in the same manner as in the forming mold 11, and as shown in the upper part of Figure 3(B), the preliminary forming roller 21 is rolled along the edge of the outer panel OP, and the conical surface 21A pre-bends the flange F to an appropriate angle (for example, 45 degrees), and then, as shown in the lower part of Figure 3(B), the main forming roller 22 is used to bend the flange F so as to sandwich the edge of the inner panel Ip, thereby completing the hemming.

[0023] In the manufacturing method of a panel body according to the present invention, when hemming an outer panel Op using a forming die 11, as shown in the upper part of Fig. 4, a lower die 12 and a preforming die 13 having a stepped forming surface FS corresponding to the two panel materials B1, B2 and the inclined portion S of the inner panel Op are used to pre-bend the flange F to an appropriate angle (for example, 45 degrees). The forming surface FS can also have a structure with an inclined surface that follows the inclined portion S, but good hemming is possible even if it is stepped as in the illustrated example. Fig. 4 is a cross-sectional view taken along the arrow AA in Fig. 1(C).

[0024] Thereafter, as shown in the lower part of Figure 4, a main molding die 14 having a stepped molding surface FS corresponding to the two panel materials B1, B2 and the inclined portion S of the inner panel Op is used to bend the flange F so as to sandwich the edge of the inner panel Ip, thereby completing the hemming.

[0025] In the panel body manufacturing method according to the present invention, when hemming the outer panel Op using the preliminary forming roller 21 and the main forming roller 22, the preliminary forming roller 21 and the main forming roller 22 roll along the arrangement direction of the two panel materials B1 and B2, as shown in Fig. 3(B). In this case, in a more preferred embodiment of the panel body manufacturing method, the forming rollers 21 and 22 roll in a direction from the thinner panel material B2 through the inclined portion S to the thicker panel material B1, thereby hemming the outer panel Op.

[0026] In this embodiment, since the panel body is a door panel Dp, the outer panel Op has a curved surface in many cases. In this case, it is desirable that the inclined portion S of the inner panel Ip is disposed within the range of the curved surface.

[0027] The reason for this is that when hemming is performed using the forming rollers 21 and 22, as shown in Figure 5, the feed direction of the forming rollers is defined as the forward direction from the panel material B2 with a smaller plate thickness through the inclined section S to the panel material B1 with a larger plate thickness, and the reverse direction is defined as the reverse direction. This results in different amounts of surface change in the outer panel Op depending on the curvature direction of the outer panel Op.

[0028] Specifically, as shown in Fig. 5, when the outer panel Op has a curved surface that is convex toward the exterior (outside of the vehicle), the amount of change in the surface of the outer panel Op is smaller in the forward order than in the reverse order. Also, when the outer panel Op has a curved surface that is concave toward the exterior, the amount of change in the surface of the outer panel Op is smaller in both the forward and reverse orders than when the surface is convex toward the exterior, and in particular, the amount of change in the surface of the outer panel Op is smaller in the forward order than in the reverse order. Furthermore, when the outer panel Op is flat, there is a risk that the appearance quality of the outer panel Op will be impaired when the outer panel Op is rotated in the reverse order, but the amount of change in the surface of the outer panel Op is extremely small when the outer panel Op is rotated in the forward order.

[0029] From the above, when hemming is performed using a forming roller, not only when the outer panel Op is flat but also when the outer panel Op has a curved surface, by rolling the forming roller in the forward feed direction, i.e., from the panel material B2 with the smaller plate thickness through the inclined portion S to the panel material B1 with the larger plate thickness, distortion, etc., in the outer panel Op can be suppressed and good appearance quality can be obtained.

[0030] The above-mentioned method for manufacturing a panel body involves manufacturing a door panel (panel body) Dp having an inner panel (first panel) Ip and an outer panel (second panel) Op, by pressing the inner panel Ip to form it so that the main surfaces on the side of the joined portion W are flush with each other and so that a sloping portion S appears on the back side thereof, and then arranging the main surface of the inner panel Ip on the side of the joined portion W on the outer panel Op side, and hemming the outer panel Op along the edge of the inner panel Ip including the sloping portion S, thereby connecting the inner panel Ip and the outer panel Op.

