Resin outer panel member

Abstract

To provide a resin outer panel member that is able to prevent defect in the exterior caused by thermal distortion regardless of its shape.SOLUTION: The resin outer panel member 10, which constitutes an exterior portion of a vehicle together with an inner panel member, includes: a restricting region 13 that constitutes at least a part of the outer panel member 10 and is restricted in extension along a surface thereof while kept fixed to a peripheral edge part of the inner panel member; and a convex portion 14 projecting toward an external-surface side of the restricting region 13 or a concave portion receding toward an internal-surface side of the restricting region 13, which constitutes a part of the restricting region 13. A thickness dimension t1 of the convex portion 14 or the concave portion is set smaller than a thickness dimension t2 of a region 13a of the restricting region 13 adjacent to the convex portion 14 or the concave portion.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a resin outer panel member, and more particularly to a technique for suppressing deformation of a resin outer panel member due to thermal stress. [Background technology]

[0002] In recent years, as part of efforts to reduce environmental impact by improving fuel efficiency in vehicle tailgates such as automobiles, at least one of the tailgate outer and tailgate inner components that make up the tailgate has been formed from resin, which is lighter than metal (see, for example, Patent Document 1).

[0003] In this case, the back door outer is adhesively fixed to the peripheral edge of the back door inner in order to simultaneously provide a sealing structure and a fixing structure (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-124346 [Patent Document 2] Japanese Patent Application Laid-Open No. 2018-167697 Summary of the Invention [Problem to be solved by the invention]

[0005] Because the tailgate outer panel is located on the vehicle's exterior surface, it is prone to temperatures higher than the tailgate inner panel. For example, if a vehicle is left in the scorching heat of midsummer for an extended period of time, the temperature of the tailgate outer panel (particularly the top surface of the tailgate outer upper panel) can reach 80-100°C. In such high temperatures, the tailgate outer panel attempts to thermally expand. However, if the tailgate outer panel is adhesively fixed to the periphery of the tailgate inner panel as described above, the adhesive restrains the tailgate outer panel, restricting deformation along its plane, resulting in thermal stress. In particular, if the tailgate outer panel is made of resin, the amount of thermal expansion increases compared to a metal panel. Furthermore, this type of panel member may have a protruding portion on the exterior surface, known as a bulge structure, to avoid interference with components located on the interior (such as hinge reinforcements in the case of the tailgate outer panel). However, such portions have high geometric rigidity (resistance to deformation due to their shape) and are prone to becoming points of stress concentration. As a result, the thermal stress (thermal strain) generated in the back door outer increases beyond a predetermined level, which may result in deformation (poor appearance) such that the top surface of the back door outer upper becomes wavy and concave along its width direction.

[0006] In view of the above circumstances, the technical problem to be solved in this specification is to provide a resin outer panel member that can prevent the occurrence of poor appearance due to thermal distortion regardless of the shape of the panel member. [Means for solving the problem]

[0007] The above-mentioned problems are solved by a resin outer panel member according to the present invention, which is a resin outer panel member that, together with an inner panel member, constitutes an exterior part of a vehicle, and is characterized in that it has a restriction area that forms at least a part of the outer panel member and is fixed to the peripheral edge of the inner panel member and restricts stretch along the surface, and a convex portion that forms a part of the restriction area and protrudes toward the outer surface of the restriction area or a concave portion that is recessed toward the inner surface of the restriction area, and the thickness dimension of the convex portion or the concave portion is set smaller than the thickness dimension of a region of the restriction area adjacent to the convex portion or the concave portion.

[0008] The inventors performed thermal stress analysis on a resin outer panel member under specified constraint conditions to examine its deformation. The results revealed that stress concentration is significant in or near areas with higher geometric rigidity than adjacent areas, such as bulge structures, and that displacement (concave deformation) occurs in the thickness direction from the stress concentration point. In light of this finding, the present invention sets the thickness of a convex or concave portion provided in a restriction area that constitutes at least a part of the outer panel member smaller than the thickness of an area of ​​the restriction area adjacent to the convex or concave portion. This configuration prevents stress concentration in the convex or concave portion and suppresses thermal distortion in the restriction area. Therefore, the present invention makes it possible to minimize the occurrence of cosmetic defects, such as concave deformation, in a resin outer panel member.

[0009] In addition, in the resin outer panel member of the present invention, the thickness dimension of the peripheral side region of the restriction area that is adjacent to the convex or concave portion on the peripheral side of the restriction area may be set to be smaller than the thickness dimension of the central side region that is adjacent to the convex or concave portion on the central side of the restriction area.

[0010] In addition to the thickness of the convex or concave portion as described above, the thickness of the peripheral region adjacent to the convex or concave portion on the peripheral side of the restriction region can be set smaller than the thickness of the central region of the restriction region, so that thermal expansion occurring in the restriction region can be released to the relatively thinner peripheral region, which further suppresses thermal distortion occurring in the restriction region, making it possible to more reliably prevent poor appearance due to concave deformation, etc.

[0011] In addition, in this case, in the resin outer panel member of the present invention, convex or concave portions may be provided on both longitudinal sides of the regulating area, and the thickness dimensions of each convex or concave portion and the peripheral side area adjacent to the longitudinal outside of the regulating area may both be set smaller than the thickness dimension of the central side area.

[0012] As described above, when the convex or concave portions are provided on both sides of the restriction area in the longitudinal direction, the thickness of each of the convex or concave portions and the peripheral region adjacent to the restriction area in the longitudinal direction can be set smaller than the thickness of the central region, so that thermal expansion occurring in the restriction area can be evenly released to both sides in the longitudinal direction. This effectively suppresses thermal distortion occurring in the central region of the restriction area, thereby reliably preventing concave deformation and the like occurring in the central region.

[0013] The resin outer panel member described above can prevent poor appearance due to thermal distortion regardless of its shape, and can therefore be suitably provided as a resin tailgate outer upper in which, for example, a restriction area is provided on the top surface of the tailgate outer upper, and a bulge structure to avoid interference with the hinge reinforcement is provided as a convex portion on both sides of the width of the top surface. [Effects of the Invention]

[0014] As described above, the resin outer panel member according to the present invention can prevent appearance defects caused by thermal distortion regardless of its shape. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a perspective view of a resin back door outer upper according to one embodiment of the present invention. FIG. [Figure 2] FIG. 1 is a plan view of the outer upper back door. [Figure 3] 2. (a) is a cross-sectional view taken along line AA of the central region, (b) is a cross-sectional view taken along line BB of the convex portion, and (c) is a cross-sectional view taken along line CC of the peripheral region, respectively. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, a resin outer panel member according to one embodiment of the present invention will be described with reference to the drawings. In this embodiment, the resin outer panel member will be described using an automobile back door outer upper as an example.

[0017] 1 shows a perspective view of a tailgate outer upper 10 according to one embodiment of the present invention. The tailgate outer upper 10 is made of resin and constitutes a tailgate for an automobile together with a tailgate inner (not shown) as an inner panel member, and has a rear spoiler 11 integrally formed therewith.

[0018] In this embodiment, the back door outer upper 10 is fixed to the peripheral edge of the back door inner by adhesive or the like. Therefore, almost the entire peripheral edge 10a of the back door outer upper 10 is adhesively fixed to the peripheral edge of the back door inner. In this case, the entire top surface 12 of the back door outer upper 10 becomes the restriction area 13 according to the present invention. Furthermore, of the peripheral edge of the top surface 12, the open side edge 12a extending in the width direction becomes the adhesively fixed part with the back door inner, and the remaining part becomes the part with relatively high shape rigidity, such as the bent part 12b.

[0019] One or more convex portions 14 are provided on the top surface 12 of the back door outer upper 10. In this embodiment, as shown in FIG. 2, a pair of convex portions 14 forming a bulge structure are arranged on both sides of the top surface 12 in the width direction. In this case, each convex portion 14 is set to a position and size that matches the position and size of an object (such as a hinge reinforcement) that should be prevented from interfering with the back side of the top surface 12. More specifically, in this illustrated example, each convex portion 14 has a curved shape and is provided from an open side edge 12a extending in the width direction on the peripheral edge of the top surface 12 to a central position in the front-rear direction of the top surface 12. Furthermore, the convex portion 14 is highest at the open side edge 12a.

[0020] Next, the relationship between the thickness dimensions in the restriction area 13 will be described mainly with reference to FIG.

[0021] FIG. 3(a) shows a cross-sectional view (AA cross-sectional view shown in FIG. 2) of the region of the restriction area 13 where the convex portion 14 is provided. FIG. 3(b) shows a cross-sectional view (BB cross-sectional view shown in FIG. 2) of the central region 13a of the restriction area 13, which is adjacent to the convex portion 14 on the central side of the restriction area 13. FIG. 3(c) shows a cross-sectional view (CC cross-sectional view shown in FIG. 2) of the peripheral region 13b of the restriction area 13, which is adjacent to the convex portion 14 on the peripheral side of the restriction area 13. As shown in these figures, the thickness dimension t1 of the convex portion 14 is set smaller than the thickness dimension t2 of the central region 13a. In this embodiment, the thickness dimension t3 of the peripheral region 13b is also set smaller than the thickness dimension t2 of the central region 13a.