[0031] As a result, according to the above-described manufacturing method of the panel body, as shown by the dotted line in Figure 1(C), the joined portion (tool mark) W between the panel materials B1 and B2 of the inner panel Ip is positioned on the inside of the door panel Dp, and distortion of the outer panel Op is also suppressed, so that it is possible to achieve good appearance quality both inside and outside the door panel Dp.

[0032] Furthermore, as shown by the imaginary lines in Figure 1(C), rubber parts G such as weather strips are attached to the side surfaces of the door panel Dp where the thickness is apparent. In this case, if the joined portions (tool marks) W are exposed to the outside of the inner panel Ip, the rubber parts G may come into contact with the joined portions W, potentially reducing durability. In contrast, in the door panel Dp manufactured using the above manufacturing method, the joined portions W are positioned internally, eliminating contact between the joined portions W and the rubber parts G and maintaining the durability of the rubber parts G.

[0033] Furthermore, in the above-mentioned method for manufacturing a panel body, by hemming the outer panel Op using a molding die 11 having a molding surface FS corresponding to the two panel materials B1, B2 and the inclined portion S of the inner panel Ip, distortion caused by the inclined portion S is less likely to be transferred to the outer surface of the outer panel Op, thereby improving the appearance quality of the hemmed portion.

[0034] Furthermore, in the above-mentioned method for manufacturing the panel body, by hemming the outer panel Op using forming rollers 21, 22 that roll along the arrangement direction of the two panel materials B1, B2, distortion caused by the inclined portion S is less likely to be transferred to the outer surface of the outer panel Op, thereby improving the appearance quality of the hemmed portion.

[0035] Furthermore, in the above-described method for manufacturing a panel body, the forming rollers 21, 22 roll in a direction from the thinner panel material B2 through the inclined portion S to the thicker panel material B1 to perform hemming on the outer panel Op, thereby further suppressing the occurrence of distortion due to the inclined portion S and achieving further improvement in the appearance quality of the hemmed portion, particularly in a structure where there is a large difference in thickness between the panel materials B1 and B2.

[0036] Furthermore, the above-mentioned manufacturing method of the panel body is structured so that the outer panel Op has a curved surface and the inclined portion S of the inner panel Ip is arranged within the range of the curved surface, thereby further suppressing the occurrence of distortion due to the inclined portion S even in a structure where there is a large difference in plate thickness between the panel materials B1 and B2, and further enhancing the weight reduction effect.

[0037] Furthermore, the above-mentioned method for manufacturing a panel body is suitable for manufacturing not only door panels Dp but also panel bodies such as automobile engine hood panels and truck lid panels, particularly panel bodies that are opened and closed, and can provide panel bodies with excellent appearance quality both inside and outside. [Explanation of symbols]

[0038] B1, B2 panel material Dp door panel (panel body) FS molding surface IP inner panel (first panel) Op outer panel (second panel) S slope part W Part to be joined (tool marks) 11 Molding mold 21 Preforming roller (forming roller) 22 forming rollers (forming rollers)

Claims

1. When manufacturing a panel body including a first panel having a structure in which two panel materials of different thicknesses are butt-joined together, and a second panel disposed on the outside of the first panel and connected by hemming, The first panel is pressed to form the two panels so that the main surfaces of the panels facing the joined portions are flush with each other and a sloped portion due to a difference in plate thickness is formed on the back side of the panels. a main surface of the first panel on the side of the joined portion is disposed on the second panel side; A method for manufacturing a panel body, comprising: hemming the second panel along the edge of the first panel, including the inclined portion, thereby connecting the first panel and the second panel.

2. When hemming the second panel, 2. The method for manufacturing a panel body according to claim 1, wherein a mold having molding surfaces corresponding to the two panel materials and the inclined portion of the first panel is used.

3. When hemming the second panel, 2. The method for manufacturing a panel body according to claim 1, wherein a forming roller is used that rolls along the arrangement direction of the two panel materials.

4. 4. The method for manufacturing a panel body according to claim 3, wherein the forming roller is rolled in a direction from the panel material having a smaller plate thickness through the inclined portion to the panel material having a larger plate thickness, thereby hemming the second panel.

5. the second panel has a curved surface; The method for manufacturing a panel body according to claim 1, wherein the inclined portion of the first panel is disposed within the range of the curved surface.

6. The panel body is at least one of an automobile door panel, an engine hood panel, and a truck lid panel, 2. The method for manufacturing a panel body according to claim 1, wherein the first and second panels are an inner panel and an outer panel.

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