[0022] Here, from the viewpoint of minimizing deformation due to thermal strain of the top surface portion 12 (restriction region 13), the thickness dimension t1 of the convex portion 14 is preferably 95% or less, and more preferably 92% or less, of the thickness dimension t2 of the central region 13a. From the same viewpoint, the thickness dimension t3 of the peripheral edge region 13b is preferably 95% or less, and more preferably 92% or less, of the thickness dimension t2 of the central region 13a. These numerical ranges are set based on the results of a thermal stress analysis of the back door outer upper 10 shown in, for example, Figures 1 to 3.

[0023] The thickness t1 of the convex portion 14 and the thickness t3 of the peripheral edge region 13b may be the same or different.

[0024] In addition, while the illustrated example illustrates a case in which the thickness dimension t1 of the convex portion 14 is uniform throughout its entire area in the front-to-rear direction, this is of course not limited to this. In this embodiment, the thickness dimension t1 of the convex portion 14 may have a predetermined distribution as long as the above-mentioned dimensional relationship is satisfied. The thickness dimension t2 of the central region 13a and the thickness dimension t3 of the peripheral region 13b may also have a predetermined distribution.

[0025] As described above, in the resin back door outer upper 10 according to this embodiment, the thickness dimension t1 of the convex portion 14 provided in the restriction area 13 of the top surface portion 12 is set smaller than the thickness dimension t2 of the area of ​​the restriction area 13 adjacent to the convex portion 14 (here, the central area 13a). This configuration makes it possible to avoid a situation in which stress is concentrated on the convex portion 14 and suppress thermal distortion occurring in the restriction area 13. Therefore, with the back door outer upper 10 according to this embodiment, it is possible to prevent, as much as possible, situations in which poor appearance such as concave deformation occurs.

[0026] Although one embodiment of the present invention has been described above, the resin outer panel member according to the present invention can also have other configurations than those described above without departing from the spirit of the invention.

[0027] For example, in the above embodiment, the thickness dimension t1 of the convex ridge portion 14 is smaller than the thickness dimension t2 of the central region 13a, and the thickness dimension t3 of the peripheral region 13b is smaller than the thickness dimension t2 of the central region 13a. However, this is not limiting. For example, depending on the size of the convex ridge portion 14, the thickness dimension t2 of the central region 13a and the thickness dimension t3 of the peripheral region 13b may be the same, and the thickness dimension t1 of the convex ridge portion 14 may be smaller than both the thickness dimension t2 of the central region 13a and the thickness dimension t3 of the peripheral region 13b. Even in this configuration in which only the convex ridge portion 14 is relatively thin, the effects of the present invention can be achieved.

[0028] In addition, in the present embodiment, the convex portion 14 forming the bulge structure is the target of the thinning according to the present invention, but of course, this is not limited to this. For example, although not shown, if both widthwise ends of the back door outer upper 10 are shaped to be raised, these raised portions at both ends may be made convex portions, and the thickness dimension thereof may be set smaller than that of the remaining region of the restriction area 13.

[0029] In the above embodiment, the thickness t1 of the convex portion 14 is set to be relatively small, but this is not limiting. For example, although not shown, if a recessed portion is provided on the inner surface side of the restriction area 13, the thickness of this recessed portion may be set to be smaller than the thickness of the restriction area 13 excluding the recessed portion.

[0030] In the above description, the present invention has been described as being applied to the automobile back door outer upper 10, but it is of course possible to apply the present invention to other panel components. That is, the convex or concave portion provided in the restriction area of ​​any resin outer panel member may be formed relatively thin, as long as it constitutes the exterior of the vehicle together with the inner panel member. [Explanation of symbols]

[0031] 10 Back door outer upper 10a Periphery 11 Rear spoiler 12 Top section 12a Open side edge 12b Bend part 13 Regulatory Area 13a Central area 13b Peripheral region 14 Convex part t1 Thickness dimension (convex part) t2 Thickness dimension (center area) t3 Thickness dimension (peripheral area)

Claims

[Claim 1] A resin outer panel member that constitutes an exterior portion of a vehicle together with an inner panel member, a restriction region that forms at least a part of the outer panel member and that restricts elongation along a surface thereof when the outer panel member is fixed to a peripheral edge portion of the inner panel member; a convex portion that forms a part of the restriction area and that protrudes toward the outer surface of the restriction area or a concave portion that is recessed toward the inner surface of the restriction area, A resin outer panel member, wherein the thickness dimension of the convex portion or the concave portion is set smaller than the thickness dimension of a region of the restriction region adjacent to the convex portion or the concave portion.

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